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THE
ENGINEER'S AND MECHANIC's
E N C Y O L O PAE DIA,
COMPREHENDING
PRACTICAL ILLUSTRATIONS
OF
T H E M A C H IN E R Y
PROCESSES EMPLOYED IN EVERY DESCRIPTION OF MANUFACTURE
OF THE
BRITISH EMPIR. E.
*************
Qºliti) nearly &Tºuq Qſìjoušatti, 32ngtapingg.
*************
BY LUKE HEBERT,
civil ENGINEER,
EDITOR OF THE HIS TORY AND PROGRESS OF THE STEAM ENGINE, REGISTER OF A &TS, AND
JOURNAL OF PATENT INVENTION s, ETC.
IN TWO VOLUMES.
VOL. I.
“How much useful knowledge is lost by the scattered forms in which it is ushered
to the world ! How many solitary students spend half their lives in making discoveries
which had been perfected a century before their time, for want of a condensed exhibi-
tion of what is known l’—BUFF on.
LONDON :
THOMAS KELLY, 17, PATERNOSTER ROW.
M DCCCXXXVII.
L O N DO N :
P k I N T B D B Y R J C H A R D C L A Y.
BREAD-STR FET-III LL.
PR. E. F. A. C. E.
ALTHough many excellent treatises have been published
on the THEoRY of the Mechanical and Chemical Sciences,
none of them embrace a combined and general view of
the PRACTICAL APPLICATION of those sciences to the
operative arts and manufactures of the Empire. There
are, however, it must be admitted, several meritorious works
which treat partially on these subjects; but to the objection
of their contracted plan, may be added that of an incon-
venient arrangement for ready reference; and the practical
information that may be sought for in the voluminous
Cyclopaedias of Science and Literature, though attainable
only by laborious research, is, in most instances, so abstruse
or antiquated, as to be of no utility to those who are desirous
to avail themselves of the best combinations of inventive
skill, or to practise the new processes resulting from modern
chemical discovery.
The numerous applications to me, (in my professional capa-
city of a patent agent,) by inventors, for information on these
subjects, demonstrate the foregoing fact, and fully convince
me of the great advantages that would be conferred upon a
very extensive and influential portion of the community, by
the publication of a work which should embrace a judicious
selection of all those MACHINEs, ENGINES, MANIPULATIONS,
PROCEsses, and DISCover IEs, that now lie scattered through-
out several hundred volumes of the scientific journals, or are
inscribed in obsolete characters upon the rolls of the Court of
Chancery, in the form of specifications of patent inventions.
iv P}}}''FACE,
To accomplish an undertaking of such great convenience to
the scientific, as well as of real utility to operative men, in a
form adapted to instant reference and ready application, has
been my chief aim in the present work, which will com-
prehend, in addition to the usual matter contained in cyclo-
paedias on the mechanical and chemical sciences, upwards of
two thousand modern inventions and discoveries of merit and
originality, illustrated by Engravings carefully executed from
accurate working drawings.
Notwithstanding the extent and variety of subjects which
this work embraces, it may be necessary to remark, that by
the adoption of a small type, and close printing, the economy
of space is so far attained as to admit of each subject
receiving the consideration due to its importance, and to
comprise the whole in two thick octavo volumes. Thus, the
preparation and numerous manufactures of that invaluable
metal, the indispensable material of our machinery, (IRoN)
has received particular attention: so have, likewise, the
various manipulations and mechanism employed in our great
staple commodities, COTTON, SILK, wool,LEN, and LINEN.
The construction of ENGINEs (particularly STEAM ENGINEs),
MILLS, RAILWAYS, CARRIAGES, SHIPS, BOATS, DOCKS, CANALS,
BRIDGES, FURNACES, BOILERS, GAS MACHINERY, LOOMS,
PRESSES, PUMPs, PADDLES, PLOUGHS, STILLS, WATCHES,
CLOCKs, wATER-works, wher. Ls, CRANES, STOVEs, and a
thousand other subjects, receive, in like manner, their share
of attention. The various important processes of DYEING,
PISTILLING, BLEACHING, BREWING, TANNING, and numerous
other chemical manufactures, present also conspicuous
features in the contents of this work, the whole of which
may be said to combine an exposition of the entire series of
the Mechanical and Chemical Arts of the British Empire.
I,UKE HEBERT,
PATER Nost ER-Row,
November 1, 1835,
THE
E N G ſ N E E R'S A N D M E C H AN I C'S
ENCYCLOPAEDIA.
ABACA. A kind of flax, which grows in the Philippine Islands. There are
two varieties of it, the 'white and the grey; the former is used in the fabrication
of fine linen, and the latter chiefly for cordage.
ABACUS. An instrument employed to facilitate arithmetical calculations.
The name was given by the ancients to a table strewed with dust, on which their
mathematicians were in the practice of drawing their diagrams. Similar tables
are employed in our Lancasterian schools, for teaching children to write. The
abacus employed by the ancient Greeks for making calculations was, it is said,
similar to the “counting machine” sold in our toy and stationary shops, for
teaching the rudiments of arithmetic. It consists of twelve parallel wires, fixed
in a light rectangular frame, each wire carrying twelve beads, or balls. There
are thus 12 times 12, answering to the common multiplication table, all the
results of which it demonstrates to the dullest capacity; and by moving the
beads from one side to the other, the operations of addition or subtraction are
rendered clear and obvious to the juvenile student.
ABACUS. In architecture, the level, tile-shaped tablet, formed on the capital
of a column to support the horizontal entablature.
ABRASION. The act of tearing, or wearing away the surface of any sub-
stance by rubbing. See FRICTION.
ABSORB; from the Latin verb, absorbeo, signifying to suck in. When a
solid body combines with one that is fluid, and the compound remains solid, the
solid is said to have absorbed the fluid; and the solid in this case, likewise,
becomes an absorbent. In common language, we say, sugar absorbs water; but
this is not strictly correct, for in proportion as the water is taken up, the sugar
is dissolved. Sponge is, however, a perfect absorbent. In like manner liquids
absorb ariform matters; thus, water absorbs carbonic acid gas; charcoal, and
other porous solids of a fibrous texture, have the faculty of absorbing the gases
in a remarkable degree.
ABSORBING AND PRODUCTIVE CASCADE. An apparatus of great
utility and elegance, invented by M. Clement. It is known that the absorption
or solution of the gases takes place in proportion to the pressure on the absorbing
liquid, the extent of surface exposed to the absorbing action, and to the length
of time in which it is exposed. If the pressure, however, be very great, the
vessels are liable to rupture; and it therefore becomes an important object to
strengthen the influence of the other two principles just mentioned, which has
been obtained in a very eminent degree by the invention of M. Clement. In
this apparatus, which is represented in the annexed diagram, the gas has no
pressure to sustain, but the surfaces of its contact are exceedingly multiplied and
extcnded
2 ABSORBING AND PRODUCTIVE CASCADE.
The column a is filled with a great number of small bulbs of glass or porcelain,
its lower extremity resting in another cylinder b, of greater diameter, in which
is a cavity adapted to the reduced diameter of the column, which communicates
with two small tubes c, d, the former being employed to introduce the gas, and
º2.
iº
Af
º
:
the latter to discharge the liquid. At e is a reservoir of water, with a conducting
pipe f the supply therefrom being regulated by a cock g. The water, in its
passage to the lower part of the column, successively moistens all the small
spheres, and being thus impeded in its progress, a very considerable time is
occupied in its descent. On the other hand, the gas, as it is introduced, occu-
pying all the vacant interstices, becomes infinitely divided; and therefore as it can
only pass through the intermediate spaces very slowly, the duration of the contact
is much prolonged, and the absorption promoted. The inventor calculates that
the absorbing power of this apparatus is 322 times greater than the ordinary
simple vessels used for the purpose. Although M. Clement, in making this
comparison, has unquestionably selected the most unfavourable case, it must be
admitted that his absorbing cascade possesses great advantages. To the appa-
ratus thus described, M. Clement adapts another, which he calls “the Pro-
ductive Cascade,” shown in combination in our diagram. It is intended to
produce gas for a considerable period of time, and in a more convenient
and less expensive manner than by the ordinary methods. Suppose, for
example, it is required to prepare oxymuriatic acid or chlorine; a large vessel h,
provided with four openings, is filled with oxide of manganese, broken into large
pieces; the opening i is by a tube connected to a leaden vessel k, containing
common salt and sulphuric acid. By the tube l, a small stream of water is
made to flow from the reservoir above, which gradually moistens the whole
surface of the pieces of manganese, and permits the muriatic acid gas to attack


ACCELERATION. 3
and dissolve it very easily. The chlorine which is produced, passes by the tube
n, into the absorbing cascade, while the muriate of manganese is carried off as
it forms, by the water, through the tube o, into the reservoir p. By this arrange-
ment, there is no occasion to reduce the manganese to powder, and a much
larger quantity may be operated on at the same time, without the operator being
under the necessity of frequently renewing the charge of materials, and dis-
mounting his apparatus.
ABUTMENT, in Carpentry, means the joining or meeting of two pieces of
timber, of which the fibres of the one extend perpendicularly to the joint, and
those of the other parallel to it. See Nicholson's “Practical Builder.” In
Civil Architecture, the term is applied to that which receives the end of, and
gives support to, any thing having a tendency to spread or thrust outwards.
When the arches of a bridge are less than semicircles, or less than semi-ellipses,
the parts which they thrust or rest against, are termed abutments. If the arches
are complete semi-circles or semi-ellipses, or other formed arches that spring
from a vertical line, they are piers or imposts. The extremities of a bridge are,
however, always termed abutments; that is, abutments of the bridge itself, on
the ground, that the roadway may be considered an outer arch, whose abutments
are the land piers. The term abutment is likewise much used by engineers, to
express those fixed parts of mechanism from whence a resisting or reacting
force is obtained. Thus each of the ends of the cylinder of a reciprocating
steam engine form reacting points for the pressure of the steam, causing the
piston to be impelled the contrary way. In a rotary engine, the steam stop is
the abutment; in a screw-press, the stationary head through which the screw
passes, is also an abutment.
ACCELERATION is the increase of velocity in a moving body, caused
by the continued action of the motive force. When bodies in motion pass
through equal spaces in equal times, or, in other words, when the velocity of
the body is the same during the period that the body is in motion, it is termed
uniform motion, of which we have a familiar instance in the motion of the
hands of a clock over the face of it; but a more correct illustration is the
revolution of the earth on its axis. In the case of a body moving through
unequal spaces in equal times, or with a varying velocity, if the velocity
increase with the duration of the motion, it is termed accelerated motion; but
if it decrease with the duration of the motion, it is termed retarded motion. A
stone thrown up in the air, affords an illustration of both these cases, the motion
during the ascent being retarded by the force of gravity, and accelerated by the
same during the descent of the stone. All bodies have a tendency to preserve
their state, either of rest or of motion; so that if a body were set in motion, and
the moving force were withdrawn, the body, if unopposed by any force, would
continue to move with the same velocity it had acquired at the instant the
moving force was withdrawn. And if a body in motion be acted upon by a con-
stant force (as the force of gravity), the motion becomes accelerated, the velocity
increasing as the times, and the whole spacesº through increasing as the
square of the times; whilst the proportional spaces passed through during
equal portions of time, will be as the odd numbers, 1, 3, 5, 7, &c.; and the space
passed over in any portion of time, will be equal to half the velocity acquired at
the end of such time, which results will be better brought to view in the follow-
ing Table.
Times. Velocities. Spaces for each Time. Total Space.
1 1 1 1 - 12
2 2 3 3 + 1–4–22
3 3 5 5 + 3 + 1–9–3 *
4 4. 7 7+ 5 + 3 + 1=16=4?
It has been ascertained by experiment, that a body falling freely by its own
weight from a state of rest, will descend through 164 feet in the first second of
time, and will have acquired a velocity of . feet; but from the rapidity with
which the velocity increases, we cannot extend the experiment, for in only four
seconds, a body falling freely would pass through a space of 256 feet. But by
4. ACCELERATION.
an ingenious contrivance of the late Mr. Attwood, of Cambridge, the laws of
motion above laid down may be verified experimentally. The machine is called
“Attwood's machine,” after the name
of the inventor; and the principle of its
action consists in counteracting a portion
of the gravitating power of a body, by
the gravitating power of a smaller body;
so that the absolute velocity, and the
spaces passed through, shall be less than
in the case of bodies descending freely,
whilst, as the force is constant, the same
ratio of progression will hold in both
cases. The annexed figure represents one
of these machines, as constructed by Mr.
Toplis, a a a is a triangular frame, upon
three moveable legs; b, a small platform
suspended from it by a universal joint
c c, and supporting two upright standards
d d, in which the axis of a light brass
wheel e revolves with very little friction.
Over a groove in the periphery of the
wheel, passes a very light and pliable
silk thread, from the ends of which hang
two equal weights f, g. Into the under
side of b is screwed a square rod h,
descending to the floor, to which it is
secured, in a perpendicular position, by
small pins passing through holes in the
claws at # 7. On the face of the rod is a
scale of inches. k is a brass guide, fixed
at the upper part of the rod h, so that
when the top of the weight g touches the
lower side of k, the under side of g is on
a level with the top, or commencement
of the scale; l is a small stage, movable
along the rod h, and having a hole in it
sufficiently large for the weight g to pass:
on one side is a tightening screw m. n
is another movable stage, fitted with a
tightening screw o, as also a fork p,
turning upon a hinge. The experiments
are conducted as follows:—A small cir-
cular weight is placed upon g, which is
pulled up to the top of the scale, and the
stage n is screwed to the rod h, on a level
with the lower part of the weight f, which
is held down upon it by the fork p. Upon
releasing f from the fork, the weight g
descends with a slow, but gradually acce-
lerated motion, and the number of inches
the weight has descended, at each suc-
cessive beat of a pendulum (suspended
from another triangle) is observed upon ||
the scale; and if the additional weight tº
be such as to cause g to descend through ºff
three inches in the first second, then it
will cause it to descend through i foot in
two seconds, and through 63 feet in five
seconds. If the additional weight be

ACI DS. 5
removed, and a small bar of equal weight, but of a length exceeding the diameter
of the hole in l, be placed upon g, and the stage l be set at any division of the
scale, at which the weight would arrive at the end of any number of seconds,
the stage will intercept the bar in its descent, and the weight will continue to
descend with the velocity it had acquired upon reaching l. Thus if the velocity
at the end of the second second be two feet, in which case the weight would
have descended one foot in that time, if the stage be set at one foot upon the
scale, it will intercept the bar at the end of the second second, and the weight
g will move with a uniform velocity of two feet per second, through the remaining
portion of its descent. If it is required to illustrate the case of retarded motion,
the small circular weight is placed upon the weight g, and a similar small weight
upon the weight f, so that g, still outweighing f will descend; but as soon as
the stage l intercepts the bar with the small weight upon it, f becomes the
heaviest, and g will descend with a velocity decreasing as the squares of the
times, counted from the time of g passing the stage l. To diminish as much as
possible the friction of the axis of the wheele, which carries the line from which
the weights hang, Mr. Attwood, instead of causing the axis to turn in fixed
bearings, supported it upon the peripheries of four anti-friction wheels, fixed
upon the ends of two spindles placed parallel to each other, and as close together
as the diameters of the wheels would allow. The sliding or rubbing motion of
the axis of the wheel e, is by this means transferred to the spindles of the anti-
friction wheels, (for the axis does not slide, but it rolls over their peripheries,)
and the amount of the friction becomes diminished in the proportion of the dia-
meter of the axis of the wheel e, to the diameter of the anti-friction wheels. This is
an extremely beautiful and effectual arrangement, but requires great care and
nicety of execution; it also enhances greatly the cost of the instrument. Mr. Top-
lis's method of supporting the axis of the wheel is less complex and costly, whilst
it is attended with very little friction, owing to the extremely small quantity of
rubbing surface. His plan is as follows: the axis consists of a short piece of steel,
not equal in length to the distance between the two standards, between which it is
supported. In each end of the axis a conical recess is formed, terminated by a short
cylindrical one; these conical recesses receive the ends of two studs or pivots,
supported by the vertical standards, and formed into cones more acute than the
conical recesses. By this means the rubbing surfaces are reduced to a mere Iine,
forming a species of knife-edge support; the axis is kept steady by the different
obliquities of the external and internal cone; and the end of the pivot cannot
wear down, as it does not reach the bottom of the cylindrical part of the recess.
For the sake of portability, the legs of the triangle, and the square rod h, are
jointed in the middle, and the wheel, stages, &c. can be packed separately in a
small case. Altogether we think Mr. Toplis has rendered the instrument much
more portable, and less liable to injury, whilst he has very much diminished the
cost without impairing its efficiency.
ACERIC ACID. A peculiar acid, said to exist in the juice of the maple.
It is decomposed by heat, like the other vegetable acids.
ACETATES. The salts formed by the combination of the acetic acid with
alkalies, earths, and metallic oxides. See their different bases, and the article,
Acid, AcET1c.
ACETIC ACID. See Acid, Acetic.
ACHROMATIC. A term applied to those lenses of telescopes, and other
optical instruments, in which the aberrations of light common to ordinary lenses
are remedied, and the colours justly reflected.
ACIDS. A most important class of chemical compounds, which have for the
most part the following properties. They have a sour, or sourish taste, the
stronger kinds being acrid and corrosive. They change the vegetable blues and
purples to a bright red. They unite with water in almost every proportion.
With a few exceptions, they are decomposed or volatilized by a moderate heat.
They combine with all the alkalies, and most of the metallic earths and oxides,
and form with them that class of bodies termed salts. The varieties of acids
are extremely numerous, and will be generally noticed under the head CHEMISTRY.
The four principal acids of commerce, viz. the acetic, suphuric, nitric, and
B
6 A CID–ACETIC
muriatic, which are manufactured on the great scale, we shall describe in this
lace.
ACID, AcETIC, is the acid contained in common vinegar, but in a very dilute
state, and in combination with other vegetable principles. It is found united
with potash in a great variety of plants, also in several animal secretions. It
is likewise the result of a spontaneous fermentation, to which liquid, vegetable,
and animal matters, are liable. Strong acid, as the sulphuric and nitric, develop
the acetic, by their action on vegetables. Dry vegetable substances generally,
when subjected to a red heat in close vessels, yield it copiously. The proportion
of the products varies not only from employing different substances, but they are
different when only one substance is employed, according as the heat is greater
or less, or the operation is differently managed. When a vegetable substance is
distilled in close vessels, at first the water comes over which existed ready formed,
and then water formed by union of the oxygen and hydrogen of the substance.
Afterwards, a quantity of carbon is separated; and by the continued application
of heat, this unites with the oxygen and hydrogen, and forms an acid, formerly
supposed to be a particular acid, and then called pyroligneous acid, but it is now
known to be the acetic acid, united with empyreumatic oil, which rises somewhat
brown, and grows thicker and darker, augmenting in density as the quantity of
carbon increases. At the same time, a small quantity of carbonic acid gas, much
carburetted hydrogen, and towards the close, a great quantity of gaseous oxide
of carbon, are disengaged. All the carbon not carried off in these various forms,
remains in the still, and generally preserves the form of the vegetable substance
employed. Since we have i. the nature of all these products, the process
has been much improved, and particularly by charring the wood, and by turning
the other products to advantage. In the forests, the wood is first charred, so as
to dissipate all the water of vegetation. t is, then introduced into a large cir.
cular vessel a, made of iron plates rivetted together, and having at its upper
part a small lateral iron cylinder; an iron cover is closely fitted to this pot,
and then it is lifted by means of a crane, or other mechanical power, and placed
in a cast iron retort c, set over a furnace of the same shape. The furnace is
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then covered with a lid e, constructed in masonry. A moderate heat being
applied to the furnace, at first the vapour of the wood is dissipated, but this
vapour soon ceases to be transparent, and becomes sooty. At this time a


ACID—ACETIC. 7
tube or cylinder, enclosed in another of brick-work or tiles, is affixed to the
lateral cylinder, and forms the coſidensing apparatus. This is differeniin different
places: in some, the condensation is effected by the air, the vapour being made
to pass through a long extent of cylinders, and sometimes of casks, adapted to
each other; but most generally the condensation or cooling is effected by water,
when it can be procured in sufficient quantities. The most simple apparatus for
this purpose consists of two cylinders ff, enclosed one within the other, and
having between them a space sufficient to allow a large quantity of water to flow
backwards and forwards, and thus cool the vapour. These cylinders are adapted
to the distilling apparatus, and placed inclined to the horizon. To this first
apparatus a second, and sometimes a third is adapted, and placed in a zig-zag
form, in order to occupy as little space as possible. The water is made to cir-
culate in the following manner. At the lower extremity g, of the condensing
apparatus, there is a tube which ought to be somewhat higher than the upper
part of the whole of this apparatus, where at h there is another short tube
curved towards the ground. Water from a reservoir is made to run through the
perpendicular tube to the lower part of the condensing apparatus, and fills all
the space between the cylinders. When the operation is going on, as the vapours
are condensed, they raise the temperature of the water, which becoming lighter
in consequence, flows out of the curved tube h. The condensing apparatus
terminates in a covered brick canal i, underground, at the end of which is a bent
tube k, that conducts the liquid products into the first cistern; when this is full,
it discharges itself by means of a syphon into a large reservoir; the tube which
terminates the canal, plunges into the liquid, and thus cuts off the communication
with the interior of the apparatus. The gas hereby disengaged, is conveyed by
means of the tube ll, under the ash-hole of the furnace. This tube is furnished
with a cock, to regulate the flow of the gas, and cut off the communication at
pleasure. That end of the tube which terminates in the ash-hole, rises a few
inches perpendicularly, and is furnished at its extremity with a perforated rose,
for distributing the gas uniformly under the vessel, without being itself liable to
become choked with the ashes, or to obstruct the feeding of the fire. The
degree of heat necessary to effect carbonization is not very great, yet, towards
the end of the process it must be raised sufficiently to make the vessel red-hot,
and the length of the operation is necessarily regulated by the quantity of wood
to be carbonized at the time. By the colour of the gas flame it is ascertained
when the carbonization is complete; at first it is of a reddish yellow colour, but
afterwards it becomes blue, as it throws off more oxide of carbon than carbu-
retted hydrogen; at last it becomes entirely white, probably caused by the
vessel being hottest at this period, and the combustion, therefore, may then be
considered as quite finished. There is also another method of ascertaining the
completion of the operation, which is more frequently had recourse to; that is,
the cooling of the upper part of the tubes, which is not surrounded with water;
some drops of water are then thrown upon it, and if these evaporate without
noise, the operation is considered to be finished. The adapting short tube is
next removed from the vessel, and the opening into it immediately closed by an
tron-plate cover, which is then luted with loam. The lid which covers the fur-
nace is next removed, and then the vessel itself is lifted out of the furnace by
means of the crane, which should be immediately replaced by another similar
retort got ready for the purpose.W hen the retort which has been taken out
has become cold, it is uncovered, and the charcoal taken out. Whatever may
be the kinds of wood employed in this operation, nearly the same results are
obtained, as far as respects the acid; not so, however, with regard to the char-
coal. The denser the wood, the better the charcoal; and it has been remarked,
that when the wood has been long left in contact with the open air, the charcoal
produced from it is of a much worse quality than from that wood which is car-
bonized the same year it was cut. A more simplified arrangement of apparatus
than the foregoing, employed for this purpose by an eminent manufacturer in
Glasgow, is described by Dr. Ure, in his Chemical Dictionary. . It consists of a
series of cast-iron cylinders, about 4 feet diameter, and 6 feet long, which are
built horizontally in brick-work, so that the flame of one furnace may play
8 ACID—ACETIC.
an ound two cylinders. Both ends are made to project a little from the brick-
work. One of them is provided with a disk of cast-iron accurately fitted to it,
and from the centre of this proceeds a tube about 6 inches in diameter, that
enters the main tube of refrigeration. The diameter of this tube may be from
9 to 14 inches, which will vary according to the number of cylinders. The other
end of the cylinder, which is called the mouth of the retort, is closed by a disk
of iron, smeared round its edges with clay lute, and made fast by means of
wedges. The charge of wood for a cylinder of the before-mentioned dimensions,
is about 8 cwt. The hard woods, oak, ash, birch, and beech, are alone used.
fir does not answer. The heat is kept up during the day-time, and the furnace
is allowed to cool during the night. Next morning the door is opened, the
charcoal removed, and a new charge of wood introduced. The average product
of crude vinegar, called pyroligneous acid, is 35 gallons. It is much contami-
nated with tar, is of a deep brown colour, and has a specific gravity of 1.025.
Its total weight is therefore about 300 lbs. The residuary charcoal is found to
weigh no more than one-fifth of the wood employed. Hence nearly one-half of
the ponderable matter of the wood is dissipated in incondensible gases. The crude
pyroligneous acid is rectified by a second distillation in a copper still, in the
body of which about 20 gallons of viscid tarry matter are left from every 100.
It has now become a transparent brown vinegar, having a considerable empy-
reumatic smell, and a specific gravity of 1.013. Its acid powers are superior
to those of the best household vinegar in the proportion of 3 to 2. By re-
distillation, saturation with quicklime, evaporation of the liquid acetate to dryness,
and gentle torrefaction, the empyreumatic matter is so completely dissipated,
that on decomposing the calcareous salt by sulphuric acid, a pure, perfectly
colourless, and grateful vinegar rises in distillation. Its strength will be in pro-
portion to the concentration of the decomposing acid. It is a common error to
regard the production of vinegar from the distillation of wood as a recent dis-
covery. In the Miraculum Mundi of Glauber (who has given his name to a
well-known description of salts), he says, “If this juice of wood be rectified, it
may be used in the preparation of good medicines; in mechanic arts; in the
making of many fair colours from the extraction of metals, minerals, and stones;
and for all things for which common vinegar is used; yea, far more commo-
diously, because it much exceedeth common wine and beer vinegar in sharpness.”
Glauber mentions some other applications of the acid which have yet to find
their way into modern practice. “If hop-poles,” he says, “be dipped in the
oil, it not only preserves them, but fattens the plant; and as insects abhor these
hot oils, if they be applied to the bark of fruit trees, it will defend them from
spiders, ants, canker-worms, and other insects; by this means, also, rats and
mice may be prevented from creeping up hovel posts and devouring the grain l’”
An acetic acid of very considerable strength may also be prepared by saturating
perfectly dry charcoal with common vinegar, and then distilling. The water
easily comes off, and is separated at first, but a stronger heat is required to expel
the acid. If vinegar be exposed to very cold air, or to a freezing moisture, its
water will be separated in the form of ice, and the interstices be filled with a
strong acetic acid, which may be collected by draining. The radical vinegar of
the apothecaries, made by dissolving in it a little camphor, or fragrant essential
oil, has a specific gravity of about 1,070, and consists of one part of water to
two of the crystallized acid. The pungent smelling salt is made by moistening
the sulphate of potash with a little concentrated acetic acid. Acetic acid acts
upon iron, zinc, copper, and nickel, in the metallic state, and upon the oxides
of various other metals; its combination with the latter being usually effected
by mixing a solution of their sulphates, with that of an acetate of lead. It has
a very slight action upon metallic tin, when highly concentrated. The strongest
acetic acid will, we are informed, dissolve metallic lead, which is contrary to the
statements of chemical authors. Acetic acid dissolves resins, gum-resins, cam-
phor, and essential oils. Its odour is employed in medicine to relieve nervous
headache, fainting, and sickness from crowded rooms. Its anti-contagious
powers are not now so confidently relied upon as formerly. It is extensively
used in calico printing. It unites with all the alkalics, and most of the earths,
ACID–MURIATIC. Q
and with these bases it forms compounds, some of which are crystallizable, and
others have not yet been reduced to a regularity of figure. For the properties
and uses of these combinations we refer the reader to Dr. Ure's Dictionary of
Chemistry. .
ACID, MURIAtic, may be obtained by distillation from a mixture of com-
mon salt with clay or bole, which is the original process; but it is now only
used where fuel and pottery earths are cheap, and oil of vitriol dear. The
method most commonly practised at present to obtain it, is to decompose the
muriate of soda, or common salt, by sulphuric acid, and condensing the
muriatic acid gas in water, for which it has a great affinity. The annexed en-
gravings represent the most approved apparatus for this purpose.
Fig. 1.
#ilºſſ;|lº.
ºwn...ſº
! ſ in
|ji: Tºm
I ig, 1 is a transverse, and Fig. 2 a longitudinal section of a bench of cast-
iron retorts a, (generally twenty in number,) resembling those used in gas works.
They are placed in pairs, each pair having a separate fire-place e, grate f. and
ash-pit g. Every part of the cylinder should be equally heated, that the decom-
position of the salt may be simultaneous, and the iron be as little as possible
injured by the acid. For this purpose, a plate of cast-iron k, is placed between
the cylinders; and the flues h are constructed so as to produce an equal draught
throughout every part of the furnace. The cylinders are closed at each end by
a plate of cast-iron luted into the rim of the cylinder. Each end plate has a
handle b, of cast-iron, and a small tube m, projecting from the upper part of the
plate, for the purpose at one end of pouring in the sulphuric acid, and of con-
veying away the products at the other. The first cylinder communicates by the
bent glass pipe c, with the earthen vessel d, which has three mouths, and which
again communicates by two other bent tubes c, with two similar vessels. All the
gas not condensed in the first bottle d, passes into the other bottle d'; at the
same time th second bottle d receives the gas from the second cylinder, and
transmits the gas which it does not condense to a third bottle, and so on to the
last bottle, which receives the gas not condensed in all the others, as also the












10 ACID—SULPHURIC.
gas from the last cylinder. From this bottle whatever gas is not condensed, is
transmitted through a second range of bottles half filled with water, which will
absorb two-fifths of its weight of muriatic acid; and in this second range the
whole of the gas is condensed. The first range, it should be observed, is placed
in a trough l, through which is maintained a current of cold water. The purest
acid is obtained in the second range of bottles; that which is condensed in the
first range containing always a little sulphuric acid, and sometimes sulphate of
soda and muriate of iron. Each cylinder is charged with about 160lbs. of com-
mon salt, and the end is luted with clay, and the fire is kindled; 128lbs. of sul-
phuric acid at 669, Baumé's areometer, are then poured on the salt. After the
gas ceases to come over, the end plate is taken off, the sulphate of soda removed,
and the operation repeated: thus 130lbs. of muriatic acid, of the spec. grav. 1.190,
may be obtained from 100lbs. of salt. Muriatic acid, mixed with nitric acid,
forms aqua regia, which is a solvent for gold and platinum : it is also used to
prepare muriate of tin for dyers, to scour metals, and numerous other purposes.
ACID, NITRic, may be made in various ways, but that most commonly
employed, is to decompose saltpetre, or nitrate of potash, by concentrated
sulphuric acid, in an apparatus similar to that used in the preparation of mu-
riatic acid, except that four cylinders are usually heated by one fire. The
cylinders communicate by tubes with three or four rows of earthen vessels,
the two first of which are plunged in water. The tubes which proceed from
the cylinders must be of glass, that the colour of the gas which passes may be
seen, as it shews the progress of the operation; the other tubes may be of
earthenware. Each cylinder is charged with 170lbs. of nitrate of potash, and
100lbs. of sulphuric acid, of 1.845 spec. grav. The heat must be equally applied,
and the fire conducted slowly. As the operation advances, the vapours become
red; and it is finished when these vapours are no longer visible : a brisk fire is
made towards the close to disengage all the gas. The acid condensed in the first
row of bottles is always the least pure: that contained in the second range and
in part of the third contains only nitrous acid; this is disengaged by carrying it
to ebullition in glass retorts; the ebullition is gradually stopped when it becomes
white, and it is in this state sold in commerce. All the weak acid in the last
vessels is again put into the first or second range instead of pure water, and water
is always put in the last row to complete the condensation. The acid thus ob-
tained is not sufficiently pure for all purposes for which it is wanted, but requires
to be distilled in glass retorts, taking care to separate the products. The first
portions which are volatilized are chlorine and nitrous acid; these are separated
when the liquor in the retorts becomes white, after which the pure nitric acid
comes over. The distillation should be stopped when nine-tenths of the acid in
the retort is volatilized. Nitric acid is employed in the manufacture of sulphuric,
oxalic, and other acids, in the composition of aqua regia, in making the red pre-
cipitate, in dying, gilding, assaying money, in parting gold, and numerous other
processes.
ACID, SULPHURIC, is obtained either by simple distillation from copperas,
(which was the original method,) or by the combustion of sulphur, in large
leaden chambers, in combination with substances yielding a large supply of
oxygen, which is the method generally practised at the present day. The latter
process is conducted in various ways; the most usual method in this country is
the following. Common brimstone, coarsely ground, is mixed with saltpetre, in
the proportion of 8 lbs. of the former to 1 lb. of the latter; the mixture is spread
upon iron plates set upon stands of lead, in a large chamber, lined with lead, and
covered at the bottom with a thin sheet of water. The materials are ignited by
means of a hot iron, and the door is closed. The sulphur in vapour then com-
bining with the oxygen of the nitre, forms sulphuric acid, and condenses in the
water, which is afterwards drawn off and concentrated, first in leaden vessels,
and then in glass retorts, (which are sometimes lined internally with platinum);
but some manufacturers dispense with the leaden boilers altogether. In some
of the more recently established manufactories in France, the following process
has been employed with very advantageous results:—The sulphur is burned upon
an iron plate, set over a furnace, beneath a leaden cylinder, opening into a
ACID–SULPHURIC. 1 1
leaden chamber, containing about 20,000 cubic feet : at the same time, a retort
placed in a said bath, aſid eviliaiuing 93 ibs. of nitric acid, and 141b, of molasses,
is heated, the nitrous gas disengaged being conducted into the leaden cylinder
about 2 feet above the burning sulphur, and this operation being continued
until all the nitrous gas is disengaged. From the residue in the retort oxalic
acid is obtained. About two hours after the combustion has commenced, steam
is admitted into the chamber by a pipe, which enters about the middle of the
chamber. Soon after the introduction of the steam, a condensation is perceived
in the chamber, and a small hole is opened to admit a supply of atmospheric
air. When the condensation is completed, which is commonly in about three
hours' time from the commencement of the operation, a door in the cylinder,
and two valves placed under a tall chimney, are opened, in order to renew the
air in the chamber, after which the operation may be repeated. The bottom
of the chamber should always be covered with liquid, and it is inclined to the
horizon, so that the liquid may be 9 inches deep at one end, and only 13 at
the other, and only the overplus is drawn off daily. The acid may be concen-
trated in the chambers to about 1.450 spec. grav.; after which it is removed
to leaden boilers, and brought to a spec. grav. of 1,600 ; the remaining
requisite concentration is effected in glass and platinum retorts. A quantity
of acid comes over during the evaporation, which is condensed by a leaden
worm fixed to the neck of the retort. The annexed cut represents the apparatus
employed in this process.
~~~~~~~~~~~~~
É====== ---Tº-E E = E−. º
SSNs §
Ş §
a is a portion of the chamber lined with lead; b, the leaden cylinder entering
the chamber at one end of it, and rising about 10 inches above the floor c.
The cylinder at its lower part d, turns inwards and upwards, forming a gutter
e, concentric with the cylinder; in this gutter a portion of weak acid is always
kept up as high as the line g, to prevent the lead from getting too much heated.
The whole is placed on a mass of brick-work h, in the middle of which there is
an iron dish k, having a convex bottom, and a rim 3 inches high; it is mounted
over a furnace l. m is a door in the leaden cylinder, and n, an air-hole in the
door, fitted with a stopper; r, a glass mattress, containing the nitric acid and
molasses; s, the steam boiler; t, the steam pipe. Sulphuric acid is very exten-
tively used in the chemical arts, particularly in bleaching, and some of the processes

12 ADHESION.
of dying; in the manufacture of the nitric and muriatic acids, and in numerous
other branches of manufacture. The combinations of this acid with various
bases, are called sulphates, many of which are of great utility in medicine and
the arts. The acidulous sulphate of alumina, combined with potash or ammonia,
forms the important article called ALUM, which see.
ACRE. A measure of land, amounting to 4 square roods, or 160 square
poles or perches. The English statute acre is about 3 roods and 6 falls standard
measure of Scotland. The Welsh acre contains commonly 2 English ones. The
Irish acre is equal to 1 acre 2 roods and 19; perches English. The number
of acres in England, according to Dr. Grew, amounts to 46,080,000.
ADAMANT. The ancient name of the diamond. This term is also sometimes
applied to the scoriae of gold, and to a species of iron ore.
ADAMANTINE SPAR. There are two varieties of this important mineral
known in Europe, one of which is brought from China, the other from India.
They are both remarkable for their extreme hardness, which approaches to that
of the diamond, and is therefore used in polishing gems and steel. In India,
corundum powder is formed into a paste with lac resin, and moulded into grind-
stones of a very durable nature.
ADHESION denotes an union, to a certain degree, between two distinct
substances, and differs from cohesion, (with which the former word is often con-
founded,) inasmuch, as the latter term is alone properly applicable to the retaining
together of the component particles of the same mass. Adhesion is, however,
of two kinds; the one, a species of natural attraction, which takes place between
the surfaces of bodies, whether similar or dissimilar, and which, in a certain
degree, connects them together; the other, the joining or fastening together of
two or more bodies, by the application of external force. With respect to the
first-mentioned, it has been proved, that the power of adhesion is proportionate
to the number of touching points; and this, in solid bodies, depends upon the
degree in which their surfaces are polished and compressed. The effects of this
{..". are extremely curious, and in many instances astonishing. It is stated
y Musschenbroëk, that two cylinders of glass, of rather less than 2 inches
diameter, being heated to the temperature of boiling water, and brought into
contact with melted tallow between their surfaces, required a force of 130 pounds
to separate them; pieces of lead, of the same area of surface, required 275
pounds; and soft iron, 300 pounds. The experiments made and described by
Mr. Martin, in the Philosophia Britannica, make the force of this kind of
adhesion much greater than Musschenbroëk. He took two leaden balls, and
having carefully scraped off, with the edge of a sharp pen-knife, so much of
their spherical surfaces as to form two planes of one-thirtieth of an inch in
area, he pressed them together forcibly, and with a gentle turn of the hand.
The adhesion of these small surfaces was such, that he lifted, with the balls so
united, above 150 pounds weight. The adhesion between two brass planes 44
inches in diameter, with grease smeared over their surfaces, was such, that he
could never meet with two men strong enough to separate them by pulling
against each other. The editor of this work had put into his hand many years
ago, two brass plates, of about 2 inches diameter, having their surfaces so per-
fectly flat, that, without any interposing matter, he could only separate them by
sliding them edgeways. With respect to the second-mentioned kind of adhesion,
some useful experiments were made by Mr. B. Bevan, on the adhesive force of
iron nails, screws, and pins; also of the common cements, glue, and sealing-
wax, which that gentleman communicated to the editor of the London Mecha-
nics' Magazine. The following is a condensed account of them :—
ADHEsion of IRoN NAILs, in which Mr. Bevan's object was to determine,
first, the adhesive force of different kinds of nails, when driven into wood of
different species: second, the actual weight, without impulse, necessary to force
a nail a given depth: third, the force requisite to extract a nail when so driven.
Mr. Bevan observes, that the theoretical investigation points out an inequality
of resistance to the entrance and extraction of a nail, supposing the thickness
to be invariable; but as the general shape of nails is tapering towards their
points, the resistance of evtrance necessarily becomes greater than that of
ADHESHON. | 3
extraction; in some experiments he found the ratio to be about 6 to 5. The
fellowing Table exhibits the relative adhesion of nails of waiious kinds when
driven into dry Christiana deal, at right angles to the grain of the wood.

Number Inches Pounds .
Description of Nails used. to the lb. Inches long. forced into required to
avoirdupois. the wood. | extract.
Fine sprigs . . . . . . . . . . . . . 4560 0.44 0.40 22
Ditto . . . . . . . . . . . . . . . 3200 0.53 0.44 37
Threepenny brads . . . . . . . . 618 1.25 0.50 58
Cast-iron nails . . . . . . . . . . 380 1.00 0.50 72
Sixpenny nails . . . . . . . . . . 73 2.50 1.00 187
Ditto . . . . . . . . . . . . . . . tº e - © 1.50 327
Ditto . . . . . . . . . . . . . . . tº gº - - 2.00 530
Fivepenny nails . . . . . . . . • - 139 2.00 1.50 320
–
The percussive force required to drive the common sixpenny nail to the depth
of 1% inch into dry Christiana deal, with a cast-iron weight of 6.275 lbs.
was four blows or strokes falling freely the space of 12 inches; and the steady
pressure to produce the same effect, was 400 lbs. A sixpenny nail driven
into dry elm, to the depth of one inch across the grain, required a pressure
of 327 lbs. to extract it; and the same nail driven end-ways or longitudinally
into the same wood, was extracted with a force of 257 lbs. The same nail
driven 2 inches end-ways into dry Christiana deal, was drawn by a force of
257 lbs. ; and to draw out 1 inch, under like circumstances, took 87 lbs. only.
The relative adhesion, therefore, in the same wood, when driven transversely
and longitudinally, is 100 to 78, or about 4 to 3 in dry elm, and 100 to 46, or
about 2 to 1 in deal; and in like circumstances, the relative adhesion to elm
and deal is as 2 or 3 to 1. The progressive depths of a sixpenny nail into dry
Christiana deal, by simple pressure, were as follows:—
One quarter of an inch, a pressure of . . . . . 24 lbs.
Half an inch . . . . . . . . . . . . . . . . . . 76 —-
One inch . . . . . . . . . . . & s a e s e s tº e 235 —
One inch and a-half . . . . . . . . . . . . . . 400 —
Two inches . . . . . . . . . . & © tº e º e º e s 610 —
In the above experiments, great care was taken by Mr. Bevan to apply the
weights steadily, and towards the conclusion of each experiment, the additions
did not exceed 10 lbs. at one time, with a moderate interval between, generally
about one minute, sometimes ten or twenty minutes. In other species of wood,
the requisite force to extract the nail was different. Thus, to extract a common
sixpenny nail, from a depth of one inch, out of
Dry oak, required . . . . . . . . . . . . . . . 507 lbs.
Dry beech . . . . . . . . . . . . . . . . . . . . 667 —
Green sycamore . . . . . Q e º e s gº º e º ºs e 312 —
From these experiments, we may infer that a common sixpenny mail driven
two inches into dry oak, would require a force of more than half aton to extract
it by a steady force.
ADHEsion of IRoN PINs. The force necessary to break or tear out a half-inch
iron pin, applied in the manner of a pin to a tenon in the mortice, has likewise
obtained the attention of the same celebrated experimentalist. The thickness
of the board was 0.87 inch, and the distance of the centre of the hole from the
end of the board, 1.05 inch. The force required was 976 lbs. As the strength
of a tenon from the pin-hole may be considered in proportion to the distance
from the end, and also as the thickness, we may, for this species of wood, obtain
the breaking force in pounds nearly, by multiplying together one thousand times
the distance of the hole from the end, by the thickness of the tenon in inches.
ADHEsion of GLUE. Mr. Bevan glued together by the ends, two cylinder,
of dry ash wood, one-fifth of an inch in diameter, and about 8 inches long
C
14 AEOLIPILE.
After they had been glued together twenty-four hours, they required a force of
1260 lbs, to separate them; and as the area of the circular ends of the cylinders
were 1.76inch, it follows that the force of 715 lbs. would be required to separate
one square inch. It is proper to observe, that the glue used in this experiment
was newly made, and the season very dry; for in some former experiments on
this substance, made in the winter season, and upon some glue which had been
frequently made, with occasional additions of glue and water, he obtained a
result of 350 to 500 lbs. to the square inch. The present experiment was, how-
ever, conducted upon a larger scale, and with care in the direction of the resultant
force, so that it might be, as near as practicable, in a line passing at right angles
through the centre of the surfaces in contact. The pressure was gradually
applied, and was sustained two or three minutes before the separation took place.
Upon examining the separated surfaces, the glue appeared to be very thin, and
did not entirely cover the wood, so that the actual adhesion of glue must be
something greater than 715 lbs. to the square inch. Upon comparing with this,
the natural cohesive force laterally of wood of the same kind, Mr. Bevan found
it to be only 562 lbs. : consequently, if two pieces of this wood were well glued
together, the wood would have yielded in its substance before the glue. From
a subsequent experiment made on solid glue, the cohesive force was found to be
4,000lbs. per square inch; from which it may be inferred, that the application
of this substance as a cement is susceptible of improvement.
ADHEsion of SEALING WAx: The best red sealing wax was proved to have
a cohesive force equal to 1500 lbs, per square inch, and the black sealing wax
was rather more than 1,000 lbs. to the square inch; the deficiency in the latter,
we suppose, was owing to the diminished quantity of lac resin used in the
composition.
ADIT, in Mining, is a subterraneous º slightly inclined, about 6 feet
high, and 2 or 3 feet wide, begun at the bottom of a neighbouring valley, and
continued up to the vein, for the purpose of carrying out the minerals and
drawing off the water.
AEOLIAN HARP, or harp of AEolus, is a musical instrument, which pro-
bably received its name from the effects produced upon it by the air without
human aid. It consists of a slight box of fibrous wood, usually deal, containing
a low bridge at each end, over which is stretched, upon pegs, a series of fine
cat-gut strings, generally about fifteen in number, which being of equal size
and length, are therefore unisons. Its length should correspond with the size
of the window or other aperture where it may be placed; its width need not be
more than from 4 to 6 inches, and in depth from 3 to 4 inches. It should be
placed between the lower sash and sill of a window, with its strings uppermost,
under which is a circular opening, as in the belly of the guitar. When the
wind blows athwart the strings, it produces the effect of a choir of music in the
air, swelling or diminishing its sounds according to the strength or weakness of
the blast. Mr. Crossthwaite has simplified this instrument by dispensing with
the sounding-board, and making it simply of two deal boards, with the strings
extended between them. Father Kircher being the first European author who
described it, the invention has been attributed to him; but the learned Mr.
Richardson, in his Dissertation on the Languages and Manners of the East, says,
that an instrument of the kind had been long in use in the East, before the time
of Kircher.
AEOLIPILE. A name that has been given to an instrument variously
modified, for converting in a close vessel water into steam. The first individual
who used it, appears to have been Hero the elder, a Grecian mechanic, who
settled in Alexandria about 130 years prior to the christian era, whose ingenuity
and talents being fostered by the Egyptian monarch, was the probable cause of
his interesting discoveries being handed down to us in his work entitled Spiri-
talia, or Pneumatica. Although in the state that he has presented it to us in his
aeolipile, it cannot be regarded as one of his most useful inventions, (his foun-
tain for raising water by compressed air possessing far more intrinsic merit,)
still as being the earliest germ of that great mechanic power, which seems
destined to change the face of the entire civilized world, it is well deserving of
AERATED WAT'ERS. 15
a description in this place, which we shall give, with reference to the subjoined
figure. Over a small furnace was # ==;
placed a vase or caldron a, containing :
water, from the cover of which pro-
ceeded two arms b c, forming the axis
of a hollow globe d. The arm b, is a
steam pipe, the other arm c, is solid,
having its extremity formed into a
conical pivot. At right angles to the
axis of the hollow globe, there proceeds
from it two tubes e e, bent at their ex-
tremities, which form the outlets of the # a
steam. Heat being applied to the cal- liſi–
dron, raises the steam, which flowing F=####,
through the tubular axis b, enters the \tilda'ſ frºſſ)
globe; thence the steam finds its way ilālū W
through the tubes e e into the atmo-
sphere, the reaction of the latter pro-
ducing a rotatory motion of the globe,
the velocity of which will depend upon
the strength of the steam.
AERATED WATERS. This term being popularly applied to a variety of
acidulous and alkaline beverages more or less impregnated with fixed air, or
carbonic acid gas, we introduce our article on the subject in this place ; and as
the manufacture of these liquids has of late years become of considerable extent,
owing to their agreeable as well as medicinal properties, we purpose describing
several ingenious apparatuses that have been used, or are still employed, for the
purpose. Water absorbs under the natural pressure of the atmosphere about
its own bulk or volume of carbonic acid gas. If a pressure be applied equal to
two atmospheres, the water will absorb double its own volume, its absorbing
power increasing as the pressure. Water thus impregnated acquires a pleasant
acid taste, to which is usually added a small quantity of potash or soda, and
such flavouring or other ingredients as may be required to imitate the natural
mineral waters. Nooth's apparatus was one of the earliest contrivances, and is
adapted to the preparation of small quantities of aerated
water. It is represented in the subjoined cut, and
consists of three vessels; the lowest a, is flat and
broad. So as to form a good basis; in this is put a quan-
tity of chalk or pounded marble, and some dilute
muriatic or other acid is introduced through a screwed
stopper b. The gas being thus generated, passes
through the tube c, in which a glass valve opens up-
wards into d, which contains the water or solution to
be impregnated, and is provided with a stop-cock to
draw off the liquid. The tube of the uppermost
vessel e, dips into d, occasioning therein some pressure;
and the gas which is not absorbed in the latter, passes
up into e, which being provided with a heavy stopper,
acts as a valve, and causes a considerable pressure of the
gas upon the water within it. The gas which is not
absorbed by the water in c or d, escapes by the aper-
ture at top. Another apparatus of great simplicity, T
and adapted to operating upon a more extended scale,
is delineated in the subjoined cut.
A is a strong plank on which the vessels are fixed; B is a bottle, con-
taining a quantity of pulverised carbonate of lime or chalk; C is the tubulure
and stopper of the bottle; D a bent tube for conveying the gas into the
bellows E, which are supported by the upright stand F, G is a stop-cock
connected with the tube D, which passes from thence into the strong
iron-hooped air-tight barrel H, suspended by its axis on the upright
22.2:
*=i-lim
ſº
º
















16 AERATED WATERS.
pillars II. In using this apparatus, the cask is to be half filled with distilled
or spring water; the hole K is then to be stopped air-tight with a good bung,
which is to be fastened down by means of the jointed straP, or hasp L, being
passed over the staple, and secured by a bolt or key Put through the same.
EA
/ º % sº. 2: == º
* & =| | || ".
- : i. = ŠE
B || # = #
lººk-Jº- Gºl,
| || A.
ºſſilſiläiſäliili （IIHill||||||||||||||||||||||||||}
Then pour through the tubulure of the bottle some sulphuric acid, diluted with
five or six times its weight of water, over the chalk, and close the aperture by
the screw-stopper C. Having taken off the weight from the bellows, the car-
bonic acid extricated from the chalk by the action of the acid, passes out of the
bottle into the bellows, through the tube D, which has an orifice opening under
them. When the bellows are fully distended, the cock G is to be turned, and
the weight being placed upon the bellows, the gas is thereby pressed downwards
into the barrel, and is there absorbed by the water, which is accelerated by
giving the barrel a few quick turns by the winch J. The contents of the barrel
may then be drawn off into stone bottles, which should be quickly corked, and
bound down with copper wire, to be preserved for use.
A very complete machine, invented by Mr. Cameron, of Glasgow, calculated
to offer a strong resistance to the pressure of the gas, and force a considerable
quantity into water, is shown on the next page. The gas generator a, is made of
cast iron, three quarters of an inch thick, and lined interiorly with sheet lead, (of
9 lbs. weight to the foot,) to prevent the action of the acid upon the iron. This
vessel contains about 15 gallons, and is filled up to the dotted line by a mixture
of whiting and water; it has an agitator b, also lined with sheet lead, and which
works on a pivot at the bottom, the axis passing through the stuffing-box c, at
the top of the vessel. The acid-holder e, is formed of lead, of the capacity of two
gallons, and is filled with oil of vitriol up to the dotted line. The acid is kept from
running down into the generator by means of the conical plug f which fits into
a conical opening in the leaden pipe g. This plug is attached to a rod, and
moves up and down through the stuffing-box h, and is prevented from turning
round by means of a pin k, moving in a slit in the bridle l, and the screw-nut
m, is rivetted loose into the top of the bridle. The pipe n, which forms a com-
munication between the top of the acid-holder e, and the pipes, in which the
plug-rod moves, preserves an equilibrium of pressure, so as to prevent the acid
from rising higher in the pipe s than the level of the acid in the acid holder,
by which means the brass work of the stuffing-box is preserved from injury.
To prevent any of the sulphuric acid from being carried over by the effervescence





AERATED WATERS. 17
an intermediate vessel o, containing about three gallons, is formed either of thick
sheet lead alone, or of cast iron, lined with lead. This intermediate vessel
is filled with water up to the dotted line. The impregnator w should contain
about 16 gallons. It may be made either of copper tinned, or of cast iron,
h
Ž
ſ
r
-|
lined with sheet-lead; and the agitator m may either be of tinned coppel, or
of maple-wood; which last, giving no taste to the water, is for that reason
preferable. This impregnator is filled up to the dotted line with water, to
which, in making saline waters, the proper proportion of sesqui-carbonate of
soda, carbonate of magnesia, or other ingredient, is to be added. A pressure-
guage t, of quicksilver, is to be placed at a little distance, and connected by
means of a leaden pipe. The operation of this apparatus is very simple. By
turning the nut m the plug is raised, allowing the sulphuric acid to run down
into the generator a, where it acts upon the whiting, disengaging the carbonic
acid gas in proportion to the quantity of sulphuric acid admitted at a time. The
nut ºn being turned the other way, lowers the plug, and stops the descent of the
sulphuric acid, thus regulating the disengagement of the gas, and preventing too
violent an effervescence. The disengaged gas passes through the intermediate
vessel into the impregnator v, where it is absorbed by the water. The impreg-
nated water is then drawn off into strong half-pint bottles, by means of a cock,
which descends to the bottom of the bottle; on withdrawing the bottle, it should
be instantly corked, and the corks be wired or tied down.
A patent has just been granted to Mr. F. C. Bakewell, of Hampstead, for a
very compact and ingenious apparatus for the preparation of aerated waters, the
peculiarity of which consists in the gas generating and the gas impregnating
apparatus being inclosed in the same vessel, and in the whole operation being
effected by a simple oscillating motion. A correct idea of this machine may be
formed by the annexed figure, (representing a vertical section of its principal
parts,) together with the subjoined explanation, a a exhibits an external casing of









18 AERATED WATERS
a cylindrical form, with spherical ends, made strong enough to resist a pressure
of several atmospheres; b is a partition, about two-thirds from the top of the
vessel, separating it into two parts. The bottom part c is a receptacle for the
chalk, or other suitable material, mixed into a pasty consistency with water; d is
-
r-
§
%+sy
..º
º W
- 2
SN
\\
a vessel containing dilute muriatic or Sulphuric acid, which is made to pas' out
in small quantities, as required, at the aperture e into the vessel c, fis a guard
to prevent the aperture e from being choked up; g is a pipe, of the form of
a truncated cone inverted, being about an inch diameter at bottom, and two
inches at the top. This pipe is fitted into an aperture in the partition b, and is
closed at the upper end; its object is for the ascent of the gas as it is generated,
which passes from the top down an external pipe, into the lower part i of a
vessel k, and through a small aperture the tenth of an inch diameter, (or through
several apertures whose total areas do not exceed the tenth of an inch,) through
the partition into the upper part of the vessel h. This vessel, which is deno-
minated the washing vessel, is furnished with two shelves, sloping in opposite
directions near its top, to detain the gas longer in its passage through the
aperture l to an external pipe, furnished with a perforated rose, for distri-
buting the gas as it escapes into the water to be impregnated, contained in the
vessels o o ; p is a stop-cock for drawing off the impregnated water as required;
q is an aperture for the introduction of the chalk and water; r, another for the
introduction of the acid; and s, another for the water to be aerated : each of
these apertures is provided with a screwed cap, to stop them securely after the
respective vessels have been charged. The apparatus is made to swing on two
pivots, one of which is shown in section at t. When the chalk and acid recep-
tacles are to be supplied with those ingredients, the apparatus is to be turned
on its pivots to a horizontal position, with the aperture r upwards, and a funnel
or hopper, with a bent stem, is to be employed in filling the vessel c c; n is an
end view of a pendulum or agitator, of the form of an arch of a circle, extending
across the bottom of the vessel, and suspended at its two extremities; one of the
suspension wires is shown in the drawing. The apparatus having been charged
as above described, is to be put into vibration on its pivots, by which the chalk
and water will be effectively agitated by the motion of the pendulum, while a









AETNA SALT. 19
small portion of acid will escape from the vessel d, into the vessel e, to keep up
the generation of the gas as it passes off to the water in a, which will, at the
same time, by the vibration of the apparatus, be thoroughly mixed with the gas
as it escapes through the rose n. An elegant apparatus, adapted for saturating
liquids with the carbonic acid, as well as other gases, was invented by M. Clement,
for which, see the article AbsorbiNG AND PRODUCTIVE CASCADE. Some manu-
facturers of aerated waters employ mechanical means to force the gas into the
water, by the use of a transferring pump or syringe, which is connected at one
end with a bladder, or other reservoir of the gas, and at the other, with a vessel,
or single bottle of water; the up-stroke of the pump extracting the gas from
the bladder, and the down-stroke transferring it into the water.
AERIAI, ACID. See CARBON1c Acid.
AERIFORM FLUIDS. A name frequently given to the gases.
AEROGRAPHY.) These three terms have been indifferently applied to
AEROLOGY. §: science which treats of the limits, dimensions, pres-
AEROMETRY. sure, elasticity, rarefaction, condensation, and other pro-
perties of our atmosphere; but these terms are generally disused by modern
writers on this branch of natural philosophy, by whom it is now designated
PNEUMATIcs, which see. See also AIR, ATMosPHERIC.
AEROMETER. An instrument, to which this name has been given by the
inventor, Dr. M. Hall, for making the necessary corrections in pneumatic ex-
periments to ascertain the mean bulk of the gases. It consists of a bulb of
glass, of 44 cubic inches capacity, blown at the end of a long tube, whose capa-
city is 1 cubic inch. This tube is inserted into another tube of nearly equal
length, which is supported on a sole; and the first tube is sustained at any
required height within the second, by the pressure of a spring. Five cubic inches
of atmospheric air, at a medium pressure and temperature, are to be introduced
into the bulb and tube, of the latter of which it will occupy one-half. The other
half of this tube, and part of the tube in which it is inserted, are to be occupied
by the fluid of the pneumatic trough, whether water or mercury. The point of
the tube at which the air and fluid meet, is to be marked by the figure 5, to
denote 5 cubic inches. The upper and lower halves of the tubes are each
divided into five parts, representing tenths of a cubic inch. The external tube
has a scale of inches attached.
AEROSTATION. The art of navigating the air in aerostatic machines.
See BALLoons.
AERUGO. The rust or oxide of metal, particularly that on copper, called
verdigris. Thus, in the Pharmacopeia Londinensis, prepared verdigris is termed
Aerugu praºparata.
AETHER. An extremely thin, subtle, penetrating fluid, much finer than
air, which has been considered by the ancient and many modern philosophers
to be diffused throughout the universe, but in its pure state to commence beyond
the limits of our atmosphere. The existence of such a fluid is wholly hypo-
thetical; yet it has given birth to conjectures as indefinite as the space which
has been assigned for its circulation. With some of the ancient philosophers it
was considered the origin of all things; an attenuation of fire; to be immortal;
knowing all things; seeing, hearing, and determining whatsoever is, or shall be
hereafter. From this fluid, existing only in perfection in the highest heavens,
all grosser elements were first derived, and, from these, the various productions
of nature. Here the gods were enthroned, and the stars rolled in sublime har-
mony around them Although the poets went hand in hand with the philo-
sophers in this speculation of science, it would long since have been exploded
from all connexion with the inductive philosophy, but for the sanction that has
been given to it by some conjectures of Sir Isaac Newton.
AETITES, or EAGLE-Stones; so called, from a popular notion that eagles
took them up into their nests to preserve their eggs from decay. They are
crustated hollow stones, containing a nucleus, which rattles on being shaken;
they usually consist of oxide of iron, mixed with silex and alumina.
AETNA SALT. The impure sal ammoniac found in the crevices of Ætna
and other volcanoes, and on the surfaces of the lava.
20 AGRICULTURAL IMPLEMENTS.
AE. (For many other words which were formerly commenced with this
diphthong, see the letter E.)
AFFINITY, CHEMICAL. See ATTRACTION.
AGARIC, MINERAL, or MountAIN MEAL, found in the clefts of rocks,
and on the roofs of caves, is a native carbonate of lime. It is used medicinally
in dysenteries and other disorders. N. Fabroni describes it as a stone of loose
consistence, abundant in Tuscany, of which bricks may be made either alone,
or with the admixture of one twentieth part of clay, so light as to float in
Water.
AGATE. A mineral whose basis is calcedony, blended with variable pro-
portions of jasper, amethyst, quartz, opal, heliotrope, and carnelian. Ribbon
agate consists of alternate and parallel layers of calcedony with jasper, or
quartz, or amethyst. The most beautiful comes from Liberia and Saxony;
it occurs in porphyry and gneiss. Brecciated agate is of Saxon origin; it
has a base of amethyst, containing fragments of ribbon agate, constituting the
beautiful variety. Fortification agate, found in Scotland and on the Rhine, is in
nodules of various shapes, imbedded in amygdaloid. On cutting it across, and
polishing it, the interior zig-zag parallel lines bear a considerable resemblance
to the plan of a modern fortification. In the very centre, quartz and amethyst
are seen in a splintery mass, surrounded by the jasper and calcedony. Mocha
stone, from Mocha, in Arabia, where it is chiefly found, is translucent calce-
dony, containing dark outlines of arborization, like vegetable filaments. Moss
agate, so called from its ramifications of a vegetable form, is a calcedony,
variously coloured, and occasionally traversed with irregular veins of red jasper.
An onyx agate set in a ring belonging to the earl of Powis, contains the chry-
salis of a moth. Agate is found in most countries, chiefly in trap rocks and
serpentine. The oriental agate is almost transparent, and of a vitreous appear-
ance. The occidental is of various colours, and often veined with quartz or
jasper. Agates are most prized when the internal figure nearly resembles some
animal or plant. Agates are artificially coloured by immersion in metallic
solutions. They are extensively used in Paris for making cups, rings, seals,
handles for knives and forks, sword hilts, beads, smelling bottles, snuff boxes,
&c. At Oberstein, on the Rhine, where the stones are abundant, they are cut
and polished on a considerable scale, and at a very moderate price. The surface
to be polished is first coarsely ground by large millstones of a hard reddish
sand-stone, moved by water. The polish is afterwards given on a wheel of soft
wood, moistened and imbued with a fine powder of hard red tripoli, found in
the neighbourhood. Antiquaries use the term agate to denote a stone of the
kind engraved by art. . In this sense agates make a species of antique gems, in
the workmanship of which we find eminent proofs of the great skill and dex-
terity of the sculptor. Several agates of exquisite beauty are preserved in the
cabinets of the curious.
AGENT, in a general sense, denotes any active power or cause. In natural
philosophy, the term is applied to such bodies as have a power to act upon other
bodies in a certain and determinate manner.
AGGREGATE, in a general sense, is the sum of several things added
together. In chemistry, the united mass is called an aggregate, when it does
not differ in its chemical properties from the bodies of which it was originally
composed. Elementary writers call the smallest parts into which an aggregate
can be divided, without destroying its chemical properties, integrant parts. Thus
we may conceive the integrant parts of common salt to be the smallest parts
which can remain without change; and beyond these, that any further sub-
division cannot be made without developing the component parts, the alkali and
the acid; and that the division of the latter must resolve them into their con-
stituent principles.
AGITATION. In general, the act of shaking a body, or tossing it about.
AGITATORS. Instruments used in various processes for the purpose of
agitation. See BREwing, Distillation, Evapor ATIon, &c.
AGRICULTURAL IMPLEMENTS. See, under the respective heads.
Plough, HARRow, &c.
AGRICULTURE. 21
AGRICULTURE is the art of cultivating the earth, so as to preserve or
increase the maiurai fertility of the soil, as well as to render steriie tracts pro-
ductive of vegetation useful to man; and the perfection of this art may be said
to consist in obtaining the greatest quantity of the required product, from a
given quantity of land, at the least possible expense of labour and material.
Besides the production of grain and leguminous plants, which usually forms the
chief business of the farmer, agriculture includes the culture of trees, and
every description of plants; their planting, pruning, grafting, &c.; hence
horticulture, or gardening, is a branch of this art. It includes also the breeding
and management of cattle, since their manure and their labour are essential to
the business of husbandry. Nothing would tend more to the successful practice
of this the most important of all arts, than the study of chemistry by the farmers.
If a soil be unproductive, it must be owing to some defect in its constitution,
which may not be apparent even to the eye of the most experienced hus-
bandman. Not all his observation, nor all his practice, without the aid of
chemical knowledge, will afford him any means either of ascertaining the cause,
or removing the effect. By chemical analysis, however, the cause is readily
determined, and the remedy made obvious. If the salts of iron be present, they
may be decomposed by lime; if an excess of silicious sand, the application of
clay and calcareous matter will improve it; if vegetable matter be in excess,
liming, or paring and burning, will be advantageous. The excellent rules laid
down by Sir Humphrey Davy, in his Agricultural Chemistry, are particularly
deserving of attention. In cases where a barren soil is examined with a view
to its improvement, it ought, in all cases, if possible, to be compared with an
extremely fertile soil in the neighbourhood, and in a similar situation. The
difference given by their analyses would indicate the methods of cultivation, and
thus the plan of improvement would be founded upon accurate scientific prin-
ciples. If the fertile soil contained a large quantity of sand in proportion to the
barren soil, the process of melioration would depend simply upon a supply of
this substance; and the method would be equally simple with regard to soils
deficient in clay or calcareous matter. In the application of clay, sand, loam, marl,
or chalk, to lands, there are no particular cherºical principles to be observed; but
when quick-lime is used, great care must be taken that it is not obtained from
the magnesian limestone, for in this case, as has been shewn by Mr. Tennant,
it is exceedingly injurious to land. The magnesian limestone may be distin-
guished from the common limestone by its greater hardness, and by the length
of time that it requires for its solution in acids; and it may be analysed by the
process for carbonate of lime and magnesia. When the analytical comparison
indicates an excess of vegetable matter as the cause of sterility, it may be
destroyed by much pulverization and exposure to air, by paring and burning,
or the agency of recently made quick lime. The deficiency of either animal or
vegetable matter, must, of course, be supplied by animal or vegetable manure.
The general indications of fertility and barrenness, as found by chemical expe-
riments, must necessarily differ in different climates, and under different cir-
cumstances. The power of soils to absorb moisture, a principle essential to
their productiveness, ought to be much greater in warm and dry countries than
in cold and moist ones; and the quantity of fine aluminous earth they contain
should be larger. Soils, likewise, that are situated on declivities, ought to be
more absorbent than those in the same climate on plains or in valleys. The pro-
ductiveness of soils must likewise be influenced by the nature of the subsoils,
or the earthy or stony strata on which they rest; and this circumstance ought
to be particularly attended to in considering their chemical nature, and the
system of improvement. Thus, a sandy soil may owe its fertility to the power
of the subsoil to retain water; and an absorbent clayey soil may occasionally
be prevented from being barren in a moist climate, by the influence of a sub-
stratum of sand or gravel. Those soils that are most productive of corn, contain
always certain proportions of aluminous or caleareous earth in a finely-divided
state, and a certain quantity of vegetable or animal matter. The quantity of
calcareous earth is, however, very various, and, in some cases, exceedingly small.
A very fertile corn soil from Ormesten, in East Lothian, afforded in 100 parts
I)
22 AILERON.
only 11 parts of fine calcareous earth; the finely-divided clay amounting to 45
varts. It lost 9 parts in decomposed animal and vegetable matter, and 4,in
water, and exhibited indications of a small quantity of phosphate of lime. This
soil was of a very fine texture, and contained very few stones and vegetable
fibres. It is not unlikely that its fertility was in some measure connected with
the phosphate, for this substance is found in wheat, oats, and barley, and may
be a part of their food. A soil from the lowlands of Somersetshire, celebrated
for producing excellent crops of wheat and beans without manure, Sir Humphrey
Davy found to consist of one-ninth of sand, chiefly silicious, and eight-ninths
of calcareous marl, tinged with iron, and containing about five parts in the
hundred of vegetable matter. He could not detect in it any phosphate or
sulphate of lime, so that its fertility must have depended principally upon its
power of attracting principles of vegetable nourishment from water and the
atmosphere. In some experiments made by Mr. Tillet on the composition of
soils about Paris, he found that a soil composed of three-eighths of clay, two-
eighths of river sand, and three-eighths of the parings of limestone, was very
proper for wheat. In general, bulbous roots require a soil much more sandy
and absorbent than the grasses. A very good potatoe soil, from Warsel, in
Cornwall, afforded seven-eighths of silicious sand, and its absorbent power was
so small, that 100 parts lost only 2 by drying at 400° Fahrenheit. Plants and
trees, the roots of which are fibrous and hard, and capable of penetrating deeply
into the earth, will vegetate to advantage in almost all common soils that are
moderately dry, and do not contain a very great excess of vegetable matter.
The soil taken from a field at Sheffield-place, in Sussex, remarkable for pro-
ducing flourishing oats, was found to consist of 6 parts of sand, and 1 part of
clay and finely divided matter; and 100 parts of the entire soil submitted to
analysis, produced water, 3; silex, 54; alumina, 28; carbonate of lime, 3;
oxide of iron, 5; decomposing vegetable matter, 4; loss, 3. From the great
difference of the causes that influence the productiveness of lands, it is obvious,
that in the present state of science, no certain system can be devised for their
improvement, independent of experiment; but there are few cases in which the
labour of analytical trials will not be amply repaid by the certainty with which
they denote the best methods of melioration; and this will particularly happen,
when the defect of composition is found in the proportions of the primitive
earths. . In supplying animal or vegetable manure, a temporary food only is
provided for plants, which is in all cases exhausted by means of a certain
number of crops; but when a soil is rendered of the best possible constitution
and texture, with regard to its earthy parts, its fertility may be considered as
permanently established. It becomes capable of attracting a very large portion
of vegetable nourishment from the atmosphere, and of producing its crops with
comparatively little labour and expense. For the mode of proceeding, and the
instruments required in making analytical experiments on soils, we can refer
the reader to the before-mentioned work of the late illustrious chemist; very
accurate information on this subject will, however, be found in Dr. Ure's ex-
cellent Dictionary of Chemistry. But to those whose business it may be to
pursue this most important of studies, in all its interesting details, we strongly
recommend the perusal of the articles Agriculture, in the Oxford Encyclopædia
and Supplement, which form together an elaborate compendium of the best
works on the subject in the English language, enriched throughout by the judi-
cious observations of its learned editors.
AIGREMORE. A name given to charcoal, when in that state of preparation
for the making of gunpowder, which renders it fit for the admixture of the other
constituent materials.
AIGUILLE, (From the French, needle.) The name of an instrument used
by military engineers, for piercing a rock for the lodgment of gunpowder in a
mine. A similar instrument is used in the common operations of mining and
the blasting of rocks.
AILERON. An abutment or starling erected in a river or strong current,
to prevent the action of the water from destroying the supports of a bridge, or
other building similarly circumstanced.
AIR-PUMP. 23
AIR, Atwospheric. From the remotest antiquity, until a comparatively
recent period, the air was considered as one of four elements, of which all
things were compounded; and it was generally held to be an invisible, impon-
derable, and simple substance. Some of the ancients, it is true, had vague
notions of its gravitating power and of its elasticity; amongst others may be
mentioned Aristotle, who says, that a bladder filled with air weighs more than
when quite empty; and Hero also says, that the air, in a given cavity, may be
rarefied by sucking out a part of it; but still their ideas were very imperfect,
and their opinions were abandoned by their followers, for various absurd hypo-
theses by which they attempted to account for the phenomena produced by the
action of the atmosphere. It was not until near the middle of the seventeenth
century, that the real nature and properties of the atmosphere were ascertained
with precision and confirmed by experiment. For these discoveries we are
principally indebted to Galileo, and his pupil Torricelli. Galileo taught that
the air had weight, but does not appear to have applied this idea to explain
those pneumatic phenomena which were then absurdly attributed to an imagi-
nary principle of nature, termed a horror of a void: but Torricelli following up
the principle, shewed, by incontrovertible experiment, that the rise of fluids in,
pumps was owing to the pressure of the atmosphere, and that the height to
which fluids would rise in vacuo, was exactly proportionate to their weight,
which would, in all cases, be exactly equal to a column of air of the same base,
and of the height of the atmosphere. These great principles were successfully
followed up by various eminent philosophers, and numerous important con-
clusions and useful applications of them were the result. Towards the close of
the nineteenth century, the air was discovered to be a compound of two gases,
to which the names of oxygen and azote were given, and this discovery served
as the basis of the modern system of chemistry, which has been so fertile in
brilliant scientific results. Under the articles CHEMISTRY and PNEUMAT1cs
will be found the demonstrations of the chemical and physical properties of the
atmosphere; we shall, therefore, in this place, merely state what are its prin-
cipal characteristics, and the uses to which they are made subservient in many
processes of the arts and manufactures. Air, then, is an invisible elastic and
ponderable gaseous fluid, its bulk and density depending upon its temperature,
and the pressure to which it is exposed. Under a pressure of 30 inches of
mercury, and at a temperature of 600 Fahrenheit, its spec. grav. as ascertained
with great care and accuracy by Messrs. Arago and Biot, is .00122, water being
1.00000, or it is 820 times lighter than water; and if we take a cubic inch of
water to weigh 252.525 grains, then 100 cubic inches of air will weigh 30.808
grains, and a cubic foot will weigh 532.36 grains. Mariotte ascertained that
its bulk is inversely as the pressure, a double pressure reducing a given volume
to half its bulk. The applicability of this law to air under very great pressure,
has been questioned, but not satisfactorily disproved; and for all practical pur-
i. it may be safely received; whilst, frºm its simplicity, it may be remem-
ered with ease and applied with facility. Air expands by an increase of
temperature, the rate of expansion is not exactly equal for equal increments
of heat, but on an average, the increase of bulk above 320 Fahrenheit is # of
its bulk, for each degree of heat on the same scale. The expansion or rare-
faction of air is accompanied by a decrease of its temperature, and in its conden-
sation or compression, it gives out a proportional quantity of heat. Air can take
up and hold in solution a portion of water depending upon the temperature.
AIR-PUMP. An instrument or machine for exhausting or rarefying the
air in closed vessels, and very generally employed to illustrate the properties of
air, and to explain the various phenomena connected with the science of
pneumatics. #. inventor of the air-pump was Otto Guericke, a magistrate
of Magdeburgh; his machine was of a rude and inconvenient structure, and
worked under water, but a description of it having been received by Mr.
Boyle, he, with the assistance of Dr. Hook, introduced such improvements in
the construction as to render the machine extremely serviceable in philosophical
experiments upon the nature and properties of the atmosphere. Numerous
improvements have since been made by Hawksbee, Grazesand, Smeaton
24 AIR-PUMP.
Prince, and others; but more especially by Mr. Cuthbertson, whose arrange-
ments are so excellent as to claim a particular notice and description.
Fig. 1.
|
Fig. 1 represents a perspective view of the machine, with its two principal
gauges screwed into their places, which need not, however, be used together
except in cases requiring the utmost exactness; but in common experiments,
one of them is removed, and a stop-cock put in its place. Fig. 2 is a section
of one of the barrels, with all its internal parts; Fig. 3 a section of the piston ;
and Figs. 4 and 5 parts of the piston, shewn detached for the sake of perspicuity.
In Fig. 2, CD represents the barrel, F the collar of leathers, G a hollow cylin-
drical vessel to contain oil; R is also an oil-vessel to receive the oil which is drawn
along with the air from the barrel when the piston is drawn upwards, and
when this vessel is full the oil is carried over with the air along the tube T
into the oil vessel G; c. c is a wire which is driven upwards from the hole, by
the passage of the air, and as soon as this has escaped, it falls down again by


AIR-PUMP. 25
its own weight, shuts the hole, and prevents the return of the air into the
barrel; at d are fixed two pieces of brass to keep the wire c c in a vertical
position, in order that it may accurately shut the hole. H is the piston rod,
having a rack on the upper end, and made hollow to receive a long wire 9,
which opens and shuts the hole L; on the lower end of this wire is screwed a
nut o, which, by stopping in the narrowest part of the hole, prevents the wire
g from being drawn up too far. This nut and screw are seen more distinctly
in Fig. 3; the wire slides in a collar of leathers shewn in Figs. 3 and 5 in the
middle piece of the piston. Figs. 4 and 5 are the two main pieces which com-
pose the piston, which is shewn entire in Fig. 3; Fig. 5 is a conical piece of
brass having a shoulder at bottom ; a long hollow screw is cut about two-thirds
of its length, and the remaining part of the hole, in which there is no screw, is
about the same diameter as the screwed part, except a thin plate at the end,
where the diameter of the hole is just equal to that of the wire g.g. That part
of the inside of the conical brass in which no screw is cut, is filled with oiled
Fig. 3.
Fig. 4.
leathers, having holes in them, through which the wire can slide stiffly; a short
external screw, working in the internal screw, and a washer with holes in them,
through which the wire g passes, serve to compress the leathers. a a Figs. 3
and 4 is the outside of the piston, the inside of which is turned so as exactly to

26 AIR-PUMP.
fit the outside of Fig. 5; b b, Fig. 3, are round leathers, about 60 in number
of the same diameter as the barrel C D, and having holes in the centre to
receive a a ; a circular plate, or washer, c c, Fig. 3, is placed over the leather,
and a nut d d, upon a screw cut upon the upper end of a a, serves to compress
them. The piston rod H is screwed into the middle piece of the piston, Fig. 5,
and when drawn upwards, it will cause Fig. 5 to shut close into Fig. 4, and
drive out the air above it; but when pushed down it will open as far as the
shoulder on the rod will allow, and permit the air to pass between Figs. 5 and
4. Having thus described at large the several parts of this machine, we proceed
to explain the process of rarefaction, which is carried on in the following man-
ner:—Conceive the piston to be at the bottom of the barrel, the inside of which
contains common air. Now when the rod is drawn up, the upper part of the
piston sticks fast in the barrel, till the conical part connected with the rod shuts
the conical hole, and its shoulder applies close to its bottom. The piston being
now shut, the whole is drawn up by the rack-work driving the air before it
through the aperture, into the oil vessel at r, and out into the atmosphere by the
tube T. The piston will then be at the top of the barrel, and the wire g
will stand º as shewn in the figure, just raised from the hole L, where it
is prevented from rising higher by the nut O. During this motion, the air will
expand in the receiver, and come along the bent tube into the barrel; by
this means the barrel will be again filled with air, which, as the piston rises,
will be rarefied in the proportion of the capacity of the receiver, pipes, and
barrel together, to that of the latter alone. When the piston is moved down
again by the rack-work, it will force the conical part, Fig. 5, out of the hollow
part, Fig. 4, as far as the shoulders a a. Fig. 3 will rest on a a, Fig 4, which
will then be so far open as to permit the air to pass freely through it, while at
the same time the end of g g is forced against the top of the hole, and, by
shutting, prevents any air from returning into the receiver; thus the piston
moving downwards suffers the air to pass out between the sides of Figs. 4 and 5,
and when it is at the bottom of the barrel, it will have the column of air above
it, and, consequently, when drawn up, it will shut and drive out the air, and by
opening the hole at L, will at the same time give a free passage to more air
from the receiver. This process being continued, the air of the receiver will
be rarefied as far as its expansive powers will permit, for in this machine there
are no valves to be forced open by the elasticity of the air in the receiver,
which at last it is unable to effect; there is, therefore, nothing to prevent the
air from expanding to its utmost degree, which is the peculiar excellency of
this construction.
Although the machine just described is equally adapted for condensing air
as for rarefying it, by merely connecting the bent pipe with the oil vessel R,
instead of the lower part of the pump, yet as the former operation seldom
requires the same delicacy of process, it is frequently effected by a simpler
machine, termed a condensing syringe. The following description will give an
idea of the ordinary construction of this instrument. a is a cylindrical tube of
small diameter, open at one end, the other end perforated with a very small hole
b, and being turned externally to a very small cylinder. A strip of bladder, or of
thin leather, soaked in a mixture of oil and tallow, must be tied over the hole.
On the end of the cylinder is cut an external screw, to attach it to the vessel
in which the air is to be condensed. c is the piston moving air-tight in a d,
the piston rod screwing into c.; this rod is perforated with a small hole throughout

AIR-PUMP. 27
its length, the lower end of the hole having a valve e, similar to the valve * in
the cylinder, and opening into the cylinder. To the upper end of the rod is
fixed a handle. g is the neck of the receiver, having a hollow screw fitting the
solid screw on the end of the cylinder. Now when the piston is drawn up, a
void is left below it, and the external air rushing through the perforation of the
piston rod, opens the valve e, and fills the cylinder. Then, on pushing down
the piston, the valve e closes; the air being compressed into less space, presses
on the valve g, shuts it, and none escaping through the piston, it is graduall
condensed as the piston descends till it opens the valve b, and is added to the
air already accumulated in g. We may thus force into the vessel any quantity
of air consistent with its strength; and if the receiver be furnished with a stop-
eock, the cock may be turned, and the receiver be detached from the syringe,
and thus be in a state to be transferred to any other purpose required. In all
cases where considerable force is required, and, consequently, a great conden-
sation of air, it will be requisite to have the condensing syringe of small bore,
perhaps not exceeding half an inch diameter, otherwise the force requisite to
produce the compression will become so great, that the operator will not be able
to work the machine; for as the pressure against each square inch is about
15 lbs. for each additional volume of air forced into the receiver, and 12 lbs. upon
each circular inch, if the syringe be of 1 inch diameter, it will require a force
of 120lbs. to condense ten volumes of air into the barrel, whereas with a half-
inch bore it would only require 30 lbs.
We insert the following description of an air-pump on account of its extreme
simplicity. It is the invention of Mr. W. Ritchie, and has no artificial valves,
which, as commonly constructed, are very liable to be deranged, and the repairs
are attended with considerable trouble and expense. The machine consists of
a barrel shut at the lower end, and having a small
aperture at c, forming a free communication with the CZ
receiver at f: the piston d is solid, and stuffed in the e
usual way. The piston rodworksin a small stuffing-box at
a, so as to render it completely air tight. There is a small
aperture at e, in the top of the barrel, to allow the air to
make its escape when the piston is raised. The air-pump
may be worked in the usual way, or by the method of
continued motion. In commencing the exhaustion of the
receiver, the piston is supposed to be below the small
aperture at c. The piston is then raised, and the air
which occupied the barrel is forced out through the f
aperture at e. The point of one of the fingers is applied
to the perforation in the same manner as in playing
the German flute. The air easily passes by the finger Ž
which, when the piston begins to descend, shuts the
opening, and completely prevents the entrance of the
external air. The piston is again forced down below
the opening c, the air in the receiver rushes into the
barrel, and is again expelled by the ascending piston. Since the air in the
receiver has no valve to open by its elasticity, it is obvious that there is no limit
to the degree of exhaustion, as in the common construction. For a long time
the use of the air-pump was confined to the purposes of philosophical experi-
ment: the first application of it to mechanical purposes was made by Bolton
and Watt, in their steam engines, where it is used for drawing off the air
extricated from water by boiling, as also the water used for condensing the
steam; and about twenty years ago, the Hon. E. Howard availing .# of a
well-known principle, that liquids enter inzo ebullition at a much lower degree
of temperature in vacuo, than when under the pressure of the atmosphere,
introduced a most important improvement in the process of sugar refining, by
concentrating the syrup in close vessels, in which a vacuum is maintained by
means of an air-pump; and subsequently, Messrs. Allen & Co. of Plough Court,
have adopted the principle in preparing the more delicate medicinal extracts.
A patent has also been taken out for more speedily tanning leather, by enclosing

28 AIR-PUMP.
the skins in boxes, and exhausting the air from the upper surface of the skins,
whilst the lower surface is exposed to the tanning liquor, which is forced into
the pores by the pressure of the atmosphere. Dr. Church, of Birmingham, also
has a patent for improvements in casting metals, which consists in exhausting
the air from the moulds; and patents have been taken out for distillation in
vacuo, all of which applications of the air-pump we propose to explain in detail
when we come to treat of the above-named manufacturing processes.
In the description of Cuthbertson's air-pump it was stated that it was equally
applicable to the condensation of air, as to its exhaustion. We now present to
our readers a condensing air-pump of a different description, which is the
invention of the late Mr. D. Gordon, of the Portable Gas Works, where it was
used for compressing the gas into the portable gas-holders, and will be found
§
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QM ºf . * * N |
fºº/ā āº $E|| || ||
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a- NS || || ||
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very effective in subjecting any air or gas to a great compression, as the whole
volume of gas taken into the pump at each stroke is effectually discharged, the
mercury º in the pump completely excluding every portion from below
the delivery valve. The figure represents a vertical section of one of the pumps

















AIR-G UN. 29
with the plunger a at its lowest immersion, or down-stroke, as it is called.
At this moment of time every part of the syphon is completely filled with the
fluid it contains to the entire exclusion of atmospheric air, the deeply shadowed
part c being water, and the lighter tint, quicksilver. It will therefore be easily
conceived that when the plunger is withdrawn by the up-stroke, an empty
space or vacuum, equal to the cubic admeasurement of the plunger, will be left
in the syphon; and as mercury is a much heavier body than water, the latter
is pushed up by the former, and follows the plunger as it ascends. The mercury,
consequently, sinks below its present level, which causes the “suction valve’ e
to open, and to let in a volume of gas at the ordinary pressure, which flows
from a gasometer, or gas-holder, through the pipe f. At the down-stroke of
the plunger, the gas is then compressed and forced through the discharge valve,
(which opens only outward) into the pipe h, which leads to a strong recipient
into which the gas is condensed. The action of the pumps being continued,
the compression of the gas is effected to whatever degree may be required,
provided the power of the gas engine, or other first mover, be adequate. In
the Portable Gas Works above-mentioned, there were recently nine pumps in
operation, worked by a 10-horse engine. The quicksilver and water are poured
into the syphon by means of the basin and perforation at i, the aperture at k
being opened to allow the air to escape; the aperture k is next made perfectly
tight by a plug, which is screwed into the orifice, during which time the water is
continually being poured in at i, to expel the air completely, and fill up every
crevice with the fluid; another plug is then screwed into the orifice at i, with
the water above it. After this, the first down-stroke of the plunger expels the
atmospheric air on the surface of the mercury, in the short leg of the syphon,
and the pump is then ready to perform the office of alternately drawing in the
gas from the gas-holder, and compressing it into the portable lamps. The gas
sent out by the company is compressed into ; of its original volume.
AIR-GUN. A machine in which highly-compressed air is substituted for
gunpowder to expel the ball, which will be projected forward with greater or
less velocity, according to the state of condensation, and the weight of the body
projected. The effect will, therefore, be similar to that of a gun charged with
gunpowder, for inflamed gunpowder is nothing more than air very greatly con-
densed, so that the two forces are exactly similar. The elasticity of the air
generated by the inflammation of gunpowder has been estimated by Mr. Robins
as equal to about 1000 times that of common air; it would therefore be requisite
to condense air into one-thousandth part of its original bulk to produce the effects
of gunpowder. There is, however, this important consideration to be attended
to, viz. that the velocities with which balls are impelled are directly proportional
to the square root of the forces; so that if the air in an air-gun be condensed
only ten times, the velocity will be equal to ; of that arising from gunpowder;
if condensed twenty times, the velocity would be that of gunpowder, and so
on. Air-guns, however, project their balls with a much greater velocity than that
assigned above, and for this reason, that, as the reservoir or magazine of con-
densed air is commonly very large in proportion to the tube which contains the
ball, its density is very little altered by passing through that narrow tube, and
consequently the ball is urged all the way by nearly the same force as at the
first instant; whereas the elastic fluid arising from inflamed gunpowder is but
very small indeed in proportion to the tube or barrel of the gun, and therefore
by dilating into a comparatively large space as it urges the ball along the barrel,
its force is proportionally weakened, and it always acts less and less on the ball in
the tube. Hence it happens, that air condensed only ten times into a pretty large
receiver, will project its ball with a velocity little inferior to that of gunpowder.
Having thus explained the principle of the machine, we shall proceed to describe
the construction of one : that by Martin is perhaps the best, and is as follows:—
It consists of a lock, stock, barrel, ramrod, &c. of about the size and weight of
a common fowling-piece. Under the lock at b is screwed on a hollow copper
ball c, perfectly air-tight. This ball is fully charged with condensed air, by
means of the syringe B, previous to its being applied to the tube at b. Being
charged and screwed on as above stated, if a bullet be rammed down in the
} .
3ſ) AIR-GUN.
barrel, and the trigger a be pulled, the pin in b will, by the spring-work in the
lock, forcibly strike out into the ball, and thence by pushing it suddenly, a valve
within it will let out a portion of the condensed air, which, rushing through
the aperture in the lock, will act forcibly against the ball, impelling it to the
distance of 60 or 70 yards, or further, if the air be strongly compressed. At
every discharge only a portion of the air escapes from the ball; therefore, by
re-cocking the piece another discharge may be made, which may be repeated
for a number of times proportioned to the size of the ball. The air in the
copper ball is condensed by the syringe B in the following manner. The ball
is screwed quite close on the top of the syringe; at the end of the steel-pointed
rod a is a stout ring, through which passes the rod k ; upon this rod the feet
should be firmly set; then the hands are to be applied to the two handles i i
fixed on the side of the barrel of the syringe, when, by moving the barrel B
steadily up and down on the rod a, the ball c will become charged with con-
densed air, and the progress of condensation may be estimated by the increasing
difficulty in forcing down the syringe. At the end of the rod k is usually a
square hole, that the rod may serve as a key for attaching the ball to either the
gun or syringe. In the inside of the ball is fixed a valve and spring, which
gives way to the admission of the air, but upon its emission, comes close up to
the orifice, shutting out the external air. The piston rod works air-tight by a
collar of leather on it, in the barrel B; it is therefore obvious that when the
barrel is drawn up, the air will rush in at the hole h; when it is pushed down,
it will have no other way to pass from the pressure of the piston but into the
ball c at the top. The barrel being drawn up, the operation is repeated, until
the condensation is so great as to resist the action of the piston. If air be very
suddenly compressed into a small compass, the heat given out is so considerable,
as to be sufficient to ignite inflammable substances. This discovery was made,
accidentally, by a French soldier, who, in cleaning his musket with some wadding
fastened to the ramrod, found, after thrusting the ramrod suddenly down the
piece, that the wadding had ignited. The fact he communicated to the National
Institute, and repeated the experiment in their presence. This property has
been turned to advantage in an apparatus denominated, “An Instantaneous
Light Machine,” constructed in a walking stick, which consists of a piston
accurately fitted and worked in a cylinder, by the sudden stroke of which the
volume of air contained in the cylinder becomes so much compressed as to give
out sufficient heat to set fire to a piece of the substance termed German tinder.
A patent was also taken out in 1826, by Mr. Newmarch, of Cheltenham, for a
similar method of exploding fire-arms, by means of a cylinder and piston,
enclosed in the stock behind the breech, which has a small hole, closed by a

AIR-PRESSURE ENGINES. 31
valve. The piston is forced back, by means of a lever, against a powerful
spring, and upon being released, is impelled forward into the cylinder with such
force, as to cause the air before it to give out its caloric in the state of sensible
heat or fire at the aperture in the breech, which passing the valve, enters the
barrel, and instantly ignites the charge of powder.
AIR-PRESSURE ENGINES. Engines in which the difference of pres-
sure of air of different densities is employed as a motive force. From the
extreme lightness and mobility of air, it has been frequently proposed to employ
it as a medium for transmitting motion to machinery at a considerable distance
from the prime mover. Amongst the first who attempted this, is the cele-
brated Papin, who invented the steelyard safety-valve. He employed a fall
of water to compress the air in a cylinder, through the medium of an interven-
ing piston; and he connected this cylinder to another, at the mouth of a mine
a mile distant, by means of a pipe of that length. In the second cylinder was
another piston, the rod of which was intended to work a set of pumps; but
contrary to expectation, the compression of the air in the first cylinder produced
no movement in the piston of the second. Papin subsequently attempted to
bring his scheme into use in England, but did not succeed. A. how-
ever, he erected great machines in Auvergne and Westphalia, for draining
mines, but so far from being effective machines, they would not even begin to
move. He attributed the failure to the quantity of air in the pipe, which must
be condensed before it can condense the air in the remote cylinder; he there-
fore diminished the size of this pipe, and made his water machine exhaust
instead of condense, and had no doubt that the immense velocity with which
air rushes into a void, would make a rapid and effectual communication of
power. But the machine stood still as before. Near a century after this, an
engineer at an iron foundry in Wales, erected a machine at a powerful fall of
water, which worked a set of cylinder bellows, the blow-pipe of which was con-
ducted to the distance of a mile and a half, where it was applied to a blast
furnace; but notwithstanding every care to make the conducting pipe very air-
tight, of great size, and as smooth as possible, it would hardly blow out a candle.
The failure was ascribed to the impossibility of making the pipe air-tight; but
above ten minutes elapsed after the action of the piston in the bellows, before
the least wind could be perceived at the end of the pipe, whereas the engineer
had calculated that the interval would not exceed six seconds. The foregoing
particulars are taken from Dr. Robinson's Natural Philosophy, art. Pneumatics,
and an explanation is offered of this curious phenomenon; but on account
of its prolixity, we omit it; but the following remarks, which appeared in
the Franklin Journal, are deserving of notice. “If we take a particular care,
and calculate the resistance of air moving through pipes according to ac-
knowledged principles, we shall find nothing mysterious in the above result.
It will be found, that if the blow-pipe is 3 inches in diameter, and only a
mile long, the air at one end must be kept constantly condensed by a pres-
sure equal to 5; atmospheres to produce a velocity of 128 feet per second ;
and yet this velocity gives only 2304 gallons per minute, only about half the
quantity used in the furnaces of Europe; a blast furnace there expels 720
cubic feet of air per minute, (Mech. Philos. Vol. VIII. p. 784,) if we calculate
the velocity of water issuing from a pipe a mile long, and 3 inches in diameter,
under a 9-foot head and fall, to be 1 foot per second. Now, as equal velocities
are known to be generated in all fluids by equal heads, all other circumstances
being equal, it will follow that a 9-foot head of air, or is of a head of 9 feet of
water, will generate in air a velocity of 1 foot per second in a tube 3 inches in
diameter, and a mile long. Again, it is known both from theory and experiment,
that the heads of pressure generating velocities in fluids, are as the squares of
the velocities; now the square of 1 is 1, and the square of 128 is 16,384, there
fore the head of pressure due to the velocity of 128 feet, is obtained by the
following proportion, as 1 : 16384:: 9 : 147456, and this number divided by
800, gives 1844 equal to a pressure of 5; atmospheres, as before said: now if
we suppose this velocity doubled, or 256 feet a second, in order to discharge air
enough for a blast furnace, the head of pressure must be four times as great, or
32 AIR-PRESSURE ENGINES.
upwards of 21 atmospheres. This would require a machine of 3426 horse
power, provided a horse can work eight hours a day, raising 140 lbs. 200 feet
per minute. Notwithstanding the failure of both of the plans of Papin, and
the plausible arguments against them just quoted, they have been recently
revived in this country. Mr. Samuel Wright has taken out a patent for trans.
mitting power to machinery by means of condensed air; but we have not heard
of any erections on the principle. Mr. Hague, however, has taken out
patents for effecting the same object by the rarefaction of air by an air-pump,
and has established several machines upon this principle, the successful operation
of which leaves no doubt that the failure of Papin must have arisen from some
defective arrangements, or imperfect workmanship. We have selected a few of
those machines to which Mr. Hague considers the principle as peculiarly
applicable. The first of these which we shall describe, is a crane for raising
gºods into lofty warehouses; but previous to showing the actual arrangement
of the machinery, we shall explain the principle by means of the accompanying
figure.
Air-Pressure Bngine, A.
| ...
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AIR-PRESSURE ENGINES. 33
a represents the side of a warehouse; b a cylinder truly bored, and fixed ver-
tically to the wall; e a pisten fitting air-tight in the game cylinder, and st:3.
pended from a rope or chain passing over the jib k; g a load attached to
the rope; d a double-barrelled air-pump worked by the two cranks which may
be turned by hand or by steam ; e a pipe of communication between the air-
pumps and the cylinder, and fitted with a cock f. Now if the pumps be set in
motion, the air in the cylinder will become more and more rarefied, and the
pressure of the external air will at length so far exceed the internal pressure, as
to cause the piston to descend, and, consequently, to raise the load g. But this
would be an exceedingly inconvenient form ; for the machine, in its powers,
would be confined within very narrow limits by the largest cylinders which
could be constructed; but in the excellent arrangements of Mr. Hague, which
we now proceed to describe, it will be seen that any load, however great, may
be raised to any required height. In the subjoined engraving a represents a

34 A [R-PRESSURE ENGINES.
working cylinder vibrating upon gudgeons, one of which has passages leading
to the top and bottom of the cylinder; b piston rod connected to the crank ;
a d guide rods; e pinion on axis of the crank, driving f a toothed wheel on the
axis of the drum g; i the valve-box, in which the hollow gudgeon of the cylin-
der turns, and, admitting the atmosphere to press upon one side of the piston
whilst the air is drawn from the opposite side by an air-pump worked by a steam-
engine; k the spanner for reversing and regulating the motions of the machine;
e pipe leading to the air-pump; m fly-wheel.
§
N
§ N
The above figure represents a swing-round crane, upon the same principles as
the former, and may be supposed to form one of a range round a dock basin.
a is a hollow cast-iron post, upon which the crane turns, and is firmly imbedded
in masonry; from the upper end proceeds a pipe b turning air-tight in a
stuffing-box, and communicating with a cylinder d by means of a three-way
cock c. The cylinder vibrates upon gudgeons, in one of which are formed two
hollow passages, the one leading to the top, and the other to the bottom, of the
cylinder. A pipe e proceeds from an aperture f in the crane post to an air-
pump, worked by a steam-engine, or any other power, and which may be
situated in any part of the docks, the air being rarified alternately above and
below the piston of the vibrating cylinder, whilst the atmosphere presses upon
the opposite side of the piston; the alternate motion of the latter turns the
crank g and the piston h, which drives the wheel k fixed upon the axis of the
chain barrel l, and thus raises the load; m is a fly-wheel, by means of which
the reciprocating motion of the cylinder imparts a rotatory action to the crank.


AIR-PRESSURE ENGINES. 35
The last example we shall give of the application of Mr. Hague's patent, is
that of a tilting or powerful forge-hammer, which is raised by the atmosphere
º g
º º ! 4. 4-1- l, (+l º 4-l- * ~34 - C - 2 -
* * * * * * zºº. arº tº rvº are nº * * r * * * * arº ºra*, *r even
preSS}rig Upon & *::S:C: CCºncotcd. vº view axcºa aaaaa º a 5 V van v tiºn i v i 1 v 1.4 V, ** 14 kJ V ºf u \º Sºl UAV2
being rarefied by means of an air-pump situated at a distance,) and which falls,
by its own weight, upon the admission of the atmosphere above the piston.
si-
rºl
Tº
iſſilſ ;
º º
Q I gº
a b is the hammer turning upon a fulcrum at b, c the anvil; d a cylinder,
situated immediately over the hammer; e the piston, connected with the hammer
by the barf, and the slings g; h a slide valve, worked by the lever l, which is
struck by a pin on the barf, when the piston arrives at the top of the cylinder,
which depresses the valve so as to shut off the communication with the air-
pump, and admit the atmosphere, permitting the hammer and piston to fall
by their own weight. Towards the close of the descent, the hammer, by means
of a line attached to it and to the lever l, reverses the position of the lever l
and of the slide-valve, thus re-opening the communication between the cylinder
and air-pump. K is the pipe leading from the cylinder to the air-pump, and m
a cock for shutting off the communication with the air-pump when the hammer
is not at work; n n spanners for opening and shutting the cock.
Pneumatic Transport.—In the year 1824, the ingenious Mr. John Wallance,
of Brighton, took out a patent for a mode of employing the natural pressure of
the atmosphere, operating upon a partial vacuum, for the purpose of transporting
persons and goods with extraordinary rapidity from place to place. He proposed
to construct hollow cylinders of cast-iron, sufficiently large to allow carriages
with passengers and goods to pass through them. A series of these cylinders
were to be united, and extend from town to town, and the junctions made
sufficiently air-tight to admit of a rarefaction of the air within the tube, by the
continued action of powerful exhausting machinery at one end. The carriages,
which were to travel inside of this tube, were to be of the same cylindrical
form, and very nearly of the same transverse dimensions, so as to constitute, in
effect, pistons, which were to be impelled by the air rushing in at one end of
the trunk, to restore the equilibrium, or fill up the vacuous space mechanically
produced on the opposite side of the pistons. A model, on a sufficiently large
scale to test the efficacy of the principle and mode of action, was set up
on the patentee's premises at Brighton, and many persons were thus blown














36 A [R-PRESSURE ENGINES.
through the tube. Notwithstanding this demonstration of the correctness of
the principle, sufficient subscriptions were not obtained to carry the plan
into effect on a greater scale. A notion was very generally entertained that
the scheme, if feasible, could not be carried into practice on an extensive
scale, and at a cost that would repay the subscribers; to this circumstance may
also be added, a fear that the extraordinary mode proposed, of travelling in the
interior of a tube, would not accord with the taste of the public. The latter
objection has, however, been obviated by a novel arrangement of mechanism,
which has recently been the subject of a patent granted to Mr. Henry Pinkus,
whose invention consists in transferring the action produced upon a piston or
diaphragm, moving in the interior of a tunnel or tube, to its exterior, by con-
necting a vehicle or machine, (termed the dynamic traveller,) situated within
the tube, with a car or carriage without, (denominated the governor,) to which
the train of transport carriages are attached. A working model of this invention
is at present being exhibited in Wigmore-street, Cavendish-square; and a joint-
stock company, called “The National Pneumatic Railway Association,” is in
progress of formation; the avowed object of which is to carry the plan into
effect on all the principal roads of the kingdom. This singular mode of trans-
port having thus gained considerable celebrity, and the principle upon which
it is founded being essentially correct, we shall (notwithstanding the mechanical
difficulties apparently to be surmounted) introduce a brief description of the in-
vention under this head, reserving a more extended consideration of the subject
for the article RAILwAY. The pneumatic railway admits of several methods of
application, in each of which the dimensions, economy, and details, vary. On
a line of road where the transit is very great, as, for example, between Liverpool
and Manchester, a double line would be required, the cylinders of which, the
patentee states, should be 36 inches in diameter, and so moulded, as to be of
the average thickness of three-quarters of an inch; that is, the lower semi-
circumference to be three-quarters of an inch, and enlarged into a series of
rings three feet apart, so as to be 13 inch thick where the rings occur; thus
giving the lower semi-circumference an average thickness of seven-eighths of
an inch. The upper semi-circumference need not be of a greater average
thickness than five-eighths of an inch, when disposed into similar rings. On a
single line of road, where the transit is considerable, the size of the cylinders
may be increased to 40 inches diameter, and be of a proportionate thickness;
but when the pneumatic system is combined with a common railroad, that is,
laid between the ordinary rails, as a medium for transmitting motive power to
carriages running in the usual manner on rails fixed upon blocks, the cylinder
not having to sustain the weight or action of the loaded carriages, may be
reduced to 28 inches diameter, and half an inch thick: and when the system
is applied to draw or propel barges on canals, (which is also contemplated by
the patentee,) a cylinder of only 22 inches diameter, laid down in the towing-
path, he considers to be fully adequate. The length of the pneumatic tube
will be equal to the whole length of the railway or canal to which it may be
applied, and it should be cast in portions of the greatest length possible, in
smooth metal moulds, so that their inner sides should be very even and true,
and they are to be connected by the ordinary socket joint. Fig. 1 of the
annexed wood-cuts exhibits a perspective sketch of a portion of a line of
pneumatic railway, laid down, exhibiting the “governor’’ drawing a train of
carriages along it. The upper half only of the air tunnel a a is seen, the other
half being imbedded in a semicircular trench ; on the edges of which trench
rest strong projecting ledges, which are cast to the outsides of the tunnel, in a
longitudinal direction. These ledges are about three inches wide on their upper
surfaces, and constitute the railway upon which the wheels h h of the governor
or drag, and those of the train, run. To explain the mode adopted of com-
municating the motive force generated in the interior of the tunnel to the
governor on the outside, we must refer the reader to Fig. 2, which represents
a sectional perspective of a portion of the tunnel; wherein it will be seen that
a strong flat bar f is bolted to the governor, so as to depend vertically through
a longitudinal chase made in the top of the tunnel, and reaching to the centre
§
; t -
§ † º º
º
§: |
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W
º
| §§|| *
--
-->
sº: : º-º-º-º-º- --> * * *-* - E:...E.: :- F- º: ºr -
:::::::::::::::::::::::fffl Sº *::::=º::::::::::sº • *-* ~ *-es-, - - --ºw rºº -º-º-º: “”.
--~ * *
Perspective view of the tunnel only, with the lowermost half imbedded in the earth; the central portion of the figure being broken
away to show the pneumatic piston; its attachment to the dynamic traveller, and the connexion of the latten by the vertical bar f to the
governor, on the outside, seen in Fig. 1, at 9.







38 AIR-PRESSURE ENGINES.
of it. Here it is firmly fastened to a species of carriage, of the form of a velo-
cipede, which operates as a guide and stiffening-frame to the piston or diaphragm
c, that receives the impulse of the atmosphere; the expanding piston having a
conical steel ring around its periphery, one foot wide, and placed at an angle of
about 15° from the surface of the cylinder, against which one edge of the cone
acts with a slight pressure of the air, so as to conform to any slight inequality of
the cylinder. A more exact comprehension of these arrangements will be afforded
by the subjoined Fig. 3, which exhibits a transverse section of the pneumatic
==
Eº-
|
*
railway, an end elevation of the governor; its connexions and position; also
the rear wheel of the dynamic traveller; its position within the cylinder; the
guide rail (cast to the interior of the cylinder) on which it runs; and the piston
in advance, a a a is the cylinder, the lower semi-circumference of which is of
greater thickness than the upper, to enable it to withstand the greater strain on
this part, to which it is subjected by the weight of the carriages rolling, upon
the projecting ledges or rails b b; c ce shows the area of the piston strengthened
by cross bars; did d d stay rods, connecting, the piston to the frame of the
dynamic traveller, the hind wheel only e of which can be seen in this view...f
exhibits an edge view of the bar that connects the dynamic traveller to the
governor g, of which h h are the running wheels, connected by a cranked
axletree. In connexion with the vertical arm f are inflexible horizontal arms,
from which are suspended by pivots or vertical axles, anti-friction wheels i i,
whose peripheries roll on the outer sides of the longitudinal “hase, and keep
the vertical arm in the centre, so as to prevent its touching on eithe"

AIR-PRESSURE ENGINEs. 39
side. This figure also shows the shape of the longitudinal chase or aperture,
through which the connexion is made from the interior to the exterior; this
chase is cast with the cylinders, and is necessarily continued the whole length
of the tunnel. In order that the running wheels of the governor, as well as
those of the train of carriages that follow it, may be kept truly upon the centre
line of the projecting rails, and never rub against the sides of the tunnel, metallic
arms are projected from their frames, carrying anti-friction wheels, the peripheries
of which roll against the outer sides of the longitudinal chase and underneath
the flange; this latter circumstance affords a great security against upsetting.
And for the purpose of keeping the peripheries of these anti-friction wheels
always in contact with the chase, whatever curves may be made in the line of
railway, their axles turn in slots, and are pressed inward by springs. Into the
trough, an elastic flexible padded chain, called by the patentee, the valvular cord,
is fitted the whole length of the tunnel, forming, as it were, a continuous valve.
In the annexed figure, this valve is shown in section on a greater scale, with
Fig. 4.
the flexible cord l in its place. The sides of this cord, when not compressed,
have a curved figure, as represented by the dotted lines: it is surrounded with a
coat of felt, and on the top is attached a jointed band m of iron, resembling a con-
tinuous series of hinge-flaps, the joints admitting of the utmost pliability to the
cord, and affording a compensation for the expansion or contraction of the
metallic portion of the band; the other materials of the valvular cord are of too
soft and yielding a nature to require any provision against the changes of
temperature, and these are smeared over, or saturated with, unctuous matter, to
keep them soft and more effectually air-tight. By reference to Fig. 2 it will be
seen that the piston precedes the dynamic traveller in the tunnel; and by
reference to Fig. 1 it will be perceived that there is a small wheel in the centre,
(shewn also at k, Fig. 3,) with the valvular cord l passing over its periphery,
while there is another similar wheel in front, and a third at the hind part,
which constantly keeps the valvular cord in its trough. The office of the centre
wheel is, therefore, simply to keep continually lifting out the valvular cord from
its seat, and thereby expose the back of the piston to the full and direct action
of the proximate atmosphere; the fore wheel, by its pressure upon the valvular
cord, preserving the partial vacuum effected before the piston, and the hind
wheel, by its pressure, restoring the valvular cord to its previous station. To
enable the conductor to retard or stop the progress of the vehicle at pleasu e,
the patentee proposes to form a valve in the lower quadrant of the piston, to be
opened or closed at pleasure by means of a lever, or a chain and pulleys. With
a view to facilitate the operation of transit, and enable various parts of the same
line of the pneumatic tunnel to be used simultaneously, the patentee propo es
to divide it into sections, (of convenient lengths, which may be determined by
the stations of the operating engines,) by intercepting station valves, which may
be made similar in form and construction to the common gas valves usual w
applied to mains; and the connexion may, in this case also, be similar. The
patentee, however, prefers station valves of the nature of vertically sliding
shutters, running down into sills below the line of the tunnel, as these admit of
readier working than the gas main valves. Stationary exhausting engines, or
air-pumps, are to be put in action by attached local steam engines, or other con-
venient first mover; communications between the exhausting engine and the
pneumatic tunnel to be made by means of lateral tubes; and the connexions

40 AIR MOTIVE-ENGINES
are to be made in the common manner upon the lower side, at the distance of
about 200 feet from the station valve, .." on the side of it that lies nearest to
the station whence the governor, with its train of carriages, is to be drawn.
The stations for the engines may be at 3, 4, or 5 miles apart, according to the
power of the engines, the capacity of the pneumatic tunnel, the degree of
*arefaction necessary, the average weight to be conveyed, the velocity required,
and the height of any inclined plane to be surmounted. As the power to be
produced is by the pressure of the atmosphere acting against the piston, in
advance of the dynamic traveller, by the rarefaction within the tube before it,
the pressure will depend upon the degree of rarefaction; and that may be con-
stantly ascertained by means of barometers placed at the different stations,
which will indicate the approach of the governor and its train, and about its
distance from the station. A barometer placed on the governor, and commu-
nicating by a small tube with the interior of the pneumatic cylinder, and through
the piston to its vacuum side, will likewise indicate the degree of rarefaction,
and, consequently, the pressure upon the piston, the sufficiency of power to
propel, and the time for moving off. Action being given to the exhausting
engines connected with the section of the tube through which propulsion is to
be effected, the station valve being closed, and the air abstracted from that end
of the section of the pneumatic cylinder, rarefaction will take place throughout
the whole of the included atmosphere contained in the space lying between the
station valve and the piston, which is attached to the dynamic traveller. The
partial vacuum thus effected at the station will cause the included column of
air to move rapidly towards it; and the incumbent atmosphere pressing upon the
valvular cord, will tend to aid the action of the weight of the cord in making
the pneumatic valve sufficiently close to prevent the ingress of the external air,
and preserve the required degree of rarefaction on the vacuum side of the piston.
The unincluded atmosphere rushing into the cylinder through the aperture in
the pneumatic valve over the dynamic traveller, (which is laid open by the lifting
of the valvular cord over the central wheel of the governor, as before mentioned,)
and impinging on the plenum side of the piston, will produce a pressure pro-
portional to the degree of rarefaction on its opposite side, and consequently draw
the train of carriages connected thereto after it. On the near approach of a
train to a station valve, the latter will be quickly let down into its recess, to
allow the former to pass. The valve may then be again raised; and the same
º continuing to abstract the air, as before, from the same section of the
railway, it will be again soon prepared for another train in like manner; while
the train that had passed into the next section is being operated upon in like
manner by the engine belonging to it, and so on, from one section to the other,
throughout the whole line of railway. For further remarks on this interesting
proposition, we must refer the reader to the article RAILwAY.
AIR MOTIVE-ENGINES. It has been already explained that air expands,
or has its elastic pressure increased by the application of heat, and that its
volume contracts, and its pressure becomes less, by a decrease of temperature;
and several attempts have been made by taking advantage of this property of
air, to substitute it for steam, as a prime mover of machinery. Could this be
effected, it would be a great advantage in many situations; as, for instance,
where water is scarce, or in steam vessels or locomotive engines, where (the
machinery forming a part of the load,) it is desirable to reduce the weight as
much as possible. Having said thus much of the principle of these machines,
we shall proceed to describe one or two of the latest arrangements for the purpose.
The first we shall notice is Messrs. R. & J. Stirling's air-engine, for which
those gentlemen obtained a patent in 1827. This machine resembles the steam-
engine in the construction and application of many of its parts, such as the
pistop and cylinder, reciprocating beam and parallel motion, crank, and fly-
wheel, as shewn in Fig. 1. Motion is communicated to the piston in the cylinder
by alternately heating a portion of air connected with one side of the piston,
and at the same time cooling that in connexion with the other. This is effected
by means of the air vessels a a, one of which communicates with the upper
part, and the other with the lower part of the cylinder, through curved nozzles,
AIR MOTIVE-ENGINES. 4]
Fig. 1.
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w nose sides are cylindrical, and top und * & W. H. . . & fºr * f ; f r
ls made of cast-iron, and supported in the brick-work by the projecting ledge























42 AIR MOTIVE-ENGINES.
l l, is furnished with a plunger c C c. The top and bottom of the plunger is
made of strong sheet-iron, perforated with very numerous small holes to admit
the air. The interior of the plunger is filled with very thin plates of sheet-iron,
so bent as to prevent their flat surfaces from coming in contact, that the air may
have a free passage between them. These are also perforated with small holes,
which holes are not placed opposite to each other, but so arranged as to cause
the air to pass through the plunger in a zig-zag direction. The plunger is
formed circular, to fit the top and bottom of the air vessel when drawn up and
down. The rim c c of the plunger, which moves in a cylindrical receptacle at
he circumference of the air vessel, as represented, is not perforated as the other
part. It is kept steady by a spring at l l, consisting of a belt of thin sheet-iron,
attached at its upper edge to the rim ce; a number of slits are made at the lower
edge of the belt, to admit of its being bent outwards to rest against the air vessel,
and act as a spring. The plunger is also kept steady, in its ascent and descent,
by the plunger rod d passing through the stuffing-box at the top of its case, and
by the guide-rods gg, which work in the guide cases i i, Figs. 1 and 2. The
guides are fixed to a ring h h which is attached to the plunger and the plunger rod
by the arms ff, four in number. The guides are supplied with oil by the oil-cup
and stop-cock at the top of their cases. The top ee of the air vessel is flanged down
in the manner represented at k, with a thin ring of sheet lead between the flanges,
to keep the joining air tight. The lower part of the air vessel is heated by a
fire placed under it, and its upper part kept cool by a current of cold air, by
water, or by other means. The plunger rods of the air vessels a a Fig. 1, are
attached by slings to the end of the beam v, so that the motion which elevates
bne plunger in one of the vessels, depresses that in the other. When the plunger
s raised, the cold air in the upper part of the vessel will be heated in passing
through the interstices of the plunger in its ascent, which has itself been heated
on reaching the hot or lower part of the air vessel; and during this time the
air in the other vessel will be cooled by passing through the interstices of the
plunger in its descent, which has itself been cooled by reaching the cold or
upper part of the air vessel. These changes of temperature are further augmented
by portions of the air being alternately changed from the hot to the cold and from
the cold to the hot parts of the vessels, by the alternate occupation of the hot
and cold parts by the plunger. Now, as one of the air vessels is connected with
the top and the other with the bottom of the working cylinder, there will be
a motion produced on the piston by the alternate application of the expansive
force of heated air : and this motion is communicated to the beam v through
the piston rod and parallel motion, and joins the beam to the fly-wheel ss.
On the axis of the fly-wheel is fixed an eccentric t, which communicates motion
to the plungers in the air vessels through the system of levers 1, 2, 3, 4, and the
beam v, and this motion is adjusted so that the change of the plungers shall be
effected whenever the piston reaches the top or bottom of the cylinder; thus
applying to that end of the cylinder where the piston is, the hot air, which, by
its increased elasticity, will drive the piston to the other end. This engine is
also furnished with an air-pump, the piston rod of which is shown at ar, for
condensing the air into the reservoir w w. The air is permitted to pass through
self-acting valves into the curved nozzles, and thence into the cylinder, or the
air vessels a a, but is not permitted to return from these vessels or the cylinder
into the reservoir w w ; which is also provided with a safety valve for the escape
of superfluous air, when more is pumped in than is necessary to supply the air
vessels. The air-pump is only occasionally required to be set to work.
In 1828, Messrs. Parkinson and Crossley took out a patent for an air-engine,
which differs considerably in the arrangement of its parts from the one just
described; and as it appears to be of a somewhat simpler construction, we shall
lay a description of it before our readers. Fig. 1 shews a front elevation of so
much of the engine as is necessary to explain the invention. Fig. 2 is an end
elevation, and Fig. 3 a section (upon an enlarged scale) of a differential vessel
and its transferrer, exhibiting also a mode of heating and cooling the differential
vessel. The same letters in each figure where they occur, refer to the same parts.
The differential vessel a a is of the form of a hollow cylinder with convex ends,
AIR MOTIVE-ENGINES. 43
of such a length as to preserve an essential difference of temperature between
one end and the other, and neariy one-haifiyeing exposed to a not, and the other
half to a cold, medium. The vessel has a stuffing-box at the end f. and at the
other end is an opening or pipe l m or l n, for the purpose of forming a com-
Fig. 1
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munication with the working cylinder and piston. The transferrer b b is a hollow
vessel, air tight, and so much shorter, as to leave a sufficient space in the dif-
ferential vessel for containing a volume of air, which, when expanded by heat
passing through the pipes l m or lºn, will also fill the working cylinder, and force
the piston from one end of it to the other. The transferrer is also made only
so much less in diameter than the differential vessel as to allow it to move freely
from one end of the differential vessel to the other. To one end of the transferrer
is fixed a rode, passing through a stuffing-box f. for the purpose of moving it
from one end of the differential vessel to the other, thereby causing the air to
pass in a thin stratum against its hot and cold parts alternately thus producing

44 AIR-MOTIVE ENGINES.
the force or power to be employed against the working piston. The rod g, Fig. 3
which is fixed on the upper part of the differential vessel, is intended tº guide
the transferrer in its proper 㺠by means of a tube which is inserted in
the upper end of the transferrer, the lower end of the tube being made *.
tight. Motion is given to the transferrer by means of the eccentric o in the
ºu.ii. º.º. i.i.d.; -
shaft p being connected with the beam r, which beam is connected to the rod
e of the transferrers by the links ss. The working cylinder u with its piston,
side rods, cranks, shafts, fly-wheel, and eccentric motion, are the same as those
commonly used in steam-engines, and therefore require no particular description.
The pipe l m forms a communication between the differential vessel, No. 1, and
the top of the cylinder; and the pipe l n connects the differential vessel, No. 2,
with the bottom of the cylinder. The operation of the engine will be as follows:
Supposing the eccentric disconnected from the beam r, and the upper part of
the differential vessels heated, and their lower parts cold, and the transferrers of

AIR-MOTIVE ENGINES. - 45
the two differential vessels placed by halid in thc sittiations showii iii the figure,
and the volume of air occupying the hot part of the differential vessel, No. 2,
and being increased in elasticity in º to its temperature, whilst the
volume of air in the differential vessel, No. 1, is occupying the coldest part, the
working piston will be forced upwards by a power corresponding with the dif-
iſiä
|
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|
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ference of the elastic force of the air in the two differential vessels; and when
the working piston has been forced to the top, the situation of the transferrers
should be reversed by hand, so that the air in the differential vessel, No. 1, will
occupy the hot part, and communicate its force to the upper side of the working
piston, and thereby produce a returning stroke; and the eccentric being then by
hand re-connected with the beams, the alternate expansion and contraction of
the air in the two differential vessels will keep the engine in motion; and then,
by working the transferrer in the same way as the valves in steam-engines, the
engine may be either stopped or put in motion. For the purpose of heating the
differential vessels, the inventors prefer the employment of inflammable gas, a
mode of applying which is shewn at Fig. 3, where d d is a hollow ring, sur-
rounding the differential vessel, and communicating with the tube by which the
gas is supplied; this ring is perforated for the emission of jets of gas, to flow,
when ignited, all round and against the differential vessel, or nearly so; c. c is
an iron vessel, for directing the heat to the differential vessel, which casing is
open at bottom for the admission of air, having also an opening at top, to serve
as a chimney or flue; k is an outer covering of polished metal, of about two or
three more inches in diameter than the casing c c, for the purpose of lessening
the radiation of heat. The working cylinder h may be kept hot by means of a
current of heated air being conducted to it from the flues of the differential
vessels. t t represent the differential vessel placed in a cistern of cold water,
with a constant current running in at the bottom u against the differential vessel,
and passing off at the top v. We are not aware that the engine just described
has been brought into practical operation, but that invented by Mr. Stirling was
employed in a stone quarry; it has, however, we learn, been replaced by a
steam-engine, in consequence of its inferiority to the latter in the economy of
G

46 AIR STOVES.
working, particularly as respects the consumption of fuel. One objection to air-
engines is, that the changes of volume do not take place with sufficient rapidity,
and that when water is employed to accelerate such changes, the quantity
necessary for that purpose is greater than would be required to supply the boiler
of a high-pressure steam-engine; so that in situations where either water is
scarce, or the weight of it an objection, the latter engines would, on those
accounts, be found superior to the former.
AIR STOVE. A stove, the heat of which is employed to heat a stream of
air directed against its surface, which air is then admitted to the apartments
requiring to be heated. The principle of the construction is, to inclose the stove
containing the fuel in a casing somewhat larger than the stove, so as to leave a
space of a few inches between them. At the lower part of the casing is an
aperture filled with a register to regulate the admission of the air, and at the
l.
upper part is a similar opening to allow of its exit. When the air-stove is not
fixed in the apartment which is to be heated, a pipe is fitted to the upper aper-
ture of the casing, to convey the air to the apartment. The construction ;
be varied to suit circumstances; the above cut is a representation of one whic
has been used with very good effect to heat the Infirmary at Derby. It is upon
a plan which was first introduced in this country by Mr. Strutt, of Derbyshire,
who employed it for the purpose of warming his extensive cotton works more

A : R STOVES. 47
uniformly and with greater economy than formerly. Fig. 1 is a section of the
air-stove and cockle; and Fig. 2 a transverse section of the stove, exhibiting the
disposition of the masonry surrounding the cockle, a, the cockle, is made of a
cubical form, with a dome, or rather a groined arch top, about 3 or 4 feet high,
and is made of plate or wrought iron about # of an inch thick, riveted together
like the ordinary boilers of steam-engines. The smoke passes off by a narrow
passage at b, at the base of the cockle into the flue c, jº leads to the chimney.
The brick-work surrounding the cockle is built with alternate openings, as
represented in the side view at f at about 8 inches distant from the sides of the
cockle. Through these apertures pipes are inserted which may be made either
of sheet-iron or of common earthenware, so as to extend within an inch of the
cockle, by which means the air to be heated may be thrown near, or in imme-
diate contact, with the surface of the cockle if desirable, which was found by
Mr. Strutt to double the effect derivable from the same quantity of fuel. The
horizontal partition of the air chamber at d cuts off the communication between
the lower and the upper half of the chamber. The arched openings in the lower
half g g exhibit the openings of the main air flues leading from the exterior
atmosphere. The air passing from these lower flues g through the apertures
beneath the horizontal partition d d, and coming in immediate contact with the
body of the stove, must find its way into the upper air chamber h, through the
numerous apertures or pipes in the upper division, by which circuit its velocity
will be retarded sufficiently to obtain the necessary elevation of temperature
from the heated cockle. In order that the air may not be injured for the pur-
poses of respiration, the size of these Belper stoves, as they are called, must be
so regulated as not to heat the cockle or body of the stove at an average above
280° Fahr., or according to Mr. Sylvester, or 250° according to Mr. Tredgold,
when the air is intended to supply living rooms; but for drying rooms more
heat may be given, if the saving of time is an object; but still it is far more
economical to dry at a lower temperature. From the upper, or hot-air chamber
h, a main flue i leads to each of the floors to be heated. The horizontal and
inclined parts of these main flues should be made of brick or stone, and if they
have to pass under ground, should be secured in a case. The vertical parts may
be of sheet iron, or even of well-seasoned wood. An opening over the door of
each room allows the entrance of the heated air into it, and a flue from the
bottom of each room proceeds to the roof of the building, from whence the
whole of the air is discharged by a turncap, the mouth of which is kept con-
stantly from the wind by a vane. Provided a stove of this construction is well
built, and so managed as not to allow the heated air to attain too great a tem-
perature, it is not only much more economical than any other mode of warming
extensive buildings, but it is equally salubrious with the more recent method of
employing steam pipes for this purpose, if not more so. As the air passages of
this kind of stove ought to be several feet under ground, it affords also a con-
venient mode of admitting a portion of cold air to the interior of the building
in the summer season, as well as supplying heated air in the winter. The
change in the temperature of the air by passing in this way, Mr. Sylvester says,
is greater than could be supposed. The cold air flue at the Derby Infirmary is
about 4 feet square, and its length 70 yards. . In the month of August, when
the thermometer in the shade stood at 800, the air which entered the air flue
underground at the same temperature, was found to be 600 at the extremity
where it entered the stove-room; the current at this time was sufficient to blow
out a lighted candle. In another experiment, when the outer air was 549, this
air was reduced to 510 by passing through the flue. This is a great advantage
of the air stove above the use of the steam apparatus, since this last only supplies
the deficiency of heat in winter, but has no tendency to check it when the tem-
perature of the atmosphere is beyond the mean temperature of the earth. But
although close stoves, and air stoves in particular, are decidedly more effective
and economical than open fire places, still the prejudice is so strong in England
in favour of the latter, from their more cheerful appearance, and their freedom
from any unpleasant and confined smell which is apt to arise from stoves when
they become highly heated, that there seems but little chance of the latter
48 AIR STOVES.
superseding the former. It is therefore desirable, if possible, to derive from an
open fire-place a portion of the advantages of an air stove, and accordingly, many
combinations with that object have been devised. The following one is by
Mr. Ricketts, of the Strand; besides the grate, it comprises an oven, boiler, and
hot air chamber, all heated by one fire, without flies. No. 1 represents the
range, as fixed; No. 2, the hot air chamber distinct; No. 3, a vertical elevation
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of the same chamber: the same letters in each figure refer to similar parts, a
the hot-air chamber; b cold-air drain, or aperture, at bottom of the chamber ;
c thin iron plates or ribs 2} inches wide, to direct the passage of the air against
the heated back of the chamber, producing a current of hot air which may be
communicated by pipes to any part of the building; f conducting oven, heated
by an iron knob g; h an iron boiler to which the steamers may be applied.
It has been mentioned, that stoves are liable to the objection of sometimes
causing an unpleasant sensation from the air becoming over-heated, or, as it
is termed, burnt. This may be obviated by heating the air destined to circulate
in the apartments by steam, instead of employing the direct action of the fire.
An apparatus of this description, patented by Mr. Stratton, is shewn in the
following figures. Fig. 1 is an elevation, and Fig. 2 a section of the apparatus.
It consists of an exterior tube of copper a, Fig. 2, within which is a smaller
tube b of equal length, soldered to end plates c c, forming thereby a steam-tight
vessel, surrounding the interior tube b. d d is a spiral apparatus of copper,
coiling round the upright rod e : the periphery of this spiral exactly fits the
interior tube b, so that no air can pass up or down without taking a winding
course through the spaces formed by the spiral. f is a semi-globe of copper,
perforated with holes; and g g are two moveable plates, in which are cut
oblong apertures, so that when the holes in each coincide, the air has a free
passage through them ; but when they are moved by the lever h, so that the
holes in one are covered by those in the other, the passage is stopped, and the


AIR STOWES.
49
- - - - - - i is a steam
pipe, for the purpose of admitting
steam from a small boiler; and j
is another pipe, for allowing the
water formed by condensation to
run back into the boiler or else-
where. Steam being admitted into
the compartment formed between
the two tubes by turning the cock,
instantly heats the interior tube
b, and (by radiation) the spiral
d d, by which the air already
filling the tube is expanded, and
rises by its diminished gravity,
escaping into the open atmo-
sphere through the holes in the
cap f. The air underneath rushes
in to fill the partial vacuum, and
in its turn becomes heated; by
this means a constant current can
be kept up so long as the com-
partment is supplied with steam;
but this current would, in an un-
impeded passage, be much too
rapid in its motion to become
sufficiently heated for the pur-
pose intended. The spiral d d
is therefore introduced, which
causes the air (as we have said)
to take a winding course, and
thus traverse the whole heated
surface of the spiral before its
exit into the air. By this con-
trivance the air is made to traverse
over a considerable surface of
heated material, while the steam
required to act therein is confined
to a very short vessel, and, con-
sequently, has but a small portion
of its surface exposed uselessly.
It may be cased in wood or other
non-conducting material, if de-
sired, for ornament or any other
reason, without any diminution
of its effect in warming the apart-
ment.
The following simple and in-
genious air stove is the invention
of Mr. Perkins, of Fleet-street,
and the engraving represents a
stove upon his plan, which was
put up on the premises of Messrs.
Coe and Moore, printers, Old
Change. Fig. 1 represents the
stove, flue, and building, in which
it is fixed. Fig. 2, a continuation
of Fig. 1, on a smaller scale, ex-
tending it above the roof of the
building. The letters of reference
designate similar parts in each
*
|
º
|
º
|
|
|
|
|
Illſlållililuliſrulu
hillilullulº
|
|
|||||||||||||I|| –
|
|
|
º
!
s
-


50 AiR STOVES.
figure. The stove a is of a cylindrical form, fixed vertically in the brickwork
it is closed above by the lid b, which is removed as often as may be required to
supply the stove with fuel (coke is pre- ~~~~\-ſºuſsº
ferred). c c is the flue, which is a tube i †
of wrought iron, excepting that curved ;
portion immediately connected to the
furnace cylinder, which is of cast iron.
d is the ash pit. At i is an elliptical
aperture, for the supply of air to the
fire, which may be admitted in a greater
or smaller volume by wholly or partially
removing the cover k. l is a furnace
door, for affording convenient means
for clearing out the ashes. The grating
on which the fuel is laid, is not fixed,
as usual, immovably in the brick-
work, but is connected to the frame by
hinges on one side, and held up on
the other by a cross-bar, which rests on ,
a button m. This button being turned
one quarter round, the grating imme-
diately falls as a trap door, discharging
all the fuel into the ash-pit, by which
the fire is almost immediately extin-
guished without trouble. The stove is
placed on the floor of the basement or
cellar, which is kept thoroughly warm
and dry, so as make it a good
store room for paper, although it is
under ground; from thence the flue
ascends through the ground floor n,
the first floor o, the next floor p, and
passes through the roof, as shewn. The
flue for the smoké c c c is surrounded,
as shewn, by a larger tube, at about 3 = -
:
|
-
--
wºn
Él
=:
|
:
#
---
-rd
:
e % ST- g|H=H
inches apart, for the conveyance of % § #| H
heated air to the several apartments. #| EH
To effect this, cold air is freely admitted
through a large aperture r in the wall,
which enters the chamber s, and im-
pinging upon a strongly heated surface,
it immediately acquires a much higher
temperature. To increase this effect,
the curved cast-iron neck of the flue
adjoining the stove is considerably flat-
tened or expanded, so as to expose to
the ascending column of air a more
E
=
H
É
-:
#
=l
-
==
l
H
|
=l:
-:
extended surface of heated metal. The # *E
e :-- º l |
caloric given out by the burning fuel, #
instead of being chiefly carried off by |
the flue, as in ordinaly stoves, is rapidly H.
abstracted by the current of air, which Íñí
air, thus heated, may be wholly or par-
tially given out into any one apartment,
|
fºc-—º Tºº EA Agrº
tºgºrº-3
or distributed in the several apart- if
ments, as may be desired (either for #
g º #dº
drying the printed sheets, or for warm- #
ing the persons at work,) by a few sim-
ple valves, or registers. These registers are made of two separate annular
plates, sliding circularly on their flat surfaces one over the other. The lower













A [R TRAP. 51
one is fixed by rivets to the sides of the external tube, and the upper Güe fies
on the lower one, and is made to slide over it by moving to the right or left a
small handle, which projects horizontally through a slot mortice in the external
tube. The size of the interstices in these plates is both alike, as shewn in the
separate Fig. u. By these registers, it will be seen that the whole of the hot
air may be confined to one apartment, or distributed over several. The aper-
tures through which the heated air flows into the rooms, are 10 or 12 inches in
diameter, and each one is provided with a cover like a saucepan-lid t, to prevent,
at pleasure, the hot air from entering any particular chamber. In the upper.
most floor the flue of the hot-air tube terminates at w, about 3 feet above the
floor; from thence the smoke flue alone ascends, which first rises a few feet,
then takes a horizontal course, and afterwards passing through the roof, the
upper extremity is provided with a canopy or cowl to keep out the rain, and to
prevent the Smoke from being forced downwards by sudden gusts of wind.
The premises before mentioned are thoroughly warmed throughout the winter,
at as high a temperature as is consistent with the comfort of the persons
employed therein, at an expense of less than nine pence per day for fuel. But
one of the chief advantages that result from this apparatus, is the convenient
and facile manner by which the heat can be augmented to the required degree
in any apartment, for the purpose of quickly drying the freshly printed sheets
of paper, an advantage evidently of the first importance to printers, as it enables
them to print their work with extraordinary despatch. But when a stove of
this kind is not employed for drying moist substances, the hot air should be first
brought into contact with a vessel of water, to render the air sufficiently humid
for healthful respiration.
AIR BEDS. A bag of the size of a bed, divided into several compartments,
and rendered air-tight by a composition, of which caoutchouc, or Indian-rubber,
forms the greatest part. This bag may be inflated by bellows, a syringe, or any
other means, and is furnished with stop-cocks to retain the air or let it out at
pleasure. These beds will be found cztremely convenient to travellers, espe-
cially in warm climates, from their portability, and not being liable to vermin;
also to invalids, from their perfect elasticity, which may be regulated at pleasure
by an attendant, without disturbing the occupant.
AIR WESSEL, IN HYDRAULics, a contrivance to continue
the flowing of water after the impelling force has ceased to
act, as in the return stroke of a forcing-pump, or in Bra-
mah's hydrostatic press, thus preventing the shocks which
would arise from the sudden stoppage of the water whilst
in motion, and also avoiding the loss of power in moving
it from a state of rest at each effective stroke. It con-
sists of a vessel containing air, which is placed between
the delivery valve and the mouth of the delivery pipe,
and the water being forced through the pipe faster than
it can escape at the orifice, rises in the air vessel, com-
pressing the air therein with a pressure proportionate to
the pressure on the delivery valve. On the return stroke,
when the piston ceases to act, the air expands and continues
the flow of water until the pressure of the air is only equal
to the pressure of the column of water between the air
vessel and the mouth of the delivery pipe. See the cut,
in which a is the air vessel; b a flange by which it is
attached to the delivery pipe or main; and c the exit
II}{2.
p 'Air TRAP. A contrivance for excluding the effluvia arising from drains,
&c. The most simple and effectual trap for this purpose consists of what is
termed a water joint, which may be variously arranged. Fig. 1 represents the
construction commonly adopted for sinks in kitchens, &c. a is the pipe leading
to the drain, the upper end passing through the bottom of a small metal cup
b, the rim of which rises somewhat higher than the top of the pipe, and is
cemented or soldered into the sink. Over the mouth of the pipe is inverted a cup

52 ALARUMS
e somewhat smaller than the other, and descending to
within a short distance of the bottom of b, and on
the top of this is fixed a strainer to prevent the pas-
sage of substances which would choke the pipe. Now
as the water in passing off by the pipe will always
leave the cup b full up to the top of the pipe, the cup
c will always be immersed to a certain depth in the
water, which will effectually prevent the escape of foul
air from the pipe a, for air being lighter than water,
cannot of course descend through it. Fig 2 repre-
sents an air trap, which, instead of being made of
metal, is fabricated of the common red pottery, and is particularly adapted for
falling into a course of the “ º Fig. 2.
quarries,” used in many parts of the SN $ §
country, which are cleansed by washing º T-AA+º
and sluicing them with water. In its
superfices it presents a square of 9 inches,
the same as the ordinary quarries. a is b sº
It will º
§
the grating; b the trap frame.
be evident no foul air can pass up the
grating, as the only passage for it is
through the water, over the stop c, and =4 Ns NAA
under d.
AIR PIPES. An invention of Mr. Sutton, a brewer, of London, for ven-
tilating the holds of ships, and for drawing out the foul air which arises from
the bilge water, and collects between the timbers. A pipe proceeding from the
lower part of the hold is brought up to the ash-pit of the ship's coppers or
other fire-place, and the air becoming rarefied by the fire above it, it ascends,
and its place is supplied by the external air rushing into the hold through the
interstices between the timbers, or by pipes descending for that purpose from
the deck to the hold.
AJUTAGE. The tube or mouth through which water is discharged. On
the forms of these depend in a great degree the force and velocity of the motion
of the fluid. See HYDRODYNAMICs.
ALARM, or ALARUM, is a term applied to a variety of instruments con-
structed for the purpose of producing sufficient sound or noise to awaken a
person from sleep, or otherwise to give notice of some occurrence, or warning,
of the state of the time, &c.
Glenny and Darby's Fire and Burglary Alarm. The object of this invention,
for which a patent was taken out in 1820, is to indicate by means of a placard
or signal, containing the written information, in what part or situation of the
premises to which it is attached, a fire or burglary has taken place, immediately
upon either having happened. This is effected by placing an alarm-bell within
a box, (having the appearance of any article of furniture,) the internal
mechanism of which is connected by lines or wires to every part of the premises
deemed to be hazardous. These lines, carried from the alarum in the manner
of bell-wires, are at their extremities connected to triggers, any one of which
being discharged, releases its line immediately, and sets off the alarm-bell
within the box, firing a pistol also, if attached thereto; and at the same time,
causes a slider or label to be presented, containing the words, “Fire,” or
“Thieves,” in such a part of the premises, describing where, and which of the
two occurrences. The construction of the apparatus is as follows: A box of
any external appearance, placed in the bed-room or elsewhere as a piece of
furniture, contains the alarm-bell, which is connected to the striking part of a
clock. Each of the lines before described, are connected at one end to a piece
of metal as a trigger, which is hooked to a hold-fast, placed in such a situation
that, by the opening of a door or window, the trigger is liberated, and the line
which passes over the pulleys placed at every angle, is drawn back by the other
end being attached to a weight inside the box; the weight in descending strikes
against a lever formed by a projecting pin, fixed to, and turning on, an hori-





ALARUMS. 53
zontal axis. This axis carries a series of lever pins, corresponding with the
number of lines, weights, &c. employed; so that any one of the weights by
falling, causes the axis to turn, and by means of an arm projecting from the
axis, a wire connected to the striking part is pulled, and the alarm set off. The
labels or slides before mentioned are each connected by a line or chain to its
respective weight, which, on its descent, projects or draws out to view the label
conveying the required information. In adapting this apparatus to indicate the
occurrence of fire, small lines of catgut, or threads of sufficient strength, are
substituted for the before mentioned lines, which are carried across the ceilings
or round the cornices of the apartments to be guarded. Some one of these
slender strings, it is considered, would be soon burnt by the ascent of the flame,
and give early notice of the destructive element, by the alarm bell to which it
was attached being put in action, which would at the same time indicate the
situation of the fire. Prior to the granting of this patent, many of the mechanical
arrangements described under it were in use, and the patentee's claim to inven-
tion may be considered as limited to the introduction of the direction labels,
which, in a large building, might prove of eminent use.
Russell's Fire Alarum. This apparatus is put into operation by the expansion
of a small quantity of air contained in an instrument called a pulse glass, which
consists of two bulbs, with a small tube of communication between them. Into
this vessel is put some liquid, usually coloured, so as to about half fill it, the
remaining space being occupied by air; it is hermetically sealed. This instru-
ment is so extremely sensible of a slight increase of temperature, that on placing
merely the hand upon one of the bulbs, or by gently breathing upon it, the liquid
is rapidly forced out through the tube into the other bulb, owing to the expansion
of the air within that bulb to which the warmth is applied, and producing an
apparent ebullition in the liquid by the bubbling of the air through it. When
these bulbs are equipoised upon an axis placed midway between them, it is
obvious that the liquid flowing into either bulb will cause it to preponderate;
and to obtain from this preponderating action sufficient force to set off an alarum,
Mr. Russell contrived the following arrangement, a represents one of the glass
bulbs, nearly filled with the liquid, which should also fill the tube of communi-
cation up to the opening into the bulb b; the whole of this vessel is enclosed in
a cavity cut out of a block of wood, except a portion of a, which is exposed for
the purpose of being influenced by an increase of temperature. The block
turns freely upon a centre or fulcrum at c, fixed upright in a stand d. e is a
long mortised lever or tube, containing four leaden balls, so placed over the
fulcrum as to rest in equilibrio. Upon heat being applied to the bulb a, the air
above the liquid rapidly expands, and drives it into b; the weight being thus
increased on that side, causes the lever to descend in the direction of the line f,
while at the same instant the leaden balls suddenly roll down the inclined plane,
accelerating the descent of the lever, and impart to it a considerable degree of
force, which it is evident may be almost indefinitely increased by lengthening the
lever, or augmenting the rolling weights. As motion is thus produced, attended
with great power, its application to the ringing of a bell, or any number of
them, or the firing of a gun, may be easily understood, all that is required being
a crank, with a wire connecting it to the alarm used. If a water pipe and stop-
{{

54 - ALARUMS.
cock were attached to the fulcrum of the lever, the plug of the latter would
thereby be opened, and the floor underneath be deluged with water.
Colbert's Fire Alarm. This consists of a column of mercury in a tube, with
a floating piston, which ascends and descends as the mercury expands and con-
tracts. A rod from the piston is connected at its upper end to a lever, which,
on being raised, releases a click or detent, and discharges the alarm. The
apparatus is provided with a dial plate and index, pointing to the degrees of
heat, which is to be adjusted to a few degrees of heat above the temperature of
the atmosphere, or above the utmost height to which it is expected the mercury
might rise from natural causes during the night. . It is enclosed in a case of
open fret-work, for the purpose of readily transmitting the heat, and is to be
deposited in the well of a stair-case, or other desirable place.
Congreve's Fire Alarm. The late Sir William Congreve suggested the em-
ployment of two metal plates placed in contact, with a cement between them,
that would melt at a low temperature. These plates were to be suspended by a
thread to opposite corners of a room, when it was considered that a slight
increase of heat would melt the cement, cause the plates to fall asunder,
and discharge the alarm. If the reader will refer to the experiments detailed
under the article ADHESION, he will find abundant reason to doubt the certainty
of the ready separation of the plates under the circumstances mentioned; and
he will then probably give the preference to the following suggestion of our own.
Provide a common house bell and spring. To that end of the spring by which
it is fixed to any object, tie a short piece of tape, sufficient to reach, when ex-
tended, only half way to the bell; and to that end of the spring next to the bell tie
another piece of tape of the same length as the former. Then compress the spring,
so that the tapes can overlap each other, and insert between them a piece of
wax, (made of equal parts of common resin and bees' wax) which may be com-
pressed together by the fingers. The overlapping may be to such an extent as
will cause the wax to soften and the tapes to separate, on applying a heated
atmosphere to them of about 100° Fahr., when the elasticity of the spring will
produce the required clattering of the bell.
We shall now proceed to give a few examples of alarums for giving notice of
the arrival of predetermined periods of time, by means of easily constructed
mechanism, referring the reader to CLocks AND WATCHEs for those of a more
J’
elaborate nature. The above figure represents a watch alarum, which the
inventor states he has made several of, and that they answer extremely well.
In a solid frame of wood p q about 8 inches by 4, and I thick, is inserted a
metallic rod, bent into a right angle at b, to which are attached a small rod k,
and two fixed pulleys d e. f is a cylindrical piece of wood, having inserted at
one end the pipe of a watch key, by which it may be made to rest on the pivot
of the watch, (the watch being sunk a little into the frame,) and turns with the

ALARUMS 55
minute hand, and at the other, a pin which keeps it steady by passing through
a hole in the rod k. A thread which is fixed to the piece f, and may be rolled
round it, passes under the pulley e over d, and round the moveable pulley l, to
which the weight wis attached; and being brought through a hole in the rod b c
is fixed there by the pin g. This pin is used to regulate the length of the thread
so that when it is completely wound off the cylinder f, the weight w may rest
on the plane h, which is moveable on a pin at ºn. The bell is fixed to one end
of a long spring r s t, the other end of which is fastened to the board at r, at
t is fixed a string, which keeps the bell in the position represented in the figure,
by means of a bit of wood o inserted into two notches, one in the plane h, and
the other in the horizontal part of the frame n ; the friction of the bit opre-
venting the plane h from falling. It will be easily perceived that by winding
the thread a certain number of times round f, the weight w will be raised to a
height from which it will take it so many hours to descend to the plane h, and that
when it does reach that plane and press upon it, the bit owill be released from
the notch, and the elasticity of the spring will make the bell ring with consi-
derable violence.
An improved mode of releasing the bell, described in the foregoing plan, is
exhibited in the subjoined diagram, wherein the parts are drawn upon a larger
scale. In this figure the bit of wood o is supposed to be tightly pulled by the
string attached to the spring of the bell, its lower end being detained by a fixed
piece b b, and its upper end held by a bent piece of brass, which turns upon a
centre at c c, and whose other end sustains the plane h by pressing against the
piece a a. The descent of the weight depressing the plane h, causes the bent
piece of brass to swing loose and release the piece of wood which is connected
to the bell.
The annexed figure represents
a watch alarum that is sold in
the shops of London, and which
we have seen perform with con-
siderable accuracy. The expense
of it is only seven shillings. a a
is a turned mahogany stand; b
the watch laid in a velvet cush-
ioned cavity adapted to receive
it, and placed in such a position,
that the hour at which a person
may wish to rise, shall be placed
opposite to a fixed index c. A
fine line, consisting of a single horse hair, with a loop at the end of it, is then
laid into the notch of a guide piece d, and the loop is then slipped over the hour


56 ALBUMEN.
hand of the watch. At e is a light ivory lever; to this the horse hair is tied
about midway of its length, with a weight f suspended to its lowest end. The
bell g, fixed on its steel spring, is then brought into the position shown by the
line h, the extremity of which line is provided with a brass wire hook, then
passed over the extremity of the lever, and put on to the upright pin i. When,
by the process of time, the hour hand has arrived at the period proposed, which is
opposite to the point of the index, the horse hair slips from it, the little weight
thereby becomes unsupported, pulls down the ivory lever, raising the hook of
the pin, which, releasing the spring, sets the bell ringing.
The periodical journals a few years ago abounded with plans of simple alarums;
and any person having a taste for such trifles in mechanics might easily multiply
them, as the materials as well as the arrangements of parts may be almost in-
finitely varied. Sand, passing through a minute perforation, (as in the hour-glass,)
and charging a receptacle, whose weight in due time gave motion to a bell, was
a common expedient. The substances used for domestic light have also been
called into use, to show by their uniform decrease of quantity the time passed,
and by their decrease of weight in consequence allow the reaction of a constant
force to give motion to an alarum. The most perfect and elegant piece of
mechanism for this purpose, is Berrollas's patent watch alarum, which we have
fully described under the head HoRology.
ALBUMEN. A viscous ropy fluid, found in its greatest purity in white of
eggs, from whence it derives its name. The serum or colourless part of the
blood, the crystalline humours of the eye, and all animal matters, contain it in
great abundance. It is also found in many vegetables, more particularly in
those which undergo spontaneous fermentation. The juice of the papau tree,
mushrooms, and many other fungi, contain considerable quantities. Pure
albumen may be obtained by agitating the white of an egg with alcohol, which
separates the aqueous particles. From the liquid thus obtained, it does not,
however, appear that more than 15% per cent. of dry albumen exists; for if it
be exposed to a low gradual heat, it will lose about 80 per cent. of water, and
44 of a liquid uncoagulable matter. According to the best analysis, it is
composed of
Carbon . . . . . . . . . . 52.883
sº Oxygen . . . . . . . . . 23.872
Hydrogen . . . . . . . . . 7.540
Nitrogen . . . . . . . . . 15.705
100.
The most remarkable property of albumen is that of its coagulating or forming
a white solid substance, by the application of gentle heat. At the temperature of
1600 Fahr. it solidifies, and is then insoluble in water. On this account, its existence
in water may be easily detected. According to Dr. Bostock, if water contain
mir of its weight of albumen, it becomes opaque on boiling, by the coagulation
of this substance. It may also be coagulated by a powerful voltaic battery. If,
after coagulation, a continued heat be applied, a semi-transparent horny sub-
stance is formed. Albumen is soluble in water by agitation, but the coagulum
is not, unless artificial pressure be applied; this may, however, be dissolved by
most of the acids. It is generally supposed that a minute quantity of sulphur
exists in albumen. If the serum of blood is evaporated in a silver vessel, a coat
of sulphuret of silver is formed: this also occurs when a spoon has been dipped
frequently in a boiled egg, Albumen is a delicate and valuable test for that
fatal poison, corrosive sublimate, which it precipitates from its solution in white
flocculi. It also renders the poison inert, and is therefore employed as a remedy,
A valuable cement for joining earthenware, china, stone, &c. is made by mixing
albumen diluted with water and quick lime. This cement will harden under
water, and sets in the open air almost immediately. Albumen is very extensively
employed in clarifying wines, and also in rendering leather supple. It undergoes
decomposition rapidly if exposed to the atmosphere, and emits a very nauseous
odour. The coagulated albumen is not liable to decomposition.
ALCOHOL. 57
ALCHEMY. The word is derived from the Arabic al (the) and kemia
(excellent), and signifies the most exalted science. . It is a branch of chemistry,
the objects of which were the transmutation of inferior metals to gold; the
discovery of an elixir vitae, or universal medicine; an universal solvent; and
other visionary and impracticable schemes. The Saracens are supposed to have
first introduced the art into Europe; and so eagerly was it pursued by many
of the most exalted in station and even in knowledge, that monarchs have not
been ashamed to practise it, or to be duped by it. It is said that the Emperor
Caligula endeavoured to obtain gold from the sulphuret of arsenic; and Edward I.
witnessed an attempt made by Raymond Lully to obtain the precious metal
from iron, which it was believed he accomplished. Most of the alchemists
imagined that gold was the only elementary metal, and that the others were
merely gold contaminated by foreign matters, from which it was possible to
separate it. It was also imagined that mercury might be solidified, and that
silver would be the result. In these futile pursuits many lives were spent, and
splendid fortunes sacrificed. The art of the professors of alchemy was shrouded
in mystery, which none but the initiated could penetrate. Their language was
symbolical, and they either believed or propagated the notion that supernatural
influence was necessary, and might be commanded in their pursuits. The student
was sometimes required to qualify himself for the attainment of his object by
acts of devotion and charity. The operations were by some only attempted when
planetary influence was supposed favourable to success. So many exalted per-
sons became the dupes and victims of the professors of alchemy, that in the reign of
Henry IV. an act was passed prohibiting all attempts to make gold or silver under
the pain of felony. From the numerous well-authenticated instances of persons
having procured gold by certain mystical operations with the aid of fire, it is
generally believed that a fraudulent slight of hand was practised. A hollow
rod, containing gold dust, is said to have been employed in stirring the contents
of the crucible, or the precipitated solution of gold used as a component in the
powder of projection. In these ridiculous attempts, however, many valuable
chemical discoveries were accidentally made. Porcelain china was first obtained
by an alchemist in search of the philosopher's stone.
ALCOHOL. The purely spirituous part of liquors, which have undergone
the vinous fermentation. It is the product of the saccharine principle formed
by the successive processes of vinous fermentation and distillation; and all fer-
mented liquors will afford it. Although brandy, rum, arrack, malt spirits, and
the like, differ much in colour, taste, smell, and other properties, the spirituous
part, or alcohol, is the same in each. The chief properties of alcohol are the
following: It is a colourless transparent liquor, very movable and light, from
which cause the bubbles formed by shaking it subside instantly. Its smell is
poignant and agreeable, and its taste hot and pungent. It is so exceedingly
volatile as to be converted into vapour by the heat of the hand; when exposed
to the air, it evaporates at 100 above the freezing point, and leaves no residue
except a little water, when not quite pure. It boils at about 1650 Fahr., and it is
generally supposed that it cannot be frozen, although Dr. Hutton asserts that he
succeeded in freezing it; but as he kept his method a secret, no one has been
able to repeat the process. Alcohol, when heated in contact with air, if it
be pure, burns with a light flame, without leaving any residue, and yielding by
the combustion a vapour, which is found to be nothing but water, and the weight
of which Lavoisier found to exceed by ; part the weight of the alcohol consumed.
Alcohol mixes with water in any proportion, giving out heat by the mixture;
and a mutual penetration of the parts takes place, so that the bulk of the two
liquors, when mixed, is less than when separate. So strong is the affinity
between these two fluids, that water is capable of separating alcohol from many
of the substances which may be united with it; and again alcohol decomposes most
saline solutions, and precipitates the salts. The following substances are soluble
in alcohol in different proportions: all the alkalies, when pure; several of the
neutral earths and metallic salts; sulphur in vapour; phosphorus slightly; the
essential oils; and the odorous part of vegetables, resins, and gum-resins, wax,
spermaceti, biliary calculi, &c. The following substances are insoluble in alcohol:

58 ALCOHOL.
the alkaline (arbonates; all the sulphates; some of the nitrates and muriates;
metals; metallic oxides and metallic acids; all the pure earths; the fixed oils,
unless when united to alkalies, or converted into drying oils by metallic oxides;
muscular fibre; the coagulum of blood; and albumen. To ascertain the purity
of alcohol, various methods have been devised. It has been thought that alcohol
which burns readily and leaves no residue is very pure, but this test is fallacious,
for the heat produced is sufficient to dry up part of the water. Another method
is, to drop a small quantity of it on gunpowder, and set fire to the spirit, and if
the spirit be pure, it will burn quietly on the powder, and the last portion of it
will ignite the powder, but if the spirit be watery, the powder will not explode.
This proof is, also, not to be depended upon ; for if any considerable quantity
of even the best alcohol be poured on a small quantity of powder, the water
which it affords as it burns, moistens the powder and prevents it from kindling;
and if it be only barely moistened, any spirit that will burn will inflame it.
The most accurate method is to find its specific gravity by a hydrometer, noting
carefully at the same time its temperature. The uses of alcohol are very
numerous, and it is extensively employed in medicine and the arts. In com-
bination with copal, resin, &c. it forms varnishes. From its antiseptic power it
is well calculated to preserve anatomical preparations. Its gentle and steady
heat, unaccompanied by smoke, renders it eligible for burning in lamps; and
from the impossibility of freezing it in any known degree of cold, it is well
adapted for indicating the lower degrees of temperature in the thermometer.
Having thus briefly noticed the properties and uses of alcohol, we shall proceed
to describe the process by which it is obtained, giving, at the same time, an
account of several modifications of the apparatus employed, which have been
recently invented, and embracing a description of the most improved French
distilling apparatus. The substances from which alcohol is chiefly prepared,
are the juice of the grape, molasses, grain, and the farina of potatoes; these
substances containing a large portion of saccharine matter, which is the basis of
the vinous fermentation. The mode of extracting this saccharine matter depends
upon the nature of the substance operated upon; but a saccharine solution
being obtained, the mode of converting it into alcohol is the same for them all.
The solution is first set to ferment, a certain quantity of yeast or other fermenting
principle being in some cases added. During the fermentation particular
attention must be paid to the temperature; if it exceed 770 Fahr. the fermen-
tation will be too rapid; if below 600 Fahr. the fermentation will cease. The
mean between these points is considered as the most favourable, and the fer-
mentation must be continued until the liquor grows fine and pungent to the
taste, but not so long as to permit the acetous fermentation to commence.
When the fermentation is finished, the liquor, if it be the juice of the grape,
is termed wine; but if the produce of other substances, it is termed wash. The
wine or wash is put into a still (of which it should occupy about three-
fourths,) and distilled with a gentle fire, as long as any spirit comes over,
which is generally until about half the wash is consumed. The form of the
common still is too well known to need any particular description; it generally
consists of a large boiler, made of copper, and fixed in masonry over a fire-
place. The boiler has a head of a globular form, to which is soldered a neck,
which, forming a complete arch, curves downwards, and fits into what is called
the worm. The worm is a long tube, generally made of pewter, of a gradually
decreasing diameter, and is curled round into a spiral form; it is enclosed in a
tub which is kept filled with cold water during the distillation. The produce of
the first distillation forms what is termed low wines; consisting of alcohol com-
bined with a large portion of water, on an average about one part of alcohol to
five parts of water. This is re-distilled, and affords proof spirit, consisting of
equal portions of spirit and water. The proof spirit being returned to the still
and re-distilled, the product is called spirits of wine or alcohol, being alcohol
combined with a very small portion of water, from which it is impossible to
free it by distillation, but which may be wholly or in great part removed by other
processes, to be hereafter described. The first important improvement in the
process of obtaining alcohol was introduced by a French chemist named Adam,
ALCOHOL. 59
who, by a happy application of scientific principles, was enabled to dispense with
the tedious re-distillations, and to obtain alcohol highly concentrated by a single
operation; economising time, labour, fuel, and (what in many situations is
highly important,) water for condensation; besides obtaining spirits of a superior
quality, with an increase in the quantity produced. The principle of his in-
vention consists in causing the vapour of the wine, with which the still is
charged, to pass through a quantity of wine contained in a vessel placed between
the still and the refrigerator, by which the vapour is condensed, and imparts its
heat and alcohol to the wine, until at length it enters into ebullition; and as
this wine, besides its natural portion of alcohol, has received the alcohol con-
tained in the vapour of the wine in the still, its vapour will be more highly
charged with alcohol than the former, and this vapour in its turn is condensed
in another vessel similar to the former, and so on through a number of vessels
in succession, until it arrives at the refrigerator highly concentrated. His
apparatus in its arrangement resembled “Wolfe's apparatus:” between the still
and the refrigerator were placed three or four strong copper vessels, named
eggs, from their shape. From the head of the still a pipe proceeded to nearly
the bottom of the first egg, and from the top of each egg, a similar pipe pro-
ceeded to nearly the bottom of the next egg in succession, the pipe from the top
of the last egg being connected to the worm, which first traversed a vessel or
reservoir containing wine, and then passed through a vessel containing cold
water. From the wine reservoir a pipe went to the still, communicating also
with the bottom of the eggs, by means of cocks, for the purpose of charging the
still and eggs with the liquid for distillation, the several vessels being each filled
about three-fourths. When ebullition takes place in the still, the vapour issuing
from it is condensed by the wine in the first egg gradually raising its tem-
perature until it likewise boils, and its vapour (which is richer in alcohol than
the vapour from the still) is in like manner condensed in the wine of the second
egg, and so on through the remaining eggs, the vapour issuing from the last
into the refrigerator being highly concentrated. The upper part of the refri-
gerator being immersed in the wine reservoir, the alcoholic vapour in its passage
through the refrigerator gives out a portion of its heat to the wine by which it
is surrounded, and is finally condensed by the cold water in which the lower
portion of the refrigerator is immersed. When the vapour from the still no
longer contains alcohol, the contents of the still are discharged, and the still is
re-charged from the first egg, which is charged in its turn from the second, and
so on throughout the series, the last egg being charged from the wine reservoir,
the wine in which has been already considerably heated by the passage of the
alcoholic vapour through the refrigerator. Although the principle of this in-
vention is admirable, and has served as the basis of a great part of the subsequent
improvements in distillatory apparatus, yet, as was to be expected, improvements
have been introduced in the construction and arrangement of the parts, several
of which we shall lay before our readers, for which reason we omit giving a
drawing of the original.
About the same time that Adam introduced the important improvement just
described, M. Solimani, Professor of Natural Philosophy in the Central School
of the Gironde, contrived to obtain the same results by a different method.
The principle upon which his invention is based is, that water to exist in the
state of vapour requires a temperature of 212° Fahr., whilst alcohol boils at
about 1659; and that if a mixture of the two vapours be exposed to any tem-
perature between these two points, a portion of the watery vapour will be
condensed, which will be greater in proportion as the temperature is below 2129.
The annexed figure represents Solimani's still, as improved by Curadau. a is
the door of the furnace; b the ash-pit; c the boiler, with a large cylindrical
head d, e the exit tube for the vapours, connected by a union joint to the worm
f in the tub g. This tub is filled with water, which is to be maintained at a
temperature depending upon the strength of the spirit required, and the spirituous
vapour that passes upwards through the worm f along the tube h, then descends
through the worm i i surrounded with wine, in the vessel k, where it becomes
condensed. The liquid spirit then runs through another worm l, surrounded by
60 ALCOHOL.
cold water, which completely cools it before it is discharged by the pipe n into
the recipient o. To prevent the water in the tub g from becoming too hot by
the passage of the heated vapours through the worm f. and to preserve it at an
even temperature, cold water from an elevated cistern is introduced at the
|
bottom by a pipe p, the quantity being regulated by a stop-cock; and the wine
which surrounds the worm i i in the tub k is supplied from a vessel above, by
means of the pipe q. This wine in the course of distillation grows hot : it is
therefore used to charge the still as often as the former charge is worked off,
and the spent wine drawn off by the cock t, and as it is economical to take off
the hottest portion, the cock q is opened, when the cold wine from the cistern
above enters at the bottom of k, and forces the upper or heated portion along
the pipe u into the boiler of the still. The spirituous vapours formed in the tub
k are conducted by the head r and the curved necks into the worm f where it
takes the course of the vapours which proceed from the still. The tub m is
kept as cold as possible by an ingenious contrivance of M. Curadau. A number
of spiral pipes surround the tub on the inside, the ends of only two of which
are shewn in the figure to avoid confusion. Now, as the upper part of the tub
is always the warmest, a current of air is produced in these pipes, which serves
to cool the water in which they are placed. The worm f being surrounded
with a medium of about 1800 Fahr. returns to the still the greater portion of
the watery part of the vapours, so that by this apparatus spirits of great strength
may be obtained at a single operation.
Berard's Improved Still. This invention consisted in the application of a lofty
neck and head to the body of a common still, which, being exposed to the
cooling influence of the air, a considerable condensation took place in those
parts, but the liquor thus re-formed was not permitted to run back immediately
into the boiler, but to fall upon partitions with raised ledges, so that the ascending
yapour had to traverse over the successive layers of fluid in the partitions, and
became for the most part condensed in its passage, only the strongest or purest
spirit passing beyond the head.
Instead of a more particular description of Berard's method, we shall proceed
to the notice of Mr. Derome's still, in which the method is introduced with
considerable improvements. This apparatus consists of seven vessels or parts,

ALCOHOL. 61
performing separate offices : namely, a boiler A.; a distilling column B C; a
rectificator C C ; a condenser I Q; a refrigerator p ; and a reservoir s ; in
which the supply from another vessel U is regulated. It is considered prefer-
able to have two coppers like that at A, set in the masonry close to each other
*
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so that the heated air from the burning fuel under one copper may be conducted
under the other. Two communications are also to be made between the two
coppers, the first by a pipe proceeding from the bottom of A to the upper part
of the other; the second by another pipe rising from the top of the latter, (not
represented) and descending through the top of A to the bottom of the vessel,
to carry all the vapour generated underneath the liquid therein. At a b is a
glass tube to show the exact height of the liquid in the copper. The interior of
the distillery column, B C where the separation of the alcohol takes place, is full
of shelves perforated with small holes, through which the vapour from A neces-
sarily passes as it ascends, and comes in contact with the wine or liquid to be
distilled, that passes through the same apertures; both the wine and the spirit
are thus retarded in their progress, and become intimately mixed. The small
tube c d is of glass, to show the state of the process going forward in the rec-
tificator C C, which is only an extension upwards of the column beneath,
containing similar perforated shelves, and provided with a glass tube e f to
show the state of the process in this part. The vapour rising to the top of the
rectificator passes out through the neck H into a long worm, coiled horizontally
in the condenser I Q, which is a copper cylinder. This vessel contains wine

I
, 62 ALCOHOL.
that becomes heated by passing through the worm. To collect the spirit that
becomes condensed in the worm, the lower side of each coil has an opening
into a short tube, of which there are as many as there are coils to the worm.
To these tubes there are cocks, to draw off, as may be required, the products of
any or all of them (the most distant from the rectificator being of course the
strongest spirit,) either into the refrigeratory, by the upper long inclined tube
represented, or by the lower one back again into the rectificator for a second
rectification. The condenser is divided into two chambers, by a partition o,
with a communication between them at the lower part; there are also three
manholes closed by lids M N O in the condenser, for the convenience of having
it cleaned; and it has a cock F to draw off its contents. The wine is constantly
supplied to the condenser by the pipe K L, and as constantly flows off by the
tube D E. p constitutes the refrigeratory or cooler, and is also a copper
cylinder containing a worm, that receives the condensed vapours through the
pipe l m, and delivers the cooled product through the opening V. The cooler
is constantly supplied with cold wine by the pipe R, which enters at the bottom
of the vessel, and the wine passes off at the top of the vessel by the pipe K L
into the condenser IQ. W is a cock, to empty the cooler; S is the reservoir
which contains the wine; it has a cock p, by the opening of which the quantity
of wine to be supplied to the apparatus is regulated; and in order that this
may be equal, the liquid is kept at a uniform height by means of a ball cock q T,
the pipe to which is connected with the principal reservoir, which, for example,
may be the vessel U.
Mode of conducting the operation. The cock p being opened, the wine from
U passes through all the vessels into the two coppers, to the desired height,
which is ascertained by the two glass gauges. The distilling column is charged
with as much wine as will prevent a free passage of the vapour; and when the
condenser and cooler are full, the entrance of more wine is stopped, and the
communication is not re-established by the cock p until the wine in the coppers
has parted with its alcohol, and the liquid in the condenser is hot enough to be
introduced into the distilling column. After this, a small stream, proportioned
to the size of the apparatus and the rapidity of the work, is kept constantly
running from S, and then begins what is termed the continued process, all the
previous work being only preparatory. After this, the supply of the vessels
with wine, the evaporation, condensation, and cooling, go on independently,
requiring only attention to the fire.
Winter's Patent Distilling Apparatus consists of two vessels of a peculiar
construction, which may be applied to stills of every form; and will enable the
distiller to extract the whole of the spirit contained in the wash at one operation,
instead of the repeated distillations necessary in the usual mode. These two
vessels contain condensers, which, as in Solimani's apparatus, are surrounded
by a fluid maintained at such temperatures, as to condense any desired portion
of the aqueous parts of the vapour from the still before it enters the refrigerator.
The apparatus is shown in the annexed Fig. 1. A is a tube by which the vapours
enter from the still into the first receiver B; C a conical surface or plate; D
the principal vapour tube, which being closed at the top, the vapours descend
by the small tubes G into the chamber F. These small tubes are placed all
around the principal tube, which are inserted in the holes shown in the engraving
just above D. The apparatus is surrounded with water heated to 1709, and is
contained in the tub or bath T, shown in section; and as the vapours contained
in the tubes are, by this arrangement, separated into small portions, a rapid
condensation of the aqueous parts takes place. A number of bent tubes, as at
H, are fixed in the annular plate, which covers the receiver at B with their
upper ends, a little above the surface, which serve to carry off the condensed
liquid back into the receiver B. The vapour improved in its spirituosity, is
then collected in the chamber F, and passes from thence by the tube I into the
second receiver K. The top plate of this receiver K, as well as the bottom
plate of the third receiver N, have a number of openings or apertures forming
concentric circles, as at L. L., Fig. 2, in the plan of the apparatus, which we also
annex. Into each of these annular apertures L L are fixed two copper cylinders,
ALCOHO I,. 63
one within the other, and only a quarter of an inch apart; and as there are
four such apertures, there are consequently eight cylinders, or four pairs in the
apparatus, which are exhibited in section in the annexed Fig. 1. at M. M. O O
Fig. 1.
are tubes which pass through the receiver at K, to convey water between the
cylinders; similar tubes are passed through the receiver N, by which means
the water is diffused over every part of the extended surface of the apparatus,
Fig. 2.
effecting thereby almost as rapid a condensation of the aqueous portion of the
vapour, as if the water were in actual contact with it. The vapours from the


64 ALCOHOL.
lower receiver K ascend, as before mentioned, through the narrow spaces
between the cylinders into the upper receiver N, in a high state of purity and
strength. From this last hold it proceeds into the worm by the tube P, where
it is instantly condensed by the refrigerating effect of the cold water, by which
this part of a distillatory apparatus is always surrounded. The water contained
in the second bath T, shewn in section, is heated to 1400 (or less, as the strength of
the spirit may require,) that being a temperature at which the vapour of water,
as well as that from the empyreumatic oils, cannot exist. This apparatus is stated
to be so effective, that in an experiment made at an eminent distillery in London,
in the presence of several experienced distillers, “feints 80 per cent, under proof
were put into the still, and came out at one operation at 55 per cent. over proof.”
Grimble's Patent Distilling Apparatus consists of a series of very small
tubes, fitted to the mouth of an ordinary still, the upper ends being received
-. | | ºil.
iſſi lift
|||||
|
|
| | ||
into a close box, from whence the uncondensed vapour passes on to the worm,
whilst the condensed portion is returned to the still. It is shewn in the accom-
panying engraving, where A is the still ; B the botton box of the apparatus,

ALCOHOL. 65
fitting on the still: , b, a plate of copper, fitting on the box B; c c c are open
iubes, through which the vapour ascends into the top box D, where the sepa-
ration of the aqueous vapour takes place from the spirits; the tubes c c c project
through the bottom plate of the box D, so that the oily and aqueous matters
are not allowed to return by the small tube, which would impede the vapour
issuing from the still, but run back into the still by the larger corner tubes d d,
which are on a level with the bottom plate at ele. The lower ends of these
tubes are turned up syphon-wise, to prevent the ascent of the vapour from the
still. c. c is a stay plate for the tubes; in the box B is a range of tubes g g g,
through which a current of cold water is maintained when the spirit is required
very strong, (but not generally used) having its egress and exit at f h. F is
the pipe that conveys the spirituous vapour into the worm, and a thermometer
at E serves to regulate the operations. We understand that an apparatus of
this description is or was in use at Messrs. Booth and Co.'s distillery, but do
not know how far it answered the proposed end.
Evans's Patent Distilling Apparatus. The object of this invention is to
effect a more equal and uniform distribution of heat to the liquid under dis-
tillation, than is obtained in stills as hitherto constructed, as well as obtaining
spirits of great strength at a single operation. As the plan is totally different
from any of the preceding ones, and as some of the arrangements evince great
ingenuity on the part of the inventor, we lay it before the reader, without,
however, expressing an opinion as to its applicability in practice. The engraving
represents the whole operation at one view. a is a pipe which conveys the
wash or fermented liquor into a reservoir b, where it is maintained at a certain
level by the ball valve c. d is the still, which is a revolving copper cylinder,
with ledges fixed in horizontal lines against the inner surface, to increase the
agitation of the wash as it turns upon its hollow axis fg; its motion is derived
from the spur-wheel h acting upon the pinion i fixed upon its hollow axis; j
is the rectifier; this is formed of a large pipe of uniform bore, coiled up into
the spiral figure exhibited, with the ends bent, so as to form axes for rotation,
on one of which a pinion k (corresponding to that at i) is fixed; and this
pinion is acted upon by another spur-wheel l on the same shaft as the other; m
is the common distiller's refrigeratory; and n a receiver for the distilled spirit.
The figure represented in dotted lines, is intended to show the position in
which the still is drawn up when it is necessary to cleanse it. For this purpose
there is at o a universal joint, of a peculiar construction, which enables it to be
easily done, after having separated the connecting tubes at the union joint,
represented' contiguous thereto. The rectifier j communicates with the still
through the hollow axle g, and with the refrigeratory through a stuffing-box;
and the still communicates with the reservoir by means of a syphon passing
through the hollow axis f. The outward part of the syphon has two unequal
limbs; the short one is inserted in the reservoir for the purpose of charging
the still with wash, and the long limb for discharging the spent liquor. In
order to charge the still, the ball of the valve is pressed downward, so as to
raise the liquid above the top of the syphon; this sets the syphon in action,
and causes it to fill the still to the same level as the liquid in the reservoir.
Thus prepared the fire is lighted, and a slow rotatory motion is given to the
still by hand or any other convenient first mover, applied to the shaft upon
which the spur-wheels h and l are fixed. The continuous motion of the liquid
prevents the formation of empyreuma, however fierce the fire may be; and by
the agitation of the liquid, and the intensity of the heat applied, a rapid pro-
duction of vapour is caused, which immediately enters the hollow axis g, and
passes into the coiled worm of the rectifier j. It is here necessary to observe,
that this capacious worm revolves in the direction pointed out by the arrow ;
consequently whatever portion of the vapour becomes condensed in it, runs out
at every revolution back through the hollow axis g into the still, and the hollow
axis g is for this purpose made tapering wider towards, the still, so as to give
the liquid a descent to run freely into it. The vessel j is, therefore, properly
termed a rectifier, as it separates the water from the diluted alcohol before
passing out of it into the refrigeratory in. In this it arrives in a state more or
66 ALCOHOL.
less concentrated, according to the temperature maintained in the rectifier,
which is regulated as usual by a thermometer. The spirit may consequently be
drawn at one operation at almost any desired strength. An interesting feature
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vapourized; and this operation is uniformly continue l during the rotation of
the vessel, owing to its passing through a tubular axis. The syphon in like
manner enables the still to be discharged without stopping the machinery.
When it is necessary to recharge the still with the fire under it, a thick cast-
iron sliding plate is drawn from the back, so as to interpose itself between the fire
and the still, and thus prevent any injurious effects to the contents of the latter.








































ALCOHOL. 67
The following engraving represents an apparatus which has been proposed
for distillation by means of steam or heated air, acting through the medium of an
extensive metallic surface upon a thin film of liquid, in order to promote a speedy
evaporation at a comparatively low temperature. a is a tall cylindrical vessel
containing the fermented wash to be distilled, which is supposed to be supplied
:* i
irº
--- i
E
regularly by a pipe from the brewhouse. By turning the cock in the pipe b,
the wash flows upon the exterior surface of the conical evaporator c, formed of
thin copper. The liquid is first received into a small basin, surrounding the cone
near its apex, having numerous small perforations at the bottom, by which
means the liquid is equally diffused in a thin stratum over the surface of the
cone c. d is the opening into the cone c, by which the heating medium is
admitted, and provided with a valve or cock for regulating the temperature;
and the heat being maintained at about 1800 but a small portion of aqueous
vapour would rise with the spirituous, and the spirit would thus be separated
at the commencement of the process from those matters which usually con-
taminate spirits of home manufacture. That portion of the wash that escapes

68 ALCOHO I,.
evaporation owing to the low heat, (and which would consist chiefly of water
and extractive matter,) will run off at the bottom of the cone by a circular
gutter, and from thence pass out by an aperture or pipe, as at e, while the
more spirituous rises between the inner cone c and the outer cone ff, enters
the neck g, and from thence proceeding through the spiral worm, shown in
he wash vat a, is received into the recipient h, partly in the form of vapour,
and partly in the liquid state; having in its passage through the worm com-
municated so large a portion of its heat to the wash in which the worm is
..mmersed, that a slight additional heat will be sufficient to separate its alcoholic
constituents. A small portion of strong spirituous vapour will collect in the
upper part of the vat a, which may be conducted off by the tube o into a separate
recipient or refrigeratory, as the spirits thus produced will be of superior purity.
The more volatile portion of the vapour passes onwards through the open tube
i into the great refrigeratory k. This is a large cylindrical vessel or vat, with a
strong false bottom at l, into which are soldered a great number of small thin
pipes t t rising vertically and open at both ends, the upper extremities being
soldered into the bottom plate of the chamber m. The portion of the vat above
the false bottom l is kept filled with cold water by a service-pipe inserted at the
lower part, the vapour, therefore, rising up through the pipes t t, is exposed
very much subdivided to a very extended metallic surface, surrounded by cold
water, by which its caloric will be very rapidly abstracted ; the condensed
liquid which then runs back down the pipes, meets with the rising vapour in
its progress, and, by that means, condenses a further portion at a higher tem-
perature than would have otherwise been accomplished, which is the object of
causing the vapour to proceed upwards instead of forcing it downwards, as in
the ordinary practice. By these arrangements it is expected that very little
vapour will reach the upper chamber m if the water is not allowed to get above
800; but if the supply of cold water should be insufficient for the purpose, the
vapour must proceed, of course, from the tube n to another refrigeratory. To a
bevelled wheel at q are attached two long bars, or scrapers r r, the edges of
which scrape or brush against the surface of the cone to clear it of sediment or
incrustrations, which will then fall to the bottom; the bars are connected by a
ring at s; such an apparatus will be useful in the distillation of liquids that
contain much extractive matter. From the above description it will be seen
that the distillation is carried on without intermission, the wash being admitted
in a small stream, in such quantity as to allow the alcoholic portion to be
evaporated in its passage over the heated surface of the cone c, and the remain-
ing portion to pass off in a stream by the waste pipe at e, as long as fermented
wash is supplied from the brewhouse. It has been stated, though we know not
upon what authority, that it has been found difficult to separate the alcoholic
from the aqueous parts of fermented liquors, by simply causing them to flow
over a heated surface; and that preference has therefore been given to stills
constructed upon the combined principles of Adam and Solimani.
We have already mentioned the pulp of potatoes as amongst the substances
from which alcohol may be obtained; and the manufacture has been for some time
past carried on in various places with great success. The apparatus and process
which we are now about to describe, are both of foreign invention, and were intro-
duced into this country by the patentee, M. Saintmarc, of the Belmont Distillery,
Vauxhall. The potatoes being first washed clean, are taken to a mill and ground
into pulp. This pulp is then mixed with a large quantity of water, which takes
up the chief part of the contaminating brown colouring matter, and it is then
poured through a coarse sieve, which, detaining those pieces that have escaped
the mill without being ground into pulp, they are rejected as ineligible for fer-
mentation, and applied to the feeding of pigs. . The pulpy liquid thus freed
from the coarser pieces, runs into a trough containing a number of small holes,
and lined in the inside with a linen cloth sufficiently fine to prevent the floating
Fºlº of starch from passing through; the water then drains through the
inen, leaving the pulp and starch to settle in a mass. When it has sufficientl
drained, and become solid and compact, it is removed from thence and laid
upon a plastered floor, which rapidly absorbs a great portion of its moisture.
A LCOHOL. tºg
To dry it entirely, it is afterwards placed in a kiln or stove, which completes
that part of the process. . In the dry state the pulp may be kept uninjured for
years, and may therefore be stored away for future use. The wet pulp being,
however, equally serviceable for immediate fermentation, there is no occasion to
dry it if the several processes in distillation can be carried forward at the time
|
Supposing the pulp to be used in the dry state, it is cut, or broken to pieces,
. mixed in the vat a, with sufficient hot water to bring it to the consistence
of cream. The vessel b, lined with lead, and called the decomposing vessel, is
then to be supplied with water to the depth of about six inches; to this, a quantity
of sulphuric acid is to be added, in the proportion of three pounds of acid
to every hundred pounds of dry pulp; but only ten pounds of the acid to
every hundred pounds of the wet pulp. The diluted pulp is then to be dis-
charged from the vessel a, through the cock into b, containing the diluted
acid; steam is then to be admitted from a boiler, (not shown in the engrav-
ing,) by turning the coek in the pipe e, which descends to the bottom of the
vessel, where it is made to issue from a steam-box; the heat causes the mix-
ture to boil, and, after four or five hours' ebullition, the decomposition is con-
sidered complete. Before, however, describing the next part of the process, we
should notice that a worm-tub d, supplied with water from a service-pipe, is
E. on the top of the decomposing vessel; the vapours from the boiling
iquid beneath enter this worm, and are therein condensed by transmitting
their caloric to the surrounding water; and the water thus made hot, serves
for replenishing the vat a with fresh portions from time to time, as it may be re-
quired, by means of a connecting tube ffurnished with a stop-cock. The contens
of the vessel b, after decomposition, are discharged into the saturating vessel 7,
and, during the time that it is running, a quantity of lime, or chalk, in solution,
may be poured in among it as long as any effervescence continues, which will
vary according to the degree of concentration of the acid; but, in general, three
pounds of chalk, or lime, will be found sufficient to saturate each pound of sul-
phuric acid employed in the preceding part of the process. The liquid in the
saturating vessel having now become transparent, it is to be drawn off into the
fermenting vat h, placed beneath, leaving the precipitated sediment undisturbed
K
|


7() ALCOHOL.
at the bottom while the clear liquor is running. The discharge cock being
closed, the sediment may be stirred up with a quantity of water, to take up
whatever saccharine or fermentable matter it may contain ; this should be
allowed to subside again, and the clear liquor then to be added to the former in
the vat beneath. #. promote the fermentation, a quantity of yeast is now to
be added to the liquid, in the proportion of three pounds to every hundred
pounds of potatoe pulp. During the fermentation, which usually occupies from
fifteen to twenty days, the temperature of the liquid should be preserved at
from 900 to 1000 Fahr., and the atmosphere of the room where it is conducted,
at from 800 to 859. The patentee having discovered that the introduction of
hydrogen gas facilitates the fermentative process, besides increasing and
improving the product, further directs that the vat should be furnished with a
tube i, along which the gas is to be forced, by means of a pump, into the
liquid. The tube, after descending to the bottom of the vessel, takes a hori-
zontal serpentine course; in this part it is perforated with numerous small
holes, through which the gas escapes and bubbles up through the liquid. This
injection of the gas should be continued until the carbonic acid gas, in the
upper part of the vat, contains an excess of the hydrogen. The patentee is of
opinion that the introduction of hydrogen gas may be very advantageously
used, not only in this process, but in the fermentation of all matters from
which spirit or alcohol is to be extracted. When the vinous fermentation has
ceased, the liquor is to be drawn off through the tube into the still k. This
still is of the ordinary construction, except that instead of having a large head,
or capital, it has a long neck rising perpendicularly from the body, the object
of which is, that the aqueous part of the vapours may be condensed before
entering the inclined part, and fall back into the still, while the more volatile
or spirituous pass on alone into the bent arm, and from thence into the refri-
gerator or worm-tub l, where it is converted into the ordinary first product of dis-
tillation, called low wines (which is a very weak spirit). The |. wines are
then taken to another called the low wine-still, a section of which is shewn in
the accompanying engraving.
==
==
-------
|-
l
m is the body of the still fixed in brick-work wer a furnace; a long perpen-
dicular neck proceeds from this as in the wash-still, the object of which is, that
the aqueous part of the vapour may be condensed as it ascends, and fall back
again into the still, while the more volatile and spirituous passes on through
the tube n to the bottom of the vessel 0. This last-mentioned vessel has a tub
of cold water placed on the top of it, which is kept supplied by the service-
pipe p, and as the tube n passes through this tub, the greater part of the vapour
at first condenses and is received into the vessel o in a liquid form ; but as the
vapour is continually coming over from the still, the condensed liquor is at
length made to boil: the vapour filling the upper part of the vessel, from thence
passes up the tube r into the long cylindrical vessels, which is partly immersed
in a long cistern constantly supplied with cold water by the usual means. The

A LCOHOL. 71
cylindrical vessels is divided by five vertical partitions into six compartments,
but having a communication from ene to the other by means of bent tubes pro-
ceeding from the upper part of the first compartment, to the lower part of the
second ; and, in the same manner, from the second to the third, the third to
the fourth, and so on. It will now be readily seen that the most aqueous part
of the vapour will be condensed in the first compartment, while the more vola
tile passes to the second, where another portion of the vapour assumes a liquid
form; the more volatile still will proceed to the third, and thence to the fourth,
fifth, and sixth, according as the spirit is more or less divested of aqueous particles,
all depending, of course, upon the degree of heat employed in the furnace for
raising the vapour in the still m, and upon the degree of coldness of the water
surrounding the condensing vessels. To ensure, however, the condensation of
all the vapour, a tube g proceeds from the upper part of the sixth compart-
ment, rises to a considerable height, then takes a horizontal course, and,
finally, descends into a spiral worm placed in a tub of cold water, where,
making a long circuitous passage, it is delivered from the bottom into a receiver
in so concentrated a form, as to be nearly in the state of pure alcohol. At
the bottom of the cylindrical vessel s, a separate short pipe, with a cock, pro-
ceeds from each compartment, leading into the long pipe u, which being also
furnished with a cock at either end, the spirit contained in any compartment
may be drawn off distinctly; the contents of any, or all of the pipes, may like-
wise be drawn off by the pipe u into the vessel o for redistillation; and the
vessel o may be discharged back into the still when desired, by the pipe v
having a cock for that purpose. Although this apparatus is well adapted for its
intended purpose, and is new in this country (where the vexatious nature of the
excise laws preclude, in a great measure, any improvements in the art of
distillation) we must observe that little invention has been displayed on the part
of the patentee, as almost every part of it is copied from apparatus long since
invented, and in use in France. For a further account of distillatory appa-
ratus, we refer our readers to the article D1st ILLATION, under which head will
be found a description of a great variety of stills and apparatus connected there-
with, which the length to which we have extended the present article prevents
our noticing in this place. !
When, by repeated distillation, the alcoholic mixture is brought to a certain
degree of concentration, the affinity of the alcohol for the water with which it
is still combined, aided by the great excess in the proportion of the alcohol to the
water, becomes so great, that no further separation of the constituent parts of
the mixture can be effected by distillation. Alcohol being much lighter than
water, its spec. grav. is used as a test of its purity. Fourcroy considered it as
rectified to the highest point when its spec. grav. was 829, that of water being
1000; and this is, perhaps, nearly as far as it can be carried by mere distil-
lation. Alcohol, however, is not in this state pure (nor, indeed, is any process
known by which it may be rendered anhydrous, or perfectly free from water);
but it may be freed from a further portion of water by means of an alkaline
salt. For this purpose, muriate of soda (common salt), may be advantageously
employed, by first depriving it of its water of crystallization by heat, and
adding it hot to the spirit. It is, however, considered preferable to employ the
sub-carbonate of potash. About a third part of the weight of the alcohol
should be added to it in a glass vessel, be well shaken, and then allowed to
subside. The salt will be found to have absorbed water from the alcohol,
which being decanted, more of the salt is to be added, and the process con-
tinued until the salt falls dry at the bottom of the vessel. The alcohol must
now be subjected to final distillation in a water-bath, to deprive it of the red
tint derived from the potash, as well as to free it from the alkali held in solu-
tion. A most important improvement upon this method of rectification has
been invented by a French chemist. It consists in placing a quantity of dry
muriate of lime, or other deliquescent salt, in a large shallow-covered vessel;
in this is placed another vessel of smaller dimensions, and resting upon the
bottom on short legs, and containing the diluted spirit (brandy for instance) to
be concentrated; the outer, or larger vessel, is then covered down, and properly
luted, to prevent the escape of the spirit. A series of double vessels are
arranged beneath the former, charged with the deliquescent salt only; and
pipes of communication lead from one to the other, and are furnished with
stop cocks. These arrangements, as well as the process, will be perfectly well
understood upon reference to the annexed diagram. a is the vessel containing
the deliquescent salt; b, that containing the
dilute spirit; the cover of a being well closed and a h wº /
luted, it is left for several days to attract the r
water from the spirit; and when the former is |
supposed to be fully saturated with , aqueous | d \. / |
particles, the spirit in b (considerably improved T I
in strength) is drawn off into d by turning the |
cock c. This second vessel being also provided
with a stratum of muriate of lime, the process of |e \
concentration recommences by a farther abstrac- H.
tion of the water contained in the spirit. In like
manner the spirit may be successively operated If \º- w +/
upon by the salts contained in the vessels e and
f, and, if required, by an additional number of vessels, until alcohol of the
greatest purity is obtained. As each vessel is successively emptied, the satu-
rated salt is taken away and replaced with a fresh quantity of dry salt, when
it is ready to operate upon another portion of spirit let on from above. There
is another method by which the strongest alcohol may be obtained, although
the process, as usually conducted, is rather dilatory. It has been ascertained
that bladder is impervious to alcohol, although pervious to water; so that if a
portion of alcohol be confined in a bladder, the water will be evaporated in the
course of a few days, whilst the alcohol remains, but in a highly concentrated
state. The following information on the subject is extracted from Ferrusac's
Bulletin, Mai, 1828, and, we doubt not, may be turned to practical advantage.
M. Soemmering, in a memoir to the Academy of Sciences at Munich, states
that alcohol in a vessel covered with a bladder, the latter not being in contact
with the fluid, loses, when exposed to a dry atmosphere, much of its water, and
becomes stronger; but if the vessel thus closed be exposed to a damp air, the
alcohol attracts humidity and becomes weaker. In a second memoir the author
states more particularly the effect of bringing alcohol into more immediate con-
tact with the membrane. If a bladder be filled with 16 oz. of alcohol at 750,
and be well closed and suspended over a sand bath, or placed near a warm
stove, so as to remain at the distance of more than an inch from the hot surface,
it becomes in a few days reduced to a fourth of its volume, and is nearly or
quite anhydrous. M. Soemmering prepares for this purpose calves' or beeves'
bladders, by steeping them first in water, washing, inflating, and cleansing
them from grease and other extraneous matters, tying the ureters carefully, and
then returning them to the water to clear off more fully the interior mucosity.
After having inflated and dried the bladders, M. Soemmering covers them with
a solution of icthyocolla, one coating internally and two externally. The
bladders thus become firmer, and the concentration succeeds better. It is better
not to fill the bladder entirely, but to leave a small space empty. The bladder
is not moist to the touch, and gives out no odour of alcohol. If the latter be
below 169 Baumé, the bladder then softens a little, and appears moist to the
touch. Bladders prepared as above may be employed more than a hundred
times, although they at length acquire a yellowish brown colour, and become a
little wrinkled and leathery. The swimming bladder of the salmon is not fit
for these experiments. Alcohol of 729 was put into one of them, and after an
exposure of thirty-two hours, it had lost more than one-third of its volume, and
was weakened 129: the alcoholic vapour was perceived by the smell. Of two
bladders of equal size, into one was put 8 oz. of water, and into the other 8 oz.
of alcohol. They were placed side by side exposed to a slight heat. In four
days the water had entirely disappeared, whilst the alcohol had scarcely lost an
ounce of its weight. Mineral waters, and the water of wells, evaporate and
deposit on the interior of bladders the saline particles which they contain.

A ſ, COHOL. 73
the heat be conveniently managed, absolute alcohol may be obtained in from
six to twelve hours. Solar heat is even sufficient to procure anhydrous alcohol.
Wine placed in prepared bladders contracts no bad odour; it assumes a deeper
colour, acquires more aroma and a milder taste, and becomes generally stronger.
Spirits of turpentine of 75° contained in a glass vessel closed with a bladder,
lost nothing in four years. Concentrated vinegar lost the half of its volume in
four months; the other half acquired more consistency, and had no longer an
acid taste. The water of orange flowers was about one-third evaporated in a
few months, appeared to have a stronger odour, and, consequently, had lost
nothing of its volatile principle. These experiments of M. Soemmering clearly
establishing the fact that bladder is impervious to alcohol, we have no doubt
that on account of the little heat necessary to effect this rectification, it may
be one of great economy, if an apparatus can be devised for conducting
the process extensively and with little labour. For this purpose we would
suggest that, instead of the ordinary animal bladder, the oesophagus of oxen
should be employed, as exposing a larger surface to the air, and as more con-
venient for fixing into a suitable framing, which might be placed in a heated
apartment, or, in warm climates, to the heat of the sun. Such an arrangement
is shewn in the following diagram. a a are the oesophagus bladders, distended
&
g---
ſ
|
º
between a framing b b and c c, which is exhibited as broken away towards the
middle, to show that it may be made of any convenient length or width. The
bars d d connect the upper and lower pieces, and carry the pivots or axles
which turn in the cross beams or supports e e, shewn in section. The upper
side of the frame b b represents a square or round tube, in which are made cir-
cular apertures for the reception of the upper ends of the bladders a a, kept
open and distended by wooden rings, and properly secured by cement. The
lower ends of the bladders pass º similar apertures in the bottom rail,
where they are cemented and kept closed up and secured from injury by a
board screwed over them into the rail c. c. . We will now suppose that fifty (or
any other number) of such bladders are fixed to a frame, and charged with
diluted spirit, by means of a hose and nozzle connected to the cock fj that
done, the cock f is to be closed. In the same manner let all the other frames
in the apartment or manufactory be charged, of which there may be any number.
In 100 frames 2000 or 3000 gallons might be suspended. The whole should
then be submitted to a moderate heat, as of the sun, or a stove, &c. When it
is found that the spirit has parted with its aqueous fluid in any of the frames,
they are to be turned half way round on their pivots, by which the upper side

74 ALCOHOL.
bb becomes the under, and the cock being opened, the concentrated spirit may
be discharged by means of a hose into suitable recipients. Instead of a movable
or swinging frame, a fixed one might be used, by forming the bottom rail (into
which the lower ends of the bladders are inserted) of a tube similar to the
upper one, and fitting it with a discharge cock. ©
From the circumstance of alcohol boiling at a temperature considerably
below the boiling point of water, many persons have supposed that its vapour
might be advantageously substituted for steam as a prime mover of machinery.
The first suggestion to this effect we think originated with the Rev. E. Cart
wright; but we are not aware of any attempts to carry it into effect previous
to those of Mr. Howard, who took out a patent in 1825, for an apparatus for
the purpose, and endeavoured with great perseverance to bring it to perfection,
but, we believe, without success, as we cannot find that any engines of this
description have been brought into use. The following description, with the
annexed engravings, will explain the nature of the apparatus. A and B are
Fig. 1.
y
* -º
º:
|
f
===E
---
==== -
==
s
|
Sº Sf
two cylinders of equal capacity, communicating at the lower part by a pipe, or
passage C. These cylinders contain a quantity of oil, mercury, or other fluid,
(which will not rise in vapour at the temperature to which it is to be exposed,)
sufficient to fill the base of one cylinder, and nearly the whole of the other
cylinder. Within the cylinder B is a piston exposed above to the pressure of
the atmosphere; it has a piston rod, and is packed in the usual manner. In
the other cylinder A is a thin metallic dish D floating freely upon the surface
of the oil, or other fluid, before-mentioned. This latter cylinder has a top, per-
fectly air-tight, fastened down upon it, and through a stuffing-box in the
centre of the top, passes a tube E terminating within the cylinder in a small
nozzle, pierced with numerous small holes. In the cover of the cylinder is a
flap-valve G, which is opened by a rod H striking it; the valve is kept up to
its seat by a crane neck-spring above it; the valve-rod works through an air-


ALCOHOL 75
tight stuffing-box I; a safety-valye K is placed on the top of the cylinder. In
the pisten is an orifice fitted with a plug, by means of which the height of the
fluid above the piston (it should always be kept a little above the piston) may
be regulated; and at N is a cock, by which the fluid may be withdrawn from
the cylinders. The cylinders, and the fluid contained therein, are heated by a
sufficient number of argand lamps placed beneath them; and the cylinder A,
and the lower part of the cylinder B, are surrounded by a easing, leaving a
small space between them, so as to confine and carry the heated air entirely
around them. On the top of the casing is a chimney P provided with a
register Q, the better to regulate the heat of the air within the casing. By
means of a small force-pump R, which is worked by the engine, a small quan-
tity of alcohol is drawn from the condenser, and thrown suddenly through the
pipe E on to the floating-dish D, which, being previously heated by the oil, or
other fluid medium, on which it floats quickly, converts the alcohol into vapour,
which, pressing upon the dish, and the oil on which it floats, forces the oil
through the horizontal passage, and raises the piston to its highest point of
elevation. The valve in the cylinder A being now opened, the vapour escapes
by a tube S into a separate vessel, and is there condensed; the piston then
descends by the pressure of the atmosphere, and the dish D is carried again to
the top of the vapour cylinder A. The tube S is divided in the middle by a
flat ring a of wood, cork, or other non-conducting substance, making an air-
tight joint, and is inserted into a circular tube, or hollow ring V V, from which
a number of small thin copper pipes U U descend. The lower ends of these
pipes are inserted into another vessel W, which forms a reservoir for the
vapour when condensed. The liquid formed by the condensation of the
vapour, may be drawn off by the pipe and cock d. The outer and upper part
of the condenser, has upon it a circular open basin X, which is º supplied
with water by a pump, or any convenient means. The small tubes U are each
wrapt round with flannel, or other porous sub- Fig. 2.
stance of like nature, the upper end of which
hangs over the bason X into the water; and,
acting like a syphon, conducts the water over
the surface of the tubes U, down into a vessel
Y below them. Within the circle, formed by
the small tubes, is a fanner kept in rapid motion
by the engine, by which means a stream of air
is thrown upon the wet flannel, and the heat is,
consequently, more rapidly extracted from the
condenser. Previously to setting the engine to
work, it is necessary to withdraw the air from
the vapour cylinder and condenser, which is
done by means of an exhausting pump or sy-
ringe, applied at c, to a pipe with a stop-cock
b fitted on the top of the condenser. The liquid
to be converted into vapour for working the
engine, is introduced into the reservoir at the
bottom of the condenser, through a tube e
closed by a screw cap f Fig. 2, shows a method
of affecting the condensation by injection. The
pipe s conveys the vapour from the vapour
cylinder into the condenserg, which is formed
of copper as thin as the pressure will admit of,
and which contains a portion of alcohol, which º
may be introduced by the tube e as before, or | t-
by a funnel o and a stop-cock p on the top of dº
g. A lifting pump h is put in motion by the r
engine, at the same time that the valve G (in
Fig. 1) is opened, and the pump withdrawing a quantity of the alcohol from
the lower part of the condenser g, injects it into the same vessel at the top,
after passing it through a pipe or worm i, the end of which k being pierced with
#
||
ſ




76 ALKANET.
many small holes, the liquid is dispersed throughout the vesselg, and condensing
the vapour therein, falls with it to the bottom. Part of this liquid is again thrown
into the vapour cylinder by the pump R, to be converted into vapour, as before
described; and part of it is again employed to condense the vapour, as last
mentioned. The condenserg and the tubes connected therewith, are placed in
a cistern which is kept constantly full of cold water. The engine above described.
acts against the pressure of the atmosphere, which also effects the return stroke of
the piston. The following diagram presents an - ſal
outline of an arrangement for avoiding this,
and producing a double action. a a are the
vapour vessels; b is the piston cylinder; c the
piston working horizontally. The arrangement
of the lamps, injecting tubes, &c. is upon the
same principle as before. The vapour is
alternately generated with the two vessels a a,
and withdrawn from them, and acts upon the
piston through the medium of the oil or other
fluid, upon which, or upon the thin copper
floats d d, the small quantity of fluid to be evaporated is injected, as before
described. The patentee states that aether or essential oils might be substituted
for alcohol, although he considers the latter preferable upon the whole, as it is
more readily and effectually condensed. We have seen an alcoholic engine,
intended for a 24-horse power, in occasional operation at the Iron Works at
Rotherhithe, where the patentee perseveringly continues his experimental efforts
on the great scale.
ALE. The name given to a species of malt liquor. See BEER.
ALEMBIC. The name formerly given to a common distillatory apparatus,
now termed a still. See ALcohol, and DISTILLATION.
ALKALI. The term is derived from an Arabic word kali, the name of a
plant containing an alkali. The alkalies possess these general properties in
their pure state. They are caustic and acrid to the taste. They dissolve animal
matter, and form a saponaceous compound with oils or fat. They combine with
acids in definite proportions; the respective properties of each are destroyed,
and a neutral salt is the result. On this account, they precipitate most metals
from their acid solutions. They change most of the vegetable blues to green,
and restore the colour of a vegetable blue reddened by an acid. They combine
with water in any proportion. The most important of the alkalies in commerce
and in the arts, are potash, soda, and ammonia. The two former of these are
generally called the fixed alkalies, and the latter, the volatile. Some of the
earths possess powerful alkaline properties, and have, therefore, by some writers
in chemistry, been classed with the alkalies: these are lime, magnesia, barytes,
and strontites. Many vegetables also contain matter decidedly alkaline; such
as morphia, hyosciama, strychnia, &c. The properties and uses of these
bodies, will be found under their respective heads.
ALKALIMETER. An instrument for ascertaining the strength of alkalies.
The best, perhaps, is a tube graduated into a number of equal parts. Acid of
a known specific gravity, diluted with water, and coloured with infusion of
litmus, is poured in until a given number of parts is occupied. The alkali
to be tried is accurately weighed, and gradually added to the dilute acid, until
the original blue of the litmus, reddened by the acid, is restored. The relative
quantity of an alkali requisite to neutralize a given portion of acid of uniform
strength, is a test of its strength.
ALKANET, or Bugloss. A genus of the Monogynia order, belonging to
the Pentandria class of plants. It is found chiefly in the warmer regions of the
continent; that which grows in England is inferior in the colouring power of
its roots, for which the plant is chiefly valuable. The greatest quantity is raised
in France, from whence it is principally obtained. If the root of this plant is
digested in oil, alcohol, or unctuous matter, a deep red colour is extracted,
which is extensively employed in colouring various unguents, and also in
staining mahogany and marble. The colouring matter exists in the bark of
º
º
º:
-E
--~~mº
E
sº-
tº-
E.

ALLOY. 77
the plant; and as the roots contain most bark, a greater quantity of colouring
matter is exiracted from theiſ thai from the other paris. -
ALLOY. A combination of two or more metals. The term is sometimes
employed to denote the inferior metal combined with gold or silver. Thus it
is said the standard gold of jewellers is 18 carats of gold and 6 of alloy, what-
ever metal the alloy may be. When metals are combined either by fusion or
cementation, the alloy formed generally possesses properties and characters
very different from those of the respective components. The density is some-
times greater, sometimes less; the fusing point in some cases is considerably
lower than the mean. Plasticity is sometimes communicated, sometimes de-
stroyed ; and the malleability and ductility of the alloy seldom correspond
with those of the metals forming it. These important changes would lead to
the inference, that alloys are chemical combinations, and not mechanical mix-
tures; but there are many objections to this supposition, the most important
of which are, that metals may be combined in any proportions, and that they
may be separated by the process called eliquation, if there is a great difference
in the respective temperature of their fusing points. Thus, silver and lead may
be separated from copper by heat, the copper requiring a higher temperature
for its fusion than the other two metals combined; and an alloy containing a
volatile metal, as mercury, or zinc, may be decomposed by a strong heat, the
fixed metal remaining when the more volatile is expelled. In many cases, a
very small proportion of one metal is sufficient to change the most important
characters of another. A quarter of a grain of lead will render an ounce of
gold perfectly brittle, although neither gold nor lead are brittle metals. If a
crucible containing arsenic be placed in the same fire with a crucible containing
gold, the fumes of the arsenic will render the gold brittle. Some of the changes
thus produced are of the utmost importance in the arts, as many of the alloys
are far more valuable on account of the newly-acquired properties, than any of
the simple metals. Gold and silver, in their pure state, would be totally unfit
for the useful purposes to which they are applied, if they were unalloyed, on
account of their softness. Even the standard current coin of the realm is
alloyed, to render it hard, otherwise the impression would be speedily effaced, and
the coin, by abrasion, would soon become deficient in weight. Pure copper
would be unfit for many of the purposes to which it is so extensively applied in
the arts, if it were not alloyed by some metal to give it hardness; and it is sin-
gular that the metals employed for this purpose are all soft metals. Brass,
bell-metal, gun-metal, &c. are all alloys of copper with soft metals. Some
metals which will not combine together immediately, may be united by the
intervention of a third. Thus, mercury will not combine directly with iron;
but if zinc or tin is first added to the iron, an amalgam may be formed of it
with mercury. It may here be observed, that when mercury is united to any
other metal, the compound is called an amalgam. In order to make a perfect
alloy, a very intimate admixture, by mechanical agitation, should be effected
while the metals are in the fluid state. They should, therefore, be either con-
stantly stirred with an infusible rod, or repeatedly poured from one hot crucible
to another. Mr. Hatchett found that the lower end of a bar of standard gold
was of inferior specific gravity and value to the upper extremity, which would
be formed by the last portions of the metal in the crucible. The surface of
metals, also, should be carefully defended, while in the fluid state, from the
action of the atmosphere, by a stratum of wax, pitch, or resin, if the fusing
point be low; or by a layer of salt, pounded glass, borax, &c, if it be high. In
this article we shall merely give a brief account of the nature and composition
of the most important alloys, and their respective uses. Where the mode of
manufacture is complicated, and requires peculiar processes, we shall more fully
describe them under their several heads.
Brass is composed of variable proportions of zinc and copper, according to the
use for which it is required. In general, about 9 parts of zinc are added to 16 of cop-
per when melted. The best brass is not made by the direct combination of the two
fluid metals, but by the process called cementation (See CEMENTAtion). The
vapour of the zinc ore by this mode combines more intimately with the copper.
I,
78 ALLoys.
Manheim Gold—Three parts copper, 1 part zinc, and a small quantity of tin
If these metals are pure, and are melted in a covered crucible containing char-
coal, the alloy bears so close a resemblance to gold as to deceive very skilful
persons.
Tombac, or White Copper, is formed of variable proportions of copper,
arsenic, and tin.
Pinchbeck–Five oz. pure copper, and 1 oz. zinc. The copper must be first
melted before the zinc is added.
Prince's Metal is made of from 2 to 3 parts of copper, and 1 of zinc.; or of
common brass, with an extra portion of zinc.
Bell Metal—Six to 10 parts copper, and 2 parts zinc. For small bells, a
little zinc is added, and sometimes silver.
Tutania, or Britannia Metal.—Four oz. plate brass, and 4 oz. tin; when fused,
add 4 oz. bismuth, and 4 oz. antimony. This composition is added at discretion
to melted tin.
German Tutania.-Two drms. copper, 1 oz. antimony, and 12 oz. tin.
Spanish Tutania.-Eight oz. scrap iron, or steel, 1 lb. antimony, and 3 oz.
nitre. The iron or steel must be heated to whiteness, and the antimony and
nitre added in small portions. Two oz. of this compound are sufficient to
harden 1 lb. of tin. -
Queen's Metal.-Four and a half lbs. tin, 3 lb. bismuth, 3 lb. antimony, and
3 lb. iead. Or, 100 lbs. tin, 8 lbs. antimony, 1 lb. bismuth, and 4 lbs. copper.
This alloy is used for making tea-pots, and other vessels, which imitate silver.
Red Tombac.—Five and a half lbs. of copper, and 4 lb. zinc. The copper
must be fused in a crucible before the zinc is added. This alloy is of a red
colour, and possesses greater durability than copper.
White Metal.-Ten oz. lead, 6 oz. bismuth, and 4 drms. antimony. Or, 2 lbs.
antimony, 8 oz. brass, and 10 oz. tin. -
Gun Metal.—One hundred and twelve lbs. Bristol brass, 14 lbs. zinc, and
7 lbs. block tin. Or, 9 lbs. copper, and 1 lb. tin. Lead was formerly used in
this alloy to facilitate the casting, but at the battle of Prague it was found that
some of the pieces of ordnance formed of this metal were actually melted by
the frequency of firing.
Blanched Copper.—Eight oz. copper, and # oz. neutral arsenical salt, fused
together under a flux of calcined borax and pounded glass, to which charcoal
powder is added. .
Specula Metal—Seven lbs. copper, 3 lbs. zinc, and 4 lbs. tin. These metals
form an alloy of a light yellow colour, possessing much lustre.
Metal for Flute Key Valves.—Four oz. lead, and 2 oz. antimony.
Printing Types.—Ten lbs. lead, and 2 oz. antimony. The antimony is added
while the lead is in a state of fusion. The antimony gives hardness to the lead,
and prevents its contraction when cooling. Some manufacturers employ different
proportions of these metals, and some add copper or brass.
Small Type Metal.-Nine lbs. lead, 2 lbs. antimony, and 1 lb. bismuth. The
antimony and bismuth are added when the lead is melted. This alloy expands
in cooling; the mould is, therefore, entirely filled when the metal is cold, and no
blemish is found in the letters. Stereotype plates are formed of this alloy.
Some manufacturers employ tin instead of bismuth.
Common Pewter.--Seven lbs. tin, 1 lb. lead, 6 oz. copper, and 2 oz. zinc. The
copper must be first melted before the other metals are added.
Best Pewter.—One hundred parts tin, and 17 parts antimony.
Hard Pewter.—Twelve lbs. tin, 1 lb. antimony, and 4 oz. copper.
Common Solder —Two lbs. lead, and 1 lb. tin.
Soft Solder.—Two lbs. tin, and 1 lb. lead.
Solder for Steel Joints.-Nineteen dwt.s. fine silver, 1 dwt. copper, and 2 dwts.
D}^3.SS.
Silver Solder for Jewellers.-Nineteen dwts. fine silver, 1 dwt. copper, and
10 dwts brass.
Silver Solder for Plating.—Ten dwts. brass, and 1 oz. pure silver.
Gold Solder.—Twelve dwts. pure gold, 2 dwts. pure silver, and 4 dwts. copper.
ALLOYS. 79
Bronze.—Seven lbs. copper, 3 lbs. zinc, and 2 lbs. tin. The copper must be
tneſted before the OLIler IIlêUa IS are a ClüeCi.
Mock Platinum.—Eight oz. brass, and 5 oz. zinc.
Alloy of Platinum with Gold.—Fifteen parts pure gold, and 1 part platinum.
The gold must be melted before the platinum is added. This alloy is whiter
than gold. Platinum has the singular property of depriving gold of its peculiar
colour; if ten parts of gold are combined with only one of platinum, the alloy
will appear of the colour of platinum. There is another remarkable property
attending this alloy of gold and platinum, that it is soluble in nitric acid, which
does not act upon either of the metals in a separate state.
Ring Gold.—Six dwts. 12 grs. pure copper, 3 dwts. 16 grs. fine silver, and
1 oz. 5 dwts. pure gold. Jeweller's gold is made of variable proportions of pure
gold and copper, and sometimes of silver.
Imitation of Silver.—One lb. copper, and # oz. tin. This alloy will be of a
deeper colour than silver, but in other respects it is very similar.
Alloy of Platinum with Steel.–Platinum although the most infusible of
metals, when in contact with steel melts at a comparatively low temperature,
and combines with it in any proportion. This alloy does not rust or tarnish
by exposure to a moist atmosphere, for many months. The alloy is malleable,
and is well adapted for instruments which would be injured by slight oxidation,
as mirrors for dentists, &c. The best proportions do not yet appear to be known;
but it appears that if much platinum be used, the alloy has a damask or wavy
appearance. Steel for cutting instruments is much improved by even mºth of
platinum.
Alloy of Silver and Steel.—Steel 500 parts, and silver 1 part. If a large
proportion of silver is employed, the compound appears to be a mechanical
mixture only. The silver is distinctly seen in fibres mixed with the steel, and
the alloy is subject to voltaic action. When the proportion does not exceed
tº the compound appears to be a chemical union ; the steel is rendered much
harder, forges remarkably well, and is infinitely superior to the best cast steel
for cutting instruments, &c.
Alloy of Steel with Rhodium.—If from 1 to 2 per cent. of rhodium be com-
bined with steel, the alloy possesses great hardness, with sufficient tenacity to
prevent cracking, either in forging or hardening. This alloy requires to be
heated about 730 Fahr. above the best English cast steel in tempering. It is
superior to that metal; but the scarcity of rhodium will prevent the extensive
use of this valuable compound.
Fusible Alloys.-Four oz. bismuth, 24 oz. lead, and 13 oz. tin. Melt the lead
first, and then add the other metals. This alloy will melt in boiling water,
although the melting temperature of the several components is much higher;
viz. lead, 6120 ; bismuth, 4760; tin, 4420.
ALMOND. The well-known kernel of certain fruit trees, of which there
is great variety. Almonds contain a considerable quantity of oil, on which
account they are chiefly valuable. As an article of food, they possess little
nutritious matter, and if taken immoderately, are indigestible, and even poisonous,
on account of the prussic acid they contain. Bitter almonds yield a greater
quantity of this poison than the sweet; they are therefore poisonous to some
birds and small animals. Water distilled from almonds and other kernels, is
found to be destructive of human life. Noyeau and other cordials flavoured by
these substances, contain much of the bitter principle, or prussic acid. The
oil of almonds may be extracted by simple pressure; if they are heated, a
greater quantity is obtained. The oil from the bitter kernel is as tasteless as
that from the sweet; the bitter principle is soluble in, and may be extracted by,
water. Sweet almonds are extensively employed in medicine in the form of
emulsion. They are skinned, and triturated in a mortar with a small quantity
of water. After standing a short time, a thick cream separates, which will
render many resinous substances mixible in water. The almond emulsion is
generally combined with gum or sugar.
ALOES. The aloe is a plant of the Monogynia order, belonging to the
Hexandria class. The medical substance called aloes, is the inspissated juice
80 A LTITUI) E.
of the plant. There are three sorts of this, viz. Socotrina, hepatica, and cabal-
lina. The first of these, which is considered the best, comes from the island
Socotora, whence its name. It is of a glossy appearance, and in a slight degree
pellucid; if reduced to powder, it is of a bright golden colour. The hepatica
is so called from its liver colour, and is chiefly brought from Barbadoes in large
gourd shells. Its taste is intensely bitter and nauseous. The caballina is
º used as a medicine for horses, from which circumstance it derives
this appellation. It is coarser and more impure than the others, and has a
rank strong smell. The three varieties have, however, all been obtained from
the same plant, at Morviedro, in Spain. The first, from the liquid which flows
spontaneously from the incised leaf; the second, from the juice afterwards
extracted by pressure; and the third, by º the expressed juice with the
dregs of the former. Pure aloes are nearly soluble in water and in alcohol.
They are powerfully aperient, and in large doses produce much irritation: small
doses are tonic and aperient.
ALTITUDE. The height of any place or thing; one of the three dimen-
sions of solid bodies; elevation of the celestial bodies, &c. In geometry, the
altitude of a figure, or a solid, is the perpendicular distance between its vertex
and base. The altitude of buildings, trees, &c. may be measured like that of
geometrical solids, from the base to the vertex, but the altitude of lofty moun-
tains or elevated plains is reckoned from the level of the ocean. There are
various means for determining altitudes, such as geometrical construction; by
observation of shadows; by trigonometrical calculation; and by the use of the
barometer. For an account of the various instruments employed as quadrants,
sextants, theodolites, barometers, &c., with the methods of applying them, con-
sult their respective names. The altitude of terrestrial bodies may be either
accessible or inaccessible. When the object viewed is accessible, and on the
same horizontal plane as the observer stands, its altitude may be found in the fol-
lowing way: Provide two deal rods, one longer than the other; fix the shorter
one vertically in the ground, and having placed your eye at its top, let an
assistant move towards the tower in a direct line, till the top of the second rod
is seen on a line with the summit of the object whose altitude is required. Next
measure the distance between the two rods, and also between the shorter rod
and the tower. Then say, as the distance between the two rods is to the dis-
tance of the shorter rod from the tower, so is the difference in length of the
rods to the difference between the height of the tower and the shorter rod.
Hence, if to this difference we add the length of the shorter rod, it will give
the altitude required. The result may, however, be more conveniently, as well
as more accurately obtained, by means of a quadrant, or other instrument to
measure angles, in the following manner. Measure the distance of the observer's
place from the foot of the tower, and take the angular elevation by means of
the quadrant; then say, as the cosine of the observed angle is to the measured
distance, so is the sine of the observed angle to the altitude required. Altitude,
in astronomy, signifies the angular distance of a celestial body from the horizon,
measured on a vertical circle. The altitude is either true or apparent, accord-
ingly as it is measured from the rational or the sensible horizon. The observed
or apparent altitude varies from the true on two accounts. First, the body is
seen from the surface of the earth, instead of from the centre, which causes it
to appear lower than its true place, by a quantity which is denominated the
horizontal parallax. Secondly, the rays of light by which the body is perceived,
are refracted by the terrestrial atmosphere, and, consequently, it appears higher
than it otherwise would. To obtain the true altitude, therefore, of a celestial
body, we must add the parallactic angle to the apparent altitude, and from the
sum subtract the refraction. The fixed stars, from their great distances, have
no sensible parallax, and hence the preceding remark applies only partially to
them. But the difference between the true and apparent altitude of the moon,
is, from its proximity to us, about 520. Altitude of the eye, in perspective, is
the height of that point in the perspective plane which would be made by a right
line drawn from the eye and cutting the plane perpendicularly.
A LTO FAGOTTA, or Octave Fagotta. A new musical instrument. ſt is
AI, U.M. - 81
very Sonorous, the upper notes approximating Gº C
~! -- . ~l -- a-- al- - - - ~ ſº l, ,---
closely to those of a horn, theºgh :::::ch Sefter;
the lower notes blending very harmoniously with
those of the voice, piano-forte, &c. The compass
of the instrument is three octaves, commencing
with the C in the second space bass clef, or four
notes lower than the fourth string of the violin,
continuing to the C the second ledger line above
the treble stave, with their intermediate semi-
tones. It is played with a reed and mouth-piece
similar to a clarionet. The annexed represen-
tation, although like the small bassoon, differs
materially in its tone and compass. There are
three keys and key-holes on the opposite side to
that delineated.
ALUDEL. The recipient of vapourizing sub-
stances subjected to the operation of heat. They are
generally of earthenware, and of various forms and
size. Sometimes tubes are employed as aludels, and
sometimes vessels of large capacity, according to the nature of the substance
which is to be condensed in them. The process of condensing the product is much
facilitated by keeping the aludel constantly cool by wet cloths or a stream of water.
ALUMINA. A primitive earth existing in great abundance in clays, earths,
ochres, rocks, &c. Soils containing much of this substance are called argil.
laceous. It is found in a state of great purity in many precious gems, as the
sapphire, topaz, emerald, garnet, beryl, &c. When pure, it is of a white colour,
pulverulent, and soft to the touch. It adheres to the tongue, but is tasteless.
It is insoluble in water, but is readily dissolved by acids, and also by caustic,
potash, or soda. . If moistened with water, a very ductile and tenacious paste
is formed, which, by heating, becomes exceedingly hard, and is, therefore, ex-
tensively employed in the manufacture of porcelain, earthenware, and all kinds
of pottery. Bricks, tiles, crucibles, and stone ware, contain large quantities of
alumina. It is infusible, per se, in the strongest heat of a furnace, but small
quantities may be fused by the oxy-hydrogen blow-pipe. If mixed, however,
with certain proportions of lime and silica, it fuses readily. Pure alumina may
be obtained easily from the triple salt, containing ammonia instead of potash,
by heating it intensely. The acid and the alkali are dissipated by the heat, and
the pure earth remains. It is usually procured by adding a small quantity of solu-
tion of bicarbonate of potash to a solution of common alum, which precipitates
the iron contained generally in that salt. The filtered liquid is then to be added
to the liquid ammonia, which combines with part of the sulphuric acid of the
alum, and precipitates the earth in a spongy mass. This must be washed fre-
quently in distilled water, and then heated to dryness. According to the expe-
riments of Sir H. Davy, it appears, that, like the other earths, alumina
is a metallic oxide. By passing potassium in vapour over alumina heated to
whiteness, a great part of the vapourized metal was converted into the alkali
potash :--a decisive proof that alumina contains oxygen. By treating the
chloride of aluminum with potassium, a grey powder is obtained, which, by
burnishing, acquires metallic lustre. This powder burns with much splendour
if heated to redness, and is converted to alumina by absorption of oxygen. The
metallic base is called aluminum; and it is found that 100 parts combine with
8 of oxygen. Alumina has the unusual property of contracting by heat, and
in pretty exact proportion with the intensity applied. On this property, the
ingenious Mr. Wedgewood constructed his pyrometer for estimating very high
temperatures. See PyRoxeter. This useful earth has a powerful affinity for
colouring matter, and also for greasy substances. Fuller's earth and pipe-clay
owe their useful properties to the large quantities of alumina they contain.
ALUM, a triple salt of great importance in the arts, is composed of sulphuric
acid, alumina, and potash. It is sometimes found native, but only in small
quantities, and is artificially manufactured, chiefly from the mineral called alum-
__*2+

82 ALUMI.
slate. This is found in great abundance in the north-east district of Yorkshire,
more particularly between Whitby and Stockton. In the reign of Queen
Elizabeth, Sir Thomas Chaloner established a manufactory of alum at Gis-
borough, in Yorkshire, and engaged several expert workmen, acquainted with
the mode of manufacture, from the dominions of his Holiness the Pope, who
fulminated bulls and anathemas against him and them in vain. The alum-
slate is also found in abundance at Beckel, in Normandy. There are other
aluminous minerals from which alum may be obtained; but none appear so well
adapted, nor so plentiful, as the alum-slate, or aluminous schist. The mineral
from which alum is manufactured, is broken into small pieces, and placed on a
bed of fuel, until it is about 4 feet high. The fuel is then ignited, and as the
calcination proceeds, more of the mineral is added from time to time, until an
enormous pile, sometimes equal in area to 200 square feet at the base, is formed
The combustion proceeds so rapidly, that it is necessary to prevent access of air,
by plastering the crevices with small schist (alum-slate,) made into a lute with
water. It requires about 130 tons of the mineral to produce one ton of alum.
When the calcination is effected, the residue is digested in pits containing large
quantities of water. The liquid is withdrawn by pumps, and added to fresh
calcined ore. This is repeated until its spec. grav. becomes about 1.15.
This saturated liquor is sometimes placed in pits, to deposit sulphate of lime, and
other earthy matter, which may contaminate it, and sometimes boiled to pro-
duce the same effect. The purified liquid is then concentrated at a boiling heat,
in large sloping leaden pans. This is then removed to a settling cistern, and a
solution of muriate of potash, or the impure alkali of the soap-maker, is added
to it. The quantity necessary is ascertained by experiment with a small portion
in a basin. The alkaline solution reduces the spec. grav. from 1.4 or 1.5
to 1.35. The quantity of alkali required is, therefore, easily ascertained by an
hydrometer. If the spec. grav. of the liquid be more than 1.35, it does
not yield crystals, but a solid magma resembling grease, and it becomes
necessary to reduce it and re-crystallize. Urine is sometimes added for this
purpose; it is crystallized in the usual manner by slow evaporation. These
crystals are purified by washing and boiling in a leaden vessel. The saturated
solution is then poured into casks, and in about a fortnight the casks are
unhooped and taken to pieces, the alum remaining in a solid mass. This last
process is called roching. It is calculated that 22 tons of muriate of potash,
or 31 tons of the black ashes of the soap boiler, or 73 of kelp, are necessary
to make 100 tons of alum. Ammonia may be employed instead of potash, but
it is more expensive. The impure sulphate of soda formed in the manufacture
of aqua fortis, may be economically employed in the manufacture of alum, as
it contains two out of the three ingredients necessary to its formation. Th
celebrated Chaptal manufactured alum artificially in France to a great extent.
A chamber of very large dimensions was constructed of masonry, and floored
with brick; the bricks being cemented with a composition of pitch, wax, and
turpentine. The roof was of timber, but the planks were closely grooved into
each other, no nails being employed. Lastly, the whole of the interior was
covered with a thick coating of the above-mentioned cement, applied as hot as
possible. The purest and whitest clay is then, after calcination, strewn on the
floor, and sulphur burned in the chamber. By this process sulphuric acid is
formed, which in a few days saturates the alumina of the clay, converting it
into sulphate of alumina. This is known by the efflorescence that takes place.
The salt is then removed and exposed to the air, that the acid may penetrate
more effectually the alumina. It is then lixiviated, treated with potash, and
crystallized as before described. One of the most ancient manufactories of
alum was at Roche, in Lyria, whence is derived the term Roche-alum.
According to the analysis of Berzelius alum consists of
Sulphuric acid . . . . . . . . . . . . 34.33
Alumina . . . . . . . . . . . . . . . 10.86
Potash . . . . . . . . . . . . . . . . 9.81
Water . . . . . . . . . . . . . . . . 45.00
AMAH) OU 83
Or, Suiphate of alumina . . . . . . . . . 36.85
-- 1. - 4 - ~ & T ~ -u (Y u ºr
Julpuave V1 J. U UCLS iſl º e º e s e e Ji C. lu)
Water - it e º e º e e • 2 e º e º & 45.00
100.00
The taste of alum is rather sweet, but astringent. It is a super-sulphate, and
reddens the vegetable blues. The spec. grav. is about 1.71. It is soluble
in 16 parts of water at 600, and in #ths of its weight of boiling water. By long
exposure to air, the surface effloresces, but the interior will remain a long time
unchanged. A moderate degree of heat expels its water of crystallization, but
an intense heat decomposes it, by separating a great part of its acid. The alum
of commerce generally contains much impure matter, particularly if kelp or
urine has been used in the manufacture. The sulphate of iron is, perhaps, the
most injurious foreign ingredient in its composition; this may be detected by
ferro-prussiate of potash. Alum is of great use and importance in many pro-
cesses of the arts. It is very extensively employed in dyeing, as a mordant.
Most of the vegetable colours employed in dyeing have no affinity for the
material intended to be dyed. In most of these cases alum is employed as the
intermediate medium by which the colouring matter may be fixed, as it has an
affinity both for the material and the colouring matter. An acetate of alumina
is frequently employed by the dyer, instead of the ordinary sulphate. The
acetate does not act so corrosively on delicate articles as the common alum,
and its affinity for some colours is greater. It is easily prepared by the double
decomposition of a solution of the sulphate of alumina and potash, and a solu-
tion of the acetate of lead. When these two solutions are mixed together, the
sulphuric acid of the alum combines with the lead, forming an insoluble preci-
pitate, which is sulphate of lead, while the liberated acetic acid unites with the
alumina and potash, forming the required acetate, which is separated by filtration
from the solid substance. If paper, linen, or wood, be soaked in a solution of
alum, it is rendered nearly incombustible, and less liable to be affected by mois-
ture. Paper thus prepared is advantageously employed in wrapping gunpowder
and is also useful in whitening silver. Alum has the property of hardening
tallow, for which purpose it has been sometimes advantageously employed. It
is used with much success in the preparation of skins for tanning, giving them
firmness after they have become flaccid by immersion in the lime pits. Turbid
water is rendered limpid and transparent by the addition of a small quantity of
alum in solution; its purity, however, is by no means promoted by the process.
It is usefully combined with the salt by which cod fish are cured, as it prevents
a deliquescence which would otherwise take place. It is used in the manu-
facture of London bread rather extensively, as it enables the baker to employ
flour of inferior quality; the alum promotes a white colour and closeness of
texture in the bread, - qualities much admired, although they generally indicate
impurity. It improves the colour of the beautiful pigment, Prussian blue, and
is extensively employed in the preparation of that article. In medicine it is
administered as an astringent and tonic, and also as a collyrium. Alum, deprived
by heat of its water of crystallization, which, in medicine, is called alumen ustum
(burnt alum), has been greatly extolled as a remedy in cases of colic, and some
other disorders. A remarkable substance, called Homberg's pyrophorus, is
prepared from alum. Equal parts of alum and brown sugar are melted over a
clear fire, and stirred constantly until they become dry. When cold the mixture
is finely powdered, and placed in a phial coated with clay, having an open
glass tube luted into its neck. This is to be intensely heated in a crucible con-
taining sand, when gas will issue from the tube, which may be inflamed. When
this ceases to come over, the crucible is removed, and the tube stopped by
moistened clay until the bottle is sufficiently cold to be corked. The substance
thus formed is a black and light powder, which takes fire when poured from the
bottle into the air. If poured into oxygen gas a more vivid combustion takes
flace.
AMADOU. This substance is, perhaps, better known by the familiar appel
S4 AMBERGRIS.
.ation of German tinder, and is chiefly employed in procuring a º speedily,
as it ignites immediately with a feeble spark from the flint and steel, or by con-
densation of atmospheric air, and burns with slow and smouldering heat for a
considerable time. It is formed of a spongy excrescence, or mushroom, found
on old trees, particularly the oak, ash, and fir. This is washed and boiled in
fair water, and afterwards beaten by a mallet until it resembles very spongy
leather; it is then soaked in a saturated solution of saltpetre, and dried in an
oven. A good substitute for this may be formed of coarse brown paper, soaked
in the solution of saltpetre, and dried in an oven.
AMALGAM. A combination of mercury with any other metal.
AMBER. A hard, solid, semi-transparent substance, found in several
mines of Prussia, in a bed of argillaceous mineral. It is also found in Poland,
France, Italy; on the shores of the Baltic and Mediterranean, in the neighbour-
hood of London, and in various other parts. It is generally considered to be
of vegetable origin, and to be composed of bituminous vegetable matter in a
state of congelation. The extraordinary property which amber possesses of
attracting, when excited by friction, light bodies, such as feathers, bits of
§. pith, dust, &c., was known to Thales, the celebrated philosopher of
iletus, who flourished 600 years before the birth of Christ. The Greek term
for amber is election; and from this word is derived the title of our modern
science, electricity, the effect of excited amber in attracting light substances,
being attributed to its elective powers. This mineral is found of various
colours, but the most abundant is of a deep yellow or orange. When broken,
the fracture is smooth and glossy, and it is susceptible of a beautiful polish. If
gently rubbed, it emits a peculiar and agreeable odour. At a temperature of
5500 Fahr. it melts, and its transparency is destroyed. It is insoluble in water;
but alcohol, if highly rectified, extracts a small quantity of its colouring matter.
Sulphuric acid will dissolve it, and it may be then precipitated by water. Pure
caustic alkalies also dissolve it, and some of the j oils. Various speci-
mens of amber have been found containing portions of animal, vegetable, or
mineral matter, imbedded in the mass. This fact seems to prove that it has
once been in the fluid state. From the appearance of insect remains in amber,
it would seem that they have attempted to escape from a viscid or congealing
mass. In some, the legs, or wings, only, have been found, which seems to prove
that the animal has been entangled in the viscid mass, and has left the fragile
parts of the body in attempting to wade through it. Drops of water, leaves of
plants, native gold, silver, and various other substances, have been found imbedded
in amber. Dr. Girtanner promulgated a very ingenious opinion on the formation
of amber, which appears plausible. He imagined that a species of ant called
formica rufa, formed this substance by the deposition of their peculiar wax, or
honey. These ants are found in immense numbers in the pine forests, where
amber is obtained in the mineral state. The wax, although soft, hardens by
immersion in salt water, and then bears a great resemblance to amber. Dr.
Brewster, however, considers, from the optical properties of amber, that it is
established beyond doubt, to be an indurated vegetable juice. By careful dis-
tillation, an empyreumatic oil, equal to one-third in weight of the amber, is
obtained. This oil is brown and thick if a strong heat is applied, and requires
re-distillation; but if the heat do not exceed 212, and water be employed, it is
limpid and colourless. It is used in medicine as an antispasmodic. The spec.
grav. of amber varies from 1.065 to 1.100. For its use in varnish-making, see
WARNISH.
AMBERGRIS, or AMBERGREASE. A solid, opake, fatty substance, found
on the sea-coast, or sometimes floating on the sea, chiefly in the tropical
regions. It is of various colours, but generally of a deep ash-coloured yellow.
It is most frequently obtained in small fragments, but large masses, weighing
from 100 to 180 lbs. have been found. It has frequently been discovered in
the intestines of the spermaceti whale, and is supposed to be the cause, or the
result of disease in the animal. Healthy fish, which void their excrements
when they are hooked, seldom contain amber; but diseased fish, unable to per-
form this function when caught, generally yield it; and it is almost always found
AMMON I.A. 85
in the faeces of the whale when dead and floating on the waters. There can
be little doubt that this substance is formed in the intestines of the animal, not
swallowed by it as some have supposed; for no large piece has yet been found
in the whale, which does not contain the beaks of the Sepia octopodia, the com-
mon food of the spermaceti whale. When first obtained, ambergris has the
foetid smell peculiar to the faeces of the animal; but after a short exposure to
the air and washing, its odour is fragrant, and is increased by heating. It is
not a little extraordinary that Mr. Homberg obtained, by long digestion of
human excrement, a substance which possessed, in a very intense degree, the
perfect smell of ambergris. The spec. grav. of ambergris varies from 0.780
to 0.926. It melts at 144° Fahr. and at 2120 Fahr. is volatilized in the form
of a white vapour. If thrown on hot coals, it burns and is entirely dissipated.
It is not soluble either in water or the acids. Ether, ammonia, and oil,
dissolve it, but alcohol acts only on a portion, and is therefore useful in analyzing
it. Caustic alkalies combine with it and form a soap. According to La Grange,
it is composed of adipocere resin, benzoic acid, and coal. By later analysis it
has been found that some specimens do not contain benzoic acid. The alcoholic
solution is used in cosmetics, &c., to communicate its peculiar odour.
AMETHYST. A natural gem, of a violet colour and great brilliancy, as
hard as the ruby or Sapphire, from which some say it only differs in colour. The
Asiatic are of a deep purple hue, and are deemed the most valuable. The
German are violet. Some amethysts are, however, made colourless by art,
when they are often mistaken for diamonds; the superior hardness of the
latter will, however, enable any person to detect the imitation.
AMMONIA. A powerful alkali, sometimes called the volatile. In its pure
state it is a gas transparent and colourless, and possessing all the mechanical
properties of ordinary atmospheric air. . Its smell is pungent and suffocating,
and its taste extremely caustic. It extinguishes combustion, and immediately
destroys animal life. One hundred cubic inches weigh 18.16 grs. Its spec.
grav. is 0.5954. . If the gas is passed through an ignited porcelain tube, con-
taining iron, it is decomposed, and its volume doubled; it is then found to con-
sist of 13 volume of hydrogen, and 3 volume nitrogen, which are condensed
into the bulk of one volume as ammoniacal gas. It is rapidly absorbed by cold
water, which, when impregnated with gas, is called liquid ammonia, or spirits
of hartshorn. At a temperature of 50, water absorbs about 670 times its
volume of the gas, and its spec. grav. is reduced to 0.875. This liquid, by
heating, parts with the ammoniacal gas, hence it is called the volatile alkali.
The manufacture of liquid ammonia is a very important one. As this alkali is
very extensively employed in medicine, chemistry, and the arts, we shall,
therefore, briefly describe the process. Into a retort connected with a series of
Woolfe's bottles, put two parts of slaked lime, mixed with one part of muriate
of ammonia (sal ammoniac). The Woolfe's bottles must be filled with pure
water, and if they are surrounded by cold water, frequently renewed; if by ice,
a more highly saturated liquid will be obtained. The muriate of ammonia is
decomposed by the lime, and the ammonia passes into the water in the bottles
in the state of gas, where it is immediately absorbed. The addition of hot
water, and application of moderate heat, ensure complete decomposition of the
salt. The liquid ammonia may be obtained by a more direct process, but not
so economically. The following mode is recommended by Mr. R. Phillips, as
being superior to that recommended in the London Pharmacopoeia. Pour half
a pint of water on 9 oz. of well burnt lime, and when it has remained in a close
vessel an hour, add 12 oz. of sal ammoniac, and 3% pints of boiling water.
Filter the solution when cool, and distil from it 20 fluid oz. This will have a
spec. grav. of 0.954, which is as strong as it can be conveniently kept. The
spec. grav. of liquid ammonia is a sure test of its strength. That above-men-
tioned will contain about 11 per cent. of ammonia. If the spec. grav. be .850,
the liquid will contain about 35 per cent. ; intermediate densities indicate
intermediate proportions of ammonia. The muriate of ammonia, or sal ammo-
niac, from which the above-described liquid is obtained, was formerly brought
from Egypt almost axclusively. In the neighbourhood of the temple of Jupitet
M
86 ANCHORS.
Ammon, were many inns for the accommodation of pilgrims and their camels.
From the sublimed dung of these animals the salt was obtained, and its name
was derived from the locality of its manufacture. In modern times, ammonia
has been procured by the dry distillation of bones, horns, and other animal
matters; and, more recently, from the waste liquor of the gas works, which con-
tains large quantities of impure ammoniacal salts. The muriate of ammonia
is employed in chemical analysis, in dyeing, and in tinning or soldering. It is
the most delicate test for the presence of platinum, and is generally used by the
chemist to precipitate that metal from its combinations in solution. There are
many other valuable salts of ammonia, the most important of which are the
nitrate and carbonate. The nitrate, when heated to 4000 Fahr. is decomposed,
and yields the nitrous oxide, or laughing gas, in abundance. It is also used in
the preparation of frigorific mixtures; if mixed with an equal weight of water,
the thermometer sinks above 300 Fahr. The carbonate is a useful chemical
agent, and is used in medicine as a stimulant. This substance is the common
smelling-salts of the shops. All the salts of ammonia are decomposed at a red
heat. , Chlorine decomposes liquid ammonia, or the gas, with great energy.
If a bottle containing chlorine gas be brought in contact with the surface of
liquid ammonia, the hydrogen of the latter substance combines with the chlo-
rine, forming muriatic acid, which unites with another portion of ammonia, and
nitrogen is left in the bottle. If this experiment be formed in a dark room, a
flash of light will be seen at the moment of combination. If the mouth of a
bottle containing chlorine gas be brought in contact with the mouth of another
containing ammoniacal gas they combine with explosive violence, a flash and
report accompany the action, and the bottles are sometimes broken.
AMMONIAC GUM is a concrete gummy-resinous juice. This gum has a
nauseous sweetish taste, succeeded by a sensation of bitter, somewhat resembling
galbanum, but more grateful. It is usually brought from the East Indies, in
large masses composed of lumps, or tears; it acquires a yellowish appearance
on exposure to the air. When chewed, it softens in the mouth, and becomes of
a white colour. It may be partially dissolved in water, or in vinegar, with
which it assumes the appearance of milk; but the resinous part, amounting to
about one-half, subsides when suffered to rest. In medicine, it is prescribed for
removing obstructions of the abdominal viscera; in hysterical complaints, and
in long and obstinate colics, proceeding from viscid matter lodged in the intes-
times. Externally, it is used for the purpose of discussing indolent tumours;
and, with a mixture of squill vinegar, forms a plaster sometimes successfully
applied in the case of white swellings.
ANACARDIUM. The cashew-nut tree; a genus of plants of the class
Enneandria, and order Monogynia. At one extremity of the fruit of this tree
there is a flattish kidney-shaped nut, between which and the shell is a small
quantity of liquor, which is useful for marking linen, being very black and
durable.
ANACLASTIC GLASSES. A kind of somorous glasses, chiefly made in
Germany. They have the property of being flexible, and emitting a vehe-
ment noise by the human breath. The amaclastic glasses are a low kind of
phials, with flat bellies, resembling inverted funnels, whose bottoms are very
thin, scarcely surpassing the thickness of an onion-peel; this bottom is not
quite flat, but a little convex. On applying the mouth to the orifice, and
gently inspiring, or, as it were, sucking out the air, the bottom gives way with
a tremendous crash, and the convex becomes concave. On the contrary, upon
expiring or breathing gently into the orifice of the same glass, the bottom,
with no less noise, bends back to its former place, and becomes gibbous as
before.
ANACLASTICS. That part of Optics which considers the refraction of
light, and is commonly called Dioptrics.
ANCHOR. A heavy curved instrument, used for retaining ships in a required
position. The forms of anchors, and the materials of which they are made, are
various. . In many parts of the East Indies the lower part of the anchor is
formed of a cross of a very strong and heavy kind of wood, the extremities of
ANCHORS. 87
which are made pointed. About the middle of each arm of the cross is inserted a
long bar of the same wood, the upper ends of which converge to a point, and are
secured either by ropes or an iron hoop, and the space between the bars is filled
up with stones to make the anchors sink more deeply and readily. In Spain,
and in the South Seas, anchors are sometimes formed of copper, but generally
in Europe they are made of forged iron. Anchors may be divided into two
classes—mooring anchors, and ships' anchors. Mooring anchors are those
which are laid down for a permanency in docks and harbours, and are consi-
derably heavier than ships' anchors, from which they differ in form, having
sometimes but one arm, and sometimes, instead of arms, having at the extremity
a heavy circular mass of iron and no stock; these latter are called mushroom
anchors. The general form of ships'
anchors is shewn in the annexed
figure. a is a long bar of iron,
called the shank, from the lower
extremity of which branch two
curved arms b b in opposite direc-
tions, and forming an angle of 600
each with the shank. Upon each
arm, towards the end, is laid a
thick triangular piece of iron c c,
termed the fluke. In the upper
end of the shank is an eye, through
which passes a ring d, to which the
cable is attached. The stock e is
composed of two strong beams of
wood, embracing the shank imme-
diately below the ring, and secured
together by iron hoops and tree-
nails; the stock stands at right :
angles to the plane of the arms, ©
and serves to guide the anchor in
its descent, so as to cause one of
the flukes to enter the ground.
Ships are generally provided with
three large anchors, named the
best bower, the small, and the
sheet anchor; a smaller anchor,
termed the stream anchor; and
another, still smaller, named the kedge, which hatter has generally an iron stock
passing through an eye in the shank, secured thereto by a key, or forelock,
which admits of its being readily displaced: its principal use is in changing the
position of a ship in harbour, and in an operation termed kedging. From the
great mass of iron in large anchors (some weighing from 3 to 4 tons), the per-
fect forging of them becomes a matter of much difficulty; as from the great
heat necessary to weld such masses, the iron is liable to become “burnt,” as it
is termed. Workmen also cannot always observe what is going on in the forge,
where the iron is exposed to ignition from the blasts of the bellows, or to the
presence of sulphur in quantity among the coals. When the welding of a large
mass, like the shank of an anchor, is to be completed by the sledge hammer,
the workmen are subjected to a scorching heat radiating therefrom, which
renders it impossible to make a very close inspection, and the consequence fre-
quently is, the beating up of cinders within the body of the iron. To this cause, and
to burning, may be often attributed the breaking of anchors, followed too fre-
quently by a distressing loss of lives and property. Many attempts have been
made of late years to construct anchors not liable to these defects, by dividing
the mass into separate parts, and by a more judicious arrangement. The
following is the invention of Mr. Hawkes, a surveyor of shipping, in the
Commercial-road, London.
Mr. Hawkes observes, “The anchors at present in use are made by forming
. Fº
ſº
| ||
I.


88 ANCHORS.
the shank and flukes separately; and by the rapid action of heavy hammers, they
are united or welded into each other, and the cable is fastened to a ring passed
through the shank sideways. The stocks, if of wood, are let or scored over
each side, and bolted and hooped over the shank of the anchor; if of iron, the
eye or hole for it is formed by punching a hole through the shank of the anchor;
the palms are made separately, and welded on to the flukes. The improvement
consists in making one fluke and half the shank in one length, and to bend them
to the form required, and then hooping the two halves together. This method of
making the anchor in separate parts, admits of the forming of a groove up the
middle of the shank, for a chain to pass through, and of an eye of great
strength for the reception of a wooden stock, which is also made in two pieces,
and passed into the shank in reverse directions; these having iron shoulders
abutting against the eye, are kept immovably in that position by being braced
together with an iron hoop at each end. The construction is shown in the annexed
engraving. a the cable ring;
b the eye which holds the
stock, made out of the whole
substance of the shank, by
bending each of the halves
into a semicircle, in opposite
directions. The anchor is
shewn to be divided into two
equal parts, by a line which
passes down the middle of
the shank, as at o o, e the
wooden stock, made also in
two equal parts (as before
described), and firmly se-
cured in their places by the
hoops and shoulders; d.ddd
are four strong hoops which
bind the shank together; the
upper one is made square,
and the others circular; a
portion of the shank is sup-
posed to be removed, to ex-
hibit the situation of the
chain which passes up the
centre, and is connected at
the upper end to the cable
ring, and at the lower end
to the buoy ring, f, in the
small separate figure, gives
a transverse section of the
shank of the anchor, show-
ing it to be of an oval form,
the longest diameter of which is in a line with the flukes; this figure conferring
upon it great strength to withstand the powerful strains to which an anchor is
frequently, exposed in that direction. h. h. are the palms, bolted to the respective
flukes, each of which is connected in one piece with a brace i i, passing in oppo-
site directions round the shank of the anchor, thereby strengthening the flukes
in a great degree, and giving a collateral support to each half of the anchor
# is a strong plate of iron bolted on to the crown; l the buoy ring.”
An anchor, differing materially in form and construction from the ordinary,
was invented by Mr. R. F. Hawkins, and is represented in the subjoined en-
gravings. The shank of the anchor a is forked at the lower part or crown,
into two parts or loops b and c, in each of which is formed a hole or eye;
between the loops is a block of iron d, termed a crown piece, having a circular
aperture to receive the arms, and a square aperture at right angles to the former,
into which is screwed a stout bar of iron e, termed a toggle, projecting equally

ANCHORS. 89
on each side of the crown piece; on the end of the crown piece, opposite to
that in which is inserted the toggle, is a ring f for the buoy rope. The arms
g h are formed in one piece, and before the palms i i are attached, one end of
the arms must be passed through the eyes in the loops of the shanks, and through
the eye of the crown piece; the palms are then to be put on, and must both
Fig. 2.
Fig. 3.
lie in the same plane; after which the arms are to be curved in the same plane
with the palms. The crown piece is firmly keyed to the arms, and the toggle
must be of such a length and form as to make it bear firmly against the fore
part of the fork in the shank, so as to prevent the crown piece and arms from
turning round upon it, and to retain them at an angle of 500 with the shank,
When the anchor is let go, one end of the toggle will come in contact with the
ground, which puts the flukes in a position to enter; and when the strain is
upon the cable, that end of the toggle which is upwards comes in contact with
the throat of the shank, and sets the anchor in the holding position, as shown
in perspective at Fig. 3. The advantage of this mode of constructing anchors
is, that both arms take the ground, and therefore the weight of metal may be
diminished, and yet an equal, if not a greater, effect be obtained; also as there
is no stock, and no projecting upper fluke, there is little risk of fouling, as it is
termed; that is, of the cable entwining round the arms. The only objection
which occurs to us, is the probability that, when at single anchor, it might not
so readily turn in the ground at the turn of the tide, as the ordinary anchor,
and therefore might be likely to trip; but for moorings we have no doubt that
it would be found very effective.
An anchor upon a similar principle, but of a somewhat different con-
struction, was invented by Mr. Soames, a front and side elevation of which
is exhibited in the subjoined cuts. In this anchor there is but one fluke a,
which is T shaped, and works on a pivot in a triangular frame, composed of
the two sides b and c, forged in one piece, and a stay d, which serves as
a stock; f f are loops, or eyes, for the recepticii of the chains that unite


90 ANCHORS.
the ring g, to which the cable is to be fastened. For general purposes,
this anchor is, perhaps, preferable to the former, it being free from the objection we
made to that one, as it admits
of detaching the arm, which
renders it more convenient
to stow away ; also, as the
shank is formed in two parts,
instead of one of equal area,
they are more easily forged,
soundly, and, consequently,
less liable to breakage.
The anchor invented by
Lieut. W. Rogers, R.N. is de-
serving of notice in this place.
Its main peculiarity consists
in its having a hollow shank,
formed out of six bars of iron,
of such a thickness as to in-
sure the forging of them per-
fectly sound for anchors of
the largest dimensions. The
construction we shall describe
with reference to the subjoined
figures. Fig. 1 represents
a side view of the anchor,
and Fig. 2 a plan of the stock. The two principal pieces a a are bent so
as to form a part of the arms or flukes; the other four are formed into a
hollow tube b b (as shown in section at Fig. 3) for a centre-piece, and the whole
y
Fig. 8. Fig. 4.
are firmly welded together at both ends of the shank. The intermediate parts
are secured by strong hoops i i, so that every piece must bear its proportion of the
entire strain. The patentee states, that so great is the strength thus obtained for
the shank, that both arms have been broken off by the testing machine, without
altering the shank in the least degree. On the 11th of June, 1829, an experi-
ment was made at the Gateshead iron-works, in the presence of several respect-
able ship-owners, when the patent anchor, weighing 9 cwt. 19 q1s. 4 lbs. broke
in succession the following anchors on the old construction, without receiving
the least injury; viz. one of 10 cwt. 3 qis, 4 lbs. for hempen cables; one of


ANCHORS. 91
10 cwt. 2 qes. 12 lbs. and one of 12 cwt., 4 lbs. for chain cables. In place of
the usual ring, there is a bolt and shackle c, Fºgg. and 4, when the anchor
is to be used with chain cables; but when hempen cables are to be used, a ring
d is connected to the shackle c by an additional shackle and bolt e. The anchor-
stock f may be formed either of a single piece, or of two pieces hooped together,
and is secured in its place as follows: The bolt and shackle c being withdrawn,
the small end of the shank is passed through the eye of the stock f (which is
defended by an iron plate g on each side); the collar h is then put over, and
the stock is keyed up against the hoop i by the forelock key k passing through
a hole in the shank; by this means the anchor may be stocked or unstocked
without the assistance of a carpenter, which is a great recommendation, as
a considerable length of time is required to stock an anchor in the common
way. These anchors have been pretty extensively adopted, and several parties
who have made trial of them have given satisfactory certificates of their effi-
ciency. In connexion with improvements on anchors, it may not be altogether
out of place to mention some improvements in the method of letting them go.
Two improved methods of letting go anchors are described in the Transactions
of the Society of Arts. The principle is the same in each, and consists in sup-
porting the end of what is termed the standing part of the cat-head stopper and
shank-painter, by bolts turning upon pivots, and retained in a proper position
by a catch, which being withdrawn, the bolt turns upon its pivot, and the stopper
slips off, by which means all risk of jamming the turns of the stopper (as in the
common method of letting go the running end) is avoided; the danger to the men
on the forecastle is done away, and the anchor can be let go at a moment's warning.
The arrangements in each of these inventions being the same, whether
applied to cat-head stoppers or shank-painters, we shall therefore show one in-
vention as applied to cat-head stoppers, and the other to shank-painters. The
subjoined cuts show Capt. Burton's method of letting go a cat-head stopper a
is the cat-head; b c a bolt, turning upon a pivot d, the end c forms an oblique
plane, and is held down by the clamp e turning upon a pivot f, the clamp being
secured by a hasp g and pin h. i is the standing end of the stopper, having an
eye formed in it, which passes over the end b of the bolt b c ; the other end of
the stopper passes through the ring of the anchor, and over the thumb-cleat k,
and is made fast round the timber-head l. When it is required to let go the
anchor, a hand-spike is inserted between the thumb-cleat k, so as to nip the
clamp e, and the hasp g is cast off; then upon withdrawing the hand-spike, the
bolt being no longer held by the clamp e, turns upon its pivot d, by the weight
of the anchor on the stopper, and the eye of the stopper slips off the end of the bolt,
The following cut represents Mr. Spence's invention for letting go a shank
painter. Fig. 1 is an elevation, and Fig. 2 the plan, a is a cast-iron carriage,

92 ANEMOMETER.
bolted through theship's side,
and supporting the hook, b Fig. 1. Fº
by a pin or pivot at c 5 de t
a lever turning upon a centre
f, the end d being formed
into a hook, which clasps the
upper end of the bolt b, the
lever being retained in the
position shewn in the plan,
by a pin g; h is part of a Fig. 2.
chain forming the standing
part of the shank-painter,
and supported by the bolt b.
To the other end of the chain is spliced the running part of the shank-painter
which passes round the shank of the anchor, and is made fast to a timber-head.
When it is required to let go the shank-painter, an iron bar is inserted into the
end e of the lever de, which is made hollow for the purpose, and the ping being
withdrawn, the lever is turned round its centre until the bolt is released from
the hook d, when it falls, and the chain end of the shank-painter slips off.
ANCHUSA. Yellow anchusa, or blue-flowered bugloss. The juice of its
corolla or flower, gives out, on the addition of acids, a beautiful green. An
infusion of these flowers is given in inflammatory bilious diseases.
ANIL. The plant from which indigo is prepared. See Indigo.
ANIME is a resinous substance, commercially, but improperly, called gum
anime; for, like resins, it is totally soluble in alcohol, and also in oil, while
water will not take up more than a sixteenth part by weight. There are two
kinds, distinguished by the terms oriental and occidental. The former is dry,
and of colours varying from green to red and brown. The latter is of a yel-
lowish white, transparent, and somewhat unctuous, tears, and partly in large
masses, brittle, of a light pleasant taste, easily melting in the fire, and burning
with an agreeable smell. The
spirit of the alcoholic solution,
when drawn off by distillation,
preserves the taste and flavour
of the anime; the distilled water
exhibits on its surface a portion
of essential oil. This resin is
much used in perfumery. It
has also been imagined to be of
important service in plasters, em-
ployed to relieve nervous affec-
tions of the head and other parts.
ANEMOMETER. An in-
strument for measuring the
strength or velocity of the wind.
Among various machines which
have been constructed for this
purpose, the following one has
been found to answer very well.
It consists of an open frame a b c,
supported by a shaft d, upon
which it turns by the action of
the wind upon the vane e. ff
are sails, fixed to one end of the
axis g, and disposed to be influ-
enced by the wind in the usual
manner. Upon this axis is also
fixed a conical barrel of wood hk,
on the smaller end of which k
is attached a line l, with a weight


ANEMOMETER. 93
appended to it. The wind acting upon the sails, causes the barrel to revolve,
and the line to be wound up on its superfices. To prevent any retrograde motion,
a ratchet wheel o is fixed to the base or larger end of the cone, having a clicker
falling into the notches as it revolves. It is evident that the power of the weight
will continually increase as the line advances towards the base of the cone, as
the weight acts at a greater distance from the axis or fulcrum ; consequently,
the variable force of the wind may be readily ascertained by fixing the line at
the smallest end, and marking the barrel with spiral lines, as taken up by the
coiling of the rope round its superficies, placing also between the lines numerals
to denote the force of the wind, which may be calculated with tolerable pre-
cision upon the principles of the lever. The diameter of the cone should be
such in comparison with its smallest end, that the force of the strongest wind
should have scarcely sufficient force to bring the line on to the base of the
COIle.
Although the instrument above described gives an accurate idea of the com-
parative force of the wind at different times, it does not point out the actual
force exerted on a given surface, nor can observations made with one instrument
in a particular place, be compared with observations made by another instru-
ment elsewhere. It is also cumbersome, and not portable. In the Philosophical
Transactions for 1775, Dr. Lind gives a description of a very ingenious portable
wind gauge, which indicates the actual force of the wind by the column of water
which it will support. This instrument consists
of two glass tubes a b c d, which should not be
less than 8 or 9 inches long, the bore of each
being about ; of an inch diameter, and connected
together by a small bent glass tube e of about only
} of an inch bore, to check the undulations of the
water caused by a sudden gust of wind. On the
upper end of the tube a b is fitted a thin metal
tube f which is bent at right angles, and has its
mouth open to receive the wind blowing into it
horizontally. The two branches of the tube are
at liberty to turn round a steel spindle g, which
passes through two slips of brass h i near the top
and bottom of the instrument. The spindle is
fixed into a block of wood by a screw in its bot-
tom. When the instrument is used, a quantity
of water is poured in until the tubes are about
half full, and the instrument being then held
perpendicularly, with its mouth exposed to the
wind, the water will be depressed in the tube a b,
and proportionably elevated in the tube c d, and
the distance between the surfaces in the two tubes
measured by a sliding scale of inches, and parts
h attached to the instrument, will be the height
of a column of water which the wind is capable
of sustaining at that time; and as a cubic foot of
water weighs 1000 oz. or 62% lbs. nearly, the
twelfth part of which is 5; lbs., therefore every
inch the surface of the water is raised, the force
of the wind will be equal to so many times 5; lbs.
on the square foot. This instrument shows the
force, but not the velocity, of the wind; but as
the force is as the square of the velocity, if the
velocity due to a given force be ascertained, a table of the velocities corresponding
to each inch the water is elevated, may be calculated and engraved upon
the scale of equal parts. The following table, showing the corresponding
height of water, velocity of the wind, and the force exerted tipon a square
#. of surface, has been calculated from some experiments made by Dr.
utton.
~
dº
;
:
;
i
i
ºi
|
*A*
* *

94 ANTI-ATTRITION.
Height of Water. Force of Wind. Velocity per Hour.
Inches. lbs. Miles.
+ . . . . . . . . . 1.3 . . . . . . . . . 18
# . . . . . . . . . 2.6 . . . . . . . . . 25.6
1 . . . . . . . . 5.2 . . . . . . . . . . 36
2 . . . . . . . . . 10.4 . . . . . . . . . 50
8 . . . . . . . . . 15.6 . . . . . tº e º º 62
4 . . . . . . . . . 20.8 . . . . . . . . . 76
5 . . . . . . . . . 26. . . . . . . . . . 80.4
6 . . . . . . . . .. 31.25 * * * * g e 88
7 & e s a n e º a 36,5 . . . . . . . . . 95.2
8 . . . . . . . . . 41.7 . . . . . . . . . 101.6
9 . . . . . . . & 46.9 . . . . . 108
10 . . . . . . . . . 52.1 . . . . . . . . . 113.6
ll . . . . . . . . . 57.3 . . . . . . . . . 119.2
12 . . . . . . . . . 62.5 . . . . . . . . . 124
ANISEED. A medicinal seed produced from a species of pimpinella which
grows naturally in Egypt, Syria, and other eastern countries. In France it is
cultivated for culinary and medicinal uses. Aniseeds are roundish and striated,
flatted on one side, and pointed at one end; of a pale colour, inclining to green.
They have an aromatic smell, and a pleasant warm taste. Their virtue is
entirely given out to alcohol, when it forms, combined with syrup, the well-
known cordial of this name.
ANNEALING. The process by which metallic, and other mineral produc-
tions, are converted from a brittle to a comparatively tough quality, presumed
to be caused by a new arrangement of their constituent particles. In a con-
siderable number of bodies that will bear ignition, it is found that sudden cooling
renders them hard and brittle, while, on the contrary, if they are allowed to
cool very gradually, they become softened or annealed. We have, however,
noticed several alloys of copper (brass in particular) in which sudden cooling
has the reverse effect, that of annealing it. The process of annealing requires
some address and experience to perform it in the best manner; and varies in
the degree of heat applied, as well as in the period of cooling, according to the
nature of the metal or other substance operated upon. In the annealing of
steel and iron, the metal is heated to a low redness, and suffered to be gradually
reduced in its temperature, covered up, on a hearth. Ovens are constructed
for this purpose, wherein the pieces of metal, according to their massiveness,
and the quality it is desired they should possess, are placed and retained at a
low heat for days, and sometimes weeks together. The annealing of glass is
performed precisely in the same manner. * -
ANNOTTA. The pellicles of the seeds of a lilaceous shrub. The annotta com-
monly met with among us, is moderately hard, of a brown colour on the out-
side, and a dull red within. It is used for giving an orange cast to the simple
yellows; as an ingredient in varnishes; and besides its use in dyeing, is em-
ployed for colouring cheese.
ANTHRACITE. A species of coal called by a variety of names, of which
the most common are, stone coal, blind coal, glance coal, Kilkenny coal. There
are several varieties, and they possess generally the property of burning without
flame or smoke. See CoAL, FURNAcE, and Stove.
ANTI-ATTRITION. A patent for a composition under this name was
taken out in this country some years back: it was introduced as a substitute for
oil or grease, in lubricating the axle-trees of carriages, and is, of course, equally
applicable to the rubbing parts of other machinery. Its composition is simply
a mixture of hog's lard with “black lead” (plumbago), in the proportion of four
parts of the former to one of the latter. It appears from a Munich journal,
that the manufacture of this article in Germany is conducted with more exact-
ness; ten and a half parts are there melted over a moderate fire, when two
parts of finely powdered and sifted plumbago are to be added by degrees, and
be well stirred with a wooden spatula, until the incorporation ºf the two sub-
AN WIL. 95
stances is uniform and complete; the mixture is then to be taken from the fire,
and the stirring continued until it is quite cold, to prevent the subsidence of the
plumbago. When this composition was applied by means of a brush in the
cold state to pivots and toothed wheels, the expense was, in consequence, found
to be reduced from six florins twenty-nine kreutzers, to one florin thirty
kreutzers.
ANTIMONY. A brilliant white metal of a laminated or striated texture.
It is very brittle, and cannot be rolled into sheets, or drawn into wire. The
spec. grav. of the metal, is 6.712; it melts at 8109, and crystallizes in pyramids
when cooling. At an intense heat it is volatilized. The ores of antimony are
chiefly found in the north of Europe. There are several varieties, but the sul-
phuric or grey antimony is the most abundant, and yields the metal of com-
merce. It is reduced to powder, and heated in a reverberatory furnace; the
melted sulphuret then flows from the infusible stony or earthy matter, and is
then smelted and purified. The metal is used in the manufacture of printers'
types, music plates, specula for telescopes, and is a component of several useful
alloys. See ALLoy. A difference of opinion exists among chemists respecting
the number of oxides of antimony, some being of opinion that there are only
two; others, among whom is Berzelius, that there are four. We shall only
describe here the two which appear indisputable. To obtain the protoxide,
dissolve the metal in muriatic acid, and pour it into a large quantity of distilled
water; this separates the protoxide as a white precipitate, which must be washed
with a weak solution of carbonate of potash, to remove any muriatic acid it may
contain. This is the basis of all the useful antimonial medicines. The per-
oxide may be obtained by digesting antimony in nitric acid, and drying the
white powder which results at a moderate heat. Antimony is soluble in most
of the acids, and combines also with chlorine, iodine, phosphorus, and sulphur.
If filings of the metal are thrown into a vessel containing chlorine gas, they
burn vividly. Basil Valentine first introduced this substance into medicine, and
is said to have performed many extraordinary cures by it. Its virtues he dis-
covered accidentally. Having thrown a preparation of it into a hog-trough,
the hogs were violently purged by it, but afterwards fattened with surprising
rapidity. Seeing this effect, it is said he administered it to his brother monks
in such quantities that they all died : the medicine was therefore called
anti-moine, or anti-monk. By more cautious and skilful use, he obtained for it
a great reputation; but in 1566 its employment in medicine was prohibited in
Paris by an edict of the parliament. The sulphuret of antimony was employed
in very early times by the eastern females, and even occasionally by men, for
the purpose of staining the eye-brow and lashes, and even the lids, to make the
eye appear larger. This practice is frequently alluded to in the Scriptures.
There are many valuable medical preparations of antimony, the most important
of which, perhaps, is the medicine called Dr. James's Powder. This is a compound
of protoxide of antimony, and phosphate of lime. The precise mode of pre-
paring it is not known to chemists; the pulvis antimonialis of the shops is, in
composition, similar to James's powder, but its effects as a medicine are not so
certain nor so powerful. Tartar emetic, or tartarized antimony, is a triple salt,
composed of tartaric acid, potash, and antimony. Powder of algaroth is the pro-
toxide of antimony precipitated from the muriate by water. Kerme's mineral is a
hydro-sulphuret of the metal. Antimony is much valued as a medicine for
cattle.
ANVIL. A large solid mass of iron, of indispensable use in smiths', as
well as many other workshops, for hammering or forging work upon. They
are made of various sizes, from the weight of a few pounds (or even ounces,) up
to many hundred weights each; , and they are much varied in form, to adapt
them to the nature of the work they are designed for. Their general figure is
that of a parallelopipedon, with its lowest side spread out at the corners to
steady its seat upon a wooden block upon which they are mounted, and confined
by large nails or staples. The face, or upper side, of most anvils are perfectly
flat and smooth, and are made of steel, and so hard as to resist the file. At
one end of the anvil is a “beak-iron,” which is a projecting piece, tapering to
96 A POLLONICON.
a point, for the purpose of turning or bending the metal under operation ; and
there are also one or more holes made on the face, for the convenience of
punching holes in the work, or for the reception of fixed cold chisels, stakes, or
indeed any kind of tool that it may be desirable to adapt to it.
APIARIES. A place where bees are kept; the term is considered to apply
to a collection of hives, and not to a single one. See BEEHIVE.
APOLLONICON. A musical machine, on the principle of the organ,
which, by peculiar modification of the pipes, produces an excellent imitation
of the tones of all the most admired wind instruments; the combined effect of
the whole being similar to that of a numerous and well-chosen orchestra. This
magnificent contrivance, unrivalled in this or any other country, is the invention
of Messrs. Flight and Robson, who spent five years in its completion; and as
a popular description of it has not yet appeared, and cannot fail to be acceptable
to the amateurs both of musical and mechanical science, we propose to give
such an account of the instrument as may serve to convey a general idea of its
construction. In the apollonicon, as in the organ, the sound is produced by a
current of air, urged by bellows, through several series of vertical pipes. In
the apollonicon there are two pair of bellows, placed below the floor of the
apartment in which the instrument stands; the wind from which passes through
a reservoir and a tube, called a wind trunk, into an air-tight compartment,
called a wind chest. The pipes which, by various modifications of their con-
struction, produce the sounds of the different instruments, are ranged in rows
one behind the other, parallel to the front of the machine, in the order of the
gamut, each note and half note having its separate pipe, and each parallel row
representing a different instrument ; the pipes producing the same note in
every instrument lying in a straight line from front to back of the instrument,
or parallel to its sides. Thus the pipes producing the note A on the flute,
clarionet, bassoon, &c., all lie in a line parallel to the sides of the instrument.
From the upper part of the wind chest proceeds a horizontal platform, termed
the bottom board, having a series of channels cut in its upper surface, cor-
responding to each note of the different scales, and extending longitudinally
from front to rear of the machine. Above the bottom board, and at right
angles to the channels, are a series of grooves, corresponding to the transverse
ranges of pipes, or the number of the different instruments in each groove, are
three slides, placed one over the other, and through all three are cut narrow
passages, opening into each of the wind channels in the bottom board.
Over the slides is placed the top board, into which the pipes are inserted,
communicating with the wind channels through the apertures in the slides.
The use of these slides is to cut off occasionally the communication of any
particular instrument with the wind chest, so as to cause that instrument to
cease playing, which is effected as follows:—the space between each aperture
in the slides is somewhat greater than the width of the wind channels, so as to
cover the channels completely, and thereby cutting off the communication with
the instrument to which the slide belongs. Only one slide in each set of slides
is in operation at one time; the apertures in the other two sets being over the
wind channels, and below the apertures of the instruments. One set of slides being
used when the instrument is played by the mechanical action of the machine,
another set is moved by pedals, and the third set by hand, when it is played by
the keys. At that end of each wind groove that opens into the wind chest, are
two hanging valves, called pallets, which admit the air into, or exclude it from,
the wind grooves; and the art of performing upon the machine consists in the
management of the pallets and stops before described; the air or tune being
produced by the pallets, and the stops regulating the instruments, upon which
the air is played. We shall now proceed to describe the means by which this is
effected.—The machine may be played in two ways, either by performers
seated at ranges of keys, as in other organs, or by mechanical means : and as
this latter method is the distinguishing character of the machine, and has called
forth so much ingenuity in its execution, we shall describe it first. The prin-
ciple is as follows:–to one set of the pallets is attached a series of wires (one to
each pallet) passing through holes in a brass plate in the bottom of the wind chest,
APOLLONICON. 97
waich are just sufficiently large to allow the wires to move easily, without
allowing the air to escape from the wind chest. These wires (60 in num-
ber, being one to each note of the scale of the machine,) are connected to
one end of a series of small steel levers, set in a frame below the wind
chest, the outer end of the levers resting upon the surface of a cylinder
somewhat longer than the key-frame; a number of small pins and bent
wires or brackets project a short distance beyond the circumference of the
cylinder, ranged in lines across the axis, and by the revolution of the cylinder,
one or more of these pins or brackets are brought in contact with the outer
end of the keys, which are thus raised, whilst the other end of the keys, and
the pallets corresponding, are proportionably depressed; the wind passes from
the wind chest into the wind passages. The length of time the pallets continue
open is regulated by the length of the brackets; and when, by the revolution
of the cylinder, the brackets come clear of the keys, the outer end of the key
falls upon the cylinder, the pallet is closed by a spiral spring, and the com-
munication with the wind grooves is cut off. Beyond the keys, and towards
the end of the key-frame, is a set of similar keys, moved by brackets on the
surface of the cylinder, similar to the former, only projecting somewhat more;
these keys (called shifting keys,) by an ingenious arrangement (which we shall
afterwards describe at length), give motion to an equal number of levers, each
one of which moves in or out one or more of the set of stops which are
governed by the cylinder, and thus opens or cuts off the communication of the
corresponding instrument or set of pipes. For the sake of simplicity, we describe the
brackets as ranged in lines standing right across the axis, which is not quite correct,
as, in this case, the same keys would be moved at the corresponding part of each
revolution of the cylinder, and consequently only very short pieces could be
performed, or the cylinder must be of an inconveniently large diameter. To
remedy this, the cylinder is allowed to move endways in its bearings, a space
equal to the distance between two keys; on its axis is cut a screw, containing
nine threads, and the bevelled edge of a lever, called a knife, taking in one of
the threads of the screw, the cylinder would be moved endways, at each revo-
lution, a space equal to the distance between two threads; or one-ninth of the
distance between two keys, at each revolution; and the ends of each key would
trace a spiral line on the barrel, likewise deviating from a straight line one-ninth
of the distance between two keys; thus nine revolutions of the cylinder would
be made before the spiral traced by one key could be brought under the next
key. Now the brackets and pins being ranged on the cylinder along these
spiral lines, it is clear a different key may be moved at each corresponding part
of a revolution, for nine revolutions, which renders the barrel equal to one of
nine times its diameter, in which the brackets should be placed in right lines
surrounding the cylinder; and as the cylinder revolves very slowly, it is suffi-
cient for the performance of most compositions. If it is required to repeat the per-
formance, the key-frame is turned back upon a hinge, which raises the keys clear
of the pins, and the knife being lifted out of the screw cut on the axis, the cylinder is
moved endways into its original position, the knife replaced in the screw, and the
key-frame again brought down to the cylinder, when the piece may be repeated.
Having thus explained the principles of the mechanical action of the machine, we
shall proceed to notice some of the details of the arrangement. There are three
cylinders, each 2 feet in diameter, and each having a separate wind chest and
key frame placed over it, furnishing wind to particular portions of the scale.
The main cylinder occupies the centre of the front of the machine; it is 8 feet
long, and comprises a range of five octaves: viz. from G G an octave below first G
in the bass clef up to G, and eighth above G in the treble clef. In a line with
this, and concentric with it, is another cylinder, 3 ft. 9 in. for the bass notes
extending from G G G, or an octave below the former, up to gamut G, being
two octaves. The third cylinder lies at the back of the machine, parallel to
the main cylinder; it is 8 feet long, and comprises two octaves, Below the two
front cylinders extends a shaft, or axis, having two pinions, which work in two
wheels, one on the end of each cylinder, and a similar shaft lies below the third
cylinder, in the rear of the machine; and beneath these shafts, and at right
98 APOLLONICON.
angles to them, is another shaft, extending from the front to the back of the
machine, having on it two endless screws working in worm-wheels on, the
two shafts; this last shaft receives its motion by a band from the driving-shaft,
(which has a fly-wheel, and is turned by manual labour), and causes the cylinders
to revolve. The key-frame is made in distinct pieces, to allow for the unequal
Fig. 1.
.*
24
::/
contraction of the wood, and any inequalities which may exist in the cylinder ;
and to take the weight of the key, it is supported on the evlinder by anti-friction
rollers. it remains now to explain the connexion of the finger-keys with the
pallets. The key-boards are five in number, the central largest comprising a

APOLLONICON.
99
scale of five octaves, and the smaller ones disposed two on each side of the
iarger, these containing a scale of thies octaves.
I'l- - - - - - - - -------|- ~ + -- - - -] :--
1 11ese rºley ºval us evanau 1.11
front of the instrument, and detached from it, so that the performers sit with
their backs to the instrument, and their faces to the audience.
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i 00 APOLLONICON.
fore end of the finger keys descend wires to the fore end of a series of levers
below the floor, and to the other end of these levers are attached wires, which
pass through holes in the wind chest, and are fastened to their set of pallets,
and thus the depression of the finger keys draws down the hinder ends of
the lower levers, and opens the pallets. Within reach of the performers at
the keys, are a number of levers for moving by hand the draw-stops as are
termed the slides which throw off or on any particular instrument; but, in
addition to these, are a set of pedals five in number, which move a set of stops,
called compound pedal stops. These are the invention of Mr. Robson, and
are for the purpose of enabling the performer suddenly to throw on or off
a number of instruments by a single movement, and thereby add greatly to the
brilliancy of effect. The operation of these stops requiring a figure for its elu-
cidation, will be deferred until afterwards. To enable the reader more fully to com-
prehend the foregoing description, we have subjoined two engravings, Fig. 1 being
a section of the machine parallel to the barrels, or to the front; and Fig. 2 a
section across the barrels, or at right angles to the former. In these figures,
we have not strictly adhered to the actual arrangement of the parts which are
used in the instrument itself, but have rather endeavoured to give a general
idea of the principle of the construction, which is all that our limits will allow.
In each figure the same letters denote similar parts. a a are the reservoirs
immediately over the bellows; b the wind trunk; c the wind chest; d d
strengthening bridges; e e pallets; ffff wind grooves or channels; g g g the
stops or slides; h h the groove board, into which are inserted the foot of the
pipes j jj; k the driving shaft, turned by a band l, from a wheel below the
floor; m m endless screws working into worm wheels n n on the transverse
shafts o o, pp pinions driving the cylinders q; r the knife or guide; s the key-
frame; t t anti-friction rollers; w w the keys; v v stops to prevent the keys
striking the cylinder; w w shifting keys with the connexion to their stops; a
connexion of the pallets with the finger keys; y connexion of draw stops; :
connexion of compound pedal stops. Having thus explained the general
mechanical arrangement of the instrument, we shall proceed to explain more
minutely the manner of throwing on or off; the different instruments or ranges
of pipes, both by the shifting keys, and by the compound pedal stops. The
Fig. 8. -- lºt - Fig. 4.
ºlº ºffij º º
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above cuts represent one of the shifting keys, Fig. 3 being a front view, and
Fig. 4 a side view, a represents a portion of the cylinder; 5 one of the shifting











APOLLONICON. 101
keys, kept in contact with the barrel by the spring c. On the spindle d is keyed
a T-shaped lever e, in the horizontal arms of which are two projecting studs ff.
with a wire passed through them from one to the other. A piece of brass g is
attached at its lower end to the key b, and the upper end passing between the
lever; the wire rests by one of its shoulders on one of the projecting studs; a
steel spring blade h is inserted at its lower end into a cleft in the piece g, and
passes through a slit in a stud in the lower end of the lever e, and by its ten-
dency to recover a right line in the direction of the arm, it forces the piece g
out of the perpendicular, so that it shall always rest against one or other of the
studs. k is an arm upon the spindle d, connected by a bar l to the lever (not
shown) which works the slide or stop. Now when the tooth of the key is raised
by one of the studs of the barrel passing under it, the other end of the key is
depressed, and drawing down the piece g, shifts the lever e into the position
shown by the dotted lines, and thus reverses the position of the slide. When
the stud has passed the key, the spring c returns the key to its former position,
and the piece g in rising is thrown by the spring h against the stud in the upper
arm of the lever e. The compound pedal stops are a most admirable invention
of Mr. Robson's, by means of which the performer is enabled to throw off in-
stantaneously a number of instruments, and to bring into play a number of
others, as the varying nature of the music may require, with an effect and pre-
cision equal to that of the best appointed orchestra. The mechanism is extremely
ingenious, as well as beautifully simple. The arrangement will be easily under-
stood by referring to the annexed cuts, which represent one set of pedal levers,
Fig. 5. Fig. 6.
Fig. 5 being a side view, and Fig. 6 an end view. On the upper axis a is a
number of arms b b acting upon slits in a corresponding number of slides c_c,
on the lower axis d is likewise one or more arms e acting on one or more slides
j; on the axis d is a tooth g acting upon a similar tooth h on the axis a , the
length of each tooth being proportional to the length of the arms b and d. k
is an arm, connected by wires and bell-cranks to the pedal beneath the key-
boards. Now upon depressing this arm, it will be seen that the arms b b and dd.
will move over equal spaces in opposite directions; one set of slides will there-
fore open the communication between the wind grooves and the instruments to
which they belong, and the other set will close the passages to which they belong,
and thus throw out of play the corresponding instruments; and there being five
of these compound pedal stops, an amazing variety of changes may be obtained
by varying the combinations of the slides. The whole number of the keys acted
upon by the cylinders is about 250. There are upwards of 1900 pipes, 45 draw-
stops, and 2 kettle-drums. To the musical amateur the following list of the
stops will doubtless prove interesting.
On the first cylinder,-
1. Open Diapason. 4. Principal. 7. Fiute.
2. Ditto ditto. 5. Twelfth. 8. Sesqui Altera.
3. Stop ditto. 6. Fifteenth. 9. Cornet—Trumpet.
On the second cylinder are two octaves of wooden pipes, of large dimensions,
termed double diapason pedal pipes: the largest is 24 inches long, and 23
O

| U2 AQUEDUCT.
square; this is 8 feet longer than the corresponding pipe in the great organ at
Haarlem. The range of the scale is from G G G to G.
On the third cylinder are the following stops,
Diapason, or Corni Stop. Trumpet. Hautboys.
Stop Diapason. Cremonas. Piccolais.
Violoncello. Flutes. Trumpets.
German Flute. Vox humana. Diapason.
Wood Fifteenth. Octave Flute. Principal, &c.
The mechanism is enclosed in a case, 20 feet broad by 18 feet deep, and
24 feet high. The front is divided into three compartments by pilasters of
Grecian Doric, surmounted by others of the Ionic order. Between the upper
pilasters are three paintings; that in the centre representing Apollo, and those
on the sides the Muses, Clio and Erato, somewhat larger than life, which do
much credit to the artist (Mr. John Wright) by whom they were painted. The
mechanical action of the apollenicon was first exhibited to the public in June,
1817, when the overtures to Anacreon and to the Clemenza di Tito were
performed by the cylinders in a style that called forth the most marked appro-
bation from large and scientific audiences. From that period to the present
time it has maintained its well-deserved popularity, and continues an object of
interest alike to the musician and the mechanist, offering to the former some of
the grandest combinations of harmony, and to the latter some of the most
curious and complicated specimens of his art.
AQUA FORTIS. The old and still popular name for nitric acid. The
article sold in the shops under this name is generally prepared by mixing
common nitre with an equal weight of sulphate of iron, and half its weight of
the same sulphate calcined, and distilling the mixture; or by mixing nitre with
twice its weight of dry powdered clay, and distilling in a reverberatory furnace.
Two kinds are found in the shops, one called double aqua fortis, which is about
half the strength of nitric acid; the other simply aqua fortis, which is half the
strength of the double. See AcID, NITR1c.
AQUA REGIS. This having been the first solvent that was discovered for
gold, the king of metals, was called by this name, signifying the king's water.
• The original and proper aqua regis is made by adding four ounces of common
salt to an avoirdupois pound of aqua fortis. Homberg says, aqua regis is of
#. strength to dissolve gold, when a bottle, holding sixteen ounces of water,
olds seventeen ounces of the acid; that is to say, when it is of the specific
gravity 1.062. -
AQUA TINTA. See ENGRAviNG.
AQUA VITAF. Ardent spirit of the first distillation has been distinguished
in commerce by this name. The distillers of malt and molasses spirits call it
low wines.
AQUEDUCT. A conduit for water, constructed of different materials, built
on uneven ground, for preserving the level of water, and conveying it from one
place to another. Aqueducts are distinguished into two classes; the visible, or
such as are built on arches across valleys and marshes, and the subter-
raneous, which are formed by piercing mountains, and conveying the water
below the surface of the earth. These constructions were formed of brick,
stone, &c., and covered either with vaulted roofs, or flat stones, which served
to shelter the water from the influence of the sun and rain. They were, in some
cases, paved, and, in others, the water was conveyed through a natural channel
formed in the clay. It was also frequently conducted by leaden pipes into
reservoirs of the same metal, or into troughs of hewn stone. Some aqueducts
are supported on single, others on double, or triple, ranges of arches. Of the
latter kind is the Pont du Gard in Languedoc, supposed to have been built by
the Romans, to convey water to the city of Nismes; that at Constantinople,
and that which, according to Procopius, was constructed by Cosroes, king of
Persia, near Petra, in Mingrelia, and which had three conduits in the same
direction, each elevated above the other. The Romans had many magni-
ficent aqueducts, surprising on account of their magnitude and number, as
well as their construction and length; some bringing water through a distance
AQUEDUCT, 103
of from thirty to one hundred miles, either upon a series of arches, or by means
of excavations through mountains and rocks. This is well expressed by Pliny
in the following language: “If we consider the incredible quantity of water
brought to Rome for the uses of the public, for fountains, baths, fishponds,
private houses, gardens, and country seats; if we represent to ourselves the
arches constructed at a great expense, and carried on through a long distance;
mountains levelled, rocks cut through, and valleys filled up; it must be acknow-
ledged that there is nothing in the whole world more wonderful.” . The waters
of the Tiber, with the wells and fountains in the neighbourhood, had supplied
the wants of the Romans for four centuries and a half, when Appius Claudius,
the censor, advised and constructed the first aqueduct. His example was
speedily followed, and the courses of rivers were thus changed and diverted
towards Rome, to supply the daily increasing wants and luxuries of the Roman
people. At certain distances, vents were provided, in order that the water,
which was accidentally obstructed in its progress, might be discharged till its
ordinary passage was cleared; and, in the canal of the aqueduct itself, there
were cavities into which the water was precipitated, and where it might remain
till its mud was deposited, and the water become clear. A considerable variety
was observable in the construction of aqueducts. The aqueduct of the Aqua
Marcia had an arch of sixteen feet diameter. The whole was composed of
three different kinds of stone; one of them reddish, another brown, and a third
of an earth colour. The entire edifice is 70 Roman feet in height. Above
them appeared two canals, the highest of which was fed by the waters of the
Tiverone, and the lower, by what was called the Claudian River. Near this
aqueduct, Montfaucon gives the plan of another with three canals; the highest
supplied by the Aqua Julia, that in the middle from Tepula, and the lowest
from the Aqua Martia. The arch of the aqueduct of the Aqua Claudia was of
hewn stone, very beautiful; that of the aqueduct of the Aqua Meronia was of
brick. Each of these was 72 feet high. The Aqua Appia deserves notice for
the singularity of its construction, it not being plain or gradual in its descent,
but much narrower at the lower than at the upper end. The consul Frontinus,
who superintended the aqueducts under the emperor Nerva, mentions nine, each
of which had 13,594 pipes of an inch diameter; and it is stated by Vigerus,
that, in the space of twenty-four hours, Rome received, by means of these erec-
tions, 500,000 hogsheads of water. In modern times, the aqueduct of Legovia
is considered the most magnificent. There still remain 159 arcades, wholly
consisting of stones, enormously large, and joined without mortar. These
arcades, with what remain of the edifice, are 102 feet high ; there are two
ranges of arcades, one above the other. In 1684, Louis XIV. caused an aque-
duct to be commenced near Maintenon, for carrying water from the river Eure
to Versailles; but the work was abandoned in 1688. This would, probably,
have been the largest aqueduct in the world, the whole length being 60,000
toises; the bridge 2,070 fathoms in length, 220 feet in height, and consisting
of 632 arches. The principal ancient aqueducts now in being, are those of the
Aqua Virginia, Aqua Felice, and Aqua Paulina. The quantity of water sup-
plied by the whole of the aqueducts in ancient Rome, is calculated to have
amounted to the enormous quantity of 50,000,000 cubic feet daily; which,
reckoning the population of Rome at 1,000,000, allows 50 cubic feet for the
daily consumption of each individual. The supply of water to London in 1790,
amounted to 2,626,560 cubic feet daily; and even at the present day, it does
not exceed 4,000,000 feet. This quantity, although found abundantly sufficient for
our use, is little more than a twelfth part of the quantity consumed by the Romans.
The daily supply of water to Paris is still less, being about 293,000 feet, or half a
cubic foot for the daily use of each inhabitant. The Greeks of the lower empire
simplified the general mode of conducting water, and reduced the expense to a
fifth part, chiefly by the introduction of the Soulerazi, or water-balance, a sort
of hydraulic obelisk. The water runs down a gentle slope in covered drains,
till it reaches an obelisk constructed of masonry, and rising up one side in a
narrow channel, discharges itself into a bason at the top, from which again, at
a level 8 inches lower, it descends by a similar channel on the other side.
104 AftCHIL.
The charge of the water-works at Constantinople is entrusted to a body of 300
Turks, and certain Albanese Greeks, who make it almost an hereditary pro-
fession. The supply for each person is stated to be about two-thirds of a cubic
foot, or 42 pounds daily. There are two ancient cisterns still extant in Con-
stantinople: the subterranean cistern, built of hand-brick, vaulted, and resting
on marble columns; and the cistern of 101 columns, anciently called Philoxene.
The latter consists of three rows of columns, one above another, and is capable
of holding five days' supply of water for the whole inhabitants of this spacious
city. Among the most modern must be noticed the aqueduct of Chirk, in Den-
bighshire, constructed by Mr. Telford for the purpose of carrying on the navi-
gation of the Ellesmere canal. It consists of 10 arches, supported by
pyramidal stone piers, and extends to about 600 feet in length. The summit
of the central arch is 65 feet above the level of the water.
ARABIC GUM. This gum, which flows naturally from the acacia, in
Egypt, Arabia, and elsewhere, forms a clear transparent mucilage with water :
it is insoluble in alcohol and ether. It is used in medicine, and is considered as
a specific against the strangury occasioned by blisters; it constitutes, under
particular forms, a nutritious food, and it is an important article in various
manufactures.
ARCH, or ARC. In geometry, a part of a curve line, as of a circle or an
ellipse, &c. Arch, in architecture, an aperture, the upper portion of which is
bounded by curve lines, as we see in porches, bridges, &c.; they are of various
forms, and are designated by various names, according to their figure, as
circular, elliptical, cycloidal, &c. Arch of equilibrium, in the theory of bridges,
is that arch which is in equilibrio in all its parts, and therefore equally strong
throughout, having no tendency to break in one part more than another. The
arch of equilibration is not of any determinate curve, but varies according to
the figure of the extrados; every different extrados requiring a particular
intrados, so that the thickness in every part may be proportional to the
pressure. The subject has occupied the attention of several eminent mathe-
maticians, and has been fully treated by Dr. Hutton, in his “Principles of
Bridges,” and in some of his tracts; where the proper intrados is investigated for
every particular form of extrados; and it shews, that in semicircular and semi-
elliptical arches, and, in fact, in all arches springing perpendicularly from a
horizontal line, the line of their extrados becomes assymptotical as it approaches
a perpendicular passing through the points from which they spring, and that
such arches require to be loaded infinitely over the haunches. But the
researches of mathematicians upon this subject, although they are not without
utility, have not been of any great service to the practical builder, who, guided
by a set of maxims which are the fruits of observation and experience, constructs
arches of immense span, differing widely from the form assigned by theory,
which are, nevertheless, stable and durable. This arises, perhaps, not from the
theory being false, but from its being imperfect; mathematicians calculating
the effects of gravitation only, without allowing for those of cohesion, friction,
and some other forces, which undoubtedly operate in an arch, although it is
difficult to estimate their several quantities. Hence in practice it is found
sufficient if the arch of equilibrium be comprised within the boundaries of the
voussoir, or stones, forming the arch, without its being necessary for either the
intrados or extrados to conform exactly to that curve. For good practical
views on this subject, we refer our readers to Gwilt's Equilibrium of Arches, and
to the article “Bridges,” in the Edinburgh Encyclopædia.
ARCHIL. A whitish lichen, growing upon rocks in the Canary and Cape
Verd Islands, which yields a rich purple tincture, fugitive, indeed, but extremely
beautiful. This weed is imported to us as it is gathered: those who prepare it
for the use of the dyer grind it betwixt stones, so as to thoroughly bruise, but
not to reduce it into powder, and then moisten it occasionally with urine, or
mix quick lime with the urine: in a few days it acquires a purplish red, and at
length a blue colour; in the first state it is called archil, in the latter, lacmus,
or litmus. The dyers rarely employ this drug by itself, on account of its
dearness, and the perishableness of its beauty. The chief use they make of
ARSENIC. 105
it is for giving a bloom to other colours, as pinks, &c., This is effected by
passing the dyed cloth or silk through hot water, slightly impregnated with the
archil. The bloom thus communicated, soon decays upon exposure to the air.
By the addition of a little solution of tin, this drug gives a durable dye;
its colour is at the same time changed toward a scarlet, and that is the more
permanent, in proportion as it recedes the more from its natural colour. Prepared
archil very readily gives out its colour to water, to volatile spirits, and to alcohol;
it is the substance principally made use of for colouring the spirits of ther-
mometers. As exposure to the air destroys its colour upon cloth, the exclusion
of the air produces a like effect in those hermetically sealed tubes,—the spirits
of large thermometers becoming in a few years colourless. The Abbé Nollet
observes (in the French Memoirs for 1742), that the colourless spirit, upon
breaking the tube, soon resumes its colour, and this for a number of times
successively; that a watery tincture of archil, included in the tube of ther-
mometers, lost its colour in three days; and that in an open deep vessei it
became colourless at the bottom, while the upper part retained its colour. A
solution of archil in water, applied on cold marble, stains it of a beautiful violet
or purplish blue colour, far more durable than the colour which it communicates
to other bodies. There is a large establishment at Glasgow for an article of
this kind, which is much esteemed; it is sold by the name of cudbear. Silks
thus dyed with it are said to be very permanent, of various shades, from pink
and crimson to a bright mazarine blue.
ARGAL. Crude tartar, in the state in which it is taken from the inside of
wine vessels, is known in the shops by this name.
ARG AND BURNERS. See LAMPs.
AROMATIC VINEGAR. An acetic solution of camphor, oil of cloves,
oil of lavender, and oil of rosemary; a sufficient quantity of each to make it
pleasant.
ARRACH. A spirituous liquor, imported from the East Indies; it is chiefly
manufactured at Batavia and at Goa, upon the Malabar coast.
ARROWROOT. The pure starch of a bulbous-rooted plant, growing in
the West Indies, and other warm climates. The starch of the potatoe has pre-
cisely the same properties, and, from the superior cheapness of the latter in
this country, it forms a common substitute for the foreign production, which is
difficult to obtain in the retail shops unadulterated. Under the article PotAtoE
will be found a full description of the mechanical process employed in extracting
the starch from that root.
ARTESIAN WELLS. A name given by the French, and extensively
adopted here, to artificial fountains, made by boring the earth, and permitting
- the confined water to rise. See BoRING THE EARTH.
ARCOGRAPH. An instrument for drawing a circular arc without a central
point. There are various ways of performing this, but the following is the most
simple, and is often practised by bricklayers and masons. Two nails are driven
into the face of the wall upon which the curve is to be struck, the nails being
at each extremity of the curve; two laths or straight rods are then nailed
together at such an angle as that the apex shall touch the crown of the arch
when the two sides are in contact with the nails at the extremities of it; then
if the apex of the laths be gradually moved round from one nail to the other,
the laths being kept continually in contact with the nails, a tracer placed at the
apex will describe the required arch. An instrument of this kind, invented by
Mr. Rotch, and rewarded by the Society of Arts, will be found very serviceable
for drawing upon paper arcs of very large circles, whose centres lie beyond the
limits of the drawing board. It consists of two straight rulers, connected by a
joint similar to that of a sector, in the centre of which joint is a socket to carry
the tracer. The two limbs are connected to two graduated arcs, sliding upon
each other, by means of which the limbs may be set to any angle so as to describe
an arc containing any required number of degrees.
ARSENIC. A brittle metal of a bluish white colour, possessing very little
lustre. By exposure to the atmosphere it becomes nearly black, and slightly
pulverulent. It is very fusible, and is frequently employed to assist the fusion
106 ARSENIC.
of other metals. At 3560 Fahr. it is volatilized in white fumes, which constitute
the arsenious acid, or white arsenic. It is from this substance that the metal
of commerce is obtained, and is imported in large quantities from Saxony, the
cobalt works of which supply Europe with arsenic. The ores of cobalt contain,
with many other impuritics, much arsenic. This is dissipated by torrefying
them when reduced to powder in a furnace with a long horizontal flue:
The arsenious acid becomes condensed in this, and is removed by condemned
criminals, the employment being very dangerous, and even fatal to life, on
account of the impossibility of preventing particles of this powerful poison from
entering the mouth or nostrils. When first volatilized, it is contaminated with
sulphur, &c., from which it is separated by mixing with impure potash, and
subliming again in close vessels. It then constitutes the white arsenic of the
shops. The metal is obtained from this by incorporating it with carbonaceous
matter, and heating in a vessel provided with a receiver, to condense the arsenic
which rises in vapour. The ores of arsenic are numerous and abundant, and it
is a component of an endless variety of minerals. The process of roasting the
ores of copper, iron, &c. is unhealthy, chiefly on account of the quantity of
arsenic liberated. The minerals called realgar and orpiment (sulphurets of
antimony) possess much beauty. Arsenic combines with oxygen in two pro-
portions, the first of which, the arsenious acid consists of arsenic 76 + oxygen 24.
The second arsenic, acid of arsenic, 76 + oxygen 40. Both these compounds
possess the characteristics of acid bodies; they redden vegetable blues, and
eombine with many salifiable bases, forming neutral salts. The first of these
deserves particular attention, as it is the fatal poison so frequently employed in
the destruction of human life by the suicide or the assassin. It is nearly inso-
luble in cold water, and is, therefore, generally taken in the state of turbid
mixture. It adheres with singular obstinacy to the coats of the stomach and
intestines, and produces speedy corrosion and inflammation. The symptoms of
the poison are generally manifested within a quarter of an hour after it has been
swallowed: these are sickness, pain at the stomach, thirst, burning heat in the
mouth and fauces, faintings, cold sweats, debility, and at last cramp, and contrac-
tions of the limbs. Most, and frequently all, of these symptoms are displayed by the
sufferer before death. The only medicines likely to be effectual, are sulphuretted
hydrogen water, and copious draughts of bland mucilaginous liquids. Carbonate of
magnesia and opium have been on more than one occasion found highly beneficial.
In cases of suspected poisoning by this mineral, the contents of the stomach,
or the ejected matter, should be carefully saved and digested in distilled water.
This must be filtered through porous paper, and, if highly coloured with beer,
coffee, or other description of food, a small quantity of newly prepared pure
animal charcoal, in powder, must be mixed with it until the colouring matter is
destroyed. A second filtration produces a limpid and transparent fluid, suscep-
tible to the action of tests, which must now be applied. To one portion in a
test-tube, add a small quantity of transparent lime-water; in a short time, if
arsenic is present, the fluids will become turbid and opaque. To another portion,
add a few drops of liquid ammonia, and a solution of sulphate of copper; this
will produce a bright green precipitate, which is the pigment called Scheele's
green. Pass a current of sulphuretted hydrogen gas through another portion,
which will convert the arsenic into a sulphuret of a lemon yellow colour. To
another portion add a few drops of ammoniated nitrate of silver, which will
throw down a golden yellow precipitate, the arsenite of silver. If all these
tests produce the effects here described, the corroboration will leave no room to
doubt that aresenic was present; but it is advisable, and especially where
human life depends on the testimony, to place the matter beyond the possibility
of doubt, by reducing the arsenic to the metallic state. This is effected by taking
any of the before-named precipitates, and, when carefully dried, mixing it with
about an equal quantity of black flux (finely divided charcoal and potash). A
few grains of this must be carefully placed at the bottom of a test-tube, so that
none shall adhere to the side. The flame of a spirit lamp must now be directed
by a blow-pipe against the matter in the tube, and, in a short time, the arsenie
will be sublimed, and coat the interior of the glass with the reduced metal of a
ASSAY. 107
shining grey colour; or any of the precipitates may, when dry, be placed on
a piece of ignited charcoal, when the arsenic will be volatilized, forming a dense
white cloud, and emitting a powerful odour, like that of garlic, which is peculiar
to this metal. Arsenic is a metal easily combustible, and, in some cases, burns
with singular intensity. . If a small quantity is mixed in a mortar with chlorate
of potash, a violent explosion takes place. When thrown into chlorine gas, it
takes fire spontaneously if finely divided. The spec. grav. of arsenic is 5.763.
A sulphuret of arsenic, called orpiment, is extensively used in dyeing. It is
prepared by digesting arsenious acid in muriatic acid, and precipitating by sul-
phuret of ammonia. It is of a bright yellow colour, and produces a permanent
dye. Arsenic is used for various purposes in the arts (see Alloy); it promotes
the fusion of other metals, and occasions many that are very refractory to melt
at low temperatures. It is employed in the manufacture of lead shot, which it
renders more brittle, and more easy to granulate.
ASAFCETIDA is the concentrated juice of a large umbelliferous plant, which
is found in several parts of Asia. The root is of a black colour, and resembles
a parsnip; on cutting this transversely, a thick white juice exudes, which, by
exposure to the air, becomes of a dark brown colour. The fresh juice has even
a more powerful odour than the concrete asafoetida, which resembles that of
garlic. The Persians, who export large quantities of it, are compelled to hire
vessels on purpose, as its effluvia penetrates every article on board, and spoils
many productions. Asafoetida is of a yellowish brown colour, of an acrid taste,
and powerful smell. It consists chiefly of gum, resin, and earthy matter. In
medicine it is used as a deobstruent, and sometimes as an anthelmintic, and is
useful in nervous and hysterical affections.
ASBESTOS (amianthus). A fibrous mineral, found in large quantities in
Corsica. It is also procured from Savoy, France, Scotland, Sweden, and other
places, but is nowhere so abundant as in Corsica. The fibres of asbestos
were formerly manufactured into cloth, which was employed in wrapping the
dead body intended to be burned; the asbestos being incombustible by fire of
the ordinary kind, the ashes of the corpse were thus preserved distinct. Nap-
kins were also made of it, which were cleansed, after use, by burning instead of
washing. Wicks of lamps were also made of this material, and are now, in
some cases, used with advantage. The art of making the cloth of asbestos
seems to have been entirely lost during the middle ages. The Chevalier
Aldini has, however, by the agency of steam, succeeded in rendering the tough
and brittle fibres sufficiently pliable for weaving into cloth, and exhibited in
London gloves, caps, and other parts of dress made of asbestos, which, as being
incombustible, and a very bad conductor of heat, he proposed should be worn
by firemen.
ASPHALTUM. Called also mineral pitch, Jew's pitch, and bitumen, is a
hard black substance, resembling pitch in appearance, but having a higher
internal polish. It is found on the shores of the Dead Sea, in China, America,
and some parts of Europe. Asphaltum was anciently employed in embalming
dead bodies. The Temple of Jerusalem, and the walls of Babylon, are said to
have been built of stones cemented together with asphaltum, for which purpose
it is well adapted. It is sometimes employed in making black varnish, and is
a component of the beautiful black liquid used in printing the numbers on
watch and clock faces. The spec. grav, varies from 1.07 to 1.65. It is soluble
in oils and ether, if pure. Asphaltum was formerly employed in medicine, but
it is now seldom administered.
ARTILLERY, in its most extended sense, is applied not only to the guns,
projectiles, powder, carriages, &c. used in warfare, but to the men employed in
working them. Military engineering, however, not according with the object.
and scope of this work, the information afforded therein on the subject of artil-
lery is confined to the construction of the most improved FIRE-ARMs, GUN's,
PRoject ILEs, &c. which see under their separate heads.
ASSAY. The separation of a valuable metal from its alloy or impurities.
The art of assaying differs from that of analysis in this respect: by analysis
the various component parts of the mineral or alloy are separated, and their
I 08 ASSAY.
respective quantities estimated; by assay only the valuable metal or metals is
sought for. In the assay of gold or silver alloys, for example, the inferior
metals are dissipated, and the quantity estimated only by the loss of weight.
There are two modes by which the art of assaying is performed, and sometimes
one is employed to corroborate the other. The one is called the humid process,
by which a solution of the metals is effected by means of acids, after which those
sought for are precipitated by proper re-agents; the other is called the dry
process, and is performed by the agency of fire. In the mining districts, the
comparative value of some ores is roughly estimated by the dry process of
assaying. In London, the mode is seldom resorted to, except for the purpose of
estimating the quantity of gold or silver in an alloy. The quantity of these
metals, or of platinum, in any alloy, may be as correctly estimated by the dry,
as by the humid, process; we shall therefore describe the mode of assaying
those alloys in this article, and refer the reader to the analysis of ores (see ORE)
for the most correct mode of assaying other metallic compounds. An alloy of
gold is assayed by detaching from different parts of the article a small portion,
by a knife or a file, until the requisite number of grains for the experiment is
obtained. These being carefully weighed, are wrapped in a piece of sheet lead,
and placed in the bowl of a cupel, and exposed under a muffle to an intense
heat. The cupel is a small cubic or circular solid, with a cavity on the upper
surface to receive the metal; it is made of a very porous material ; the ashes
of burnt bones, made into a paste with water and slowly dried, are generally
employed for this purpose. When the alloy and lead are exposed to intense
heat, as before described, fusion of the whole ensues, but the lead speedily
becomes converted into a vitreous oxide or glassy fluid; this powerfully promotes
the oxidation and vitrification of any inferior metal contained in the alloy, and
when they are thus changed, they percolate through the porous cupel, and leave
only a globule of metal not oxidable by heat. This globule, therefore, will be
of gold or silver, or a compound of them, these metals, as well as platinum,
not being affected by the action of fire and air. To separate the silver from
the gold, the alloy is hammered or rolled into thin plates, and digested with
dilute nitric acid; this dissolves the silver, but does not act on the gold. When
the first solution is poured off, another portion of nitric acid is added, to effect
a perfect solution of all the silver. . The gold is now left as a porous spongy
mass, and when washed and dried, its quantity is ascertained by weighing.
If the quantity of silver in the alloy be small, the excess of gold defends it
from the action of the nitric acid; the process called quartation must therefore
be resorted to. This consists in adding three parts of silver to the mass, and
fusing them together. The silver, then, being in excess, is all separated by the
mode before described. The quantity of silver may be ascertained by pre-
cipitating it from the solution with muriate of soda. An insoluble substance,
chloride of silver, is thus formed, which, when carefully washed, dried, and
weighed, will indicate the quantity of the metal, 100 parts of the chloride con-
taining 75% of silver. In estimating the commercial value of gold and silver
articles, they are said to be so many carats fine; the carat does not denote any
specific weight, but a part. Each article is said to contain 24 carats, whatever
may be its weight; and the quantity of alloy in carats, or parts, is deducted from
the whole. Thus, if an alloy contain 4 parts of inferior metal, it is said to be
20 carats fine; if it contain 6, it is of 18 carats fine, which is the standard of
jewellery in England. In France, where every small article of gold is assayed
before it is permitted to be sold, a different mode of assay is adopted. The
trinket is rubbed on a black touchstone, formed of the black basaltes; black
flint or pottery will answer the purpose as well. The jeweller states the quan-
tity and nature of the alloy employed in the article, and the mark it makes on
the touchstone is compared with a similar mark made by a needle composed of
the same metals and the same proportions. If they correspond in appearance,
and are not differently affected by nitric acid or heat, the alloy is pronounced
to be of a similar kind to the needle. A great number of assay needles, formed
of different proportions of alloys, are necessary for this mode of assay, and long
practice and experience in the artist are indispensable. He is guided' in the
ATMOMETER. 109
operation, not merely by the appearance of the stroke on the touchstone, but
also by the comparative roughness or smoothness, dryness or greasiness, which
is observed in rubbing. The gold coin of Great Britain is 22 carats fine:
silver coin is composed of 12% silver and 1 of copper. An alloy of silver with
an inferior metal is assayed by cupellation alone, the process of quartation not
being necessary. A given portion is placed in the cupel with a sufficient
quantity of lead, and exposed under a muffle to intense heat, until the lead
and other inferior metals are vitrified and absorbed by the cupel. The workman
is guided in this operation by the appearance of the melted globule. Until the
last portions of the alloy have passed through the cupel, the mass appears to
be in a state of commotion or ebullition; but when they are absorbed, the silver
becomes quiescent, and exhibits brilliant prismatic colours.
ASTRINGENT. A substance possessing a peculiar rough austere taste.
This is remarkable in the tincture of galls, bark, the husks of walnuts, green
tea, port wine, &c. , Leguin first observed that the astringent principle might
be separated from the tincture of galls by albumen, with which it forms an in-
soluble compound. Astringents are sometimes called tannin, and are extensively
employed in tanning leather. Astringents are used in medicine to relieve
diarrhoea, and as tonics. -
ASTROSCOPE. An astronomical instrument, composed of two cones, on
whose surfaces are exhibited the stars and constellations, by means of which
they are both easily found in the heavens.
ATHANOR. A kind of furnace, which has long since fallen into disuse.
The very long and durable operations of the ancient chemists rendered it a
desirable requisite that their fires should be constantly supplied with fuel in pro-
portion to the consumption. The athanor furnace was peculiarly adapted to
this purpose. Beside the usual parts, it was provided with a hollow tower,
into which charcoal was put. The upper part of the tower, when filled, was
closely shut by a well-fitted cover, and the lower part communicated with the
fire-place of the furnace. In consequence of this disposition, the charcoal sub-
sided into the fire-place gradually, as the consumption made room for it; but
that which was contained in the tower was defended from combustion by the
exclusion of a proper supply of air. A variety of domestic stoves for burning
bituminous coal, on the same principles, but with a different object, that of
burning the smoke, have of late years been introduced and patented. See
STOVE, and GRATE.
ATMOMETER. The name given to an instrument, by its inventor, Pro-
fessor Leslie, to measure the quantity of exhalation from a humid surface in
a given time. A thin ball of porous earthenware, 2 or 3 inches in diameter,
with a small neck, has cemented to it a long and rather wide tube of glass,
bearing divisions, each of them corresponding to an internal section, equal
to a film of liquid that would cover the outer surface of the ball to the thick-
ness of his part of an inch. These divisions are ascertained by a simple calcu-
lation, and numbered downwards to the extent of 100 or 200. To the top of
this tube is fitted a brass cap, having a collar of leather, and which, after the
cavity has been filled with distilled or boiled water, is screwed tight. The out-
side of the ball being now wiped dry, the instrument is suspended out of doors
to the free action of the air. The quantity of evaporation from a wet ball is
the same as from a circle having twice the diameter of the sphere. In the
atmometer, the humidity transudes through the porous substance just as fast as
it evaporates from the external surface; and this waste is measured by the cor-
responding descent of the water in the stem. As the process goes on, a corre-
sponding portion of air is likewise imbibed by the moisture on the outside, and
being introduced into the ball, rises in a small stream to replace the water. The
rate of evaporation is nowise effected by the quality of the porous ball, but
continues the same, whether the exhaling surface appears almost dry, or glisters
with superfluous moisture. When the consumption of water is excessive, it may
be allowed to percolate gradually, without dropping, by unscrewing the cap. In
a review of Leslie's Meteorology, published in the Journal of Science, for Oct
1822, the writer recommends a vessel of porous earthenware, of a given sarface,
P
11 (3 ATTRACTION.
filled with water, to be poised at the end of a balance, and the loss of weight
which it suffers by evaporation in a given time, to be noted. A thermometer
being inserted into the mouth of the vessel, will indicate the temperature of the
evaporating mass, and would form, at the same time, a good hygrometer, on
Dr. Black's principle, that the degree of cold generated by evaporation is pro-
portional to the dryness of the air. See Leslie on Heat and Moisture; also Ure's
IDictionary.
ATTAR OF ROSES. An essential oil, obtained from roses, of great value,
and possessing wonderful odoriferous properties. Gareepon is celebrated
throughout India for the beauty and extent of its rose gardens; the rose-fields
occupy many hundred acres; the roses are cultivated for distillation, and for
making attar. The price of a sieve, or two pounds' weight, (a large quart) of
the best rose-water, is eight lenas, or a shilling. The attar is obtained after
the rose-water is made, by setting it out during the night, until sunrise, in large
open vessels, exposed to the air, and then skimming off the essential oil, which
floats on the top. To produce one rupee's weight of attar, 200,000 well-grown
roses are required. The juice, even on the spot, is extravagantly dear, a
rupee's weight being sold at the bazaar (where it is often adulterated with
sandal-wood oil) for 80 s. r., and at the English warehouse for 100 s. r. or 10l.
sterling. Mr. Mellville, who made some for himself, said he calculated that the
rent of the land and price of utensils really cost him 5l. for the above quantity.
ATTRACTION denotes the tendency which is observed in bodies to approach
and adhere to each other; it is also sometimes employed to signify the unknown
cause of this tendency. It assumes various names, according to the circum-
stances in which it acts. Thus we have the attraction of gravitation—the
attraction of electricity, or electrical attraction—the attraction of magnetism—
cohesion, and chemical affinity. The first three of these act at sensible dis-
tances, but the range of the other two is too limited to be appreciated by the
unassisted senses. -
The Attraction of Gravitation is the power that upholds the whole planetary
system, and retains bodies on the surface of our earth; its action is perceptible
at the remotest part of the solar system, and is even manifest among the
fixed stars and nebulae. The laws to which the manifestations of this power
are subject will be stated under the article on GRAVITY: at present, we shall
confine ourselves to a statement of two experiments connected with this
subject, which will clearly evince the existence of this power as inherent, not
only in the earth, as a distinct body, but in small, and even detached portions
of its surface. The first of these experiments was made by Dr. Maskeline, on
the mountain Shebralien, in Scotland. A long plumb-line, attached to a
telescope, was suspended successively on the north and south sides of the
mountain, when it was found, on each occasion, that the plumb-line did not
hang perpendicularly, but was deflected towards the mountain. The other
experiment was made by Mr. Cavendish, who, by means of a long and fine
silver wire, suspended a slender deal rod, so that it might, by twisting the wire,
vibrate freely in a horizontal plane. Small balls of lead were attached to the
ends of the deal rod, and, by means of mechanism, larger balls of that metal
were carefully brought near to the smaller ones. At each approach of the
larger balls, the small ones were sensibly attracted, made to vibrate, and finally
arrange themselves in a new position. .
Attraction of Electricity is that which occurs between two bodies, one of
which is electrified positively, and the other negatively; or one of which is
positive or negative, and the other in its natural state. It is probable, however,
that this last case is merely apparent, since every body, when brought near to
an electrized body, becomes itself electrical by induction. See ELECTRICITY.
Attraction of Magnetism is that which takes place when a loadstone or an arti-
ficial magnet is approximated to a piece of iron or steel. It also occurs when
the south pole of one magnet is made to approach the north pole of another.
Cohesive Attraction is that which subsists among the minutest particles or
atoms of a body, forming them into a solid mass. In gases, this power appears
to be wholly deficient, or at least more than counteracted by the effects of an
AUGER. 111
antagonist power—repulsion. In liquids there arc but small manifesiations of
its existence, but in solids it evinces itself in the most decided and conspicuous
imanner. The intensity of the cohesive force varies in different bodies, whether
solid or liquid, a circumstance which renders a knowledge of its laws of the
greatest importance to mechanics, engineers, and other practical men. For the
elucidation of these laws, and the facts on which they are founded, see CoHEsion.
Chemical Attraction is that which connects the particles of different bodies,
and forms them into compound substances. Thus, the power that unites the
particles of a mass of copper is called cohesion; but that which causes the union
of copper with sulphuric acid, or nitric acid, so as to form sulphate or nitrate of
copper, is denominated chemical attraction, affinity, elective attraction, or attrac-
tion of composition. Hence we see that chemical attraction and cohesion co-
exist in the same body. Thus, in the sulphate of copper, one particle of sulphate
of copper is connected with another particle by cohesion; while, at the same
time, the particles of sulphuric acid are connected with those of copper by
chemical affinity. See CHEMISTRY.
AUGER. The name of a very efficient instrument, extensively used by car-
penters, and other mechanics, for boring holes in wood. There are several
varieties adapted to their peculiar offices, or to the prejudices of workmen. The
oldest, or common auger, has a long iron shaft, with a large cross handle at
right angles to it, at the top, for enabling the workman to apply both his hands
with a considerable leverage, in turning round the shaft, into which is welded a
semi-cylindrical piece of steel, from 3 to 6 inches in length, which varies with
the size or diameter of the hole made by the instrument; the extremity of this
piece is furnished with a sharp tooth, and a cutting edge, which is a small
portion of a spiral, and inclined so as to cut as a chisel, the edge operating upon
a radical line proceeding from the centre of the hole; and, as it is being con-
stantly turned in a circular direction, the chips of wood are turned out in spiral
pieces, and are received into the semi-cylinder above, which has usually one of
its longitudinal edges a little sharp to keep the sides of the perforator clean. The
upper portion of the shaft is made smaller than the lower, or steel part, for facili-
tating the escape of the chips, and to enable the instrument to pass the bore freely.
Another instrument, differing from the foregoing, is provided at its extremity
with a conical screw, like a gimlet, for piercing the wood the more readily and
truly. We have, indeed, frequently noticed in well-made augers of this kind,
that no pushing, or rectilineal force whatever is required, the screw keeping
them always up to their work.
In a third instrument, chiefly used by shipwrights, that portion of steel, al-
ready described, as of a semi-cylindrical form in the common auger, is altogether
in this made of a spiral figure, and is found to facilitate the boring materially,
besides preventing all liability of the chips becoming jammed or clogged in the
tool, which pass freely through the spiral channels, and are discharged exter-
mally as the perforation is continued.
A patent for an improvement upon the last-mentioned auger was taken out
about ten years ago, by Dr. Church, of Birmingham; but the originality of his
invention has been the subject of dispute. In the specification of the patent,
the principle of the inventor is stated to consist in forming an instrument of a
helical figure, by winding a bar of steel of a “mirtilinear trapezoid” shape,
round a cylindrical mandrel, by which a circular hole is formed throughout
its length, for the insertion of a movable central guide-pin ; the upper end of
this central pin is screwed into the shank of the auger, and the lower, or
working part, is furnished with a wood screw; the office of the latter is to draw
the auger into the wood as it is turned, the cutting edges on the helical part at
the same time clearing the wood as this auger deepens in the perforation. In
grinding and sharpening the edges of the auger, the central pin is, of course,
removed for the purpose; and it is obvious that the edges may be ground and
sharpened as long as any of the spiral steel bar remains, which renders the
instrument extremely valuable, as one, with proper care, may be made to last
a man's life-time. This auger, besides, far surpasses all others by the rapidity
and facility of its operation.
112 AUGER.
Auger for making square holes.—It appears that endeavours to supersede the
tedious and somewhat difficult process of truly forming square and other shaped
holes, varying from the circular, by means of mortice-chisels, were made both
in this country, and in America, at about the same period of time. A machine
for this purpose, invented by Mr. A. Branch, of New York, was described in
the Franklin Journal of Philadelphia, in the year 1826. It was stated to con-
sist of an auger, formed like the American screw auger, with the twisted part
inclosed in a case or socket, extending from the upper part of the twist to the
cutting edge, allowing the small entering screw to project beyond it. The ex-
ternal form of the socket is either square, or otherwise, according to the
intended shape of the hole to be bored, a large portion of its sides being cut
away to allow the chips to escape. The lower end of the socket is of steel, with
a sharp cutting edge, bevelled towards the inside. The cutting-edges are not
allowed to terminate in right lines, but are made concave, so as to admit the
angular points to enter the wood first, this causing it to cut with greater ease,
and more smoothly than it otherwise would. The upper part of the socket
forms a collar, which works freely on the shank of the auger, just above the
twisted part, and is retained in its place by a pin and other appendages. When
a longitudinal hole, or mortice, is wanted, two or more augers are placed side
by side, furnished with their appropriate sockets, and retained in their places
by obvious contrivances.” The same journal stated that it was very efficient in
its operation, boring a square hole with well defined angles, with nearly the
same rapidity as a round one of the same diameter, and forming it with a
degree of truth unattainable by the ordinary methods. Upon the publication of
Mr. Branch's invention in this country, the editor was invited by Mr. Thomas
Hancock, of Goswell-Street Road, to see, in his manufactory, a similar machine,
constructed by him several years previous; and having proved its efficacy by
boring a considerable number of square holes with great facility, and finding
that the angles were perfect, and the holes clean, and exactly uniform through-
out, we were induced to make a precise drawing of it, a representation of
which, on a scale of one-third (lineal measure) of the original, is given in the
subjoined engraving. At a a, Fig. 1, is a strong iron frame or support, fixed
by screw-bits b b to the work-bench c ; d is an octagonal iron socket, containing
a brass bush, tapped to receive the vertical screw e e ; to this screw is affixed,
by a circular tenon and mortice, the square perforating instrument f, which
accurately fits and slides up and down through a rectangular hole, in a guide of
brass g, when the screw e is turned by the cross handle at top; so that the
square incision is made by direct pressure downwards, at the same time that
the revolving centre-bit m cuts out a completely round hole, the chips rising up
and passing out at the two open sides of the square cutter; h represents a piece
of wood in the act of being bored, the dotted lines showing the depth to which
the perforation has reached; a small piece of wood i is placed underneath, to
prevent injury to the cutting-tool, by coming in contact with the cross iron
plate k ; the bolts b b passing through i as well as k, secure both firmly to the
bench c. Fig. 2 exhibits the cutting part of the instrument, separately, on an
enlarged scale, with the lowermost portion in section; the tenon i is inserted
into a cavity in the screw e, Fig. 1, and made fast by a cross pin, which goes
through both; by this arrangement the instruments can be readily exchanged
for others of different dimensions; the lower extremity of this revolving piece
is formed into a centre-bit m, which, owing to the collars n n, cannot ascend
or descend without the square instrument, which accurately cuts out the angles
beyond the range of the circular incision made by the former. The square
cutting-tool is made of a bar of steel, with a hole drilled out of the solid, in the
manner shown by the end view, Fig. 3, and the edges are then formed by filing
and grinding them to the bevels, or angles, shown in section by Fig. 2. Fig. 4
represents a similar view of the end of the instrument, but with the centre-bit
in its place. It will be readily perceived that a square tool, by repeating the
incisions side by side, close together, may be made to produce a cavity of the
figure of any rectangular parallelogram of any length or breadth, larger than
the instrument employed. The same effect may likewise be produced by a
AUG ER. 1 13
single operation, by arranging a series of centre bits or circular cutters, side by
side, with toothed wheels at their upper extremities or axes, giving into each
other, which will cause them all to bore simultaneously ; a single external rec.
tilineal cutter, embracing all the centre bits, would then suffice for the purpose.
In like manner, any acute or obtuse-angled figure, any polygon, or any figure
with curved sides, might be made of any size whatever. By the construction
of the machine described, it will be perceived that it is necessary, in changing
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the tool, to change also the guide-piece through which it slides. The screwing
and unscrewing of the guides may, however, be avoided, by having tenons in
the latter of an uniform size, to fit in a mortice in the upright iron frame; and
in manufactories where a great variety of mortices have to be made, we would
suggest another mode, in which the trouble of changing the guides would be
still less: it is to have a guide wheel turning horizontally upon the upright bar
a as its axis; on the circumference of the wheel should be made a series of
apertures, corresponding with the form of the tools and of the mortices required.
By this arrangement, indeed, most of the tools might be left in the guide-wheel,

&
114 AUTOMATON.
ready to bring any one of them into action under the screw, by just turning the
wheel round. In those branches of business wherein a great number of mor-
tices are required of one size, a machine of the kind described will be most
valuable; and as it requires no skill in the operator, a boy, or a mere labourer,
will perform the operation as well as the most experienced workman. Chair
makers might adapt a machine on this principle to their work with important
advantages; wheelwrights, also, for morticing out their naves. In the large
workshops of carpenters, an instrument of the kind described would forward a
great deal of work in framing, as it might easily be so modified as to perform
the office also of a cramp to draw the jointed parts of the work into close con-
tact. It is to be observed, that Mr. Branch's instrument is the same in principle
as Mr. Hancock's, but that it will require some modifications to render it as
efficient an instrument.
AURUM MUSIVUM, or Mosaicum, is a combination of tin and sulphur,
having the appearance of bright gold in powder. It is used by japanners, and
for varnished works, as snuff-boxes, tea-trays, &c., also to statue and plaster
figures. The usual process of preparing it is as follows: amalgate 12 parts of
the purest tin with 3 parts of mercury; the amalgam is then triturated in a
stone mortar with 7 parts of the flour of sulphur, and 3 parts of muriate of
ammonia. The mixture is next put into a matrass, and the whole exposed to a
gentle sand heat, until no more white fumes arise. After this, the heat is
somewhat raised, and cinnabar sublimes, together with some oxygenated muriate
of tin, while at the same time the remaining tin and sulphur unite, forming the
aurum musivum, exhibiting a golden yellow, and flaky scaly matter of a metallic
lustre. The principal point to be attended to is the regulation of the fire; for
if the heat be too great, the aurum musivum fuses to a dark-coloured sulphuret
of tin. The process of the Marquis de Bouillon, as described by Chaptal, differs
from the foregoing in the proportions; and the experiments of the latter chemist
are also worthy of notice. The marquis's process consisted in amalgamating
8 oz. of tin with 8 oz. of mercury, and mixing with this 6 oz. of sulphur, and
4 oz. of muriate of ammonia. This mixture is to be exposed for three hours to
a sand heat, sufficient to render the bottom of the matrass obscurely red hot.
Chaptal, however, found that if the matrass containing the mixture were exposed
to a naked fire and violently heated, the mixture took fire, and a sublimate was
formed in the neck of the matrass, consisting of the most beautiful aurum
musivum in large hexagonal plates. Bergman mentions a native aurum musivum
from Siberia, consisting of tin, sulphur, and a small proportion of copper.
According to Dr. John Davy, the aurum mosaicum, or mosaic gold, consisted
of 100 tin, and 56.25 sulphur. Berzelius makes the proportions 100 tin, and
52.3 sulphur. The mean of those results, viz. 100 tin +54.2 sulphur, may
therefore be regarded as the correct proportions. A few years ago a patent was
taken out by Messrs. Parker and Hamilton, for an alloy of copper and zinc, which
they termed the true mosaic gold. The specification directs that equal quantities
of copper and zinc are to be melted at the lowest temperature at which the
former will fuse, when they are to be well stirred and mixed together; small
quantities of zinc are then added by degrees, until the alloy assumes the desired
colour. It is essential that the heat should be as low as possible, to prevent the
rapid evaporation of the zinc. The alloy first assumes a yellow colour; the
addition of more zinc turns it first to a purplish tint, which ultimately becomes
perfectly white, which is the colour it should have when in a state of fusion. It
may then be cast into ingots for use; but it is preferable to cast the alloy, in
the first instance, into the forms required, as a portion of the zinc flies off on
remelting.
AUTOMATON. In the strict sense of the word, a piece of mechanism in
which the effects are produced by some inanimate force contained within it;
the word is, however, more commonly used to signify a piece of mechanism
made to resemble some animal, whose motions it imitates by means of internal
machinery, which being concealed from the spectator, gives it an apparent
power of acting by volition. Numerous descriptions of automata of this class
are to be found in the writings of various authors, amongst the most admirable
AUTOMATON. 115
of which may be ranked the automaton flute-player of M. Vaucauson, of
which the ingenious inventor published a very full description. It is to be
regretted that this description was not, at least as far as we can find, accom-
panied by drawings, which were desirable for the better elucidation of the sub-
ject. We are, on this account, induced to relinquish our desire to give place to
it here, and must content ourselves merely by observing, that the figure was of
the natural size, and that the different notes were produced by a current of air,
urged by bellows contained within the pedestal on which it was placed, and
passing through the lips into a flute, the holes of which were stopped by the
motion of the fingers of the figure, whose tongue and lips were likewise movable,
and aided in the modulation of the sounds. The same artist also subsequently
produced another figure, representing a Provençal shepherd playing on a pipe,
and beating a tabor, which he describes as attended with greater difficulty in the
execution than the preceding one. But of the many inventions of this description,
none have attained such celebrity as the automaton chess player of Baron de
Kempelen, of Vienna. It was a figure, representing a Turk seated at a square
table, or chest, the top of which formed the chess-board, on which the automaton
made the various movements. It was exhibited in most of the leading cities of
Europe, but the principles of its construction were never disclosed; nor, although
it had been frequently asserted by many persons that the whole was a trick, and
that the motions were produced by an individual concealed within the figure,
various ways in which this might be effected being pointed out, was any exami-
nation permitted sufficiently strict to lead to the exposure of the deception, if
any was practised. The exhibiter affected great apparent openness in displaying
the various machinery of wheel-work and levers which the interior certainly
did contain; but this might have been placed there as much for the purpose of
aiding in a deception, as for any useful object. When the writer saw the figure,
during its exhibition in the Haymarket, in 1816, it was shown in a manner which
precluded any close examination; the spectators were ranged upon a series of
rising benches, at a considerable distance from the figure; the attendant first
opened several doors in the machine in succession, to show that no person was
concealed within it; the doors being then closed, the machine was wheeled
round the room, that it might be seen there was no connexion with the floor.
The game then commenced; the person who played against the figure was
seated at a small table, railed off at some distance from it, and had before him
a chess-board, with the full complement of black and white chess-men; the
chess-board before the figure was furnished in a similar manner. When the
player made a move, the attendant made a similar move upon the chess-board
of the automaton; and when the latter moved, the attendant repeated the move
upon the chess-board of the person playing. Without pretending to explain the
manner in which the motions of the figure were produced, we think that from
the very nature of the thing we may assert that they were not effected by the
mechanism contained within it, for we consider mere machinery utterly incom-
petent to produce the requisite effects. We shall proceed to state the grounds
on which we have come to this conclusion. Any variety of movements which
are required to follow each other in a certain order of succession, may doubtless
be produced by mechanism, as, for instance, the striking parts of a clock, or,
more especially, in the calculating machine of Mr. Babbage; nor is it necessary
that the succession be in any regular order, provided, as in the kaleidoscope,
the results may be altogether arbitrary, or the effect of accidental combinations;
but the moves at chess, although they follow no regular order of succession,
for they may be infinitely varied, may yet not be made indiscriminately, but
depend upon circumstances beyond the control of the machine, such, for
instance, as the moves of the antagonist, or the number and position of the
pieces on the board. From these considerations, we conclude either that the
motions are governed by some person from without, by means of some inge-
niously contrived and concealed mechanism, or by some person secreted within
the machine. The author of a pamphlet on the subject, published in 1821,
maintains the latter supposition to be the fact; and by the aid of several diagrams.
shows that not merely a dwarf, as was at one time supposed, but even an ordi-
116 AXI, E-TREES.
nary-sized man, might be concealed; and this opinion is further corroborated by
the proprietor refusing to exhibit the figure in action, with the several doors of
the machine open, when requested to do so by a scientific gentleman, whose
object was to satisfy himself and some friends that the movements were really
roduced by machinery.
AXE. A heavy steeled instrument, employed for cutting down trees, and
by carpenters and other mechanics for cutting large masses of wood, when
attention to much exactness is unnecessary, or the saw cannot be conveniently
used. It consists of a broad blade of iron, with a loop, or eye, for the recep-
tion of a long wooden handle, which passes through it at right angles. The
cutting-edge is steeled to about an inch in breadth, and to the back of the eye,
in some kinds, is welded a solid lump of steel, called the poll, which serves the
carpenter as a very efficient heavy hammer for driving spikes, forcing up large
tenons, mortices, &c. The form of axes are very various, being adapted to
peculiar trades, and accommodated to provincial prejudices. The most perfect
instruments we have seen of this kind, are the productions of several tool-
smiths, distributed over the county of Kent. One we recollect at Seal, another
at Seven Oaks. We have thought it proper to mention this fact, as the article
alluded to has a very decided superiority over those made in our great manu-
facturing towns. The smaller kind of axes, weighing under 2 lbs. each, are
denominated hatchets,
AVIARIES. A place appropriated to the feeding and rearing of birds, suf-
ficiently extensive to allow them scope for flight. The inclosure is usually made
of net-work, duly supported, but preferably of wire-work. The interior is
sometimes provided with trees, and other objects of nature; and the floor
covered with turf, to avoid the appearance of dirt.
AXIOM. A self-evident truth, or one that neither requires nor admits of a
proof, because it cannot be made plainer by demonstration; as, for instance, “a
whole is greater than a part.”
AXIS, in Geometry, is the straight line about which a plane figure revolves,
so as to produce or generate a solid; or it is a straight line drawn from the
vertex of a figure to the middle of the base. The axis of a circle or sphere is
a straight line passing through the centre, and terminating at the circumference
on the opposite sides. The axis of a cone is the line from the vertex to the
centre of the base. The axis of a cylinder is the line from the centre of the
one end to that of the other. Transverse awis, in the ellipse and hyperbola, is
the diameter passing through the two foci, and the two principal vertices of the
figure. In the hyperbola it is the shortest diameter, but in the ellipse it is the
longest. Conjugate aris, in the ellipse and hyperbola, is the diameter passing
through the centre, and perpendicular to the transverse axis. It is the shortest
of all the conjugate diameters.
AXIS, in Mechanics, is a line about which a body may turn : by workmen,
the term axis is generally considered to imply a cylindrical bar, around or upon
which a wheel, or other body, rotates.
AXIS, in Peritrochio, a pedantic name which has been given to one of the
mechanical powers, commonly called the wheel and axle.
AXLE-TREE. The pivot, or centre, upon which a carriage wheel turns. They
were formerly made of wood, and, we believe, are to this day, in some parts of
the country, but are now generally constructed of iron. Numerous improve-
ments have, of late years, been introduced in their construction, some of which
we shall notice, after a few words upon their more ancient construction. One
very old plan was to fix the axle immovably into the naves of both wheels, the
axle revolving in bearings attached to the carriage; by this means the nave
was less weakened, and the wheels had less play, than if the axle-tree was fixed
to the carriage, and worked in a box in the nave, but were inconvenient in
turning, as both wheels revolved with the same speed; the axle-trees were,
therefore, attached to the carriage, and each wheel revolved separately upon its
axle, by which means, in turning short, the inner wheel could remain sta-
tionary, and serve as the centre of motion to the carriage. Axles were
originally made straight, their arms lying in the same horizontal plane, and
AXLE-TREES. 1 ! 7
the wheels, of course, perpendicular to them; but as carriages came more gene-
raily into use, more room was required; and the roads being narrow and bad,
and the wheels being, therefore, required to keep in the beaten track, recourse
was had to splaying the wheels, by bending the axles downwards, by which
means the upper part of the rims of the wheels were further apart than the
lower; and this method continues in general use to this day, although the im-
proved state of the roads no longer requires it, and the draft is made heavier,
and the roads more quickly destroyed by it. The objects chiefly aimed at in
the various improvements in axle-trees, is to diminish the friction by decreasing
the amount of rubbing surface, and by carefully excluding dirt from the boxes;
in keeping them well oiled, and to attach the wheel so securely as to avoid
the fatal consequences arising from the linch pin falling out. We shall now
roceed to describe two constructions of axle-trees, invented by Mr. Mason, of
º Street, Cavendish Square; the first adapted to what are commonly
called Collinge's, or patent axles; and the second, to the description of axles
called mail-coach axles. The first construction is shown in Figs. 1, 2, 3, and 4.
*
*
g
e
S. ºº *grºw *-**
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º gººsºº"::::::::::::::::::::::::::
Zºº sº. º. ºr’ :::::::::::::
**.*.*: *::::::::::::::::::::::::::::::::::::::::::::
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- vºw.www.y E. : *
*Avvy AA
º a
63. {{
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r :
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Fig. 1 represents a perspective view of the axle, with its principal append-
ages arranged in a line to show the mode of their application. Fig. 4 repre-
sents a longitudinal section of the axle-tree, with its several appendages screwed
up into their respective places, and lying inclosed in the box peculiarly con-
structed for that purpose. Figs. 3 and 4 give sections of certain parts of the
axle-tree and box, hereafter to be described. The like letters refer to similar
parts in each figure. a a, the main part of the axle-tree; b, a fixed shoulder;
c, a movable shoulder formed upon a metal collet, and rendered capable of
being slided backwards and forwards, but not of turning round. This collet is
adjusted and retained in any required situation, as will be presently shown ; d
is a screw formed upon the outer end of the axle-tree; e is a nut, hexagonal on
the outside, and screwed in the inside to fit d. Around the inside of the hex-
agonal nut are cut longitudinal, and at equal distances, six semicircular
grooves (as partly shown in Fig. 1), but more distinctly seen in the section
Fig. 2; the screw d has, likewise, two similar grooves cut into its thread, and
so placed with regard to each other, that when one groove corresponds with
one of the grooves in the nut, the other groove shall be midway between two
Q










1 18 AXLE-TREES.
other grooves in the nut; and, in order to fix this nut in the required position,
a cylindrical pin, which is rivetted to the hexagonal plate f is inserted into one
of the holes formed by the union of a groove in the nut with a groove on the
axle, which entirely prevents any rotation of the nut so long as the pin remains
in the hole; and there being two grooves in the axle, and six in the nut, the
position of the nut may be regulated to # of a turn, equal to # of an inch,
if the screw has 10 threads per inch. To prevent this pin coming out, a collar
of leather g is first put on the long hexagonal-headed screw h, when the latter
being screwed into the internal screw of the axle-tree (seen at Figs. 2 and 4), the
whole is thus made fast. Having thus described the construction of the axle-
tree, it remains for us to explain the construction of the box, which we have put
in section in its proper place, around the axle-tree in Fig. 4. k h k ſº show the
cylindrical parts of the box, with a cap l l screwed on its outer extremity, which
serves to contain oil for those parts of the axle-tree which are contiguous. o o
are long grooves also for oil; two of these are brought into view in the longi-
tudinal section, Fig. 4; but there are four of them, as may be seen in the trans-
verse section at Fig. 3, which section is made where the dotted line divides
Fig. 4. p p is another reservoir for oil. The whole of the arrangements in
this invention appear to us excellent. The quantity of oil contained in the
reservoirs, and which is constantly circulating round the axle, is greater than in
any other wheel-box that we recollect, and must greatly reduce the friction.
The ease and safety with which the wheel may be let out when travelling on
bad roads, is another great advantage, and which we believe to be peculiar to
this axle, whilst the method of securing the wheel upon the axle seems to leave
nothing to be desired on that head. This last part of the invention may be
also usefully employed in various parts of machinery, as where wheels run upon
studs, or pivots, &c. The figure beneath represents Mr. Mason's improved mail
Pº zºº
axles, although some parts of the invention are applicable to the patent axles.
a is the box cap, which constitutes at the same time an oil cup with a conical
end c, which fits into the conical part g of the axle f; when that is fitted into
the box e and the cup screwed into d, the oil then flows through an aperture
in the end of the cup c into the hollow part of the axle, and passes out to
the box at an aperture h, supplying the long reservoirs in the interior of the
box. There is, likewise, a very small groove cut longitudinally on the axle,
extending both ways from h, so that the oil may be readily distributed over all
the bearing parts. This lubricating arrangement is, evidently, applicable to
both kinds of axles, but the other part of the contrivance, which has for its
object the better security of the wheel, and the prevention of end-play, so as
not to allow the escape of oil from the box, nor the admission of dust, or other
impurities into it, applies exclusively to the mail axles, or those which are kept
in the box by means of screws at its inner end. Three wrought-iron screws
are cast into three legs on the box, two of which are shown in the figure at
n n. When the axle is introduced into the box, the conical part i fits the
conical part j, and tends to preserve the leather collar between i and k, while
the loose plate m fits upon, and is firmly secured by, the screws m n to the end
of the box, and thus the box is kept in its place by the collar k, which works in
the recess l, and the wheel is prevented from coming off by the plate m m.

AXLE-TREES. 1 9
Formerly, this plate was fastened by short screw-bolts passing through it and
the legs of the box, a method which was found defective on account of their
liability to shake loose by the constant jarring of the coach. To remedy this,
and to facilitate the removal of the wheel when desirable to take it off, the back
plate was fastened by long bolts passing through the nave and screwed on the
outside; but this, too, was found to be objectionable, on account of the injury
caused to the nave by the bolt holes, and their occasional removal, when
the wheel required taking off; and to remedy these defects, is the object
of the invention which we have been describing. An objection to the
present mode of locking the fore wheels of four-wheeled carriages from the
centre, is, that in sharp turns, the fore-wheels are brought so nearly in a line
with the perch, that the coach has little better than three points of support, and
is, therefore, very liable to be overturned. Another inconvenience arising from
this method is, that it requires the fore-wheels to be made much smaller than
the hind ones, which greatly increases the draft, and has, at the same time, an
inelegant appearance. These objections are obviated by a construction, for
which Mr. Ackerman took out a patent in 1816, the principle of which is as
follows: The fore axle-tree of the carriage does not turn, but is fixed to the
perch in the same manner as the hind one; each of the fore wheels revolve
upon one end of a short arm, the other extremity of which is turned up at a right
angle, and turns in a hinge joint at each extremity of the fixed axle-tree; from
the back of each of the short axles, a lever projects, and the coach-pole being
carried back beyond the pin in the fixed axle-tree, an iron bar connects the:
extremities of the two levers, and of the coach-pole, so that when the coach-
pole turns upon its fulcrum, the short axles turn upon their upright arms as
§ºliº t *.
#########|lity.
#1.”
w #.
. . . . . ;-
|
centres, and if the length of the connecting bar be equal to the distance between
the vertical arms of the axles, the two wheels will always stand parallel to each
other; but by varying the length of the connecting bar, the inner wheel, in





120 AXLE-'H'REES.
turning, may be made to perform a shorter curve than the outer one. The cut
represents one of these arms, Fig. 1 being a front view, and Fig. 2 a side view ;
a is a portion of the fixed axle-tree; b the horizontal arm upon which the wheel
revolves; c the vertical arm; d the lever; e connecting bar. In the diagram,
Fig. 3, the dotted lines represent the position of the fore wheels when locked to the
utmost extent; and the other lines, their position in the same circumstances, with
axles on Mr. Ackerman's plan, from which it will be seen that the latter afford a
much wider base to the carriage than the former; the wheels may also be made
of nearly the same diameter as the hind wheels, without hanging the body of
the carriage higher. A B is the line of the perch. Patents for axle-trees upon
the same principle have since been taken out by Miss Knowles, and by Mr.
Mason, varying slightly in the details. There have been many plans proposed
for diminishing the friction at the axle by means of anti-friction rollers; but,
from the experiments made upon rail-roads, of the resistance of running wheels
thereon, as compared with those on common roads, it appears, the amount of
friction of the axes of wheels made in the common way, was so extremely
trifling in comparison with the resistance at the peripheries, that it became
absolutely impossible to gain any practical advantage of moment by such a re-
duction of the axles as they are susceptible of. It should be borne in mind, that
the weight of the carriage must be supported on some of the rubbing, or re-
volving, parts; and these parts being already, comparatively, very small, their
surfaces cannot be much reduced without impairing the requisite strength. By
anti-friction rollers, we only transfer the friction, without materially lessening
it; whilst we incur complexity, increased expense, and greater liability to de-
rangement. For these reasons, we shall notice only one out of the many con-
trivances on this subject; it is the invention of Mr. Spong, and is selected as
being the simplest in construction, a e is the revolving axle-tree made square
|
at a for inserting into the nave of the wheel, to which it is made fast, by means
of the nut b screwing it close up to the shoulder c. The circular part of the
axle revolves in two bearings; one in plummer blocks at d, regulated by screws
at l; the other at e, in a solid piece projecting from the axle-tree f. The thick
end of the axle at o, carries an anti-friction roller k, which turns on a short pivot,
or axis, at # (shown by white dots). Oil is applied to the bearings and axis, by
means of perforations at h h, which are closed by screw stoppers.
From an account of some experiments made by Mr. H. R. Palmer, now
engineer to the London Dock Company, it would appear that the forms of the
cavities, or interstices, through which the lubricating matter is applied to the
axes of wheels, is of considerable importance. During a succession of
experiments occasionally for many months, he invariably perceived that when
fresh oil was applied to the axles of the carriage, the resistance was increased,
and it required the ordinary motion of the carriage for several days to restore
the resistance to its usual standard. No other presumption occurred to account
for this fact, than the possibility of the oil being better’ adapted for its office
after being some time exposed to use. It was suggested to him that the oil
became thickened, or less fluid, after exposure to the air, and was therefore
better able to resist the contact of surfaces. In order to prove this, he thick-
ened some oil artificially, by the admixture of a small quantity of bees'-wax,
but the appearances were the same as before. It then occurred to him, that
there was not sufficient play, or difference of diameters, between the axle and





AZIMUTH. 121
the nave in which it worked; he therefore had the axles slightly reduced. On
again measuring the resistance, he found circumstances as before, but differing
in amount, the resistance being slightly increased. He was by this time con:
vinced that the quantity, rather than quality, of oil, occasioned the appear-
ances; to prove which, the axles were made perfectly clean, and then simply
moistened with oil by the finger, previous to inserting them in the wheel. In
this state the resistance was again measured, and found to be similar to the
standard usually observed after the carriage had been some days in motion, as
before described. It being, then, proved that the quantity of oil occasioned the
difference of resistance, the following solution of the manner in which the addi-
tional quantity could produce such an effect, appeared reasonable. Let A B C D,
1°9. 1, represent the circle of the hole in the nave of the wheel, and E C the
Fig. 1. Fig. 2.
A A
B D B D
O


section of the axle. The circle E C touches A B C D only in the point C. A
very acute angular space then remains between A E and C on either side of
EC. If that space be filled with oil, the oil may be considered as a wedge, and
if the outer circle be set in motion, that wedge will endeavour to pass the point
Q: , But it cannot pass in its present form without raising the circle E C.; but
E C having the weight of the carriage upon it, would resist its passage. Now
this continual and unsuccessful endeavour to pass the point C will occasion an
impediment to the motion. To put this solution to the test, the axles were
formed as in Fig. 2. A B C D is the hole in the nave as before, and E FC G
the section of the axle. The lower semicircle of the axle here corresponds with,
or is parallel to, the outer circle, but no further, because if it corresponded
throughout the circle, the awle would be liable to jamb, as other experiments have
proved. The coincidence then ceases abruptly, as at B F.G D, and the space
above which contains the oil is not angular, but the quantity of oil which is to
pass toward the lower semicircle is determined at B or D. On measuring the
resistance with the axle thus formed, he found it not increased by any quantity
of oil that might be inserted; but by dispensing with the angular space, and
consequent wedge-like action of the oil, the resistance was one-tenth less than the
Jormer standard. In cases where the difference of diameters is considerable, he
does not apprehend the obstruction from the quantity of oil would be of conse.
quence; but it is desirable to make the bearing surfaces nearly to correspond,
to obtain a greater width of touching surface, and the more perfectly to govern
the motion. The form of axle just described is, in fact, the converse of a well-
made plummer block, used in machinery.
AZIMUTH, in Astronomy, is an arch of the horizon intercepted between the
meridian of a place, and the azimuth, or vertical circle, passing through the
given object; or it is the angle formed at the zenith by the meridian and ver-
tical circle. The azimuth of the sun, or a star, at the time of the equinox, is
found by the following proportion. As the radius is to the tangent of the lati-
tude of the place of observation, so is the tangent of the sun's, or star's,
altitude, to the cosine of the azimuth from the south.
AZIMUTH, Magnetic, is an arch of the horizon included between the mag-
netic meridian, and a vertical circle passing through the object. It differs from
the true azimuth, on account of the variation of the magnetic needle. The
magnetic azimuth may be determined by observations with the azimuth com-
pass, and the true azimuth calculated therefrom.
122 BALANCE.
AZOTE, or NITRog EN. The phlogisticated air of Dr. Priestley. It contains
four-fifths of atmospheric air, and one-fifth of oxygen. See CHEMISTRY, and
NITRogen GAs.
AZURE. The blue colour of the sky, and the name given to a celebrated
Egyptian pigment, which has preserved its brilliancy of tint for upwards of
seventeen hundred years. The late Sir Humphrey Davy, who experimented
on the constitution of this substance, found that it might be easily and cheaply
imitated. Thus take 15 parts of the carbonate of soda, 20 of powdered opaque
flints, and 3 of copper filings; strongly heat them together for two hours, when
a substance will be produced, which, when powdered, affords a fine deep-coloured
blue pigment, closely resembling the Egyptian azure.
AZURF-STONE, or LAPIs-LAzul.1, is a massive mineral, of a fine azure
blue colour. Lustre, glistening. Fine grained, even fracture. Scratches glass,
but scarcely strikes fire with steel. Opaque, or translucent, on the very edges.
Easily broken. Spec. grav. 2.85. It consists, according to Mes. Clement and
Desormes, of 34 silicia, 33 alumina, 3 sulphur, 22 soda, loss 8,-100 parts.
The finest specimens are brought from Persia and China. It is from these
stones that the beautiful unchangeable blue pigment, ultramarine, is prepared.
The stones are first made red hot, then thrown into water to cool them sud-
denly, which enables them to be easily pulverized. The fragments are then re-
duced to a very fine powder in a mortar, and intimately combined with a
varnish composed of resin, bees-wax, and linseed oil. It is then of the con-
sistence of paste, and is put into a linen cloth, and repeatedly kneaded with hot
water. The first water is thrown away, the second gives a blue tint of the first
quality, and the third yields one of less value. This processis founded on the pro-
perty which the colouring matter of the lapis-lazuli has of adhering less firmly
to the resinous cement, than the other matter with which it is combined
B.
BAKING, in its true sense, implies the process of applying a dry or scorching
heat to any substance in a close vessel or chamber; but the term is generally
understood to mean the art of preparing bread, for which see BREAD, Oven, &c.
BALANCE. A simple machine, in which the lever is employed to determine
the equality or difference of two given weights. Balances are of various kinds,
differing in their form, and in the perfection of their construction, according to
the nature of the objects for which they are employed. The common balance
or scales are well known to consist of a lever

or beam a b, turning on its axis in a ver- Q-Sº)
tical plane, and having two dishes or scale-
pans d e suspended at its two ends. The
distances between the centre of the beam
and the extremities a and b are made as
nearly equal as possible : hence it is clear,
from the nature of the lever, that the
weights placed in the two scales will be
º to each other when the beam rests in
a horizontal position. . Although, theoreti-
cally speaking, the balance is exceedingly
simple, consisting merely of a right line
turning on its centre, yet in practice it 2—-- ~~~~~
becomes a matter of considerable difficulty --------T-T—i... ...
to approximate its construction to that perfection which theory points out, and
which the nicer operations of philosophical research demand. Although it is
not necessary on all occasions to use a balance capable of detecting differences
in weight equivalent to the ºn of a grain, yet the more perfect our model is,
and the nearer we approach to it, the greater chance there is of obtaining the
object of our search, viz. an exact indication of the weight of any given sub-
stance. In the most perfect balances, one of which is represented in the annexed
engraving, the beam J. L is a bar of tempered steel, so strong as not sensibly
BALANCE. 123
tº bend with the weights usually placed in it. If G is the centre of gravity of
the beam, the arus G L G L should be of precisely the same length. At the
extremities, silk cords of the same length and weight support the scale-pans A A,
which are also equal. . That the slightest motion of the beam may be distin-
guished, an index SC is attached to the beam exactly perpendicular to it, and
in the same plane with the centre of gravity. The whole is sustained on an
gº º :Nº ºth
== &== ==ºffs ###:===
º:
EEEEEEEEEEEEE:: d
#. S-S
S H_| Stºs
axis perpendicular to the beam at C; and in order that the line around which
the beam turns may not change its place, and thus vary the lengths of the arms,
the axis is formed below into a sharp knife edge of hardened steel, and moves
on planes of polished crystal, agate, or other hard substance. Now if a perfect
equality were established between the parts of the balance on each side the
Centre G, an equilibrium would naturally occur when the beam L. L' was in a
horizontal position; for the centre of gravity of the whole would then be in the
same vertical line as the point C.; hence if weights were placed in the scale,
and the beam retained its horizontal position, we might infer their equality.
But an experiment of this kind may be possible or not, according to the posi-
tion in the vertical line of the points C and G. If the centre of gravity G
coincided with the centre of motion C, the beam would rest in any position
into which it might be thrown. Or if the centre G were above the centre C,
the beam would remain horizontal when placed so, but its equilibrium would
be unstable, and the least additional weight to either side would cause that side
to descend indefinitely. But if the centre of gravity be below the centre of
support, then, if the horizontality of the beam be deranged, it will be recovered
after a succession of oscillations of continually diminishing amplitude. The
delicacy, or stability, of the beam, will depend, in a great measure, on the dis-
tance between these two points. Thus, if G be much below C, a considerable
weight will be required to turn the beam, but it will soon regain its state of
rest. On the other hand, if the point G be only a short distance below C, a
slight additional weight will cause the arm to descend, but it will be longer. II]
regaining its quiescent position. The sensibility is increased by lengthening
the arms, diminishing the distance between the centre of support and centre of
gravity, and lessening the weight of the beam, and the quantity. of matter to be
weighed. The stability also increases with the weight, and the distance between
the two centres. As another step towards the perfection of the balance, we
must be careful that the centre C and the knife edges that support the scale-
Pans at L L, be in the same right line. If this be neglected, the beam becomes
f
#
#
R.:
§ Av


124 BALANCE.
a bent lever, and the weight of the body will appear to vary with the position
of the beam. The great difficulty of attaining an exact equality in the length
of the arms of a balance, renders it almost hopeless to attempt to obtain the
exact weight of any mass of matter by this means. It is fortunate, therefore,
that there is a method of weighing, which will enable us to dispense with one of
these, and uot the least difficult of attainment. The method of double weigh-
ing, introduced by Borda, renders the equality in the length of the arms a
matter of indifference. To ascertain the weight of a body by his method, we
place the body in one scale, as A, for example, then exactly counterbalance it
by small shot, sand, &c. placed in the other scale A, till the index points to O
on the scale at the foot of the pillar supporting the beam. The body is next
carefully removed from the scale A, and its place supplied by known weights,
until the beam again stands horizontal. The weights then in the scale will indi-
cate the weight of the body. As the weights, and the body to be weighed, have
both been placed in the same scale, and, consequently, at the same distance
from the centre, it is manifest, whatever may be the length of the arms, or their
weight, that the true weight of the body has been ascertained. That this method
may be completely efficient, only two conditions are required to be fulfilled.
The one is, that the distances between the centre C, and the points L L , con-
tinue the same during the operation of weighing; and the second is, that the
balance be exceedingly sensible, i. e. that it turn with the smallest possible
quantity of matter. The first of these conditions is fulfilled by making the
points L and L', of hardened steel, and sharpened to a knife edge, like the
point C, as, in this case, the motion of the beam will not sensibly change the
points of support, and, consequently, the distance between C and L will be
accurately preserved. The second condition is to make the balance sufficiently
sensible, which is accomplished by attention to the centre C, diminishing its
friction as much as possible. For this purpose, the planes that support the
knife-edge are highly polished; and, in order that they may be preserved in
their original state, the beam is not suffered to rest upon its centre but when in
actual use. To sustain it when not in use, the two forks, FF are employed,
which raise it from its support, and preserve it in a horizontal position. These
forks are movable by means of the handle N. When the balance is to be used,
the forks are lowered, and the beam set at liberty; and, as soon as the obser-
vation is completed, the forks are raised, and the beam elevated from its sup-
ports till again required. To preserve the balance from the motions that would
result from currents of air, it is sometimes inclosed in a glass case, having aper-
tures in it large enough to admit the substance to be weighed to be put into the
pans. When the instrument is not in use, it is recommended to place within
the case a small saucer filled with muriate of lime, or some other substance of
strong hygrometric power, to absorb the moisture that would otherwise settle on
the instrument, and destroy its polish by oxidation. In order to ascertain the
value of a balance, the scales may be removed from the beam, to see whether
the beam balances without them. They may then be put on again in opposite
sides, and tried. Equal weights should then be placed in each scale, and after-
wards changed to the opposite one; and if the beam maintains its horizontal
position during all these trials, it may be considered as accurate. The utility
of good balances for weighing different substances, is not limited to the accu-
rate performance of delicate experiments, but applies also to the saving of much
time in weighing, when a smaller degree of accuracy is required. If a pair of
scales, loaded with a certain weight, be barely sensible to one-tenth of a grain,
it will require a considerable time to ascertain the weight to that degree of
accuracy, because the turn is small, and must be observed several times over;
but, if a balance were used that would turn with the hundredth part of a grain,
and the weight was not required to any greater accuracy than the tenths of
grains, a single tenth of a grain, more or less, would make so great a differ-
ence in the position of the beam, that it would be seen immediately. If a
balance be found to turn with a certain additional weight, and is not moved by
any smaller weight, a greater sensibility may be given to it by producing a
vibratory, or tremulous motion, in its parts. If the edge of a blunt saw, file,
BALANCE. ** 125
or similar instrument, be drawn along any part of the case, or support, of a
balance, it will produce a jarring which will diminish the friction on the moving
parts so much, that the balance will turn with a third or fourth of the addition
that would otherwise be required. In this way, a beam that would barely
turn with one-tenth of a grain, may be made to turn with a thirtieth or
fortieth of that quantity. The improvement in the balance has progressed
with the general advance of the mechanic art, to such an extent, that it would
seem impossible to attain a higher degree of perfection than that which has
been attained in the construction of some modern balances. Mr. Read's balance,
described in the sixty-sixth volume of the Philosophical Transactions, readily
turned with one pennyweight, when loaded with fifty-five pounds, but distinctly
turned with four grains, when tried more patiently. This is about ºn part of
the weight. In the same volume, a balance, by Mr. Whitehurst, is described,
which weighed one pennyweight, and turned with in of a grain, or ii of its
weight. Ramsden's balance, turning on points instead of edges, is described in
the seventy-fifth volume of the Philosophical Transactions. With a load of four
or five ounces, a difference of one division in the index was made by lºs of a
grain. This is asſº of the weight, and, consequently, this beam will ascertain
the weight correctly to five decimal places. The Royal Society's balance, which
was recently constructed by Ramsden, turns on steel edges upon planes of
polished crystal. Dr. Ure states, “I was assured that it ascertained a weight
to the seven millionth part. I was not present at this trial, which must have
required great care and patience, as the point of suspension could not have
moved over much more than the two hundredth of an inch in the first half
minute; but from some trial, which I saw, I think it probable that it may
be used in general practice, to determine weights to five places and better. The
assay balance is of a similar kind to that which is here described in detail, but
small, and extremely delicate. It is used in docimastical operations, to deter-
mine exactly the weight of minute bodies. The beam should be made of the
best steel, and of the hardest kind, as this metal is less apt to be spoiled with
rust than iron, and it more easily takes a perfect polish, which, at the same
time, prevents the rust. The longer the beam is, of course, the more exactly
may the weight be determined; but, in general, ten or twelve inches is con-
sidered a sufficient length. The thickness of it should be so small, that two
drachms might hardly be hung at either end without its bending; for the largest
weight put upon it seldom exceeds one drachm. The whole surface of the beam
should be without ornament, as these only collect dust, and render the balance
inaccurate. The whole apparatus is, when used for nice experiments, enclosed
in a case with glass faces, and which are opened only so far as may be neces-
sary to introduce the weights and the body to be weighed.
Balance Hydrostatic, is a balance furnished with apparatus adapted to ascer-
tain the specific gravity of bodies, by weighing them in liquids, as well as in air.
A common balance, of a good construction, and furnished with a small hook
beneath one of the pans, is, with the usual appendages, quite sufficient for a
hydrostatic balance. An accurate and delicate balance, that may be adapted
to this purpose, and is easily constructed, is thus described in Brewster's Philo-
sophical Journal. Let a slender beam of wood €
be procured, about eighteen, or twenty-four
inches long, and tapering a little from the
middle to each end. Let a fulcrum of tem-
[. steel, resembling the blade of a pen-
nife, be made to pass through the middle of
the beam a little above the centre of gravity.
Sinmilar steel blades are also made to pass
through the ends of the beam for suspending
the scales. The fulcrum rests on two small
portions of thermometer tubes, fixed horizon-
tally on the upright support ef. The support
has a slit along the middle, to allow the needle at ef to play freely between the
sides. A small scale, made of card, and divided into any number of parts, is

A v.
126 BALANCE.
placed at f for the purpose of ascertaining the point at which the needle remains
stationary. This balance possesses extreme delicacy. It may even be made
more sensible than that belonging to the Royal Society of London. I have said
nothing of the perfect equality of the two ends, as this condition is not at all
necessary to the accuracy of the balance, according to the method of double
weighing. To ascertain the weight of any body, place it in one of the scales,
and bring the needle to any point by means of small shot placed in the other
scale; observe the point opposite to which the needle rests, or the middle, be-
tween its extreme points of oscillation; remove the body, and put into the
same scale as many known weights as will bring the needle to the same division
as before. These weights will, evidently, be equal to the weight of the body,
whether the arms of the balance be equal or not. This method of weighing is
due to Bordà. . The steelyard is sometimes employed to ascertain specific
gravities, as in the balances of Lukin and Coates.
Lukin's Hydrostatic Balance is extremely simple, and is considered to be a
very accurate instrument. The appearance is given in the accompanying
figure. When unloaded, the arms are equipollent. C the body, whose specific
|
&ºr
gravity is to be found, is suspended to the shorter arm of the instrument. On
the longer arm, the movable weight D indicates the weight of the substance in
air or water. . If great accuracy is required, a second weight, which is a sub-
multiple of the first, may be added on the longer arm. Then the division
marked by the larger weight may be units, and that of the smaller, tenths, or
hundredths, as may be thought proper.
Coates's Hydrostatic Balance is upon the same principle as Lukin's, but differs
in the mode of graduation. This being adapted for finding the specific gravity of
minerals, instead of pointing out the actual and relative weights, it shows at
once their specific gravity. The instrument is accurately balanced when un-
loaded, by making the shorter arm much larger than the longer one; and the
latter is graduated, and marked with numbers, which every where show the
quotient of the entire length of the longer arm, divided by the distance of the
given mark from the end. Thus, at half the length, is marked the number 2;
at one-third, the number 3; and so on. These numbers extend on the scale to
rather more than 20, in order to render the instrument applicable to the heavier
metals. In using this instrument, a weight is suspended by a hook at A, and
the body under examination is to be hung by a horse hair on the shorter arm,
and slid along as on the steelyard, till an equipoise is obtained, say at D. Then
without altering its situation on the beam, the body is to be immersed in water,
and balanced a second time, by sliding the weight C along the graduated arm,
till the two are again in equilibrio. The hook of the weight will then at once
indicate, by its situation on the scale, the actual specific gravity of the body,
water being considered as unity. The instrument being supposed in equilibrio,







BALANCE. # 127
and the distance B D and the weight of the counterpoise being constant, the
weight of the body varies as the distance of the counterpoise from B. Thus, if
the counterpoise have to be removed 3 nearer to the centre B, to balance the
body when weighed in water, the specific gravity, as seen on the scale, will be
4, or four times greater than that of water. If it have to be removed # nearer,
the specific gravity is 12, and so on. The truth of the principle will appear, if
we consider that the specific gravity of any body, as compared with water, is
found by dividing its weight in air by its loss of weight in water. Now its loss
of weight in water is proportional to the approximation of the weight C towards
the centre. If, therefore, the whole arm, which always represents the weight
in air, be divided by the quantity by which the weight approximates to the
centre, it is clear that the quotient which is marked on the scale will be the
true specific gravity required.
The annexed figure represents a balance beam, invented by Mr. J. H. Patten,
Rhode Island, United States, for the purpose of taking the specific gravities of
different bodies, and for the accurate weighing of minute quantities. The
manner of using the instrument, it will be seen, is similar to that of Lukin'
balance, just described. The beam a b c is made of steel sufficiently strong,
but light. The dish is suspended at a ; the beam itself upon an axis at b : at
c is the milled head of a long screw, which is fitted with a shoulder and axis,
and goes through the slide e that traverses upon b c, and carries the weight d.
Now, suppose it required to obtain ten grains, place that weight in the dish f,
and screw back the weight d until it exactly counterbalances it. If the weight
be now removed, and a quantity of the substance to be weighed be substituted,
until the index points to where it did at first, there will then be very nearly the



128 - BAIANCE.
exact weight, differing only by the amount of the friction of the instrument.
This beam may be used as a steelyard, by screwing the weight d to any number
marked upon the scale ; and should a greater quantity be required than that
marked in the first line, another weight, double that of d, may be substituted.
The ancient balance was the statera, or steelyard, in which the arms are of
unequal length, and one movable weight is used, placed at different distances
from the centre of motion, or fulcrum. The annexed figure represents the
common steelyard, in which c is the
fulcrum, or centre; c b the longer arm, O
and c a the shorter, e is the article to z &/ 2
be weighed, suspended to the shorter C(9) (9) CITILITILITE-Iſ- 0
arm, and d the constant weight. Now, all----
if the shorter arm, by its additional
thickness, be a counterpoise to the d
longer, so that the beam, when un-
loaded, may hang in a horizontal
position, it is manifest, that equal weights, hung at equal distances from the
centre, will balance each other; but if one of the weights be removed further
from the centre, that side will preponderate. From this, it appears that a large
weight e suspended at b, may be counterpoised by a small one suspended at d.
If the distance between c and d be nine times greater than that between c and e, a
weight of 10 lbs, at d will counterbalance one of 90 lbs. at e. To prevent the
necessity for calculation, the longer arm is graduated, so that the exact weight
may be known by inspection.
The Danieſ, Balance is also a steelyard, but in this the weight is fixed at one
end, the article to be weighed at the other, and the fulcrum, or support, movable
between them. In the annexed cut,
b represents the standard weight, and
a the hook, to which the article


whose weight is required, may be sus- a &
Pended, and dis the movable fulcrum, ſimrrrrrrrrrr HF- &n
If a b were supposed a perfectly t —|| | |-)
straight rod without weight, the gra- S c”
dations on it should be at equal dis-,
tances; but as this cannot be the ' '
case in practice, a different arrange- -
ment is required. If c be the centre of gravity of the beam, and the fulcrum
be placed at this point, it is clear that the beam will be supported in an hori-
zontal position; but if a weight be appended to the hook a, the centre of gravity,
which in all cases must be supported, will be removed to d, for example, and,
consequently, the fulcrum must be moved to the same point. In this case,
there is not only a difference in the leverage, or length of the arms, but there
is the weight of the portion c d taken from one side and added to the other.
The best method of graduating this instrument is by experiment, by applying
known quantities at the point a, and marking the place of the fulcrum d when
an equilibrium takes place.
The Chinese Balance is a steelyard, somewhat different from the Roman
statera. It is much used by the Eastern merchants in weighing gems and
precious metals. The beam is a small rod of wood or ivory, about a foot in
length. Upon this there are three lines of measure, made of delicate silver
studded work. The scales commence at the end of the beam, whence the first
extends to 8 inches; the second to 64; and the third to 8%. The first indicates
European weight, and the other two Chinese. At the other end of the beam a
scale is suspended; and at three several distances from this end are fastened so
many fine strings, forming so many different points of suspension. The distance
of the first point from the end is ; of an inch; the second #; and the third #.
When the instrument is used, it is hung up by one of the strings, and a sealed
weight of about 14 oz. is hung upon some one of the divisions of the rule, so as
to counterbalance the weight of the article, which is indicated by the graduations
of the scale.
^- **
BALANCE, 129
. The Bent Lever Balance is represented in -fºr-f
the annexed figure, in which a c 0 is a bent l_V2 $
lever, moving on the centre c as its fulcrum, E % ;
or axis, of motion. To the shorter arm of the \
lever at b, a scale-pan e is appended, while
the other arm has a heavy weight affixed to *
its other extremity a, which passes over the /~
º arch f # Tº: * º -.
weighed being placed in the scale e, the en S - \-—-
(Z j ...”. weight by the height to `s-
which it rises on the graduated arch. A little 3/*
attention to the diagram will show that, as the
end b descends, the other extremity a ascends, **
and, at the same time, removes to a greater \
distance, from a vertical line passing through —F-l—N.
the centre of motion. In the present posi-
tion of the balance, the effective length of the arm c b, is ki, and of the arm
ca, is k d. Now, as these are of equal lengths, the weight a (omitting the
weight of the lever itself) will be equal to that of the substance placed in the
scale. But as the weight approaches the point g, the effective length of a c will
be represented by k h, and the weight a will therefore act with as much more
power, as the length of k h exceeds that of k d. If the point continued at the
same distance from the vertical line, passing through c, the efficacy of the
weight would, at any point in the arch, be proportional to the length of a per-
pendicular drawn from that point to the vertical line; but as the distance of b
is constantly varying, we can only state, generally, that the divisions will be
nearer together as we approach the upper part of the scale.
Payne's Weighing Machine is of the steelyard kind; the longer arm is divided
*-----— |
a ||4
J


130 BALANCE.
by lines denoting the various weights, as usual; but, instead of the weights
being suspended by hooks immediately on the beam, they are attached to a long
case, or box, which slides with some friction along the beam. Beneath one end
of this sliding box is a large hook, to which is suspended the heavy weight,
which is used to measure the larger quantities, as hundred weights, and quar-
ters, which are denoted by the divided lines on the beam, as the sliding box is
drawn over it. To measure the smaller quantities, as pounds and ounces, there
is a light scale of parts fixed to the top of the sliding box, to which a hook and
weight are hung, which are applied in the same manner as the common steel-
yard. In the preceding engraving we have given a view of the whole arrange-
ment, the longer arm of the beam being somewhat shortened to save room. In
this representation, a a is the beam; c is the fulcrum; d a long rectangular
loop through which the arm a a passes, and which serves to support it when not
in use, or to limit its vibrations when employed in weighing; e is the sliding-
box, with its graduated scale, for the minuter quantities, which are to be ascer-
tained by the smaller weight g; f the larger weight, which may be secured at
pleasure, at any point, by means of a thumb-screw above, half a turn of which
fixes the slide against the beam, while the more minute quantities are being
taken. The goods are placed in the scale h, which may then be raised from
the ground by turning the handles k k, which causes the screw i to enter the
nut above. Machines on this principle are made of all sizes, to weigh either
tons Or OunceS.
Braby's Balance, or Weighing Apparatus, unites the properties of the bent
lever balance, and the steelyard. It has been termed a domestic balance by the
ſº - - -----
º:
# i
Ø #, jº
- sº
... 'ſtºli Wº.
- º, Fº |
º º 6
º
º |
§ *Fººd iſ 1:
º §º
inventor, fromi. A being peculiarly adapted for family purposes, such as weigh-
ing meat, bread, butter, &c. In the figure A B C is a frame of cast-iron,
which has the greater part of its weight towards A, in consequence of its







BALANCE. 131
~~~~ * ~-- al-‘ -i------ ~ + 4* r * ~~~~ * T - - £-->4 £:1-------- ~~~.4 F (T = ---...-.......! -
83 cave a villeniless a v v^** Pº v. -a is a 1140 cu i u : v i li 11, 3 tº 1 1 UA all 11 & 11 it J W dºle SliS-
pender, which has a scale and hook at its lower extremity. E K G are three
distinct points to which the suspender E H may be applied, and to which belong,
respectively, the three graduated scales of weights f C, c d, a b. When the
suspender is applied at G, the apparatus is in equilibrio with the edge A B hori-
zontal, and the suspender cuts the zero of the scale a b. If a weight be now
placed in the scale, the whole apparatus turns about F, and the point on the side
B C descends till the equilibrium is again established. The weight placed in
the scale may now be read off from the point where the suspender cuts the
scale a b, which registers to ounces, and is adapted to bodies whose weight does
not exceed two pounds. If the weight of the body exceeds two pounds, but is
under eleven, the suspender is placed at K; and when the upper edge of the
balance is horizontal, the weight, or number 2, is found a little to the right of
the index of the suspender; if, now, weights exceeding two pounds be placed in
the scale, the whole again turns about F, and the weight of the body is shown
on the graduated arc c d, which extends to eleven pounds, and registers to
every two ounces. If the weight of the body exceeds eleven pounds, the sus-
pender is hung on at E, and the weights are ascertained in the same manner
on the scale f C to thirty pounds; the subdivisions on this scale are quarters of
pounds. The same principle might be extended to weights greater than the above.
To prevent mistake, the three points of support, G, K, E, are numbered 1, 2, 3;
and the corresponding arcs are respectively numbered in the same manner.
When the hook is used instead of the scale, the latter is turned upwards, there
being a joint at H for that purpose.
Balance of Torsion. If a piece of very fine wire, silk, or spun glass, ex-
tended by a weight, be suspended to any fixed point, and then twisted, it will,
when released, begin to untwist itself, and, by its momentum acquired in the
act of untwisting, will twist in the opposite direction. It will afterwards return,
and thus, by a series of oscillations, continually diminishing in amplitude, it
will at length come to a state of rest in its original position. Now, if a needle,
or an index similar to the hand of a watch, be attached to the lower extremity
of the suspended wire, and a circle, having its circumference graduated into
degrees, or other equal divisions beneath it, it will form the balance of torsion.
To measure small forces, as those of electricity, magnetism, &c., with this
balance, they are made to act on one extremity of the index; and when the
force is in equilibrio with the tendency of the wire to untwist, the angle which
the index makes with its quiescent position, which is called the angle of torsion
is the measure of the force employed. In the annexed 9
cut, let a b c g represent the graduated circle, and a g
the index suspended by the silver wire at the point e.
Suppose any force act upon a so as to move it to b, then
will the arcs a b represent the angle of torsion. Sup-
pose another force to act at the same distance, and
move the ball to c, then will the latter force be mea-
sured by the arc a c ; and hence the intensity of the
former force is to that of the latter, as a b to a c. To
preserve the index from disturbance by the air, the whole is enclosed in a glass
cylinder, at the upper part of which, where the wire is attached, there is an index
and a divided circle, which is used to twist the wire, when the measure of a force
becomes greater than a whole circumference. The sensibility of this instrument
will depend on the dimensions of the suspending wire. Thus, if the length of the
wire be doubled, the sensibility will be increased in the same proportion, i. e.
only half the force will be required to twist the wire a given number of degrees.
If the diameter of the wire be increased, the sensibility is diminished in a great
degree; thus, if there be two wires of the same length, but one twice the thick-
ness of the other, the latter will require sixteen times more power than the former
to twist it through a given number of degrees; the force of torsion being pro-
portional to the fourth power of the diameter, and sixteen it will be seen is the
fourth power of two. If the wire be increased three times in diameter, the
sensibility will be decreased 3 × 3 × 3 × 3 81 times.

132 BALING MACHINE.
Balance of a watch, is that part
which, by its motion, regulates and
determines the vibrations. The cir-
cular part is called the rim, and its
spindle the verge; there also belong
to it two pallets, that play in the
fangs of the crown-wheel. In
pocket watches, the strong stud in
which the lower pivot of the verge
plays, and in the middle of which
OI) e. i.” of the crown-wheel runs,
is called the potence ; the wrought
piece, which covers the balance,
and in which the upper pivot of the
balance plays, is the cock; and the
small spring in the new pocket-
watches, is called the regulator.
The motion of a balance, like that
of a pendulum, being reciprocating,
while the pressure of the wheels is
in one direction, it is obvious that
some contrivance must be used to
accommodate one to the other.
When a tooth of the wheel has
given the balance a motion in one
direction, it must quit it, that it
may obey an impulsion in the op-
posite direction. The balance, or
pendulum, thus escaping from the
tooth of the wheel, or the tooth
escaping from the balance, has
given to the general construction
the name of scapement. See HoRo-
LOGY.
BALING MACHINE. A ma-
chine for raising water from the
hold of ships. When, from the
pumps being rendered useless by
an accident, or from the extent of
a leak, the water gains upon the
pumps, the method usually resorted
to for getting rid of it, is to bale it
out at the several hatchways, by
means of canvas buckets; but from
the difficulty of filling and raising
the buckets, from the heavy rolling
of the vessel, the most painful and
long continued exertions prove in-
sufficient to save a ship from foun-
dering. An apparatus, of great
simplicity of construction, and faci-
lity of application, for the purpose
of baling, has been invented by Mr.
J. Dennett, of the Isle of Wight,
which will, no doubt, be found a
powerful auxiliary to a ship's pumps
in cases of danger. The annexed
figure is a perspective view of this
machine. a and b are part of the
hatchways of the upper and lower

BALLISTIC PENDULUM. 133
decks; c c is a long rebated slide, in an inclined position, reaching from a little
above the coamings of the upper deck, to the ballast in the hold; e is a square.
bucket, made to slide on the rebate c c ; its bottom is a flap valve, so that when
it slides down into the water, it opens, and the bucket fills instantly, and closes,
upon being drawn up full of water, without any attention on the part of the work-
men. The upper portion f of the rebate of the long slide is made detached, and is
fixed in its place by the ping, on which it turns as on an axis. The bucket is shown
discharging the water on the upper deck; and when the rope h : k is let go, the
bucket falls down, rights itself, and the upper portion f of the slide falling with
it, and joining the lower part, the bucket runs down the whole of the slide into
the water, is instantly filled, and drawn up again by pulling the parts i k of the
rope, the part k passing through a leading block m on the deck. A pin is fixed
on the top of the rebate, so that when the bucket rises up, and is only in the loose
portion f, it is stopped by the pin; and the loose portion f, by farther pulling,
rises out of its place, and upsets the bucket. To prevent the bucket being raised
higher than is necessary to discharge the water, a knot is worked in the rope,
which forms a stop against the block l. The block l is made fast to a yard-
arm, and the upper end of the rope k is secured to the same, or elsewhere, with
just length enough to let the bucket reach the bottom of the slide.
BALLAST. Heavy substances placed in the lowest part of the hold of a
ship, to preserve the vessel in an upright position, when under sail. It consists
generally either of masses of cast-iron 3 feet long and 6 inches square or of
small round stones, which is called shingle ballast.
BALLAST LIGHTER. A vessel employed to remove sand, silt, or other
depositions from the beds of rivers, harbours, docks, &c. which is effected as
follows: The vessel, which is a species of open barge, being moored, a leather
bag, the mouth of which is distended by an iron hoop, fastened to a pole of
sufficient depth to reach the bottom, is put over the side, and descends to the
bottom in an inclined position; two or three turns are taken with a rope
round the pole, and a timber-head near the stern of the boat. A rope attached
to the hoop of the bag, and passing over a small crow at the fore part of the
vessel, is then brought to a winch, and the bag is gradually wound up by a man
at the stern slowly slacking the rope which passes round the pole, thus allowing
it to rise as it approaches the vertical position; at the same time causing such
friction, that the edge of the hoop digs into the ground, and the leather bag
receives whatever passes through the hoop. When the bag is raised above the
side of the boat, it is swung into the boat by the crane, and its contents dis-
charged into the bottom of the vessel. -
BALLISTA. A machine used in ancient warfare for throwing stones or
darts. It in some measure resembled the cross-bow, but possessed far greater
projectile power. It has been thus described : An iron cylinder was fastened
between two planks, from which proceeded a hollow square beam, placed cross-
wise, and fastened with cords, to which were added screws. At one end of this
stood the engineer, who put a wooden shaft with a large head into the cavity of
the beam; this done, two men bent the engine, by turning some wheels. When
the top of the head was drawn as far as the cords would allow, the shaft was
driven out of the ballista. The ballista depended and acted. upon the same
principles as the catapulta, the moving power of which depended on the elas-
ticity of twisted cords, made with women's hair, that of horses, or the entrails
of animals. The ballista was usually employed in throwing darts, though, like
the catapulta, it sometimes was used in projecting large stones. It is recorded
by Vegetius, that the ballista discharged darts with such velocity and force, that
nothing could resist their power: and Athenaeus adds, that Agistratus made one
of little more than two feet long, which shot darts 500 paces.
BALLISTIC PENDULUM. An ingenious machine, invented by Mr. Ben-
jamin Robins, for ascertaining the velocity of military projectiles, or the force of
fired gunpowder. It consists of a large block of wood, fixed to the end of an iron
rod, and suspended like the pendulum of a clock. When the pendulum is at rest,
a gun is pointed towards the centre of the block, and a ball fired point blank
into it In consequence of the magnitude of the block, compared with the ball
S
134 BALLOON.
or bullet, a very small velocity is given to the former, which being accurately
measured, the velocity of the ball is easily deduced; for, as the weight of the
ball is to the sum of the weights of the ball and block, so is the observed velocity
of the block to a fourth quantity, which is the velocity of the ball sought. A
variety of experiments have been made by Dr. Hutton with this pendulum,
from which a number of useful rules have been deduced relative to the velocity
produced with different charges of powder, with guns of different lengths, and
with different sized balls. A complete series of experiments was also instituted
relative to the resistance of the air to different velocities, varying from 0 to 2,000
feet in a second. Among other results, he ascertained that inflamed gunpowder
expands itself with a velocity of about 5,000 feet in a second.
BALLOON, in Chemistry, a glass vessel to receive the product of distillation.
BALLOON, AIR. A bag made of silk, paper, or other light material, for
containing heated air, or gas, of less specific gravity than the atmosphere. If
the weight of the balloon, and of the heated air or gas which it contains, be less
than that of an equal bulk of atmospheric air, the balloon will ascend in con-
sequence of the equilibrium of atmospheric pressure being disturbed; the pressure
of the column of which the balloon forms a part, being less than that of the
ordinary atmosphere. The ascending, or upward pressure, therefore, carries the
lighter body up until it arrives at a more attenuated medium, which is of the
same specific gravity. After the discovery of hydrogen gas, the lightest of all
ponderable substances, it occurred to Dr. Black, that a thin bag filled with this
would ascend in the air. He suggested the employment of the allantois of a
calf for this purpose, but Mr. Cavallo, who performed various experiments on
this subject, found that this, and the lightest bladders he could procure, were all
too heavy. Chinese paper was also tried, but the gas escaped rapidly through
it. By filling soap-sud bubbles with hydrogen gas he succeeded, and these
balloons rapidly ascended to the ceiling. Within these few years small experi-
mental balloons have been formed of the crop of a turkey, which, when the
fat, &c. have been separated, are sufficiently light to ascend if filled with hy-
drogen gas, although some of them do not contain more than a pint. At about
the same period of time, two brothers, named Montgolfier, natives of Annonay,
in France, were trying experiments with balloons filled with heated air, the
specific gravity of which is less than that of air at the ordinary temperature.
They were led to these experiments by observing the rapid ascent of smoke
from chimneys, and imagined that if the smoke were confined in a large and
light bag, it would be borne upwards. A bag of fine silk, in the shape of a paral-
lelopiped, was constructed, and burning paper was held under the aperture,
until the balloon contained a sufficient quantity of rarefied air to carry it up to
the ceiling of the apartment. When this experiment was repeated in the open
air, the vessel ascended to an altitude of about 70 feet. Other balloons on a
larger scale were constructed, and a public exhibition of one containing 23,000
cubic feet was made at Annonay, on the 5th of June, 1783. This was formed
of linen lined with paper, and when filled with heated air, was capable of raising
500 lbs. appended to the extremity. One of the Montgolfiers shortly after this
visited Paris, and as the affair had excited much attention, he was invited by
the Academy of Sciences to repeat the experiment at the expense of the Society.
A large balloon, of elliptic shape, was filled with heated air, in the presence of
the members, and in this state it would have ascended with a weight of 500 lbs.
if the cords which prevented it had been liberated. As it was intended to
exhibit the ascent before the king of France and his court, this was not done,
and the balloon was subsequently so much damaged by wind and rain, that it
became necessary to construct another. This was nearly 60 feet in height, and
43 in diameter, and a wicker cage was attached to it, containing a sheep, a
cock, and a duck. The balloon, when duly prepared, ascended with these to an
altitude of about 1,400 feet, and would have ascended to a greater height had
not a violent gust of wind torn the cloth, and permitted the heated air to escape.
The facility of ascending in the atmosphere being thus fully established, Pilatre
de Rozier offered personally to ascend in another balloon, to be constructed by
Montgolfier. Accordingly another balloon was completed, of enormous mag-
BALLOON. 13.j
nitude. The height was 74 feet, and the diameter 48; and its weight, including
the car and necessary fuei for continuing the fire, was 1600 lbs. By this the
intrepid Pilatre de Rozier made several ascents to an altitude of from 200 to 330
feet, but in these preliminary attempts the balloon was confined by cords.
Subsequently he ascended in company with the Marquis d’Arlandes, with the
balloon unrestrained, and they continued in the air about 25 minutes, and
descended at a distance of about five miles from the place of their departure.
The difference between the specific gravity of air heated by the means employed,
and that of air at ordinary temperatures, not being very considerable, the buoyant
power of a balloon thus filled, was comparatively small, and therefore it was
indispensable to employ a large quantity, and, consequently, a large machine to
contain it. To double the volume of air by heat, requires a temperature of
nearly 4800 Fahr. Messrs. Charles and Roberts therefore tried the experiment
of filling a silk bag only 13 feet in diameter, with hydrogen gas, which is only
# the weight of ordinary air. The experiment was perfectly successful. This
small balloon was capable of raising 35 lbs., and on being liberated, it ascended
to a considerable height, and after remaining three-quarters of an hour in the
air, descended at a distance of fifteen miles from the spot where it had ascended.
A balloon formed of silk, and varnished with a solution of Indian rubber, was
then constructed, which was filled with hydrogen gas. The diameter was 27;
‘eet, and it was covered with a net-work, to which a car, capable of holding two
persons, was attached. Messrs. Charles and Roberts ascended from Paris in
this, in December 1783, and after remaining in the air an hour and three
quarters, they alighted at a distance of 27 miles without accident. A sufficient
quantity of gas still remained in the balloon to carry up one person, and
Mr. Charles again ascended alone, and attained an altitude of more than 10,000
feet. Shortly after this successful effort, attempts were made to guide or impel
a balloon in any required direction; and if this could have been accomplished,
the invention would have introduced a new era in science. Mr. Blanchard
applied a species of wings to the car, but was unsuccessful in his attempt to
travel against the direction of the wind; nor was Morveau more fortunate with
large oars or sails, introduced with the same design. Numerous contrivances
have been since adopted, but all have been ineffectual in practice; and, indeed,
when the great extent of surface which a balloon presents to the impulsive
force of air in motion is duly considered, the probability of overcoming that
force by any means which can be commanded by the aerial voyager, seems very
remote. Endeavours have also been made to economize the gas which the
balloon contains. A much larger quantity than is necessary to create the
buoyant power required to carry up the voyagers, is introduced, and to occasion
the descent of the machine, the gas is permitted to escape by a valve; but if
the aeronaut require again to ascend in consequence of the unfavourable nature of
the ground on which he is likely to descend, or from any other cause, he
must part with ballast, which may be essential to his safety. The Duke de
Chartres, accompanied by Charles and Roberts, ascended in a balloon filled with
hydrogen gas, which contained a smaller within it, to be filled with common
air, by means of a pair of bellows, as occasion might require. By inserting
common air into the small balloon, the specific gravity of the machine would
be increased, and it would descend without loss of gas, and reascend by with-
drawing the common air. However ingenious the contrivance, it was not
found successful in practice, chiefly, perhaps, on account of the unfavourable
state of the wind, which was tempestuous when the experiment was made.
Pilatre de Rozier and Mr. Romaine, with the same design introduced a bal-
loon filled with heated air below the ordinary balloon containing hydrogen
gas. The buoyant power of the heated-air balloon was equal to about 60 lbs. ;
and by removing the source of heat, the specific gravity of the whole machine
was increased, so that it was not necessary to part with any gas during a voyage.
The attempt to carry this plan into execution was fatal to both voyagers. The
upper balloon, by means unknown, took fire, and the intrepid De Rozier
and his companion were precipitated to the earth and killed. It is not our
purpose to describe the various attempts that have been subsequently made to
136 BALLOON
improve the construction of balloons, or to render them subservient to scientific
purposes, since little has been effected towards accomplishing these objects. We
cannot, however, omit a description of an addition to the balloon, called a
parachute, which was first employed, with daring courage, by M. Garnerin.
The balloon was of the usual form, made of oiled silk, and filled with inflam-
mable gas; it was covered, as represented in the annexed engraving, with a
netting, from which cords proceeded that were tied together at a few feet below
the balloon; the several cords thus collected were then twisted so as to form a
2.º:.
2
3.
$2.
E.
º
º
E
-
#: ----->
. : | SESE.
| ->- st:
single rope, which was passed through the parachute, and fastened to the car,
or basket. The real structure of the parachute is best seen in its expanded
state, as shown in the descent, forming a near resemblance to a large umbrella;
it was made of canvass, and about thirty feet in diameter; it had no ribs,
the figure of its dome being preserved by the surrounding cords. The length
of these cords, or ropes, from the edges of the dome of the parachute, to where
they are connected together, was about 30 feet; and from this point of connexion,
other shorter ropes proceeded, which were attached to the edges of the circular
basket in which the aeronaut was situated. In the place of the handle of a com-
mon umbrella, a long in tube was fixed in the parachute, through which the
single rope before-mentioned was passed, to prevent its becoming entangled,
and to allow it to slip away with certainty when severed for the purpose of de-
scending. The ascent took place on the 21st of September, 1802, from St. George's
Parade, North Audley-street. The balloon began to be filled about two o'clock; 33
casks filled with diluted sulphuric acid, together with a quantity of iron filings, were












BALLOON. 137
employed for the production of the hydrogen gas. These communicated with three
othor on sl-5 ov. …an aval recoivors to aoch of which wras offived a #11 he that enn ntiań
* A & wºme w is ºne sº ºw.a.a.a...º.º. º. ºº we “w r- ºr * *- - *** *
**.*.*.*.*.*. vºv; ** A. * *** * ~ * ~ * * ~ * ~7 v-, - wwaz va " " -- ~~~~ - • **** w
itself into the main tube connected to the balloon. At six o'clock the balloon
was completely filled; when it rose with its long appendage of the parachute, the
aeronaut in the little basket closing the train. Thousands of acclamations rent
the air, while the eyes of tens of thousands of spectators were fixed in astonish-
ment and admiration at the gallant adventurer; feelings which could be only
surpassed by the most intense and painful anxiety for his safety. The weather
was beautifully fine, with scarcely any wind. For eight minutes this intrepid man
continued to ascend, till he arrived at such an immense height as to be scarcely
visible, when he cut away the balloon. The parachute did not expand imme-
diately, and he fell with great velocity for a short space of time; when it opened,
and his descent became gradual, but attended with a remarkable oscillation, like
the pendulum of a clock, to that degree, at one time, that the parachute, cords,
basket, and aeronaut, appeared to be stretched in an horizontal line. At length,
as he approached the earth, these vibrations were less extended, and continued
to diminish till he reached the ground, which he did without any injury to him-
self, or the apparatus, which he brought down with him, in a field near the
Small Pox Hospital, at Pancras. The balloon was observed to ascend rapidly
after separation from the parachute, and was soon out of sight. It has been
suggested to combine the parachute with the balloon so as to add nothing to the
bulk, and but little to the weight of the machine; it is as follows:—The band
which divides the upper hemi-
sphere of the balloon from the . * -
lower one, is to be formed of a #-F. . – *=_
wooden hoop, to which the - *-ammº-
net-work which covers the #
upper hemisphere, is to be äs ,
firmly attached ; the cords; /*
which descend from this hoop,
- **-
-
––
are to be fastened together in tº #=
the usual manner, below the à T =
balloon, but not attached to : Nº ===
the lower hemisphere; now, if = --_#
the upper hemisphere of the #~\\ ==
balloon should burst, the gas - -E-E-
would escape, the balloon would ==
begin to fall, and the lower Tº
hemisphere would immediately #A -
fall into the direction here re- =} - ... --
presented, lining the upper -
one, and forming a complete
parachute. Should the lower
part burst, the escape of the
gas would not be so sudden as
in the former instance; but when it had escaped, and the balloon began to fall,
it would immediately form itself into the same shape as before : in this latter
case, it would, perhaps, be better to open the valve at the top, by which means
the balloon would sooner be formed into the shape of a parachute. This plan
has, perhaps, these advantages over the common parachute; viz. 1st. That of
taking up less room ; 2d. Being less weighty : and 3d. Not being subject to
that great and sudden fall which must render the use of the common parachute
not only unpleasant, but extremely dangerous.
Mr. Green, who has made more than two hundred successful ascents, first
employed the ordinary coal gas, in lieu of hydrogen, or heated air, to gain the
buoyant power. As the specific gravity of this is considerably greater than that
of hydrogen, it is necessary to employ a large balloon when coal gas is used.
Mr. Green's present balloon contains about 24,000 cubic feet. There is much
economy in using this substitute, as the cost price of sufficient coal gas does
not exceed twenty pounds; but the expense of generating as much hydrogen









1 38 BAMBOO.
gas as the balloon requires, amounts to nearly a hundred pounds. The latter
product of the distillation of coal, when the more valuable illuminating gas is
evolved, answers the purpose best, as it contains much less carbon, and is, con-
sequently, considerably lighter. The best material for constructing a balloon,
is the silk stuff called lustring. When cut into gores it should be stretched by
weights, or other means, and kept in this state several hours before it is var-
nished or sewn. It is usual to apply boiled linseed oil, containing a small
quantity of oxide of lead, for the first coat of varnish, and a solution of caout-
chouc (Indian rubber) in oil of turpentine, for the last. The seams should
be doubly sewn and overlapped; and, when finished, a hot smoothing-iron
should be passed over them, the silk being protected by an intervening sheet of
paper. The gores should be cut with great precision. A net-work of strong
hempen twine should be accurately fitted to the balloon, the meshes at the
upper extremity being smaller than those below. To the separate cords which
terminate the net-work, a circular hoop is attached, from which the car is sus-
pended by strong ropes. The whole of the net-work and ropes should be so
adjusted, that the strain, or pressure, is equalized over the whole surface of the
balloon. The valve for permitting the escape of gas must be retained in its
place by a sufficient spring; and to render it perfectly air-tight, a luting of wax
and oil is generally employed around the edges. The cord by which the valve
is opened passes through the interior of the balloon; and great care is neces-
sary to prevent it being entangled. The extremity of this cord should never be
fastened to the car, as in the event of its oscillation, the valve might be opened,
and retained in that state until the greater part of the gas escaped. A grap-
pling-iron, attached to a strong rope, is an indispensable appendage to a bal-
loon. As much ballast as can be taken should always be employed. It
frequently occurs that the aerial voyager is far above the clouds, and loses sight
entirely of the earth by their intervention; on passing through them, he may
find that the spot on which he is descending is unfavourable. A few pounds
of ballast thrown out, will occasion the balloon again to ascend, and pass over the
inappropriate landing-place. The writer of this article was thus situated; and
all the ballast being discharged, he was in imminent danger of descending in an
arm of the sea. A contrary current, near the surface of the earth, however,
gave the balloon another direction, when escape seemed almost impossible.
The appearance of the scenery below to an aeronaut is inexpressibly beautiful;
but as a bird’s-eye view only can be taken, no correct opinion can be formed of
the altitude of buildings, hills, or trees. On this account, much of the grandeur of
an extensive prospect is lost. The chief inconvenience experienced is from
the sudden variations of temperature. The upper regions of the atmosphere
are intensely cold when the sky is cloudless, even although the sun be shining in
meridian splendour. In an ascent made in August, when the thermometer was
740 in the sun at the time of ascent, the writer observed, in less than twenty
minutes, that the mercury indicated a temperature of 319.
BALLUSTRADE. A series, or row, of ballusters, joined by a rail, serving
both as a rest, and as a fence or enclosure, to stair-cases, balconies, &c.
BALSAMS are vegetable juices, either liquid, or which spontaneously
become concrete, consisting of a substance of a resinous nature, combined with
benzoic acid, or which are capable of affording benzoic acid, by being heated
alone, or with water. They are insoluble in water, but readily dissolve in
alcohol and ether. The liquid balsams are copaiva, opo-balsam, Peru, styrex,
and tolu; the concrete are benzoin, dragon's blood, and storax.
BALSAM OF SULPHUR. A solution of sulphur in oil.
BALDWIN'S PHOSPHORUS. Ignited nitrate of lime.
BAMBOO is a native of the hottest regions of Asia. It is likewise to be
found in America, but not in that abundance with which it flourishes in the old
world. It is never brought into this country in sufficient supply, though it is ad-
mirably adapted for many purposes. In the countries of its production, it is one of
the most universally useful plants, and of the most rapid growth, rising from fifty
to eighty feet the first year, and the second, perfecting its timber in hardness
and elasticity. It grows in stools, which are cut every two years. Its young.
BANDANNAS. 139
shoots and roots make an Indian pickle; its light, graceful, knotted stalk, is
used in many articles of furniture for the rich; and its timber forms almost
entire houses for the lower orders. The quantity of timber furnished by an acre
of bamboo is immense. Bridges, boats, masts, rigging, agriculture, and other
implements and machinery; carts, baskets, troughs, pipes for conveying water,
pumps, fences for gardens and fields; tables, chairs, bedsteads, bedding, barrows,
fences, sacking, cordage, oakum, candle-wicks, whips, &c. are made of it.
Macerated in water it forms paper; the leaves are generally put round the tea
sent to Europe; the thick inspissated juice is a favourite medicine. It is said
to be indestructible by fire, to resist acids, and, by fusion with alkali, to form a
transparent glass. In Malabar, the bamboos are trained over iron arches, and
when they have assumed the curve of the mould, are used for roofs to palan-
quins, and sell at five or six hundred rupees a set.
BAMBOO HABIT. A Chinese contrivance, by which a person who cannot
swim, may easily keep himself above water. Four pieces of bamboo, about a
man's length, placed horizontally, and at right angles, in parallel pairs, and
tied firmly at the four corners, the opening being just sufficient to admit the
head and shoulders to get through, is then tied securely to the body of the
person using it.
BANDANNAS. A name given to a certain description of silk handker-
chiefs manufactured in the East Indies, the patterns of which generally consist
of square or circular spots, variously arranged upon a red, blue, or yellow
ground. An imitation of these handkerchiefs upon cotton, produced by first
dying fine calico of a brilliant Turkey red, and after discharging the colour from
those parts which, in the pattern, are white, by means of liquid chlorine, now
forms a considerable branch of the cotton manufacture of this country, and an
important article for exportation. A correct account of this process will be
found in the following description of the great bandanna gallery, in the Turkey
red manufactory of Messrs. Monteith & Co. of Glasgow, who obtained a patent
for the process. Their new arrangement of their hydrostatic presses in their
discharging gallery, was completed in 1818, under the direction of Mr. G.
Ridger, sen. manager of the works. It consists of sixteen of these engines,
beautifully constructed, placed in subdivisions of four; the spaces between each
set serving as passages to admit the workmen readily to the back of the press.
Each subdivision occupies 25 feet; hence the total length of the whole appa-
ratus is 100 feet. To each press is attached a pair of patterns in lead (or plates
as they are called) in which all those parts of the design which are to be white
are cut away, so as to form recesses in the plates. One of these plates is at-
tached to the upper block of the press, which block turns on a kind of universal
joint, so as to apply exactly to the under plate. The latter rest on the sill or
movable part of the press; when this is forced up, the two patterns close on
each other with the greatest nicety, by guide pins at the corners fitted with the
utmost care. The power which impels this great hydrostatic range, is placed
in a separate apartment, galled the machinery room. This machinery consists
of two cylinders of a peculiar construction, called the prime cylinder, having
pistons very accurately fitted to them. To each of these cylinders three small
force-pumps, worked by a steam engine, are connected. The piston of the
larger cylinder is 8 inches in diameter, and is loaded on the top with a weight
of 5 tons; it can rise through a space of 2 feet. The piston of the other cylinder
is only 1 inch in diameter, and is, likewise, loaded with 5 tons, and can also rise
through a space of 2 feet. The pistons being at their lowest point, water is in-
jected by the force-pumps into the prime cylinders, until the loaded pistons have
arrived at their highest points, in which state they are ready for working the
hydrostatic discharge presses; the water-pressure being conveyed from one apart-
ment to the other, through strong copper tubes of small calibre passing beneath
the floor. Two valves are attached to each press, one opening a communication
between the large prime cylinder and the press cylinder, and the other
between the small prime cylinder and the press. The function of the first is
simply to lift the under block of the press into contact with the upper block;
that of the second, to give the requisite compression to the cloth. A third
H 40 BANDAN NAS.
valve is attached to the press for the purpose of discharging the water from its
cylinder, when the press is to be relaxed in order to remove or draw through
the cloth. From twelve to fourteen pieces of cloth previously dyed Turkey
red, are stretched over each other as parallel as possible, by a particular
machine. These parallel layers are then wound round a wooden cylinder, or
drum, which is then placed at the back of the press. A portion of the four-
teen layers of cloth, equal to the area of the plates, is next drawn through
between them, by hooks attached to the two corners of the web. On opening
the valve connected with the 8-inch prime cylinder, the water enters the
press cylinder, and instantly lifts its lower block, so as to apply the under
plate with the cloth close to the upper one. This valve is then shut, and the
other is opened. The pressure of 5 tons in the 1-inch prime cylinder is now
brought to bear on the piston of the press, which is 8 inches diameter. The
effective force here, therefore, will be 5 tons × 8=320 tons, to compress the
cloth between the plates. The next step is to admit the bleaching or discharg—
ing liquor (aqueous chlorine, obtained by adding sulphuric acid to the solution
of chloride of lime) to the cloth. This liquor is contained in a large cistern in
an adjoining house, from which it is run at pleasure into small lead cisterns at-
tached to the presses; which cisterns have graduated index-tubes for regulating
the quantity of liquor according to the discharge pattern. The stop-cocks on
the pipes and cisterns containing this liquor, are all made of glass. From the
measure cistern the liquor is allowed to flow on to the surface of the upper plate,
and percolating through the portions of the cloth which lie under the open parts
of the pattern, it extracts the Turkey red dye. The liquor is finally conveyed
to the waste-pipe from a groove in the under block. As soon as chlorine liquor
has passed through, water is admitted in a similar manner to wash away the
remains of it; otherwise, on relaxing the pressure, the outline of the figure
discharged would become ragged. The passage of the discharge liquor, as well
as of the water, is occasionally aided by a pneumatic apparatus, or blowing
machine, consisting of a large gasometer, from which air, subjected to a moderate
pressure, is allowed to issue and act in the direction of the liquid in the folds. By
an occasional twist of the air stop-cock, the workman can also ensure the equal
distribution of the discharging liquor over the whole excavations in the upper
plate. When the demand for goods is pressing, the air apparatus is much em-
ployed, as it enables the workman to double his product. The time requisite
for completing the discharging process, in the first press, is sufficient to
enable the other three workmen to put the remaining fifteen presses in opera-
tion. The discharger proceeds now from press to press, admits the liquor, the
air, and the water; and is followed, at a proper interval, by the assistants, who
relax the presses, move forwards another square of the cloths, and then restore
the pressure. When the sixteenth press has been liquored, it is time to open
the first press. In this routine, about ten minutes are employed; that is, 224
handkerchiefs (16 × 14) are discharged in ten minutes. The whole cloth is
successively drawn forward to be treated in the º method. When the
cloth escapes from the press, it is passed between two rollers in front, from
which it falls into a trough of water placed below. It is finally carried off to
the washing and bleaching department, where the lustre both of the white and
the red is considerably heightened. By the above arrangement of presses,
1600 pieces of 12 yards each=19,200 yards are jaj into bandannas in
the space of ten hours, by the labour of four workmen. The following engraving
exhibits an elevation of one of the presses. a is the top of the entablature;
b b b cheeks of ditto, or pillars; c upper block for fastening the upper pattern
to ; d lower or movable block; e the cylinder; f the sole or base; g the water
trough for the discharged cloth to fall into ; h h tubes to admit the water; i
tube for the air; j cock to admit the liquor from the meter; k cistern, or liquor.
meter, having two glass tubes for indicating the quantity of liquor in the cistern;
! l glass stop-cocks for admitting the liquor into the cistern; o o stop-cocks for
admitting water; pp pattern plates; q q screws for setting the patterns parallel
to each other; the snuffs are perforated with a 3-inch drilſ; the lower frame has
pins corresponding with these perforations, so that the patterns are guided into
BANDANNAS. 14 I
exact correspondence with each other; r r rollers, which receive, and pull
through, the discharged cloth, from which it falls into the water trough; s stop-
cock for filling the trough with water; t t t waste tubes for water and liquor.
The patterns, or plates, which are put into the presses to determine the white
figures on the cloth, are made of lead, in the following way: A trellis frame of
ºr || |
N Y.
0
N
7.
11. Tziº |-25 H
cast iron, one inch thick, with turned-up edges, forming a trough rather larger
than the intended lead pattern, is used as the ground work. Into this trough is
put a lead plate, and firmly secured by screws passing from below. To the
edges of this lead plate, the borders of the piece of sheet lead which covers the
whole outer surface of the fame are soldered : thus a strong trough is formed,
about one inch deep. The upright border gives strength to the lead plate, and
serves to confine the liquor. A thin sheet of lead is now laid on the thick plate
of lead, and is soldered to it round the edges. Both sheets must be made very
smooth beforehand, by hammering them on a smooth stone table, and then
finishing them with a plane. The surface of the thin sheet (now attached) is
to be covered with drawing paper pasted down upon it, and upon this, the
#. is to be drawn. It is now ready for the cutter, who, in the first place,
xes down with brass pins all the parts of the pattern which are to be left
solid. He then j. with the little tools used generally by block cutters,
which are fitted to the different curvatures of the pattern, and cuts perpen-
dicularly quite through the thin sheet. The pieces thus detached are easily
lifted out, and thus the channels are formed which design the white figures on
the red cloth. At the bottom of the channels a sufficient number of small
perforations are made through the thicker sheet of lead, so that the discharging
T


142 BAR.K.
liquor may have free ingress and egress. Thus one plate is finished, from which
an impression is to be taken, by means of printers' ink, on the paper pasted on:
another plate; the impression is taken in the hydrostatic press. Each pair of
plates constitutes a set, which may be put into the presses, and removed at
pleasure.
BARILLA. A substance imported, in considerable quantities, from Spain,
and extensively used in soap-works, glass-works, and various other chemical
arts. It is obtained by the incineration of the salsola soda, a marine plant,
which is cultivated with great care in the neighbourhood of Alicant and Car-
thagena; that of Alicant is generally the most esteemed. An inferior species
of Barilla is also manufactured in many parts of North Britain, from the salsola
of Linnaeus, or common sea-wrack, and forms such an important article of
commerce, that it is said Lord Mac Donald, of the Isles, realizes 10,000l. a
year from his kelp shores alone, which his ancestors looked upon as of no value
whatever. The following account of the manufacture “on the farm of Strond,
in Harris,” possessed in tack by Mrs. Anne Campbell, is taken from the Trans-
actions of the Highland Society of Scotland. “1. The ware is cut off the rocks
with a common hook, similar to those used for reaping, but stronger, and having a
rougher edge. It is then landed on a clean spreading ground, and if any sand
or mud adhere to the weed, it is carefully washed before landing. The ware,
or weed, is then spread out every dry day, and made into small cocks at night;
and when it is found to be pretty dry, it is made into larger cocks, and left to
heat for six or eight days; after which, a dry day, with a good breeze of wind, is
selected for burning it; which operation is performed in kilns, constructed roughly
of middle-sized stones, the outside being covered with turf; the length of each kiln
is from 15 to 18 feet; breadth, 23 feet; and height, 2 feet. The process of
burning is as follows:—A small bundle of straw, or heather, is set on fire; the
driest part of the ware is placed over this, and gradually added until the flames
become general through the kiln; then the ware to be burnt is thrown in, little
by little, till the whole is reduced to ashes. If, however, it happens that the
day is too calm, or that the ware is not sufficiently dry, so that the ashes coo!
and cake into white crusts, the manufacturer stops burning any more until he
rakes all the ashes out of the kiln; he then commences burning again, and goes
on in this way until the whole is thoroughly burnt. The last process is the
raking or working of the ashes with an iron with a wooden handle, made for
the purpose, until the whole is brought into a vitrified state; the mass is after-
wards broken into pieces of about 2 cwt., in which state it is ready for shipment.
BARIUM. A metal discovered by Sir H. Davy, in the earth barytes, in
which it is combined with oxygen, thus constituting a metallic oxide. The fol-
lowing is the mode of obtaining it: take pure barytes, make it into a paste with
water, and place it on a plate of platina. Form a cavity in the middle of the
barytes, and in it drop a globule of mercury. Touch the globule with the nega-
tive wire, and the platina with the positive wire, of a voltaic battery of about
100 pairs of plates in good action. In a short time, an amalgam will be formed
consisting of mercury and barium. This amalgam must be introduced into a
bent glass tube, filled with the vapour of naphtha, and the end must then be
hermetically sealed; heat being applied to the received end in which the amalgam
lies, the mercury will distil over, leaving the barium, which is of a dark grey
colour, and of a lustre inferior to cast iron. Dr. Clarke asserts, that he obtained
metal by exposing pure barytes to the flame of the oxy-hydrogen blow-pipe,
but no one has since succeeded in the experiment, and it is generally believed
that the Doctor was mistaken, and that the globules which he formed, owed
their lustre and polish to the fusion the earth had undergone.
BAR.K. In Botany, the outer skin or covering of trees, the ingredients com-
posing which vary much in the different species, which are, accordingly, appli-
cable to various purposes of the arts. . Some are highly medicinal, as Jesuit's
bark; some are used for tanning leather, as the bark of the oak and Spanish
chesnut, &c.; some in dyeing, as the bark of alder and walnut trees; some
afford spices, as cinnamon, and cassia lignea; and others are applicable to divers
uses, as the bark of the cork tree. The Japanese make paper of the bark of a
BARKER'S MILL. 143
mulberry tree; and in Otaheite, a species of cloth is made from the hark of the
paper mulberry tree, of the bread-fruit tree, and of the cocoa-nut tree.
BARKER'S MILL. A simple and ingenious hydrostatic machine, invented
more than a century ago, by Dr. Barker, and forming one of the most simple
water mills ever constructed. It has been rarely introduced in practice, although
it has been warmly eulogized and recommended by most writers on the subject of
hydraulics. In the annexed engraving, which is a perspective view of the machine,
|
| |
i. |III s
ſ: ===sº
*
------- *-
==-- as
"- *-
I
; I
; : ====
: ; II; > <
F–Fº:
a b represents a vertical axis, moving on a pivot at b, which would be best made
of steel, and to run in a brass step let into a block of stone, as at c ; this axis
passes freely through the lower mill-stone d, and is then fixed to the upper
stone e. To the axis is also fixed the large vertical tube g, the upper part of
which is expanded into the shape of a funnel or basin, for receiving the water
from the mill-course or pipe i ; at the lower part g, this tube has an open com-
munication with the hollow horizontal arms h h, each of which has an
opening near its extremity on one side, and so adjusted by stop-cocks for
regulating the discharge, that the vertical tube shall always be kept full of
water, in order that the utmost force may be obtained, as a lateral pressure will
be exerted in all directions in the horizontal arms, proportionate to the altitude
of the column. Now this pressure being removed from the space forming the
area of the aperture of the arms, by the water being allowed to issue through
it, there will be an excess of pressure on the opposite side of the arm, in which
there is no pressure equal to the force with which the water would spout from
the aperture, were the machine fixed, and the water permitted to pass through
it. In the preceding form of Barker's mill, the length of the axis must always














144 BARLEY.
exceed in height the elevation of the pipe i, which in some cases might render
the execution of such a machine difficult. To remove this difficulty, it was
proposed by M. Mathon de la Cour, in Rozier's Journal de Physique, for August,
1775, to introduce the water from the mill course into the horizontal arms h h,
which are fixed to an upright spindle l, as represented in the annexed diagram,
and without any revolving vertical tube, as in the previously described arrange-
O
q
ment. The water will now obviously issue from the apertures at the extremities
of h h in the same manner as if it had been introduced at the top of the tube,
in the former figure; hence the spindle may be made as short as we please.
The practical difficulty, in this arrangement, is to give to the arms h h a motion
round the mouth of the feeding pipe, which enters the arms without any great
friction, or any considerable loss of water. In this form of the mill, o is the
reservoir; p the mill stones; l the vertical axis; q r s the feeding pipe, the
mouth of which enters the horizontal arm at s. In a machine of this kind,
constructed at Bourg Argental, the tubular arms h h were each 46 inches long,
and their inside diameter 3 inches; each of the orifices 1} inch diameter, and
the height of the head of water above the points of discharge was 21 feet.
Though the fall was so great, the consumption of water was small, since it was
supplied by a 2-inch pipe; and when the machine was not loaded, and had but
one orifice open, it made 115 turns in a minute. Thus a prodigious centrifugal
force is produced in the arms, and a corresponding velocity far exceeding that
of a simple fall of water with a pressure of 21 feet head. The machine, when
empty, weighed 80 lbs., and it was half supported by the upward pressure of
the water. It is to be regretted that no extensive and accurately conducted
experiments have been instituted to determine the comparative powers of this
machine, and that great difference exists in the opinions both of theoretical
writers and practical engineers upon the subject. L. Euler, J. Bernoulli, and
A. Euler, consider it to be the most powerful of all hydraulic machines. Whilst
the Abbé Bossut reckons the overshot-wheel as upon the whole superior to it,
Mr. P. Ewart says, that “the effect of this mill is much superior to that of an
under-shot water wheel, consuming the same quantity of water, but inferior to
that of an over-shot wheel, in which the water is applied to the best advantage;
but Mr. Waring makes the effect to be equal only to that of a good under-shot
wheel, when driven by an equal quantity of water falling from the same height.
BARKSTOVE is a kind of hot-house, containing a bed of tanners' spent bark,
mixed, according to circumstances, with a proportion of earth and other matters;
in which are placed the plants, in pots or otherwise. The bed is usually gently
heated from a flue underneath, which together with its disposition to ferment of
itself (when kept moist), forms a powerful stimulant to accelerate and perfect
the growth of exotic plants. \
BARLEY. A well known kind of grain, chiefly used in this country in the

BAROMETERS. 145
preparation of malt, for which see MALTING. The meal is also used in bread
and soups. Whiskey, gin, and other spirits, are distilled from it. The barley-
sugar of the shops is merely sugar boiled in barley-water to a consistency that
will cause it to solidify in the cold state; it is poured upon a stone slab, anointed
with oil of sweet almonds, rolled out into little cylinders, and twisted.
BARM, or YEAST, is a substance which separates under the form of a froth,
more or less viscid, from all the juices and infusions which experience the
vinous fermentation. It is commonly procured from the beer manufactories,
and is hence called the barm of beer. If left to itself for some days, in a close
vessel, at a temperature of from 55° to 70°, it is decomposed, and undergoes
the putrid fermentation. To prevent this decomposition, it is the custom, in
Paris, to evaporate it to a solid form, in which state it is sold under the name
of levure, which article, however, comprises not only yeast, but the bottoms
of the beer in the working-tun and store-casks. This is purchased by the yeast
merchants, the beer drained from it through sacks, and the remainder of the
beer washed out by putting the sacks in a stream of water; the solid matter
left in the sacks is then dried in the open air. The true yeast, or froth of the
beer, is also dried for use in the same manner, as the bakers in Paris prefer it in
a solid state. Dry levure ought to be yellow, brownish, or greyish white, by no
means black or bitter. It should not yield to pressure by the fingers, and be
equally dry throughout, so as to break with a smooth surface. When dissolved
in hot water, and a few drops of the solution are poured into boiling water,
they should immediately rise to the surface. See BEER, and BREAD.
BAROMETER. An instrument by which the pressure or elasticity of the
air is ascertained. It consists essentially of a glass tube, not less than 34 inches
in length, closed at one end. The tube is completely filled with mercury, and
then inverted in a cup or box of the same metal. By inverting the tube, a
portion of the mercury will fall out, but a column varying in height from 28 to
31 inches above the surface of the metal will still remain, and which, being
supported by the pressure of the air, will be an indication of its amount at the
time. The barometer has assumed a variety of forms, the construction of the
most important of which we shall endeavour to explain; but we deem it neces-
sary, previously, to enter a little more minutely into the nature and operation of
that form of the instrument to which we have just referred. The common baro-
meter was the discovery (for it can scarcely be called an invention) of Torricelli,
a disciple of the celebrated Galileo. It is, from this circumstance, frequently
called the Torricellian tube; and the vacuous space above the surface of the
mercury in the tube, is called the Torricellian vacuum. In the construction of
the barometer, the principal object to be attained is a perfect vacuum in the
upper part of the tube. To effect this, we must first make the tube perfectly
free from moisture by exposing it gradually to the heat of a charcoal fire. The
tube must have a bore sufficiently large to render the effect of capillary attraction
insensible. The mercury employed to fill the tube must be rendered as pure
as possible, by pressing it through the pores of chamois leather, and afterwards
distilling it. A small portion of the purified mercury may now be put into the
tube, and heat gradually applied to it, till the mercury boils. Another portion
may then be added, and boiled in a similar manner; and this process continued
till the tube is completely filled. By these means, the mercury itself will be
purged of any air it may have acquired, and the air which adheres to the sides
of the tube will also be effectually expelled. If the tube be now inverted into
a cup or other vessel of mercury, the barometer, as far as its construction is
concerned, will be complete. In the annexed cut, a c represents the barometric
tube inverted in its cup. The mercury has subsided to the point f : and the
next object is, to ascertain the precise length of the column from e to f. For
this purpose, a scale a b is attached to the barometer near the top. In the
ordinary use of this instrument as a weather-glass, the rise and fall of the mercury
seldom exceeds a range of 3 inches, the height of the column varying with
the atmospheric pressure from 28 to 31 inches. If, therefore, a scale of about
4 inches long, carefully graduated to tenths of an inch, be attached at the height
that accords with the number of inches we have mentioned, it will be sufficient to
[+6 BAROMETERS.
determine the ordinary changes of atmospheric pressure. There is,
however, one circumstance to which it is necessary to attend, in
measuring the height of the mercurial column. It will be seen,
that as the column fe falls, it will necessarily raise the level of the
fluid in the cistern; and contrariwise, when the column rises, it will
depress the level of the cistern. On this account, the initial point of
the scale is perpetually changing its position, and, consequently, the
numbers on the scale cannot indicate the true distance between the
surface of the mercury in the cistern and that of the supported column.
To obviate this inconvenience, the horizontal sectional area of the
cup is made considerably greater than a like section of the tube,
by means of which a considerable fall in the tube produces but an
inconsiderable alteration in the level of the fluid in the cup. For
example, if the diameter of the tube be 3 of an inch, and that of the
cup be 2 inches, the respective areas will be as # to 4, or as 1 to
64; hence a fall of 1 inch in the tube will cause a rise of ; of an
inch in the cup. In ordinary observations, this degree of accu-
racy would be sufficient; but in the nicer operations of science, a
greater degree of precision is essential; hence different contri-
vances have been employed for the purpose of ascertaining more
exactly the difference of levels. The most general mode of
effecting this object is to make the bottom of the cistern movable,
so as to be raised or depressed by means of a screw e. An ivory
index d may be attached to the top of the cup, and which being
finely pointed at the lower end, will serve to indicate a fixed level.
Before an observation is made with the barometer, the screw e is
turned until the surface is brought exactly to coincide with the point of the index, by
raising or depressing the bottom according as the surface was below or above that
point. By this means, the surface of the mercury always stands at the same level,
and hence the divisions on the scale a b will represent the actual changes in the
height of the barometric column. Having attained a method of fixing the initial
point of the scale, the next object to be attained is a means of reading offits indica-
tions with the utmost precision. In our description, we have supposed the scale
divided into tenths of an inch, but this is not sufficiently accurate for experimental
research. It would therefore be necessary to divide each of these tenths into hun-
dredths of an inch, and adapt a small microscope to the instrument, in order to
obtain the precise height of the column. The usual mode, however, of obtaining
these smaller subdivisions of the scale, is by means of a vernier, or small gra-
duated plate, which is movable by a screw, or otherwise, on Fig. 2.
se
the divided scale of the barometer. The principle of the ver-
nier will be seen by reference to the accompanying engraving.
Let ab represent a portion of the scale divided into tenths of
an inch ; let c d be the sliding scale, or vernier, equal in
length to 11 divisions on the principal scale, but divided
into only 10 equal parts. From this arrangement, it will be
seen that every division on the vernier will be the tenth part
of 11 tenths of an inch, or every division is equal to 11
hundredths of an inch, and, consequently, every division on
the vernier exceeds, by one hundredth of an inch, every
division on the principal scale. Suppose the vernier placed,
as in the diagram, so that its upper edge d may be exactly
even with the surface e of the mercury in the tube. If we
examine the principal scale, we shall perceive that the mer-
cury stands somewhat higher than 29 inches and 4 tenths.
If we now look at the vernier, we shall find that the divi-
sion 4, on its surface, coincides with a particular division on
the scale. Now, as we have seen that each division on the
vernier is one hundredth of an inch greater than one division
on the scale, it follows that the space from 29 up to the level
of the mercury, is 4 tenths and 4 hundredths of an inch,
–
kº-
#
249
:.
-
º
==





BAROMETERS.
and, consequently, the true altitude of the column
is 29 inches, 44 hundredths. In using the vernier,
considerable precision must be employed in making
its upper edge a tangent to the curved surface of the
mercury in the tube, and, consequently, its accuracy
will still depend upon the skilful manipulation of
the observer. To obviate this, and render the baro-
meter self-regulating, Mr. Christie, Secretary to
the London Mechanics' Institution, has invented
and constructed a barometer, in which, by means
of a float, the vernier is set at its proper height
by the rising or falling of the mercury itself.
The annexed sketch will show in what the
improvement consists. Here a b c represents a
glass barometer tube about 35 inches long, exclu-
sive of the part b c. It is not less than a quarter
of an inch diameter inside, and enlarged at the
top a to about two inches. On the surface of the
mercury, shown by the shading, rests a small glass
ball, or float d, supporting a slender steel wire, de
with its attached vernier f. This wire passes loosely
through a guide hole in the projection g to keep it
close to the scale of inches hi. In other respects,
the scale and vernier are similar to those of the
common barometer. The upper part of the en-
larged tube being vacuous, the mercury is pre-
vented from descending by the pressure of the
atmosphere on the surface at d, and as the pres-
sure increases, it will force down the mercury in
the part c 5 of the tube, and, consequently, cause
it to rise in the leg a b. As the surface at d falls,
the float carrying the vernier falls with it, and thus
the edge of the vernier being always kept at a
given distance from the surface of the mercury,
will indicate the precise amount of any changes
that may occur in atmospheric pressure.
In order to increase the extent of the baro-
metric changes, a contrivance is sometimes adopted,
called the diagonal barometer, which is represented
in Fig. 4. b c d is the glass tube bent at c, the
altitude of which is less than 28 inches; hence c b
includes the whole barometric range in the present
form, while a c is the range it would have were
the whole of the tube vertical. Now it is mani-
fest, that by decreasing the angle at c, so as to
bring b c nearer the horizontal position, we can
make its proportionate length to a c as great as we
please. Suppose b c so inclined that its length
shall be three times greater than a c, then every
rise or fall of 1 inch in a c would be equivalent
to a rise or fall of 3 inches in b c. The difficulty,
however, of observing the precise height of the
mercury in this arrangement, more than counter-
balances the advantage resulting from the extended
range, and this form is, therefore, seldom adopted.
The wheel barometer is another contrivance for
enlarging the scale, and rendering minute changes
more easily observed. This, which is the common
domestic barometer, is represented in Fig. 5, in which
d b is the longer leg, a b the shorter, in which the
*A
@ Eh
F-
Radze. E–
f ſº EE
Change 3—EH–
--
FEe-
Fa 37- H–
E-
Ø | Eli
| (*
d'A
b
Fig. 4.
|
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23
29
30
Cl,


# 48 BAROMETER.S.
changes of altitude occur: for as the diameter of the Fig. 5.
bulb d at the top is very large, compared with the d
diameter of the tube at c, a small fall in d will be º
equivalent to a considerable rise in the tube a b. Thus
the surface at c may rise 3 inches, and thereby
shorten to that amount the distance between the two
surfaces of the column, which is the true height sus-
tained by atmospheric pressure, without sensibly af-
fecting the level at d. At c there is an iron ball,
floating on the surface of the mercury, and partly
supported by means of a thread passing over the
pulley p, and carrying a small counterpoise at w. On -
the axis of the pulley, an index i is fastened, which / `s \
moving with it, branches the circumference of the Š)
circular plate, on which a scale is drawn, to repre- \
É
sent the rise or fall in inches; and also the terms
fair, change, rain, &c., which certain altitudes have S 2. =~ +
been improperly considered to indicate. In this §sº-º-º: ==
arrangement, it is manifest that as the column is R (l
C
any diminution of that pressure will cause the mer-
cury in the longer leg to fall, and that in the shorter
to rise. On the other hand, if the atmospheric
pressure increases, the mercury will rise in the
longer, and fall in the shorter, leg; but, as before 6.Nº
observed, the change of level will be scarcely per-
ceptible in the former, on account of the enlarged diameter of the upper part.
The changes, then, that occur in the shorter leg, may, without material error,
be considered the representatives of the changes that are continually occurring
in the atmosphere. Now it will be evident, on inspection, that as the ball c is
partly supported by the mercury, it will partake of its motion. If the pressure
of the air increase, the surface at c will be depressed, and as the iron ball must
sink with it, the thread to which it is attached will, at the same time, communicate
its motion to the pulley p, and through it, to the index, which will, consequently.
move from the right towards the left of the graduated circle. On the other
hand, if the atmospheric pressure decrease, the surface at c will rise, and, with
the assistance of the counterpoise wiforce up the iron ball, and, by this means,
turn the pulley and index in an opposite direction. There are two sources of
error in this instrument, that render it inferior to the simple vertical barometer.
These are, the pressure of the iron ball on the surface of the mercury, which
necessarily increases the height of the shorter column, and the friction of the
pulley. It is impossible entirely to annihilate these causes of error, and hence,
for philosophical purposes, the straight barometer is preferred.
The Syphon Barometer is an instrument used Fig. 6.
to ascertain the pressure of air in the partially
exhausted receiver of an air-pump. It consists 0.
of a tube bent as in the accompanying engrav- C ^
ing, Fig. 6. Each leg may be about 4 inches in
length, and one a b completely filled with puri-
fied mercury. When the instrument is con-
nected with the air-pump by means of the screw
at d, and the air partly exhausted, the mercury
in the leg a b will begin to fall, and, conse-
quently, rise in the branch c b ; every inch,
therefore, that it falls in a b, must be reckoned
equal to two inches in the straight barometer. TT 5
This instrument does not begin to act till the
air is reduced to about ; of its original density; d d
but this is no inconvenience, as its indications are seldom required till the
exha stion is nearly complete. If the leg a b be lengthened, and left open at the
supported by the air's pressure on the surface c, :
C




BAROMETERS. - 149
top, as in Fig. 7, this barometer becomes a useful appendage to the steam
engine, in ascertaining the pressure of steam within the boiler. When it is
attached to the boiler by the screw d, and the air or steam in the boiler has
the same elasticity as the external air, the mercury stands at the same height in
both legs; but as soon as the steam increases in elasticity, the mercury will be
depressed in the leg c b, and rise in a b, and the difference between the two
levels will be proportional to the difference between the external and internal
pressure. If the common barometer stands at 30 inches, and the difference of
level between the two surfaces is 6 inches, the elasticity of the steam will be
# or # greater than the pressure or elasticity of the atmosphere.
There are other forms of the barometer, but their comparative unimportance
renders it unnecessary to describe them here. We shall, therefore, proceed to
consider the most important purposes to which this instrument is applied.
The most immediate use of the barometer, for scientific purposes, is the ascer-
tainment of the amount and variation of atmospheric pressure. The fluctuations
in the pressure being observed in connexion with changes in the state of the
weather, a general correspondence is supposed to prevail between these effects.
The instrument has, from this circumstance, been called a weather glass. Rules
have been attempted to be established, by which the approaching state of the
weather may be predicted from the height of the mercury, and the words rain,
fair, changeable, &c. are engraved on the scales of common barometers. These
marks are, however, entitled to no attention, since it is the changes that occur
in the height, and not the absolute height, that indicates approaching changes
in the weather. The variation in the altitude of the barometer in a given place,
together with the corresponding changes of the weather, have been regularly
recorded for a considerable time; and it is by an exact comparison of these
results that general rules are to be found. At present, the best rules are liable
to some uncertainty at times. Those which have been considered least liable to
error are the following: 1. Generally, the rising of the mercury indicates fair
weather; its fall shows the approach of foul weather. 2. In sultry weather the
fall of the mercury indicates coming thunder. In winter, a rise indicates frost.
In frost, its fall indicates thaw, and its rise indicates snow. 3. Whatever change
of weather suddenly follows a change in the barometer, may be expected to last
but a short time. Thus, if fair weather follow immediately the rise of the mer-
cury, there will be very little of it; and in the same way, if foul weather follow
the fall of the mercury, it will last but a short time. 4. If fair weather con-
tinue for several days, during which the mercury continually falls, a long suc-
cession of foul weather will probably ensue; and again, if foul weather continue
for several days, while the mercury continually rises, a long succession of fair
weather will probably succeed. 5. A fluctuating and unsettled state in the mer-
curial column indicates changeable weather. The other important purpose to
which the barometer is applied, is the measurement of altitudes. If the atmo-
sphere were a liquid of nearly equal density, like water, the measurement of
heights by the barometer would be the simplest process imaginable : for we
should have then only to make one experiment to ascertain how much the mer-
cury would fall, in rising to the height of 100 feet for example, and then the fall
for 200 or 300 feet would, of course, be double or triple the former one. But
the density of air is well known to decrease as we ascend from the earth, so
that at the height of 3% miles, it is only one half its density on the surface of
the earth. From this it must be evident that if the mercury fall one-tenth of an
inch in rising through the height of 100 feet, we must rise through a greater
height to cause a fall of another tenth. The height of the surface of the atmo-
sphere above that of the earth is considered to be about 50 miles; and we have
already observed, that at the height of 34 miles the density is reduced to one-
half. Hence we should find, by ascending to the height of 33 miles in the
atmosphere, the mercury would stand at one-half the height of , another
barometer at the surface of the earth. If, however, the decrease of density
were affected by the height alone, the determination of altitudes would be com-
paratively easy, as a simple formula may be given, which would immediately
show the relation between the height and density. The circumstance that
U
150 BARREL.
interferes with barometric observations, is temperature, which affects them in
two ways. 1. Increase of temperature expands the mercury in the barometer,
and thereby causes the column to be longer than at lower temperatures. 2.
The air itself becomes expanded by heat; and hence the column becomes
lengthened without any increase in its absolute weight. It might be thought
that these effects were too trivial to influence sensibly the results of our obser-
vations; but it must be remembered, that as we ascend from the earth, the
temperature of the air rapidly decreases, so that at a certain height, dependent
on the latitude of the place, a freezing temperature constantly prevails.
Putting aside the effect of change of temperature, the simplest rule for deter-
mining heights is as follows:—Observe the height of the mercury at the
bottom and top of the altitude to be ascertained; take the logarithms of these
heights, and multiply their difference by 10,000, the product is the answer in
fathoms. Then suppose the mercury at the foot of a mountain to stand at 29.5
inches, and at its summit 26.4 inches, the calculation would be as follows:—
Lower barometer. . . 29.5 log. .469822
Upper ditto . . . . . 26.4 log. .421604
Difference .048.218
10000
482,180,000 Fathoms,
or, 2893 feet,
which is the altitude, supposing the temperature to be at 310 Fahr. If the
temperature differ from this, it must be observed at the upper and lower station,
and a mean of the two taken, by adding them together, and dividing the sum
by 2. If the mean thus obtained exceed 31°, the altitude before obtained must
be increased # for every degree of difference between them, and vice versa. If
we wish to correct the other error arising from the expansion or contraction of the
mercury in the barometer, we must observe the temperature of the mercury at the
upper and lower station; then the altitude of the lower one must be increased, or
the higher one diminished, in part for each degree of difference between their
temperatures. To those who are unaccustomed to the use of logarithms, the fol-
lowing rule may be preferred:—Take the sum and difference of the upper and
lower barometric heights, and divide one by the other; multiply the quotient by
55000, and it will then answer in feet for a temperature of 550. Suppose, as
before, the height at the lower station to be 29.5, and at the upper, 26.4 then
29.5—26.4
—— — = 0554
29.5 + 26.4
And .0554 × 5500 = 3047 feet.
This result, it will be seen, exceeds the other by 154 feet; it is not so exact,
but, in many cases, it may serve to furnish a tolerable approximation, when
logarithmic tables are not at hand. The corrections for temperature may be
applied as in the other formula.
BAROSCOPE. An instrument for shewing the weight of the atmosphere,
frequently confounded with the Barometer: the former, however, only proves
that the atmosphere has weight; while the latter determines its true quantity.
BARREL. This article, as made by coopers, is too well known to need a de-
scription; but the air and water-tight metallic barrels employed in the British navy
for preserving provisions, from their peculiarity of structure and utility, require a
§. in this work. Those which we shall describe are of the most improved
ind, and were patented by the late Mr. Robert Dickenson, of the Eagle Foundry,
Southwark. These barrels are made of wrought iron, of a cylindrical form,
with a seam, soldered or rivetted, in the usual way. To strengthen the figure,
and adapt it for the reception of the heads, a strong iron hoop is rivetted to
each end of the cylinder. These hoops are prepared at the iron works, by
rolling them into the form of a rebate, shown in section at b, Fig. 1. By this
diagram it is also shown that the hoop is fastened with its thickest part against
the side of the barrel a, about an inch below the extreme edge of the same;
thus forming a deep groove between the sides of the barrel, and the thinnest
BARREL. 151
part of the rebated hoop, for the reception of the flange of the head e, which
* * * * **** e 4-1- :-l. ~-- ~£ al- - -------! --- ?----- ~! 2 += +... = +3,...}, i
appears to be made by bending thc periphery of the Circuiāī iſſoil Piave vu a “gut
iſiºnal||
Fig. 1. *==}} #
--
angle with its plane. Previous to the driving down of this head, a sort of pack-
ing, composed of hemp-bands, or currier's leather-shavings, is to be rammed
into the groove, so as effectually to exclude both air and moisture. To secure
the bottom head in its place, the thin projecting edge of the hoop is to be ham-
mered down upon the bottom, and over this is to be rivetted a flat iron ring, to
serve the purpose of the ordinary chimes of barrels, the exterior edge of which
should extend a little beyond the periphery of the cylinder, to defend the sides
of the barrel in rolling it. The upper head of the barrel is so constructed as to
be removable at pleasure, the hoop which circumscribes it being the same as
that on the bottom; but, instead of being hammered down, it is left erect, as
shown at Fig. 2. The head is placed also within a similar groove, and is fastened
down by means of a number of latch-bolts. These latch-bolts are attached to
the head, or movable cover, by means of a pivot at one end, upon which they
turn, and are driven sideways into long slots made through the projecting hoop,
which slots are not made in a parallel line with the top of the cask, but aslant,
so that when the latch-bolts are driven into them by a hammer, they draw the
flanged head into the deep groove, which, being previously packed in the
manner before-mentioned, makes the junction perfectly air and water-tight.
This kind of cover, likewise, admits of its being very readily removed, by
driving back the latch-bolts with a hammer; and the inconvenience formerly
experienced in the smallness of the apertures in air-tight vessels, is herein com-
pletely removed, the opening being as wide as the barrel itself, so that larger
matters may be stowed in it, and the packing, and removing of the contents
greatly facilitated. Metal casks, heretofore employed for similar purposes, were
usually coated with paint to prevent oxidation, and render them water-tight,
which was found to communicate a bad flavour to the flour, biscuit, or other
materials which they contained. To remedy this inconvenience, the patentee
coats the barrels, both inside and outside, with any of the well-known water-
proof compositions, which, while they effectually prevent oxidation, will not
communicate any unpleasant taint to the articles of food, even in the hottest
climates. The patentee has selected the following:—To 1 pound of caoutchouc
(Indian rubber) add 8 oz. of black resin, and 2 oz. of Venice turpentine; let
the caoutchouc be cut into small pieces, and expose the mixture to a heat of
1600 for the space of 24 or 36 hours. When dissolved, it is to be spread upon
canvass, or other fibrous material, and then passed between cylindrical rollers
to give it an even consistency. With this material the barnels are to be coated
both within and without, except in the case of dry goods, such as biscuits,
flour, &c., when the coating of the exterior alone is considered sufficient, and
the interior surface of the iron may be bronzed in the came manner as gun-
barrels. For oils, tar, varnish, &c. the insides of the barrels have no coating,
those materials being, of themselves, preservatives against oxidation. In some
cases of dry goods, the inside may be coated with the thinnest and cheapest
woven matérial, or even paper; and these may be attached, by any cheap kind
of cement, that will effectually exclude the air and moisture.





152 BARROW.
BARROW. A machine for carrying loads by manual labour. Barrows
are of two classes: hand-barrows, and wheel-barrows. Hand barrows consist
merely of a small platform attached to two poles projecting equally from each
end, and carried by two men in the manner of a sedan chair. Wheel-barrows
are made of various
forms, widely dif-
fering from each
other, to suit the
particular work for
which they are
intended, as ex- |\
cavator's barrows,
brickmaker's bar-
rows, &c., but all
of them are con-
structed with a single wheel in front, and two
handles behind. Barrows are an advantageous
mode of employing the power of men; accord-
ing to Coulumb, a man with a barrow will do
half as much more work as he can do with a
hod. The longer the arms of the barrow, the
less is the labour of wheeling it. A great
improvement has been made in wheel-barrows,
by the addition of two long leaf-springs, in the
outer end of which the pivot of the wheel
turns, instead of being carried by stiff inflexible
arms, as heretofore. In the construction of
docks, canals, embankments, &c., one very
great portion of the labour consists in raising
the earth from a lower to a higher level, and
this is mostly done by barrows; but the common
mode of barrowing, by which one man is drawn
almost vertically up an inclined plane, along with
a loaded barrow, whilst another man descends a
similar plane with an empty barrow, is extremely
dangerous, many men having lost their lives, or
having been seriously injured by it. In the
following plan, invented by Mr. Matthews, and
which has been rewarded by the Society of
Arts, by an honorary gold medal, these evils
are entirely avoided, as the barrows are alter-
nately drawn up and let down without any
workman accompanying them. a a is a plank
10 or 11 inches wide, laid at a small angle suf-
ficient to keep the barrow-wheel in contact
with it, and two strips b b are spiked to the
edge of the plank, so as to form a groove for
the wheel of the barrow to run in; two pieces |
|
of quartering, or small spars c c, are fixed on
each side, at a proper distance, to guide the
handle, by which the barrow is kept in a ||'''{
proper position against the plank upon which -
the wheel runs; about 10 or 15 feet from the y
- W]
top of the plank, ... • •.
.." . rº. º, Nºy4.JNº j) l,
where the load-
ed barrow is to - ST
land, a pulley cº
d is fixed to a
pole e, through ſº-º-Sº / iſºſ –-a” 7

BASKET. , 153
which the rope, or chain, is passed down to the barrow; to the end of the rope
is fastened a hook, which goes into an eye f fixed upon the point of the barrow.
A pair of slings are slid upon the handles of the barrow, previously fastened
upon the rope at a proper distance, to keep the barrow in a right position to be
drawn up the plane, or plank, which is when the handles of the barrow are a
little below the horizontal line with the wheel of the barrow while running up
the plank. ... The rope, after passing over a pulley d, passes through another
leading pulley g, at a proper height to suit the draft of a horse, and is con-
nected to a similar apparatus at another inclined plane, situated at a distance
from the former, somewhat exceeding the length of the planes on which the
barrows run. A horse is attached by a rope to the middle of the horizontal
part of the rope g g, and alternately traversing between the two stations, raises
a loaded barrow at one station, or plane, whilst an empty one descends at the
other, unaccompanied by a man. The pulley d is elevated so high as to let the
rope from the barrow clear the bank, and yet incline so much inward that the
barrow clears the bank as it swings in, and lands itself as shown by the dotted
lines. The man has only to fix the ropes to the empty barrow, and wheel the
full one away.
BARYTES. An alkaline earth, most commonly found combined with sul-
phuric acid, forming sulphate of barytes, or heavy spar. The experiments of
Sir H. Davy show barytes to be an oxide of a metal to which he gave the
name of Barium, which see. See also CHEMISTRY.
BASALTES, in Natural History, a heavy hard stone, most commonly black,
or greenish, consisting of prismatic crystals, the number of whose sides is uncer-
tain. It is distributed over the whole world, but nowhere exists in greater
variety than in Scotland. A celebrated range of columnar basalt exists in
Ireland, and is known by the name of the Giant's Causeway. It consists of
three piers of three columns, which extend several hundred feet into the sea.
These columns are, for the most part, hexagonal, and fit very accurately
together, but, generally not adherent to each other, although water cannot
penetrate between them. Basaltes, when calcined and pulverized, forms a
good substitute for puzzolana, in the composition of hydraulic cement, having
the property of hardening under water; and it has also been converted into
glass, from which wine bottles have been manufactured.
BASE is a term usually applied to the lowest part of any thing; thus, in
Geometry, it is the lowest side of the perimeter of a figure; in Architecture,
the lowest part of a column, or pedestal ; in Building, the lowest apartment is
also called the basement.
BASE, in Surveying, is a line measured with the greatest exactness, on which
a series of triangles are constructed, in order to determine the position of objects
and places.
BASE, in Chemistry. Any body which is dissolved by another body, which it
receives and fixes, and with which it forms a compound, may be called the base
of that compound. Thus, for example, the base of neutral salts, are the alka-
line, earthy, and metallic matters, which are saturated by the several acids, and
form, with them, these neutral salts.
BASKET. A fabrication woven of straw, rushes, canes, and other elastic
materials; but, in this country, principally of willow; which last, according to
their growth, are called osiers and sallows. Osiers for white work are deprived
of their bark by an instrument called the braker, and afterwards are cleaned
by a common knife. They are then exposed to the sun and air in order to dry
them thoroughly; after which they are housed, and kept carefully from mois-
ture, which, if attended to, will preserve them for years. The same precautions
against moisture are necessary for preserving osiers with their bark on. When
these osiers are intended to be used, they are soaked for a few days, according
to their age and dryness. Osiers deprived of their bark are assorted by the
basket-maker into large and small rods, according to the work for which they
are intended; the larger ones forming the slat and skeleton of the basket, and
the smaller ones for weaving the bottom and sides. For common work, such as
clothes-baskets, market-baskets, &c., the rods are used whole; but, for the finer
154 BATH.
work, as table-mats, fruit and work baskets, and the like, the osiers are divided
into four parts, lengthways, which are called splits, and these are afterwards
reduced to various degrees of fineness, when they are called skeins. . The
method of making a basket of the ordinary kind is as follows:—The workman
having cut off the large ends of as many osiers as he deems necessary, and of
a length somewhat more than the width of the bottom, lays them on the floor
in pairs, all ranging the same way; he then places on them two of the longest
osiers, with their largest ends towards him, crossing the direction of the former;
on the large ends of the two long osiers he places his foot, weaving each alter-
nately under and over the short ends, which confines them in their places, and
forms what is called the slat, or slate, which is the foundation of the basket.
He next takes the long end of one of the two rods, and proceeds to weave it
under and over the pairs of short ends all round the bottom, until he has wove
the whole of it; this is, likewise, done with the remaining osier, and after this
is exhausted, other long osiers are wove in, until the bottom is of a size sufficient
for the intended basket. The workman next proceeds to sharpen the ends of as
many long and stout osiers as may be necessary to form the ribs, or skeleton of
the basket; the sharpened ends are planted, or forced, between the rods of the
bottom, and are turned up in the direction of the sides, and the other rods are
woven in and out, between each of the uprights, until the basket is raised to
the intended height. To finish the edge, or brim of the basket, the ends of the
ribs, which are now standing up perpendicularly, are turned down over each
other in a manner easily understood by inspecting a basket, although difficult
to describe. There remains only to add the handle; this is done by planting
or forcing down close to each other, between the weaving of the sides, two or
three osiers, cut to a proper length; when in their place, a hole is made through
them, about two inches from the brim, into which a pin is put, to prevent their
being drawn out; they are then covered, or bound together with skeins, some-
times of various colours, forming different kinds of platting on the handle.
Basket-work is well adapted to many other purposes than those to which it is
at present applied, as it combines, in an eminent degree, the three qualities of
strength, lightness, and elasticity.
BASSOON, a musical wind instrument, blown with a reed, furnished with
eleven holes, and used as a bass to hautboys, flutes, &c.
BASSORINE. A name given to a substance which is extracted from the gum
resins, by successively treating them with water, alcohol, and ether. The bassorine
being insoluble in these liquids, remains mixed merely with the woody particles,
from which it is easy to separate it by repeated washings and decantations,
because one of its properties is to swell extremely in the water, and to become
very buoyant. This substance swells up in cold as well as boiling water, without
any of its parts dissolving. It is soluble, however, almost completely by the
aid of heat in water sharpened with nitric or muriatic acid.
BATH. A receptacle of water in which to plunge, wash, or bathe the body.
The practice of bathing, although not so common in this country as on the
continent, is daily becoming more general; and, in most large towns, there are
E. establishments, where, at a very short notice, warm, cold, and vapour
aths, either plain, saline, or medicated, may be had. From the beneficial
effects of hot baths, in sudden cases of inflammation of the bowels, and of
cholera, portable baths, of various kinds, have been constructed, by means of
which a hot bath may be speedily prepared in a sick chamber; and the appa-
ratus occupying but little space, can be easily stowed away when not in use.
The annexed cut represents a simple and effectual apparatus of this description,
invented by Mr. Benham, of Wigmore Street, Cavendish Square. a represents
the ordinary bath filled with water to the proper height; b a furnace for heating
the water; and c a fender to keep in the fuel and ashes; at the end d e the
bath has a double case, at top and bottom of which there are apertures com-
municating with a double-cased boiler that entirely surrounds the fire. The
water thus heated naturally ascends and enters the bath at e, while the cold
Water to supply its place enters the boiler at d ; thus a continued circulation of
the water is effected by this arrangement, so as to heat it very quickly, and by
BATTERING RAM. 155
a small fire, more conveniently and agreeably situated, than if placed under the
bath as usual; f is a pump, the lower end of which dips into a small well at
the bottom of the bath for discharging the water; g is a small wrought-iron flue;
the whole runs upon castors.
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In Mr. Hick's portable baths, a broad shallow flue of metal is constructed
underneath the bath, and in the flue is ignited a determinate quantity of the
oil of turpentine, or other inflammable liquid, supplied from a reservoir above,
in the side of the bath, and regulated by a stop-cock. The vapour arising from
the combustion is carried off by means of a tube, into the apartment in which
the bath is placed. By a slight modification of the foregoing plan, the patentee
purposes to employ the flame of condensed inflammable gas for heating the
water rapidly; and in the water may be infused herbs, or other medicaments,
for patients who may be labouring under cutaneous diseases. By these arrange-
ments, a portable warm bath is prepared in a few minutes.
BATHS in Chemistry, a contrivance for subjecting different substances
either to a steady heat, not liable to sudden fluctuations, or to a temperature
which shall never exceed the boiling point of water. In the first case, the
vessel containing the substance to be heated is imbedded in a vessel containing
sand, or other slow conductor of caloric, and set in a furnace, and this is called
a sand bath; but if it is desired that the temperature shall not exceed 2129,
water is substitute for sand, and this is called a water-bath. A familiar example
of a water-bath is the common ------—-
glue-pot, which consists simply ...~"
of a vessel containing water, in
which is immersed another ves-
sel containing the glue. Mr.
Vazie recently patented culi-
nary vessels on the same prin-
ciple, an illustration of which is
subjoined; a being the external
vessel containing water; b the
internal vessel containing the
food; and c the cover. The
principle of this method of limit-
ing the temperature has received
a more extensive application, by
Messrs. Beale and Porter, who
have obtained a patent for em-
ploying, as a heating medium,
various substances, which rise in vapour at different degrees of the thermometric
scale, some exceeding, and others falling, below the boiling point of water, such
as alcohol, ether, naphtha, turpentine, and various essential oils. Under the
head BoILER will be found a description of an apparatus upon this principle.
BATTERING RAM. An ancient military engine, used for destroying the
walls of fortified places, but which, since the invention of gunpowder, is no










156 BEAMS.
longer used for that purpose, as, by means of cannon, the attack can be made
from a much greater distance; but machines of this description are still some-
times employed in taking down old and massive walls. The battering rams of
the ancients were of two kinds; the first consisted merely of a heavy beam,
with a head of iron, which the soldiers bore in their arms, and assailed the
walls by main strength. The second sort was much more powerful and effective.
In these the beam was suspended by chains from a frame; the centre of gravity
of the mass of the beam being pulled out of the perpendicular by ropes, they
were suddenly let go, causing the head of the ram to strike the wall with a
force proportional to the weight of the mass, and the space through which it
moved. Some of these instruments were of enormous dimensions, and of
immense power. That of Vespasian is said to have been 120 feet long, and to
have weighed 100,000 lbs. The effect of some of these instruments, was much
superior to any we can produce by our breaching cannon; for if the weight of a
battering ram, moving with a velocity of 10 feet in a second, were no more
than 170 times that of a cannon ball, moving at the rate of 1700 feet in a
second, the momenta of both forces would be equal; but as the weight of these
ancient machines was much greater than 170 times that of our heaviest cannon
balls, their momentum, or impetus, to overturn walls, and demolish buildings,
was much superior to that exerted by our modern artillery.
BEAM, in Building, a piece of timber resting upon walls, and used to sup-
port the floors or fronts of houses, to suspend weights from, &c. The strength
of beams to each other is inversely as the length, and directly as the breadth
and the square of their depth; their depth, therefore, is generally made greater
than their breadth, as, by this means, greater strength may be obtained with
less material; thus diminishing both the weight and the cost. Beams are
variously named, according to the situations they occupy in a building. A tie-
beam is a horizontal beam, extending from the opposite walls of a building, and
having notches near the extremities against which the lower ends of the prin-
cipal rafters of the roof abut, by which means the thrust of the rafters is exerted
against the tie-beam, instead of acting against the walls. A girder is a stout
beam, extending from one side of a building to the opposite one, and used to
carry the joists: when the distance between the walls is great, it at the same
time serves as a tie to the walls. A bressummer is a beam used to support a
portion of a building above a considerable opening similar to a lintel over a
door-way. When a beam projects from a wall, the outer end being unsupported,
it is termed a cantilever. In cases where the distance between the points of
support is great, and the load to be sustained by a beam is considerable, instead
of a beam formed of one piece, a frame of timber, called a truss, is employed,
which, in its simplest form, consists of two inclined beams, abutting against
notches in a horizontal beam near its extremities; and the upper ends of the
beams meeting in a point upon which the load rests, by which means the pres-
sure is transferred from the centre of the beam, to the part of it which is over
the points of support, and the stress upon the beam is changed from a transverse
strain to a tensile strain, operating in the direction of the fibres. Roofs and centres
of bridges are specimens of trusses, and are framed upon the same principle,
although more complex in the form. The methods of forming trusses are very
Fig. 1.
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varied, depending partly upon the uses for which they are intended; the following
description of a very neat, simple, and effectual method of constructing rafters for


















BEAMS.
a nearly flat roof invented by Mr. Smart, of the Ordnance Wharf, West-
minster Bridge, is an extract taken from the inventor's communication
to the Society of Arts. “ I take a square spar of the usual size for a rafter,
and, by means of a circularsaw, make an incision in it as shown at bb, Fig. 1
page i56. I then make the cut c at right angles to the former, and equi-
distant from the two ends; lastly, I make the two cuts d d, taking out a
thin wedge from each place. The two pieces c d are then to be gently
raised up, till they form an angle of 10° or 12°, with the piece b b,
and are secured in their place by the insertion of a key-wedge e of
seasoned oak, as represented at Fig. 2. It is obvious that a weight
pressing on the key-wedge of this rafter (the ends being properly sup-
ported), will be sustained till either the fibres of the wood forming
the string are drawn asunder, or till the lateral cohesion of the wood
forming the butt-ends of the rafters be destroyed; at the same time
there is no lateral pressure on the wall.” The above rafter is com-
monly known by the name of the “Bow and String Rafter.”
Another rafter upon the same principle, by the inventor of the fore-
going, is shown in the margin. The rafter, which is 56 feet between
the bearings, is made out of a scantling 10 inches by 4. An incision
is made by a circular saw, from the middle nearly to each end; a
transverse cut is then made at a, through the middle of the upper
part of it, and at each end b b of the incision, a transverse piece, of a
wedge shape, is cut out, reaching nearly to the longitudinal incision,
but not so near as to separate the parts. Short pieces of wood are
then inserted between the upper and under part of the rafter, and the
whole are secured by iron straps. It appears that Mr. Smart was led
to the foregoing method of forming rafters, by the following experi-
ment, which he made for the purpose of ascertaining whether the H
strength of a beam is increased in the proportion of three to two, as
stated by Belidor, by fastening its ends so as to prevent their
approach when loaded in the middle. He placed a lath, an eighth of
an inch thick, in a strong frame, as shown by the annexed cut, which
broke with a load of - •
iiibs placedonitºmid Lh th-
die. Henext tookalath
of the same wood, and
fixed it firmly at the ---1C - & E---
ends, by means of the 5L & II &
projecting pieces b b
and the wedges c c, and
ascertained that it
would sustain, by this [T.
arrangement, a load of *
270 lbs. whence it appears that the strength of the lath was increased
nearly 25 times, by merely securing it well at the ends. º
The following figure represents a trussed girder of wrought iron,
similar in construction to the foregoing. This girder is made by
welding an arched bar of wrought iron to a longer straight bar, and
then turning the ends of this latter either up or down, as may be most
convenient for the particular use to which the girder is to be applied.
t t are the places where the bars are welded together that compose
the girder; u u the ends of the straight bar turned either up or
down. The arch is prevented from buckling, when the weight presses
upon it, by means of blocks of well-seasoned wood, inserted at inter-
vals between the two bars, and secured in their places by the iron Straps
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158 BEAMS.
v v. Beams of wrought irch made in this way will, in Mr. Smart's opinion,
support a weight so much greater than cast iron ones of equal dimensions,
that they may be made of any given strength at half the cost of equivalent
beams of cast iron.
The cut on the left represents one of the iron girders employed in building the
London University. The whole length is 36 feet, and cast in one piece; it
rises in the middle about 25 inches, and is provided with a wrought iron tie or
sm, circular bolt of about 3 inches diameter, which passes
g- through apertures in the series of projecting pieces
shown, and is strongly screwed up at the ends c c.
On each side of the girder are bolted wooden scant-
lings, into which the joists are framed.
Fig. 1 represents a trussed girder, invented by
Mr. J. Conder, on the principle of suspension; and
Figs. 2, 3, 4, 5, represent separate parts of the plan of
trussing, and the same ietters refer to similar parts in
all the figures. The girder a a Fig. 1 is furnished with
cast iron plates, turned down at right angles, to extend
over its ends. These end plates have on their upper
surfaces circular hooked projections, shown in elevation
by Fig. 2, and in plan by Fig. 3. The use of these
Fig. 2. Fig. 3.
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iron, bent in the middle to correspond and fit into the
hooked projections, as represented by 5 Fig. 3. The
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BEA MS, lă9
iron, and are secured by screwing thereon nuts, as shown at Fig. 4. Between
the pieces d d and the lower side of the girder are placed prisin-shaped biocks
of oak c c, shown in section by Fig. 5, which vary in size according to the depth
of the roof or floor which the girder is intended to support. Below the middle
of the girder, and parallel thereto, extends a single rod f equal in strength to a
double rode e, this rod passes through the middle of the cross pieces d d, and
is secured by nuts screwed on its ends, as represented by Fig. 4. All the parts
of the truss may be brought to any required tension, and the girder made to
camber simply by screwing up one of the nuts on the rod f. A somewhat
simpler plan is represented in the following figure, whilst it possesses the same
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advantages as to strength and durability. The girder d to be trussed, is divided
longitudinally into two flitches, and between them is introduced a single rod of
iron e, the ends of which pass through the kneed plates b b, and are then
secured by screwed nuts; the ends of the flitch are bevelled off at right angles,
to the direction of the trussed rod. Beneath the girder are placed two triangular
blocks d d, proportionate to the strength required. The two flitches are kept
apart the thickness of the truss rod by the introduction of slips of wood between
them, and kept in their places by straps at e e e e.
Mr. Renton's arrangement of the suspension trussed girder is shown in the figures
beneath. Fig. 1 is an elevation of the truss, with one of the flitches removed
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160 BEAMS,
to show the iron work; and Fig. 2 is a section of the girder, a a the two sus-
pension links, connected with the two tie links b b by bolts and keys, through
the cast iron saddle pieces d d. The upper
ends are united to the abutment pieces
c c by bolts passing through them; the
beam is adjusted to its bearing, or cam-
bered, if necessary, by the folding wedges
(seen at e e Fig. 2) at the back of the
saddle pieces, which it may be found ne—
cessary to steady sideways by blockings
spiked to the beams. Figs. 3 and 4, eleva-
tion and plan of another mode of connect-
ing the tie links and adjusting them by
wedges. Fig. 5, anotherform of link, which
may be used, instead of the double barlink.
The subjoined figures represent one
of the girders employed at Messrs. Nichol-
son's distillery, to support a liquor back
containing 19000 gallons, which, when
full, weighs nearly 100 tons. Fig. 1
is the elevation of the girder, with one
of the flitches removed. Fig. 2 a plan of
the truss, a a a Fig. 1 are three strong
plates of cast iron, forming a sort of arch,
of which the centre piece may be con-
sidered the key-stone, and b b cast iron
plates, resting on the wall, as the abut-
ments. c c cast iron blocks, in which the
upper ends of the two side plates a a, and
the ends of the middle plate are lodged;
d d blocks of cast iron, which are screwed
up against the under side of the girder,
by nuts on the end of the screw-bolts
passing through the blocks c c. e is one
of two wrought-iron tie bars, passing
through the blocks d d and b b, and se-
cured by nuts at the ends e, and which
ends, as a further security, are chained.
The blocks b b have protuberances f f
which are let into the bearing timbers g
on the walls h. The ends f b of the
blocks incline outwards about 10 degrees,
on which account the flitches of the
girder cannot slip down, but must press
at the angle b, as must also the points
between b f of the plates a a, when the
weight presses down the queens by the
part of the girder bearing on their
shoulder or on the blocks d.d, thus giving
the whole weight to the bars e in the
direction of their length, just as if the
weight were suspended vertically from
those bars, or nearly so, the girder being
merely a rest for the base of the back.
'ig. 3 is the end, with the girder trussed
on; 4 is the end view of the blocks d d,
through which the tie bars pass; 5 a
section of the inner part of the end
block, when trussed; 6 is one of the iron braces which saddle over the flitches,
to keep them to at top ; and 7 is one of the pieces of oak which fit into the

HEAMS. ſ 61
apertures between the flitches to preserve the bearing. The bars e are 23 inches
in diameter, or upwards of 3% inches area.
We shall conclude this article with a description of a trussed girder proposed
by Mr. Gutteridge, and which we insert rather for the novelty
of the contrivance, than for any great merit which we can
discover in it, a is a beam of wood or girder to be trussed,
lodging on the walls h, , bg b a wrought iron plate or bar lying
on the beam, and attached to iron levers b c d by pivots at b.
These levers are attached to the ends of the beam by iron plates
i, which are fulcra, c being the centre. To the lower extremity
or pivots of the arm c d is attached a bar of iron l at each end,
and these are connected by pivots at ef to a similar bar m, and
are kept below the beam by cast iron blocks k. The object of
this construction is to cause any weight laid upon the beam at
g to counteract its own tendency to bend the beam, by its in-
creasing the tension of the suspension rods l m l, which would
cause the blocks k k to rise; but the weight of any load is
made to increase the tension of the tie-bar by much simpler
means in some of the trusses previously described, as in Smart's
bow and string rafter, or in the girders at Mr. Nicholson's
distillery.
BEDSTEAD. The forms of bedsteads are so numerous,
and at the same time, so well known, as to render description at
once tedious and unnecessary; we shall, therefore, merely notice
a bedstead designed especially for the use of invalids. It is the
invention of Mr. Rawlins, of Pentonville, and is named by him
the Patent Invalid Bedstead. In the engraving in the next page,
which is a perspective representation of this invention, A repre- $ §
sents the bedstead; B, swing frame, showing the head and foot
frames raised; C, rising head frame; D, rising foot frame; E
in the figures underneath shows the elevation of the knee-joint;
F, folding side frame. The patient lies on the mattress on the «d
swing-frame, which may rest on the mattress beneath; or, if
desirable to be softer, on a bed; and, for the convenience of per-
forming the offices of nature with cleanliness and comfort, the
swing-frame is raised up by turning the handles at the head and
foot of the bedstead (one, or both, as the occasion may require),
so as to admit a bed-pan to be placed beneath a circular hole
in the mattress (the cushion which fastens in underneath with
a buckle and strap having been previously removed). By
raising the swing frame higher, the bed beneath can be shaken
up without inconvenience to the patient. . . In asthmatic and
other complaints, where a difficulty of breathing is experienced, S
the rising head frame may be elevated so as to give the utmost
relief the nature of the disorder will admit of. As persons long
confined to bed grow weary of lying in one position, a change
may be readily obtained by the aid of the attendants, and, in
some cases without it. If, for example, it is wished to raise the
feet, the attendant raises the rising foot frame by the hand hole
in the foot board, and the swing bracket fixed beneath drops
into the racks cut on each side of the swing frame, and supports
it at the desired elevation; again, if the knees require to be
raised, the frame is raised as shown in the figure E, the ends of the frame
dropping into the rack before-mentioned; if it is wished to raise and support
the body on one side, the folding frame being introduced between the mattress
and the swing frame, and the upper leaf of it raised, the patient is quietly
turned on his side, and supported in that position by the bracket dropping into
the racks cut in the lower leaf as shown in the figure F; in short, the appa-
ratus may be arranged to suit any position which may be desired; and for the
accommodation it affords to the invalid, and for the facility with which the




162 BEEFA IV E.
requisite changes are effected, we think this apparatus superior to any invention
of the kind which has come under our notice.
BEEHIV.E. An artificial habitation for bees, usually constructed of straw. This
description of hive is so well known, that we shall i; remark upon one or two
essential points. First, care should be taken to have the hive made of clean
and good straw, and of suitable thickness; and, secondly, it should be well
sheltered from cold winds, and rains, for if once the wet penetrates the hives,
it affects the combs, and the bees getting a distaste for their home, will work
slowly, and often desert it altogether. The culture of bees has, for some years
past, been an object of much attention in this country, and numerous improve-
ments have taken place in the construction of the hives, by which the cruel
practice of destroying the bees to obtain their honey is obviated, and the pro-
duce is very considerably increased by the management of the hives and their
inmates. Amongst those who have turned their attention to this subject, Mr.
Mott, of Moulton Chapel, Lincolnshire, stands distinguished for the improve-
ments he has introduced in the structure of beehives, and the management of
the bees. . The most essential part of his plan consists in regulating the heat of
the hives by means of ventilation, so as to prevent the swarming of the bees;
at the same time obliging them to exchange a hive filled with honey for an
empty one placed by the side of it. The cut represents an elevation of one of
the forms of hives adopted by Mr. Mott, inclosed in a frame like that of a
watchman's box, but surrounded by trellis-work (not shown) instead of close
boards. The lower portion q l being the warmest, is the apartment for the
queen and the larvae. The entrance for the bees is at a narrow hole at the
back of the hive, as at e, near to the ventilators v v, which are tin tubes open
on the outside of the hive, and perforated internally with minute holes (to

BEER MACHINE. 163
prevent the bees from passing through) project-
ing horizontally towards the centre of the
hive; above there is a floor, with large apertures, O
shown by the dots, which are covered by the
receptacles for the honey rr r r, into which a
the bees, therefore, enter from beneath.
The compartment of the hive where these
vessels are placed, is made to open and shut
as a box, the lid of which is shown as - |
º," "" " || |
*... ..., || Tºº
|
i
º
most commonly prepared from malted bar- - - Huanuihuvuui.
ley, although it is sometimes made from J|||}|†,
other kinds of grain, either raw, or malted, :
as wheat, maize, millet; also from sugar |#iº Hi
lift ############ #||
| | | } |
most vegetable substances which contain
saccharine matter, uncombined with any
acid. Beer, or a fermented liquor prepared
from grain, was known to the ancient Egyp-
tians, with whom, indeed, the art of pre-
paring it is supposed to have had its rise.
Beer was also in use with the ancient Gauls,
Saxons, Britons, and other nations of the north
and west of Europe; and is, at the present, a
common beverage in most countries where grain is plentiful, and where the
grape does not flourish. Park and Lander both mention it as extensively used
in various parts of the interior of Africa. It does not appear that either the
Egyptians, or any of the nations of antiquity, used hops, or any similar sub-
stance, with their worts, on which account their beer would not be well adapted
for keeping. This improvement in the art of brewing was introduced in
England about the beginning of the sixteenth century; at the outset the prac-
tice encountered some prejudice; and, in an old act of parliament, hops are
denounced as a poisonous weed. In England, two distinct sorts of beer are
known, called ale, and porter, or beer, and of each sort there are numerous
varieties. Although the difference in the flavour of ale and of porter is suffi-
ciently marked, it is difficult to say in what way it is produced; that it is not
altogether owing to pale malt being used for brewing ale, as some assert, is
clear from the fact that, in many parts of the country, ale is brewed from brown
malt; neither is it owing to a larger quantity of hops being used in making
porter, for the pale ale, which is exported in large quantities from this country
to India, contains a larger proportion of hops than the porter exported to the
same place; neither will a difference in the proportions of the malt to the
water account for it, since some ales are stronger, and others weaker, than
porter. It is also singular that, although capital ale may be brewed in private
families, few persons but the London brewers, who have very large establish-
ments, can make good porter. Although the various causes we have just
noticed may have some effect, we imagine that the difference is principally
caused by the addition of certain ingredients to the worts during the process of
fermentation. This practice, although not openly avowed, is, nevertheless, well
known to be pretty general; and it is also certain that some of these additional
ingredients are of a very noxious and unwholesome description. For the process
of making beer, see BREWING.
BEER MACHINE. An ingenious contrivance, of comparatively recent
introduction, for drawing beer from different casks, situated in an apartment or
cellar beneath, without descending for that purpose; by which means much
trouble and great waste of liquor is avoided. The machine consists of three
or four small lift and force pumps, firmly bedded in two blocks of wood, and
and molasses; and, recently, from mangel
wurzel; in fact, it may be obtained from
|
N-- -
w- * ***-








164 BENZOIN.
inclosed in a handsome mahogany case. To the lower end of each pump is
attached a suction pipe, which is inserted in a cask of beer, (each pump being
employed to draw a particular quality of beer,) and from the upper end of the
pump proceeds a pipe connected to a nozzle in front of the case of the machine.
The piston rod passes through a small stuffing box on the cover of the barrel,
and through a guide, by which its parallel movement is secured; and it is con-
nected by slings to a bent lever, by which it is worked. This lever consists of
a short arm, to which the slings are attached, and stands at an angle of about
1300 with the long arm or handle, which works through a slit in the semicircular
head of the case. A small cistern of white metal is fitted to the case beneath
the nozzles, and from it a pipe conveys the drippings to the waste-butt.
BELL. A hollow vessel of metal, formed to produce a sound by the act of
striking it. The principal uses to which bells are applied, are to sound the
hours, and to summon persons from a distance. The forms of bells vary con-
siderably, some being segments of spheres, others truncated cones, but the most
common form is that in which the sides diminish in a curve line from the base
to the upper edge, the crown being slightly convex. The use of bells is
very ancient and extensive, as they were to be found amongst Jews, Greeks,
Romans, Christians, and Heathens, variously employed. Their first application
to ecclesiastical purposes is said to have been about the year 400, and in the
city of Nola. In Britain, bells were used in churches before the close of the
seventh century. Abroad are bells of dimensions greatly exceeding any to be
met with in this country. At Rouen, in Normandy, was a bell said to weigh
36,000 lbs. At Erfurth is one weighing 28,200 lbs.; its periphery is 143
ells, and its height, 4; ells. In the church of St. Ivan, at Moscow, is a bell
weighing 127,836 lbs. ; but the largest bell in the known world, is the unsus-
pended bell in the Kremlin of that city. It is computed to weigh 443,772 lbs.
In England, the largest is “Great Tom,” of Christ Church, Oxford, weighing
17,000 lbs. ; the great bell of Lincoln weighs 9,894, and that of St. Paul's,
8,400 lbs.
BELL, DIVING. See Diving APPARATus.
BELLOWS. An instrument for directing a current of air against burning
fuel, to increase the combustion. The ordinary bellows, for domestic use, are so
well known, as scarcely to require description, consisting merely of two flat
boards, united by a sort of hinge joint, and having a piece of leather, (broad in
the middle, and narrow at the two ends,) nailed round the sides of the boards,
to allow them to separate or move through a small angle. In the lower board
is a hole, through which the air enters, upon raising the upper board; but being
prevented from escaping on pressing down the upper, by a leather flap valve,
which covers the hole, it is forced through a pipe or nozzle fitted at the junction of
the boards, and having a small valve behind it, opening outwards. For bellows
for manufacturing purposes, see BLowING MACHINEs.
BEN, OIL of. This is obtained from the ben nut by simple pressure. It is
remarkable for its not growing rancid in keeping, or at least not until it has
stood for a number of years; and on this account it is used in extracting the
aromatic principle of such odoriferous flowers as yield little or no essential oil
in distillation.
BENZOIC ACID. An acid commonly obtained from benzoin, although it
exists in various substances, as vegetable balsams, cinnamon, the urine of horses,
cows, &c. . It is usually procured from benzoin, either by sublimation, or by
digesting the powdered benzoin in lime water, and afterwards separating the
lime by the addition of muriatic acid. It crystallizes in fine silky filaments, of
a white and shining appearance, and of a spec. grav. of 0.667; it is soluble
in sulphuric and nitric acids, alcohol, oils, and tallow, but is only slightly soluble
in water. It unites easily with the earthy and alkaline bases.
BENZOIN, or BENJAMIN. A resin which exudes from incisions made
in a certain species of tree growing in the East Indies, particularly Siam, and
the island of Sumatra. This resin is moderately hard and brittle, and yields an
agreeable smell when rubbed or warmed. It is totally soluble in alcohol, from
which, like other resins, it may be precipitated by the addition of water.
BINN ACLE. I65
p.
RERYL, A precious mineral, commonly green, but of various shades, pass-
ing into honey yellow and sky blue. Its spec, grav. is 2.7. It differs from
emerald in hardness and colour. It has been called aqua marine, and greenish
yellow emerald. It is electric by friction, and not by heat.
BEVIL. An instrument for measuring and transferring the angle formed
by two surfaces; it consists merely of two straight legs, turning upon a com-
mon centre, and is used by the two limbs coinciding with the surfaces where an
angle is to be ascertained. The annexed engraving represents an instrument
by which curved surfaces may be gauged, or the curve transferred to any kind
C-5|
|GITC
*s---
E=ºº-º-º:
/
of work, or to paper, a and b Fig. 1, are two rulers connected together by a cir-
cular joint; c is an arch of brass fixed to b, and sliding through a mortise or
slit in a, to which it is fastened at pleasure, at any required angle, by means of
the screw in a pressing upon it. The rule a has six or more square mortises
made through it, (shewn in section in the drawing,) in which are placed as
many nuts moving on pivots; each of these nuts is tapped to receive a long
screw (as at f) working within them ; and each of the long screws is fixed at
one end to a flexible steel blade, e e, by means of a kind of swivel joint which
admits of the screw turning round in it without advancing, and allows it to
press either direct or aslant. Consequently, when the opposite ends of the
screws are turned by the thumb and forefinger, the steel blade is pressed out so
as to adapt itself to any given curve; and being thereby fixed in the same
position, the curved line can be transferred therefrom to any kind of work,
or on to paper. Fig. 2 shews a contrivance for drawing the radii of wheels
with great expedition; it is formed of a slip of thin brass, and the central
hole must be in the line o o ; if now a needle point passing through the
hole be inserted in the centre of the circle representing the wheel, the radii
may be drawn with great facility and exactness along either of the lines o o,
to the different points or degrees previously marked upon the circumference.
BINNACLE. A small case, in which is placed the compass-box. It is fixed
to the deck in front of the steersman, and is furnished with glazed apertures to
admit light upon the compass, and exclude rain in the day, and at night is
lighted up by a lamp placed within it. These lamps are variously constructed;
Y


166 BISCUJT.
sometimes a hole is cut through the deck immediately below the compass,
and a lamp is so placed as to give light to the compass and the cabin also; in
this case the card of the compass is formed of a semi-transparent material.
BINOCULAR TELESCOPE, is a telescope to which both eyes may be
applied at once, and consequently, the same object observed at the same time
with both. It consists of two tubes, with two sets of glasses, of the same
power, and adjusted to the same axis, which has been said to exhibit objects
larger and more distinct than a single or monocular glass. There are also
microscopes of the same construction, but they are very seldom used. -
BIRD-LIME. The best bird-lime is made of the middle bark of the holly,
boiled seven or eight hours in water, and, when soft, it is laid in pits in the
ground, and covered with stones, and left to ferment till it is reduced to a kind
of mucilage. It is afterwards kneaded till it is freed from extraneous matter,
and then washed in a running stream till no impurities appear. In this state it
is left four or five days in earthen vessels to ferment and purify itself, when it
is fit for use. It may likewise be obtained from the misletoe, young shoots of
elder, and other vegetable substances. It is sometimes adulterated with turpen-
tine, oil, vinegar, and other matters. Good bird-lime is of a greenish colour,
and sour flavour; gluey, stringy, and tenacious; and, in smell, resembling lin-
seed oil.
BISCUIT. A species of unleavened bread. There are several sorts of bis-
cuit, each having a distinguishing name; but the most important, from its very
great consumption, is the sea biscuit, destined for the use of shipping. A new
baking establishment having been recently formed at the Royal Clarence Vic-
tualling Establishment, at Weevil, near Portsmouth, upon a scale of magnitude
nearly sufficient to supply the whole royal navy with biscuit, and that of a very
superior description, the following account, taken from the United Service Journal
will, we trust, be acceptable to our readers. “It having been discovered that the
flour supplied to government by contract had, in many instances, been most shame-
fully adulterated, the corn is ground at mills comprised within the establish-
ment, and by which means the introduction of improper ingredients is prevented,
and precisely the proportion of bran which is requisite in the composition of
good sea-biscuit is retained, and no more. The flour-mill is furnished with 10
pair of stones, by which 40 bushels of flour may be ground and dressed, ready for
baking, in an hour. The baking establishment consists of 9 ovens, each 13 feet
long by 11 feet wide, and 17% inches in height. These are each heated by sepa-
rate furnaces, so constructed, that a blast of hot air and fire sweeps through
them, and gives to the interior the requisite dose of heat in an incredibly short
space of time. The first operation in making the biscuits consists in mixing
the flour, or rather meal and water; 13 gallons of water are first introduced
into a trough, and then a sack of the meal, weighing 280 lbs. When the whole
has been poured in by a channel communicating with an upper room, a bell
rings, and the trough is closed. An apparatus, consisting of two sets of what
are called knives, each set ten in number, are then made to revolve amongst
the flour and water by means of machinery. This mixing lasts one minute and
a half, during which time the double set of knives, or stirrers, make twenty-six
revolutions. The next process is to cast the lumps of dough under what are called
the breaking-rollers—huge cylinders of iron weighing 14 cwt. each, and moved
horizontally by the machinery along stout tables. The dough is thus formed into
large rude masses, 6 feet long, by 3 feet broad, and several inches thick. At
this stage of the business the kneading is still very imperfect, and traces of dry
flour may still be detected. These great masses of dough are now drawn out,
and cut into a number of smaller masses about a foot and a half long by a foot
wide, and again thrust under the rollers, which is repeated until the mixture is
so complete that not the slightest trace of any inequality is discoverable in any
part of the mass. It should have been stated that two workmen stand one at
each side of the rollers, and as the dough is flattened out, they fold it up, or
double one part upon another, so that the roller, at its next massage, squeezes
these parts together, and forces them to mix. The dough is next cut into small
portions, and being placed upon large flat boards, is, by the agency of
BIT. 167
machinery, conveyed from the centre to the extremity of the baking-room.
Here it is received by a workinau, who places it under what is called the sheet-
roller, but which, for size, colour, and thickness, more nearly resembles a
blanket. The kneading is thus complete, and the dough only requires to be
cut into biscuits before it is committed to the oven. The cutting is effected by
what is called the cutting-plate, consisting of a net-work of 52 sharp edged
hexagonal frames, each as large as a biscuit. This frame is moved slowly up
and down by machinery, and the workman watching his opportunity, slides
under it the above described blanket of dough, which is about the size of the
leaf of a dining-table; and the cutting-frame, in its descent, indents the sheet,
but does not actually cut it through, but leaves sufficient substance to enable
the workman at the mouth of the oven to jerk the whole mass of biscuits, un-
broken, into the oven. The dough is prevented sticking to the cutting-frame, by
the following ingenious device; between each of the cutter frames is a small
Hat open frame, movable up and down, and loaded with an iron ball, weighing
several ounces. When the great frame comes down upon the dough, and cuts
out 52 biscuits, each of these minor frames yield to the pressure, and are raised
up; but as soon as the great frame rises, the weight of the balls acting upon the
little frames thrusts the whole blanket off, and allows the workman to pull it
nut. One quarter of an hour is sufficient to bake the biscuit, which is after-
wards placed for three days in a drying room, heated to 859, or 900, which
completes the process.” The following statement of the performance of the
machinery is taken from actual experiment: in 116 days, during 68 of which the
work was continued for only 73 hours, and during 48, for only 53 hours each day,
in all 769 working hours, equal to 77 days of 10 hours each, the following quan-
tity of biscuit was baked in the 9 ovens; viz. 12,307 cwt.=1,378,400 lbs. The
wages of the men employed in baking this quantity amounted to 2731. 10s. 94d.;
if it had been made by hand the wages would have been 933l. 5s. 10d ; saving
in the wages of labour, 6591. 7s. 0}d. In this is not included any part of the
interest of the sum laid out upon the machine, or expended in keeping it in
order. But in a very few years, at such an immense rate of saving, the cost of
the engine and other machinery would be repaid. This admirable apparatus
is the invention of T. T. Grant, Esq. Storekeeper of the Royal Clarence Vic-
tualling Establishment, who, we believe, has been rewarded by a grant of 2,000l.
from Government.
BISMUTH. A brittle metal, of a yellowish white colour; it is somewhat
harder than lead, and melts at 4800 Fahr. Urged by a strong heat in a close
vessel, it sublimes entire, and crystallizes very distinctly when gradually cooled.
Bismuth unites with most metallic substances, and renders them, in general,
more fusible. 8 parts of bismuth, 5 of lead, and 3 of tin, form what is called
fusible metal, which melts in boiling water. Bismuth is used in the composition
of pewter, in the fabrication of printers' types, and, combined with lead and tin,
forms plumbers’ solder.
BISTOURY, in Surgery, an instrument for making incisions, of which there
are different kinds, some straight and fixed in a handle like a knife; some are
of the form of a lance, while others are crooked, with the sharp edge on the
inside.
BISTRE. A brown pigment, consisting of the finest part of wood-soot, pul-
verized, and passed through a fine sieve, then mixed with a little gum-water,
made into cakes, and baked. It is a fine transparent colour, and has much the
same effect in water-painting, where alone it is used, as brown pink in oil.
The best is prepared from dry beech wood, by grinding it with water into a
smooth paste, then diluting it with more water. After the grosser liquor has
subsided, the liquor is poured off, and left to settle for a few days; the fine
matter that remains is the bistre. -
BIT. The iron which is put into a horse's mouth, and to which the bridle
is attached. There are various descriptions of bits, but they may all be ranged
under two heads, the snaffle and the curb ; in the snaffle, the bit is formed
slightly curved, and frequently jointed in the middle, and the bridle, or rein, is
attached to rings in the extremities of the bit. Curb bits are generally formed
168 HIT.
with a small semicircular bend in the centre of the mouth-piece, and with arms
or cheek-pieces formed at the ends of the mouth-piece. To the upper part of
the cheek-pieces is hooked a chain passing under the lower jaw of the bone,
and to the lower end of the cheek-pieces is attached the rein, by pulling which,
the upper ends of the cheek-piece are thrown forward, and the curb chain
pressed forcibly against the lower jaw. Curb bits are very powerful in checking
a horse, from the leverage afforded by the cheek-piece, but they tend greatly to
injure the mouth, and cause much uneasiness to the animal. Mr. George
Diggles, of Westminster, took out a patent, some years back, which, for ordinary
riding or driving, is attended with no more injury or irritation to the horse's
mouth than the ordinary snaffle, but which, when occasion requires, instantly
acts as a very powerful curb. This effect is obtained by means of a sliding
piece, with a ring attached to each cheek of the bit, to which ring the rein or
bridle is connected in the usual way; and when it is found necessary to exert a
considerable force in curbing the horse, the pulling of the rein will draw the
slider towards the bottom of the cheek, thus lengthening the lever so consider-
ably that the horse is arrested by an irresistible power. The annexed, Fig. 1,
represents a side view of the improved bit, applied to a horse's head, and in
the ordinary position, when riding or driving; the dotted lines show the position
of the parts when the rein is pulled with considerable force. Fig. 2 gives a
Fig. 1.
front view of the improved oit. a is the riding or driving rein attached to the
ring b, which instead of being fixed to some particular part of the bit, as in the
ordinary bit, is attached to a sliding piece c. A convoluted spring d acts upon
this sliding piece, and keeps it and the ring b up to that part of the cheek
which is near the mouth-piece, Fig. 2, where the leverage being small, the
riding or driving rein will act in the ordinary manner; but when it becomes
necessary to exert an extraordinary power upon the horse's mouth, the rein a
is forcibly pulled back, by which the cheek of the bit is moved out of its per-
pendicular position, and the sliding piece e, with the ring, slides downwards
towards the lower part of the cheek, as shewn by the dotted lines. To prevent
the ring and slider from being drawn too low, a stop is placed on the bit at e
for a riding bit, but for a driving bit, the bar at the bottom of the bit, as seen
at f answers the purpose. When the tension of the rein is relaxed, the elastic
force of the spring draws up the sliding piece c, with the ring b, and the rein a,
to its ordinary place, as represented in Fig 1. The cases i i, which contain
the springs, are made to slide up and down in grooves, formed on opposite sides
of the cheeks, for the convenience of oiling, exchanging, cleaning, or repairing
the springs,

BLASTING. 169
BITTERN. The mother water which remains after the crystallization of
common salt in sea water, or in the water of salt springs. It abouilds with
sulphate and muriate of magnesia, to which its bitterness is owing.
BITUMEN. A term including a considerable range of mineral substances,
which burn with flame in the open air. They vary, in consistency, from a thin
liquid to a solid; but the solids are for the most part liquifiable at a moderate
heat. It also forms a component part of various substances, as jet, amber, and
all the varieties of pit-coal.
BLANKET. A warm, woolly sort of stuff, light and loosely woven, used in
bedding. The manufacture is chiefly confined to Witney, in Oxfordshire, where
it is the principal article of trade. The excellent quality of Witney blankets
has been attributed to the abstersive nitrous water of the river Windrush,
wherewith they are scoured. Blankets are made of felt wool, that is, wool from
sheep skins, which they divide into several sorts. Of the head wool, and bay
wool, they make blankets of twelve, eleven, and ten quarters broad; of the
ordinary and middle sort, blankets of eight and seven quarters broad; of the
best tail wool, blankets of six quarters broad, commonly called cuts, serving for
seamen's hammocks.
BLASTING. An operation resorted to in mines and quarries for the pur-
pose of detaching large masses of earth or stones. The implements employed,
(which are few and simple,) are shown in the engraving. Fig. 1. The sledge

Fig. 1. C- J
2. & 3. [- ~) |
4. 2

5. Cº-
6. (C=
7. C-
8. C- | -
9. ==\_^
hammer, or mallet. Fig. 2. The borer, or chisel. Fig. 3. The wedges. Fig.
4. The scraper. Fig. 5. The claying bar. Fig. 6. The needle. Fig. 7. The
tamping bar. Fig. 8. The shovel. Fig. 9. The fusee inserted in the charge.
To perform the operation of blasting, two men only are requisite. The miner's
judgment directs him to the fittest place for the charge, and a hole is bored or
cut in the rock, in the following manner, to receive it. The borer, or chisel, Fig.2,
is held by one man, whilst the other man strikes it with the hammer or mallet;
the man holding the chisel turning it at every blow, so as to cross the previous cut,
by which means the stone is chipped away by degrees. The boring, or cutting,
is occasionally suspended to clear out the hole, which is done by the scraper,
Fig. 4. When the perforation is of the required depth, (which varies from one
to three feet, the diameter being about an inch and a half) if the hole be wet,
some tough dry clay is introduced, and the claying bar, Fig. 5, is driven in with
great violence, by which means the clay is forced into all the crevices, absorb-
ing the moisture, and preventing the entrance of more; on withdrawing the
claying-bar, the hole is left dry, and of a smooth uniform surface, which adapts
it for receiving the charge. This consists of gunpowder alone, or mixed with

some quicklime, (which it is said increases the force of the explosion); it is
inclosed in paper as a common cartridge, to fit the bore; but in very wet situa-
1 70 BLEACHING.
tions, a tin case is sometimes used to contain it. The charge being now intro-
duced, and thrust to the bottom of the hole by means of a thin tapering copper roë
called the needle, Fig. 6, which is also driven down with the charge. The next
operation is to exclude as much of the air as possible, by reducing the size of
the vent; for this purpose, the tamping bar, Fig. 7, is employed in ramming
round the needle some yielding yet compact substance, so that when the needle
is withdrawn, a very small vent or touch-hole remains. Into this perforation is
dropped a fusee, or rush, charged with powder, on the top of which is fixed a
“snuft,” as it is called, or some other contrivance, so adjusted as to burn a suffi-
cient time to permit the man who fires it to retreat to a proper distance. Pre-
vious to firing, it is usual to give notice to all persons in the immediate
neighbourhood, by blowing a horn or ringing a bell, that they may have the
opportunity of retiring to some place of security.
BLEACHING. The art of freeing cloths and various other substances
from their natural brown or dusky tinge, and rendering them perfectly white.
The most ancient, and at one time the only known, method of bleaching linen,
or cotton cloths, consists in frequently wetting them, and exposing them upon
the grass to the rays of the sun; the powerful action of which in the destruction
of colours is well known. This process, which is distinguished by the term of
“Grass bleaching,” has, however, been nearly superseded by another termed
“Gas, or Chemical bleaching,” founded upon one of those brilliant and useful
discoveries, by which modern chemical science has so honourably distinguished
itself, and rendered such service to the arts of life. Before proceeding to
describe the new, (and now the ordinary process,) we shall give a brief descrip-
tion of the method of grass bleaching, as, although not generally practised, it is
still in use in some parts. The details of the process vary of course with the
nature of the goods; but the following is the process for bleaching flax-yarn,
which constitutes an important branch of business. The first operation, called
steeping, consists in immersing the brown yarn in hot water, or in allowing it
to macerate in cold water, or in alkaline ley. This occasions a kind of fermen-
tation, which loosens the saliva employed in spinning the yarn, and so far
separates the other impurities attached to it, that the whole may be easily
removed by washing in river or spring water. The next operation is that of
bucking, or boiling in an alkaline lye, after which the skeins are exposed on the
grass, for two or three weeks, which latter operation is called crofting. These
alternate operations of bucking, washing, and crofting, are generally repeated
four or five times, each time lessening the strength of the alkaline solution in
which the bucking was performed. The next process is that of scouring, which,
as more anciently practised, consisted in soaking the yarn in milk, which had
become acidulous by age, which was usually employed, for the first time,
immediately after the fourth or fifth bucking. In this liquor, which was tech-
nically called the first sour, the goods generally lay for three weeks, or until
such time as the scum began to crack and subside, when they were usually
taken out and submitted to a repetition of the processes already described. Thus,
whenever the goods had been once soured, the operations of bucking, washing,
scouring, and crofting, were repeated in regular rotation, until the yarn came to a
good colour, and was esteemed perfectly clear. These tedious operations have been
much shortened by substituting very dilute sulphuric acid for the sour milk. This
improvement (suggested by Dr. Home,) so much accelerated the process, that one
souring by sulphuric acid may be performed in from 12 to 24 hours; whilst every
souring by the milk process required from two to six weeks; and the whole process
may by this means be completed in four months, which before required seven or
eight months. We shall now proceed to give a slight history and description of
the new system of bleaching, founded upon the property which chlorine pos-
sesses, of rapidly destroying vegetable colours. By this system, (which fur-
nishes one of the most beautiful illustrations of the immense benefits which
science may render to the useful arts,) the practice of bleaching is con-
ducted with a degree of precision before unknown, and with the most surpri-
sing expedition. For the discovery of chlorine, we are indebted to Scheele,
who, in the year 1774, first formed it by art, and afterwards ascertained its
BLEACHING. 171
powers in destroying vegetable colours. But the first person who made experi-
ments upon this gas, with a view to its application in the arts, was Mr. Ber-
thollet, who, in the Journal de Physique, for June, 1785, and again in the
number for August, 1786, explained the nature of its action on vegetable
colours, and suggested how it might be applied with advantage to the process
of bleaching. The subject soon attracted the attention of various scientific
persons and enterprising manufacturers, and numerous establishments were
formed, in which the process of Berthollet (modified by subsequent discoveries,)
was adopted. Amongst the first to introduce and perfect the new process in
this country, were Professor Copland, the celebrated Watt, and Mr. Henry, of
Manchester. Mr. Watt, so early as 1787, had introduced it in the bleaching
field of Mr. Macgregor, at Glasgow; and in his first attempt, he bleached
500 pieces of cloth; and Mr. Henry, in the year 1788, published an account of
the process, as practised by himself, which account comprehends every thing at
this time known respecting the use of chlorine gas in bleaching, excepting the
condensation of the gas, by means of lime. At the first introduction of the new
process, the chlorine was employed in the state of gas, but this method was
found to be attended with many inconveniences; the fumes occasioning consi-
derable annoyance to the workmen, and the texture of the cloth being frequently
injured by the too great energy of the gas. It was also found extremely diffi-
cult to expose all the surfaces equally to its action, without which no perfect
bleaching can ever be effected. The first remedy for these inconveniences
consisted in condensing the gas in water, and subsequently in a solution of potash,
which imbibed the gas more readily than water alone, and formed a more
concentrated liquor. This latter process was invented by some manufacturers
at Javelle, whence the liquid was named—“Liquer de Javelle.”
In the year 1798, Mr. Tennant, of Glasgow, took out a patent for a new
bleaching liquor, which consisted of a solution of chlorine of lime, instead of
oxymuriate of potash, which, besides being equally efficacious with the former for
general purposes, has the advantage of being much cheaper. It is not, however,
applicable where cottons are subsequently to be dyed with madder: for bleach-
ing these, the oxymuriates of potash or soda must be employed. The peculiar
advantages of combining chlorine with lime, or the alkalies, consists in the cir-
cumstance that the saline solution gives out the gas gradually to the goods which
require bleaching, but does not part with it to the atmosphere with the same
facility. In consequence of this, the operation of bleaching is now not inju-
rious, nor even very disagreeable, to the workmen; whereas, in the former
process, when the gas was merely received into water, it was so freely given out
again that no man could long endure to work in it, or even, for any consider-
able time, to superintend the operations. This advantage of the new process
more than compensates for the diminution of the bleaching power of chlorine,
which results from the aforesaid combinations. Mr. Tennant's patent for the
liquid chloride of lime was afterwards set aside; but he subsequently obtained a
patent for combining chlorine with lime in the dry state. This is a most valuable
improvement, the dry chloride being less liable to decomposition than the liquid,
and being so much more portable, the smaller manufacturers find it more
advantageous to purchase the article of those whose business it is to prepare it,
than to establish works for the preparation of the article themselves. The fol-
lowing is the process as practised in bleaching linen, or cotton cloth, or yarn.
The same methods are followed as far as the fourth or fifth bucking, as
described in the process of grass bleaching, only good washing is substituted
for crofting. The goods are then immersed in a solution of chloride of lime,
or of the chlorides of potash or soda, and are then well washed, by machinery,
in pure water. They are then taken to the souring vessels, containing a portion
of very dilute sulphuric acid, and when taken out of these vessels, are again
well washed in water; and, lastly, they are submitted once more to the alkaline
process already described. Linen goods require, at least, three immersions in
the solution of chloride of lime, followed by an equal number of alternate
immersions in the sours and in the alkaline solutions, carefully and thoroughly
washing them in pure water between each of these processes. čº however,
172 BLEACHING.
require fewer immersions in the bleaching liquor, which may likewise be
more diluted with water for cottons than for linens. By this method of
bleaching, linen goods constantly acquire a yellowish tinge; this, however, is so
superficial, that mere exposure to the air for a few days generally removes it.
The goods are then finished by boiling them for a short time in a diluted solu-
tion of pearlash and white soap, which removes the disagreeable odour which
would otherwise be attached to articles bleached by this process. Cotton goods
do not require crofting, as the yellow tinge, just mentioned, does not appear
in them when finished, being removed by the sulphuric acid, although this acid
will not remove it from linen goods. But the routine just described, Mr.
Parkes (from whose essay on bleaching much of the preceding account is
taken,) observes, is not sufficient for bleaching calicoes intended for the best
madder work. The following outline of a process adopted by a scientific
printer in Scotland, for bleaching calicoes for madder work, or resist work, or
for pale blue dipping, was communicated by him to Mr. Parkes, with an assur-
ance that it may be relied on. The goods, after being singed, º and
squeezed, by passing between rollers, are boiled four times, ten or twelve hours
each time, in a solution of caustic potash of a spec. grav. from 1.01.27 to 2.0156,
washing them carefully and thoroughly between each boiling. They are then
immersed in a solution of the chloride of potash, originally of the strength of
1.00625, and afterwards reduced, with twenty-four times its weight of water;
but as the specific gravity alone is not a perfect guide, the bleaching power of
the liquid is tested by a solution of indigo of a known strength. In the above
preparation, the goods are allowed to remain 12 hours, and are then, by some
printers, laid, whilst wet, on the grass, and exposed to the sun and weather for
two or three days. From thence they are removed to the sours, made of the
spec. grav. of about 1.0254, at the temperature of 1100 Fahr. ; and after
lying five or six hours, are taken to the wheel, and washed. The four boilings
in caustic potash, with the washings between each, are then repeated, and the
goods, after being again immersed in the diluted chloride of potash, are well
washed in pure water, and then rinced in common sours for half an hour. The
last process is that of careful washing in clean water, after which they are
immediately hung up in the airing sheds to dry gradually. Various articles,
besides cloth, such as wax, paper which has become mildewed, &c. are now
bleached by means of chlorine, either in the state of gas, or combined with
alkalies or alkaline earths. The annexed engraving represents the apparatus
employed for the preparation of chloride of potash, or soda, for the use of calico
printers. a is the furnace for heating the materials which furnish the chlorine;
b a cast iron vessel containing water, and forming a water bath for the recep-
tion of the still; c the body of the still made of lead, and the upper part sur-
rounded by a deep cup d'd formed in one piece with it, and containing a portion
of water into which the head of the still descends to the depth of about six
inches, thus forming what is termed a water-joint, which prevents the escape of
the gas; e is the still head descending, as we have just stated, into the water;
in the cup f is a bent funnel, through which the acid is poured into the still ; g
an agitator for stirring the materials in the still, working through an air-tight
aperture ; and h the eduction pipe, by which the gas passes into i, an inter-
mediate vessel, partly filled with water, and designed to arrest any uncombined
muriatic acid which may occasionally rise from the still during the process; k a
safety tube; and l the pipe which conveys the gas into m, the large receiver
made of lead, and charged with the alkaline solution; n the agitator for con-
stantly stirring the alkaline solution; this is necessary to promote the absorption
of the gas; and, in large works, the agitator is moved by power from a steam-
engine; o an opening for filling the receiver, occasionally cleaning it out, &c.;
p discharge cock for drawing off the saturated solution. The junction of all the
various pipes and openings are rendered air-tight by water-joints. At the first
introduction of the new process, the chlorine was obtained by distilling muriatic
acid upon the black oxide of manganese; but it is now procured in a simpler
and more economical manner, by mixing together black oxide of manganese,
common salt, and diluted sulphuric acid; various proportions are used by
BLEACHING. 173
different manufacturers: Mr. Tennant recommends equal weights of salt, oxide,
and acid, aid a quailiity of waier equai to the measure of acid. Silk and
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woollen goods being animal productions, different processes are employed in
bleaching them. The colouring principle of silk being resinous, M. Baumé has
proposed a process for extracting it by digesting the silk in alcohol acidulated by
muriatic acid, but the ordinary method of bleaching silk is the following. The
silk being still raw, is inclosed in a linen bag, and boiled in a solution of soap
for two or three hours, the bag being frequently turned. It is then taken out
and beaten, and next washed in cold water; and, after being slightly wrung, it
is a second time put into the boiler filled with cold water, mixed with soap and
a little indigo, which gives it that bluish cast commonly observed in white silk.
When the silk is taken out of this second water, they wring it hard with a
wooden peg to press out all the soap and water; after which they shake it to
untwist it, and separate the threads. It is then suspended in a kind of stove
constructed for that purpose, in which sulphur is burning, the vapour of which
gives the last degree of whiteness to the silk. Woollen cloths are sometimes
bleached by simply scouring them with soap and water after the operation of the
fulling mills, and sometimes by sulphuric acid gas, which is effected as follows:—
The stuffs are first well washed and cleansed in river water, and then put upon
poles to dry. When half dry, they are exposed to the vapour of burning sul-
phur, or sulphurous acid gas, in a very close stove; the gas gradually adhering to
the surface of the stuff, renders it beautifully white. An improvement upon this
method is to condense the sulphurous acid in water, and immerse the stuffs
therein; by which means the acid acts more equally over the whole surface,
than when in the state of gas. The gas may also be obtained by digesting sul-
phuric acid upon chopped straw, saw-dust, or other carbonaceous matter, in a
retort, and the gas may be condensed by an apparatus similar to that used for
condensing the chlorine gas. High pressure steam has been lately employed
instead of chlorine for bleaching cloths. It is said that this method of bleaching
has long been practised in the east, but Chaptal is the first writer who recom-
mended it to the European bleacher; and Mr. S. Wright has taken out a patent
in this country for an apparatus for washing and bleaching upon this principle,
Z -




174 BLEACHING.
which apparatus is represented in the annexed engraving. The goods to be
bleached are first packed closely into a conical vessel, through which the steam
is caused to pass for a while; the steam is then made to force an alkaline solu-
tion through the goods, to remove the impurities and colouring matter (which
operation is repeated as often as may be necessary); hot water is next im-
pelled through the goods to remove all the alkaline matter; and, lastly, steam
of a high pressure is forced through to expel the water, by which the goods
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are left in nearly a dry state, and perfectly clean, a is a copper vessel, formed as
trustrum of a cone, at the lower part of which is a perforated false bottom, or
grating, and below this the real bottom, from which a pipe descends. The
articles to be operated upon having been previously laid in water and rubbed
with soap, are to be closely packed in this vessel, the lid of which is then
to be screwed down and rendered steam-tight at the junction. In the diagram
this vessel is represented enclosed in a jacket, to prevent the radiation of heat;

BLINDS, 175
B is a vessel (also of copper, as well as the other vessels and tubes repre-
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sented), containing soap aid water, of the usual alkaline solutions of pcarl-āsh,
soda, &c.; C is a pipe leading from a steam boiler, through which is introduced
steam at a pressure of 50 lbs. on the inch, which is first to be gradually admitted
into the apparatus, by partially opening the stop-cock a, when it passes into the
vessel A, where it is allowed to act upon the goods therein deposited, for half
an hour; after which the cock a may be completely opened, and the full force
of the steam allowed to operate, first opening the cocks b, c, d, e, when the
steam will pass up the pipe D into the vessel B containing the alkaline solution.
The pressure of the steam upon the surface of the liquid in this vessel will
now cause it to descend through the pipe E into the vessel A, and herein the
steam continuing to press, will force the alkaline liquid through the goods, satu-
rating every part, and carrying the dirt and other impurities to the bottom, the
liquid passing off through the pipe F into the receiver G underneath. The
lº of steam is next employed to refill vessel B with the discharged alkaline
iquor; for this purpose the cocks b, c, d, e, are to be closed, and the cocks f
and g, to be opened; the steam will now pass down the pipe H, and operate
with its full force upon G, thereby forcing the liquid up the pipe II again into
B, from whence it is again forced through the goods in the vessel A, repeating
the operation as often as may be necessary, in order perfectly to cleanse them.
The dirt, and other impurities, being removed, the next process is that of rinsing,
which is effected by closing the cocks b, c, d, e,f, g, and opening those at h, ś, k,
when the steam from C passes up the pipe K into the vessel L, which is filled
with clean hot water; the full pressure of the steam being now transferred to the
surface of the hot water, forces it through the pipe M and through the goods in
the conical vessel A, carrying away all the alkaline and other impurities through
the pipe N into the vessel O. The hot liquor in O is now to be returned into
L, by closing the cocks i, k, h, and opening those at l, m, when the steam
passes down the pipe P, and forces the liquor contained in O, up the pipe Q Q,
again into L, for the renewal of the operation; this part of the process being also
repeated as many times as may be deemed desirable, which will depend upon the
condition of the goods. The next stage of the process is drying, which is effected
by closing all the cocks, except those at d, e, and allowing steam, at a
reduced pressure, to pass direct from C into the vessel A again, by which all
the water is driven out from the goods, leaving them nearly all in a dry state,
the steam passing off through the pipe F, and escaping at R. In this part of
the process it is necessary to observe that steam should not be employed at a
greater pressure than 20 lbs. on the inch, and that its action should not be pro-
longed beyond the time necessary to drive off the water. For the bleaching of
piece goods, in lieu of the circular-sided vessel A, the patentee recommends
one with straight sides, diminishing downwards; in this vessel the goods having
been carefully folded are to be closely packed, and, in addition to the steaming
and washing, by means of alkaline solutions, currents of cold air, produced by
a blowing machine, are to be admitted through the pipe S, which, it is said,
eatly assists in whitening the fabric.
BLINDS. Screens composed of various materials, and fixed in window
frames, either to exclude a too strong light, or to screen the interior of an
apartment from the observation of persons on the outside, without obstructing
the view of those within. The contrivances for these purposes are numerous,
and so well known as to require no particular description; we shall, therefore,
only notice a blind for circular headed windows, as these windows are common
in modern churches, chapels, and public building, and the heads have hitherto
been either left entirely without blinds, or the blinds have been awkwardly
contrived, and unsightly in their appearance. Fig. 1 is an elevation of the
arch of a window; a a a metal tube bent so as to fit the head of the window,
and serving as a circular curtain rod; this rod is open all along the upper edge,
as shown in the section Fig. 2; the ends fit into holes at b and c, made through
the window bar at d, at b, a pulley is fixed, corresponding with the holes and
bore of the bent tube a ; an endless band e e e Figs. 1 and 2 enters the tube a
by the end c, goes out at the other end, passes under the pulley b, then crosses
176 BLOCK MACH IN ERY.
the window below the bar d, passes over the pulley c, and then over a spring
catch, or rack pulley, not shown in the drawing. In order to make the blind, a
piece of cloth is taken a little wider than the height of the arch, and rather
longer than its circumference, and is folded like a fan; a nail is then passed at the
bottom through all the folds into the middle of the window bar at d, forming a cen-
.tre to the semicircular tube a a ; holes are made at the other end in the folds, which
allow the blind to slide along the tube; the bottom fold is tacked to the window
bar near the end b; two pieces of tape connect the upper fold with the endless
band by passing through the split tube as shown. The blind is drawn over the
window, or withdrawn from it, according as one side or other of the endless
band is pulled, as in the common roller blind. The inventor of this excellent
contrivance, Mr. H. Goode, of Ryde, Isle of Wight, was presented by the Society
of Arts with the Silver Vulcan Medal.
BLOCK MACHINERY. The machinery at the Royal Dock-yard, at
Portsmouth, invented by Mr. Brunel, for manufacturing blocks, is deservedly
celebrated. The following is a concise account of it. The machines are sepa-
rated into four classes. 1. The sawing machine, for converting the large timber
into proper dimensions for the small machines to operate upon. 2. The machi-
nery to form the shell. 3. The sheave-forming machines. And 4. The pin-
forming machines. The machinery is capable of completing three sets of
blocks of different sizes at the same time, and is worked by two steam-engines
of 30-horse power each. The order of the process is this: the elm trees are
first cut into short lengths proper to form the various sizes of the blocks, by two
large sawing machines, one a reciprocating, and the other a circular saw. These
lengths of trees are next cut into squares, and ripped or split up into proper
sizes by four sawing benches, with circular saws, and one very large reciprocating
saw, which is employed in cutting up the pieces for very large blocks. The
scantlings of the blocks being thus prepared, the next process is that of
Making the Shells. The centre hole for the pin of the sheave is first bored by
a centre bit in the boring machine, whilst a number of others, corresponding to
the number of sheaves which the block is to contain, is bored at right angles to
the former, to admit the first stroke of the chisel, and, at the same time, form

BLOCK MACHINERY. E. fſ
the head of the mortises. The blocks are then removed to the mortising
inachine; here they are firmly fixed to a movable carriage, beneath cutting
chisels, set in a frame moving up and down with extreme rapidity, making,
according to Dr. Gregory, 400 strokes per minute. Each time that the chisel
frame ascends, the moving carriage advances a small space, bringing a fresh
portion of wood under the chisel, until the mortise is cut to the proper length,
when the machine is stopped with the chisel frame at its highest elevation.
The chips cut are thrust out of the mortise by small pieces of steel projecting
from the back of the chisels, which are also armed with two cutters, called
scribes, placed at right angles to the chisels, which mark out the breadth of the
chip to be cut at each stroke, and at the same time leave the sides of the mor-
tise so true as to require no further trimming. The corners of the block are
next taken off at a circular saw table, and it is then removed to the shaping
machine; here the blocks are fixed in grooves in the peripheries of two equal
wheels fixed upon the same axis, the distance between them admitting of regu-
lation to suit various sizes of blocks, each wheel having ten grooves, so that ten
blocks are shaping at once. These wheels are made to revolve with great velo-
city against a cutter set in a slide rest, which, moving in a curved direction to
the line of the axis, cuts those outward faces of the block to their required
figure. As soon as the tool has traversed the whole length of the block, the
machine is thrown out of gear, and the blocks are (without removing them)
each turned one-fourth part round, and another fourth-part of their surface is
exposed to the cutter. When the remaining portions of the surface are shaped,
the ten blocks are removed, and the last operation is performed by the scoring
machine, which, by means of a cutter, scoops out a groove round the longest
diameter of the block deepest at the ends, and vanishing at the central hole for
the pin. There only remains to remove any little roughnesses, and give the
surface a kind of polish, which is done by hand, and the shell is then complete.
Of the Sheaves. These are mostly made of lignum vitae, which is cut into
slabs of a proper thickness by circular saws, and then removed to a crown saw,
which bores the centre hole, and at the same time reduces the circumference to
a circular figure. The sheave is then placed in the coaking machine, which
forms a recess on each side of the block to receive the bush or coak, which is a
triangular form, with the ends rounded off. The machinery for effecting this is
extremely ingenious, and acts with such accuracy, and the coaks are cast so true,
that a single tap with a hammer is sufficient to fix the coak in its place. Three
holes are then drilled through the two coaks and the intervening wood, and pins
being inserted in the holes, they are placed under the riveting hammer, which
strikes the pins with a velocity proportioned to the pressure which the workman
exerts upon the treadle. The centres of the coaks are next broached by a steel
drill, and the sheave being removed to a lathe, which cuts the groove on the
periphery whilst it faces the sides, the sheave is completed. There remains now
only the iron pin, which, passing through the two sides of the shell, serves as the
axis on which the sheave turns. These pins are also made, turned, and polished,
by a machine for the purpose; so that, with the exception of strapping by rope
or iron, the block is now complete. The whole cost of the machinery, steam-
engine, buildings, interest of money, &c. was 53,000l., and which, by the saving
effected by the machine, was completely cleared in four years: Mr. Brunel
received on the whole about 20,000l. It is calculated that the machine made
140,000 blocks of various descriptions per annum, from the year 1808 to the
conclusion of the war, which was found to be not only sufficient for the service
of the navy, but also of the ordnance department.
Although the foregoing account of the operations of the several machines will
convey to the intelligent reader a sufficiently clear idea of the whole process by
which the blocks are made, we doubt not that a representation of some of the
principal machines will be acceptable to our readers. To give engravings of
the whole of them would cause us to extend this article to too great a length;
as, independently of the various saws by which the trees are cut up into blocks
and slabs of the proper dimensions, (which saws may be considered as applicable
to other purposes), there are a great variety of machines employed in the
178 BLOCK MACHINERY.
subsequent operations. These may be said to constitute the block-making machi-
nery, properly so called; and from these we have selected two of the principal, to
form the subject of the accompanying engravings. Fig. 1 is a side elevation of the
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mortising machine, in which the mortises for the sheaves are cut. a a the bed
of the machine; b a sliding carriage; c the block to be mortised, securely held
in the sliding carriage by the screw e ; f one of the cutters, the number of
which depend on the number of sheaves the block is to contain; g the cutter
frame, moving vertically in guides fastened to the two front pillars of the
machine, one of which pillars is removed in the figure, in order to show the
cutter frame; h, a guide rod attached to the upper part of the cutter frame, and
moving in a collar j; k connecting rod, attached at the upper end to the cutter
frame, and at the crank l fixed upon the shaft in, which is driven by a strap
from the steam-engine passing round the drum m, which is bolted to the fly-
wheel o. The fly-wheel is loose upon the shaft, which is attached to, or detached
from, the fly-wheel, by a friction-clutch p, which enters the comical interior of
the drum n, and which is moved by the levers q q.; r is a double-threaded
screw, by which the sliding carriage is advanced; it works in a nut s, which
turns in a bearing t , to this nut are attached the rachet-wheel v and the cog-
wheel w; w a pinion acting upon w, and turned by the handle y, and only used
to bring the blocks under the cutters for the first cut, after which the carriage is
advanced by the machine in the following manner:—Upon the shaft m is an
eccentric 1, which acts upon a roller 2 in a vertical lever 3, to the lower end of
which is jointed a horizontal bar 4, which has a tooth acting upon the teeth
of the ratchet-wheel, so that at each revolution of the axis the eccentric
|












BLOCK MACHINERY. 179
thrusting out the upper end of the lever 3, moves in an opposite direction the
retchet-wheel v, which, by means of the nut s, turns the screw, and advances
the sliding carriage, so as to bring a fresh portion of the block under the
cutters. When the whole length of the mortise is cut, the advance of the
carriage further is prevented as follows:—The extremity of the bar 4 is pro-
longed beyond the ratchet-wheel, and rests upon the lever 5, which turns upon
a pin in one of the upright columns of the frame. The lever 5 is supported by
the curved end of the lever 6, the other end of which rests upon an adjustable
slide 7, which is screwed to the sliding carriage, and which is so fixed, that when
the mortise is completed, the long arm of the lever 6 is no longer supported by
the slide; the long arm of the lever consequently descends, and, by its descent,
raises the lever 5, which lifts the bar 4 clear of the teeth of the ratchet-wheel.
Fig. 2 is a side elevation of the shaping machine; a is a large circular rim, or
Fig. 2.
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chuck, firmly keyed upon the shaft; b a similar chuck; c (which cannot be
shown in the drawing) is placed upon the shaft behind a. This chuck is not
made fast, but may be set upon the shaft at any required distance from a to suit
the different sizes of the blocks; d d are stay bolts passing through the chucks
a and c, and having nuts at the back of c to retain it at the requisite distance
from a ; ee are the blocks which are to be shaped; they are retained between the two
chucks a and c, as follows: ff are a number of short maundrils, set in the chuck
a, and each carrying on the farther end a small cross, the extremities of which
have two sharp steel rings; in the chuck c is a screw, opposite to, and concentric
with, the maundrils ff; the inner end of these screws having a sharp steel ring
loosely fitted upon them. Each block, in the operation of boring the holes pre-
vious to passing to the mortising machine, has had the line of its axis deter-
mined, by the marks of two steel rings impressed on one end, and of a single
ring upon the other. The marks of the two rings are applied to the steel ring
on the cross, and the ring on the screw is advanced by the screw to the single
mark on the other end of the block; g is a slide rest, supported upon the bed
h, and attached to the radial bar j, which turns upon a centre directly beneath
the line of the axis of the shaft b ; / is the bar carrying the cutter l, and sliding
















































186 BLOCKS,
in a mortise; m a steel spindle, passing through a socket in k, and having a
small horizontal roller n fitted upon its lower end; o one of two pillars sup-
porting two curved bars p q, called shapes; the curve on one bar determining
the shape of the faces of the blocks, and that of the other bar the shapes of the
sides of the blocks, r is a lever by which the cutter bar is moved along its
mortise, so as to cause the roller n to press against one of the shapes p or q 5 s
is a bar attached to the slide rest, by which the rest is made to traverse the bed
h, describing a portion of a circle of which the pivot of the radial bar is the
centre. The operation of the machine is as follows: the chucks being filled
with a number of blocks corresponding to the number of maundrils, the chucks
are set in motion by a strap from the engine passing round the drum t keyed
upon the shaft b. The cutter l being previously adjusted to the proper distance,
the attendant holding the bars in his right hand, causes the slide rest slowly to
traverse the bed h, whilst, by the lever r, held in his left hand, he keeps the
roller n in contact with the shape p or q, and consequently causes the cutter l to
describe a curve similar to that of the shape; and that face of the blocks which
is exposed to the cutter revolving with extreme rapidity against the cutter, is
cut to a corresponding shape. When the first side is completed, the blocks and
the chucks are stopped, and the blocks are turned one-fourth round, so as to
present the next side to the cutter. This is effected by the following means: on
the outer end of each maundril is fixed a worm wheel v, upon which an endless
screw upon the outer end of the spindle w acts; upon the other end of each
spindle is fixed a bevilled pinion y, gearing with a bevilled wheel w, fitted loose
upon the axis. When it is required to turn the block, the wheel a is locked to
the frame by a catch pull (not shown) and the attendant turns round the chucks
a and c four times, and the bevilled pinions revolving round the wheel a cause
the spindles on which the endless screw is cut to turn the worm wheels one-
quarter round. The roller n is then by a simple movement pushed down, so as
to act against the lower shape; the chucks are again set in motion, and the slide
rest being made to traverse back over the bed, the second face is shaped, and
the operation is repeated for the other two sides.
BLOCKS, in the Navy, and Marine Architecture, a species of pulley very
extensively used for moving heavyweights, by means of ropes or chains passing
over the pulleys; also occasionally in architectural and other works. A block
consists of one or more pulleys, called sheaves, which are generally formed of
lignum vitae, or some hard wood inserted between cheek-pieces forming what is
called the shell of the block, and turning upon a pin passing through the shell
and the centres of the sheaves. Blocks are of various forms, each having a par-
ticular name; the following cut represents a common single block; a is the shell,
b the sheave, c the pin. Blocks are suspended by straps, either of rope or iron;
the latter are called iron-strapped blocks, and have frequently a swivel-hook. A
combination of two blocks, one of which is attached to the load to be raised, is
called a tackle, and the power is to be estimated by the space through which
the fall (which is that part of the rope to which the power is applied) passes,
compared with the space through which the load is raised, deducting for
friction, which is great, owing to the rigidity of the ropes, and the small
diameter of the sheaves; these, for nautical purposes, are necessarily limited by
considerations as to weight and space. The friction is also considerably in-
creased, in certain circumstances, under which blocks are applied. When there
is more than one sheave in the same block, the fall comes last over the outside
sheave; and that sheave, if the exertion of power be in a line nearly parallel
to the direction in which the load is drawn, always endeavours to get into a line
with the point of suspension; for the great friction to be overcome preventing
the equal transmission of the power throughout the combination, and the outside
sheave having to sustain not only the pressure of its own share of the load,
but also the additional strain sufficient to overcome the friction of the other
sheaves, and the vis inertiae of the entire load; it must, therefore be consi-
derably depressed, and in consequence of this oblique direction of the block,
the lateral friction of the sheaves becomes so great, as in some cases nearly to
equal the power. Figs. 1 and 2 represent blocks so constructed as to allow
BLOCKS.
181
the fall to pass over the middle
sheave, by which means it will be
immediately beneath the point of
suspension. Fig. 1 is the invention
of the celebrated Smeaton, who
employed blocks of this description
in erecting the Eddystone Light-
house. The upper block a contains
6 sheaves ranged in two tiers, and
the lower block b contains also 6
sheaves, also ranged in two tiers;
the lower tier of sheaves in a, and
the upper tier of sheaves in b, being
more than two diameters of the rope
smaller than the other sheaves, the
mode of reeving the rope is as fol-
lows. Beginning in the middle, the
rope is reeved over the large sheaves
as far as it will go; thence going
to the first of the smaller sheaves,
they are reeved throughout; thence
again to the outer one of the re-
maining large sheaves, and ending
upon the middle sheave of the upper
block. The principal objection to
this method is, that it requires a
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combination of at least twelve sheaves, and is not therefore applicable to general
purposes. The construction shewn in Fig. 2, which is the invention of Mr. Jones,
of High Holborn, can be applied to any number of sheaves from 4 upwards.
The cut represents a pair of blocks of 2 sheaves each.
To the upper block
a is attached another block b, the sheave of which stands at right angles to the
former, and is called the cross-sheave; the lower
block c contains two sheaves abreast, (shewn di-
verging,) in order that the cross sheave may not be
of a very small diameter. The method of reev–
ing is to begin upon the middle upper sheave,
and when arrived at the outer sheave, to pass to
the cross sheave, which carries the rope over to the
outer sheave, on the opposite side, and then proceed
again in the order of the sheaves.
The annexed figure represents an improved cat-
block, invented by Mr. Bothway, and rewarded by
the Society of Arts. The advantages which this
block possesses over those in common use, are
thus stated by Mr. Bothway. “In all large class
ships in the royal navy, the unwieldy nature of the
usual cat-block requires that two men should be
sent out on the anchor, a most perilous service in
rough weather; whereas mine only requires one
man at any time, because he has not to sustain the
whole weight of the block, as in the former case,
but only that of the hook. And in vessels smaller
than line of battle ships, in blowing weather, when
the ship pitches heavily, the anchor may be hooked
without a man going on it, by his standing on the
head, and guiding the hook of the block to the
anchor, by a staff and hook, similar to a boat-hook.
This facility is gained by the mobility of the
swivel in its socket, so that the man has not the
weight of the block to turn, in order to insert the
A A


182 BLOCKS.
hook in the ring of the anchor. Should the anchor, when hooked in the dark,
or otherwise, cause a turn in the fall, the hook being on a swivel joint, the turn
will come out before the strain comes on the block; and when the anchor is
foul it can also be hooked with great facility. In my thirty-two years' service
I have seen the wooden cat-blocks swell so much in cold climates, that the
sheaves have become immovable; mine, being of metal, are liable to no such
inconvenience.” Another great advantage may be derivable from Bothway's
cat-block being applicable to other uses; whereas the old ones are not. For
instance, by merely having a spare socket or two fitted with hooks of various
sizes, it may take a strap for gear-blocks, or it may be converted into a lashing-
block without the hook and socket, but with the socket bolt. In the figure,
which represents a perspective view of the block, it will be seen that the hook,
instead of being formed in one with the strap, turns with a swivel head, in a
socket which hangs from a pin passing through the lower end of the shell.
Although entirely formed of metal, they are lighter than wooden ones with
their iron bindings, and capable of the same service.
There is another species of blocks, which are termed “Dead eyes,” and are
used for tightening or setting up, as it is called, the standing rigging of ships. It
consists merely of a circular block of wood, with a groove on its circumference,
Wº%
round which the lower end of the shroud, or an iron strap, is fastened; three
holes passing through the face, (ranged in a triangle,) to receive the laniard
or smaller rope, which forms a species of tackle for tightening the shrouds.
There are no sheaves in the dead eye, but the edges of the
holes are rounded off to prevent cutting the laniard, but this
very imperfectly answers the purpose; as from the roughness
of the grain of the wood, which is usually elm, and from the
stiffness of the rope, the laniard renders with difficulty, and
from the great strain to which it is subjected, it is frequently
broken. A very simple and effectual improvement has been
made in this respect by Mr. Carey, Surveyor of Shipping,
at Bristol, by inserting a half sheave of lignum vitae into each
of the holes, which causes the laniard to render with greater
facility, and the shroud to be set up in half the usual time.
Fig. 1 shews the dead eye; Fig. 2 a section of the same;
and Fig. 3 one of the half-sheaves. It will be seen from the
manner of inserting the half sheaves, as shown in Fig. 2, that
they cannot fall out, for the more pressure there is on them,
the faster they will be.
The annexed figure represents a block of a peculiar
description, intended for forming a kind of rope-road to a
stranded ship. When a vessel thus circumstanced has had
a rope thrown over by Capt. Manby's apparatus, or any other
means, considerable difficulty has been found in reeving an
ordinary pulley for the conveyance of the crew to the shore.
In the figure, it will be seen that the pulley divides at the
hook, or shackle, into two equal parts, so that it may be


BLOWING MACHINES. 183
instantaneously passed on to a stretched rope, and, by means of a cord from
the ship, persons luay pass securely and quickly backwards and forwards.
The little bar which traverses the opening is fixed at one end by a joint,
and fits into a mortise, as shown; the use of it being to confine the rope
in its place, when any vehicle, or other apparatus, is slung or suspended
to it.
BLOOD. The principal use of blood in the arts is for making Prussian blue,
or sometimes for clarifying certain liquors. It is also recommended in agriculture,
as an excellent manure for fruit trees. A mixture of blood with lime makes an
exceedingly strong cement; and hence its use in the preparation of some che-
mical lutes, the making floors, &c.
BLOOM. A mass of iron after having undergone the first hammering,
called bloomary. It requires many subsequent hammerings or rollings to render
it fit for smiths' use. See IRoN.
BLOTTING PAPER. A species of paper made without size, serving to
imbibe the wet ink in books of account, &c. See PAPER MAKING.
BLOWING MACHINES. Machines employed for producing a rapid com-
bustion of fuel, by furnishing a more copious supply of air than can be obtained
by the mere draft of the ordinary chimneys. Although the common bellows is
undoubtedly a blowing machine, yet the term is generally restricted in its appli-
cation to those machines which are employed at large furnaces, as in foundries,
forges, &c. Blowing machines are constructed of various forms, the great
object in all being, that the blast should be as continuous and uniform as possible.
The method of producing such blast by a centrifugal force has long been known,
but the first blowing machine on this principle, of which we have a distinct
account, is that invented by Mr. Teral, in 1729. It consists of a number of
vanes or fanners, radiating from a horizontal shaft, and enclosed within a cylin-
drical box, having two apertures at opposite sides of the cylinder, to one of
which is fitted a conical pipe leading to the furnace, whilst the air enters by the
other aperture, and the shaft being turned with great rapidity, a copious and
uniform current of air may be impelled through the conical pipe to the furnace.
From the great simplicity and cheapness of these machines they have recently
been coming into more general notice.
Another kind of blowing machine, and which is very extensively used for
smiths' forges, is the double bellows. This machine in form resembles an ordi-
nary single bellows, but is divided into two parts by a middle board, similar to
the bottom board, and like it furnished with a valve opening upwards. The
upper and under boards are each loaded with weights, which compress the upper
and distend the lower compartments, and the middle board is supported in a
horizontal position upon a frame. The pipe or nozzle of the bellows commu-
nicates with the upper compartment of the bellows only whilst the air is admitted
by the valve in the lower compartment. . The action of the machine is as
follows: The lower board being raised by the brake or handle, the air contained
in the lower compartment is driven through the valve in the middle board into
the upper compartment, and not escaping from it through the nozzle, as fast as
it is forced into it, it elevates the upper board, and thus distends the upper com-
partment. Upon the descent of the lower board, the valve in the middle board
closes, and the upper board descending by the pressure of the weights upon it,
the air beneath it is urged through the nozzle in a continuous current. During
the descent of the lower board, the air enters by the valve in the board, and fills
the lower chamber of the bellows; and upon the rise of the board it is forced
into the upper chamber as before, and thus a continuous blast is maintained.
But although continuous, it is not quite equal, or of a uniform force; for during
the up-stroke the air is compressed by a force exceeding that of the weights on
the upper board, since it causes the upper board to ascend; but upon the descent
of the lower board, the air is expelled by the pressure of the weights alone,
which, being at all times the same, the current is then nearly uniform.
Another species of blowing machine is the water bellows, invented by
Hornblower, several of which machines have been erected in various parts of
the country. The nature of these machines will be readily understood by the
184 BLOWING MACHINES.
help of the following diagram
The side figure is a vertical
section of the machine. a is
the fulcrum of the lever or
beam, with two inverted vessels
b and c suspended from its ex-
tremities; these vessels are
open underneath, but air-tight
above. d and e are two larger ||
vessels, filled with water to the
same level in which the vessels
b and c rise and fall alternately.
g h a 1s a tube or pipe, which
passes through the vessels d and
e, and reaches above the surface
of the water; at the extremities are two valves, (omitted by mistake) which
respectively open outwards into the inverted vessels, with a pipe at h open to
the atmosphere. k and l are pipes passing through the bottom of d and e, and
extending a little above the surface of the water; they are open at top, and have
valves at bottom opening into the trunk o, to which the pipe is fitted which con-
ducts the blast to the furnace. An alternating motion being imparted to the
beam by a steam engine or other first mover, the air passes up the tubes g h i
and fills each inverted vessel as they are successively drawn up out of the water;
the descent of the inverted vessel closes the valves at g and i, and opens those
at the bottom of the tubes k and l, through which the air is driven forward by
the trunk o, and thus, by the reciprocation of the beam, a continual blast is
maintained through the trunk o and the tuyere of the furnace. . -
But the most perfect blowing machines are those in which the blast is pro-
duced by the motion of pistons in a cylinder. The annexed engraving represents
a blowing machine of this description, erected by Mr. Paterson, of Lanark. It
consists of two double acting force pumps, placed at right angles to each other,
to equalize the draft; they are driven by a water-wheel of 5-horse power, a is
# =
the vertical cylinder, 5 the horizontal cylinder; c c two connecting rods united
to the crank d, e the working beam ; f the parallel motion; g the pipe for con-
veying the blast to the cupola or furnace h; ; a small wheel, running in a groove
in a cast iron plate; j frame supporting the vertical cylinder, between which the
lowermost connecting rod c passes. . At k k are placed valves, to admit the air
into the vertical cylinder; similar valves are placed at the ends of the horizontal
cylinder into it. The operation is simply this: by the revolution of the crank
the air is drawn in at each end alternately of both cylinders, and at the same
time it is forced out at the opposite extremity along the pipeg into the furnace;
and the cylinders being placed at right angles, one piston will be moving with
its greatest velocity whilst the other is moving with its least velocity, by which
means the blast is rendered nearly uniform, and an air chamber or reservoir
rendered unnecessary. The first cylinders of magnitude used as blowing
machines, were erected by Mr. Smeaton, in 1760, at the Carron Iron Works,
the cylinders being four in number, 4 feet 6 inches in diameter, and the piston
making a stroke of 4 feet 6 inches in length; but the blowing machine *.



BLOW FIPES. 185
erected at the Smithery, in the Royal Dockyard at Woolwich, is perhaps the
most powerful and the most complete in the kingdom.
In this machine there are three blowing cylinders, of 4 feet 8 inches diameter,
with a stroke of 4 feet 8 inches, and each cylinder making 20 strokes per
minute, expelling near 5000 feet of air per minute. Over the wind chest is
fixed a regulating cylinder, which has no bottom, being open to the wind chest;
and its piston, which weighs 700 lbs. serves only to regulate the pressure, which
amounts to about 4 lb. per square inch. When the pressure exceeds this, the
piston rises, and opens an escape valve at the back of the cylinder.
BLOW PIPE. An instrument for exciting intense combustion upon a small
scale; it is extensively used in many branches of the arts, and also in philoso-
phical experiments upon metallic substances. In its simplest form it is merely
a conical brass tube, curved at the small end, in which is a very minute aperture;
and a stream of air being urged through it by the mouth against the flame of a
lamp or candle, a heat equal to that of the most violent furnaces may be pro-
duced. The body intended to be operated upon should not exceed the size of a
peppercorn, and should be supported upon a piece of well-burned close-grained
charcoal, unless it be of such nature as to sink into the pores of the charcoal,
or to have its properties affected by its inflammable quality. Such bodies may
be placed-in a small spoon made of pure gold, silver, or platinum. Many
advantages may be derived from the use of this simple and valuable instrument.
It is portable; the most expensive materials, and the minutest specimens of
bodies, may be used in the experiments; and the whole process is under the eye
of the observer. In the blow pipes used by enamellers, glass-blowers, and
others, the current of air is maintained by a small pair of double bellows.
Early in the present century, Dr. Hare, of Philadelphia, made a most im-
portant improvement in the blow pipe, by substituting for the flame of a lamp
that arising from a mingled current of oxygen and hydrogen, by which means
he succeeded in producing a more intense heat than had ever been obtained
before, except by the concentration of the sun's rays in very large and powerful
lenses. As these gases, however, can only be procured by chemical means, a
more perfect method of supplying the currents of gas than by means of the
common bellows became desirable, on account of the great leakage of the
latter, and the Doctor, turning his mind to the subject, devised a machine
equally applicable for supplying either oxygen gas or common air. This machine,
which he denominated the Hydrostatic Blow Pipe, is represented in the annexed
engraving, of which the following is an explanation.
The Hydrostatic Blow Pipe consists of a cask, divided by a horizontal diaphragm
into two parts D D. From the upper apartment, a pipe of about 3 inches dia-
meter (its axis coincident with that of the cask) descends, until within about
6 inches of the bottom. On this is fastened by screws, a hollow cylinder of
wood B B, externally 12 inches in diameter, and internally 8 inches. Around
the rim of this cylinder a piece of leather is nailed, so as to be air-tight. On
one side a small groove is made in the upper surface of the block, so that a
lateral passage may be left when nailed on each side of the groove. This lateral
passage communicates with a hole bored vertically into the wood by a centre
bit; and a small strip of leather being extended so as to cover this hole, is
made, with the addition of some disks of metal, to constitute a valve opening
upwards. In the bottom of the cask, there is another valve opening
upwards. A piston rod, passing perpendicularly through the pipe from the
handle h, is fastened near its lower extremity to a hemispherical mass of lead
L. The portion of the rod beyond this proceeds through the centre of the
leather which covers the cavity of the wooden cylinder, also through another
mass of lead like the first, which, being forced up by a screw and nut, subjects
the leather between it and the upper leaden hemisphere to a pressure sufficient
to render the juncture air-tight. From the partition, an eduction pipe E is carried
under the table, where it is fastened by means of a screw to a cock which
carries a blow-pipe, so attached by a small swivel joint, as to be adjusted in any
required direction. A suction pipe passes from the opening covered by the
lower valve, under the bottom of the cask, and rises vertically close to it on the
186 BLOW PIPES.
outside, terminating in a union joint for the attºn” of any º: tube
which may be necessary. The apparatus being thus arranged, †: . e º:
supplied with water until the partitiºn is covered to about the depth of 3 inches,
if the piston be lifted, the leather will be bulged up, and will remove in 1.
degree the atmospheric pressure from the cavity beneath it, consequently § €
air must enter through the lower cavity to restore the equilibrium. When the
| fºn, Q
piston is depressed, the leather being bulged in an opposite direction, the cavity
beneath it is diminished, and the air being thus compressed, forces its way
through the lateral valve into the lower compartment of the cask, which com-
partment being previously full of water, a portion of the fluid is pressed up
through the pipe into the upper apartment. The same result ensues each time
that the stroke is repeated, so that the lower compartment soon becomes filled
with air, which is retained by the cock until its discharge by the blow pipe is
necessary. Dr. Hare, in his oxy-hydrogen blow pipe did not mix the gases in
his gas reservoir, but supported the flame of the hydrogen by a current of
oxygen issuing from different jets. Subsequently, it was found that the heat pro-
duced was materially affected by the proportions in which the gases were mixed,
and that the greatest intensity of heat was obtained by two volumes of hydrogen
united with one of oxygen; and various attempts were made to mix and burn
the gases in their due proportion, but with little success, until the important im-
provement effected in the instrument by Dr. Clarke, Professor at Cambridge.
This improvement consisted in first mixing the gases in a bladder, in the exact
proportions to form water, and afterwards condensing them in a strong iron
chest, by means of a condensing syringe. To an opening at the end of this chest
he attached a great number of layers of fine wire gauze, through which the
mixed gases were driven by their elastic force into a small tube, at the end of
which they were inflamed. By this arrangement he obtained a much greater
heat than had been effected by Dr. Hare's invention, and was enabled to make
a great number of experiments highly interesting to science. Unfortunately,
however, for the general adoption of his plan, it was soon found that his in-
strument was unsafe to use; that the wire gauze would not prevent the explosion
of the gases; that in several cases, when used by the most experienced and
cautious operators, the instruments were burst. The explosions were tre-
mendous, and resembled the bursting of a bomb, the fragments of the iron



BLOW PIPES. * - 187
chest being scattered with great force in all directions. After trying various
plans to render the invention safe, the Doctor, as a protection, had the iroi chest
placed behind a brick wall at the back of the operator, the gases being conveyed
through a tube passing through the wall. In this state the instrument remained,
until Mr. Goldsworthy Gurney applied himself to its improvement, and after
numerous experiments, which are highly interesting, and are fully detailed in
his published lectures, he succeeded in producing an instrument unattended with
the slightest danger in its use, and admirably adapted both for scientific inves-
tigation, and for various operations in the arts. The annexed engraving is a
| |
§
representation of the instrument. A is the safety chamber; B a water trough,
through which the gas is made to pass from the gasometer D by the cock C,
through a tube which reaches to the bottom of the water trough; E is a cock
fitted into the neck of the same, from which it is thrown out should an explosion
take place on the surface of the water. F is a gauge, to indicate the necessary
height of the column of water in the trough. G is a transferring bladder, which
is made to screw and unscrew to and from the stop-cock H, for the purpose of
supplying the gasometer with gases, which may be charged and recharged at
pleasure, by an assistant, during its action, so as to keep up the most intense
flame for any length of time. A valve is placed between the gasometer and the
transferring bladder, which prevents the return of the gas. I I is a light
wooden or stiff pasteboard cap, which combines sufficient strength with great
lightness, so that in case an explosion of the gasometer should happen, it is
merely thrown a short height into the air, by the force breaking the strings
which connect the cap to the press board. To these strings are attached small
wires, which pass through the table of the instrument, as at L, into the press-
board below, where they are secured; this press-board is kept in a horizontal
osition by the stand, so that when the requisite pressure is given to it, the cap
# I is brought to bear equally on the gasometer D. The gasometer bladder (or
silk bag) is tied to a piece of bladder, which screws into a long tube laid into
and across the table, which permits it to be unscrewed at pleasure from the body
of the instrument, and immersed in water when it requires softening, affording
also the means of fixing on another bladder, if any accident should render it
necessary. The stop-cock of the charging bladder G is fixed to one end of the
tube just described, and the stop-cock of the water trough on the other end. To
operate with this instrument, pressure by the hand is applied to the press-board,
which draws down the cap II on the gasometer D, and forces the gas which it
contains through the stop-cock C, and through the water tube and safety chamber
A, to the jet at the end, where it is burned. When the pressure on the press-
board is too slight, or when the hand is taken off, the flame returns into the
safety chamber, and is extinguished. When it is required to suspend the ope-
ration, the hand need only be taken off the pressing board, the water in the
trough acts as a self-acting valve in preventing the escape of gas from the
instrument, and saves the necessity of turning the stop-cock. A silk tube is
attached to the end of the tube before described, in the water trough, which

188 BLUE.
prevents the splashing of the water, sometimes occasioned by unskilful manage-
ment. We omitted to state that the safety chamber A is filled with numerous
discs of very fine wire gauze closely packed, and should the flame be driven in,
which will sometimes happen, it will not enter the bag or reservoir D, but will
explode above the surface of the water in the chamber B, merely driving out
the cork. An improvement has, however, been since introduced in the con-
struction of the safety chamber, by Mr. Wilkinson, of Ludgate-hill, by which
the retrogade motion of the flame appears to be effectually prevented, and a
much larger jet may be employed than heretofore with perfect safety. This im-
provement consists in filling the chamber A with alternate layers of wire gauze
and of asbestos, previously beaten with a mallet, and pulled out to resemble floss
silk. Mr. Wilkinson received from the Society of Arts a silver medal, for his
communication on the subject, and we understand that Mr. Hemming has
recently made some further improvements in the construction of the instrument.
We must here advert to the wonderful effects produced by the oxy-hydrogen blow
pipe, which almost instantaneously reduces the hardest and most refractory sub-
stances. Gun flints are instantly fused by it, and formed into a transparent glass;
china melts into a perfect crystal. All kinds of porcelain are readily fused, pre-
viously assuming a beautiful crystallized appearance. Rock crystal is quickly
melted, giving out a beautiful light. Emerald, sapphire, topaz, and all the
other precious stones, melt before it into transparent glassy substances. Barytes,
strontian, lime, and alumina, exhibit very striking and beautiful phenomena.
Magnesia fuses into hard granular particles, which will scratch glass. The
metals, even platina, are all quickly fused by it; and all descriptions of stones,
slates, and minerals, are melted, sublimed, or volatilized, by its all-subduing power.
BLUBBER, in Physiology and Commerce, the fat which invests the bodies
of all large cetaceous fishes, serving to furnish an oil. The blubber lies imme-
diately under the skin, and over the muscular flesh. In the porpoise it is firm
and full of fibres, and invests the body about an inch thick. In the whale its
thickness is ordinarily 6 inches, but about the under lip it is found two or three
feet thick. The quantity yielded by one of these animals ordinarily amounts to
forty, or fifty, sometimes to eighty or more hundred weight. Its use in trade and
manufactures is to furnish train-oil, which it does by boiling down. Formerly
this was performed ashore in the countries where the whales were caught, but
lately the fishers do not go ashore; they bring the blubber home stowed in
casks, and boil it down there. A machine expressly designed for expressing the
oil from blubber is given under the word OIL.
BLUE (PRussian). A very fine blue pigment, extensively used in the arts.
It is composed of prussiate of iron, and the earth precipitated from alum or
pure alumine. It is commonly obtained by calcining blood or other animal
substances, as hoofs, horns, parings of leather, &c. by which a black coaly resi-
duum is obtained. Three parts of this are added, at intervals, to four parts of
potash, kept in a state of fusion in a stout iron vessel, the mixture being con-
stantly stirred during the process. At first a reddish flame appears upon the
surface of the mass; this afterwards changes to a bluish tinge, denoting the
formation of prussiate of potash, when the whole is to be removed as speedily
as possible into a large vessel of boiling water, and stirred, to promote the dis-
solution of the prussiate of potash. After allowing the dregs to settle, the clear
liquor is drawn off, and fresh quantities of water boiled upon the residuum, until
it ceases to impart much taste to the water; and the whole of the liquor thus
obtained being mixed together, a solution of alum and green vitriol is added, when a
Fº of Prussian blue is immediately formed, which is washed repeatedly to
fee it from the sulphate of potash; after which it is put into bags and pressed,
and then exposed to the air to dry, during which process it assumes a deeper
colour, and acquires a hard stony consistence.
, BLUE (Powder or Stone), used in washing linen, is the same with smalt,
either in the lump or powder. When the smalt is taken from the pot, it is
thrown into a large vessel of cold water; this makes it more tractable, and more
easily powdered. When examined after cooling, it is found to be mixed with a
greyish matter resembling ashes, which must be separated by washing and

BOATS, 189
then the blue substance being powdered and sifted through fine sieves, forms
what is called powder blue.
BLUE (Saxon). The best Saxon blue may be prepared as follows:--mix
1 oz. of the best powdered indigo with 4 oz. of sulphuric acid in a glass bottle
or matrass, and digest it for one hour in a water bath, shaking the mixture at
different times; then add 12 oz. of water to it, stir the whole well, and when
cold, filter it.
BOAT. A small vessel for the conveyance of goods or passengers to short
distances, and which may be impelled either by oars or sails at pleasure. They
are for the most part open or without decks; but the varieties in their form and
construction, according to the purposes for which they are intended, are so
great as to preclude enumeration. Boats always form part of a ship's equipment;
the number depending upon the size of the vessel, and the service for which it
is intended. Of these the cutters, gig, and jolly boat, are principally employed
for the conveyance of officers and crews on any service; and the long boat or
launch, for the conveyance of heavy stores of every description to and from the
vessel. The engraving represents an improvement in this latter class of boats,
when employed for laying out and weighing heavy anchors, and for landing
and embarking cannon. The usual mode of laying out anchors by means of
a ship's launch is, to place the anchor over the boat's stern, and to coil the cable
on the gunwale; but this lumbers up the boat, overloads it, and exposes it to the
danger of being swamped in a high sea. To obviate this, attempts have been
made to sling the anchor beneath the boat, as near as possible in the centre of
gravity of the boat; none of these, however, succeeded so as to encourage their
adoption. Subsequently, Mr. Cow (master boat-builder of the Royal Dock, at
Woolwich,) devised the present arrangement, which was so much approved by
the Navy Board, that they have directed that every ship of war of a certain
class shall be furnished with a launch fitted on Mr. Cow's principle, and the
Society of Arts have rewarded him with a gold medal for the invention. The
former method (alluded to above) for carrying an anchor under a boat's bottom,
was to have only one fixed trunk, which was in the middle of the boat, close to
the side of the keel; the windlass, therefore, could only be supported at the
ends, and was unequal to the heaving up any great weight; the great strain also
was entirely on the sides of the boat. By Mr. Cow's plan there are two movable
trunks at a proper distance from the keel, thereby allowing a strong stanchion
to be placed on the kelson, which stanchion supports the middle of the windlass,
and consequently makes it of sufficient strength to weigh any weight that the
boat is able to sustain. Fig. 1 gives a perspective view of a 74-gun ship'.
launch, with a bower anchor suspended under the bottom, and a bower cable
coiled into the boat, a is the cable; b b the anchor; c c the buoy rope; d a
B B

190 BOATS.
rope by which the anchor is hove up when weighing, or suspended when
carrying, by the windlass. Fig. 2 gives a mid-ship section of the launch, with
two 32-pounders suspended from the windlass. Fig. 2,
h h the guns lashed to wooden slides; iii
ropes by which the guns are hove up to the
boat's bottom ; k k water-tight removable
wood trunks, through which the ropes pass to
the windlass; l l the windlass in two parts . . . . . Tº
connected by a wrought iron gudgeon and §§
socket; m a removable strong wrought iron J is s
stanchion, which supports the middle of the º §§
windlass. The application of the invention sº
to the purpose of landing and embarking
heavy guns is also of great importance, as
it enables this operation to be conducted
on a beach with perfect safety to the men and boats, at times when the surf
is so great as to preclude the possibility of boats approaching near enough to
land or to embark in the usual way; for the boat (with two guns suspended
one on each side of the keel, as shown in Fig. 2) being brought to anchor
without the surf, a small line is the only connexion necessary with the shore,
by which line the larger hauling ropes are conveyed, which being made fast
to the guns, the latter are lowered from the boat, and hauled upon the
beach. Should the operation be carried on where there is a rise and fall of
the tide, and the guns should not be immediately wanted, it will be only neces-
sary to take the boat in at high water, and drop the guns, which may be
taken up as the tide leaves them; in either case the boat is fit for any other
service, without risk of damage by being kept afloat. The interior of the boat
is kept clear for stowing the carriages and other stores. The embarking of
guns is performed in the same way, care being taken to have anchors of suffi-
cient power to moor the boat without the surf, so as to counteract the weight of
the guns, and the resistance it meets with in being hauled off from the shore.
Boats and small vessels are sometimes built flat-bottomed, to allow of their
going into shoal water when required; and in order that they may carry
a sufficient quantity of sail, and to prevent their making lee-way, they are
fitted with what are termed sliding keels. These were first introduced into this
country by Admiral Schank, at whose instance a government vessel, which was
destined for a surveying vessel at New Holland, was fitted with them. These
sliding keels consisted of three stout planks, descending through water-tight
wells to a considerable depth below the ship's bottom, and fitted with apparatus
for raising or lowering them at pleasure. The narrow edge of the plank being
in the line of the vessel's keel, presented but little resistance to the vessel's
sailing, whilst the pressure of the water upon the broad surface of the keels
tended to counterbalance the effect of the wind upon the sails, to depress the
ship, and materially lessened the rolling, and also prevented the vessel going
to leeward, as she must otherwise have done, owing to her extreme light draft
of water. Although a favourable report was made of the invention, it was
never very generally adopted, but it has since been made the subject of a patent,
under a somewhat different form, by Moncrieffe Willoughby, Esq. In his
arrangement a sliding keel of iron, made very massive, is firmly attached to
strong perpendicular iron bars, which are made to slide up and down in water-
tight grooves made through the centre of the hull, thus permitting the keels to be
projected to any required depth in the water, and to be drawn up at pleasure
by means of a simple rack and pinion worked by a winch upon the deck. The
sliding keel is further secured or supported by four chain stays, two on each
side, which pass over the gunwales, and are tightened on board. Fig. 1 is a
side elevation of a vessel fitted with a sliding keel on Mr. Willoughby's con-
struction. Fig.2 a cross section of the vessel, through one of the water-
tight trunks of which the suspending bars pass. Fig. 3 a cross section,
exhibiting the guys or stays attached to the sliding keel. In Fig. 4 the ballast
keel in front of the suspenders is cut off, for the purpose of preventing the

BOATS. 191
** s sº
F \g • le
collection of sea weeds, which would impede the vessel's sailing. The sketch
of a patent ballast-keeled lugger under a press of sail requires no elucidation,
except to remark that the portion below the boundary line of the water repre-
sents the keel under water. Lieut. R. Shuldham's metallic sliding keel resembles
#==
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=
. . . "
sº F. : :
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====Elº


192 BOATS.
the common lee board in its shape, and is shown in the annexed diagram. a
represents the sliding keel lowered down into the water; the dotted line b the
recess into which the keel is raised or deposited when not used; c the joint or
fulcrum upon which it turns on being raised or lowered. One great objection
to the plans of sliding keels is, their interfering with the keel and floor timbers,
which must be cut through, thereby weakening the vessel; for instance, in
Lieut. Shuldham's plan, the keel must be cut through longitudinally, or formed
into two parts throughout nearly the whole length of the vessel, or at least
through a portion as long as the sliding keel; they are also liable to be carried
away, owing to the powerful leverage they afford to the water, and the difficulty
of staying them sufficiently, without forming an obstruction to the speed of the
vessel. The annexed engraving represents a simple plan for preserving the
tholes or rowing pins of a boat, the loss of which is not only teasing, but often
productive of serious inconvenience. Fixed tholes cannot be well used when
HH
boats are to be hoisted in alongside, as they are subject to be broken; they are
also often inconvenient in getting in water casks, as well as in many other
cases. Hence pins which can be unshipped are preferred; these are often lost,
and the want is not always discovered until it cannot be replaced ; or it is not
replaced without a loss of that time which is so valuable at sea. Very often,
also, the delay of a minute is rendered inconvenient or even dangerous when
the boat is dragging alongside by the painter in a heavy sea, and the vessel is
either drifting or standing on. The drawing requires little explanation. By
pulling at the lower pin the two upper ones are fixed at once, and on being
unshipped they hang secure from loss, while the lower one serves as a spare
thole should any be broken. ...”
Before we close this article we must briefly notice Mr. Clint's ballasted masts
for small sailing vessels, the object of which invention is to enable the boat
constantly to retain an upright position, the mast alone yielding to the force of the
wind. Fig. 1 is a section of the vessel, and Fig.2 a plan of the same. a represents
the hull of the vessel; b an oblong caisson of a semicircular section, suspended
at each end upon pivots in the deck beams, at the point c. The mast is stepped
in a trunk in this caisson, and secured by shrouds brought down to the sides of
the caisson, and by a fore-stay proceeding to the stern of the vessel, and by a
back-stay to the stern. The ballast is placed evenly in the bottom of the
caisson. Among the advantages claimed by Mr. Clint for this construction are,
first, perfect safety, as he considers it impossible a vessel can ever capsize.
Secondly, the vessel being always upright, is constantly on what are termed her
lines, and is always in trim, whereby she will sail faster and go better to wind-
ward; and lastly, that the ballast being suspended in air, is of more effect than


BOATS. 193
ballast placed in the bottom, Fig. 1.
which iaiter being identified
with the vessel in the water,
loses as much of its weight
as is equivalent to its bulk
of water, whilst the sus-
pended ballast retaining its
whole weight, a smaller
quantity will be required
to steady the mast, and the
vessel itself requiring none,
a great degree of buoyancy
is obtained. Mr. Clint con- C
structed a small vessel on (l
this fº and made a
regular series of experi-
ments during the summer
of 1825, in presence of a
number of scientific per-
sons, and officers and sea-
men of the navy, some of
whom accompanied him to
Gravesend, when it blew
fresh ; and from the great satisfaction given by its performances, the Society of
Arts voted Mr. Clint their large medal, or twenty guineas. This invention is
only intended for such vessels as are not employed in carrying cargoes, of which
class are revenue cutters, pleasure yachts, &c.; nor is it intended for vessels
above seventy tons, which may have the box decked in.
BOAT (LIFE). A boat invented by Mr. Henry Greathead, of South Shields,
for the purpose of preserving the lives of shipwrecked persons; and so well has
it answered, and indeed, exceeded, every expectation in the most tremendous
broken sea, that since its invention not fewer than 200 lives have been saved at the
entrance of the Tyne alone, which otherwise must have been lost; and in no
instance has it failed. The principle of this boat appears to have been suggested
by the following simple facts : Take a prolate spheroid and divide it into
quarters, in the line of its longer axis; each quarter is elliptical, and nearly
resembles the half of a wooden bowl, having a curvature with projecting ends;
this being thrown into the sea or broken water, cannot be upset, or lie with the
bottom upwards. The length of the boat is 30 feet, the breadth 10 feet, the
depth from the top of the gunwale to the lower part of the keel amidships, 3 feet
3 inches; from the gunwale to the platform within 2 feet 4 inches; from the
top of the sterns (both ends being alike) to the horizontal line of the bottom of
the keel 5 feet 9 inches. The sides from the under part of the gunwale along
the whole length of the regular shear extending 21 feet 6inches, are cased with
layers of cork to the depth of 1 foot 4 inches downwards, and the thickness at
the top 4 inches, projecting a little without the gunwale; the cork on the out-
side is secured with thin plate or slips of copper, and the boat is fastened with
copper nails. The thwarts or seats are five in number, double banked, that is,
two rowers sit upon each thwart, so that the boat can be rowed by ten oars.
The side oars are short, with iron tholes and rope grommets, so that the rower
can pull either way. The boat is steered by an oar at each end, and the steering
oar is one-third longer than the side oars. The platform along the bottom is
horizontal, the length of the midships, and elevated at the ends for the con-
venience of the steersman. The internal part of the boat next the sides, from
the under part of the thwarts down to the platform, is cased with cork, the
whole quantity of which affixed to the life-boat is nearly 7 cwt. The parti-
cular construction of this boat will be best understood by referring to the
engraving, Fig. 1 representing a cross section of the boat, and Fig. 2 a longi-
tudinal elevation. FF the outside coatings of cork; G G the inside cork
fittings; H H the outside planks of the boat; I I the stems; K the keel;
1


19 | BOATS.
N N timber heads; P the thwarts, or rowers' seats; R stanchion to support
the thwart; S section of a gang-board, which crosses the thwarts and forms
the passage from one end of the boat to the other. T the platform for the
rowers' feet; U U the two bilge pieces, nearly level with the keel; W W the
gunwales; X X ring bolts for the headfast, one at each end; Y platform for the
steersman; E E E the sheer or curve of the boat; L L the aprons, to strengthen
the stems; M M the sheets, or places for passengers; O O Othe tholes on which
the oars are hung by grommets. After the value of the invention was attested
by the presentation of a gold medallion to Mr. Greathead, by the Society of
Arts, as also one by the Royal Humane Society, and various gratuities in money,
parliament in 1802 unanimously voted him 1,200l. The Committee of Under-
writers at Lloyd's Coffee House, having voted Mr. Greathead 100 guineas,
appropriated 2000l. of their funds for the purpose of encouraging the building
of life-boats on different parts of the coasts of the kingdom. Great numbers
of these boats have since been constructed for all parts of our coasts, as well as
for those of foreign nations. . But as it most frequently happens that vessels
are wrecked on coasts where there are no life-boats, or that from the darkness
of the night or the strength of the wind and sea a life boat may not be able to
reach the vessel in time to afford succour, it is highly desirable that all vessels
should carry with them the means of safety for their crews; and accordingly
numerous plans have been suggested of converting the ordinary boats of a ship
into life-boats to meet these emergencies. Of these plans we select that of
Captain Henry Gordon as amongst the most simple and efficacious, whilst it in
nowise interferes with the ordinary services for which the boats may be required.
It consists in attaching to the exterior of the boat a species of buoy, of a trian-
gular form, which, whilst it adds greatly to the buoyancy of the boat, saves it
from concussions, offers little obstruction to its progress, and can be attached or
removed as occasion may require, with great facility and dispatch. Fig. 1 (page
195) shows the buoy; Fig.2 an end view of the same ; and Fig. 3 represents it
fitted to a boat. The buoy is composed of fine Spanish cork, and consists of
eight rows, each row being a foot longer than that immediately below it. Each
row is constructed of pieces of cork 1 foot long, 6 inches wide, and about
13 inch thick, laid three thicknesses together, and then placed end to end till
of the required length, (which in the drawing is represented at nine feet for the
upper streak,) and then formed into one streak by lengths of split bamboo,
laid on all four sides, and well sewed together by strong cord covered with shoe-
maker's wax. The different streaks are fastened together by four ropes, which
are seized together between each streak; when used, the ends are drawn under
the keel till the lower streak touches it, and then brought up over the side and
fastened to the thwarts; the other triangle is in like manner drawn up under
the boat's bottom on the opposite side and fastened. Two buoys to the scale of
that shown in the engraving contain 144 cubic feet of water; and if attached
to a boat 28 feet long, and capable of containing twenty-four men, would leave
a buoyancy of 718 lbs. for their support. Large boats, such as those capable

BOILERS. 195
of containing 100 men, instead of a single large triangle on each side, should
have three of 9 feet iengih each, by which ineans the same triangles might be
made to serve boats of different sizes, by which the expenses of outfit would be
materially reduced, and triangles of the above dimensions would also be more
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manageable, easier put on or taken off, and more easily stowed away than large
ones. Thus the launch, rowing twenty-four oars, with seventy-five men on
board, might be fitted in the following manner : the barge's triangle fixed
amidships, the cutter's on the bow, and the jolly boat's on the quarter; the
launch would then be rendered completely buoyant without any additional
expense. The contrivance combines several advantages; it is extremely
simple, and offers the best security under similar circumstances; it is so reason-
able in its cost as to admit of every merchant vessel being supplied with it; and
not being a fixture, it can be at any time removed, so as to be no additional
weight when a boat is being hoisted in or out. It is particularly advantageous
for the preventive service, to approach vessels and visit them when no other
boat can; for a blow that would stave a boat, would not penetrate the triangle
owing to its elasticity. At sea, also, it might take up a drowning man in a gale
of wind, when no other boat could live.
BOILER, in its most extended sense, implies any vessel employed for pro-
ducing the ebullition of liquids; thus the ordinary domestic pots and kettles,
brewing and washing coppers, as well as all kinds of vessels used for heating liquids
in various manufacturing operations, come under this denomination. Our business
in this place is, however, the description of that important apparatus wherein
is generated the source of that power which is regulated and applied by the
steam engine; previous to which, we shall make a few observations on the
requisite properties of steam boilers in general. The first and most important
quality we consider to be safety from explosion, for unless this be attained, so
as to render personal dangér improbable, such boilers should not be used at all.














196 BOILERS.
The next in importance is effectiveness, or that which will produce the required
quantity of steam by the consumption of the least quantity of fuel. , Cheapness
in the cost of construction, and durability in the wear, may be ranked as the
third requisite. The fourth is, perhaps, convenience, or that which can be worked
with the utmost facility, that will require the least personal attention, and will
occupy the least space. That boiler which combines the four qualities just
mentioned, and possesses each in the most eminent degree, may be deemed a
perfect one. The materials principally used at present for the construction of
boilers are iron and copper, though boilers have been made of wood and stone.
In those formed of wood the furnace was of necessity placed internally, sur-
rounded by the water; and as wood is an extremely bad conductor of heat,
but little loss of it was sustained by radiation therefrom, while a considerable
economy of fuel was consequently effected. The cost of such was also small,
compared to those of metal; they were introduced in America by Chancellor
Livingstone and Mr Anderson. Boilers of stone were introduced by Mr. Brindley,
who, in 1756, erected a steam engine near Newcastle-under-Lyne, with a boiler
of this description. It was composed of brick and stone firmly cemented
together, and the water was heated by iron flues. The material of which a
boiler is constructed is of more consequence, in an economical point of view, than
is usually supposed, as the heat cannot be communicated to the water without
being first transmitted through the substance of which it is formed. M. Despretz,
who made a series of very accurate experiments to determine the comparative
power of differentsubstances for conducting heat, obtained the following results:—
Gold . . . . . . . . . . . . . . . . . . . . 1000.0
Silver . . . . . . . . . . © tº º e º e e . . . 973.0
Platina . . . . . . . . Q & © e º e º e º e e 981.0
Copper . . . . . . . º es e º º e & . . . . . 898.2
Iron . . . . . . . . . . . . . . . . . . . . 374.3
Zinc . . . . . . . . . . . . . . . . . . . . 363.0
Tin . . . . . . . . . . . . . . . . . . . . . 803.9
Lead . . . . . . . . . . . . . . . . . . . . 179.6
Marble . . . . . . . . . . . . . . . . . . 23.6
Porcelain . . . . . . . . . . . . . . . . . 12.2
Fire bricks . . . . . . . . . . . . . . . . . 11.4
The conducting power of copper being thus more than double that of iron, offers
very great advantages; but there are other considerations to be entered into
before determining to which the preference is due, especially their comparative
cohesive strength and cost. According to some experiments the copper was found to
be the strongest, but that was probably owing to the iron being of inferior quality,
as most philosophers have agreed in attributing superior cohesive strength to
iron. Notwithstanding this circumstance, from the greater uniformity of the
texture of sheet copper over that of iron, manufacturers usually construct copper
boilers of thinner plates than those of iron, that have to withstand the same
pressure of steam. Experience has, we believe, established this as a rule, pro-
bably from observing that when a copper boiler bursts, it only tears open, while
a boiler of wrought iron plates is often blown to pieces. The cost of copper is,
however, four times that of iron; but if it be admitted that the quantity of heat
passing through iron in a given time can be doubled in copper, it follows that
a copper boiler having only half the superficies of one of iron, exposed to the
action of the fire, will be adequate to the generation of the same quantity or
force of steam. This circumstance, therefore, greatly reduces the weight of the
copper boiler, and, consequently, its first cost is made to approximate more to
that of the iron boiler of double the size. Increased strength is likewise acquired
by the reduced dimensions of the copper boiler, so as to permit of a decrease of
the pre-supposed thickness of metal; and thus the greatly enhanced price
per pound of a copper boiler over that of an iron one, which alarms many steam
engine proprietors from ordering them, is very much disproportioned to the cost
of the entire vessel. When an iron boiler is worn out, the old metal is scarcely
worth the expense of removal; but when one of copper is decayed, the old

BOILERS. 197
metal is worth three-fourths of its original cost. These considerations, together
with the increased safety and reduced buik of copper boilers, inciines us to
believe that in a course of years their use will be found more economical than
those of iron. In the construction of boilers of the ordinary form (that is, such
as consist of a capacious single chamber), the bottom surface should be of suffi-
cient extent to be capable of absorbing as much heat as will be necessary to pro-
duce the required quantity of steam, what little heat may be given out laterally
serving to prevent condensation in the upper part of the vessel; and the smoke,
before it enters the chimney, should be robbed as much as possible of its heat by
being brought into contact with the conduit pipe, by which the boiler is supplied
with cold water. It has been stated by a scientific authority that there is a con-
siderable waste of fuel in producing steam by intensity of heat upon a small
surface, and that the application of a moderate heat (8000 Fahr.) is far more
economical. A cubic foot of water converted into steam per hour was reckoned
by Mr. Watt as equivalent to one horse's power, who observed that this quantity
of steam could be raised per hour by 8 feet of surface of boiler and flue, in a
judiciously constructed furnace. In practice, it is usual to allow from 4 to 5 feet
of bottom surface of boiler to raise 1 cubic foot of water into steam per hour.
It is considered essential that a boiler should contain four or five times as much
water as it boils off per hour; and it is obvious that it should have a space above
the water capable of containing as much steam as will supply the engine at each
stroke, without materially diminishing its elastic force. For this purpose, the steam
room (or space above the water) should hold a volume equal to the supply of eight
or ten strokes of the engine : in large engines it is not unusual to employ two,
three, or more boilers, to supply them with steam; one of them being reserved for
use, in case of repairs being required to the others. In fact, a spare boiler
should be provided wherever stoppages are of serious importance in a concern.
The strength of low-pressure boilers should be twice the regulated pressure on
the safety-valve; but high-pressure boilers should be proved to at least three
times their working pressure. Upon the form of boilers much of their strength
and their efficacy in the generation of steam depend. The earliest boilers
employed for generating steam, and applied as a motive force, with which we are
acquainted, were either globular or hemispherical, with flat or concave bottoms;
and many of these are still in use for the supply of high-pressure engines. In
situations where fuel is so abundant as to render needless any economy of it,
they may continue to be used with advantage, as their form adapts them to
withstand steam of great elastic force. The waste of fuel caused by them,
elsewhere, led to avery general substitution of boilers of an oblong form; and those
known by the term of “waggon boilers,” from their shape, formed one of the
many improvements of the steam engine introduced by Watt. A longitudinal
section of a boiler of this kind is represented by Fig. 1 in the subjoined engraving,
fitted up with all the appendages now generally applied, and set in a furnace of
the usual construction. a a a is the boiler, having a cylindrical return flue b
throughout its length; the form of these parts will be best understood by con-
sidering them with reference to Fig. 2, which shows the figure of the boiler in
its cross section, b being the return flue; this portion of the boiler should be
always placed near to the bottom, and be constantly kept covered with the water, as
seen at c in the drawing. The flame and smoke from the furnace d first passes
under the boiler, then returns through the flue b to the front, where the current
is divided, and passing to the right and left through lateral flues in the brick-
work (one of which is brought into view at e e) before it enters the chimney ff.
The water is supplied to the boiler by the feed-pipeg, which is made to contain
a column of water equal to the amount of pressure in the boiler. On the top of
this pipe is a cistern h; i is a float, made of stone, suspended by a wire passing
through a stuffing-box j, which is attached to one extremity of a lever, whose
fulcrum is at k, a weight l being suspended to the extremity of the other arm
of the lever sufficient to counterbalance the difference between the specific gravity
of the stone and the water, causing the former to lie on the surface of the latter.
By this arrangement, when the water sinks below the proper level in the boiler,
the stone float descends with it, causing the attached wire to operate upon the
C C
*
198 BOILERS.
lever above, and lift the valve shown in the cistern h, which then affords a fresh
supply of water. The feed pipe likewise contains an iron bucket, hung by a
chain that passes over two pulleys o o ; the other end of the chain is attached
to a plate of iron p, called the damper, which is used to enlarge or contract, and,
ºf Zſº Fig. 1.
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when required, entirely close the throat of the chimney. By this contrivance,
when the steam in the boiler is urged to too great an extent, its pressure forces
the water in the feed pipe upwards, thereby raising the bucket m, and causing
its counterbalance, the damper, to descend in the throat of the chimney, and
reduce the intensity of the fire. At q and r are two guage-cocks, by which the
proper height of the water in the boiler may be always ascertained. If q dis-
charges water, and r steam, the water is at the proper height; if both cocks
discharge water, it is above its proper height; and if both discharge steam, it
is below its proper height. This latter circumstance, which can only take place
by the defective action of the last described apparatus, is of serious moment,
and requires an immediate remedy; the most safe is, in our opinion, the reduction
of the fire, by stopping up, by the readiest means at hand, all access of air to
the grate, after which, attention may be paid with confidence to removing the
cause of the defect. For the purpose of showing at all times the pressure acting
upon the boiler, a steam-guage is employed. This is usually made of an iron
tube, bent into the form represented, one end communicating with the steam-
room of the boiler, and the other open to the atmosphere. This tube is partly
filled with mercury, and into the externally open end is put a slight rod of wood,
which floats perpendicularly in the mercury, and shows by its altitude, on a
divided scale of inches affixed to that leg of the tube, the pressure of the steam.
If the steam raises the mercury or rod one inch, it proves that the pressure is
one half pound per square inch on the internal surface of the boiler, tending to
burstit; for if the section of the bore of the pipe was just one inch, the pressure
would be supporting one cubic inch of mercury, which will be found to weigh
nearly half a pound; therefore, for every two inches rise, one pound pressure
N



















































BOILERS. 199
imay be reckoned; and as condensing engines seldom work with more than
three or four pounds pressure upon the iiich, the scale ileed uot be longer thai,
eight or nine inches For preventing the pressure becoming greater than the
boiler is calculated to sustain without incurring danger, a safety-valve u is pro-
vided. This is usually a circular piece of metal, with a conical periphery ground
to fit into a conical seat, and kept there by the pressure of a lever, loaded with,
a determinate weight, that will not suffer it to rise until the steam has acquired
an excess of force above that required for working the engine, or would endanger
the bursting of the boiler. In large boilers, especially those in steam boats, it
is usual to have another safety valve, inclosed in a box under lock, the key being
kept by the chief manager, to prevent the possibility of improper interference
with it, by ignorant or imprudent persons: by the neglect of which precaution
many serious accidents have occurred. The steam which escapes from
safety valves is generally conducted by a pipe from the valve boxes into the
chimney. At v v is the steam-pipe by which the engine is supplied, the quantity
being regulated by a throttle-valve at w, and a screw-down valve at w. For the
purpose of cleaning out or examining the condition of the boiler, a circular or
oval hole y is made sufficiently large to admit a man to pass through, and
therefore called the man-hole. It is covered by a strong plate of iron bolted
down, in which plate is usually fitted the atmospheric or vacuum safety valve z,
which opens inwards by the pressure of the atmosphere, preventing the latter
force from injuring the boiler, should a vacuum be formed by condensation
within. A cock and pipe leading from the bottom of the boiler is employed
for discharging it of its contents. Next to the waggon-shaped boilers of Watt,
those of a long cylindrical form have been the most extensively employed,
especially for high-pressure engines, on account of their superior strength ;
besides as affording a considerable surface for the direct action of the fire and
heated gases. They are usually known in this country by the term “Trevithick
boilers,” from the supposition that Mr. Trevithick was the inventor. We, how-
ever, observe, that Mr. Oliver Evans, of America, describes them as being used
by him in his high-pressure engine, prior to the patents of Mr. Trevithick, and
as Mr. Evans does not claim them, we may suppose they were in use before his
time. Cylindrical boilers are
frequently made of a great
length, ten, twelve, or more
times their diameter, and are
preferable of such proportions,
where their situation will admit
of it, for the reasons before
mentioned. In this country
their extremities are usually
made hemispherical; but in
America the ends are usually
closed by flanged disks of great
thickness, on account, we sup-
pose, of the greater facility
of construction by ordinary
workmen. These boilers are
generally provided with an in-
ternal flue, through which the
heated air and flames, after tra-
versing the length of the under
side of the boiler, pass before
entering the chimney. The
annexed diagram represents a
transverse section of a small
high-pressure cylindrical boiler,
as manufactured by Mr. Saun-
ders, late of Sheffield, but now
of New York, U.S. The furnace

200 {30 I LERS.
door is at a ; b the furnace; c the ash pit; d the boiler; e the stone float (shown
by dotted lines), for regulating the supply of water, by means of the counterpoise
g; f is the internal flue, which returns the flame and heated air through the
boiler; h the steam pipe leading to the engine.
The boiler figured in the annexed cut, is of a cylindrical figure in the lower
part, but combines some peculiarities that are deserving of notice. It is a
patented arrangement by Messrs. Horton and Fisher, who are large boiler
manufacturers, near Birmingham. The object of it is to form a reservoir of
steam within the boiler, surrounded by the hot water, in order that the pressure
of the steam may not be reduced by radiation, which the inventors presume to
be the case in a greater degree in boilers of the ordinary construction. Fig. 1
Z
represents a longitudinal section of the boiler, and Fig. 2 a transverse section
of the same: the letters of reference apply to similar parts in each view. a a a
shows the external form around which the furnace and flues are to be con-
structed; b b b is the internal vessel or reservoir, for containing the steam
generated, surrounded by the water which is supplied by the tube o 0 from
another reservoir placed above, but not introduced into the drawing. The heat
having caused the steam to fill the upper part of the boiler d, it passes thence
through the bent tube c into the steam reservoir b below, from whence it is con-
ducted to the engine by the steam pipe e, the top of which n is designed for
the situation of the safety valve. At f is a cock for drawing off whatever water
may be condensed in the steam chamber, and at k may be placed another for
discharging the boiler. At l l are man-holes for gaining access into the interior.
We do not ourselves perceive how the intention of the patentees to make the
internal vessel b b a store of high steam for the supply of the engine, can be
effected by this arrangement, for the hottest steam will be rather disposed to
obey the laws of nature, and ascend into the upper vessel through the bent tube,
than descend through the same to the lower vessel, according to the desire of the
contrivers. It must, however, be admitted that there is a considerable degree of
originality in this boiler, and it may prove a useful and effective generator of steam.
In 1803, Mr. Woolf patented his boiler, which has obtained much deserved
celebrity. It has been for many years very extensively and successfully employed
in Cornwall, for the production of steam for the large mining engines there.
We have already observed that the long cylindrical boilers possess great advan-
tages over those of a cubiform or rotund figure. To increase their safety, and
their capability of producing steam at very high pressures, Mr. Woolf greatly
extended the principle of the cylindrical form. One of the most simple of this
gentleman's construction consists of eight tubes of cast iron (of six or more
inches in diameter), connected to each other by a bent tube at their extremities,
with communications to a larger cylinder above them, employed as a reservoir
for the steam. The furnace is divided by a wall longitudinally into two parts,
and the eight tubes are fixed horizontally across both these. The fuel chamber
is at one extremity of one of the divisions, and arched above the two first tuhes.

BOI LERS. 201
so as to reverberate the flames and heated vapours, which then pass under the
4l-3-3 4-1-2, --- ~ 4 tº a £-----|- ºr A ov, *k, a £4%l- or ov. 4-ko eviv 44, --~~~l ov. 4-kº r → ~~~~~4.1-
* A A 1.1, W.A. vu ºv; v v v. A. viav as us a vaay “a a “*** was º as a vaay v v - a vaa." ~ a2-vs.-3 *.*, L.A. V.4 ºf a º A^* •v v van was 9
and partly over and partly under the eighth tube, when the flue turns into the
second division of the furnace, on the other side of the wall, built under, and
in the direction of, the large steam cylinder before mentioned. Passing now
under the seventh cylinder, the course of the flue is over the sixth, under the
fifth, over the fourth, under the third, over the second, and partly over and
partly under the first, when it enters the chimney. To produce this long ser.
pentine reverberation, the upper and under side of the brick-work is formed in
arches, alternately reversed, their extremities abutting against the tubes, covering
about a sixth part of their circumferences, but exposing the rest to the action
of the current of heated matters from the fire. Each of the tubes is provided
with a flanged disk at one end, fastened on by screw bolts, that they may be
easily removed, and the tubes cleaned out at pleasure from sediment and in-
crustations. The water carried off by evaporation is replaced by the usual
means of a force pump, and the steam generaved is conducted to the engine or
other object, by a tube connected to the steam reservoir. “It may not be irr.
proper,” says Mr. Woolf, “to call the attention of those who may hereafter wish
to construct such apparatus, to one circumstance: namely, that in every case,
the tubes composing the boiler should be so combined and arranged, and º, e.
furnace so constructed, as to make the fire, the flame, and the heated air, to act
around, over, and among, the tubes, embracing the largest possible quantity ºf
their surface. It must be obvious to any one that the tubes may be made of
any kind of metal; but I prefer cast iron as the most convenient. The size of
the tubes may be varied; but in every case care should be taken not to make
their diameter too great; and it must be remembered, that the larger the
diameter of any single tube in such a boiler, the stronger it must be made in
proportion, to enable it to bear the same expansive force as the smaller cylinders.”
Mr. Woolf also directs that the lower tubes should be always kept filled, and
the upper, or steam cylinders, half filled with water, that is, as high as the fire
is allowed to reach, and that in no case the water ought to be allowed to get so low
as not to keep full the branches which join the lower tubes to the upper cylinder.
The annexed engraving exhibits an arrangement of parts combining the
leading features of several previous inventions, and was patented by Mr. Thomas
Tippet, of Gwennap, in Cornwall, in 1828. Fig. 1 represents an end view, and
Fig 1. Fig. 2.
ſ sº-º-º-º-º:
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a - a W º
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iſſiº
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Lº
Fig.2 a side view of the boiler; the same letters of reference in each indicating
similar parts. a is a large cylindrical boiler, containing an internal cylinder,
which constitutes the fire place and principal flue. From the external cylinder,
which contains water, proceed three rows of open vertical pipes b b b, which
support a semi-cylindrical steam vessel c. At the farthest extremity of the
cylinder a there proceeds horizontally a short open pipe d, communicating with
a small supplementary boiler, which is a cylinder of the same area as a, but
very short. This boiler is built in a furnace, in which the flues are so arranged
that the heated air, in passing out at the end f of the furnace flue, shall impinge
against the flat side of the supplementary boiler; the flue thence proceeds
upwards, and along the underneath flat side of the semi-cylindrical vessel,
§



















202 BOILERS.
between the vertical tubes to the front of the boiler, where it descends, passing
under the bottom of the latter, then round the back of the supplementary boiler,
and over the top of the semi-cylinder to the chimney, which is in front, nearly
over the furnace doors.
An ingenious attempt to expose water in thin sheets over an extended surface
of metal, was made by Mr. John M’Curdy, from the United States, who patented
it in this country. It consisted of a series of cylinders, with spherical ends,
arranged horizontally like retorts, in a pyramidal form, in a furnace, so as to
cause the heat as much as possible to impinge against their surfaces, in its
ascent amongst them to the flue above. Each of these cylinders contained
within it another cylinder, of so much less diameter than the outer, as to leave
between them throughout a very narrow space, the uniformity of which space
was preserved by coiling a spiral band upon the outside of the inner cylinder, or
other suitable contrivance. These latter cylinders were hermetically closed at each
of their ends, and were placed inside the former to produce between them hollow
cylindrical sheets of water. The water was forced into one of the lower cylinders,
and made, by the action of the pump, to circulate through the others of the
series. By this arrangement of disposing the water in thin sheets, it was pre-
sumed that steam of a very high pressure would be generated with extraordinary
rapidity. We have, however, never been informed of the cause of this boiler
not having been brought into practical operation, and are therefore left to con-
jecture that it was probably owing to the great expense of construction; the
liability to deposits and incrustations in the narrow spaces between the internal
and external cylinders; the difficulty of cleansing them; and, by the neglect of
the latter operation, causing an irregular generation of steam, the heating red
hot the incrusted parts, and, as a consequence, the blowing out of the water,
and the rapid destruction of the metal. To these causes may be added the
waste of fuel by the shortness of the flue. The contrivance is, nevertheless, not
devoid of merit, and may afford a useful hint to succeeding inventors. The
superior strength and safety of boilers made of small tubes have within the last
few years led to their introduction in almost every possible variety of form, a great
many of which have been the subjects of unproductive patents. Those which
possess the most distinct character from each other, and have been more or less
brought into public use, we shall proceed to notice.
The first we shall describe is the invention of Mr. W. H. James, patented
in 1823. It consisted of a series of annular tubes of equal capacity and
diameter, placed side by side, and bolted together, so as to form by their union
a long cylindrical boiler, in the centre of which, at one end, the fire-place was
situated. The tubes were made of the toughest wrought iron, three sixteenths
of an inch thick; and being of only one inch in diameter, they were capable,
as was proved, of sustaining a pressure of several thousand pounds per inch.
In some of these boilers, the tubes were made square in their transverse section,
consequently, when their flat sides were placed together as described, there
were no open spaces between them; and the annular tubes were connected
together by means of long bolts passing through the end-plates of the cylinder,
where they were screwed up firmly by nuts on the outside. Communications
from tube to tube were made by making two perforations in them lengthways
of the cylinder; one on the upper side, for the free passage of the steam, and
one on the lower, for the flow of the water. When it was desired to construct a
boiler of greater power in a compact form, to adapt it more particularly to loco-
motion, Mr. James preferred making two concentric cylinders, each composed
of a series of annular tubes, like those described, and as delineated in the
annexed diagram, which exhibits a transverse section of such a boiler. The
annular tubes are distinguished by the water drawn therein. The upper per-
forations or steam passages are shown at b b, and the lower, or water passages,
at c c. The water was maintained at the desired level by the action of a
float, in an adjoining vessel, not shown in the figure. The furnace bars formed
two inclined planes, as shewn, at one end of the cylinders, and the flue
descended at the other end. These latter parts were made so as to be easily
detached at pleasure. The entire boiler turned upon an axis, and rested upon
BOILERS. 2()3
rollers, fixed in a circular stand; every tube was furnished with some shot,
mixed with angular pieces of ineiai, so that when it was desired to cleanse the
boiler of deposit, the furnace and chimney tube were drawn out, the con-
necting pipes unscrewed, when the cylinder was turned round by a winch, in
wº
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the manner of the common scouring barrel, used for brightening metallic articles.
To prevent the loss of heat by radiation, the boiler was surrounded by a double
case, the spaces between which were filled up with a mixture of clay and char-
coal. We have repeatedly seen a boiler of Mr. James's construction, on the
principle of the last described, but consisting of only one cylinder of annular
tubes, 3 feet 6 inches long, and 20 inches diameter, effectively working a very
small high pressure engine, (having only a 3 inch piston of 12 inch stroke,) up to
three horses' power. This boiler had circular tubes, and each annulus was made
out of two semicircular pieces, connected at their extremities to an upper and
a lower transverse horizontal tube, the length of the cylinder; the upper one
forming the principal and the connecting steam tube, and the lower one the
water tube. Into these horizontal tubes, conical perforations were drilled, to
receive the extremities of the semicircular tubes to which they were united,
steam and water tight, by means of bolts and rivetted keys. However firm
this mode of uniting appeared to the eye, and however accurate the workman-
ship, when the fire came to act upon the joints they often became leaky, and
were the source of great trouble and inconvenience. Since the period alluded
to, Mr. James has invented another boiler, to which he gives the preference,
and will be described under the article STEAM. Before, however, we quit this
part of the subject, we would draw the reader's attention to the circumstance of
the steam chambers in Mr. James's boiler, as shewn in the preceding engraving,
by which it is evident that the surfaces of the water are pressed upon by the
steam, and that the latter derives an increase of heat and of elasticity subsequently
to its formation, by the action of the most intense part of the fire; consequently
it would appear that this arrangement is eminently calculated to prevent, the
water rising, or being forced over into the engine; an inconvenience which
had been experienced in most boilers made of small tubes. Although the in-
convenience never occurred in Mr James's boilers whilst the fire was kept
steady, the supply of water regular, and the tubes clean; yet from the neglect










































204 BOI LERS.
or failure of some one of these conditions, the water did occasionally coma
over. The observations we have been enabled to make upon these facts, incline
us to the opinion that it would be better not to make boilers of tubes of a less
diameter than two inches; because the much larger body of water such contain
are not so suddenly and violently affected by ordinary variations of temperature
occasioned by unskilful firing, or by the irregular supply of water; nor are the
tubes so liable to become choked, as the joints can be made with greater
accuracy without filling up the water or steam way, to the danger of the tubes
becoming red-hot, and the destruction of the boiler. Tubes of two inches can
be much more easily cleansed; and as respects safety, it is scarcely possible to
burst them, if only a quarter of an inch thick, by any pressure of steam that
can be beneficially applied.
The contrivance we shall next notice is the invention of Mr. Goldsworthy
Gurney, a gentleman of the medical profession, but more generally known to
the public by his persevering attempts for the establishment of steam carriages
on the common road; and the boiler we shall describe is especially designed for
T i
ºilitiºnſ." iſiºn
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i
iſſiº
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ſº-º-º-º-º-º-º- *-*-* º . . .
Tº T
that purpose. Fig. 1 shows a vertical section of the boiler. Fig. 2, an ex-
ternal end view of the same. Fig. 3, the manner in which the series of pipes
composing the boiler are fixed, and open into horizontal chambers. Fig. 4, a
portion of one of the horizontal chambers, partly broken away to exhibit the
apertures of the pipes, and their arrangement. The same letters on each
figure refer to corresponding parts. In the section Fig. 1, the semi-elliptical
form in which the pipes are bent, and the manner in which they respectively
cross each other, is seen; the ends of these pipes have screw threads on the
outside, to receive nuts, which secure them to the horizontal chambers b, as
shown in Fig. 3; a packing composed of pounded asbestos, mixed with red lead
and litharge, in about equal parts, is interposed between the nuts and the end
plate, applied in hollow washers of a saucer-like form, which it is said makes
perfectly steam, water-tight, as well as fire-proof joints. The chambers b have

BOILERS. 205
direct communication one with another, by means of the vertical pipes c, d d,
are two beni iubes, leading from t t into the steam vessels or “separators’ e e
(as Mr. Gurney calls them.) From thirty to fifty, (according to the size of the
apparatus) of the small º a, are arranged in the manner shown in Figs. 1
and 4, in which the fuel is placed as at h, the heated air and flames being
directed by a bridge i, to take the course delineated before entering the
chimney k; but a considerable portion of the heat passes freely between and
round about the pipes, the whole of them being exposed to the powerful effects
of a furnace so circumstanced; o is the furnace door, and i the ash-pit. During
the working of the engine, the steam chambers e are by the usual means kept sup-
plied with water up to the level shewn, which being higher than the pipes in the
furnace, the latter are always kept full of water, as judiciously recommended by
Woolf in his specification, quoted in the preceding part of this article. The steam
generated in the small pipes ascends by its superior levity through the water in the
steam vessels e, or it may be, transmits its caloric to other particles of water, which
escape at the surface of the fluid in the form of vapour, which passes off through
the branches f f into a common pipe g, that leads to the engine. In fixed
engines the iron casing represented as surrounding the boiler is dispensed with,
the apparatus being set in the usual manner in brick-work. To obviate a com-
mon objection to tubular boilers, of their becoming choked with a deposition of
earthy matter, Mr. Gurney purposes to clean them out when they become foul,
by the following chemical treatment. If the tubes are of iron, one part of
muriatic acid, with 100 parts of water, are to be left in the boiler, a sufficient
time to dissolve the incrustations; if of copper, the following solution is to be
used in a similar way, one pound of common salt, half a pound of sulphuric
acid, in four gallons of water. To expedite the operation of cleansing, a small
fire may be made in the boiler, and the steam be employed to blow the contents
out of the tubes. One of the most prominent advantages attending the use of
this boiler, is the great facility with which repairs are executed; when a tube is
injured or burned, the removal of it or the substitution of a new one are only the
work of an hour. Like other tubular boilers, it is safe from the effects of rup-
ture; but the “separator” being in fact a steam reservoir, that part is as liable
to explosion as other boilers of the same capacity and thickness of metal. The
small tubes exposed to the fire, if always kept full of water, are not likely to be
soon burned out. The merit of this arrangement is however, due to Mr. Woolf,
(see page 201,) and were Mr. Gurney's steam reservoirs defended like that
gentleman's, from the © © C
cooling influence of the
atmosphere, the effect O ; : O
of their contents upon *
the engine would be
improved.
The annexed diagram
is explanatory of a boiler
which has been em-
ployed for the gene-
ration of steam in the
locomotive carriage of
Messrs. Summers and
Ogle, who have taken
out a patent for it. It
consists of a series of
tubes, placed vertically,
with a flue passing up
the centre of each; a a a represents the external tubes containing the water and
steam ; b b b the interior tubes or flues, for the passage of a portion of the heated
air, &c., the remainder passing off between the exterior tubes; and thus the water
of the boiler disposed in thin hollow cylinders is continually exposed to an extensive
surface of heated metal on both sides. c c c are the ends of the internal tubes
passing through the screwed nuts d dd at the top, and ee e at the bottom, and by
D D

206 "BOILERS.
which both the exterior and interior tubes are secured in their places. The water
is supplied to the boiler through the pipe f, by a force pump; and the steam when
generated, passes off to the engine, by the pipe i. Although the heated matters
from the fire have but a short passage to the chimney, it is obvious that the
obstruction to the current formed by so many tubes crowded together must be
considerable, and cause a great portion of the heat to be absorbed, it being, as it
were, wire-drawn. Economy of fuelis, however, not a matter of such important
consideration in a steam carriage, as in fixed engines; there being in the present
infant state of locomotion, on the common road, no competition. It is obvious
that the different parts of this boiler can be put together with facility, and that
a defective tube can be instantly removed, and a sound one substituted, by simply
unscrewing the interior flue or tube. The manufacture, however, requires the
utmost exactness, especially in making all the tubes of precisely the same
length, and the other parts corresponding with each other of uniform dimensions;
otherwise a source of imperfection would arise, from the longer tubes preventing
the shorter ones from being screwed sufficiently close to render them steam-tight.
Although the inventions of Mr. Jacob Perkins (who has distinguished himself
by numerous ingenious attempts to generate and work steam at pressures far
beyond that of any other experimentalist or engineer,) have not been attended
with that success which the public were led to believe, many of his arrange-
ments possess considerable merit, and ought to have a place in this work. We
allude in particular to his having brought steam of enormous pressure under
the most perfect control. The annexed diagram is explanatory of a boiler
#I.
Q.
employed by Mr. Perkins, which we saw working, a small engine, on the high
pressure and expansion principle, calculated by him at 30 horses' power. A
series of cast-iron bars, 5 inches square, perforated throughout longitudinally,

BOI LERS. 207
furnace, of sufficient length to come through the opposite walls, where their
extremities were connected together in a peculiar manner, so as to form one
continuous vessel. By the operation of a forcing pump water was continually
injected under the pressure of a heavily loaded valve into the two upper tiers
of tubes, so as to keep them always full; the third or lowest tier of tubes con-
tained no water, and were to be kept at a temperature of about 10000 Fahrenheit.
At each stroke of the engine, a certain quantity of the water contained in the
two upper tiers, (supposed to have acquired a temperature of 700° or 8000,) was
discharged into a valve box at C, communicating with the lowest tier of tubes
D, wherein it flashed into steam, and passing successively through those tubes,
exposed to the intensity of the fire, it was received into a steam chamber L for
the supply of the engine. The object of the inventor in introducing such great
masses of metal into his apparatus is not very apparent, unless it be the pre-
vention of sudden and great variations of temperature in the tubes, which
perhaps could not otherwise be effected, as the body of water they contain is
too small to maintain much uniformity of heat, and Mr. Perkins must be well
aware that the perfect safety of such generators is not increased by form-
ing them of a square figure instead of circular.
To obviate the destructive effects of the direct action of the fire upon the
substance of which a boiler is constructed, and by which action the liability to
rupture is increased, a great variety of plans have been projected. Three of these
plans, which appear to be deserving the attention of the reader, we shall subjoin.
The first is the invention of Mr. Aaron Manby, of Horsely, near Tipton, in
Staffordshire, for which he had a patent in the year 1821. It is well known
that oil and other fatty matters are capable of being raised in temperature far
above that of boiling water, without undergoing decomposition; this property in
oil having never before been applied to the working of a steam engine, formed
the groundwork of Mr. Manby's patent. The construction of his apparatus is
explained by the annexed diagram; where a represents an oblong boiler, sup-

208 BOILERS.
posed to be set in brickwork, over a fire-place of the usual construction. This
vessel is to contain the oil, which is to be heated to about 3000 Fahrenheit. The
vessel above b is a strong cylinder, containing the water to be converted into
steam, inside of which is fixed a system of pipes, connected into one continuous
line; through these pipes the oil is made to flow by the action of a pump at
c, (worked by the engine, or other first mover,) which raises it by the pipe d,
and discharges again into the boiler by the pipe e. The heated oil in its pas-
sage through the pipes elevates the temperature of the surrounding water, and
converts it into steam of several atmospheres' pressure. The patentee states,
that by this apparatus steam of very high pressure may be generated without
the possibility of danger, and that a smaller quantity of fuel is consumed than
when the fire operates in immediate contact with the water vessel. In what
manner, however, this economy is effected is not very apparent; and although
the danger of explosion in the steam vessel is considerably lessened, the liability
to accidental conflagration is so far increased by the contiguity of the furnace
to such an inflammable substance as oil, (which was liable also to become thick
and glutinous) as to render it imprudent to use the apparatus in buildings that
are not fire-proof.
The second invention we have to notice is that of Dr. Ernst Alban, a
physician of Rostock, in Germany, a patent for which was obtained in this
country in 1825. The heating medium is, in this case, such a mixture of tin
and lead as will remain in a fused state at the temperature required for the
steam, which is generated in small vertical tubes suspended in the bath of liquid
metal. The subjoined diagrams exhibit two baths of this kind connected
together, in each of which are deposited eight generating tubes. Fig. 1 shows
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a longitudinal section of one of the vessels, and Fig. 2 a transverse section of
both ; they are made of cast iron, in the form represented at a a q, b bindi-
cating the metallic mixture. Supported upon the cover of the metal vessel, 1S
a strong top c e of the generator, containing a cylindrical chamber of 2 inches
in diameter; d d d, are the wrought-iron generating tubes, suspended in the
metallic mixture; they are of is inch bore and are screwed into the top





































































































BOILERS. 209
c c, so that they may be taken out whenever they require cleaning; e is the
injection pipe, through which the water is conducted inte the generating tubes.
through a small perforation made over each. The double vessel, as best seen
in Fig. 2, is suspended in the furnace, so as to expose all its four sides and ends to
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the action of the fire; so that although it is but 4 feet long, 3 feet 6inches high, and
9 inches wide, it exposes a surface of 64 feet to the fire. The two injection
tubes are connected externally, and communicate in one pipe with the forcing
pump. This pump is of the usual construction, furnished with a lever and
weight, which are raised by the engine. If the production of steam in the
generators be too great for the wants of the engine, the pressure in the steam
chamber will act against the injection, and the weight will be insufficient to
force down the piston of the pump, which will thus remain inactive, until the
pressure is diminished by the ceasing of production and the expenditure of the
engine. To prevent the metallic fusion from being overheated, in cases where
a smaller supply of steam is required, or where a suspension of steam genera-
tion takes place, by the stoppage of the engine or otherwise, the inventor has
arranged a heat regulator, which governs the intensity of the fire. The apparatus
indicates the temperature of the fused metal, upon which solely its action
depends, and the generation of steam in the generators has no influence what-
ever upon it, the regulator continuing to act when the generation of steam has
ceased, on which account it appears to be essentially different from any heat
regulator previously used. Its application to this apparatus is indispensable, to
prevent such a heating of the generating tubes as might occasion a decompo-
sition of the water injected therein. It consists of two-pipes filled with atmo-
spheric air, one of each being inserted into each vessel, (Fig. 1, g) and
surrounded by the metallic medium. To both pipes, very narrow tubes are
fixed, shown at h, Fig. 1, and i, Fig. 3; these are joined externally into one
tube, which opens inside the mercurial cistern, a, Fig. 3. Within the mercury
therein contained is immersed a vertical tube b, with a float c-swimming on the
top of the mercury. This float is connected, by means of the rod d, with the
rode, and acts by the rod f upon the damper g, which regulates the draught of
the fire in the ash-hole. When the air in the pipes, Fig. 1, g g, becomes heated
by the fusion, it expands progressively as this becomes hotter, presses on the
mercury in a, Fig. 3, and causes it to ascend in the tube, b. By the rising of
the mercury, the float c is made to ascend likewise, and acts by the rod d on
the lever e, and thereby on the damper g, so that should the temperature of




210 BOILERS.
the fusion be greater than is required, it gradually closes the air-hole h, by
which the supply of air to the fire is prevented, and the heat consequently
diminished. Although the intelligent inventor of this apparatus was, as we are
informed, unsuccessful in the introduction of it, yet it has strong claims upon
the attention of engineers for the originality and ingenuity of many of its
arrangements. The employment of a fluid metal, possessing a high conducting
power, for the heating medium, instead of an inflammable substance like oil,
possessing but feeble conducting power, promised much better results, while it
rendered the use of the apparatus perfectly safe.
Mr. Porter, a scientific gentleman, who was connected with Dr. Alban in the
last described project, subsequently invented, in conjunction with Mr. Beale, an
engineer, the third plan we have alluded to. In this apparatus, the arrange-
ment is such as to render it impossible to impart a higher degree of heat to the
#. than the boiling point of the fluid employed as the medium, as the vapour
om the latter is allowed to escape as it is formed. The annexed figure affords a
longitudinal section of the apparatus; a a is the vapour chest, formed of thin plate
iron; b the generator, which this drawing may be considered as representing by
an edge view of a system or coil of wrought iron tubes; the dotted line c marks
the height of the fluid medium; d the “breathing-pipe,” which in the event of
injudicious firing, serves as an outlet and condenser, for such portion of the
vapour as may not otherwise be condensed by the lower temperature of the boiler;
e an ordinary furnace and flue; f, the ash-pit; g the chimney; h the supply pipe to
the generator, through which water is injected by means of a forcing pump, worked
by the engine; i is the steam pipe communicating with the engine. The water
injected through the supply pipe h being exposed, during its progress through
the generator, to the heat of the vapour furnished by the boiling fluid under-
neath, is thereby converted into steam, with a temperature and elastic force
answering to the temperature of the vapour, which, losing a portion of its
heat, resumes the liquid form, and falls to the bottom of the chest a, while the
partial vacuum formed by its condensation causes a fresh portion of vapour to
supply the void, and thus keep up a constant action. It is manifest that the
temperature of the steam must be uniform, and that no greater degree can be
communicated than the boiling point of the fluid medium chosen, and all
injury to the machinery is therefore avoided, while, from the same cause, all those
sudden accessions of elastic force, which have frequently proved so disastrous,
are rendered impossible. This mode of heating has, we are informed, been
very successfully employed in the preparation of vegetable extracts, and in other
chemical operations where regulated degrees of heat are essential. As respects

BOILERS. 211
its application to the generation of steam for engines, we are not aware of its
having been so used by any other persons besides the patentees. Objections have
probably been raised to the combustible media employed in the vapour chest, and
the expense attending the supplying the loss of it occasioned by evaporation.
These media were chiefly the spirit of turpentine, naphtha, naphthaline, and
other products of coal tar, forming a variety of mixtures, whose boiling points
vary from 2009 to 7000 Fahrenheit.
In the former part of this article, we have had occasion to notice the incon-
venience arising from the deposit in boilers, and to mention some of the modes
adopted for cleansing them. Occasionally these deposits are several inches in
thickness, and as hard as the artificial stone pottery, caused by the baking they
receive while in contact with the metal of the boiler, which receives the direct
action of the fire. To remove these incrustations is a work of considerable
labour; it being a general practice for workmen to get inside the boilers, and
break up the stony matter, by means of heavy hammers and cold chisels.
These deposits are also the cause of other serious inconveniences; they form
a non-conducting shield between the fire and the water, rendering the boiler
liable to become red-hot, by which its destruction or premature wearing out is
effected, and a considerable waste of fuel is made. To obviate these injurious
tendencies, a variety of plans have been proposed. Some engineers throw into
the boiler a quantity of some fibrous and mucilaginous vegetable matter, such
as bran or husks, to which the earthy matter in the water adheres, and is
thereby prevented from becoming concrete and hard, and consequently more
easy to be removed.
In the year 1828, Mr. Anthony Scott, of the Southwark Pottery, Durham,
took a patent for a very obvious and effective contrivance to abate this evil.
His plan is to place a number of slabs or trays of metal stone or wood near to
the bottom of the boiler, which it is said so reduces the agitation of the water
during the ebullition, that nearly the whole of the sediment descends by its own
gravity, and deposits itself in the trays, instead of on the bottom of the boiler.
The transmission of the heat is not intercepted by this arrangement, while the
trays are removable at pleasure, for clearing them of the sediment deposited
upon them.
More recently, (in 1830,) Mr. William Taylor, of Wednesbury, took out a
patent, having for one of its leading objects the prevention of the incrustation
and removal of the sediment, without stopping the operation of the boiler. It
consists of a sediment trough or vessel, extending the whole length of the
boiler, immediately under it, with a valve opening at one end, through which a
portion of water is occasionally permitted to escape with great velocity, arising
from the pressure of the steam, that it may carry with it whatever deposit may
have settled in the bottom. This arrangement is represented in the annexed
sketch; a a is a cylindrical boiler, having a
fire place b, and a flue within it; c is the
deposit vessel below the fire. When this in-
vention is applied to boilers which have the
fire under, instead of inside them, the patentee || ||
applies a deposit trough on each side, and these
must be shielded from the action of the fire.
The claim to invention under this patent is
limited to the particular modifications de-
scribed; as deposit vessels have, before the
date of Mr. Taylor's patent, been applied to
boilers; and they are undoubtedly appendages
of great utility. On account of the great deposition of salts, and other earthy
matters, on the bottom and sides of boilers employed in steam boats at sea, it
becomes expedient, in long voyages, to stop the progress of the vessel, in order
to discharge the contents of the boilers, and fill them anew ; for if the heat be
continued after a considerable deposition has taken place, the steam can only
be raised by a greatly increased expenditure of fuel, and the augmentation of
the heat materially injures the tenacity of the metal of which the boilers are

212 BOI LERS.
composed. To obviate so great an inconvenience, Messrs. Maudslay and
Field have proposed an arrangement of apparatus, by which the water is con-
tinually being changed, and for which they took out letters patent in 1824.
These gentlemen state that from 20 to 30 per cent. of the quantity of water
evaporated, being taken from the concentrated brine, will keep the water within
a degree of saltness from which no practical evils will result, however long the
boiling be continued; the quantity thus abstracted from the boiler being of
course replaced by a like quantity of sea-water in its natural state. The abstrac-
tion of the brine is made by means of a small pump, with a loaded discharge
valve, worked by the engine, and so proportioned as to draw from the lowest
part of the boiler the quantity determined on, which may be regulated by a
meter, shewing the quantity of water driven off in the form of steam. The
operation of the pump is, however, not to commence until the brine has attained
a considerable degree of concentration; it should for instance contain five
times as much salt as common sea water does; after this, every stroke may
be made by means of the pump, to take as much salt out of the boiler as is
deposited in the boiler by the separation of the steam used in that stroke. By
these means, the water in the boiler can never exceed a certain predetermined
degree of saturation; and whether the engine be working quickly or slowly,
the quantity withdrawn may always be made to bear the same proportion to the
quantity left in, thus avoiding one of the greatest evils to which steam vessels
in making long voyages have been subjected. To economise the heat and con-
sequent expenditure of fuel, Messrs. Maudslay and Field further propose that
the hot brine extracted by the pump be discharged into a vessel containing a
series of metal pipes of small calibre, similar to a refrigeratory. Through these
pipes, which lie immersed in hot brine, the supply water is to be made to pass
in order to abstract the heat in its progress, and deliver the sea-water into the
boiler in a heated state.
In the year 1824, Mr. Smith introduced, in some of the salt works of Lan-
cashire, a mode of evaporating brine, by the application of high-pressure steam
under the salt pans; and as the surfaces of these vessels are very extensive, they
are incapable of sustaining much pressure. Mr. Smith, therefore, tied the
bottom of the boiler to the bottom of the pan (which also formed the top of the
boiler), by means of screw bolts and nuts, in the manner shewn at b in the sub-
joined sectional figure. Finding this arrangement productive of a safe and
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efficient generator of high pressure steam, he subsequently took out a patent
for a modification of it, to be applied to steam engines. This modification
chiefly consisted in the addition of the upper vessel a. The plan of these vessels
is supposed to be a parallelogram, and the screw bolts about 9 inches apart in
each tier, over their whole surfaces. The water is supplied by a force pump, as
represented, and a number of guage cocks are fixed at different elevations, as
shewn in the drawing, to ascertain the height of the water, and the state of the
steam in each vessel. e e are steam pipes; f is a safety valve to the lower
chamber b, and g another to the upper chamber a. The patentee states, that
“about two inches of water are put into the lower vessel, and the other being
half filled, the fire is lighted, which quickly raises the water in the lower vessel
to ebullition, the steam of which acts upon the lower surface of the upper boiler,
giving out its heat to the water contained therein, and is thereby itself condensed;



BOILERS. 213
and being thus alternately vapourized and condensed, the upper vessel is con-
verted into a stcam chamber of unifoi in temperature.” Although this boiler is
calculated to generate steam with rapidity, owing to the extensive surface of
metal exposed to the direct action of the fire; and notwithstanding it must be
deemed safer than most others of equal capacity and effect, by reason of the
numerous tie bolts; it must, we think, be expensive in construction, and very
difficult to preserve free from leakages.
In the generality of boilers the flue first takes a horizontal direction, more or
less extended, and afterwards ascends the chimney; sometimes it is also made
to descend; and in almost every way that ingenuity could devise, the flues have
been made to encompass the water, for the purpose of transmitting their heat
thereto. Mr. Joseph Gibbs, of Crayford, in Kent, has, however, invented a
boiler, (patented in 1830,) which possesses some claims to originality of arrange-
ment; and as it probably confers some advantages, we shall here notice it. The
form of the upper portion of this boiler is circular, with a descending cylindrical
branch of considerable magnitude and length, the latter being quite full of
water, and the upper filled to about four-fifths its depth, the remaining one-fifth
being reserved for steam room. In the middle of the upper vessel is the fire-
place, the air for combustion being supplied by a vertical pipe, passing upwards
through the descending cylindrical branch of the boiler. The products of com-
bustion first act upon the water in the upper vessel, whence the flue descends
in a curvilinear direction around the vertical air pipe in the midst of the water
contained in the descending branch of the boiler, to the bottom thereof, and
thence into the chimney. For the ready passage of the smoke, a temporary
flue, which proceeds in a direct line to the chimney, is opened whilst lighting
the fire, after which it is stopped by a damper or valve, which causes the current
of heated matters to take the descending course described. By this arrange-
ment, Mr. Gibbs extracts the gaseous products of the fuel, till they are reduced
to nearly the temperature of cold water, the supply water being introduced
where the flue terminates. In the specification of this patent, Mr. Gibbs has
also represented a long cylindrical boiler, placed horizontally, with three
descending branches, and another with a flue in a zigzag direction, through
the descending part of the boiler, which, although it has the advantage over
the others of being of more easy manufacture, is not so favourable to the
descent of the current. The partial action, owing to the unequal distribution
of heat upon the different parts of a boiler, it was long since observed had a
tendency to produce circulating currents of water throughout the vessel. This
motion of the fluid has of late years been deemed of so much importance in
the economical generation of steam, as to have induced several engineers to
obtain patent privileges for their schemes: amongst these, Mr. Jacob Perkins
is most conspicuous, for having taken out two patents for the same object, one
in 1831, and the other in 1832. But as nature is inclined to perform the cir-
culatory process pretty well without the assistance of art, we shall dismiss the
subject with a brief notice of the above-mentioned gentleman's plans. In the
first of these, Mr. Perkins placed a thin metallic lining inside of the boiler, at a
small distance from the bottom and sides, but leaving an opening in the lining
at the bottom, where the heat of the fire is the strongest. Here, therefore, the
water will acquire the greatest levity, and consequently ascend, while the water
next to it, which is that between the lining and sides of the boiler, will occupy
the bottom of the rising column, and thus a constant circulation will be kept up
through the whole of the fluid in the vessel. In Mr. Perkins's second patent,
which is stated to be for improvement on his former one, the aforesaid linings
are to be augmented so as to cover a more extended surface, and form *
a complete internal vessel at a few inches distance from the external one. It
would require a large volume to describe the multiplicity of forms that have
been introduced in the construction of boilers and their appendages, with the
view of economising the production of steam. Those which we have already
given, however, afford a general outline of the whole, with the exception of
such as are employed in steam navigation. In these, it is fin essential condition
that the fire-place and flues should be entirely surrounded with water, so as to
E E
214 BOILERS.
prevent any contact of those parts with the wood-work of the vessel. We shall
give two examples of boilers of this description.
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The above engraving is descriptive of the boiler used in the United Kingdom
steam packet, of 1,000 tons burthen, measuring in her keel 148 feet, and breadth
of beam 14 feet, and propelled by two engines of 100 horses each, manu-
factured by Mr. Napier, of Glasgow. The boiler is of wrought iron plates,






































BOI LERS. 215
25 feet 6 inches long, 19 feet broad, and 8 feet 6 inches high. There are eight
rectangular tubes by running iengthways of the boiler; in each of these is a
fire at one end on the bars cºc, shown in section. At the farther end of the tubes
is a transverse one d, extending the whole breadth of the boiler, which commu-
nicates with every one of the tubes containing the fire; at each end of d on
the top, a return tube e e carries off the smoke and fire into another transverse
tube f out of the centre of which the chimney grises. The cocks h k h are for
ascertaining the height of the water in the boiler; but there is added a simple
contrivance, by which the necessity of employing the cocks h is avoided. There
are two cocks i i which are placed the one considerably above, and the other as
much below, the assumed level of the water; these cocks communicate with a
vertical tube of glass j of sufficient strength to withstand the force of the steam.
On the cocks i i being opened, water enters into the lower one, and steam into
the upper one, and the pressure being the same in the boiler, the water stands
at the same level in the glass tube, which indicates the height of the water in
the boiler.
In the subjoined engraving, which represents a patented, arrangement by
Mr. Steenstrup, a Swedish gentleman, in this country, the boiler is divided into
Fig. 1. Fig. 2.
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iftº
an upper and lower chamber, in connexion with the side chambers, and by
means of vertical tubes. Fig. 1 is an end elevation of the boiler; Fig. 2 *
transverse section; and Fig. 3 alongitudinal section, the same letters designating
similar parts in each. a is the upper division, or steam chamber; b the lower
chamber, connected with the upper by the side vessels, and by the vertical tubes
c c, as shown in the section; at d is the fire bars, on which the fuel is deposited;
e the fire bridge; f the ash pit; g part of the chimney, likewise surrounded
with water at the lower end, which is in contact with the vessel; h is the steam

*::::
216 BOLOGNIAN STONE.
pipe, and k the man-hole. It will be observed that the vertical tubes c c besides
forming a support to the weight of water in the upper chamber, and opening a
free communication with it, receive, from their position in the fire-place, the
strongest heat, and consequently give off steam quicker than the other parts of
the boiler, in particular those which pass through the fire bars, producing thereby
those ascending and descending currents, which are deemed so advantageous in
the generation of steam: also, from the great capacity of the fire chamber, that
fuel of any kind, however bulky, may be easily employed, by merely shifting
the fire bridge accordingly. In the description of the common waggon-shaped
boiler, in the early part of this article, the manner usually adopted of feeding
boilers with water was explained. The necessity of a due supply of the fluid
is so great, as to have induced numerous inventors to devise plans for insuring
its accomplishment. Several of the most approved arrangements for this purpose
are detailed in Galloway and Hebert's History of the Steam Engine; and we
shall close the present article by the description of another of great simplicity
and effectiveness, which was patented by Mr. W. Taylor of Wednesbury, since the
-º-º-º-º-º-º-º-º-º-º-º-º-º-º-º-º-º-, -, -, --
T*========= -------------------
------ ==E==========- --------- →------------ .
publication of the before-mentioned work. In the above figure, a shows a portion
of the boiler; b a water reservoir or feeding vessel, made steam tight; cºa pipe
through which b is supplied with water, having a valve d opening inwards. e is
a steam pipe, extending from the boiler to nearly the top of the close vessel b,
and c is a water pipe extending from the bottom of the close vessel to the
interior of the boiler. In both these pipes are stop cocks e and f, with levers
extending to g, by which they are opened and closed. In these levers are two
longitudinal slits, for the reception of a pin fixed in a rod extending from the
float h, through a stuffing box in the top of the boiler. Now when the water in
the boiler evaporates till its surface descends, and permits the weight of the
float to bring down the levers to the position represented, the cocks will be
opened, and the steam will rise through the pipe e, by which the pressure will
be equalized in the boiler a and the supply vessel b, and water will descend
through f till its surface in the boiler rises sufficiently high to raise the float and
shut the valves; and then the condensation of steam in b will cause a partial
vacuum, permitting a fresh dose of water to pass through c into the feed vessel.
BOLOGNIAN STONE. This stone is the ponderous spar, or native sul-
phate of barytes, the phosphoric property of which was first discovered by an
Italian shoemaker. If it be first heated to ignition, then finely powdered, and
made into a paste with mucilage, and this paste divided into pieces a quarter
9f an inch thick, and dried in a moderate heat, be exposed to the heat of a wind
furnace, by placing them loose in the midst of the charcoal, a pyrophorus

BOLTING MACHINE. 217
will be obtained, which, after a few minutes' exposure to the sun's rays, will
give iight enough in the dark to render the figures on the dial-plate of a watch
visible.
BOLTING MACHINE. . A part of the machinery of a flour mill, by
which the flour is separated from the meal, which operation is termed dressing
the flour. It usually consists of an hexagonal reel, over which is drawn a sack,
called the bolting cloth, of considerably larger diameter than the reel, and
composed of a peculiar species of duck made for the purpose. The reel is placed
in an inclined position, and made to revolve rapidly within six bars of wood,
called beaters, fixed to a case or box, within which the reel revolves. The
v & Yºº-
Fig. 8.
º
º:
º
º
º
º
º
:
º
*
reel being turned with great velocity, the centrifugal force would throw out the
bolting cloth to its utmost extent were it not intercepted by the beaters; the
repeated blows from these first force the flour through the interstices of the
cloth, and subsequently, at the tail end of the reel, the offal consisting of bran,
pollard, and sharps. The above engraving represents Ayton's improved
Flour Bolting Mills, constructed upon the principle just described, but provided
with the means of more easily and effectually regulating the tension and elas-

218 BONES.
ticity of the bolting cloth, so as to produce in it a uniform and powerful vibra-
tion, which is effected by secured loops at one end of the cloth to six elastic
steel arms or springs, instead of the stiff arms of the common construction.
Fig. 1 is a plan or front view of the steel arms a a, and Fig. 2 a side view
of the same in section. These arms are rivetted to a ring of metal c, and at
their outer extremities are formed into broad flat hooks to receive the loops of
the bolting cloth, for which purpose they are nicely rounded and smoothed.
The ring c is secured by two conical pointed screws to another ring d, placed
within c, sufficient space being left between the two rings to allow a small degree
of play. The ring d is in like manner secured to the central socket e by means
of two other conical pointed screws, with a similar allowance for play; the two
rings c and d forming a kind of universal joint. The socket e is put over the
square part of the spindle of the reel, and fixed at any part of its length by
means of a tightening screw. Fig. 3 represents the improved bolting machine,
with the front pannels of the case in which it is inclosed in order; the beaters
h h h h are fixed, the two which are in front of the machine being shown in
dotted lines; i is the revolving axis or spindle, to which is fixed a light hemi-
spherical frame m, over which the bolting cloth is drawn, and made fast to the
circular ring or curb n, by means of a string running in a band of leather
sewed to the head of the cloth to strengthen it; the loops to the “tail leather”
at the other end of the machine are fixed to the spring arms a a, already
described and shewn in their place upon the axis i, by which means the most
perfect and equal tension of the bolting cloth is obtained, and the beaters being
adjusted to a proper distance, the operation of bolting is very effectually per-
formed. Another improvement, although not claimed in the patent, is the sub-
stitution of four cloth fanners for the wooden rails, which compose the reel in
the ordinary machine. The fanners are constructed as follows: upon the spindle
i are fixed two “maces " or bosses k k, from each of which radiate four arms;
from each of the arms on the mace, a piece of duck, about six inches broad, is
stretched to the arms of the other mace as shewn at l l. When a rapid motion
is given to the reels, the pieces of duck l l set the air in brisk motion, by which
much of the flour is forced through the bolting cloth, the tension and tremulous
motion of which, by the elasticity of the springs, tend to prevent the clogging up
the interstices of the cloth, and the operation of bolting proceeds with great
regularity and expedition. Accompanying the description of the machine in
the patentee's circular, are several certificates from respectable millers of its
superior efficacy, which state that nearly double the quantity of meal is bolted
in a given time. There is another description of dressing machine, in which a
cylinder composed of wire gauze of various degrees of fineness is employed to
sift the meal instead of a bolting cloth.
BOMBASINE. A well known stuff, produced by various mixtures of cotton
and silk.
BONE ASH. The residue of burnt bones. The process is conducted in
the open air, in large heaps, and the earthy salt which remains forms on an
average about half the weight of the fresh bone. It is composed chiefly of
phosphate of lime, and is used by the assayers as the material for cupels, and
for other purposes.
BONES. The hard insensible substance of which the frame or skeleton of
animal bodies is formed. Although the proportion of the ingredients vary in
the bones of different animals, as also in different parts of the same animal, the
general constituents of bones are as follows: gelatin or jelly, soluble in hot
but not in cold water; fat, separable by boiling, when it rises to the top of the
water, and becomes concrete in cooling; phosphate of lime in large quantity; a
little sulphate and carbonate of lime; and a cartilaginous substance retaining
the form of the bone after every thing else has been extracted, by boiling and
by acids. The uses of bones in the arts are very numerous. Both in their
natural state and dyed, they are made into knife handles and various articles of
turnery ware. They are extensively used in the manufacture of ammonia, the
refuse forming bone black; or calcined to whiteness in the open air, they form
bone ash, which see. They are also employed in the preparation of milky
BONE MILL. 219
glasses and porcelains, for the rectification of volatile oils, and in the preparation
of glue; and recently in France, large quantities of gelatin have been extracted
from bones, which has been subsequently made into soups for hospitals, soldiers, and
restaurateurs. The process is as follows: the bones are first broken into small
pieces, and then thrown into a kettle of boiling water, and boiled for a quarter of
an hour. When this has become cold, a quantity of fat, amounting in some in-
stances to nearly a fourth of the weight of the bones, is found at the surface of the
liquor, and is applicable to many useful purposes. After this, the bones are ground,
and boiled in eight or ten times their weight of water, until about one half is wasted,
when a very nutritious jelly is obtained. M. Darcet recommends, instead of
grinding the bones, which is a work of great labour, to treat them with dilute
muriatic acid, which dissolves the salts of lime, leaving the gelatin untouched,
and retaining the form of the bones; this is afterwards to be repeatedly washed
in clear cold water to free it from all taste of the acid, and then if not required
for immediate use, to be thoroughly dried by long exposure to a gentle heat, after
which it is little affected by the atmosphere, and will keep for a great length of
time. It should be observed, that the bones should not be boiled in copper
vessels, as gelatin quickly attacks that metal. Bones are likewise extensively
used in agriculture as a manure, when reduced to a coarse powder; and large
quantities are collected for this purpose from various parts of the kingdom, as
well as from abroad, and sent to Yorkshire, where most of the bone mills are
established, to be ground. The annexed, Fig. 1, represents a side elevation
Fig. 2.
of a bone mill of an approved construction. . a a is one of the side frames, b
the driving shaft carrying a pinion c, which turns the wheels d to the axis e,
and the wheel f upon the axis g; h i are a pair of fluted rollers fixed to their
respective shafts e and k, and turning in contrary directions by the action of
the two wheels l and m, also affixed to the same shafts; n and o are another


220 BOOK BINDING.
pair of rollers affixed to the shafts q and p respectively, and likewise turned in
contrary directions by a pair of wheels upon the same axes. These rollers are
composed of a series of wrought iron discs, with teeth resembling those of a
ratchet-wheel, and fixed up the shaft, with a plain disc of smaller diameter
interposed between each pair of the toothed disc, as shewn in Fig. 2, and so
arranged that the toothed discs on one shaft shall face the plain discs on the
other. The most valuable part of the bones is first removed by a circular saw,
and set apart for the uses of turners and others; the joints and refuse are then
put into the hopper q, and descending upon the rollers hi, are crushed, and fall
into the hopper r, whence they pass between the rollers l m, where they are
reduced to a coarse powder, which is conducted by the shute s (in dotted lines)
to the receiver. To prevent the teeth of the rollers being broken by any
excessive resistance, the plummer blocks, which support the shafts k and p, are
not fixed to the side frame, but are retained in their places by pins passing
through chase mortises in the frames, allowing the blocks to slide along the
frame, and the rollers are kept in contact by means of weighted levers w a,
pressing upon short studs y 2, attached to the plummer blocks, which carry the
shafts k p. - -
BOOKBINDING is the art of securing together a number of separate leaves
into one book, and is of very great antiquity, the invention being generally
attributed to one of the kings of Pergamus, to whom we are also said to be
indebted for the invention of parchment. Bookbinding, properly so called,
includes the binding of all printed books; while vellum-binding is the term
applied to the binding of every description of account books. The two branches
are quite distinct, and seldom, if ever, successfully practised by the same in-
dividual; we shall therefore describe each branch separately, beginning with
bookbinding. Although the limits of this work preclude the possibility of
entering minutely into all the practical details of the subject, yet it is hoped
that the following account will be found to contain a clear and connected view
of the nature of each process, and of the tools employed, with a brief notice of
some of the more striking attempts at improvement.
In binding printed books, they are generally received by the binder in sheets,
which are folded into quartos, octavos, duodecimos, &c., as the case may be.
This process is assisted by certain catch-marks or signatures, printed at the
bottom of each sheet, by attending to which, and keeping the folio of one page
on the folio of another, and at the same time preserving the necessary corre-
spondence between the foot of each page, the work will be properly folded, and
an uniformity of margin preserved throughout the work. The book having been
folded and pressed, is next beaten on a large smooth stone, with a cast iron
bell-shaped hammer, weighing from twelve to fourteen pounds. This beating
requires great care and skilfulness on the part of the workman, and various
attempts have been made, at different periods, to supersede the process, by the
use of hydraulic and other powerful presses; these, however, have proved unfit
for the purpose, generally creasing and disfiguring the work. Mr. Burn, of
Hatton Garden, has, however, succeeded in rendering books extremely compact
and solid, by passing the sheets, when folded, between a pair of powerful
rollers; and this method will eventually supersede the old laborious and imperfect
one of hammer-beating. The apparatus of Mr. Burn consists of two iron
cylinders, about 12 inches in diameter, adjustable in the usual manner by
screws, and worked by manual labour applied to one or two cranked handles.
A boy sits in front of the press, who gathers the sheets into packets by placing
two or more upon a piece of tin plate of the same size, and covering them with
another piece, and thus proceeding, by alternating tin plates and bundles of
sheets, till a sufficient quantity have been put together, which will depend
greatly on the thickness and hardness of the paper, &c. The packet so formed
is then passed between the rollers, and is received by the man who turns the
winch, and who has time to lay the sheets on one side, and hand over the tin
plates, by the time that the boy has prepared a second packet. The time
occupied in this process is about one-twentieth of that requisite for beating. It
is not merely a saving of time, however, that is gained by using the rolling-

BOOKBINDING. 221
press, for the paper is rendered much smoother, and the compression of the
book is one-sixth greater than could have been obtained by beating. The
Society of Arts presented Mr. Burn with their silver Vulcan medal for his
invention, which is now in very general and extensive use. Newly-printed
works will not admit of beating or rolling, and books which are only to be
boarded, do not require more than a good pressing. After beating or rolling,
the book is collated, and the plates (if any) put in their respective places. It
is then put in the standing press, and after remaining there a short time, is taken
out, and the waste leaves added at the beginning and end. The book is then
taken up between the extended fingers of each hand, and the back and head
knocked up nice and square; one side of the book is then laid upon a pressing
board as large as the book itself, beyond which the back must project about half
an inch; a second pressing-board, corresponding in size and position with the
former, is placed upon the upper side, and the board being firmly grasped with
the left hand, the book is lowered into the cutting-press, which is screwed up
tight, and a certain number of grooves, according to the size of the book, are
cut in the back with a tenon saw, for the reception of the cords on which the
book is to be sewed. After sawing, the sections are parted by passing a folding
stick up and down between them. The book is then taken to the sewing-press,
of which the accompanying is a representation. It consists of a stout flat
s
Tº 2S.sŠsº§Š-Nº.º,*
board a a, and two upright screws b b, with a long opening between them. A
top rail crises and falls upon the screws by means of two nuts d d. Several
cords, suited in size and number to the kind of books which are to be sewn, are
attached to the rail c, and set to correspond with the sawed grooves in the
back of the book; the cords being carried down through the aperture in the
bed of the press, are fastened underneath by means of brass keys, of which e
is a representation. The number and distances of the bands are quite arbitrary,
and are disposed according to the fancy of the workman; it may, however, in
general, be regulated as follows: 32mos. three bands; 18mos., 12mos., 8vos.,
and two-leaf 4tos. four bands; royal 8vos. and whole-sheet 4tos. five bands;
and folios from five to seven bands. In sawing the back two extra grooves are
made, one at each end of the book, for the catch or kettle-stitch. The book
being placed with the back towards the sewer, and the title uppermost, the fly-
leaf or end paper is first laid upon the press and sewed to the cords, by passing
the needle in the first right-hand groove or catch-stitch mark, with the right
hand; the left hand being kept in the middle of the section, receives the needle
F F









222 BOOKBINDING.
and draws it through, leaving two or three inches of the thread undrawn. The
needle is then returned out on the head side of the band, received by the right
hand, and passed through on the other side of the band, by which the thread is
conducted round each band in succession. The needle being carried along the
in side of the section, and led round each band in this manner, is at last brought
out of the last groove or left hand catch-stitch mark. The first section of the
book is then taken and sewed to the bands in the same way; when the needle
comes out at the catch-stitch mark, over the end of the thread left out of the
fly-leaf in the first sewing, the thread is tied to it in a knot. The remaining
sections are then sewn, the thread being fastened through the catch-stitch of
each preceding section. Care must be taken not to draw the thread of the
catch-stitches too tight, but to keep the back equally swelled. A number of
books may be sewed one on another, till the press is three parts full, care being
taken to finish off the sewing of each book, and not to catch-stitch them together.
The proper number of books being sewed, the strings are cut from the rail, and
unfastened at the bottom; the books are then separated and the bands cut apart,
leaving about two inches on each side of the book. After sewing, the back of
the book is glued; and when that is dry, the ends of the bands are opened and
scraped. If the book is to be lined, which is customary with all half-extra and
other superior work, it is now done, either with fine coloured or marble paper.
If with marble paper, the sheet is folded with the plain side outwards, one half
of it being pasted; it is laid between the fly-leaves, into the fold of which it is
closely worked; the other half is then pasted, and the next fly-leaf rubbed
down upon it, any superfluous edges being cut off with the shears. This done,
the back is next to be rounded, which is effected by laying the book on the
press cheek, with the fore-edge towards the workman, who presses the fingers
of his left hand upon the book, and at the same time draws it towards him,
gently tapping the back up and down with a hammer, alternately changing the
sides until the book is uniformly and effectually rounded. The back is then
squeezed in the cutting press for a few minutes, which sets it, and the book is
then ready for backing. This consists in forming a projection of the back on
each side of the book, sufficient to cover the boards, and is done by placing
cutting boards on each side of the book, within about a quarter of an inch of
the back, or according to the size of the book, care being taken that the boards
are parallel with the back, and at equal distances from it. The boards being
tightly grasped by the left hand, are lowered into the cutting-press and screwed
tight; the back is then hammered gently and uniformly all over, which causes
it to spread over the boards so as to form the required ledge or projection. If
any roughness appears on the back, it is removed by scraping, and cleaned off
with paste and paper shavings. The boards for the cover, which are brown
milled boards, having been cut to the required size with shears, or ploughed in
the cutting press, two holes are pricked with a bodkin for each band, one of
them directly opposite the band, the other about an inch beyond it. The first,
for 8vos., should be about half an inch from the edge of the board, the others
about an inch, or for larger works still forwarded. The bands are then drawn
through the outer side of the board, and passed through the other hole to the
outside again, where the ends are spread and pasted. Each board is then opened,
and laid separately on a smooth piece of iron, and the strings hammered flat.
The boards, which should not be put on too tightly, having been properly
adjusted, and the back examined to see that it has not been deranged, and the
defects, if any, remedied with the backing hammer, the next step is cutting
the fore-edge. For this purpose the boards are thrown out of the grooves or
ledges, and then brought to a perfect level with the back by knocking on the
cheeks of the press; a cutting-board (of oak or beech, and rather wedge-shaped)
is then placed on the left hand side of the book, and another, called a runner,
on the right; the whole is then placed in the cutting-press, the runner being
brought even with the right cheek of the press, and when properly adjusted,
the press is screwed up, and the fore-edge ploughed. After cutting the fore-
edge, the book is taken out, and the back rounded as before, when a corresponding
groove will be formed in the front. The head is next cut by knocking the
BOOKBINDING, 223
boards straight up with it, keeping them in the ledge produced by backing;
the cutting-board and runner are then applied as before, and the head ploughed.
For cutting the opposite ..? …"
end, the boards are slipped 2^
below the head as much
again as it is intended they ..f
shall project, which should i
ſº
a . º §
be rather less than on the
fore-edge. A small piece
is then taken off the inner
corner of each board; and
the boards being replaced,
there will be found a suffi-
cient projection for both
ends.
The cutting-press which
has been referred to, con- 1. **
sists of two strong wooden cheeks f g, connected by two slide bars h h, and
two wooden screws i i. Upon the cheek f are two guides for the plough to
work in.
The plough, which is the cutting -
instrument, consists of two sides, k l,
connected by a screw m, and two slide
bars, n n. A knife o is fastened to the
under side of the cheek l, by a strong
square bolt, which takes into a groove
cut on the circumference of the screw
m, and prevents it from moving later- º
ally in the eheek. When the screw }
is turned, therefore, the two sides of
the plough approach to or recede from
each other.
Various attempts have at different
times been made to improve the cutting-
press and its appurtenances. Mr.
Baxter, of Lewes, proposed to obviate
most of the inconveniences attending
the use of the common plough-knife.
His improved knife consisted of a brass
or gun-metal stock p, having a dove-
tailed groove on its under surface, in
which slides a steel blade or cutter r,
which is kept in any required position I
by a set screw on the upper part of the stock at s. The great advantage
of this knife is, that when once properly adjusted, the blade may be changed
and ground ad infinitum, without deranging the adjustment of the stock.
In the year 1806, the Society of Arts presented Mr. J. Hardie, of Glasgow,
with a reward for an improved cutting-press for bookbinders, which is delineated
in the cut at the top of page 224. t is the left hand cheek of the press, con-
nected with a frame v v v, having two grooves on the inside, in which the cheek
w slides backward and forward by means of the iron screw ar, which is secured
to it by a collar at y, z are the guides for the plough. The advantages
claimed for this press are its simplicity, great power, and increased facility of
use, as compared with other presses.
But the most striking improvement is in a cutting-press recently constructed
by an ingenious mechanic named Penny, which promises to be of great practi.
cal utility; for with this press, an indifferent workman will cut the edges of
books or paper with mathematical accuracy and precision, which the very best
cutter with the old press could never accomplish. Penn'ys press consists of
two cheeks, with screws and slide bars, as in the ordinary machine; but to the
º
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º
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tºº
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º
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224 BOOKBIND ING.
º
£:
gº
ſº
. . . º
|
tº: : i #
ſº t # | #.
ſh º ſ gº
tº ſº
ū ºr "
ū. | |W
§: º
| |
ill
| º:
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º -
il
§h
under side of the left hand cheek, a framing A A is attached, which projects
some distance under the other cheek. Within this frame, a platform B rises and
falls, perfectly parallel with the - - -
upper surface of the press, by
means of a rack to which the
platform is attached. A pinion
at C, gives motion to the rack.
On the axis of the pinion, and
on the left hand side of the
press, there is a large wheel D
which the workman turns with
his hand, to give the platform
the necessary elevation, fixing
it in any position, by means of
a small catch. As the platform
moves perfectly parallel with
the surface of the press, and at
right angles to the frame A A,
it follows that any thing resting on the platform will be cut true throughout its
whole thickness. This has been shewn to be the case, by taking off consecu-
tively, shavings from paper the thirty-second of an inch wide, which were per-
fectly accurate throughout, from first to last. The surprising accuracy of this
press, however, would be of little avail with ploughs and knives of the usual
description. Mr. Penny has therefore so far improved the plough as to make it
a fit accompaniment to his press. For this purpose, the sides, screw, and slide-
bars are made with considerable care, the under surface of the sides being shod
with metal, which on the
right hand side is formed
into an appropriate bed for
the knife, as at E. The
knife is of the form shewn
at F; the blade is placed ;
directly under the screw,
and secured by two screw
bolts, in lieu of one. The
bed for the knife being
metal, and the knife itself
being accurately finished,
no tedious adjustment is
ever necessary. The knife
being in the centre, stands























































BOOKBIND IN G. 225
to its work well, and the plough does not twist about like the old ones. Mr. Penny
received a reward from the Society of Arts, in 1832, for his improved piough.
The standing-press employed by bookbinders is usually the common screw-press,
worked by a long lever, to which the power of a windlass is sometimes added.
Having thus briefly noticed some of the machinery which is employed by the
bookbinder, we return to the book, the edges of which had just been cut; the
next thing, therefore, is to ornament its edges, which is done either by colouring,
sprinkling, marbling, or gilding. The first of these processes is the most
simple, and is that usually adopted for the commonest work. The books being
laid one on the other, or screwed in the cutting-press, the colour is applied with
a sponge. . The colours, mostly employed for this purpose, are Spirit-blue,
Brown-umber, King's-yellow, Dutch-pink, Spanish-brown, and Vermilion, mixed
with size, Sprinkling is performed by dipping a stiff brush in the colour, and
striking it upon the press-pin held in the left hand, by which means the colour
is thrown upon the books in fine spots, and a little practice enables the workman
to distribute them very equally all over the edges. Better kinds of books, however,
are generally marbled on the edges, the patterns being made to correspond with
the marble paper lining. Marbling is performed as follows: a trough is pro-
vided of a convenient size, about two inches deep, which is filled with clean gum-
water; various coloured pigments, ground in spirits of wine, and mixed with a
small quantity of ox-gall, are then thrown upon the snrface of the gum-water, and
disposed in various forms, according to the pattern that is desired, with a quill
and comb. The proper pattern being obtained, the book is tied between two
boards, and the edges dipped into the trough, when the floating colours become
transferred to the book; cold water is immediately dashed over the edges,
which sets the colours, and gives them a clear appearance. If the edges are to
be gilt, they are nicely cut and tied between two boards; they are then sponged
over with yellow-ochre, which is scraped off, and the edges rubbed dry with
paper shavings. Parchment size, or a size composed of equal parts of water
and white of eggs, is laid upon the book edge, and covered with gold leaf; it
is then dried gradually, and before it gets quite hard, is burnished with an agate
burnisher. The edges are then protected from injury during the remainder of
the process by a paper covering. Head-banding then follows. Head-bands are
of two kinds, stuck on and worked. The stuck-on head-band is formed by
cutting a piece of striped or coloured linen about an inch deep, and equal in
length to the thickness of the book; one side is pasted, and a piece of well-twisted
cord laid across one third of its width; it is then folded over, enclosing the
string, and worked well up to it. The back of the book being glued, the
linen is laid upon it, the cord or head-band being placed flat upon the end of
the leaves. For all extra work, however, the head-bands are worked in the
following manner. A strip of thick vellum, board, or string, prepared by rolling
it tight in pasted paper, is taken of a dimension suited to the size of the book;
stout well-twisted silk, of two or more colours, is then taken; if two colours are
used, they are doubled and tied together by the ends, one of them being previously
equipped with a needle. The book is then placed in the cutting-press with the
back uppermost, the head towards the workman, and considerably elevated; the
needle is then passed through the middle of the second section, on the left-hand
side, just below the catch-stitch, and drawn out far enough to bring the knot
joining the two silks close into the middle of the section; the needle is then brought
up, and passed again through the same place, and the silk drawn nearly close;
the round strip is placed in the loop thus formed, and the silk drawn tight
with the left hand; the other silk is brought over with the right, and passed
under and over the head-band, when that is held tight with the left hand; the
other silk is now put over that, and also under and over the head-band; they
are thus worked alternately over each other, as far as the middle section of
the book, through which the needle is passed below the catch-stitch, and
brought over the head-band, when the working is proceeded with as before, as
far as the last section but one; the needle is passed through this section, and
over the head-band twice, and finally fastened on the back. The ends of the
head-band are then cut off, almost close to the silk at each end. The part
226 BOOKBINDING.
produced by working one silk over the other is called the braiding, which forms
the principal beauty of the head-band, and should be ranged close down upon
the *. of the book on the inside of the band, which is easily managed.
Both ends of the book having been worked in this way, the glue brush is
drawn across the back of the bands, which strengthens them and keeps them
in their proper places. It is now the usual practice to make a hollow back, on
account of its enabling the book to open better, and also preserving the leather
from cracking. The hollow back is formed by cutting a strip of cartridge
paper twice the width of the back, and the same length; this is folded in half,
and the back being fresh glued, one half of the folded paper is stuck on, the
other half being doubled upon it. If the book is to have raised bands, they
are now put on ; they are formed of strips of thick leather, as wide, and at
such distances from each other, as taste directs; they are glued on the loose
back, and pared down at the ends, the sides being kept sharp and square.
They are used to give a neat appearance to the back, and are a great improve-
ment on the old method of sewing the book on raised bands in lieu of the
sunken cords. The book is then ready for covering, with leather, if to be
whole bound, or with leather and paper, if to be only half-bound. For whole
binding the leather is cut about half an inch larger all round than the book,
and carefully pared round the edge with a sharp knife on a piece of smooth
marble; it is then pasted, folded together, and left a few minutes for the paste
to soak in; it is then opened out, and the book laid on one half (the fore-edge
being towards the workman), while the other half is carefully and tightly drawn
over the back and uppermost cover; the covers being then adjusted at the
head and foot, and pulled forward, the edges are turned down and the ends
tucked in; the corners being raised are worked together, and the part so raised
cut off, and the head and foot pieces being smoothed down, the fore-edge part
is folded over them. The head of the book is then neatly set with the folding-
stick, pressing it inwards in the joint where the corner was taken off the boards,
and flatting the leather over the top of the head-bands; the form thus given in
the damp state is permanently retained when dry. If the raised bands, previously
described, are used, a piece of fine cord is tied round the book, (the edges being
guarded with a piece of board), pressing on the upper and lower side of each
band, which brings the cover close upon the back, and preserves the distinctness
of the bands. For half-bound books a strip of leather is cut, about an
inch longer than the back of the book, and of sufficient width to lay well over
the boards; the leather corner pieces are cut of an oblong quadrangular shape.
The leather being pared, the corner pieces are put on first, and the back
afterwards, being worked in the same manner, and with the same care, as the
whole-bound book. Marble, coloured, or other fancy paper, is cut of a proper
size and form, and pasted on the sides. Smooth sheep and calf bindings are
frequently ornamented by marbling or sprinkling, which is performed by throwing
various colouring liquids on the cover while it is wet with water : but there is
so great a variety in these processes, both of colours and patterns, that there is
not space for their enumeration here; nor are they of much importance at this
time, the coloured leathers having been brought to such perfection, and in so
general use, as to render the employment of sprinkling, &c. of more rare
occurrence than formerly. The forwarding of the book is now completed, and
it is handed over to the finisher. The first step of the finisher is to wash the
cover of the book with paste or glue water, to prevent the glaire from sinking
in and staining the cover; when the sizing is dry the cover is glaired. Morocco
and roan require to be glaired but once, sheep twice, and calf three times; this
done, the book is ready for gilding and lettering. The places where the gilding
is to be applied, are then slightly greased with palm or sweet oil, and covered
with gold leaf. While lettering and gilding the back, the book is placed in the
cutting-press, with the head a little elevated. The brass letters having been selected
and laid in their proper order before a fire, are moderately heated; before using,
they are tried on a piece of waste leather; when at the proper temperature,
they are forcibly impressed upon the gold, one after the other, care being taken to
keep them straight, upright, and at uniform distances—a process which requires
BOOKBINDING. 227
great practical skill. The whole of the letters being worked, the superfluous
gold is wiped off with an oiled rag, to which it adheres, and when saturated,
the rag is sold to the refiner, who recovers the gold which it contains. Common
words of frequent use, such as Bible, Prayer, Album, &c. &c. are cut in one
piece, and worked off at once, which greatly facilitates the process of lettering,
while it insures a uniformity of appearance not otherwise attainable. Metal
types are sometimes used as an excellent substitute for the brass letters; with
the former, any word may be set up in a frame and worked at once, but it is
essentially necessary that the types are clean and bright; there is also some
difficulty in giving them the proper temperature; it would therefore be a great
improvement to have brass letters cut so that they might be set up in a frame,
in the same manner as the types. These would combine the beauty and accuracy
of the brass letter, with the convenience of the types. The lettering having
been completed, the remainder of the book is gilt with appropriate tools; these
in general consist of straight lines or fillets, rolls of various breadths and patterns,
and single ornamental devices, all cut in brass, and used the same way as the
letters. The tools are frequently heated, and worked upon the leather without
the interposition of any gold, which produces a neat and elegant contrast to the
gilding; it is denominated blind-tooling. Whole bound books are frequently
very handsomely gilt on the sides as well as the back, frequently by running a
broad gold roll round the edges of the cover, and sometimes by means of corner
and centre pieces, with or without lines. The following ingenious method of
working these ornaments was designed by Mr. Bain, of Broad-court, Long-acre,
who received the silver Isis medal and five pounds, from the Society of Arts,
for his invention. The brass ornaments used for the covers are mostly triangular
ones for the corners, the centre being formed by the combination of the same
or other four pieces. In the ordinary manner of working, a single tool is used,
which requires to be applied eight times on each cover, or sixteen times in all
on each book. This occasions the loss of much time; to save the greater part
of which, Mr. Bain employs four triangular blocks, capable of being fixed in a
simple adjustable frame, so as to suit any sized book. The frame a a in the
a CCOIn O3. In VII 19 eI) QTaº- E): º:
ving, .. . to i. Fig. 2. Fig 1.
the rods b b parallel to
6. € . . . % e *
each other, and allow |
them to be set at an Nº. Vº w- - -
required distance * =- § § Ä ‘. d
c c c c are the stamps, § § º
which are perforated % } {
to slide on the rods b b - - - Aft jº aſ
quite even with each º "T Hé i lm
other; they . fixed éº -
at the proper distances Wºź
OI). .P . by small ſ Fº sº f ſh
set screws at their back, % y
which bind upon the & ſ |
rods. The frame a a HRH TH ſº ſº ſ
has two long apertures, - T º §d j= ºf 5 s
seen in Fig. 2, to receive Zºffº £ft *...
the rods b b, which have U. C C ºr flaſ
square shoulders and * ||a AE A
fins to traverse along,
and are bound fast by the screwed nuts. d d shows one of the rods, with its nut
separate. The small nuts e screw on after the stamps, to keep them from falling
off the rods before they are adjusted. It will be seen that by sliding the stamps
c along the rods b, and these rods along the frame a, they may be adjusted to
suit any size and form of book. When the corners are done, if the same stamps
are to be used for the centre, they may be transposed on the rods, and adjusted
to suit the centre, as shown at ff; but it will save time, and do the work truer,
to have four rods b b and ff to hold the corners and centre stamps at the same

228 BOOKBINDING.
time, for then once putting in the press does one side of the book, and all will
be exactly alike, without much care on the part of the workman. If the frame
a a is made a little wider than the thickness of the stamp on the pattern side,
it might be adjusted to touch the fore-edge of the book, which would keep the
pattern quite straight and equidistant on each book. By this contrivance, not
only is time saved, but the patterns are registered much more accurately than
they could possibly be by any other method. When very large lettering pieces,
ornaments, or coats of arms, &c. are to be gilt upon the covers of books, manual
pressure is inadequate to the working of them, and a press is employed, called
an arming press. A very perfect machine of this description has recently been
constructed by Messrs. Cope and Sherwin, of London, to which they have given
the name of the “Imperial Arming and Embossing Press,” which is not only
capable of working every description of gilding, but is also sufficiently powerful
to emboss the elegant arabesque covers, at present so much employed for
ornamental bookbinding. The largest description of these covers are embossed
by means of a fly-press of enormous power, but for all smaller work the imperial
press is amply sufficient. In its construction it resembles the improved printing
press invented by the same parties, but with the addition of a contrivance for
raising or lowering the bed to suit the thickness of the book, and the platten
likewise having receptacles for the heating irons. By means of a screw-and-
wedge adjustment in the piston, and the rising and falling bed-plate, a considerable
range, with the power of very accurate adjustment, is obtained with great facility.
This machine is exceedingly simple in principle and construction, elegant in
appearance, and effective in operation, and is a valuable auxiliary to the book-
binder. The book having been gilded, it is polished with a hot iron, and the
edges, if coloured or marbled, are burnished with an agate burnisher: the book
is then finished. If the book was only intended to be put in boards, or, as it is
technically called, boarded, it is folded, sewed, glued, the covers cut to the size
and put on, and then covered with coloured paper, the edges of the book
remaining uncut. Eactra boarding has stouter boards than the former, and is
finished with rather more care; sometimes the edges are cut, and the book
covered with a neat coloured and embossed or printed cloth, which gives a very
meat appearance at a cheap rate.
WELLUM BINDING, as was before observed, is the term applied to the binding
of every species of account book. The first step is to fold and count the paper
into sections, which in foolscap generally consists of six sheets; above that
size, of four sheets, which are sewed upon strips of vellum. Small books, up
to foolscap folio, usually have three strips; above that size the number is
increased. Account books are sewed much in the same way as printed books,
except that vellum slips are used in lieu of the cords, and a much stronger thread
and wax are employed. After sewing, the first ruled leaf at each end is
pasted to the waste paper, and the marble paper lining introduced; the back is
then glued in the usual manner. When the glue is dry, the fore-edge of the
book is cut, and the back rounded, a deeper hollow and rounder back being
formed in account books than in printed ones. The two ends are then cut, and
the edges marbled. The head-bands are worked on a slip of stout board, as
before described, care being taken in this instance to form a deep narrow, rather
than a round band. Strong pieces of canvass or buckram are then glued at the
top and bottom of the back, and between each of the vellum slips. A hollow
back is prepared by taking a slip of milled board, about a quarter of an inch
wider than the back of the book, and soaking it in water; it is then glued on
both sides, and left in this state for about ten minutes: having been laid on a
sheet of paper, a roller corresponding in dimension with the back of the book
is placed upon it, and the whole worked backward and forward on the roller,
which gives the milled board a semicircular shape; it is then dried hard before
the fire. Another method, which is a very good one, and frequently adopted,
consists in taking a roller (an assortment of the most useful sizes being kept for
the purpose), and winding round it thick paper and wrappers well pasted, until
the requisite thickness is obtained ; the roll is then thoroughly dried and
divided longitudinally, which forms two good firm semicircular backs. Milled
BORING BIT. 229
boards of a thickness proportionate to the size of the book are then taken, and
the fly-leaf of the beek being pasted, the board is laid on in its proper place;
the same course is also pursued with the other side. It is customary with
large books to use two thin boards pasted together, instead of one thick one :
in this case the vellum slips on which the book is sewn, are inserted between
them, which adds greatly to the strength of the binding. After the boards have
been squared, the back, formed in the manner described above, exactly fitting
the back of the book, is placed upon it, and a piece of canvass being cut suffi-
ciently large to extend half the width of the back on one side of the book to
the same distance on the other side, is glued on the boards and over the back,
which contributes to strengthen the book, and hold the hollow back firmly in its
place. The back is sometimes formed of sheet iron, which, in large books, is
an improvement: this kind of back was first introduced by Mr. John Williams,
who took out a patent for his invention. The book is now ready for covering:
the leather for the cover is carefully pared all round, and put on as before
described under the head of Bookbinding. The covers mostly used by vellum-
binders are forril and vellum, white and coloured; smooth and rough calf and
sheep; basil, smooth and grained, and Russia; in any of which books may be
either whole or half-bound. Forril and vellum covers are lined with paper and
pressed smooth; when dry, they are fitted on the back, and creased in the
joints; the boards are then pasted, and the covers pressed on them; when dry,
the edges of the cover are pasted and turned in, and the book again pressed;
the cover is then washed with a sponge and paste-water, and then ruled off. If
the cover is rough calf or sheep, it is dressed with pumice-stone and a clothes
brush. Smooth calf, basil, &c. are glaired and polished as described in book-
binding. Rough calf books are usually ornamented by passing a roller round
the edges and sides of the cover, with sometimes an ornament added; for this
purpose, the tools must be used nearly red hot. To increase the strength of
large books, they sometimes have, in addition to the leather or vellum cover,
bands of Russia leather, which ar worked on with thongs of vellum, and give
the book a very meat appearance. The lettering of account books is precisely
the same as before described.
BORACIC ACID. An acid which, combined with soda, forms borax, or
borate of soda. As obtained by the action of sulphuric acid upon a solution of
borax, it is in the form of thin irregular hexagonal scales, of a silvery whiteness,
having some resemblance to spermaceti, and the same greasy feel. By fusion,
it is converted into a hard transparent glass, which is used in the composition
of false gems.
BORAX. A compound of soda and boracic acid, and of considerable use
in various metallurgic operations. It enters into the composition of reducing
fluxes, and is of the greatest use in analysis by the blow-pipe. It is more
especially used in soldering; it assists the fusion of the solder, causes it to flow,
and keeps the surface of the metal in a soft clean state, which facilitates the
operation. It may also be applied with advantage in glass manufactories; for
when the fusion turns out bad, a small quantity of borax re-establishes it.
BORING BIT. A tool or instrument used for making aper ures in wood,
metal, or other hard substances. They are of various shapes, too common to
Fig. 1. a-E.---- ". . . . . . . . . .” &
workmen to need description; but one of a very *. and effective kind,
represented above, was brought from Germany by Mr. Donkin, and is described
in the Transactions of the Society of Arts. Pig. 1 is a front view of the boring
G G



230 BORING MACHINES.
bit; a a the cutting edge; b b a thread or fin, winding round the back, which
acts as a screw to draw the bit into the wood. Fig.2 is a side view of the same.
The instrument is very simple, enters the wood rapidly, and forms a clean hole.
BORING MACHINES. A name usually confined to machines for giving
a perfect form to metallic cylinders, as pump barrels, blowing machines, &c.,
which machines differ from lathes in the circumstance of the tool revolving,
whilst the work either remains stationary, or advances in a right line. In all
boring machines, a long bar, called the boring bar, passes through the cylinder,
and revolves in bearing or supports. To the boring bar are fixed a number of
steel cutters, which, as they revolve, receive also a motion endways, and are
carried through the whole length of the cylinder to be bored. The boring
machine used for the smaller and coarser description of pump work is extremely
simple in its construction. It consists of a boring bar, somewhat more than
double the length it will ever be required to bore, and supported by bearings
distant from each other not quite half its length. A mortise is cut through the
boring bar, and the cutters are firmly fixed in it by wedges or keys. Into a
socket in one end of the bar is keyed a screw about half as long as the bar,
and its outer extremity supported in a nut fixed in a standard, the axis of the
screw and of the bar exactly coinciding or forming a continuous right line.
The bar being passed through the cylinder to be bored, and the cylinder being
secured upon beds so as to be concentric with the bar, the latter is turned round
either by a winch or a wheel, fitted upon the end opposite the screw; and the
screw making a revolution in its nut for each revolution of the bar, advances
the bar and cutters through a corresponding space along the cylinder. For
cylinders of larger diameter, and requiring more accuracy in the boring, a
different construction becomes necessary. The cutters are fixed upon the cir-
cumference of a short cylinder, termed the cutter-block, through which the
boring bar passes; and either the two, as they revolve together, receive a slow
end motion, or the cutter block only advances whilst the bar revolves, but remains
stationary. There are various modes of advancing the cutters in either case.
The following extremely ingenious arrangement, in which the boring bar and
cutter advances, carrying with it the cutter block, is, we believe, the invention
of Mr. Murray, of Leeds. Upon the extremities of a horizontal bed of cast
iron are fixed two upright standards, supporting brass bearings, in which the
boring bar turns. Upon the cast iron bed are two blocks, for supporting the
ends of the cylinder, with arrangements for adjusting it, so that its centre shall
coincide with the axis of the boring bar, and to these blocks the cylinder is
firmly secured by straps or chains. The boring bar is turned perfectly cylin-
drical, and has a groove extending from one end more than half its length.
The cutter block, which is a disk nearly of the same diameter as the cylinder,
and armed at the circumference with a number of steel cutters, is firmly keyed
upon the bar in the space lying between the standard. Upon the grooved end
of the bar, and close to the outer face of the standard, is the driving wheel, the
centre of which is bored of the same diameter as the bar, so as to allow the
latter to slide within it freely, but without shaking, whilst the wheel is prevented
from turning without causing the bar to revolve, by means of a steel key, fitting
into the groove in the bar, and into a similar groove in the boss of the wheel.
A screw, half as long as the bar, is supported at the outer end by a nut, which
is at liberty to turn in bearings placed upon a vertical standard, whilst the inner
end of the screw, formed into a square, is keyed into the end of the boring bar.
Parallel to the screw is a small shaft, having at one end firmly fixed a small
wheel geering into another small wheel fixed upon the face of the nut, whilst
another wheel, which turns with the shaft, but is at liberty to slide along it,
geers into a wheel fixed upon that end of the bar to which the screw is attached.
The operation of the machine is as follows: The driving wheel turns the
boring bar, and with it the screw. Now if the nut were to remain at rest, the
screw would advance through a space equal to the rake of the screw, and draw
after it the boring bar; but if the nut, by properly proportioning the diameters
of the small wheels, revolve in the same direction as the cutter bar, but with a
less velocity, then the cutter bar and screw will advance through a space
BORING MACHINES. 231
proportioned to the difference between the velocities; so that if the speed of the
cutter bar exceed that of the nut by one-tenth, the screw and cutter bar will
advance through only one-tenth of the rake of the screw. In the boring
machines for cylinders of very large dimensions, the cutter block, usually
advances, whilst the boring bar remains stationary. In these machines the
boring bar is sometimes placed horizontally, but we think a vertical position
preferable, as the weight of a long horizontal bar occasions a tendency to sink
in the middle; also when the bar is vertical the cylinder is more easily fixed,
and the borings, instead of clogging the cutters, fall upon the base plate. The
annexed engraving represents a vertical boring machine of a new and improved
construction, which was erected in an extensive engineering establishment, and
of which we believe no description has yet appeared in print. Upon a foundation
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plate a are bolted three standards, of which only two b c are shown, the third
being removed to show the boring bar. These standards support the top plate
d, formed of three radiating arms; e is a steadying bridge, which may be set at
any height, by means of screws passing through the mortises in the standards,
and secured at the back by nuts; f is the bed to which the work is bolted, for
which purpose it has a number of mortises radiating from the centre; it is
supported by brackets g g projecting from the standard; h is the boring, turning
in collars in the top plate d and in the bridge e, and supported by the step i ;
A the cutter-block, which is a stiff wheel, bored out accurately to receive the
boring bar, so as to slide upon it easily, yet without any shake. On the
periphery of the block are eight notches, in which the cutters are fixed by
wedges; l a bevelled wheel, and m a pinion by which a rotatory motion is
given to the boring bar and cutter block, the latter being made to advance along
the former by the following means: Upon the top plate d is a small triangular


















































232 BORING MACHINES.
frame n, to which is bolted the bevelled wheel o, in which another wheel p
geers. , p revolves in bearings fixed upon the head of the boring bar, and has
upon its axis an endless screw driving the worm-wheel q, which is fixed
upon a long screw r, lying in a mortise cut in one side of the boring bar.
This screw turns in collars s and t, and works in a nut fitting into the mortise
in the boring bar, and attached to the cutter block at v; the bevelled wheel
p is 10 inches in diameter, and the wheel o 16 inches; therefore in ten
revolutions of the boring bar, the wheel p will perform sixteen revolutions on
its axis, and at each revolution the endless screw upon its axis will move the
worm wheel q one tooth forward; and as the worm wheel has sixteen teeth, in
ten revolutions of the boring bar the screw r, to which the worm wheel is
attached, will make one turn, and will advance the cutter block through a space
equal to the space between the threads of the screw. a. is a strong spindle
screwed into the frame n, and formed with a conical point, which is received
into a conical steel bush in the centre of the head of the boring bar, and prevents
the bar from rising.
BoriNG THE EARTH For WATER. An economical process has been practised
of late years for obtaining water from great depths, without the expense of
sinking a well. This process consists simply in boring the earth with an auger
and other proper instruments, to a considerable depth; and in most situations
water will flow either to the surface, or to within a short distance from it; in
some places it has been known to spout to a considerable height above it. It
has long been a question whence these springs derive their supply, and how
they acquire the power of ascension. The most natural supposition is, that
they are connected by subterraneous channels with some elevated reservoir;
but this explanation is not altogether free from difficulty. These “Artesian wells,”
as they are termed, are to be met with in the middle of extensive plains, at a
great distance from any hills, and upon the sides of mountains, which require
to be bored to a great depth before the water is attained. At Mount Rouge, at
Paris, 80 feet above the level of the Seine, there is one of these wells 315 feet
deep. If, therefore, these wells be supplied from an elevated reservoir, it must
lie at a very considerable distance from the wells. The implements made use of in
the process are extremely simple, and are represented in the engraving on the
following page. A is the cross handle of the borer, for twomen to work; B the chisel
borer, which is made to screw into A; C the auger, which also screws into A; D a
lengthening rod, having at one end an external screw fitting the screw of A,
and at the other end a hollow screw like that in A, so that all the instruments
which fit into A may, as occasion requires, be screwed into the lengthening
piece D. A great number of these lengthening rods are kept in readiness,
which can be screwed one into the other, so as to descend to the depth of
several hundred feet. E a forked iron, used to lay across the hole to support
the rods at the joints, while the pieces are being screwed and unscrewed; F a
spanner, used to screw on and unscrew the various tools and lengths of rods;
G a clearing chisel, with a probe or piercer attached to guide it; H a spring
bar, used to produce a vibrating up-and-down motion to the chisel, when used
to peck away hard or rocky ground; I iron chain to connect the cross handle
of the tools to the spring bar; J two men at work, boring with the chisel; K
the lower pulley of a pair of blocks, suspended to a pair of shears or a triangle
above; L the shears or compasses; M winch or crane, to work the blocks
when great weights are to be raised; O three lengths of rods, and the chisel in
the act of boring-perforation about 42 feet. As a preparatory measure, a
large hole is usually dug to the depth of seven or eight feet; at the bottom of
which a floor is formed, by means of some planks, for the men to stand on and
pace round whilst using the instruments. If the earth is very soft, the only
tool requisite is the auger C of three or four inches diameter, which is screwed
into the cross handle A, and the perforation is easily effected by the mere
turning of it round by two men, as shewn in the drawing. When the auger
has penetrated to nearly the depth of the tube, it is withdrawn, and cleared of
its contents. It is then let down again, and the perforation is in this manner
continued to the whole length of the instrument. To proceed to a greater
BORING MACHINES. 233
depth, the ſengthening rods, before described, are put in requisition. The auger
is detached from the haildle by unscrewing it ; a piece of rod I is screwed in
its place, and the auger screwed on to the rod. With the instrument thus
lengthened seven or eight feet, the boring is renewed by means of the auger, as
long as the earth is found to be sufficiently soft and yielding. Whenever it proves
otherwise, or hard and rocky, the auger is detached from the rod, and the
chisel B, which is from three to four inches in diameter at its edges, is screwed
on in its place. If the ground is not very hard, the boring may be continued
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by the chisel, by the workmen pressing upon it as they turn it round; but when
the earth is too hard to be operated upon by a chisel in this way, recourse is
had to pecking, which is done by lifting up the instrument, and striking it against
the opposing substance till it is chipped away, or reduced to powder to a certain
depth. The rod and chisel are then again drawn up, and the auger substituted
for the chisel, for the purpose of extracting the pulverized stony matter contained
in the hole. The chisel and auger are thus employed alternately where the
ground is hard and stony, the one for chipping away or pulverizing, and the
other for clearing out. As the perforation deepens, the process of pecking



234 BOTTLE.
becomes very laborious; recourse is therefore had to the spring bar. H, which is
a strong pole placed horizontally over the well, at the height of three or four
feet from the ground, with one end inserted into a post or other stronghold.
The chain I is attached to this bar, and the borer is suspended by the handle
to the hook of the chain which supports its weight; a slight vertical motion is
then given to the bar by the workmen, which causes the chisel to peck away
with great rapidity. As the weight of the implements becomes too great to be
drawn up by hand, when the boring has proceeded to a great depth, the
mechanical aid of a pair of pulley blocks K is used for the purpose, which are
usually suspended from a triangle or a pair of shears fixed over the hole. The
higher these shears are the better, so as to enable the workmen to raise a great
length of rod, without unscrewing at each joint of the rod. In the manner
described the boring proceeds, changing the tools from time to time for such as
may be best suited to cut through the various strata, whether of a soft, indurated,
or stony texture, until the main spring is arrived at, when the water flows up
the newly-formed tube to the height of the distant spring from which it is
derived. If that be at a greater altitude than the surface of the earth bored,
the water rises above the ground, producing a perpetual fountain; on the con-
trary, if it be below the surface, a well must be sunk of some capacity, down
lower than the level of the spring; into this well the water flows and forms a
reservoir, and may be raised to the surface by means of a pump. The earth is
sometimes bored by the before-mentioned simple apparatus to the depth of two,
three, or four hundred feet, either for the purpose of obtaining water, or to
ascertain the presence of minerals. To carry on the operation at these great
depths, a corresponding increase of power is required, which is obtained in a
variety of ways. When the hole is bored, a pipe of cast iron or other metal is
forced down it, to prevent its being filled up again by the falling in of the
surrounding earth, and likewise to keep out the impure land springs which
might taint the water. Although the process conducted as above described is
extremely simple, it is very tedious and laborious, owing to its being necessary
to withdraw and unscrew the whole of the rods each time the earth requires to
be removed from the boring tool, and to screw them together again upon
returning the borer. To obviate these inconveniences the editor has suggested
a method by which the operation may be carried forward at great depths,
and the earth extracted without withdrawing the rods, by which also full
three-fourths of the time and labour may be saved. The means by which it is
proposed to effect this desirable object are as follows: An auger is to be made
with a spiral worm winding round a cylinder which forms its centre. The
cylindrical part is not to be solid, but perforated throughout its whole length by
a square hole of two or more inches diameter, for the purpose of receiving
within it an iron bar of the same figure and admeasurement. The bar will
thus serve the double purpose of a spindle or shaft to work the auger or cause
it to bore, and of a slide upon which the auger may be drawn up with facility
to the surface from very great depths in a few seconds of time, its contents be
discharged, and the auger be let down again as quickly, to proceed in the perfora-
tion of a fresh portion of earth. That a part of the contents of the spiral auger
may not fall out when being drawn up, the worm or thread is not to be left open,
but is to have a perpendicular border, raised upwards at right angles to the
plane of the thread; the aperture between the upper edge of this border and
the next thread is left open for clearing out the auger with facility. The
construction will be easily understood by referring to the engraving, in which
P represents the exterior of the spiral worm or auger; Q the square iron bar
passing through the square tube of the auger; R chains to draw up the spiral
worm along the bar; S top plate, to which the chains are attached; T upper
view of the plate, showing the square hole through which the bar passes; U
angular point of the square bar; V V cutting edges of the auger; W under
side view of the bottom cutting parts of the auger. Various kinds of tools may
be attached to the bottom of this auger so as to peck, &c.
BOTTLE. A vessel with a narrow mouth or aperture, used to contain
liquids; and usually composed of glass or earthen ware. Under these two
BOTTLſ. 235
heads will be found a description of the process of manufacturing them; we
shall, therefore, in this place, briefly actice some inventions coinected with
them, and which we could not introduce under separate heads.
The first is Masterman's patent apparatus for bottling wine or beer, which, as
usually performed, is a tedious and wasteful process; but by the apparatus
which we are about to describe, the bottles may be filled uniformly to a precise
point, as fast as they can be changed, without the necessity of any examination
on the part of the workman. In the annexed engraving, a is the cask con-
º
º
\
|
º |
|
taining the liquid to be bottied; this cask must be closed perfectly air tight; b a
cock, having a nozzle about 4 or 5 inches in length, and of a bore greater
than the area of the whole of the syphons, (hereafter mentioned;) c a trough
about 14 inches long, 6 inches wide, and 4 inches deep, +It is attached to the
frame d d in such a manner that its distance from the foot thereof may be
increased or dimished at pleasure; e e e e are four metal syphons, having each
a leg of nearly equal length; one leg of each is fixed to the inside of the front
of the trough, the other leg is outside of the trough about 3 inches from the
front of it; f is a trough to catch the liquid which may be spilt whilst changing
the bottles; it can be slided up and down the frame, and has a rail g for the
bottles to stand on while filling; h h represents what the patentee terms an air
tube; the cross piece i is of solid brass, bored only so high as to pass the end
of the tube soldered into it. The horizontal part of the tube is made of pure
tin, on account of its flexibility; it is connected to the vertical part by a union
joint at k; l is an iron brace placed across the trough, to retain the air tube firmly
in its proper situation. The mode of using the machine is as follows; the trough
c is fixed so high in its frame, that the bottom comes within an inch of the orifice
of the cock, and the air tube is fixed in the brace, so that its lower orifice may be at
least one inch above the orifice of the cock, and at least one inch below the top of
the trough, and the other end of the air tube is driven air tight into a hole either
through the bung of the cask, or through a hole made for the purpose in the cask
above the surface of the liquid therein. Upon opening the cock, the liquid flows

236 BOTTLE.
into the trough until it rises so high as to close the orifice of the air tube, when the
air no longer having admission to the cask, the liquor ceases to flow. The syphons
are then put in action by exhausting the air out of them successively by the
mouth applied to a bent tube, one end of which is placed against the syphon so
as to form an air tight tube within it. The outer end of each syphon, as it is
brought into action, is inserted in the neck of a bottle, and the point to which
the bottles are to be filled is brought to a level with the orifice of the air tube,
the rail g being adjusted so as to retain the bottles at this elevation. As the
bottles fill, the surface of the liquid in the trough sinks until it descends below
the orifice of the air tube, when the air rushes into the cask, and the liquid
recommences flowing; and thus by this alternate action, the liquid in the trough
is always preserved nearly on a level with the orifice of the air tube. As each
bottle fills, it is withdrawn quickly from the syphon and replaced by an empty
one; but if the bottles are suffered to remain, they will never fill higher than
the level of the orifice of the air tube, which it has been shown is the level to
which the liquid in the trough is confined. Another method of maintaining the
liquid in the trough at always the same level is described in the specification,
which we think is upon the whole preferable to that described above. It con-
sists in substituting for the air tube a species of valve, adapted to the lower
orifice of the cock, and regulated by a float on the surface of the liquid in the
trough, so that as the liquid rises in the trough, the float also rises, and causes
the valve to shut when the surface of the liquid has attained its proper level;
and as the level sinks the float also sinks and opens the valve, causing the liquid
to flow again. When the float and valve are substituted for the air tube the
cask must have vent. -
A most useful appendage to the foregoing apparatus, is the patent machine
for corking bottles, invented by Mr. J. Masterman, by the use of which all risk
of breaking the bottles is avoided; the necessity of biting the corks, (a practice
highly injurious to the health of the workmen,) is done away with, the bottles are
corked in a very superior manner, and the whole operation conducted with
cleanliness, economy, and unprecedented dispatch. The following is a descrip-
tion of the machine, (with reference to the annexed engraving,) and of the man-
ner in which it is worked: a a a a represents the frame, b b two vertical guide
rods, connected at top by the bridging piece c.; d. a cross head sliding upon the
upper ends of the guide rods, and connected by the side rod kºk, to the levers g g,
which are united at the handle h, and which have their fulcrum at i. In the
cross head d are secured by nuts on its upper face three cylindrical metal
bolts, termed by the patentee “impellers;” f is a cross piece of wood firmly
fixed to the guide rods, at such distance from their tops, as that when d is raised
close to the bridging piece c, there may be a space between the bottom of the
impellers, and the top off, at least equal to the length of a cork. In f, are fitted
three conical metal tubes, immediately beneath, and concentric with, the
impellers. These tubes have their mouths larger, and their lowerº:
smaller than the corks, and are of three different sizes, which is sufficient to
meet the variations in the size of the bottles, whether for wine or beer; l is a
treadle which, by means of the iron rod m fixed to its axis, raises and depresses
the wedge n, this wedge slides on a cross piece of wood, (firmly fixed to each
side of the frame a,) in such a manner that the upper surface of the wedge is
always preserved in a horizontal position; a loop of iron is fixed below its
thicker end, and in it the upper end of the bar m works. To use the machine,
the workman seats himself beside it with his right foot on the treadle; he then
places a bottle so that its mouth is under, and in contact with, that tube which
is of the proper size for introducing the cork into it, and retains the bottle in
that position by raising the wedge against, its bottom by means of his foot
acting on the treadle; then raising the impellers by means of the lever, he puts
a proper sized cork into that tube which is in contact with the mouth of the
bottle, he depresses the lever, by which action the cork is forced by the impeller
into the neck of the bottle; then lowering the wedge by the pressure of his
foot on the treadle, he removes the bottle, which completes the operation. This
we think is a most meritorious invention, and one deserving of general adop-
BOTTLE. 237
tion. The patentee states, that “more than half the time is saved, owing
principally to the GoiâPression of the Cork, and the impelling it into the bottſ.
being effected at one operation or motion of the lever, Twelve bottles have
been corked in one minute by way of experiment, and thirty dozen in an hour;
but one workman could cork with ease at the rate of five and twenty dozen per
hour throughout the day. The bottles also are better corked, partly owing to
the corks being compressed and compacted, instead of being crushed or broken,
as in the common methods; and partly from the corks, at the moment of entering
the bottle, being subjected to a pressure both on their tops and sides, which
causes them to become firmer and closer in the bottles, than when driven in
after being crushed by any of the common methods.
A patent has been obtained by Mr. H. Berry for forming bottle stoppers of
India rubber with the view of preventing the escape of volatile and other
fluids, which cannot be well retained by the usual means of stopping. To effect
this object several methods are described by the patentee in his specification;
that which is shewn in the engraving represents the section of an ink bottle for
H H

238 BREAD.
the pocket. a is the glass bottle with the extre-
mity of the neck ground to an angular edge, where
it is brought into contact with a disc or button of
caoutchoc b fixed into the top of the exterior case,
which is of hard wood; the top being screwed
down as shewn in the figure, the glass edges of the
bottle are forced into the elastic substance, so as to
form a close and perfectly air-tight stopper. For
volatile salts, the patentee uses the ordinary glass
stoppers, and applies a collar of caoutchoc under
a projecting flange of the stopper, which presses
upon the upper surface of the neck.
BRAKE.. In Mechanics, a contrivance for
retarding or arresting machinery in motion, by
means of friction. It generally consists of a sim-
ple or compound lever, pressing forcibly upon the
periphery of a broad wheel fixed upon one of the
shafts or axes of the machine.
BRAN. The inner husk or skin of wheat,
which is separated from the flour by the boulting machine. It is employed in
the manufacture of starch, and also by dyers in making what they call the
sour water with which they prepare their several dyes.
BRANDY. The spirituous liquor obtained by distillation of wine, and
which, by further concentration, may be converted into alcohol. The best
brandy is made in France; that made in Spain and Portugal is distinguished
by an acrid and disagreeable taste.
BRASS. An elegant yellow-coloured compound metal, consisting of copper
combined with about one-third of its weight of zinc. The best brass is made
by cementation of the ore of zinc with granulated copper. See ALLoy.
BRAZIL WOOD. A red-coloured wood, chiefly used in the process of
dyeing. The tree that affords it is the growth of the Brazils, in South America.
The wood is capable of a good polish, and is so hard that it sinks in water Its
colour is pale when newly cut, but it becomes deeper by exposure to the air.
The various specimens differ in the intensity of their colour, but the heaviest is
reckoned the most valuable. It has a sweetish taste when chewed, and is
distinguished from red sanders or såndal, by its property of giving out its
colour to water, which this last does not. If the Brazil wood be boiled in
water for a sufficient time, it will communicate a fine red colour to that fluid.
The residue is very dark coloured, and gives out a considerable portion of
colouring matter to a solution of alkali. Alcohol extracts the colour from
Brazil wood, as does likewise the volatile alkali; and both these are deeper
than the aqueous solution. The spirituous tincture stains warm marble of a
deepish red, inclining to purple, which on a greater heat becomes violet; and if
the stained marble be covered with wax, and considerably heated, it changes
through all the shades of brown, and at last becomes fixed of a chocolate
colour. The colours imparted to cloth by Brazil wood are of little permanence.
A very minute portion of alkali, or even soap, darkens it into purple. Hence
paper stained with it may be used as a test of saturation with the salts. Alum
added to the decoction of this wood occasions a fine crimson red precipitate or
lake, which is increased in quantity by the addition of alkali to the liquor. The
crimson red colour is also precipitated by muriate of tin, but it is darkened by
the salts of iron. Acids change it to yellow, from which, however, solution of
tin restores it to its natural hue. A strong decoction of Brazil wood, with as
much alum as it can dissolve, and a little gum, forms a good red ink; some
manufacturers add cochineal to give the colour more permanence and brilliancy:
good red ink may, however, be made without this addition.
BREAD, Various preparations of farinaceous substances bear this denomi-
nation; but those which are chiefly used in this country may be distinguished
into three principal kinds. In the first, called unleavened bread, either flour
and water alone are mixed, or with the addition of some other substance, such

BREAD. 239
as butter, eggs, sugar, and afterwards baked, by which the mass is reduced into
a solid state, sonictimes flakey, but never cellular or spongy. Biscuit, or sea-
bread, is of the unleavened kind, for the process of making which see Biscuit.
In the second kind of bread, called leavened bread, the flour and water being
mixed together, is either left for some hours in a thin and almost liquid state
to ferment, that the saccharine matter contained in the flour may be spontaneously
changed into alcohol and carbonic acid gas, which expand by the heat of the
oven, and render the bread vesicular or spongy. Although this intestine change
will take place naturally at the temperature employed in the vinous fermentation,
it is usual to add certain substances, termed ferments, of which the barm of
beer, or yeast, is preferred, where it can be obtained. These accelerate the
fermentation of the dough, and cause it to take place simultaneously throughout
the whole mass of dough. In the third kind of bread, a vesicular appearance
is given to it by the addition to the dough of some ammoniacal salt, (usually
the sub-carbonate,) which becomes wholly converted into a gaseous substance
during the process of baking, causing the dough to swell out into little air
vessels, which finally bursting, allow the gas to escape, and leave the bread
exceedingly porous. Mr. Accum, in his Treatise on Culinary Poisons, has
stigmatized this process as “fraudulent,” but, in our opinion, most unjustly.
The bakers would never adopt it but from necessity : when good yeast cannot
be procured, it forms an admirable and perfectly harmless substitute; costing
the baker more, it diminishes his profit, while the consumer is benefited by the
bread retaining the solid matter, which by the process of fermentation is
dissipated in the form of alcohol and carbonic acid gas. To persons un-
acquainted with the nature of the flour of wheat, it is necessary to state that it
is composed of three distinct substances, which are easily separable by art:
first, a mucilaginous saccharine matter, soluble in cold water; much starch,
which will scarcely combine with water without the aid of heat; and an elastic
adhesive grey substance, called gluten, which is insoluble in cold water, alcohol,
oil, or ether, and resembles an animal substance in many of its properties. To
the gluten in wheat flour is supposed to be owing its property of making so
tenacious a paste, and its peculiar facility of rising or expanding by the addition
of leaven. From the flour of barley, rye, oats, or potatoes, no gluten has been
extracted, probably from their containing too small a quantity; and as these
substances are very difficult of fermentation by any of the ordinary processes,
it has been supposed that the presence of gluten is the cause of fermentation.
It is, however, more reasonable to suppose that the tenacious dough formed by
the admixture of gluten prevents the escape of the gaseous products of the
fermentation, and that these, by their expansion, swell the dough into a
vesicular mass, producing what is technically called light bread., M. Beccari,
of Bologna, and Dr. Cullen, inform us that by the addition of gluten to barley
and potatoes, they produced better bread from each than could be obtained
without this addition. Parmentier asserts that bread may be made from
potatoes alone; but Mr. Edlin and Dr. Pearson, two very enlightened experi-
mentalists, state decidedly that this root cannot be fermented so as to make
bread, without the addition of wheaten flour; and that no farinaceous substance
can be made into good bread that has not the three constituent parts of wheat
before-mentioned: for if to the starch of potatoes some of this glutinous
substance be added, with yeast and water, it will not form a bread, owing to
the absence of the saccharine or sugary extract on which the process of fermen-
tation depends, and which, if this last substance be added, even in a concentrated
state, will immediately commence. Although we have no knowledge of Par-
mentier's process, we believe that his assertion is perfectly correct; for since
the experiments were made by Mr. Edlin and Dr. Pearson, the farina of potatoes
has been converted, on a great scale, into sugar and alcohol; and it has been
long known that potatoe starch may be transformed, by the application of dry
heat, into a species of tapioca, of great tenacity and elasticity. . With such
materials, we should imagine the skill of a Parmentier would hardly be necessary
in order to make good bread. In the making of leavened bread without the
addition of any article for exciting the speedy fermentation of the paste, a
240 BREAI).
great deal of attention and skill are requisite. The spontaneous decomposition
is extremely slow ; the various parts of the mass are º affected,
according to the humidity, the thickness or thinness of the part, the vicinity
or remoteness of fire, and other circumstances less easily investigated. The
saccharine part is disposed to become converted into alcohol; the mucilage has
a tendency to become sour and mouldy; while the gluten, in all probability,
verges towards the putrid state. An entire change in the chemical attractions
of the several component parts must then take place in a progressive manner,
not altogether the same in the internal and more humid parts, as in the external
parts, which not only become dry by simple evaporation, but are acted upon by
the surrounding air. The outside may therefore become mouldy or putrid,
while the inner part may be only advanced to an acid state. Occasional
admixture of the mass would of course not only produce some change in the
rapidity of this alteration, but likewise render it more uniform throughout the
whole. The effect of this commencing fermentation is found to be, that the
mass is rendered more porous by the disengagement of elastic fluid, which
separates its parts from each other, and greatly increases its bulk. The operation
of baking puts a stop to this process, by evaporating great part of the moisture
which is requisite to favour the chemical attractions, and probably by still
further changing the nature of the component parts. Bread thus made will
not possess the uniformity which is requisite, because some parts may be
mouldy, while others are not sufficiently changed from the state of dough. The
same means are used in this case as have been found effective in promoting the
uniform fermentation of large masses. This consists in the use of a leaven or
ferment (as before mentioned), which is usually a small portion of dough of the
same kind, but in a more advanced stage of the fermentation. To prepare an
original leaven, take 8 oz. of flour, and two pints of blood-warm water, and as
soon as the sponge begins to rise on the second day, add 1 lb. of flour, and four
pints of water; and thus proceed for a day or two more, when a mixture will
be obtained, which, being added to a quantity of flour and water intended for
bread, will determine the fermentation to take place throughout the mass in
three or four hours. It is only under peculiar circumstances that a recourse to
an original ferment is necessary; for this ferment having been once obtained,
and the dough nearly ready for baking made from it, the fermentation of the
next parcel of bread is readily put in action by reserving some of the fermented
dough or leaven, as it is called, and using it for that purpose. To preserve this
leaven from becoming sour, several methods are adopted. In the north of
England, the leaven for the next week's baking is kept fit for use by being
buried a few inches deep in a sack of flour. In Italy it is said to be kept fresh
even for three months by being buried deep in flour. The French, if they
intend to use the leaven in a few days, keep it in a warm place between two
bowls, and add every day as much flour as the leaven weighs, and a sufficient
quantity of water to restore the original consistence; but if it is not to be used
for a week, or longer, the scrapings of the kneading trough are cut into small
pieces, dried by a gentle heat, and when wanted, rubbed down with warm
water. It appears from the Scriptures, that the practice of making leavened
bread is of extreme antiquity; but the addition of the scum that arises in the
vinous fermentation of beer, called barm or yeast, seems to be of modern date,
and is now in general use throughout the north of Europe. In this country
this yeast is generally used in the proportion of a pint to a 100 lbs. of flour, and
is dissolved in the first parcel of water with which the flour is mixed, and no
leaven is used; but at Paris, and other great towns in France, the dough is
made first with leaven, and a little yeast is added to the last parcel of water,
merely to increase the sponginess of the bread. Although we have given under
the head BARM an account of the nature of this useful ferment, and various
modes of preparing it, we shall here add some further information which more
º; appertains to the manufacture of bread. If yeast is not to be
purchased, original yeast may be obtained by boiling a quarter of a peck (33lbs.)
of meal for eight or ten minutes in three pints of water, and pouring off two
pints, which is to be kept in a warm place; the fermentation will commence
BREAD, 241
in about thirty hours, at which time four pints more of a similar decoction of
malt are to be added, and when this ferments, another four pints are to be
added, and so on, until a sufficient quantity of yeast is obtained. In Edinburgh
the bakers multiply their yeast daily, by mixing 10 lbs. of flour with two gallons
of boiling water, and covering it up for about eight hours. Two pints of yeast,
made the day before, are then stirred in, and in about six or eight hours as
much new yeast will be generated as will suffice for 420 lbs. of flour. When
original yeast is prepared from malt, the fermenting wort may be added to the
flour as well as the yeast, according to Mr. Stock, whose patent substitute
for yeast is merely wort in a state of fermentation. This wort is made from
2 lbs. of malt, ; oz. of sugar, and 1 oz. of hops, to each gallon. Two gallons
of this wort are sufficient for 12 bushels of wheaten flour. The Hungarians
prepare a similar ferment for keeping all the year, by boiling in water in the
summer wheat bran (obtained in grinding for household flour,) along with hops;
the decoction soon ferments, and then a sufficient quantity of bran is flung in
to drink up all the liquid, and allow it to be formed into balls, which are dried
in a gentle heat. When wanted for use, some of these balls are broken, and
boiling water poured upon them, which, after some time, is strained off and used
to make up the dough. In like manner, the Romans prepared their ferment by
drawing off in vintage time a quantity of grape juice, while at the height of its
fermentation, pouring into it a sufficient quantity of millet flour to absorb it all,
and forming into small balls, which, when wanted, were broken, infused in
boiling water, and the whole then mixed with the dough. A similar ferment
may be prepared in this country from a decoction of raisins, which must sub-
sequently be either pressed between boards with a heavy weight, or be mixed
up with ground millet, as otherwise the strongest part of the must would remain
amongst them. In summer, the leaven, yeast, and even dough, is apt to turn
sour, and to communicate that taste to the bread; this is remedied by stirring
a few tea-spoons-full of carbonate of magnesia into the ferment or dough.
Wheaten Bread.—The nature of wheaten bread when raised with yeast has
been explained already at the commencement of this article; but the importance
of the subject demands a more exact account of the established processes em-
ployed in the manufacture. Mr. Edlin wishing to obtain every information on
this subject, procured access to a bakehouse, and has given us the following
account. “At three o'clock, they prepared to set the sponge, for which pur-
pose two sacks of household flour were carefully sifted through a brass wire
sieve. The following mixture was then prepared; two ounces of alum was first
put into a tin vessel with a little water, and dissolved over the fire; this was
poured into the seasoning tub, and nine pounds of salt were thrown in, over
which they poured two pails full of hot liquor; when cooled to 849 of Fahren-
heit, six pints of yeast were added; this composition was then stirred well
together, strained through the seasoning sieve, and emptied in a hole made in
the flour, with which it was mixed to the consistency of thick batter. Some
flour was sprinkled over the top, when it was covered up to keep in the heat.
This operation is called setting quarter sponge. In three hours two pails
full more of warm liquor were stirred in, and the mass covered up as before ;
this is termed setting half sponge. Five hours afterwards five more pails of
warm liquor were added; and when the whole was intimately blended, it was
kneaded for upwards of an hour. The dough was then cut into pieces, and
thrown over the sluice board and penned to one side of the trough; some dry
flour being sprinkled over, it was left to prove, till about three o'clock in the
morning, when it was again kneaded for the space of half an hour. The dough
was taken out of the trough, put on the lid, and cut into pieces. It was then
weighed, and 4 lbs. 15 oz. was allowed for each quartern loaf, the baker obser-
ving that a loaf of that size loses from 10% to 11 ounces while in the oven.
It was then worked up, and the separate masses were laid in a row till the
whole were weighed, and in counting them afterwards, he found they were
equal to 1633 quarterm loaves; but this circumstance is variable, as some flours
kneaded better than others. It should have been mentioned, that the fire was
kindled at two o'clock, and continued burning till near four, when the oven was
242 BiłFAD.
cleansed from dirt and ashes. The bread being put in, the oven was close
stopped till seven o'clock, when it was opened, and the bread withdrawn.”
}."y. Edlin has likewise furnished the following mode of making rolls,
as witnessed by him in a London bakehouse. “The flour was sifted and mixed
in the same manner as was done for the bread; at half-past six o'clock, they were
moulded up, and a slit was cut along the top of each with a knife; they were
then set in rows on a tin, and placed in a proving oven to rise till a quarter of
an hour before eight, when they were drawn and set in the oven which was
closed as before; at eight o'clock they were taken out, and were slightly
brushed over with a buttered brush, which gave the top crust a shining appear-
ance; they were then covered up with a flannel till wanted for sale.”
Brown Bread, called also home-made, is usually fabricated of inferior or
coarse flour, including more or less of the bran ground over again into pollard;
and the brown tint of the latter is usually heightened by the public bakers, by
the addition of the raspings of the burnt crust from other loaves. It has been
a fashion of late years to give the preference to this bread, under the notion of
its superior purity and wholesomeness, overlooking the obvious circumstance, that
its dingy colour affords a protection to the discovery of all sorts of adventitious
mixtures, besides that of dirty raspings. In making brown bread at home, the
case is of course different; but here, owing to the deficient kneading it usually
receives, it acquires an anomalous taste, which some call sweet, others sour.
Being unsatisfactory to the appetite, the good lady in the country flatters her self-
love in observing the increased appetite of her metropolitan visitors, and
ascribes it to the excellence of her home-made bread, when, in fact, it arises
from its imperfections. Brown bread retains more water after baking; hence
it keeps moist longer, but the middle usually crumbles away.
French Rolls, &c.—That extremely delicate and vesicular small bread called
French is made in the following manner. To a peck of flour sifted through a
fine wire sieve, three quarters of a pound of butter are added, and rubbed
together in a kneading trough; when these are intimately blended, two quarts
of warm milk, a quarter of a pound of salt and a pint of yeast are well mixed
with it, and a sufficient quantity of warm water to knead it into a dough; it
must then stand two hours to prove, when it may be moulded into rolls or
bricks, which are to be placed in tins, and set for an hour in the prover. They
are afterwards put into a brick oven for twenty minutes, and when drawn
rasped. .
Hºnola Bread undergoes the same preparation as wheaten bread, with
this difference, that instead of being made with fine flour, it is made of an
inferior sort, called seconds flour.
| Substitutes for Wheaten Bread.—Numerous attempts have been made to find
a substitute for wheaten bread, that should wholly or partially supply its place
in times of scarcity. With this view, the annexed table has been prepared,
by which will be seen the proportion of farina and of bran the following vege-
table substances contain.
Kind of Grain a Bushel of, Weight of Flour Weight of Bran
weighs in a bushel. in a bushel.
Barley. . . . . . . 46tb 38th 1040z. 5th 104 oz.
Buck Wheat. . . . . 46% 38 9 5 5
Rye. . . . . . . . 54 43 0 9 54
Maize . . . . . . . 53 44 0 8 10+
Rice . . . . . . . 613 60 0
Oats . . . . . . . 384 23 5 13 10%
Beans . . . . . . . 57; 43 53 12 0
Peas . . . . . . . 613 47 0 12 5
Potatoes . . . . . . 58 8 0
We shall now proceed to shew how these several vegetable substances may
be employed as substitutes for wheaten flour. *.
Barley Bread.—Next to wheat, barley is the most profitable of the farinaceous
grains, and when mixed with a small proportion of that flour, makes a much
BREAD. 243
cheaper, and as goed bread as that grain, as respects its nutritious properties;
which is attested by the numerous robust peasantry who make it their chief
sustenance. Barley is, however, made into bread without the admixture of any
other grain, and forms the principal diet of the miners of Cornwall, and of the
rural population of many districts in this country. It is thus made: forty-four
pounds of barley meal are kneaded up into dough, with water, yeast, and salt,
and divided into eight loaves; when thoroughly baked, drawn out of the oven,
and left to cool, they weigh about 60 pounds. Such food must, however, be
heavy; and to remedy this defect, it is always best to set the sponge with
wheat flour altogether, as barley flour does not readily ferment with yeast;
and add the barley flour when the yeast is going to be made. Barley bread
is also made by a mixture of one peck of rice to two pecks of the barley
flour: also, by the addition of 14 pounds of the drained pulp of potatoes,
to the same weight of barley flour; knead into dough with warm water and
3. * quantity of yeast and salt, and give the mass time to prove before
baking.
Buck-wheat Bread.—Buck-wheat is so little used as an aliment in this coun-
try, that there is little opportunity of studying its effects; but from all appear-
ance, it has the common quality of other grain. . In Norfolk it is grown for
fattening poultry. In France, it is made into bread for human sustenance.
This grain is covered with a hard, black, triangular husk, of which it is deprived
by an operation, previous to grinding the farina. It is effected by high
drying the grain either by the sun's rays, or by the heat of a kiln, and after-
wards by being what is technically called run through the mill stones; the husks
are then blown away by a winnowing machine, and the residual grain treated asin
the preparation of wheat corn. The manner of making bread from it alone is as
follows : boil a gallon of water, add thereto by degrees a peck of buck-wheat
flour, constantly stirring it, to prevent lumps forming, till a thick batter is
formed like that of Scotch or Yorkshire pottage. Add some salt, and boil the
mass for an hour and a half. Then pour into an iron kettle, hanging over the
fire, the due proportion for a cake, and bake it, turning it frequently to prevent
burning. An excellent mixed bread is made by the addition of a peck of wheat
flour to the before-mentioned quantity of buck-wheat. After the latter has been
made into batter, and cooled down to blood-heat, it may be poured into the
trough containing the wheat flour and yeast; being there well kneaded, it
should stand two hours to prove, divided into loaves, and baked rather longer
in the oven than for wheat bread alone.
Rye Bread.—Bread from rye alone is not, we believe, eaten in this country,
though in many parts of the north of Europe it is the ordinary diet of the
people; a mixture of rye and wheat, however, forms excellent bread, and is
very sweet and nutritious. To make the bread, knead together equal parts of
wheat and rye flour, with a sufficient quantity of yeast, salt, and warm water;
it should be covered up warm to ferment and prove, divided into loaves, and
baked in the usual way. A mixture of rice with rye makes good bread, in the
proportion of 15 pounds of rice to 60 pounds of rye. It is to be fermented
with yeast, &c. kneaded, formed into loaves, and baked in the usual way: the
product will be at the least 120 lbs. of bread.
Maize, or Indian Corn Bread.—Some authorities inform us that one half
maize, and one-half barley, with a leaven of wheat flour, of one-fifth of the
total weight, form a bread that is extensively eaten in the United States of
America and in many parts of Europe; but that a superior bread is made with
an equal quantity of wheat flour and maize. The late Mr. William Cobbett
(to whom this country is indebted for the successful culture of a species of
Indian corn,) directs the bread to be made of only one-third maize to two-thirds
of wheat or rye flour. “Set your sponge,” he says, “with the wheat flour
only. As soon as you have done that, put the water (warm in cold weather.
and cold in hot weather) to the corn flour, and mix the flour up with the water,
and there let it be for the present. When the wheat sponge has risen, and has
fallen again, take the wetted-up corn flour and work it in with the wheat sponge,
and with the dry wheat flour that has been round the sponge. Let the whole
244 BREAD.
remain fermenting together for about half an hour, and them make up the
loaves, and put them in the oven.”
Rice Bread.—Boil a small quantity of rice in water until it becomes very
thick and glutinous; with this solution knead up the rice flour in the trough,
to which is to be added sufficient yeast and salt. The dough being then covered
warm with cloths, is suffered to stand till it rises. During the fermentation,
this paste, which, when kneaded, was quite firm, becomes so soft and liquid as
to render it necessary to be put in some shallow vessel, like a stew-pan, having
a long handle, by which it is to be turned over in the oven, having first covered
the rice paste with a sheet of paper; the heat of the oven operates so quickly
upon the paste, as to cause it to retain the form of the vessel whence it was
discharged. In this manner pure rice bread may be made ; it is of a fine
yellow colour, and of an agreeable taste. Its nutritive properties are sufficientl
attested by the well-known fact that whole nations live entirely upon it. Rice, with
a great variety of mixtures, produces excellent bread. The following combinations
have been successfully employed: First, to half a peck of rice flour add one
i. of wheat seconds flour; mix with yeast, salt, &c.; knead, ferment, and
ake in the usual way. Second, to a peck of rice, boiled over-night till soft,
and which in the morning will be found considerably swelled, add a peck of
potatoes well mashed into a fine pulp, and a peck of wheat flour; a sufficient
quantity of yeast and salt being added, and the whole kneaded, it may be left
two hours to prove, before making up into loaves and baking.
Oat Bread—Take a peck of oatmeal and an ounce of salt; stir them up into
a stiff paste with warm water; roll it out into thin cakes, and bake in an oven,
or over the embers. The Scotch peasantry live chiefly on this bread, though in
some cottages they cause it to undergo a fermentation by sour leaven, which
renders it more spongy and easy of digestion. Dr. R. Pierson has recommended
the following as a good and economical bread: To a peck of oatmeal add the
same quantity of seconds flour, and half a peck of potatoes skinned and
mashed; knead up into a dough with yeast, salt, and warm milk; make up
into loaves, and bake in the usual way. Equal quantities of oatmeal and rice
flour made up the same as the foregoing in other respects, is stated to be
very palatable, and must of course be very wholesome.
}. Bread.—Bean flour does not essentially differ from other farina, but
it has an unpleasant taste; this is, however, scarcely perceptible if the flour be
steeped in water before it is used for making into bread. This flour, so treated,
made up into cakes or bread with yeast and salt, is tolerable; but a good bread
with a mixture of wheat and bean flour is thus made: Soak the flour for three days
in water before it is required, changing the water every day, to carry off .
peculiar flavour of the bean; then put the flour to drain over a sieve; during
this operation put a peck of wheat flour into the kneading trough, and mix it
up with yeast and salt. After it has been properly fermented, knead the bean
flour with it into dough, and after it has stood a sufficient time to prove, divide
it into loaves, and bake.
Pea Bread may be made in the same manner as directed in the foregoing
article for beans; it is sometimes mixed up with oatmeal and made into cakes;
but equal quantities of pea flour (that has been steeped), potatoe flour, and
seconds wheat flour, afford a good bread. The sponge should be set with the
wheat flour, and after fermentation the other flours kneaded in, allowed time to
prove, then divided and baked.
Potatoe Bread.—Pare the potatoes, boil them well, beat them to a pulp, and
knead with double their weight of wheat flour, adding a sufficient quantity of
yeast and salt; ferment, make up, and bake. The introduction of potatoes in
moderate quantity into the best wheaten bread is by no means prejudicial to
its quality. We believe that most persons find such bread, when well made,
more palatable than that which contains none. It is not quite so dry, when new,
as wheat flour alone; it retains its moisture much longer, and will keep for ten
days without any trace of sourness. The following is the process employed by
most bakers for introducing them : A cask is prepared by boring holes in its
bottom; and the bottom made to fit into the mouth of a boiler containing water
BREAD. 245
If the quantity of flour to be baked be four cwt., the quantity of potatoes that
can be properly used is five stone. The potatoes are thrown into the cask, a
cover is applied, the water is made to boil, and the steam ascending through
the holes of the cask boils the potatoes. The boiling is continued until the
potatoes crack and become mealy. They are then withdrawn, and are pounded
with a wooden instrument until they become quite fine. While this potatoe-
meal is still very hot, cold water is added in such quantity as to reduce the
whole to the thickness of butter milk. To this liquid, still warm, a gallon of
yeast is to be added. A fermentation commences; and after it has continued
sufficiently long, during which the potatoe-meal rises to the top and forms a
tough mass, the whole is to be ºft mixed; and being now a homogeneous
liquid, it is to be strained, first through a coarse hair sieve, and afterwards
through a finer. To this strained matter, one half of the whole quantity of
flour is to be added, and well worked up with the hands so as to form sponge.
When the sponge has duly fermented, the other half of the flour is to be added,
along with some more water holding salt dissolved: this mixture is to be
worked up into dough, and treated in the usual manner. An extremely light
and beautiful bread is made by the introduction of the pure starch of the
potatoe, in various proportions (to the extent of one fifth part), to wheaten
flour. The best mode of separating this starch from the root with which we
are acquainted, is by the employment of a simple machine that we contrived
for the purpose many years ago, engravings of which are given in the next
page. Fig. 1 represents a vertical section of the machine. Fig. 2 is a perspective
view of the grinding cylinder, with a part of the perforated covering turned
back, to show the internal construction; a a is a strong square frame or stand,
made of wood; b, a square cistern containing water, under which the grinding
cylinder c is partly immersed ; this cylinder, shewn separately in Fig. 2, is 11
inches in diameter, and 24 inches long; it is covered with a sheet of iron e,
perforated throughout with small holes, produced by means of a steel punch,
having a quadrangular pyramidical point, which raises four distinct burs or
teeth, particularly adapted to the purpose of rasping; this perforated plate is
mailed to the peripheries of four turned discs of wood, which thus produce the
cylindrical figure, and each disc has a series of large holes d made through it,
for the free passage of the water throughout the cylinder. The axis is mounted
in plummer blocks, fixed on the frame, (not seen in the drawing,) and is turned
by a winch handle f or any other convenient means. G is a fly wheel, to
equalise the motion. The potatoes are put into a hopper h, the lower extremity
of which is formed into a square frame which encompasses the upper half of the
cylinder in an exact manner, but not so as to touch it, in order that it may
turn round freely. The hopper is also provided with a movable curved por-
tion i, turning upon a joint, and serves to press the potatoes r against the cylin-
der, as the latter is turned round by the agency of a lever k, on which a
weight is suspended,—a traversing weight to vary the pressure. The curved side
of the hopper is made of sheet iron, and has a long slit in the middle to allow
the lever k to traverse, and as a guide to it. In setting this machine to work,
the hopper is to be filled with potatoes washed perfectly clean, and the cistern
is to be about two thirds filled with water, or so that the cylinder dips two or
three inches into it. The weight being then applied to the lever k, the opera-
tion of grinding is commenced, and continued until the cistern is nearly filled
with the pulp; but before this takes place, the water in the cistern rises so
much that a portion of it must be run off, or ladled out into another vessel, as
the water which is not then clear contains a portion of the finest starch, that
takes an hour or more to subside. The grinding of a bushel of potatoes into
pulp by a machine of this size takes a man about a quarter of an hour, from
which fact it will be seen, that one horse power is adequate to the reduction
of about 24 bushels per hour. The next process to grinding down is the sepa-
ration of the starch from the fibre, and other extraneous parts. For this pur-
nose, the cistern, which is upon rollers, is drawn forward out of its situation
about 6 inches, which allows sufficient room for the pulp being emptied out by
means of a bowl into a sieve; or instead of the latter, into a piece of lawn
I I
246 BREAD.
stretched over a tall tub, (the best form of which is, that of the inverted
frustrum of a cone;) the lawn being tied down by a cord passing round
beneath a hoop on the top of the tub. The operation is thus performed; a bowl-
ful of the pulp is first thrown on the strainer, (which is rendered concave by
the pressure,) and immediately another bowlful of clear water, from a reservoir
at hand, is dashed down upon the former; the dilution which it thus receives
causes the starch to pass rapidly through the strainer, this effect being increased
Fig. l.
º:H:
P.
*
25
(E
Q
|
º:
º
by the operator continually stirring up the mixture with his left hand. A
small portion of starch remains after the first affilsion, but which is entirely
removed by a second dose; the fibrous remains are then cleared off the strainer,
and a fresh portion of the pulp from the cistern is thrown on the filter, and
treated as the former, and the operation thus continued until the cistern is
emptied. . The cistern is again filled with water as before, the hopper reple-
nished with potatoes, and thus the grinding and washing away of the º is
alternately performed : this variation in the process affording the man an










BREAD. 247
agreeable change from the labour of turning the mill. It is advisable to use
iwo tail tubs iike that already described, aid to employ them alternately;
which will afford sufficient time for the starch to settle at the bottom of each
in a solid cake, while the process is being continued with the other tub. About
four inches above the bottom of each tub there should be a stop-cock to draw
off the supernatant liquid, which is of a reddish brown colour. The starch
should next be removed from the bottoms of the tubs, (as it is inclined in warm
weather to undergo very soon the acetous fermentation, whilst wet, with the
coloured water deposited between its particles,) and placed in large glazed
pans, wherein it should be washed or stirred up again with fresh water, and
allowed to settle again in solid cakes; and this operation should be repeated
until the water runs off colourless, which will usually be at the third or fourth
time of drawing off. The starch then settles quickly into a firm and beautifully
white cake. It has next to be dried, which is preferably done in the open air,
or exposed to the rays of the sun, in a situation free from dust. The mass
should be made into lumps with the fingers, and spread out on rectangular
frames of wood, over which is stretched any cheap cloth: these, from their
form, are very portable, and stand well upon one another, like the frames
used by glue boilers for drying their manufacture. When thoroughly dry,
it may be stowed away into casks; and if kept unexposed to damp, may be
preserved good for a century. In constructing an apparatus for conducting this
manufacture on a large scale, many improvements on the foregoing might be
made to expedite the work and facilitate the labour, which are too obvious
to need our entering further into the subject. It is, however, due to Mr. Whately,
of Cork, to observe that that gentleman had invented a machine very similar to
the foregoing, some time previous to its publication, but unknown to the author.
The difference between the two machines is quite immaterial, excepting that in
Mr. Whately's the grinding cylinder works out of water, which renders it liable
to clog up,-am effect which is prevented by the arrangement of the other. In
a communication made by Mr. Whately to the Society of Arts, (who presented
him with their honorary gold medal for the invention,) he states, that “it is
capable of the most satisfactory proof that the same quantity of land will yield
above one-half more of farina, or flour, where potatoes are cultivated, than if
the same quantity of land was applied to the production of wheat.” He further
states, “I have proved from experiment, that 2,619 lbs. of pure farina, or flour,
may be produced from an acre of land planted with potatoes, and only 1,600lbs.
of flour from an acre of wheat. It will therefore be obvious, that if we can
apply this great excess to the same purposes as the flour of wheat, the advan-
tages arising from it will be of the greatest importance to the community.” It
is, besides, well known that many poor light soils, which are considered unfit for
the cultivation of wheat, will produce good potatoes abundantly. The cost of
producing potatoe flour from the root, Mr. Whately estimates at only half that
of obtaining the flour from the wheat. In the introduction of a small portion
of potatoe i. in the manufacture of sea-biscuit, it is said the quality is mate-
rially improved, and that they will keep good for a much longer period of time;
and it may be fairly urged, that if potatoes in the gross improve (as it is gene-
rally admitted they do) the quality of wheat bread, that they must be still
more beneficial when deprived of the refuse matter they contain. This article
is, nevertheless, considered legally as an adulteration of bread, as well as many
others, some of which we shall proceed to notice. The most common sophis-
tication in bread is alum. Some writers state that as much as 4 oz. are put
into every quartern loaf by the public bakers; but bread containing so large a
quantity could not be eaten without serious constipation. From the best
information afforded to us, we are inclined to believe the quantity of alum
varies with the quality of the flour, the worst flour receiving the most alum to
improve the colour; and that the quantity put to a sack of flour (though it
varies from 4 oz. to 4 lbs.) is usually about 2 lbs. ; and as this will assign to each
4 lb. loaf nearly 4 oz., it is very probable the before-mentioned statement of
4 oz. to each loaf arose from an uncorrected error of the press. It has been
asserted that bones burned to whiteness, and ground to an impalpable powder,

248 T}REAKWATER.
are used to adulterate thirds flour; this we trust, however, is a very rare occur
tence. Chalk and whiting, in small quantity, are also, it is said, sometimes
mixed with flour. Salt, although a necessary ingredient in bread, is sometimes
added to such an excess that it becomes an adulteration; the object attained
by it is the causing the bread to retain a portion of the water which, without
it, would be evaporated in the process of baking. If bread contain an unusual
proportion of starch, it absorbs and retains more water from that cause. Such
bread, therefore, is deficient in solid matter, and is technically termed hungry
bread, as an equal bulk and weight does not satisfy the appetite like bread
which holds less water. The bakers prefer flour that has been made about
three months, or such a mixture of old and new flour as will make an equi-
valent. Weak inferior flour requires the dough to be made up as dry as
possible. If the usual quantity of water required for the best flour be used,
there is a liability to the fermentation running into the acetous stage, which of
course renders the bread sour. In all cases, if the dough has been made too
soft, it should be cooler than usual, otherwise the high heat of the oven quickly
forms a crust imperviable to vapour, and thus locks up the water in the bread.
Bread in this state is very common amongst the home-made, for want of due
experience in the operator. In the employment of flour made from wheat that
has undergone germination, it becomes necessary to have recourse to some
extraordinary means to render the bread light. Mr. E. Davy, who made many
experiments with a view to determine the best remedy for such malted flour,
ascertained that the carbonate of magnesia of the shops, when well mixed with
the new flour, in the proportion of from 20 to 40 grains to 1 lb. of flour, materially
improves it for the purpose of making bread. Loaves made with it rise well in the
oven; they are light and spongy, and keep well. To the worst flour as much as
40 grains may be added to 1 lb. of flour. Care should be taken to mix them inti-
mately together. When too little yeast has been added to the dough, the fermen-
tation is slow and incomplete; when it has been added in too great a quantity,
the fermentation becomes too rapid, and renders it liable to sourness; to remedy
which, Mr. Chaptel has recommended the kneading up some carbonate of potash
with the dough, which neutralizes the excess of acid. Dividing the dough into
small masses, and exposing it to the air, also has a tendency to check the fermen-
tation. Under the several heads of CoRN, Dough, MILL, Oven, &c, a variety of
improvements in the mechanism and processes of making bread will be found.
BREAKWATER. An artificial wall or rampart carried nearly across the
mouth of an open harbour or bay, to protect vessels moored behind it from the
violence of the sea. The two most celebrated structures of this kind are those
of Cherbourg and Plymouth. The breakwater at Cherbourg was commenced
about the year 1783 : it was to consist of a series of truncated cones of timber,
approximating at their bases, and presenting to the sea, as they rose to its
surface, alternate obstacles and openings. The number of cones, as originally
projected to cover a front of 2,000 toises, was ninety, which were after-
wards reduced to sixty-four; but this number was never completed. Each
cone was to be 150 feet in diameter at the base, and 60 feet at the top, and
from 60 to 70 feet in height, the depth of water at spring tides, in the line in
which they were to be sunk, varying from about 56 to 70 feet. The cones were
to be formed without bottoms, and being floated off by means of casks attached
to them, were to be towed to the spots whereon they were to be sunk; they
were then to be filled with stones to the tops, and left to settle for a while;
after which the upper part, commencing at low-water mark, was to be built with
masonry laid in pozzolana, and encased with granite stone. The first cone
was sunk June 1784, and by the year 1788 eighteen cones had been sunk,
occupying a line of 1,950 toises in length; but owing to the disasters which
had attended the progress of the works, (the upper parts of several of the cones
having been carried away by the violent winter gales,) the undertaking was sus-
pended ; in the following year three cones, then building, were sold by auction.
Subsequently a plan for casing over the whole length of the old work with blocks
of stone was so far acted upon, that in 1803 the centre of the dyke had been
brought above high-water mark, and here were placed a battery and a small
sts
BREWING. 249
garrison, the whole of which were swept away by the sea in a heavy gale of
wiiid in 1869. Small spots only of the breakwater are new visible abºve the
surface of the sea at low-water spring tides, except near the middle, where a
shapeless mass (extending about 100 yards in length) rises to the height of
from 18 to 24 feet above high water. Plymouth Sound is very much exposed;
and the heavy swell constantly rolling in is much increased when the wind
blows fresh from any point between S.E. and S.W. In the year 1806 the
improvement of the anchorage in Plymouth Sound, by the erection of a break-
water, was suggested by the late Earl St. Vincent to Earl Grey, then first lord
of the Admiralty; and in the same year Messrs. Rennie and Whidbey were
directed to report on the practicability of the plan. Their report was favourable;
but from various causes the work was not decided upon until 1811. The
method which was recommended for constructing the work was to sink very
large blocks of stone in the line of the intended breakwater, allowing them to
find their own base, and to assume those positions which gravity would permit,
and that blocks of stone from 13 to 2 tons weight would be sufficiently heavy
to resist the action of a stormy sea. The immense beds of limestone east of
Catwater, which were capable of affording stones of still larger dimensions,
were bought by government for the sum of 10,000l., and were opened on the
7th of August, 1812, under the superintendence of Mr. Whidbey: five days
after the first stone was deposited in the Sound, and on the 31st March, 1813,
the breakwater was first seen above the surface of the sea at low water. The
breakwater consists of a central part of 1,000 yards in length, and of two wings,
each of 350 yards, forming, with the middle portion, angles of 1589, the angular
points being turned towards the ocean. The transverse section is of the form
of a trapezoid, whose base on an average extends to about 290 feet; its breadth
at top 48 feet; and its average depth about 56 feet. The rise of the slope
facing the sea is 1 in 7; that of the slope facing the harbour 1 in 5. The
average depth of water is 36 feet at low water spring tides, and the breakwater
is carried about 20 feet higher, which somewhat exceeds the greatest rise of the
, tide. The whole length is now (1833) completed, and on the surface the blocks
are formed into a convenient path from end to end; but it is decided to build
or encase the upper part in solid masonry, commencing at low water mark,
and to erect a lighthouse near the centre. The quantity of limestone required
for its construction, was estimated by Messrs. Rennie and Whidbey at about
2,000,000 tons, and the probable expense 1,171,000l.
BREWING. The art of preparing ale or beer. The materials commonly
used for this purpose are malted barley and hops. The ingredients serve as
the basis of all ale and beer, and, indeed, are the only ones permitted by law;
but most public brewers, in addition, make use of a variety of other articles
to improve the appearance of the beer, or to suit the taste of their customers.
Each brewer has his own recipes for these purposes, which he endeavours to
keep secret; but many of the substances so employed are known to be of a
very noxious nature. The brewing of beer of all kinds is conducted by the
same general process; the principal variations in it depend upon the scale upon
which the operation is carried on; we shall therefore first give an outline of the
process as adapted to private families, and afterwards a description of the
manner in which the operation is conducted in public breweries on a large
scale. The method usually followed in brewing on a small scale is as follows:
The malt coarsely ground, or rather crushed, is strewed evenly over the bottom
of a broad tub, called the mash-tub, which is furnished with a wooden spigot
or cock, near the bottom, over the inner end of which is fitted a strainer of
basket-work to keep out the grains. A quantity of water, proportioned to the
quantity of malt and the strength intended for the beer, is then boiled in a
copper, and afterwards allowed to cool down to about 170° Fahr.; this is then
poured gradually over the malt, which is stirred all the time with a sort of rake
of a triangular form. When the whole of the water has been poured on the
malt, the tub is covered with matting or sacking to retain the heat, and the
malt is stirred from time to time. When the water has been two hours on the
malt, it will have dissolved the greatest portion of the saccharine matter of the
250 PREWING.
grain; the solution is called wort, which is drawn off into a tub beneath the
mash-tub, and another portion of water, less than the first, and at about 1800
Fahr., is poured over the malt. After this has stood for about an hour, it is
likewise j off, and may either be mixed with the former worts, or kept
separate to form an inferior description of beer. A third water is sometimes
given, which should be at 1900 Fahr. When the whole of the saccharine
matter is extracted from the malt, the remainder is called grains, and is used
for feeding pigs. The worts are then removed to the copper, and either boiled
with the hops, in the proportion of 14 lb. of hops to a bushel of malt, or (which
is a better way) an infusion of hops, previously prepared at a gentle heat, is
added to the worts, and the whole is boiled rapidly until the liquor parts, as it
is called, that is, the mucilaginous parts which were suspended in the liquor,
and rendered it turbid, separate from it, appearing like a quantity of white worms
swimming through the liquor, and if a small portion of it be taken in a glass,
the liquor quickly becomes clear, and a thick sediment is precipitated. The
liquor is then poured through a coarse strainer (to separate the hops) into
shallow tubs, placed, if possible, where there is a current of air, in order to cool
as rapidly as possible; and when it has come down to about 60° Fahr. it is
collected into the fermenting tun, and the yeast (first mixed with a small
quantity of worts) is added to the liquor, and well incorporated with it by
stirring it with a new birch broom; the tun is then covered up with cloths, and
the temperature of the room maintained a little above 600. In a short time
fermentation commences, forming a white head on the surface of the worts,
and a large portion of carbonic acid gas is evolved, accompanied by a strong
vinous odour. As soon as the head begins to fall, the beer is removed into
casks, with the bungs left out for the escape of the yeast, which comes over in
considerable quantities; the casks being replenished at intervals to compensate
for the portion of beer which is carried over with the yeast; and when the
yeast ceases to come over, the casks are first lightly, and afterwards securely,
bunged up for future consumption.
We shall now proceed to describe the process as usually conducted in a
brewing establishment on a moderately large scale. The first operation is the
proper grinding, or rather crushing of the malt; this is sometimes performed
between mill-stones, in the manner in which corn is ground, only the stones
are set rather further asunder; but of late years it has become more common
to crush the malt between two cylinders. The malt is then suffered to lie some
time in a bin or cool room, to mellow, as it is called. Grist thus exposed to the
air it is said requires less mashing, and the strength of the malt is more per-
fectly obtained. Mashing in the large way is usually performed in a circular
wooden or cast iron vessel, called the mash tun, and furnished with a false
bottom perforated with holes. Between the real and false bottom, which are
generally a few inches asunder, are two side openings; to one is fixed a pipe
for conveying hot water into the tun, and to the other a pipe and cock for dis-
charging the liquor into another vessel. The mashing is performed by machinery
invented for that purpose. These machines are variously constructed; the
following is one of the most approved description. In the centre of the tun is
a vertical axis, which is turned round by wheel-work at the top. Upon this
axis is a bevelled wheel, which turns a horizontal axis extending from the centre
to the circumference of the tun. This axis has four wheels upon it, over which
pass four endless chains, which also pass round wheels on a horizontal axis
near the bottom of the tun. Upon the endless chains are fixed iron rakes,
which, as the wheels revolve, bring up the malt from the bottom of the tun to
the top. These also receive a slow progressive motion round the tun by the
following means: the outer ends of these axes are supported in bearings in a
vertical frame, which rises to the top of the mash tun, and is braced to a collar
on the vertical shaft. On the top of this frame is a bearing, to support the
outer extremity of a horizontal shaft, on the inner end of which shaft is a
bevelled wheel, which works in another bevelled wheel on the vertical shaft.
The horizontal shaft, by means of another bevelled wheel fixed at its outer
extremity, gives motion to an endless screw, supported by a carriage attached
*
BREWING. 251
to the vertical frame, and the endless screw aeting upon a ring of teeth fixed
upon the curb of the unash tuiſ, causes ille inashing apparatus siowiy to perform
the circuit of the tun. After mashing, the tun is generally covered, to prevent
the escape of heat, and the whole remains untouched until the insoluble parts
separate from the liquor, when the wort is discharged into another vessel
usually placed beneath the mash tun, and called the underback. To extract
entirely the saccharine matter from the malt, a second, and sometimes a third,
mashing is taken, and the whole extract is received into the underback, and
thence conveyed to the copper. For heating the water and boiling the wort,
large establishments use a copper crowned with a hemispherical dome, surrounded
by a pan which will contain a succeeding wort. The liquor is generally boiled
by steam in the following way: From the centre of the dome rises a perpen-
dicular pipe, and from the upper extremity of this pipe four inclined pipes
descend, the lower extremities of which terminate near the bottom of the pan,
and consequently in the water or wort contained therein. By this contrivance
the steam which rises from the copper must bubble up through the fluid in the
pan, and speedily heat it. The advantages of this plan are, that the instant
the copper is emptied, a fresh supply of liquor can be let in to cover it,
in order to prevent the intense heat of the fire from injuring the bottom of
the copper, while the successive fluids are heated by one fire. The copper is
provided with two man-holes, fitted with lids which screw tight down. One of
these is for the purpose of admitting a man to clean the copper, and by the
other the hops are introduced; the general proportion is 13 lb. of hops to a
bushel of malt. After the first boiling with hops the liquor is let off, and the
wort is conveyed into the jack or hop-back, furnished generally with a cast iron
floor full of holes, so as to drain the wort from the hops. Then those left in the
hop-back are filled by men into tubs which are drawn up by a tackle worked by
the engine, and again boiled in the copper with the second and third worts.
From the hop-back the worts are next conveyed to the coolers. These usually
consist of several floors or stages, erected in the most airy and exposed situation
which the premises afford. They are surrounded by shallow ledges, and the
worts are pumped on to these to the depth of a few inches, and by the aid of a
current of air operating upon a very extended surface, they are in the course of
seven or eight hours cooled down to about 600, which is the average temperature
for setting to work. There are several inconveniences attending this method of
cooling: a considerable loss arises from evaporation; the process is tardy and
uncertain, depending greatly upon the temperature of the atmosphere; and the
erection of such extensive and lofty buildings as are necessary adds considerably
to the expense of the plant. To obviate these evils, many persons have pro-
posed to cool the worts by causing them to flow through thin metal pipes sur-
rounded by cold water, and many arrangements for the purpose have been
patented. The following one is the invention of Mr. Bundy. A is a tub filled
with cold water, in which is fixed a series of metal pipes, capable of cooling a
certain quantity of wort per hour, according to the size of the apparatus. The
wort may be let to run either direct from the boiler into the hop-back, or (as
convenience may permit) be ladled into B after straining from the hops. The
wort then passes from B through the main conducting pipe C into the series of
pipes, and is delivered out through the cock D into the gyle tun, adjusting the
quantity by opening the cock more or less, by which means the heat of the
wort may also be regulated, so that it may run out of the proper temperature
to be immediately fermented. The other vessel H is a longitudinal section of
a precisely similar vessel and apparatus as A, and consequently exhibits a section
of all the series of pipes, their spiral winding and situation. Now if, instead
of drawing the wort off at D, as before mentioned, that cock were kept shut,
the wort would flow out of the first series of pipes contained in the vessel A,
into the pipe F, and there ascending to its level, it would descend and be dis-
tributed through the second series of pipes at E, contained in vessel H, which
being kept constantly filled with cold water, condenses the vapours, whilst it
rapidly cools the liquid wort in its extended circuitous passage through the
convoluted series of pipes, till it is discharged at the cock G, where it arrives
252 BREWING.
properly refrigerated, in more than double the quantity in a given time than
would be delivered at D if the vessel A alone were used. A continual supply
of cold water is indispensable, which may be pumped into the tub H by passing
along the shoot I, and descending by means of the trunk K to the bottom,
which being left open, drives the water that has been made warm by the wort
in the pipes, to the upper part of the vessel, from whence it flows by the shoot
L into the trunk of the vessel A, which is similar to that in H. By these
means the water which is driven off at the º º aff
i
||f||
º
| |
top of the tub A is much hotter, and, con- || |
sequently, has deprived the wort passing |
through the pipes of much more heat than * -
in the case of the single tub A being used.
When the tub A is sufficient by itself for
the purpose required, the cold water is then
of course to be pumped into the shoot L. º
An apparatus for the same purpose, in- aſſiſſilſº
vented º Mr. Wheeler, of º Wycombe, Aº #s º $º
Bucks, is represented in the accompanying Aº tº ºt, altº
cut. A series of copper plates tinned are
first soldered together lengthwise, and
another similar series are connected with
the former, by soldering their longitudinal
edges together in such manner as to leave
between them (except at the edges) a space \ ſº
of about a quarter of an inch; they are º §º','! | |
afterwards convoluted into the form shown ! *Williº!
in the engraving, and placed in a tub or | |
cylindrical vessel; within the narrow and -
continuous chamber thus formed, the wort l ~
is made to flow from a copper or reservoir, *śl
|.
while the water or other cooling fluid runs | lº
º
in a contrary direction, by which arrange-
ment the two fluids will nearly exchange
their temperatures, the water becoming
heated and the wort cooled. a represents


BRICKS, 253
the service pipe and cock, which brings on the water from a cistern above; it
enters at the bottom of the vessel, in the centre of the convolute, from thence
passing round the coils it abstracts the heat from the wort contained in the flat
chambers, and passes off in a heated state at the upper part of the pipe b, and
descends into the trough c. The wort is received at d, the lower part of which
ipe has an opening into the narrow convoluted chamber; the wort circulating
through all these coils arrives at the centre, from whence it descends and passes
out by a pipe f in a cool state. At g there is a small curved pipe, to allow the
air in the wort chambers to escape; at h is a pipe and cock for discharging the
water in the tub whenever needful. We are not aware of any brewing esta-
blishments having entirely dispensed with the cooling stages, but several com-
bine with them the plan of cooling by water, by surrounding the pipe which
conveys the worts to the fermenting vessels with another pipe of a few inches
larger diameter, and maintaining a current of cold water through the same.
Frºm the coolers the worts pass to the large fermenting square, where the yeast
is added, and where the first fermentation is carried on. When the violence of
it begins to subside, the liquor is conveyed by a pipe to a series of circular or
square vats, ranged in double rows in a large building, called the fermenting-
house. In these vats (which are all of an equal height) the liquor purges ;
throwing up the yeast in large quantities, which, running over the tops of the
vats, together with a portion of the beer, is conveyed by drains formed between
every double row of vats, to cisterns formed to receive it. The beer which is
thus carried over is replaced by a fresh quantity from a small reservoir on a
level with the large fermenting square, and the liquor is maintained at the same
level in all the fermenting vats by means of a ball cock. When the fermentation
in the vats has ceased, the beer is in some establishments received into cisterns
of wrought stone, built at some depth below the surface, in which the beer is
left to mellow; in others it is pumped into immense vats, the heads of which
are covered with sand to the depth of a foot, to preserve them air-tight.
BRICK. A kind of factitious stone, made of a fatty earth formed into a
parallelogram about 4 inches broad by 8 or 9 inches in length, by a wooden
mould, and then baked or burnt either in a kiln or a clamp, to serve the purposes
of building. Bricks appear to have been used for architectural purposes at a
very remote period, as we learn from the Scriptures that the Israelites were
employed to make bricks in Egypt; and some of the most durable of the Greek
and Roman monuments which have come down to us, are wholly, or in great
part, constructed of this material. In the East they bake their bricks in the
sun; the Romans used them crude, only leaving them a long time in the air to
dry, about four or five years. In modern times, brickmaking is no where carried
to greater perfection than in Holland, where most of the floors of the houses,
and frequently the streets, are paved with excellent and very durable bricks.
Loam and marl are in England considered the best materials for bricks. The
former is a natural mixture of sand and clay, which may be converted at once
into bricks; marl is a mixture of limestone and clay in various proportions
The neighbourhood of London is remarkably adapted for the making of bricks,
the soil of the whole surrounding country being clay at a certain depth, gene-
rally below a bed of gravel, and the bottom of the Thames yielding the sand
which is used in this manufacture; but great practical carelessness seems to
pervade the whole business as conducted there. The following is a description
of the process as it is usually conducted around the metropolis : The earth is
dug up in the autumn, and suffered to remain in a heap until the next spring,
that it may be well penetrated by the air, and particularly by the winter frosts,
which, by pulverising the more tenacious particles, greatly assists the operations
of mixing and tempering. In making up this heap for the season, the soil and
ashes, or sand, are laid in alternate layers or strata, each stratum containing
such a thickness as the stiffness of the soil may admit or require. In tempering
the earth, much judgment is required as to the quantity of sand to be thrown
into the mass, for too much renders the bricks heavy and brittle, and too little
Traxes them liable to shrink and crack in the burning. The addition of sea-
coal ashes, as practised about London, not only inakes it work easy, but saves
H. K.
254 BRICKS.
fuel, as when the mixture is afterwards sufficiently heated these bricks are
chiefly burned by the fuel contained in the clay. When the brick-making
season arrives, the heap is dug up, the stony particles carefully removed, and
the mass properly tempered by a thorough incorporation and intermixture of
the materials, with the addition of as little water as possible, so as to form a
tough viscous paste. If, in this operation, too much water be used, the paste
will become almost as dry and brittle as the soil of which it is composed. In
order more effectually and regularly to mix the loam and ashes, it is now
generally performed in a sort of mill, named a pug mill. This consists of a
large tub or tun, fixed perpendicularly in the ground, and having an upright
bar, fitted with knives, placed obliquely. The upright bar is turned by a hori-
zontal lever, to which a horse is attached, and the soil being put in at top, is,
by the revolution of the knives, forced through a hole in the side of the tub
near the bottom, whence it is removed to the mould table, which is placed under
a movable shed, and is strewed with dry sand. A girl rolls out a lump some-
what larger than the mould will contain. The moulder receives this lump from
the girl, throws it into his mould previously dipped in dry sand, and with a flat
smooth stick about 8 inches long, kept for the purpose in a pan of water, he
strikes off the overplus of the soil; he then turns the brick out of the mould
upon a thin board rather larger than the brick, upon which it is removed by a
boy, who places it on a light barrow of a particular construction, which being
loaded with a certain number of bricks, they are sprinkled with sand, and
wheeled to the hacks. The hacks for drying are each wide enough for two
bricks to be placed edgeways across, with a passage between the heads for the
admission of the air, to facilitate the circulation of which the bricks are usually
laid in an angular direction, The hacks are usually carried eight bricks high;
the bottom bricks at the ends are usually old ones. In showery weather the
hacks must be carefully covered with wheat or rye straw, unless sheds or roofs
be built over the hacks, as is done in some parts of the country, but in London
this is impracticable, from the very great extent of the grounds. In fine
weather the bricks will be ready for turning in a few days, in doing which they
are reset more open than at first, and in six or eight days more they will be
ready for burning. In the vicinity of London bricks are commonly burned in
clamps. In building the clamps, the bricks are laid after the manner of arches
in the kilns, with a vacancy between every two bricks for the fire to play
through. The flue is about the width of a brick, carried straight up on both
sides for about three feet; it is then nearly filled with dry bavins or wood, on
which is laid a covering of sea coal and cinders (or, as they are termed, breeze);
the arch is then overspanned, and layers of breeze are strewed over the clamp,
as well as between the rows of bricks. When the clamp is about six feet
wide, another flue is made in every respect similar to the first. This is repeated
at every distance of six feet throughout the clamp, which, when completed, is
surrounded with old bricks, if there be any on the grounds, if not, with some
of the driest of the unbaked ones reserved for the purpose; on the top of all, a
thick layer of breeze is laid. The wood is then kindled, which sets fire to the
coal; and when all is consumed, which will be in about twenty or thirty days
if the weather be tolerable, the bricks are concluded to be sufficiently burned.
To prevent the fire burning too furiously, the mouths of the flues are stopped
with old bricks, and the outside of the whole clamp plastered with clay; and
against any side particularly exposed to the rain, &c. screens are laid, made of
reeds worked into frames about six feet high, and of a width to admit of being
moved about with ease. This is the mode of manufacturing the ordinary
descriptions of bricks; but the superior sort, termed washed malms or marls,
are tempered with greater care and attention. For this purpose a circular
recess is built about four feet high, and from ten to twelve feet diameter, paved
at bottom, with a horse wheel placed in its centre, from which a beam extends
to the outside for the horse to turn it by. The earth is then raised to a level
with the top of the recess, and forms a platform for the horse to walk upon.
Contiguous to the recess a well is formed for supplying the recess with water,
which is raised by a pump worked by the horse wheel. A harrow made to fit
f3R ICKS. 255
the interior of the recess, thick set with long iron teeth, and well loaded, is
chained to the beam of the wheel to which the horse is harnessed. The soil
prepared in the Heap in the usual manner is brought in barrows, and distributed
regularly round the recess, and a quantity of chalk is added, and a certain
portion of water; and the horse being set in motion, drags the harrow, which
forces its way into the soil, admits the water into it, and by tearing and sepa-
rating the particles, not only mixes the ingredients, but also affords an opportunity
for stones and other heavy matters to fall to the bottom. Fresh clay, chalk, and
water, continue to be added until the recess is full. On one side of the recess,
and as near it as possible, several hollow square pits are prepared about 18
inches or 2 feet deep. The soil, reduced to a kind of liquid paste, is discharged
from the recess by a sluice, and conveyed by wooden troughs to this pit. In
these pits the fluid soil diffuses itself, settling of an equal thickness, and remains
until wanted for use, the superfluous moisture being drained or evaporated away
by exposure to the atmosphere. The remainder of the process is the same as
for the common sort of bricks. In the country, bricks are always burned in
kilns, whereby much waste is prevented, less fuel is consumed, and the bricks
are more expeditiously burned. A kiln is usually 13 feet long by 10 feet 6inches
wide, about 12 feet in height, and will burn 20,000 bricks at a time. The walls
are about 14 inches square, and incline inwards towards the top. The bricks
are set on flat arches, having holes left between them resembling lattice work.
The bricks being set in the kiln, and covered with pieces of broken bricks or
tiles, some wood is put in and kindled to dry them gradually; this is continued
till the bricks are pretty dry, which is known by the smoke turning from a
darkish to a transparent colour. The burning then takes place, and is effected
by putting in brush-wood, furze, heath, faggots, &c.; but before these are put
in, the mouths of the kiln are stopped with pieces of brick called shinlog, piled
one upon another, and closed over with wet brick earth. This shinlog is carried
just high enough to leave room sufficient to thrust in a faggot at a time; the
fire is then made up, and continued till the arches assume a whitish appearance,
and the flames appear through the top of the kiln, upon which the fire is
slackened, and the kiln cooled by degrees. This process is continued, alternately
heating and slackening, till the bricks are thoroughly burned, which is usually
in the space of forty-eight hours. Many attempts have been made of late
years to supersede, by the aid of machinery, a portion of the manual labour
now employed in the manufacture of bricks; and although only the most recent
of the machines invented for this purpose have been found to answer in practice,
several of them are worthy of notice. The engraving on the following page repre-
sents Messrs. Choice and Gibson's brickmaking machine. a a a a is an upright
frame, with crossbeams at top and bottom; b care two vertical shafts, carrying two
horizontal spur wheels d and e, the teeth of which take into one another; these
are put in motion by the horse shaft f or any other convenient power. Near
the bottom of the shaft b is fixed a large cast iron collar g, having three deep
mortices; into each of these the end of an iron arm h is fitted, with a bolt
passing through them to form a centre, as in a hinge joint. To the other
extremity of each of the arms h is firmly fixed, by screw-bolts, a cast-iron mould
box i, having three divisions for three bricks, in which work three stocks or
false bottoms, having upright bolts passing through holes in the top. By the
revolution of the shaft, these mould boxes, with their arms, are successively
carried up and over the risers k k k, which form circular curves in the plan,
and appear so in the perspective, but are in reality inclined planes. At l, near
the bottom of the shaft, is a small bevelled wheel, which actuates a pinion fixed
on the spindle of the drum wheel m that passes under the floor of the machine;
an endless strap passing round the drum m, and another placed at the required
distance, continually carries the bricks forward to their destination as fast as
they are made, and deposited upon it. o is a crank or lever, attached by a
joint to the framing, as shown, at the upper end of which is fixed a roller; by
the revolution of the wheel above the three circular bars or cams r r r, attached
to the wheel, successively act upon the roller, and depress the crank o, which
first raises the rod and weight q, and afterwards, as soon as the crank is relieved
256 BRICKS.
of the pressure, allows it to drop and strike the mould boxes, by which the
bricks are discharged out of them. s is a box of cast iron, containing water,
into which the mould boxes dip; t is a cushion, upon which they next fall in
succession, by which the superfluous water is taken off; and j is a box of dry
sand, into which the mould boxes afterwards fall, their surfaces becoming in
consequence slightly coated with sand previous to becoming charged with clay.
The horizontal wheel e worked by d actuates the shaft c bearing the knives in
the pug mill. At the lower end of the shaft c is fixed the large circular revolving
s—ºy–
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bottom plate u, the periphery of which being furnished with teeth or cogs, as
shown, take into the teeth of a circular revolving plate v, over which, as the
mould box passes, the lower surface of the bricks becomes smoothed. At a is
a small frame, working up and down in a casing, with a pulley and counter-
balance weight, like a sash window; it is raised by the crank y as each mould
box passes, when three little boards are placed across the frame by a boy, for
the reception of the bricks. When these are deposited by the means described,


BRICKS. . . . . * . 257
the frame drops helow the level of the endless strap n; the latter then receives
them, and carries them off to their destination. At 2 is fixed a flat box, which
acts as a gauge to regulate the thickness of the stratum of clay revolving upon
the bottom plate n of the pug mill. The operation of this machine is as follows:
the clay being worked in the ordinary manner through the pug mill, it passes
out at the mouth, (not shown, being on the opposite side,) from thence under a
flap which partly regulates the quantity on the bottom plate, and next under
the gauge, which determines it precisely. A mould box having passed over the
highest inclined plane or riser k first falls on the stratum of clay, and chops out
three bricks, filling the moulds therewith by the false bottoms rising up to the
determined point from the pressure of the clay against them; the moulds, with
the bricks in them, then slide over the polishing plate r, (which is kept wet by
water constantly dripping upon it from a tub); from thence the moulds pass on
to the frame w, when the weight q strikes against the protruded bolts of the
false bottoms, and pushes out the bricks upon the boards on the frame; the
frame then descends two or three inches by their weight, and delivers the boards
upon the endless strap, which, being constantly in motion, carries the bricks
away to be deposited on the hacks. The mould box being discharged is then
carried upon its roller up the first riser k, drops into the water, thence rises again,
falls upon the cushion, next into the sand box, whence ascending again, the
highest inclined plane being duly prepared, it falls again upon the bottom plate
of the pug mill, and chops out three more bricks, during which period each
mould box has operated in a similar manner.
We shall now proceed to describe the brick-making machinery invented by
Mr. Leahy, and erected by him for the Patent Brick Company; it is represented
in the accompanying figure, a is the main horizontal shaft in direct commu-
nication with the steam engine or other first mover; b is a hopper-formed vessel,
technically termed the pug mill, in which the clay and other materials are tem-
i. and mixed up: it is for this purpose furnished with cross iron bars, or
lades of steel; part of these are firmly fixed to the hollow vertical shaft c, and
the remainder bolted to the sides of the pug mill, and they are so arranged,
that those fixed to the shaft cut in as they revolve between the others. The
clay is delivered into the hopper or pug mill by an endless chain of buckets (in
the same manner as ballast is raised in the Thames); it is then cut up and
tempered by the knives and bars in the pug mill, and gradually descending, it falls,
or rather is forced by the superincumbent pressure upon the circular inclined
plane d, which consists of a single thread or spiral turn of a very large screw,
occupying the whole internal space of the lower cylindrical end of the mill,
where it is exhibited in section. This screw or circular inclined plane is fixed to
the central shaft passing longitudinally the hollow shaft, and a slow reversed
motion is given to it, by means of an intermediate wheel acting upon pinions in
the upper part of the frame. The blades on the hollow shaft, revolve in the
pug mill at the rate of fifteen turns in a minute, grinding and dividing the
materials much more completely than in the ordinary mode of brick-making. In
this attenuated state the materials are forced upon the circular inclined plane of
the screw, and as this slowly revolves in a contrary direction at the rate of five
turns in a minute, it takes hold of the clay (by a peculiar adaptation not easily
described), and forces it out of the mill, in a very compact state, into a recep-
tacle below: of this, one side is always in immediate contact with the moulds,
and those two sides which are at right angles to the former side are closed by
iron cheeks, between which the lever or forcing flap n acts by pressure, and,
fitting closely, prevents the escape of the clay, so that it can only pass into the
moulds. These moulds are placed round the periphery of a circular frame e
made of flat iron rings, fixed upon bars or spokes, and turning upon a fiaſed
shaft. There are twenty-five of these moulding boxes in one circle; but as the
frame e may be of any breadth, it may contain twice twenty-five or thrice
twenty-five on the circumference of the cylinder, provided that the engine is
capable of affording sufficient power or force to eut or mould so many bricks at
each revolution. Each moulding box is furnished with a false or movable
bottom, to which rods are attached, for the purpose of pushing out the brick
258 BRICKS.
when moulded, and drawing back the bottom to its place to receive a fresh
portion of the clay. The manner in which these operations are performed is
extremely simple and ingenious. The ends of each of the moulding-box rods
are bent at right angles, and an eccentric piece f is so fixed, that, as the moulds
revolve, and at the moment that the surface of each is covered by being in
contact with the clay, it gradually draws back the false bottom, and with it the
clay, which is also urged on by the circular inclined plane d, and to render the
bricks solid and compact, a powerful pressure is applied to them by means of
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the flap forcer n, to which a backward and forward motion is given by the
thrusting of a rod attached to a revolving crank. The moulding boxes, imme-
diately they are thus filled, are subjected alternately to the action of a steel
scraper, which levels and smooths their surface, and is made to operate by the
pressure of springs. The bricks, now completely formed and fast in their
moulds, pass downwards in their revolution, which brings the ends of the rods
under the operation of a cylindrical roller, with grooves made round it at equal


BRICK MAKING. 259
distances; into these grooves the ends of the rods successively pass, which in
their revolution force out the rods, and thereby push out the bricks from the
moulds on to boards placed nnderneath to receive them. The bricks thus made
are carried forward to the hacks or drying house, upon an endless web or chain
i i, to which a continued motion is communicated by the revolution of the two
polygonal drums or wheels k k placed at the requisite distance asunder. The
upper part of the engraving shows a side elevation of the machine, and the
lower part a section of it; and although these views serve to give a general
idea of the construction of the apparatus, it has been impracticable to show the
gearing by which the several motions are produced; we will therefore attempt
to describe it as follows: Upon the horizontal shaft a (which makes 24 revolutions
per minute,) is fixed a toothed, bevelled wheel, which drives a bevelled pinion on
an upright shaft (not shown); nearly at the top of this a spur wheel is fixed,
which works into a pinion fixed upon the upper end of the hollow shaft c,
which carries the knives or blades in the pug mill. Upon the upper end of this
upright shaft is also fixed a pinion, which works into an intermediate pinion
turning upon an axis. This intermediate pinion acts upon another pinion
affixed to the internal shaft, communicating a slow and reversed motion to it, and
also the circular inclined plane affixed to it; at the lower end, on the main hori-
zontal shaft, is fixed a spur wheel m, which gives motion to the crank and to the
flap forcer connected to it. 0, in the separate figure, gives the form of the
shelves comprising the drying apparatus, --Mr. Leahy proposing to dry bricks
either by flues or by steam, instead of ranging them in hacks exposed to the
variations and inclemences of the weather, by which means it is presumed that
the bricks will be rendered dry enough for burning, either in kilns or clamps,
in a much shorter time than in the common method, and the process may be
carried on in winter as well as in summer. If drying by flues be resorted to,
a drying house must be furnished with proper stages, and shelves must be pro-
vided. Around and across the lower part of these, flues framed either of bricks
or cast iron are to be placed, through which flame or heated air is to be conveyed.
In drying by steam, the vapour is conveyed from the boiler through cast iron
pipes throughout the drying house, and boards are arranged upon stages (similar
to those in the separate figure), so as to leave intervals between the rows of
bricks, and to prevent their touching one another.
Nash's Patent Brick-making Machinery. This invention, which we have
now to describe, is the only one we believe that has yet been brought into suc-
cessful operation;–owing probably to the circumstance of the patentee (who is
a large tile and brick manufacturer at Market Rasen, in Lincolnshire,) having
perseveringly applied that intimate knowledge of his art which can only be
acquired by long practical experience. The leading features of Mr. Nash's
mechanism consist in the application of separate or detached moulds of a par-
ticular construction to a series of mould boxes, which are consecutively brought
into action, in the employment of heaters, placed in contact with, or contiguous
to, the fresh bricks, during the process of their being moulded; and in lieu of
sand, which is generally used to prevent the adhesion of the bricks to the
moulds, employing elastic absorbent substances, such as cloth saturated with
water. In the subjoined engravings, Fig. 1 represents a front elevation, and
Fig. 2 an end elevation of the principal parts of the machine. A vertical shaft
a is made to revolve in the cylinder or pug mill b by any adequate force acting
upon the bevelled wheel c. A number of broad steel or iron blades did d are
attached to the shaft a, their surfaces being set at such an angle as will cause
them during their revolution to pass nearly in contact with the edges of two
other sets of knives e e e fixed on opposite sides of the cylinder, by which
means the clay and other materials with which the mill is charged are tempered
and amalgamated, and then forced into the hopper f. fixed to the lower extre-
mity of the pug mill. This hopper is divided into two equal chambers by a
vertical blade or knife, which separates the materials into equal portions, which
are supplied to the moulds in a compact state. . The moulds are lodged in
rectangular cavities at equal distances in the periphery of two polygonal drums
g h; these cavities are marked 1 to 12. To one face or side of the drums are
260 BRICK Ai. KING
attached two toothed wheels, gearing into each other so as to revolve in opposite
directions when motion is communicated to one of them. These wheels lying
at the back of Fig. I cannot be seen, but one of them is shewn at i in Fig. 2.
The moulds, after being filled with the plastic material, are pushed out from their
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recesses by means of pistons at m m, easily fitting the recesses, and sliding upon
parallel rods fixed to the rims of each drum. To each piston is attached, by
a short rod, a cross head, sliding upon the parallel rods, and having at each end




BRICK MAKING. 261
small anti-friction wheels p p, which, by the motion given to the machinery,
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the pistons, and the moulds which lie upon them are then removed by hand and
emptied. During this latter process the emptied mould receiver will have passed

I, I.
262 BRICK MiAKING,
over the centre of the eccentric wheel q, and the piston will be descending when
the attendant places the emptied mould in its former situation, to be filled again
from the hopper as it passes under it. Between each of the rectangular mould
boxes are formed a series of wedge-shaped boxes, termed by the patentees
“hollow sectors,” into each of which is placed a red-hot iron, the object of which
is to expel the superfluous moisture from the newly-formed brick, &c. in order
that the manufacture may be conducted in the winter as well as the summer.
These irons are heated in the kiln fires. The axes of the polygonal drums
revolve in plummer-blocks, supported upon a strong frame s ; but as the poly-
gonal drums revolve in close contact, the plummer-blocks are free to slide in
grooves in the frame, and the wheels are kept in contact by the action of strong
helical springs t, which press against the plummer-blocks, the other end of the
springs abutting against a regulating screw. In the middle of, and underneath,
the horizontal frame s, is fixed a knife u (supported in its place by a spiral
spring), which separates the whole or a portion of the superfluous materials
from each mould, as the latter passes over the edge of the former. As some
redundancy of material may still be left after the operation of the knife u,
the exposed surface of the moulds in motion undergoes a similar treatment
from two other knives v v, fixed to the foundation plate w of the machine. A
trough or cistern k k containing water, is placed under each of the drums, the
lowest sides of which come in contact with a cylinder y, covered with strong
coarse cloth or other suitable absorbent substance, which, as it revolves, takes up
the water and delivers it to the moulds, as before mentioned. These cylinders
are mounted on elastic bearings, and derive their motion from pinions on their
axes, actuated by the toothed wheels on the drums. In the centre of the foun-
dation plate there is a cavity, or pit, for the reception of the superfluous clay or
other materials, which are removed at pleasure. The pug mill has a door in it,
for the convenience of cleaning it out when requisite; and the whole of the
upper part of the machine is supported by three columns 2 & 2. The polygonal
drums are driven by a set of wheels lying at the back of Fig. 1, and therefore
in that figure shown by dotted circles. No. 1 is a band wheel, which drives the
rest; it is affixed to one of the columns, and has a pinion 2 attached to it, that
drives a larger wheel 3, running loose on the shaft of one of the drums. This
last propels another large wheel 4, fixed on the shaft of the other drum, gearing
into each other; they are driven round together, but in opposite directions.
Since our drawings of this machine were taken, we understand that the patentee
has made some improvements in the arrangement of his driving wheel, which
renders the action of the parts very steady and uniform. In case of negligence
on the part of the boys, or other attendants of the machine, in not removing the
bricks or tiles after the moulds containing them have passed the centre of the
eccentric wheel, they fall back into their former position, and pass round to the
place of delivery, as before, without any damage whatever being done to the
machine. Having explained the general arrangement and operation of the
machine, there remains to be described the construction of the detached moulds.
Fig. 3 represents a side view, and Fig. 4 an end view, of one of these. The ends
Fig. 3.
of the mould 18, 18, are made of wood, plated at the edges with iron, and fastened
on by screws, as seen in Fig. 3. The bottom 19 is also of wood, but cased in a
strong frame of cast iron, and at its two extremities are jointed to the ends 18, 18,
so as to open only a little way, for allowing the brick to separate freely from it


BRICK MAKING. 263
upon inverting the mould. This effect is facilitated by lining the interior of the
mould with cloth, which, although constantly in a wet state, admits air to pass
through its interstices when the clay is forced into the mould, so that when the
brick is afterwards forced out, the moisture of the cloth, and the spring of the
confined air, delivers the brick uniformly clean, without the adhesion of any
clay. It will be observed that the two ends 18 of the mould have each a
cavity; these cavities receive the fingers of the workman when he takes hold
of the mould, which he afterwards inverts, drawing back the ends 18 at the
instant, and pressing with his thumb upon the screw heads 21 21, the other ends
of which are attached to a plate 22 underneath the cloth lining of the bottom,
as shown by dots, causing the brick to be immediately disengaged. The two
sides of the brick not included in the detached mould are formed by the par-
tition between the mould boxes and the hollow sectors. The forms and dimen-
sions of the detached moulds are varied according to the nature of the articles
to be produced therefrom. For adapting the machine to make tiles, or other
articles of a greater length than a brick, two movable blocks, which usually lie
inside the hopper, to contract its lower dimensions, are taken out. In the
making of drain tiles, and other articles having cavities within them, jointed
horses or cores are employed; the plastic matter is forced around them by the
action of the machine in the same manner as in forming a brick, and the sub-
sequent operations are also the same, except that in the removal or delivery of
such tiles from their moulds, suitable adaptations are made to prevent their being
pressed or even touched by the hand. The annexed Fig. 5 exhibits another
arrangement employed by Mr. Nash for making flat tiles, flooring tiles, &c.
of any required breadth and thickness. This cut only represents the lower
Fig. 5,
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part of the machine, the upper being the same as in the previously described
apparatus. . To the bottom of the pug mill is fixed a funnel. shaped hopper 23,
the materials in which, after being forced through a mouth 24, formed of the
required shape, are received upon boards 25, and when cut to the proper length,
are removed to sheds for drying. In order to equalize the surface of the clay
after it has come out of the hopper, a roller 26 turning in bearings on a curved
arm, which is fixed to a hinge joint, gives to the material any pressure that may

264 BRIDGES.
be required, by loading it accordingly. The dotted lines 27, 27 in the same
figure, exhibit another funnel-shaped hopper, for the purpose of making pipes
or tubes, by means of a centre core 28, between which and the cylindrical
continuation of the hopper, the material is forced by the action of the pug mill,
and produces a tube, which, after having made a certain length of, is cut off, the
tube being turned round, to render the inside smooth previously to its being
removed. The patentee states that this machine may be used with either one or
two horse power; that when used with one horse power, the product is about 700
per hour, or 8000 per day; to do which requires the services of two men and
eight boys, occasioning an expense not exceeding two shillings and sixpence
per 1000. With two horse power employed, the production is double, or 16,000
per day; but the quality of the bricks, which the editor has seen, is equal to
those which are usually finished by grinding the surfaces by hand. The saving
of labour in the production is about two shillings per 1000; but the quality
rendering them worth five shillings per 1000 more in the market, the advantage
of making by the machine, where good bricks are required, is equal to seven
shillings per 1000. -
BRIDGE. A structure with one or more transverse apertures, raised for
the convenience of passing a river, canal, valley, &c., and formed of various
materials, as timber, stone, iron, &c. It is highly probable that the first bridges
were composed of lintels of wood stretching from bank to bank, or, if this were
impracticable, resting on piers or posts fixed in the bed of the river; and in
China many considerable structures of this kind are still to be seen. As
experience showed the defects of these early attempts, improved modes of
construction naturally followed. In a strong current, the frequent piers or posts
necessary for the support of lintels, would, by contracting the water way, increase
it to a torrent, obstructive of navigation, and ruinous to the piers themselves.
In constructing bridges over rapid rivers, it would, therefore, be found essential
to their stability that the openings between the supporters should be as wide as
possible, and every facility given to the free passage of the water; and as this
could only be effected by arches or trusses, there can be no doubt that these
inventions were perfected before bridges became common. The most ancient
bridges which we know of, are the work of the Romans, unless we except some
of the stone bridges in China, with whose antiquity we are unacquainted; some
of these latter are turned on arches in the usual manner, and others built with
stones from 5 to 10 feet in length, so cut as each to form the segment of an arch.
The Roman bridges generally consisted of a horizontal road, supported on one
or more semicircular arches. Of the bridges of antiquity, that built by Trajan
across the Danube is allowed to have been the most magnificent. It is described
by Dion Cassius as consisting of twenty piers of squared stone, each of them
rising 120 feet above the foundations, 60 feet in width, with a water way between
every two of 170 feet, which was consequently the span of the arch, so that the
whole length of the bridge was nearly 1,500 yards. It was destroyed by Adrian,
lest it should afford a passage to the barbarians into the empire, and some of
the piers are still to be seen near the town of Warkel, in Hungary. The next
considerable Roman work of this kind is the Pont du Garde, which serves the
double purpose of a bridge over the Gardon, and an aqueduct for supplying the
eople of Nismes with water. The bridge, which consists of six arches, is 465
feet in length, and supports a second series of eleven arches, which are con-
tinued beyond the extremities of the bridge, and form a junction with the slope
of the mountain on each side; it is about 780 feet long. Over these is a third
series of thirty-five arches, much smaller than those below, 850 feet in length,
supporting a canal on a level with two mountains, along which the water is
conveyed to Nismes by a continued aqueduct. This extraordinary edifice is
built with very large stones, held together by iron cramps without cement, and
remains in excellent preservation to the present day. The whole height is 190
feet above the lower river. We may also briefly notice the bridge of St. Esprit,
near Lyons, which is of Roman origin, and is 800 yards in length; it is very
crooked, and bends in several places, forming many unequal angles in those
parts where the river has the strongest current. The bridge over the Tajo, at
BRIDGLS. 265
Valenza de Alcantara, about 25 miles from Madrid, built in the time of Trajan,
is raised 200 feet above the water, is 670 feet in length, and consists of only six
arches. Near the old town of Brionde, in the department of the Upper Loire, is
a stupendous bridge of one arch, the largest with which we are acquainted. The
span of the arch is 181 feet; its greatest height from the level of the water to the
intrados 68 feet 8 inches; and the breadth 13. It is attributed to the Romans.
The following are amongst the most celebrated bridges of modern date: The
bridge of Avignon, over the Rhone, begun in 1176, and finished in 1188. It
consisted of eighteen arches, and was about 1000 feetin length. It was destroyed
by a violent inundation of the Rhone in 1699; many of the ruinous decayed
arches still remain. The Rialto, at Venice, was begun in 1588, and finished in
1591, after a design of Michael Angelo Bonarotti. It consists of a bold flat arch,
nearly 100 feet wide, and only 23 feet in height from the level of the water. The
aqueduct bridge of Alcantara, near Lisbon, begun in 1713, and finished in 1732,
consists of thirty-five arches, of various dimensions; the eighth is the grand
arch, which is 108 feet 5 inches in the span, and 227 feet in height; the other
arches run from 21 feet 10 inches to 72 feet in width; the total length of the
piers and arches is 2464 feet. The bridge of Neuilly, which crosses the Seine,
built between the years 1768 and 1780, by M. Perronet. It is level on the top,
and consists of five equal arches, 128 feet (English), with a rise of 32 feet.
(English). The arches, which are elliptic, are composed of 11 arcs, or circles,
of different diameters. The upper portion of the arch was formed with a circle
of 160 feet radius, but after removing the centres, became flattened to an arc
of a circle of 259 feet radius, the rise of the curve in a length of 33 feet
amounting to no more than 6inches. The bridge of Orleans, over the Loire,
built by M. Hupean, between the years 1750 and 1760. It comprises nine oval
arches, described from three centres which spring at 12 inches above low water.
The centre arch is 106 feet span, with a rise of 30 feet; the others gradually
decrease in width as they approach the shores. The whole length of the bridge
is 1,100 feet. We shall now proceed to notice some of the most remarkable
bridges in our own country, beginning with those of the greatest antiquity. The
Gothic triangular bridge of Croyland, in Lincolnshire, is supposed to be the
most ancient structure remaining entire in this country, and for singularity of
construction and boldness of design may vie with any bridge in Europe. It
was erected about the year 860, and is formed by three semicircles, whose bases
stand in the circumferences of a circle, equidistant from each other, and uniting
at top. The ascent on either side of the semicircular arches is by steps, paved
with small stones, and so steep that foot passengers only can go over the bridge.
The first bridge over the Thames at London was of wood, and was built in the
reign of Ethelred II., between the years 993 and 1016; in 1163 it was repaired,
or rather rebuilt of timber; and in 1176 the late stone bridge was begun under
Henry II., and was finished in the reign of John, A.D. 1209. It had originally
twenty small locks or arches. The length was 940 feet, the height 44, and the
clear width between the parapets 47 feet. In 1758 the bridge underwent a
very extensive repair, and two of the centre arches were thrown into one. The
piers were from T5 to 35 feet thick, with enormous starlings projecting on each
side, so that when the tide was above the starlings the greatest water way was
only 540 feet, scarcely half the breadth of the river; and when the water was
below them, the water way became reduced to 204 feet, causing a most dan-
gerous fall at low water. In 1823 further repairs having become necessary, and
the obstructions which the old bridge opposed to the navigation of the river
becoming the subject of much complaint, an Act of Parliament was obtained
for the construction of a new bridge, of which we shall presently give a full
account. The longest bridge in England is that built by Bernard, abbot of
Burton, over the Trent, at Burton, in the twelfth century. It is all of squared
free-stone, is strong and lofty, and is 1545 feet in length, consisting of thirty-
four arches. One of the most extraordinary bridges in Great Britain is that
over the Taaf, in Glamorganshire, called, in Welsh, Pont y ty Prydd, built by
William Edwards, an uneducated mason of the country. Two bridges which he
had constructed at the same spot had failed; the first, after standing 23 years
266 BRIDGES,
had been carried away by a sudden and extraordinary rise of the Taaf, swelled
by heavy rains and considerable tributary streams; the second failed in con-
sequence of the ponderous work over the haunches forcing out the key stones
before the parapet was finished. Undismayed by these misfortunes, Edwards
resumed the attempt, and by means of cylindrical holes through the haunches,
so reduced their weight, that there was no longer any danger from them; and
the third bridge, which he completed in 1751, has stood ever since. The present
bridge consists of a single arch of 140 feet span, and 35 feet high, being a seg-
ment of a circle of 175 feet diameter. In each haunch there are three cylindrical
openings running through from side to side. The diameter of the lowest is 9
feet, of the next 6 feet, and of the uppermost 3 feet. The width of the bridge
is about 11 feet. To strengthen it horizontally, it is made widest at the abut-
ments, from which it contracts towards the centre by seven offsets, so that the
roadway is 1 foot 9 inches wider at the extremities than in the middle. The
bridge over the Thames at Westminster, was constructed by Mr. Labalye. It is
1,220 feet long, and 44 feet wide, and consists of thirteen large, and two small
arches. The span of the centre arch is 76 feet, that of the next is 4 feet less;
and in the others it goes on progressively decreasing 4 feet in each, except the
two small arches, which are 25 feet each. The arches are semicircular, and
spring from about 2 feet above low water mark, leaving a free water way of
870 feet. It was opened to the public in 1750, and cost 218,800l. Blackfriars
bridge was planned and built by Mr. R. Mylne, between 1760 and 1771. It is
999 feet long, and 43 feet 6inches wide, and has 9 elliptical arches. The centre
arch is 100 feet, and the four arches on either side decrease gradually towards
the shore, being 98, 93, 83, and 70 feet respectively, leaving a clear water way
of 788 feet. The cost of erection amounted to 152,840l. Numerous neat and
elegant stone bridges have since been erected in various parts of Great Britain
and Ireland. Of these we shall briefly mention the Tees bridge, at Winston,
in Yorkshire, consisting of a single arch of 108 feet span, designed by Sir T.
Robinson; one at Kiln, of five elliptical arches, of 72 feet span each; and the
aqueduct bridge on the river Lune, consisting of five arches of 70 feet span,
both by Mr. Rennie; Essex bridge, Sarah's bridge, and Carlisle bridge, each
over the Liffey; that at Aberdeen, designed by Mr. Telford; and another,
over the Dee, by the same gentleman. But the most magnificent structure
of the kind in this country, and, possibly, in Europe, is that across the
Thames, nearly midway between Blackfriars and Westminster bridges, named
Waterloo bridge. The project for a bridge at this part of the river originated
with Mr. G. Dodd, about the year 1805, but from the opposition made by
various parties whose interests were affected by the scheme, it was not until
June 1809 that an Act of Parliament was obtained, incorporating a company
for carrying the idea into effect; and Mr. Rennie having been appointed engi-
neer to the company in June, 1810, he furnished two designs, one of seven,
and the other of nine arches, the latter of which was finally approved by the
committee, and ordered to be put in execution. This noble bridge has a
level roadway, and contains nine elliptical arches, each having a span of 120
feet, and a rise of 35 feet, leaving a clear height of 30 feet above high water
spring tides, and forming a water way of 1080 feet. The length of the bridge
between the abutments is 1380 feet, and its width between the parapets 42
feet 4 inches. The roads or approaches to each end of the pier are 70 feet
wide throughout, except just at the entrance from the Strand, and are carried
over a series of semicircular brick arches of 16 feet span each. The approach
on the Surrey side is formed by thirty-nine of these arches, besides an ellip-
tical arch of 26 feet span, over the Narrow-Wall road, and a small embank-
ment about 165 yards long, having an easy and gradual ascent of not more
than 1 foot in 34.
The length of the brick arches in the Surrey approach is 766 feet.
Ditto . . . . . . . . . . . . Strand approach . .310
Length of bridge between the abutments . . . . . 1380
Total length of bridge and brick arches . . 2456 feet.
BRIDGES. 267
It should be mentioned as a proof of the excellent manner in which this
noble structure has been executed, that on reinoving the centering, the greatest
settlement did not exceed 1% inch, which is unprecedently small in arches
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of such great span. We shall now proceed to notice the New London
bridge, erected by the present Mr. John Rennie, from the design of the late
Mr. Rennie, his father, who died shortly before the work was commenced.
According to the original plan, the new bridge was to have been built on the






































268 BRIL) (, ES.
site of the old one, but the corporation of London decided that the bridge
The bridge was also made 6
ſº
should be built 180 feet higher up the stream.
feet wider, and the abutment arches carried 2
feet higher than in the original design. The
foundations of the bridge were laid in coffer
dams, and the first pile for the dam of the
south pier was laid March 15, 1824. As the
works proceeded, it was found expedient that
two of the small arches of the old bridge, on each
side, should be thrown into one, to compensate
for the additional obstruction which the works
occasion to the navigation of the river. This
was effected with such skill, that the usual
traffic was never once interrupted during the
operation, the heaviest carriages passing over
the bridge, and vessels passing through it,
with the same facility as before; whilst such
was the promptitude and despatch used, that
the whole operation only occupied six weeks.
The engraving on page 267, with the following
description, will explain the manner in which
the alteration was effected. The roadway was
first boarded in and taken up one half at a
time, and a space cleared away for the recep-
tion of a transverse iron girder A. A set of
transverse timber principals B B was then laid
on to this girder from the extreme piers of the
two arches, bestriding, as it were, the central
pier, which was to be removed ; and these,
instead of being placed at intervals as in roofs,
were all fixed and bolted close together from one
side of the roadway to the other, forming one
unbroken mass of timber. Above the girder
there was inserted what may not be unaptly
termed the brestsummer C, into which the pur-
lins D D were mortised at intervals for the
support of a substantial planking, on which
the pavement was laid as before. The strength
of the truss-work was farther augmented by a
number of counter-principals, as 1, 2, some of
the struts being fixed close together, and
others with an interval of one width between
them. The bridge itself was nearly completed
before the line of the approaches to it were
decided upon; it was at length finally settled that
the approach on the London side should com-
mence at Cannon-street, Eastcheap, passing
over Thames-street by means of a dry arch,
and that on the Borough side the road should
form an inclined plane, supported on a series
of brick arches, commencing near St. Thomas's
Hospital, with a large dry arch facing Tooley-
street. On the 1st of August, 1831, the bridge
was opened to the public, the period occupied in
its erection from the time of driving the first
pile, being seven years, five months, and
thirteen days. The engraving in the margin is
an elevation of the new bridge; it is formed of
five semi-elliptical arches, the least of which is larger than any oth
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stone arch ever before erected. The centre arch is 152 feet span, with a rise















Bitſ DG I.S. 269
of 29 feet 6 inches above high water mark; the two arches next fle centre are
140 feet in span, with a rise of 27 feet 6 inches; and the two abutment arches
are 130 feet span, with a rise of 24 feet 6 inches; thus the clear water way at
all times of the tide is 692 feet, which is above 60 feet more than the old
bridge afforded at high water mark. The whole length of the bridge from the
extremities of the abutments, is 928 feet; within the abutments, 782 feet; and
the width between the parapets is 53 feet. The engraving represents the new bridge.
Towards the close of the eighteenth century some bridges were erected, the
arches of which were gonstructed entirely of cast iron The honour of this
invention is due to this country, and the first of these structures was the bridge
over the Severn, at Colebrook Dale, erected by Mr. Darby, in 1779. Some
years after (about 1790,) the celebrated Thomas Paine had one constructed at
the same place, which he intended for America, and which was put together
in a meadow near that place; but he not being able to pay for it, it was taken
down, and part of the materials were employed in the construction of the
Sunderland Bridge, erected by Mr. Burdon over the river Wear, in 1793.
Subsequently, numerous iron bridges have been erected: the principal ones
are Buildwas (Colebrook Dale Company), 1795-6; Tame, Herefordshire (failed),
1795-6; Parret, at Bridgewater, 1796; Staines (twice failed), 1800; Tees, at
Yarm (failed); Boston, in i.incolnshire; New River at Bristol (two); Vaux-
hall Bridge, over the Thames; but the most celebrated of these structures is
the magnificent one over the Tharaes, called the Southwark Bridge, designed
and erected by the late Mr. Rennie. This noble bridge consists of three
circular arches of cast iron, supported by piers of granite; the centre arch is
of 250 feet span, and the side arches 210 feet each. The piers are 24 feet
thick. The bridge is 718 feet long between the abutments, and 42 wide
between the parapets. There is a dry arch over the road on the Southwark
side. The work was begun in 1814, and completed in 1824. The annexed cut
is a view of the centre arch.
Iron Suspension Bridges were in use in Europe at the time of Scamozzi, the
architect, who mentions them in his work Del Idea Archi, 1615; but the
knowledge requisite to determine the properties of this kind of bridge was not
published till the time of Bernouilli Suspension bridges are described as
existing in various parts of Asia, Africa, and America, before this species of
construction began to be practised in Europe. The first chain bridge erected
in England is supposed to be that over the Tees, forming a communication,
between the counties of Durham and York. Since that time the number of
these structures has been increasing, some of which, in size and magnificence,
exceed any thing of the kind in the known world. Of these, the most cele-
brated is the one recently erected over the Straits of Menai, by Mr. Telford.
The bridge consists of one opening of 560 feet between the points of suspension,
and 100 feet in height between the high-water line and the under side of the
road-way, which is horizontal. In addition, there are four arches on the western
side, and three on the eastern side of the main opening, each of 50 feet span.
M. M.

270 BRIDGES.
The roadways consist of two carriage ways, each 12 feet in breadth, with a foot-
path of 4 feet between them, so that the platform is about 30 feet in breadth.
The whole is suspended by perpendicular iron rods, from four lines of strong
cables of malleable iron, passing over a pyramidal support or pier, at each end
of the main opening, the versed sine of the curve being 37 feet, or about , of
the chord line or span. The weight of the bridge between the points of suspension,
including the weight of the cables, is 489 tons, and the suspending power being
calculated at 2,0id tons, leaves a disposable force of 1,674 tons to meet any
stress the bridge may be exposed to. The-iron bar suspension bridge erected
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over the Thames at Hammersmith, is inferior only in magnitude to the one just
described. . It was designed and executed by Mr. T. Clarke, civil engineer, and
was opened for public use in August, 1827. The above cut Fig. 1, represents
a perspective view, and Fig. 2 an elevation of the bridge, and some of the




























































BRII) GES. 271
details of its construction. This bridge consists of two suspension piers or
towers, built in the river, having an opening of 400 feet between them. On
the opposite shores are two strong abutments, over which a nearly level road-
way passes through archways I'ig. 3. *
in the suspension towers. It is o
suspended by four lines of sº
strong chains, hanging in curves
from the abutments over the
towers, and down between them,
the roadway being supported
from them by vertical rods. The
principle of construction is as
follows: D D Fig. 3, are the
suspension chains, which con-
sist of bars of iron 5 inches deep
by 1 in thickness; these are
10 feet in length, and con-
nected together, as shown in
the plan beneath, by plates of
iron having astrong bolt passing
through them, and turned at the
ends; these saddle pieces are placed ten feet, asunder, and are so arranged
that those in the upper chain are not immediately over those in the lower
chain, but over the middle space between each two on the lower chain. Fron
each saddle piece in each of the chains hangs a suspending rod C C, 1% inch
thick, so that they are 5 feet Fig. 4.
asunder. The suspending rods are ſ
furnished with a joint where they º
|
R.
|=PH
are inserted into the opening
between the chains or plates, ena-
bling them to accommodate them-
selves to any extraordinary weight
on the bridge. At the height of
about 40 feet from the roadway,
the chains pass through the ma-
sonry of the archways before men-
ſ —
\.
tioned, and over friction rollers,
and are secured to the ballast plates Fig. 4, which are sunk to a considerable
depth behind the abutments. The roadway consists of transverse beams in two
thicknesses, 4} by 12 inches, with an interval of 24 inches between them; these
L”
are fastened at the bottom by keys to strong iron plates; along each side of the
bridge extends a pair of strong beams, which are firmly bolted to the flooring
joists; this connexion is shown at E E, Fºg. 3. The roadway of the bridge is



272 BRIDGES.
slightly raised towards the centre of the river, and the whole is boarded ſon-
gitudinally with 3-inch planks, as shewn at Fig. 5, with a small space between
each to prevent any water from settling on the bridge. There are two pairs
of chains on each side of the bridge; the inner pair consists of six links or bars,
and the outer of only three, as represented in Fig. 5. The total length of the
bridge is as follows:–
Feet. Inches.
The central opening . . . . . . . . . 400 3
The two suspension towers, each 22 feet . . 44 0
The opening on the Surrey side . . . . . . 145 6
The opening on the Middlesex side g 142 11
The two abutments, each 45 feet . . . . . 90 0
Total . . . . . . . . 822 8
The towers are 48 feet high above the level of th sº TD.
roadway, 22 feet wide, and 42 feet broad. The road- *
way is 16 feet above the water, and consists of a His
carriage-way 12 feet wide, and two foot-paths, each Hiš
4 feet wide. The versed sine of the curve of the sus- |#
pending chains is 29.6. Several bridges on the
suspension principle, composed of iron wire, have
also been erected, and on a small scale will no
doubt answer; but if of great extent, the vibra-
tion becomes so great as to render them unsafe.
Some of these, instead of being suspended from
chains hanging in a curve between their points of §|N . All?
suspension, are supported by diagonal braces, pro- Sºjº-
ceeding direct from the supporting towers to
different parts of the platform forming the road-
way. The wire bridge of Dryburgh, which was
constructed in this manner, had one of its largest
radiating chains broken off at the point of suspen-
sion, by some mischievous persons shaking it vio-
lently. Shortly after it was repaired, a high wind
again broke the chains, and completely destroyed
the bridge. From the evidence of many persons, |
it appeared that in this gale the vertical motion of
the bridge was equal to its lateral motion, and was
sufficient to precipitate a person into the river.
The bridge has been since replaced by one on the
Catenarian principle. At Vienna there has been
erected a steel suspension bridge over the Danube.
The span is 234 feet, and the versed sing 15 feet.
It is the work of M. Ignace Von Mitiz, who calcu-
lates that the total weight of steel is less than half
the weight of iron which would be necessary for
a bridge of the same dimensions.
A model of an iron suspension bridge, upon a
new construction, was exhibited in the year 1829
It was constructed by Mr. Mottley as a design
for a bridge across the Thames, from Scotland
Yard, on the Middlesex side, to the King's Arms,
º
*
wº
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º
R2
on the Surrey shore. The annexed design for jº/
an ornamental bridge for parks or pleasure- {X}/
grounds, will serve to explain the nature of Mr. 2.É. §
Mottley's plan, which consists in a combination of =||
the principles of tension and compression. The | %
arch represented by the curved line is confined |%
between two parallel lines, and those lines are %
connected together by vertical bars, to which the º, ſix,


BRIDGES. 273
arch is inflexibly attached, and the parallel lines or bars also inflexibly jointed,
and the whole combined by strong bolts at the top and bottom of every vertical
bar, rendering it a skeleton of a trussed beam; thus affording an opportunity of
having two paths across a river, the lower one of which may be used as carriage
way, and the upper may serve for a footway or promenade. This second floor
is not an absolutely necessary part of the structure; but if it be not adopted, it
will be needful to have diagonal braces placed horizontally to stiffen the upper
part. By this mode of construction, it will be seen that the stress or pressure
instead of acting upon the highest point of the structure (as in the case of
bridges where the main chains pass over lofty towers) exerts its force at the
lowest point, viz. at the springing of the supporting arch, whilst the piers have
only to support the weight of the bridge, the thrust being counteracted by tie
bars, which connect the two extremities of the arch.
The accompanying engraving represents a portion of a bridge, or of a jetty,
supported upon floating piers, as proposed by Messrs. Delafons and Littlewort,
§§§ $ & * *S*S$
for situations where the water is too deep for the erection of piers, and where
the expanse of water is too great to be passed over by chains, without any other
support than that at the abutments. a represents the river or channel - to be
crossed; b the bed of the same; c the suspension bridge; d one of the floating
piers, of which there may be any number, according to the distance between
the shores; e the mooring chains, which are attached to the heads of piles
driven perpendicularly into the earth. The piers are supported upon rows of
properly constructed boats, whose buoyancy is sufficient to bear the weight, that
is, without their being submerged at low water; and these boats are confined in
this situation by the mooring chains. By this arrangement, when the tide
rises, the piers cannot ascend and lift the bridge, which would be the case were
the boats not tied down to the extreme point of low water, while the bridge is
supported by their buoyancy in either case. The machinery by which the piles
may be driven at considerable depths under water, forms the subject of a patent
taken out by Messrs. Delafons and Littlewort.
The readiest, and probably the most ancient material for the construction of
bridges, is timber; and, in most countries, wooden bridges are common; but, in
their construction, Germany and America appear to take the lead of all other
countries. The most celebrated of these structures was that over the Rhine at
Schaffhausen, which was destroyed by the French in 1799. It was designed
and executed by Ulric Grubenman, a common carpenter, who produced a
model of a bridge to consist of only one arch of 364 feet span; but the magis-
trates insisting that the bridge should, near its middle, be supported by a
pier, the remains of a former bridge at the same place, he seemingly complied,
but executed the work in such manner as to leave it doubtful whether the
bridge really received any support from the pier. John, the brother of Ulric,
about the same time constructed a timber bridge of the same sort at Kui-
chenaw, 240 feet in length; and they afterwards conjointly constructed one near
Baden, of 200 feet in length, and another at Wuttenghen, 198 feet in length.
Several timbe, bridges were erected in Germany during the years 1807, 1808
º




274 BRILLIANT.
and 1809, by Wiebeking. The widest span is that over the Regnitz, at Bam-
berg, which is 208 feet. There have been many capital timber bridges con-
structed in America. The Trenton bridge, over the Delaware, built by Burr in
1804, is a segment of a circle of 345 feet diameter, its chord measuring 200
feet, its versed sine 32 feet, and the height of the timber-framing at the vertex
only 2 feet 8 inches. That called the Colossus, over the Schuylkill at Phila:
delphia, is of the extraordinary span of 340, and is the segment of a circle of
1465 feet diameter; its versed siné being only 20 feet, and height of the wooden
framing of the arch at the vertex only 7 feet: it was finished in 1813.
Bridges of Boats are made of boats composed of either copper, tin, or wood,
fastened across the stream by means of anchors or stakes, and laid over with
planks. At Beaucaire, Rouen, and Seville, are very fine stationary bridges of
boats, which rise and fall with the tide; that at Rouen. is nearly 300 yards
long, and paved with stone, so that laden carriages and horses go over it in safety.
Another kind of bridge of boats is that called flying bridges, the use of which
is mostly confined to those rivers in which the stream is always running down.
A flying bridge generally consists of one or more boats, covered over by a platform,
and connected by a long cable to an anchor midway of the river, and considerably
higher up the stream than the landing place on either side; upon putting the
helm over to one side, the side of the boat is presented obliquely to the stream,
which impels it across the river to the opposite shore. Sometimes, instead of
laying down an anchor in the stream, two stout shears or masts are erected,
one on each bank, and firmly secured by guys. A stout hauser is then stretched
tight from the top of one mast to the top of the other. Upon the hauser is a
large iron ring or grommet, to which is attached one end of the boat rope, the
other end of which is made fast to the boat, or boats, of which the bridge is
composed. By the action of the tide upon the rudder the boat is sheered
across the stream, dragging the grommet along the hauser. The annexed cut
a'
(@)&
n
º =lſ”
{} Eºs
*** *-*.
represents another species of flying bridge, which has been proposed for
crossing valleys, rivers, &c. It consists of a strong wire chain, iron rod, or
cord ee e, which passes over the supports a a, to which one of the ends is
firmly fixed as at f and adjustable by tightening screws as at g; c is an endless
cord passing over the pulleys b b on the supports and round the pulley i, which
is attached to a light car, in which the passengers sit. The car is supported on
e e e by the pulleys h h; it is attached to the endless cord by the stem / /,
which is furnished with two holes to admit the cords at k and l. These holes
pass through the stem at right angles to each other, so that when the upper
hole k is placed in the direction of the cord, it will pass freely along it, while
the lower hole is placed across the cord, and thereby holds it fast, and the car
is dragged along by it: but if the stem be turned (which may be done by the
handle at l,) the reverse operation will take place, and the vehicle will be
dragged along by the upper cord. The endless cord may be put in motion
either by persons in the car turning the pulley at i, or by persons turning the
. ; the station f, which is connected by an endless chain or band to the
Ull LeV 0.
BRILLIANT. The purest kind of diamond; which see.

BUILDING. 275
BRIMSTONE. See SULPHUR.
1:
• * ~~~~ + r. * * iſ tº * * * * *
BRHN E. Water impi egnated with Nº Cº. i. 111 Vy particles, and is cit!;cr native, aS
in the sea and in salt springs, or it is artificially formed by dissolving salt in
Water.
BRONZE. A mixed metal, consisting chiefly of copper, with a small pro-
portion of tin, and sometimes of other metals. It is used for casting statues,
cannons, bells, and other articles, in all of which the proportions of the ingre-
dients vary. See ALLOY.
BUILDING is the art of constructing edifices, the decorative part of which
has received the more imposing name of Architecture. As the main design
of this work is, however, to furnish the most extended accounts within its
limits of the mechanism and manufacturing processes of the empire, we shall
confine ourselves to the sketching of a mere outline of this subject, and refer
the reader to those works from which he may fill up the details. The origin of
all buildings may be deduced from the construction of the meanest huts.
Small trees tied together at their tops, or connected by poles, and then covered
with such materials as nature most readily presented, as brushwood, turf, leaves,
and grass, were probably the primitive habitations, in temperate climates, of
uncivilized man; indeed, such rude fabrics are still used by various tribes of
Indians of the present day. As population increased, and agriculture improved,
it became necessary for the inhabitants of woods to seek situations in the open
country more favourable to their occupations; hence other means for constructing
their dwellings became necessary; and finding the advantage of living in society,
gradual refinements took place : amongst these, the employment of stone as
a preferable material to wood for the floor and the roof. By degrees, elegance
succeeded to, and was combined with, convenience. The earliest regular
buildings of which any information is given, were erected by the Egyptians.
The Assyrians and Persians added splendour and richness to the architecture of
Egypt, but it was reserved to the Greeks to impart to this art elegance and
symmetry; to them we are indebted for three out of the five orders of architec-
ture, namely, the Doric, Ionic, and Corinthian. The Tuscan and the Composite
orders, which complete the five, are rejected by some writers on architecture,
because they differ but little from the other three. The Tuscan resembles the
Doric deprived of some of its mouldings; and the Composite differs from the
Corinthian by the introduction of the Ionic volute into its capital. When about
to build, choice of situation is the first thing to be considered. For dwelling-
houses, a spot should be chosen sufficiently elevated to be free from damps and
noxious vapours, and, at the same time, sheltered from the severity of the
winter : the neighbourhood of fens and stagnant waters should, if possible,
be avoided. It . however, be a spot where water can be easily procured;
where drains may be made with facility; and where the principal apartments
may have the advantages of southern and western aspects. The nature of the
soil should be likewise carefully examined, by boring or sinking wells, in order
to determine if a firm foundation can be had. The situation being chosen,
attention to the various arrangements of the edifice becomes the next point of
consideration. Drawings should be prepared, exhibiting every part correctly in
plan, elevation, and section; and if it be a considerable building, a model
also. The principal difficulty in architecture appears to consist in properly
combining utility with ornament. Of course in buildings solely designed for
ornament, as columns, obelisks, triumphal arches, &c. beauty alone should be
regarded. On the other hand, in buildings solely intended for utility, every
part ought to correspond with that intention. The least deviation from use,
though contributing to ornament, is improper, and very disagreeable to persons
of correct taste. The construction of the drains to carry off the rain and waste
water should be the first proceeding; next, the foundation for the walls, in
which the utmost care is requisite that the floor on which they are made to
rest should be perfectly level and solid. When the board plat is laid, the first
course of brick or stone should be laid without mortar, for lime disposes wood
to rot, that in some soils would last for ages. After this, all the courses should
follow with the same evenness and regularity. The thickness of foundations in
l-
276 BUILDING.
general ought to be double that of the walls which they have to support. The
looser the ground, the thicker the foundation wall ought to be ; which may
be diminished as it rises, as well as the wall that is raised above it, which
diminishes the expense without reducing the strength. The doors and windows
should be proportioned to the magnitude of the building. The doors of dwelling-
houses are usually from 7 to 8 feet high, and from 3 to 4 feet wide. Builders
consider the proportion of three to seven in small, and one to two in large doors,
to be the most eligible. With regard to windows, their number and size should
be so arranged as to admit neither more nor less light than may be requisite.
Their width in all the storeys should be the same; but the different heights of the
rooms make it desirable to vary their height also ; but in this much must
depend upon the reigning taste or fashion. The windows in all the stories of
the same aspect must be placed exactly over one another. The mathematical
rule for apportioning light to rooms is as follows: multiply the length of the
room by the breadth, and multiply the height by the product of the length and
breadth, and out of that product extract the square root, which is the light
required. For example: suppose a room to be 36 feet by 24, and 15 feet in
height, the square root of the product of these numbers, when multiplied as
described, will be 1 13 feet, which, divided into four parts, will give 28 feet 3
inches to each window. A good proportion for this area is 8 feet 6 by 3 feet 4,
and so for any others by the same rules of proportion. For the construction
and proportions of chimneys, see CHIMNEY. The simplest form of a roof that
will resist the influence of the weather is the inclined plane; yet, independently
of its want of symmetry, it does not admit of the greatest strength from a given
quantity of timber. The best figure is that which consists of two inclined
planes, meeting at the top over the middle of the building in a ridge or hori-
zontal line. High pitched roofs being most suitable to the pointed architecture,
were introduced at the same time, and form one of the most striking features of
the Gothic style. This equilateral triangular roof prevailed in private as well
as public buildings till the introduction of the Roman style by the celebrated
Inigo Jones, and the consequent expulsion of the Gothic architecture. The
chief advantages of high pitched roofs are, that they throw off the rain and
snow more quickly; they may be covered with smaller slates, and are not so
liable to be injured by heavy winds; while low roofs, as they require shorter
timbers, are much cheaper, and have less pressure upon the walls. When
executed with judgment, the roof is one of the principal ties to a building, as
it connects the external walls, binds the whole into one mass, and preserves
it from the injuries and decay which would soon be occasioned by rain and
frost. Trusses are strong frames of carpentry, so contrived as to act like a solid
body, and support certain weights at given immovable points, the truss being
suspended from two such immovable points; they are generally made of a
triangular form, and placed at equal distances on the wall plates, in vertical
parallel lines, at right angles to the walls. Some excellent examples of trussing,
especially on the suspension principle, are given under the article BEAM. See
also Roof. Various methods are adopted for the construction of floors accord-
ing to the different bearing of the timbers. In small rooms the floors consist
in general of single joists, but in large rooms two rows of joists are employed,
one supporting the other above, and fixed at one end into a beam called the
girder, which is usually placed transversely in the middle of the space; if the
size of the room requires three compartments of joisting, two girders will be
needful. The upper row of joists is called bridging joists, and the lower,
binding joists. Stairs are used as the means of communication to the different
storeys of a house, and the space in which they are enclosed is called the stair-
case. The utmost attention on the part of the builder is necessary in fixing
the staircase, and in determining all its just proportions. The steps, whether of
marble, free-stone, or wood, &c., may be supported at both ends, or at one only ;
when the latter, it is usually the broadest, though in small wooden stairs the
steps are sometimes made to project from a newel, to which the narrow ends
are fixed. The height of large steps must never be less than 6, or more than
7% inches. The breadth should not be less than 10, and never exceed 18
BUILDING. 277
inches. The length of them cannot conveniently be less than 3 feet, or more
than 12 feet, Geometrical stairs have their outer cads fixed in the wall, and
the under edge of every step supported by the edge of the one below it. The upper
part of the joint may be level from the face of the riser to about 1 inch within the
joint; the plane of the tread of each step is thus continued about an inch
within the surface of each riser; the lower part of the joint has a narrow sur-
face perpendicular to the rake of the stair at the end next the newel. Geometrical
stairs constructed of stone depend upon the following principle:—that every body
must be supported by three points at least, placed out of a straight line; and
consequently, if two edges of a body, in different directions, be secured, they
will become relatively immovable; such is the case in a geometrical stair; one
end of the step is always tailed into the wall, and one edge rests either on the
ground, or on the edge of the inferior step or platform. The methods of
forming staircases are so various that it would be impossible to give even an
intelligible definition of them that would be compatible with our limits; we
shall, therefore, at once refer the reader for information on this and all the
other departments of this subject to The New Practical Builder, which unques-
tionably is the most complete modern work upon this important art, whether as
respects the plainest or the most magnificent structures.
Building en Pisé. An extremely simple, durable, and economical method of
building walls, in very general use in the neighbourhood of Lyons, and which
has been introduced into this country. It consists simply in ramming earth
firmly between moulds formed of boards set upon the ground-plan of the
walls; and although it may seem that buildings erected upon this plan must
resemble the mud cabins which disfigure many parts of this country, they
nevertheless differ widely both in appearance and durability, since they may be
made as meat as brick buildings, and equally durable, houses of 150 years
standing, built in this manner, being by no means rare in France. The follow-
ing instructions for this mode of building are taken from a paper in the Trans-
actions of the Society of Arts, Vol. XXVII. by Mr. Salmon, who has practised
it to some extent on the estate of the Duke of Bedford, at Woburn. The only
tools necessary for building en pisé, besides the ordinary ones used in building,
are the moulds and rammers. The mould consists of two side pieces, each
composed of two planks 12 feet long, 10 inches wide, I inch thick, strengthened
by several pieces of board nailed across them on the outside, at equal distances
apart. Holes are made through these pieces of board at top and bottom, to
receive iron bolts, which hold the two boards parallel to each other, 14 or 16
inches asunder, which is the thickness of the walls intended to be formed
between them. The bolts have a large head at one end, and a key passes
through the other to keep the planks together. Two boards, equal in length to
the thickness of the wall, are placed between the planks at the ends to form
the ends of the mould. The rammer consists of a short staff with an iron
head, which should not be more than half an inch wide on the edge, in order
that it may more forcibly compress the earth in every part, which a flat rammer
could not do so well. In forming the angles of a building, four mould boards
are requisite: each of the boards for the internal angle have two eye-bolts
through, and the boards being set together at the proper angle, a bolt is passed
through the four eye-bolt, forming a kind of hinge; the boards are retained in
their position by an iron stay, hooked into a staple in each of the boards. The
boards for the outer angle are connected by two short pieces of iron projecting
from one of the boards which pass through corresponding holes in the sides of
the other board near the end, and are keyed up on the outer side of the mould.
The process is conducted as follows:—the foundations of the intended building
must be laid of brick work, stone or rubble, and be carried at least 9 inches above
the surface to protect the pisé from the rain; the mould frames are then set up
on the foundation walls and bolted together, the thickness of the foundation
regulating the distance at bottom, which distance is maintained at the upper
part of the mould by pieces of wood cut to the proper length, which are laid
upon the upper connecting bolts; head boards are also placed at each end to
retain the earth. Loose earth is then thrown into the mould to the depth of
N N.
278 BUILDING.
about 3 inches, which is afterwards drawn back, and cleared from the face of
the mould, and the space filled up with a facing composition, forming, on an
average, about an inch in thickness; the whole is then firmly rammed (on
which, and properly preparing the facing stuff, the perfection of the work will
greatly depend,) until it is quite hard, when it will be compressed to about 1%
inch in thickness. The common facing stuff is composed of lime, one part,
and earth, the same as that used for walling, three parts. These are mixed
together, and slaked the same as mortar, and the more it is wetted and slaked
the better, provided time can be allowed for it to dry again and pulverize, so as
to be fit for ramming. The better sort of facing stuff may have a small quan-
tity more of lime in it. When by the repeated addition of layers of earth,
well rammed down, as before described, the mould is filled, the keys are to
be taken out of the bolts, and the bolts drawn out; the planks are then removed,
and put together again another length along the wall; but the bolts at one end
being put through the holes left in the wall, only one of the end boards is now
required; the earth is then thrown in and rammed as before, and the process
is continued until one course of all the walls is completed. When the lower
course is finished, the mould is taken to pieces and put together upon that
course, the lower bolts of the frame being put through the holes which the
upper bolts made in the wall at the first operation; but in order that the ver-
tical joints formed between each mould should not coincide in the several
courses, the end board is in the first set of the moulds for a new course, set at
the middle of the length of the moulds, so that the work shall form a break-
joint, as it is termed in brick-work, with the course below. Windows and doors
may be left in the walls by fixing the heads of the moulds, and carrying up
quoins to form the same ; in erecting which some bond timber should be laid
in coarse mortar, and rammed in with the earth; lintels may also be laid at the
proper height. This method is the cheapest where only one window or door of
a size is wanted; but if many are required, the readiest way would be to make
some rough frames of boards, of equal width to the thickness of the walls, and
place them in the situations of the windows and doors. When done, the earth
is rammed up to them, laying bond timber on the sides, and lintels over them.
In both cases the windows and door frames are to be put in their places, and
fastened to the bond timber after the walls are up. The bond timber, lintels,
and plates, should be kept as thin as possible in order to prevent any disagree-
ment between the earth and timber in the shrinking or drying of the same.
The bond timbers may be 4 inches by 13; floor or wall plates 6 inches by 2;
lintels about 4 inches thick. For common cottages, when the whole of the walls
are up and covered in, the holes should be stopped with very coarse mortar,
made the same as the facing stuff, but used wetter, and after standing some
time to become thoroughly dry, may be either lime washed or finished with
rough cast; but if it be required to make the finishing as perfect as possible,
the following is the best mode; viz. with water and a brush thoroughly wet and
soak the wall for two or three yards, in superficies, at a time; all which parts,
during the said wetting, should be worked about with a hand float until the face
be rubbed smooth and even, by which the facing composition will so wash up
as to become a pleasant regular colour, the face smooth and hard when dry,
and not liable to scale off as a coat of plastering would do. It should have
been mentioned before, that, as it frequently happens that the top of one course
becomes too dry to attach to the succeeding course, it is advisable that, as soon
as the frame is set for the succeeding course, a small quantity of thick grout,
composed of ; lime and ; earth, be poured on the top of each course imme-
diately before the first layer of earth is put in. A very small quantity is
sufficient, and will add much to the strength of the work by cementing the
courses well together at the joints. . The workman should also, with the corner
of his rammer, in ramming home to the upright joints, cut down a little of that
part of the wall up to which he works: this will make the upright joints key
together, and unite in a solid manner. The earth proper for this work should
be neither sand nor clay singly, but a mixture of both. Clay is very objec-
tionable, as is also chalk, or calcareous earth of any sort. Sand is also not
BUOYS. 279
proper, unless accompanied by some binding property; the bolder and coarser
the sort of earth the better. Wheii used, it should retain no more moisture
than just to make it adhere under the pressure of the thumb and finger. Where
the earth is not by itself proper, it may generally be rendered so by admixture
with either clay or with coarse sand, as the case may require. With respect to
the expense of this sort of walls, Mr. Salmon observes that, as labour is the
principal part of that expense, and as in some places labour is dearer than in
other, the best mode of estimating it at different places is from the quantity
that a man should do in a day, which he has found is 13 yard in the common
day's labour of ten hours. At Woburn he estimated the expense as under:—
Labour, to making facing composition, fitting in, and
ramming to a 16-inch wall, when the earth is at
hand, (labourers being at 1s. 10d. per day,) per g s, a
yard superficial . . . . . . . . . . . 0 2 2
Lime for facing composition, at 8d. per bushel 0 0 3
Lime and labour in facing the outside of wall . 0 0 3
Total, if finished and faced on one side only . 0 2 S
If faced and finished on both sides, add 0 0 8
Total expense for walls finished on both sides . . . 0 3 4
At the same place, the value of a yard of brickwork is more than ten shillings,
of walling only 14 inches thick, the bricks being forty-two shillings per 1000,
and lime eightpence per bushel; consequently the economy of pisé must
appear; and the same difference will be found in any other place where lime
and bricks bear the same price, and proper earth can be found at hand. But
it must not be concluded that the entire expense of a building will be in the
same proportion; the economy of pisé over brickwork applies only to the walls
of a building, the roof, floors, fittings, &c. will be nearly the same in both
cases, and even as regards the walls, the brickwork of the foundations must be
taken into the calculation.
BUOY. A floating mark to point out the position of objects beneath the
water, as shoals, anchors, &c.; also any light body used to support in the water
another body, whose specific gravity exceeds that of water, as the buoys used
to support the swivel rings of mooring chains, &c. The buoys used to mark
the position of shoals, and to point out the right channel, are generally large
and strong conical casks, made water tight, and are retained in their proper
situation by a rope from the apex, made fast to an anchor dropped in the
desired spot. These buoys are variously distinguished, either by their colour, or
numbers painted on them; also sometimes by small beacons rising from their upper
surface. All these buoys are under the superintendence of the Corporation of
the Trinity House. Ships' buoys are generally formed as double cones attached
at their bases, and are mostly composed of wood; but these being very liable
to sink by leakage, buoys made of plate iron have for some time past been
extensively used both in the royal and mercantile navy. They are attached by
ropes, termed buoy-ropes, to the anchor, care being taken that the length of the
buoy-rope exceeds the depth of water in which the ship is to anchor. Their
principal use is for weighing the anchor in cases where the cable has broken
or been let go.
BUOY (Life). A buoy intended to support persons who have fallen into
the water, until a boat can be dispatched to their assistance. The forms and
materials of which life buoys are composed are very numerous. The annexed
cut represents a very simple and effectual machine of this kind invented by
Mr. Scheffer. Fig. 1 is the machine inflated with air. It is made of skins,
without any seam, (by a process of which the inventor retains the secret,) and
is perfectly air and water tight; it is provided with an ingeniously contrived
stop-cock, which screws into the hole shown in the engraving, by means of
which the machine may be readily inflated by blowing with the mouth, and its
escape afterwards rendered impossible. The buoyancy of the machine is suffi
280 BUOYS.
cient to support two persons; so that a man equipped with one, even if totally
unacquainted with swimming, need not hesitate to proceed to the assistance of
a person struggling in the water; and it is put on in a moment, by merely
stepping into it, and passing it up to the chest, where it may be worn without
Fig. 1. Fig. 2.
ºilº
g ºf
!!! iſ
' ' , ; * *
| " ' " |
: Iſ -
| * *
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- b% *}
ºft|||
Vºl. º | - !II, t f º - iili
i. | | |||||||| | | | º #) § º l $º -.
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inconvenience, or in the least impeding the full action of the limbs. Fig. 2
represents another construction, by which the machine can be more easily put
on over the clothes. The following cut represents the air cock. a is the nozzle
'A' || º
ºlºlºlºl)|| | ||||||}|
** | | ºf:
of the cock, which is screwed into the elastic air vessel; b an ivory pipe screwed
into the barrel, used, when required, as a mouth-piece to inflate the vessel; when
that is effected, the handle d of the plug is turned, so that the hole e of the plug
is brought round opposite to the bolt f, when the spiral spring g projects the bolt
into e, and locks it fast. The hole e is perforated through the plug, so that the
locking takes place whether the plug be turned to the right or to the left: thus
the cock is secured from being opened by accident, and the escape of the air is
prevented. To open the air passage it is necessary to draw and hold back the
spring-bolt with one hand, while the other turns the handle d into the position
shown. Another important purpose to which these buoys may be applied is
that of floating a rope from a stranded ship, by which means a communication
with the shore is more easily established than when it is attempted to convey a
rope from the shore to the ship, as the wind and sea assist in the transmission
of the rope in the first case, whilst in the latter, they form a serious obstacle to
it. Spars and casks are sometimes employed to float the rope, but are much
inferior to the present invention, as the lives of the men passing along the
floating line are greatly endangered by their being struck with them. The
weight of such apparatus likewise keeps the floats deep in the water, con-
sequently less exposed to the action of the wind, so that the tide may carry the
rope in a wrong direction; but with Scheffer's buoyant vessels lying on the
surface of the sea, the wind would have so powerful an effect as to render the









BUOYS. 281
course of the tide immaterial; the passengers and crew might then with security
* * * * * * * * * -- - - -- - - - - * - l. .. _ ] . . - º - T * - * * ... v. -
Fºcuss ałońg the 1 Upe vv. the shore. a tile air vessel, or 11oat for the rope b,
sº J
sºsºsºssºss
* *
* T Twº" º
-- " - º' “º “Y- p-
which is suspended by the rings to the bands ec c.; d d the water line, or depth
at which it lies immersed when the rope is attached.
A most admirable life buoy, for the preservation of men who may have the
misfortune to fall overboard at sea, by day or night, has been invented by Lieut.
Cook, R.N. and is so much approved, that the lords of the Admiralty have given
orders that every ship in the royal navy shall be fitted with one. The buoy is so
fitted to the stern or quarter of the ship, that in the event of an accident by
night, it can be detached from its position into the water in about ten seconds,
with a fusee at the head of the staff, giving a brilliant light, which a sea passing
over it cannot extinguish. Ships may on these occasions frequently have to
run a mile before they can sufficiently shorten sail so as to heave to with safety;
but the buoy having fallen close to the man, the light blazing above his head will
direct the boat to the spot without loss of time: this is a most valuable feature
in the invention, invaluable, as from the great difficulty of finding a man in the
water in a dark night, under these circumstances, men have been left to perish
when there has been every reason to conclude that they had reached whatever
might have been thrown to their assistance. The apparatus consists of two
hollow copper spheres, connected together by a horizontal bar, through the
middle of which is fixed, vertically, a strong staff, formed of a metallic tube;
sº.
º º º
º ºis. §
º
šč. t ſºft li lil º
º gº. Fº
iº
it
§
3.
f
º ſº º #i
#ºs=º
Es S=Sº
Sºs
zº
the upper extremity of this tube supports the fusee, and the lower portion contains
the balance rod and weight, which drop out of the tube when the apparatus is
released from the ship, and preserves it upright in the water; the fusee is
lighted at the same instant by a gun lock. The above cut represents





282 BURNING GLASS.
the life buoy suspended at the stem of a vessel. In man ...ips, the communi-
cation with the triggers for firing and for letting it go, is so contrived, that the
man at the helm can detach it without quitting his post. The following cut
§
---
§
#
:===
š=#s
2:
represents the lifebuoy in use, with the fusee blazing over the head of the man,
who is seen standing on the balance plate.
BURNING GLASS and BURNING MIRRoR. Instruments for concentrating
upon a very small surface the rays of the sun, which fall upon a much more
extended one, by which means such an intense heat may be produced as to
fuse, burn, or volatilize most substances. Burning glasses are convex lenses,
which, acting according to the laws of refraction, transmit the rays, but
incline or refract them towards a common point in the axis, called the focus.
These were not entirely unknown to the ancients, although we have no minute
accounts of their construction or performances; but in modern times very
powerful instruments of this description have been constructed. The most
celebrated is that made by Mr. Parker, of Fleet-street, at an expense of 700l.,
and several years of labour and research. It consisted of a lens composed of
flint glass, which, when fixed in its frame, exposed a surface of 32 inches
diameter in the clear; the distance of the focus was 6 feet 8 inches, and its
diameter one inch. The rays from this large lens were received and transmitted
through a smaller one, of 13 inches diameter in the clear within the frame, its
focal length 29 inches, and the diameter of the focus of an inch. Amongst
other remarkable effects produced by this instrument were the following: 3
grains of cast iron were fused in ten seconds; 20 grains of gold in four seconds;
10 grains of steel in twelve seconds; and 10 grains of common limestone in
fifty-five seconds. Ten cut garnets, taken from a bracelet, began to run the one
into the other in a few seconds, and at length formed into one globular garnet.
The clay used by Mr. Wedgwood, to make his pyrometric test, run, in a few
seconds into a white enamel. We are sorry to add to the account of this

BUTTONS. 283
wonderful instrument, that, after being offered for sale to several learned
societies, we believe it was sent to China, either on speculation, or amongst the
presents which accompanied Lord Macartney's embassy, and was there left.
Burning mirrors are concave mirrors or reflectors, formed of polished metal or
silvered glass, and which, acting by the laws of reflection, throw the rays back
into a point or focus before the glass. These instruments were not only well
known to the ancients, but, if we may credit the accounts which have come
down to us, the effects of some of their contrivances were superior to any pro-
duced in modern times by the same means. Archimedes, it is said, reduced
the Roman fleet under Marcellus to ashes, by burning mirrors, at a bowshot
distance; and Proclus is said to have burned the fleet of Vitellius at the siege of
Byzantium by the same means. Of the moderns, the most remarkable burning
mirrors are those of M. de Villette, and of Buffon. That of M. de Villette was
3 feet 11 inches diameter, and its focal distance 3 feet 2 inches. It was com-
posed of tin, copper, and tin glass. Some of its effects, as found by Dr. Harris
and Dr. Desaguliers, are, that a silver sixpence melted in 74 minutes; a
halfpenny melted in 16 minutes, and ran in 34 minutes, and a diamond
weighing 4 grains lost ; of its weight. That of M. Buffon is a polyhedron,
6 feet broad, and as many high, consisting of 168 small mirrors, or flat pieces
of looking glass, each 6 inches square, by means of which, with the faint
rays of the sun, in the month of March, he set on fire boards of beech wood
at 150 feet distance. At another time he burned wood at 200 feet distance;
he also melted tin and lead at the distance of above 120 feet, and silver at
50 feet.
BUTTON. A fastening for various parts of dress. Buttons may be divided
into two general classes, those with shanks, or loops of metal, for the purpose
of attaching them to garments, and those without shanks; and each class is
manufactured from a great variety of materials, and by a variety of methods.
Of buttons with shanks the greater number are composed of metal, although
glass and mother of pearl are also employed for the purpose. Metal buttons
are formed in two different ways, the blanks or bases of the buttons being either
cast in a mould, or stamped out of a sheet of metal; the former method is
generally employed for making white metal buttons, and the latter for plated
and gilt buttons. To cast buttons, a great number of impressions of the pattern
of the button are taken in sand, and in the centre of each impression is
inserted a shank, the ends of which project a little above the surface of the
sand, and fused metal is poured over the mould. When cool, the buttons are
taken from the moulds, and after being cleansed from sand by brushing, are
placed in lathes, the edges are turned, the face and back smoothed, and the pro-
jecting part of the shank also turned. The buttons are then polished by rubbing
the faces upon a board spread with rotten stone of different degrees of fineness,
and afterwards by being held against a revolving board covered with leather,
upon which is spread a very fine powder of the same materials; finally, they are
arranged on a sieve or grating of wire, and immersed in a boiling solution of
granulated tin and cream of tartar, by which means their surfaces become
covered with a thin layer or wash of the metal, which improves their whiteness
without injuring their polish. The blanks of plated buttons are cut by a fly-press
out of copper plate, coated on one side with silver. They are then annealed
in a furnace, and afterwards stamped by the descent of a weight, as in a pile-
driving machine, the die being fixed in the lower surface of the weight. The sol-
dering of the shank is performed on each button separately, by the flame of a
lamp and a blow-pipe: the edges of plain buttons are next filed smooth in a lathe,
and the buttons are afterwards boiled in a solution of cream of tartar and silver;
they are then placed in a lathe, and the backs brushed, and afterwards burnished
with blood-stone. The metal used for gilt buttons is an alloy of º and zinc.
This metal is rolled out into sheets, and the blanks stamped out, which are then
planished if intended for plain buttons, but if for figured buttons, the impres-
sion is now given The shanks are next attached, which is effected as follows:
each blank is furnished with a pair of small spring tweezers, which hold the
shank down upon it on the proper place, and a small quantity of solder and
284 - BUTTONS.
resin is applied to each. They are then exposed upon an iron plate to a heat
sufficient to melt the solder, by which the shank becomes fixed to the button;
and whilst still warm they are plunged into nitric acid, to remove the oxide
formed on the surface by the heat employed in soldering the shanks. They are
then placed in a lathe, the edges rounded, and the surfaces rough burnished,
which renders them ready for gilding. Five grains of gold are fixed by Act
of Parliament as the least quantity to be employed in gilding a gross of buttons
of 1 inch in diameter. An amalgam is formed of gold and mercury, and the
buttons are placed in an earthen vessel along with the amalgam, together with
as much aquafortis as will moisten the whole, and the mixture is stirred with
a brush until the buttons are completely whitened. To dissipate the quicksilver
the buttons are shaken in an iron pan, placed over a fire, until the quicksilver
begins to melt, when they are thrown into a felt cap and stirred with a brush,
to spread the amalgam equally over their surfaces; after which, they are returned
to the pan, and the mercury volatilized completely by the increased heat, leaving
the gold evenly spread in a thin film over the surface of the buttons; they are
then burnished in a lathe, which completes the operation. The better sort of
buttons undergo the gilding process twice or thrice, and are distinguished
accordingly as “double" or “treble gilt.” Glass buttons are formed of glass
compressed, while in the fluid state, in moulds, in which the shank is inserted,
and when the glass becomes cold, the shank is firmly retained in its place. In
mother-of-pearl buttons the method of inserting the shank is extremely inge-
nious : a hole is drilled at the back and undercut, that is, larger at the bottom
than at top, and the shank being driven in by a steady stroke, its extremity
expands; on striking against the bottom of the hole, it becomes firmly rivetted
into the button, forming a kind of dove-tail joint.
Buttons without shanks are of two kinds; the first are simply discs of horn,
bone, wood, or other material, with four holes drilled through the face, for the
purpose of sewing them to the garment. Horn buttons of this description are
made from cow-hoofs by pressing them into heated moulds. The hoofs having
been boiled in water until they are soft, are first cut into plates of the requisite
thickness, and after into squares of the size of the diameter of the button, and
afterwards reduced to an octagonal form by cutting off the corners. They are
then dyed black by immersing them in a cauldron of logwood and copperas
mixed. A quantity of moulds somewhat resembling bullet moulds, and each
furnished with a number of steel dies, are then heated a little above the point
of boiling water, and one of the octagonal pieces of horn is placed between each
pair of dies, and the mould being shut is compressed in a small screw press,
and in a few minutes, the horn becoming softened by the heat, receives the
impression of the die, after which the edges are clipped off by shears, and then
rounded in a lathe. The holes in buttons of this description are drilled by
means of a lathe, represented in the annexed engraving. Four spindles, of which
two only a a can be seen, are supported in bearings at b, and by the centre
points c c are made to revolve with great velocity by means of two bands d d
passing over pulleys e e fixed upon each of the spindles, each band driving two
spindles, and receiving motion from a wheel worked by a treadle. At the end

BUTTONS. 285
of each of the spindles a, is a hook uniting them to four other spindles ff by
similar hooks at one end, the other eiid of the spindles passing through four
small holes in the plate g, and the projecting points being formed into small
drills. The button is placed in a concave rest h, and pushed forward against
the drills by a piece of wood. The standard g can be exchanged for another
with holes more or less apart, and the rest h can be set at any height to suit
different sized buttons. As the spindle holes in the plate g are nearer together
than the holes in the standard b, the spindles ff converge; the hooks in the
spindles are therefore necessary to form a universal joint. The second descrip-
tion of buttons without shanks consists of thin discs of wood or bone called
moulds, covered with silk, cloth, or other similar materials. The bone for the
moulds is made from refuse chips of bone sawn into thin flakes, and brought
into a circular form by two operations, illustrated by the accompanying
engraving. On one end of the spindle a, which revolves in bearings at b b, is
screwed a tool c, and on the other are two collars d d, between which a forked
lever e embraces the shaft, the fulcrum of which is at f. The spindle a is put
in rapid motion by a band g passing over the pulley h, and over a band wheel
worked by a treadle; and the workman, holding the material i for the mould in
his right hand, against a piece of wood k firmly held down in the iron standard 2
by two screws, by means of the lever held in his left hand, he advances the tool
c against the material i of the mould; the central pin of the tool drills a hole
through the centre of the intended mould, whilst the other two points describe
a deep circle cutting half through the thickness of the material, and the flat
surface is cut smooth by the intermediate parts of the tool. The tool is then
drawn back a little by the lever e, and the material shifted to bring a fresh
portion of the surface opposite the tool, and when as many moulds as the plate
of the material will afford, are thus half cut through, the other side is presented to
the tool, and the central point of it being inserted in the hole made in the first part
of the operation, the other two teeth cut another deep circle exactly opposite the
former one through the remaining substance of the material, and the mould is
left sticking on the tool; by drawing back the lever e the tool recedes, and the
mould, meeting a fixed iron plate, is pushed off the tool, and falls into a small box m.
Covered buttons having come into very general use, various improvements
have been introduced in the manufacture of them, and patents for this purpose
have been granted to various parties, as
Sanders, Needham, Aingworth, Church,
and others. The following is Mr. Sanders'
method of making covered buttons: a
piece of the material with which the mould
is to be covered is cut of a circular shape,
somewhat larger than the intended button;
upon this is placed a disc of card of the
exact size of the button, and next a disc of (3)
C, O
C
º
º:
º
paper coated with an adhesive composition, c
which will become soft and sticky by heat;
O O










286 CABLES,
and upon these is laid a button mould e having four holes, through which
threads or strings have been passed to form the flexible shank. These circular
discs being put together, are then laid over a cylindrical hole in a metal
block a ; this hole being exactly the size of the intended button, and the
covering of the button being larger than the hole, when the discs are pushed
down into the hole, the material of the covering will wrinkle up on the edges
round the other discs. The tube b b is then introduced into the cylindrical
hole, and its lower edge being bevilled inwards, will, as it is pressed down,
gather the plates of the cloth on the edge of the button; towards the centre
is a metal ring or collar c, having teeth round its edge; somewhat like a crown
saw is now passed down the tube b, and driven with considerable force by
the punch d, and the block a having been previously heated, the adhesive
matter will be softened, and cause the several discs to stick together, which,
when taken out and become cold, will be very firm and retain its shape.
C.
CABLE. A rope of large diameter, by which ships are held to their anchors
or moorings. The materials of which cables are formed are very various, as
bass, hemp, sunn, and coir, or the husk of the cocoa nut, and latterly iron
chains, of a particular construction, have been extensively used, and are com-
monly called chain cables. Cables are composed of either three or four ropes
twisted together, each rope consisting of either three or four strands, each strand
containing an equal number of yarns, which number depends upon the diameter
of the cable. Cables are denominated by their circumference in inches, as a
22-inch cable, meaning a cable 22 inches in circumference. The length of all
cables is the same, viz. 120 fathoms. The larger class of ships in the navy
and in the East India Company's service are usually provided with the following
cables: viz. two spliced together, for the best bower anchor; two for the small
bower anchor; two for the sheet; one spare cable; and one cable for the stream
anchor. The chains employed for cables have a short stay bar in the middle
of each link, to prevent the sides collapsing when the cable is exposed to a
heavy strain. The form of the links and stays, and the mode of applying the
latter, have formed the subjects of numerous patents. The annexed figures
represent one of the links of Mr. Hawks's “Patent Chains for Cables and
Hawsers,” and also illustrates the method of forming them. The novelty
A.
in the form of these links consists in their being thicker at the bends than at the
sides; whereas in most other chain cables the links are either the same thickness
throughout, or are smallest at the bends. The iron rod a a of which the link
i. formed, it will be seen has bulbous en-
argements at regular distances asunder: —
these are º either by cavities in the _T - N
rollers between which the rod is drawn, or ~
by swaging or forging. The rods being cut - | 3
into exact lengths, they are turned round \ { - *
into links, and the ends welded together,
when the bulbs should be situated exactly
at the ends, as represented by the annexed
figure at a a, and the stay-bar b inserted.
Chains for cables are commonly made in lengths of 10 fathoms, connected by
a bolt and shackle, for the convenience of slipping on in an emergency, as cutting
is of course out of the question; and at every 30 fathoms is a swivel, that the
chain may not become twisted. A simple and effectual stopper for chain cables
is much wanted, as considerable difficulty is frequently experienced in “bringing
a ship up,” as it is termed, when it blows hard. The ordinary stopper consists
of two concave plates of iron, between which the chain passes; the lower plate



COCOA. 287
3s gºal. saas-ca to the deck, and the upper plate turns upon a ls -- ~~ A ----.
4 tº *** ****) SCCRR ſcs. Lù via • *-** **** 3 ** = a \A vas" “fºr” + tº “v v Út A. J. M. 13 **E*val Cº. 111145°. …Tº. aving
iron bai is inserted into a socket cast upon the upper plate, and tº the outer
end of the bar is attached a tackle, hooked to a bolt in the deck; and a number
of men being stationed at the tackle, by hauling upon it they compress the
cable so tightly between the plates, as to prevent the cable running out, or,
by slacking it, allow it to run freely. This apparatus frequently gives, Way,
ańd occasions serious damage. The following substitute, invented by Lieut.
Kooystra, R.N., has been approved by the Society of Arts, who have presented
the inventor with the silver Vulcan medal. The figure represents an under-
view of the part of the deck where the stopper, a q is fixed; this stopper is
formed of an iron hook or clip, turning upon a bolt at b, and has a few links of
chain at the other end; d and e are portions of two beams; f part of the chain
&=ºutº.
47
cable, held fast by the stopper; g a square bar, sliding through the beam d, and
through square holes in the metal facing plates h h; i the hook in the end of
the barg, which takes the link j of the stopper; k a double-threaded screw, on
the other end of the bar g; l the screwed end of a crank handle m, fitted on
the screw k, the other end turns freely in the plate o 0, pp the bolts which
secure this plate to the beam e. By turning the crank one way, it will be seen
that the cable will be tightly pressed by the stopper against the iron knee q, and
by turning it the other way the pressure is relaxed. The sliding bar g is shown
separate above.
Mr. William Shelton Burnett had a patent for a cable-stopper, of which the
following is a description. This apparatus consists of a metallic box a, con-
taining a spirally coiled spring, through the centre of which passes longitudinally
~~- *~ - - -- ~~~~<^*—- —
a bar; one end of this is strongly rivetted to an iron plate, and the other ter-
minates in a large eye, for the reception of a hook or a rope. Now, supposing
the cylinder a to be made fast at b to some staple part of a ship, and the cable
c, which passes over the side of a ship d, tº have an anchor attached to the other
extremity, when any strain comes upon it, the bar is drawn more or less out of
the cylinder, compressing the spring, thus affording an elastic resistance, which,
continually increasing with the force applied, will prevent those accidents of
tearing away the fastenings, which might, without such apparatus, be the result.
It is of course that this contrivance is equally applicable to any other tackle,
which it will always keep in a proper state of tension after the cause of the
adventitious strain has ceased to operate.
CACAO NUT, or Coco A. An oblong roundish nut, nearly the shape of an
almond, but larger; the shell dark-coloured, brittle, and thin; the kernel both
externally and internally brownish. ... It is the produce of a small tree, the
Obrama Cacao, bearing a large fruit like a cucumber, which contains thirty ºr



288 CAISSON.
more of these nuts Chocolate is prepared from these nuts. A patent was
lately obtained for a preparation of cocoa, called “Marshall's Extract of Cocoa.”
The specification, which is dated the 10th February, 1830, describes the process
to consist in boiling, for an hour, a pound of powdered cocoa in a gallon of
water; the mixture is then to be passed through a sieve, and the oily matter to
be skimmed from the surface. It is next to be evaporated in a water bath, till
it assumes the consistence of treacle, when it is to be preserved for use in
bottles well corked and sealed, so as to render them impervious to the air.
CAISSON. A kind of chest-framed or flat-bottomed boat, sometimes used
in laying the piers of bridges in deep or rapid rivers. The caissons for this
purpose consist of a very strong platform of timber, to which are attached the
two sides, in such a manner as to admit of their removal when no longer
required. These sides, which are also very strongly framed of timber, to resist
the great pressure of the water, are curved towards their extremities, so as to
meet each other, and form a salient angle up and -
down the stream, and inclosing a space somewhat
wider than the foundation of the pier of the
bridge. The site of the pier being levelled by
dredging or otherwise, the caisson is brought
over the spot, and moored in the proper
position; two or three of the lower courses of
masonry are then built upon the platform of
the caisson, and the water is then slowly ad-
mitted by a sluice in the caisson, so as to cause
the caisson to settle into its place; and to prevent
the effects of too great a pressure of water when
the rise and fall of the tide is considerable, the
water is generally admitted some time before high
water, and pumped out again after the ebb tide
has commenced, so that the workmen may resume
their labours before low water. When themasonry I. 3.
is brought up as high as the level of the water,
the sides of the caisson are detached from the
bottom, and removed. Westminster and Black-
friars bridges were built on caissons, but the
preference is now generally given to coffer dams.
A patent was obtained by Mr. Deeble, for con-
structing jetties, piers, quays, &c. by means of
what he terms “metallic caissons,” or a peculiar
description of cast iron boxes, variously combined
by dovetails; these boxes, when fixed in their
i. to form a pier, or quay, &c. are filled with
iquid lime and rubble, which soon sets hard, and
forms a solid mass girt with metal. For the
better elucidation of the plan, a few of the more
simple forms of caissons, and their mode of
uniting, as exemplified in the construction of a
pier, are engraved here with. The caisson is open
generally both at top and bottom; the thickness
of the sides proportioned to the strength and
gravity required. It is proposed that each caisson
be 7 feet in length, 5 feet in height, and from 2
to 5 feet in width, according to the nature of
the work in which it is to be used. Caissons
constituting foundations should be closed at
bottom, and in raising one tier above another, each layer would become united
to those immediately above and below it, by commencing the alternate vertical
courses with a half caisson. Fig. 1 is the plain oblong square, with dovetails at
the ends, only applicable to straightlines, either in banking exposed to the water,
or to the interior of heavy works, as cross forts, or in bracings and buttresses to be


CALCULATING MACHINES, 289
buried in the earth. This form admits but little variation in its application,
and none in its strength or gravity beyond what may be gained by increasing
the thickness of its sides. Fig. 2 is the most universal form; it may be muj.
tiplied to any extent, yet is perfect in itself, requiring no change of form on
the side to finish a work, and the ends may be conveniently completed by
filling up the dovetail groove with a portable half dovetail. Fig. 3 is the
radiated form, which may be used in a waved line along the coast, where great
strength is required; it also applies to piers and bastions. The dotted projection
is the half dovetail, which would be required to attach it to the cross fort; or
the radiated caisson, should it be considered necessary to add another waved
line, would give the effect of arch and counterarch. Fig. 4 is a radiated caisson,
having extra dovetails for uniting the main line to the bastion. Any angle may
thus be gained, simply by mooring this caisson in the bastion, in the direction
required. Fig. 5 is the termination of a pier with a bastion: the external dotted
Fig. 5.
* * * * * * - - - - - - - - - - - -
t - -> - • *
ºfflic
WN
§§ º § ... " §§ *
§ § sº N § º º
Nº. t N & § N º i N N Yº s
§ º § - § § º § N § § \\ ;
N NNN . § Nº. §§ ºRN § º § ;
Wººlºº. ºº: Tºº ...'
* §§§ YN
"As W
*
Y - - - - - - *
* *
*** - - - - - - - - *
º
& º
Lº's Ny
* * * * * * * * * * * * * * * - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - * ~
e
*
*
line shows the boundary of the sloped bank; the cross forts are introduced at
suitable distances to insure great stability; and the inner dovetailed grooves
being left in the inner lines, will enable the engineer to add cross forts and
buttresses to any extent that may be required.
CALAMINE. An ore of zinc, principally used in making brass.
CALCINATION. The process by which some bodies are rendered reducible
to powder; it consists in exposing the substances to a strong heat, so as to dissi-
pate the water of crystallization and other volatile portions.
CALCULATING MACHINES. Machines devised for facilitating arith-
metical computations. From a remote period of antiquity, various mechanical
devices were resorted to for this purpose. Amongst the Greeks and Romans,
an instrument called “abacus” was employed, consisting of a number of
parallel threads, upon which were strung a number of beads for counters, to
represent units, tens, hundreds, &c. The Chinese at the present day use in
their computations an instrument called a swanpan, nearly resembling the
Greek abacus, and which may now be met with in the toy-shops of London.
There are large and small swanpans; those for mercantile purposes consist of
many rows of small balls strung on wires, containing fifteen balls on each, with
space for their being moved up and down with ease. These rows of balls are
divided by a cross bar of wood extending from side to side, leaving five balls
above and ten below. Each ball of the upper row is of the value of the ten
balls on the lower row, and by moving down to the bar one of the upper balls,
the ten lower balls which had been moved up to the bar, are at liberty to repre-
sent any further sum until they have all again reached the bar, when a second
ball is brought down from the upper row, and so on until the five balls are
engaged, when their value is represented by one ball on the adjoining wire on
the left hand, and so on to any amount. These instruments are universally
employed throughout China for the purposes of computation; and so expert
are the Chinese in the use of them, that few Europeans, with the assistance of
pen and ink, can keep pace with them. The celebrated Napier, the inventor of


































290 CALCULATING MACHINES.
logarithms, contrived an instrument by which the operation of multiplication is
much facilitated, the product of any single figure with the multiplicand being
represented at once by a very simple mechanical operation. This instrument,
which consisted of a number of detached rods, each bearing at the top some one
unit with the products of the same, multiplied by the nine units ranged in a
line beneath it, is commonly known by the name of Napier's rods or bones. But
by far the most useful contrivance of this kind is the Gunter's scale, so named
after the inventor, Mr. Edmund Gunter, an eminent English mathematician,
who likewise was the author of several other very useful inventions. In the extent
to which the Gunter's scale has been adopted, it rivals the Chinese swanpan,
whilst its powers far exceed those of the latter instrument. It consists of a flat
ruler of box wood, 2 feet long, having various lines laid down upon it, by means
of which all the various problems relating to arithmetical trigonometry, and their
depending sciences, may be performed by the extent of the compasses only.
This will be best explained by a description of the line, called the line of
number, or Gunter's line, which is adapted to the solution of arithmetical
questions, and exhibiting a few practical examples. The line of numbers is
the logarithmic scale of proportionals, which, being graduated upon the ruler,
serves to solve problems in the same manner as logarithms do arithmetically.
It is usually divided into 100 parts, every tenth of which is numbered, beginning
with 1 and ending with 10; so that if the first great division stand for the
# of an integer, the next great division will stand for , and the intermediate
divisions will represent hundredths of an integer, whilst the large divisions beyond
10 will represent units; and if the first set of large divisions represent units,
the subdivisions will represent tenths, whilst the second set of large divisions
will represent tens, and the subdivisions units, and so on. The general rule for
using this instrument is as follows: since all questions are reducible to propor-
tions, if the compasses be extended from the first term to the third, the same
extent will reach from the second to the fourth term. The following are a few
examples of some of the uses of this line. 1. To find the product of any two
numbers, as 4 and 8: extend the compasses from 1 to the multiplier 4, and the
same extent applied the same way from 8, the multiplicand will reach the
product 32. 2. To divide one number by another, as 36 by 4: extend the
compasses from 4 to 1, and the same extent will reach from 9 to 36. 3. To
find a fourth proportional to three given numbers, as 6, 8, 9: extend the com-
passes from 6 to 8, and this extent laid the same way from 9, will reach 12, the
fourth proportional required. 4. To extract the square root of a number, say
25: bisect the distance between 1 on the scale and the point representing 25,
then half this set off from 1 will give the point 5 = the root required. In the
same manner the cube root, or the root of any higher power, may be found by
dividing the distance on the line between 1 and the given number, into as many
equal parts as the index of the power expresses, then one of those parts set
from 1, will extend to the number representing the root required. A great
improvement has been made in this instrument, by means of which compasses
are rendered unnecessary. It consists in having two lines of numbers placed
one over the other, one of which lines is engraved upon a slider moving in a
groove, and is applied as follows: the first term of the proportional upon the
slider being set against the third term upon the fixed scale, the second term of
the proportion upon the slider will stand opposite the fourth term on the fixed
scale. Instruments of this description, with scales suited to almost every
branch of art in which calculation is required, are now common amongst in-
telligent workmen, and the scale of chemical equivalents, by which the labours
of the chemist are so much facilitated, is constructed upon the same principle.
Mr. Lamb has recently arranged the logarithmic scale in a circular form, by
which the portability of the instrument, and the facility of its application, is so
much increased, that an instrument much smaller than the following represen-
tation of it, and which can be conveniently carried in the waistcoat pocket,
contains divisions larger and easier to read than those usually placed on the
2-feet sliding rule. On the face of the instrument (which Mr. Lamb calls a
circular proportioner,) are engraved one double and two single logarithmic
CALCUTLATING MACHINES. 291
lines in concentric circles. The middle circle, which is the moving piece, and
is marked A, has both edges divided, for the convenience of acting with the
inner or outer circles, which are marked M and L. The moving and inner
circles A and M are both numbered 1, 2, 3, 4, 5, 6, 7, 8, and 9. The Space
betwixt each numbered division is divided into 10, and those divisions read
for a second figure. From 1 to 2 each of those divisions is subdivided into 5,
standing for the even numbers in the third places of figures. From 2 to 5
each tenth division is halved for the 5, in the third place of figures. The spaces
must be subdivided by estimation for the intermediate figures. The outer
circle, marked L, has a double line of numbers; the first half circle numbered
1, 2, 3, 4, 5, 6, 7, 8, 9, and the second half marked 10, 20, 30, 40, 50, 60, 70,
80, 90. The figures on A and M may either signify 1, 2, 3, &c., or 10, 20, 30,
&c., or 100, 200, 300, &c., and as the figured divisions alter, so, of course,
must the subdivisions; sometimes they stand for decimals. In passing unity
to the right, the numbers will contain a figure more, and in passing to the
left they will contain a figure less; the first significant figure in a decimal
will vary in like manner. Two numbers in a proportion which have the same
name must always be taken on the same circle. For multiplication, division,
and common proportion, A must work with M ; for the square root and dupli-
cate proportion, A must work with L. In direct proportion, the first and second
terms will stand together; but in indirect proportion, the second and third terms
will stand together.
Various machines have likewise been contrived by Pascal and others, by
which arithmetical calculations were made by means of trains of wheels and

292 CALENDERING.
similar arrangements; and the late Earl Stanhope invented a machine of this
sort, by which he verified his calculations respecting the national debt. But
none of these contrivances can bear a moment's comparison with the stupendous
machine designed by Mr. Babbage, and now nearly completed, the functions of
which are to embody in machinery the method of differences, which has never
before been done. It consists of two parts, a calculating, and a printing part,
both of which are necessary to the fulfilment of the inventor's views; for the
whole advantages would be lost if the computations made by the machine were
copied by human hands, and transferred to type by the common process. The
greater part of the calculating machinery, of which the drawings alone cover
400 square feet of surface, is already constructed, but less progress has been
made in the printing part. The practical object of this machine is to compute
and print a great variety and extent of astronomical and navigation tables,
which could not otherwise be done but at an enormous expense, whilst it would
be impossible to insure the same accuracy. It can also compute the powers and
products of numbers, and integrate innumerable equations of finite differences;
that is, when the equation of differences is given, the engine, after being properly
set, will produce in a given time any distant term which may be required, or
any succession of terms commencing at a distant point. In order to convey
some idea of the powers of the machine, we may mention the effects produced
by a small trial engine, constructed by the inventor, and by which he computed
the following table from the formula a”-- a +41. The figures, as they were
calculated by the machine, were not exhibited to the eye as in sliding rules
and similar instruments, but were actually presented to it on two opposite sides
of the machine, the number 383, for example, appearing in figures before the
person employed in copying. The table is as follows:
41 131 383 797 1373
43 151 42] 853 1447
47 173 461 911 1523
53 197 583 971 1601
61 223 547 1033 1681
71 251 593 1097 1763
83 281 641 1163 1847
97 313 691 1231 1933
1 13 347 743 1301 2021
Whilst the machine was occupied in calculating this table, a friend of the
inventor undertook to write down the numbers as they appeared. At first he
rather more than kept pace with the machine; but as soon as five figures
appeared, the machine was at least equal in speed to the writer. At another
trial, 32 numbers of the same table, containing 82 figures, were computed in
2 minutes 30 seconds, or 33 figures per minute. On a subsequent occasion it
produced 44 figures per minute, and this rate of computation could be main-
tained for any length of time.
CALENDERING. The operation by which all accidental wrinkles and
creases are removed from various kinds of cloths, and their surfaces rendered
smooth and uniform previous to packing for transport: calicoes are likewise
calendered before printing. The common calendering machine nearly resembles
the ordinary mangle, but worked by a horse-wheel, on account of its greater
dimensions and weight; but the more improved machines consist of a series of
rollers, between which the cloth passes, the rollers being subjected to heavy
pressure, and turning simultaneously either by simple contact, or by means of
wheel work, Machines on this principle we believe are of foreign invention,
but have received two important improvements in this country; first, by the
introduction of tubular cast iron rollers, into which heaters can be inserted when
requisite, which greatly assists the operation with some kind of goods; and
secondly, in the substitution of rollers formed of pasteboard for wooden rollers,
the former not being liable to crack or warp like the latter, and being susceptible
also of an astonishing degree of polish. These paper or pasteboard rollers are
formed as follows: the axis or shaft is formed of a square bar of wrought in on,
CALENDERING. 293
turned cylindrical at the bearings; a circular iron plate, of the exact size of the
intended roller, is placed upon the square part of the shaft, and near to the
end, and a great number of discs of pasteboard, somewhat larger than the
intended roller, and having square holes in the centre, are next put upon the
shaft, and then another iron plate, and the whole are screwed together by nuts
at the ends of four long iron bolts extending from one iron plate to the other.
In this manner a cylinder is formed, considerably longer than the intended
cylinder; this is removed to a stove or hot room, and as the paper shrinks by
the heat, the plates are gradually screwed up. When, at the end of some days,
the paper ceases to shrink, the cylinder is removed from the stove, and becoming
exposed to the humidity of the atmosphere, it has a tendency to expand, and
becomes exceedingly dense and solid, and is completed by turning in a lathe
to the intended size. Some goods are required to have a high polish, called glazing,
upon one side; this glazing was formerly effected by rubbing the cloth with a
smooth flint stone, but is now generally performed in the calendering machine, by
an addition of wheels, which causes one of the rollers to move slower than the
rest, and the cloth consequently rubbing over the polished surface of the
* @
-ſty
(I, | ||
d
b ||
C J
*T ||
Q, 1 ||
J
slowest mover, becomes glazed. a a Fig. 1, are two paper rollers, each of 20 inches
diameter; b b two hollow cast iron cylinders, 8 inches diameter, and 2 inches
thick, the exteriors of which are turned perfectly smooth; c a paper roller,
14 inches diameter; d d the framing of cast iron, containing the bushes or
bearings, in which the journals of the rollers revolve; these are firmly pressed
together whilst the cloth is passing through, by means of weighted levers.
Fig. 2 is an end view of the same calender, with the wheels for glazing the
cloth; the wheel on the upper cylinder b is 10 inches diameter, that on the
under cylinder b is 13 inches diameter, and both are connected by the wheel f;
so that the wheel on the under cylinder being nearly one-third more in diameter
than that on the upper cylinder, the difference of their motions retards the
P P

294 CALICO PRINTING.
centre paper roller, by which means the upper cylinder passes over the cloth
one-third quicker than the cloth passes through the calender, and polishes it in
consequence. For dressing muslins, gauzes, and other light, transparent fabrics
a smaller species of calender is employed. It consists of only three cylinders,
of equal diameters, (generally about 6 inches,) and is easily moved by a common
winch or handle. The middle cylinder is of iron; they are all moved with
equal velocities by small wheels. This machine is always used in a cold state.
Calendering forms one part of the business of a packer; in the subsequent
stages the goods are folded into certain forms, depending upon the nature of
them, and the markets for which they are intended; they are then subjected to
the action of a very powerful press, and whilst under pressure are corded,
so that when removed from the press they occupy much less room than they
otherwise would do.
CALICO PRINTING. The art of producing upon calico or cotton cloths
patterns or designs combining a variety of colours, so as to produce an agreeable
and pleasing effect. This ingenious business, as at present conducted, may be
considered as one branch of the art of dyeing; and as it depends chiefly upon
the proper application of a few compounds, called mordants, we shall commence
our description of the process by explaining briefly the nature of colours, and
the uses of mordants. The colouring substances employed in this art may be
divided into two classes, viz. substantive and adjective. A substantive colour is
one which of itself is capable of producing a permanent dye; such are woad
arrd indigo, and the solutions of some metals, particularly those of iron, cobalt,
gold, platinum, and silver, which give various colours, according to the processes
by which they are prepared. By adjective colours are meant all those which
are incapable of imparting permanent colours without the aid of certain inter-
media, which having a greater affinity both for the colouring matter and for the
cloth, than the colouring matter has for the cloth, forms, as it were, a bond of
union between the two latter substances. These intermedia are called mordants :
the principal ones at present in use in this country are the acetate of iron, the
acetate of alumina, and the various solutions of tin. In the usual process of
dyeing with adjective colours, the entire piece of cloth is steeped in the mordant,
and some time afterwards is submitted to a bath of the particular kind of
colouring matter which is to be imparted to it; but in printed goods, certain
parts require to be left white, a pattern, therefore, of those parts which are to
be coloured is cut in relief on blocks of wood, or plates of metal, and the
mordant being applied over the whole surface of the pattern, the pattern is then
impressed upon the cloth, and when the cloth is subsequently passed through
the colouring bath, only those parts to which the mordant has been applied
will receive a permanent stain; for although the whole piece will be coloured,
those parts which are untouched by the mordant will be easily restored to their
original whiteness by washing and exposure to the air. Previous to printing,
the cloth undergoes a variety of processes, termed the preparation. The first
of these is termed dressing, and consists in passing the cloth very rapidly over
a cylinder of iron, at nearly a white heat, or over a broad flame of gas. It is
next steeped for twenty-four hours in a weak alkaline lye, at the temperature of
about 1009, and is afterwards boiled in a solution of potash, which is called
ashing, and is then well washed, to free it entirely of the alkali. The next
process is called souring, which consists in immersing the cloth in water con-
taining about one-twentyfifth part of its weight of sulphuric acid, and being again
well washed and dried, the preparation is completed. Previous to the ordinary
description of printing, the goods are calendered, which consists in passing
them through a set of rollers, which gives them a gloss; but for what is termed
copper-plate printing, or cylinder work, the calendering is omitted. In printing
fast colours, the printer proceeds as follows: he lays the calico, which has
been already smoothed by calendering, upon a strong thick table, covered with
a woollen cloth, and proceeds to apply one or more mordants, as the case may
require, for fixing the intended colours. The mordants are applied by means
of wooden blocks, to the surface of which the pattern, cut oat of thick plates
of brass or copper, is firmly fixed. When the mordant is ready, it is either
CALICO PRINTING. 295
mixed with flour paste, or a thick aqueous solution of gum Arabic, gum Senegal,
gum tragacanth, or of what is called British gum, which is merely common
starch calcined and pulverized. In this state the mordant is spread upon a
piece of fine woollen cloth, strained tight upon a broad hoop. This is called
the sieve, and is placed within another hoop, called the case, covered with sheep
skin, or oil cloth, and the sieve within its case is placed in a tub of gum water,
and is ready for use. . The mordant is applied to the surface of the sieve by
means of a brush, which is called teezing; and should the mordant be colourless,
as, for instance, the acetate of alumina, some fugitive dye is mixed with it, to
make the pattern obvious to the workman, who, taking the block containing the
pattern in one hand, applies it gently to the surface of the sieve, so that a
sufficient quantity of the thickened mordant may adhere to the figures. He
then applies the block thus charged to the calico, giving it a blow with a small
mallet, and continues applying the block alternately to the sieve and to the
calico, until he has gone over the whole piece. When the piece is intended to
contain a variety of colour, several different mordants are thus applied, as the dif-
ferent colours require different mordants to fix them and render them permanent.
The calico is now removed to a room heated by flues, in order to be dried ; but
this is much better effected by an apparatus shown in the annexed engraving,
and consisting of a series of cylinders a a made of copper or tinned iron, and

2
| () ()(3) (º) G.) (3)
| |-TA / S * \| A \| Al-
d J C ſººscillo O__ bºrº CN, e
#== / r E
#E; 6 > º: N / 5 Ns g-->
F-v | | º | E---- T] I f
filled with steam, and round which the calico is made to pass in succession.
Beneath every two cylinders is a vane b b moved by a steam engine, which
agitates the air, so as very much to facilitate the drying; indeed, so rapidly are
the goods dried by this mode, that although the fabrics be wound from the heap
c on to the first cylinder perfectly wet, they become thoroughly dry by the time
they have passed over the whole apparatus, and fall in a perfect state on the
heap d. After drying, the pieces are passed by means of a winch through
water at various temperatures, with a little cow-dung mixed with it, in order to
remove that portion of the mordant which is not actually combined with the
cloth, and which might otherwise stain the white or unprinted parts. The pieces
are then taken to the river or wash-wheels, to be more effectually cleansed, and
afterwards passed through tepid water, in order to insure every impurity being
removed. A quantity of madder is next broken into a copper boiler of pure
cold water, and a fire is lighted beneath. The ends of several pieces of calico
are then skewered together, and immersed in the madder bath, and are kept in
constant motion by an apparatus (shown in the article DYEING), driven by a
steam engine until the whole attains the boiling temperature, or even for some
time after : the colour being by this means uniformly distributed, the pieces are
taken out and thoroughly washed. This process, which is called maddering,
has the effect of imparting all the requisite colours at one operation, which may
be thus explained: while one mordant precipitates the colouring matter to a
red, another precipitates a different portion of it of a purple colour; another
precipitates it black, and so of every possible shade from a lilac to a black, and
from a pink to a deep red. If a portion of weld or quercitron bark be added
to the madder, every shade from an orange to a brown may be produced;
whereas, if weld or bark alone be employed, all colours between a dark olive
and a bright lemon can be imparted to the cloth. The mordants generally used
in calico printing are acetate of iron for browns, blacks, lilacs, &c., and acetate
of alumina for all the different shades of reds and yellows When the goods
296 CALICO PRINTING.
have passed through the madder or weld copper, they are usually carried to
boiler containing wheat bran and water, for the purpose of freeing the white
grounds from the stain which they always acquire from the madder, bark, or
weld, employed in dyeing the print. It, however, frequently is the case that
goods will not bear to be sufficiently branned to clear the whites by that one
operation, as branning in some measure impairs the intensity of the colours;
such goods, therefore, are partially cleansed in the branning copper, and are then
either laid on the grass for some days, until they become perfectly clean and
white, or (which is a much more expeditious process) they are immersed for a
short time in a very weak solution of one of the bleaching salts, as oxy-muriate
of potash, soda, magnesia, &c. There is another method of calico printing
styled resist work, which is the reverse of that just described, the pattern being
printed on a cloth with a certain preparation which resists the colour, when the
goods are immersed in the dye vat, so that the grounds only are dyed, the
pattern remaining white. This process is practised for printing goods in which
the grounds are intended to be blue instead of white. To comprehend the
principles of this process, it should be understood that indigo, in its natural or
oxygenized state, has no affinity for cloth, but that it is deprived of its oxygen
by iron, which has a greater affinity for oxygen than indigo has, and the
deoxygenized indigo becomes soluble, and is readily fixed on the cloth. Copper, on
the contrary, has a less affinity for oxygen than indigo has ; the oxides of copper,
therefore, when dissolved, give up their oxygen to indigo in solution, which thus
acquiring oxygen, is restored to its natural state, and can no longer impart its
colour to the cloth. The process of resist work is conducted in the following
manner: a solution of some of the salts of copper, as the sulphate, nitrate,
muriate, or acetate, is thickened with flour paste and gum, or with pipe-clay
and gum; and with this composition applied to the blocks which contain the
pattern, the pieces are printed in the manner before described of printing
with mordants. The pieces, when thoroughly dried, are then repeatedly dipped
in the blue vat, as it is called, which is formed by mixing indigo with lime and
sulphate of iron, in such proportions as shall most effectually deoxidize the
indigo. In this vat the grounds receive the required depth of colour, but the
parts printed with the solution of copper remain undyed, because the deoxidized
indigo becomes oxygenated the moment it touches the copper, which parts with
its oxygen to the indigo, and occasions it to become insoluble, and consequently
incapable of forming a dye. After the goods have been sufficiently immersed
in the blue vat, they are washed and passed through diluted sulphuric acid,
when those parts which had been printed with the preparation of copper are
found to be preserved of a good white, the preparation having effectually resisted
the operation of the indigo, although all the other parts of the cloth have
received a permanent dye. When the pattern contains a variety of colours,
the white parts are subsequently printed by the method already described, (of
mordants,) and a bath of madder, weld, or quercitron bark, as the case may be.
Resist work, as we have already stated, is employed when blue is to be the
predominant colour or ground of the piece; but if the ground is to be white,
and the pieces to have only a small object in indigo blue, the colour is printed
with indigo deoxidized by orpiment, and commonly called pencil blue, because
formerly whatever objects were done with it, were put in with a pencil. This
preparation requires to be fixed on the calico before the indigo has time to
recover its oxygen from the atmosphere; to protect it from which an apparatus
has been contrived, in which the sieve which furnishes the colour to the blocks
floats within the colour contained in a vessel, in which the liquid is supplied
from an air-tight reservoir, on the principle of a bird fountain, so as always to
maintain the liquid in which the sieve floats at the same height. A third
method of printing calicoes is that called discharge work, which consists in first
dyeing the cloth of some uniform colour, by means of some of the common
vegetable dyes, and iron liquor, which is always used in such quantity as to
cover, or at least to disguise in a great measure, the colours employed with it.
The cloth is then washed, dried, and calendered, and then printed with a solution
of one or more of the metals in some of the mineral acids, which, dissolving the
CALICO PRINTING. 297
Ton in the parts to which the pattern is applied, restores the cloth to the colour
with which it was originally dyed. i hus, if a piece, treated with a decoction
of Brazil wood, and dyed black by being passed through iron liquor, be afterwards
printed with a peculiar solution of tin, the ferruginous part of the dye will be
dissolved, and the printed part will instantly be converted from a deep black to
a brilliant crimson. This process is only applicable where all the purposes are
attained by simply dissolving the iron which forms part of the colour that is to be
discharged; whereas, for the fine and more expensive work, citric acid, mixed
with gum or flour paste, is printed on the cloth, and wherever it attaches, the
mordant, whether iron or alumine, is discharged, and a delicate white is left in its
place. There is another species of discharge work by which the patterns on
the beautiful Turkey red bandannas are produced; but as this cannot be pro-
perly called a printing process, we refer our reader for a description of it to the
article BANDANNA. The ordinary sorts of what is called chintz furniture are
produced by the process first described, which is repeated one or more times
for the superior sorts, varying each time the mordants and the dyeing stuffs;
and when the greatest possible variety of colouring is desired, a portion of the
white ground is sometimes coloured blue, by putting in with a pencil the pre-
paration called pencil blue; and green is in the same manner produced by
applying some of the same colour to parts previously dyed yellow. We shall
conclude this article by noticing an improvement which has been made of late
years by the introduction of cylinder printing, which has the advantages of
Superior accuracy and neatness, as well as of greater expedition. In these
r I | *I
printing machines the pattern is engraved on cylinders of . or brass, or
wood, which supply themselves with the prepared colour during their revolutions,
which colour is transferred to the cloth by the latter rolling over the printing
cylinder as it is wound from one roller on to another. Many of these machines

298 CAMERA LUCIDA.
are contrived so as to carry two of these cylinders, each of which has a trough
of colour attached to it, by which means two different colours may be printed
at a time on one piece of calico, and Mr. A. Parkinson, of Manchester, has
invented a machine capable of printing at one time, by means of one cylinder
and two surface rollers, or by two of the former and one of the latter, three
distinct colours. The leading arrangements of this machine are exhibited in the
engraving on the preceding page. a the main roller of iron, round which the calico
passes to receive the impression from the three smaller rollers; b one of the
screws, to give proper pressure to the main roller; c a copper roller, with one
of the patterns engraved on it, and pressed against the main roller by the screw
d. The roller c receives colour from a small box at the top, which could not be
shown in the engraving, e and e two wooden rollers, on each of which is cut
a pattern ; fiftwo blankets, to supply colour to the rollers e e. These blankets
receive the colour by revolving in contact with the rollers g g, turning in the
colour boxes h h, and the colour is uniformly spread by the rotatory motion, by
the time it arrives at the rollers on which it is to be deposited. i i are guiding
and stretching rollers to the two colour blankets; k the guide roller to the
blanket which is interposed between the main cylinder and the calico; l the
roller from which the plain calico is unwound during the process of printing;
m the calico passing from the printing rollers in a printed state. Mr. Parkes
(from whose Essay on Calico º: foregoing description of the process
is taken,) observes, that not only is the printing more correctly performed by
the cylinders than can possibly be done by means of the block, but also the
saving of time and labour is so great, that a piece of calico which would take
a man and a boy three hours to print with one colour, or six hours to finish with
two colours, may be printed by the machines in three minutes, or three minutes
and a half, and the work will be much more completely done than could have
been even imagined before the introduction of this invention.
CALLIPERS. A sort of compasses, made with bowed or arched legs, and
used for measuring the diameter of cylindrical bodies.
CALOMEL. Chloride of mercury, frequently called mild muriate of mercury.
CALORIC. A modern term to denote heat, or the cause by which the
phenomena of heat are produced. . See CHEMISTRY.
CAMBER. A term applied to that slight degree of arching which is usually
given to beams, which see. e
CAMEL. A contrivance for lifting ships over a bar or bank obstructing the
navigation of a river. It is used in Holland, and some other parts, particularly
at the Dock at St. Petersburgh. A camel is composed of two separate parts,
whose outside is perpendicular, and the inside concave, so as to embrace the
hull of a ship on both sides. They are braced to a ship underneath, by means
of cables, and entirely enclose its sides and bottom. They are then towed to
the bar, and the water being pumped out of them, the camel rises, liſts up the
vessel, and the whole is towed over the bar.
CAMEO. The name given to stones of various colours, which contain
ancient sculptures in relief.
CAMERA LUCIDA. An ingenibus and elegant invention of the late
Dr. Wollaston, for the purpose of facilitating the delineation of objects, by
producing a reflected picture of them upon the paper. It consists of a solid
prismatic piece of glass, mounted upon a stem capable of elongation or con-
traction, and which can be screwed at the foot to a table or drawing board. The
prism has its angles so arranged, that the rays from the object are reflected upon
the paper, and is covered at top by a metallic eye-piece, the hole in which lies
half over the edge of the prism, so as to afford to a person looking through,
a view of the picture reflected through the glass, and a direct view of his pencil
or tracing point. By means of this instrument, a person unacquainted with
drawing may delineate objects with great ease and accuracy. For specimens
of the capabilities of this instrument, we would refer to the volume of plates to
Capt. Basil Hall's Voyage to the United States of America, the whole of which,
consisting of representations of scenery, animals, portraits, &c. were sketched
by means of this instrument by Capt. Hall, who had no knowledge of drawing.
CANALS. 299
CAMERA Obscur A. An instrument for a similar purpose as the foregoing,
but constructed upon different principles, the rays from the object being caused
to pass through a convex glass, on to a white surface placed opposite to the
glass, in a darkened chamber. A camera obscura may be constructed as
follows: darken a chamber, and into a small aperture made for the purpose in
one of the window shutters, fit a lens, either plano-convex, or convex on both
sides; and at a due distance, to be determined by experience, place a paper or
white cloth, and the objects opposite the lens will be shown upon the paper in
their natural colours and proportions, but in an inverted position; by placing a
concave lens between the centre and the focus of the first lens, the images will
be shown erect. If the aperture do not exceed the size of a pea, the objects
will be represented without a lens. .
CAMPHOR. There are two kinds obtained from the East, one from Sumatra
and Borneo, the other from China and Japan. It is extracted from the roots,
wood, and leaves of the laurus camphora, the roots affording the greatest quantity.
It is distilled in large iron pots, to which earthen heads, stuffed with straw, are
adapted, and provided with reservoirs. Most of the camphor becomes con-
densed in the solid form amongst the straw, and part comes over with the water.
The refinement of this camphor is performed by sublimation in low flat-bottomed
glass vessels placed in a sand bath, and the camphor becomes concrete in a pure
state against the upper part, whence it is separated after breaking the glass with
a knife. Lewis asserts that no addition is necessary in the purification of
camphor, but that the chief point consists in managing the fire, so that the
upper part of the vessel may be hot enough to bake the sublimate together in
a cake. Chaptal says, that the Dutch mix one ounce of quick lime to every
pound of camphor, previous to distillation. Mr. Gray states, that two pounds
of quick lime should be added to each hundred weight of rough camphor, and
the sublimation be performed in a very gentle heat. Camphor is likewise
obtained from thyme, rosemary, and other vegetable substances. Purified
camphor is a white, concrete, transparent, extremely volatile, and inflammable
substance, of a powerful fragrant odour, and acrid taste. It is insoluble in
water, but soluble in alcohol, ether, and the essential oils. It is used in the arts
for assisting the solution of resins; also in medicine.
CAMPHORIC ACID. An acid obtained by repeated distillation of nitric
acid upon camphor. It appears in the form of crystals, soluble in alcohol, oils,
and mineral acids. It also dissolves easily in hot water, but requires about 200
parts for its solution at the ordinary temperature.
CANAL. An artificial cut in the ground, supplied with water from rivers
or springs, &c. in order to form a navigable communication between one place
and another, and also for supplying towns with water. The advantages to be
derived from canals were not unknown to the ancients. Egypt, from the
remotest antiquity, contained a number of canals, dug to receive and distribute
the waters of the Nile at the time of the inundation; but the most celebrated
canal in that country was that which connected the Nile with the Red Sea,
which was completed under the second Ptolemy, and was four days’ journey in
length. It was subsequently neglected, but was afterwards re-opened by one of
the caliphs, in 635, after which it was again neglected, so that it is difficult to
trace the remains of it at the present day. The aqueducts of the Romans were
a species of canal, and they had many also for draining the water from over-
flowed grounds; and attempts were made (although unsuccessfully) by one of
the emperors, to cut through the Isthmus which joins the Peloponnessus to
Greece. But China, in the number and extent of its canals, far exceeds all
other nations, there being scarcely a town or village that is not washed by the
sea or by a river, but has a canal. The Great, or Royal Canal, is the most
magnificent work of the kind in the world; it is 825 miles in length, 50 feet in
width, and 9 feet deep, and extends from Canton to the northern frontiers of
the empire. Most of the countries in Europe are provided with one or more
works of this kind : those of Holland, from their number and the admirable
mode in which they are managed, have long been the theme of travellers; but
perhaps the most stupendous work of the kind is the canal of Languedoc, in
300 CAN AI.S.
France, which forms a junction between the Mediterranean and the Atlantic.
It was begun in 1666, and finished in fifteen years. The breadth is 144 feet,
including the towing paths; the depth is 6 feet, and the length 64 French leagues,
and it has 114 locks. Although this country at the present day is superior to
any nation in Europe (with perhaps the exception of Holland), in the number
and magnitude of its canals, it was one of the last to adopt this important
improvement; for if we except the New River Cut for supplying London with
water, England, up to the middle of the last century, had not a canal worthy
of notice; and the honour of their introduction is due jointly to the spirit and
perseverance of the Duke of Bridgewater, and to the skill and talents of the
celebrated Mr. Brindley. The duke had at Worsley, about seven miles from
Manchester, a large estate, rich in coal, which had been hitherto useless, on
account of the expense of land carriage; he therefore consulted Mr. Brindley
as to the practicability of forming a communication by water, who, having sur-
veyed the ground, and declared the scheme to be practicable, the duke, in 1758,
obtained an act to make a navigable cut or canal from the township of Salford,
to or near Worsley Mill, and to a place called Hollens Ferry, in Lancashire;
but extending his views as the work advanced, he subsequently obtained two
other acts, the first to carry it over the Irwell to a place called Longford-bridge,
and the second to extend it from Longford-bridge to a place on the Mersey
River, called the Hempstones. The whole navigation was then proceeded in
and completed, being more than 29 miles in length, and having, at its fall into
the Mersey, locks which let it down 95 feet. It should be remarked that the
locks were formed at Runcorn, instead of the Hempstones. The completion of
these works quickly rendering apparent the important advantages of canals to
the commercial and manufacturing interests, new undertakings of the kind
succeeded each other with such rapidity, that the bare enumeration of those
existing at the present day would occupy more space than we could spare for
the purpose. Amongst the principal are the Grand Trunk, or Staffordshire
Canal, forming a communication between the Trent and the Mersey, and, con-
sequently, between the German Ocean and the Irish Sea; the Thames and
Severn; the Birmingham Canal; Peak Forest and Grand Junction, in England;
and the Caledonian Canal, in Scotland. The total number of canals in Great
Britain is 103; the total extent 2688 miles; and the capital sunk in their con-
struction is computed at upwards of thirty millions sterling. With two or three
exceptions, they were all constructed by the combined exertions of private
individuals; and important as these works are now become, none of them were
projected prior to 1755. The particular operations necessary for making arti-
ficial canals depend upon a variety of circumstances. When the ground is
naturally level and unconnected with rivers, the execution is easy, and the
navigation not liable to be disturbed by floods; but when the ground rises and
falls, and cannot be reduced to a level, artificial means of raising and lowering
vessels must be employed. The ordinary expedients are either inclined planes
or locks. The first of these methods, viz. the inclined planes, is chiefly resorted
to in cases where the canal is so very scantily supplied with water that its
economy becomes an object of the first importance. For this purpose, an
inclined plane of masonry is constructed, extending from one level to the surface
of the next above it, and the boats are hauled up the plane upon a kind of
cradle or sledge, furnished with rollers, and this, it is said, was the only method
employed by the ancients, who appear to have been ignorant of the nature and
utility of locks. The engraving on the opposite page represents an improvement
upon this method of passing boats from one level to another, by which the boats
maintain their parallelism whilst ascending the inclined planes. It is the
invention of Mr. J. Underhill, of Parkfield Iron Works, near Wolverhampton.
The following is a description of the engraving : a the higher level of the
water of the canal; b the lower level; the bottom of the canal is a little
excavated at each of these places, to admit of a kind of cradle carriage to be
sunk sufficiently deep for a boat to be floated on to or off it. At c is represented
a laden boat, placed upon the upper level in its carriage ff; and at d another,
similarly circumstanced upon the lower level, in its carriage 9 g. Each of them
CANALS. 301
is attached by strong chains to a drum-wheel h, properly mounted in a strong
framing, and worked by a steam engine or other adequate power. The carriages
are mounted upon two pairs of solid iron wheels, which run upon railways
that connect the upper
and lower levels. These
railways form two inclined
planes for the ascent of |
the carriage, and the same
for its descent, whilst the
two slopes are connected
at top by a horizontal
plane. This will be clearly
understood by reference.
to the diagram. The boat
e is there represented in
its carriage, and ascend-
ing the double rails or
planes r, the hind wheels
being on the top rails, and
the fore wheels on the
bottom rails, but confined
in their track by the pa-
rallel bars o above, which
preserve the carriage from
shifting out of the hori- is
zontal position. Before is
arriving at the top, the É
fore wheels open two
latches l, having counter-
balance weights, and both
hind and fore wheels
arrive together on the top
of the horizontal line of
rail. On drawing it for-
ward for the descent into
the lower level of the
canal, the latches l become
closed, and the carriage is
sent forward, as shown by
the dotted lines ate, before
descending, when the fore
wheels open the latches
for the hind wheels to
enter between the parallel
bars; g g shews the boat
and carriage delivered on
to the lower level of water,
where the carriage sinks
to a sufficient depth to
allow the boat to float
away from it. The pa-
tentee proposes to employ
imilar machinery for
raising weights on land.
But where canals have an
abundant supply of water,
the usual method of trans- S SSS ss----sº
mitting boats from one level to another is by locks. A lock is a long narrow
passage connecting two contiguous levels, of sufficient width and length to
receive a boat, and in depth extending from the top of the upper level to the
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302 CANALS.
bottom of the lower level. The sides are usually formed of masonry, and at
each end is a pair of strong gates, turning upon centres strongly secured to the
walls. The gates next the upper level extend only to the bottom of that level,
but those at the lower level extend the whole depth of the lock. These gates
are opened and shut by means of long projecting arms or levers, and when
closed, the gates meet in an angle pointing up the stream. At the upper end of
the lock is a sluice, by which the water can be admitted into the lock from the
upper level; and at the lower end is another sluice, by which the water can be
discharged from the lock into the lower level. The operation of passing a boat
from one level to another is as follows: suppose it be required to pass the boat
from the upper level to the lower, and that the water in the lock is at the same
height with the water in the lower level, and that the gates at each end of the
lock are closed; the sluice at the upper end is first opened, and the water
admitted into the lock from the upper level; and when it attains the same height
in the lock as in the upper level, the sluice is shut, the upper gates opened, and
the boat hauled into the lock. The upper gates are then closed, the sluice at
the lower end of the lock opened to discharge the water into the lower level,
and when the water stands at the same height in the lock as in the lower level,
the sluice is shut, the lower gates opened, and the boat hauled out of the lock
into the lower level. In the reverse operation, or passing a boat from the lower
level to the upper, the water in the lock is first reduced to the height of the
water in the lower level, when the lower gates are opened to admit the boat
into the lock, after which they are closed, and water admitted into the lock
from the upper level, until it stands at the same height in each, when the upper
gates are opened, and the boat passed into the upper level. The operation just
described is extremely simple and easy, but it will be seen that at each transit
of a boat in either direction, a lock full of water is drawn from the upper pond
and lost. This loss is of such consequence on some canals, that the water is
pumped back to the upper level by a steam engine, and numerous plans have
been proposed for avoiding or lessening this loss. On the Regent's Canal the
locks are double, and placed side by side, with a sluice in the middle pier to
admit the water from one lock into the other. In passing a boat from the upper
to the lower level by these locks, the water is not discharged from the full lock
into the lower level, in the first instance, but it is admitted into the empty lock
until it stands at the same height in each; after which the sluice in the middle
pier is shut, and the remainder of the water discharged into the lower level, by
which means only about half a lock full is lost at each transit. Mr. Brownill,
of Sheffield, has proposed a plan for passing boats from one level to another,
with very little loss of water, which we shall endeavour to describe with the
assistance of the engraving on the following page, which represents a vertical
section of the apparatus. a is the upper level of the canal; b the lower level;
c c section of the end walls of the shaft in which the cradle works; d one of the
side walls of the same; e the gate of the upper level; f the gate of the lower
level; g g a number of bearings, supporting the horizontal axis h, on which
are placed the large sheaves k k, over which the suspending chains run ; to one
end of these chains is attached the cradle o, and to the other end is hung the
counterbalance l (shown in dotted lines), which rises and falls in a side shaft,
there being a similar counterbalance in another shaft on the opposite side of
the main shaft d ; these two counterbalances are made to act together by
means of the large wheel n acting on a similar wheel on the axis of the opposite
counterbalance. This arrangement the inventor terms his double union lift.
The cradle o has a sluice at each end, fitted with smaller sluices p p; it has
also a double bottom q; r is a short lever at the lower end of the cradle,
which does not prevent its ascent, but as soon as it arrives above the inclined
plane s, its upper end turns over, and rests against the dotted lever t, termed
the release lever; and upon allowing the cradle to descend a little, the lever
*; acting upon the inclined plane s, forees the cradle over against the sill of
the gate of the upper level. At the opposite corner of the cradle is a similar
apparatus (not shown in the drawing,) to act upon the inclined plane r. To
pass a boat from the lower level to the upper one, the cradle is forced by
CANALS. 303
the pressure of the lever upon the inclined plane r, close ever to the entrance of
the lower level; the small sluices p p are then opened to admit the water into
the cradle, until it stands at the same height in it as in the upper level, when
the larger sluice in the cradle and the gate f are opened. The boat is now hauled
into the cradle, after which the gate and sluices are again closed, and the
counterbalances (which consist of large iron tanks filled with water), being at
the top of their shafts, as much water is let out from the double bottom q of
the cradle o as will cause the counterbalances to preponderate when they descend,
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planes s ; but as there is a small portion of water in the side shafts, the coun-
terbalances are checked in their descent on reaching this water; they then rise
slightly, and allow the cradle to settle on the inclined plane s, which forces it
against the upper level; the small sluice p is next º and as soon as the
water stands at the same level on each side of the large sluice, the latter and
the gate of the canal are opened, and the boat can then pass into the upper
level. If now a boat is to be passed from the upper to the lower level, it is hauled
into the cradle; the gate e and the large sluice, and the smaller sluice p are all















































































304 (..ANDLES
shut, and as much water is admitted in the double bottom p of the cradle (from
sa side reservoir, shown dotted,) as will give the cradle a preponderance; and the
release lever being let go, the lever r turns over, and the cradle descends, and
on reaching the bottom of the shaft it is passed into the lower level in the
manner described for passing it into the upper one. The ends of the cradle
must be covered with stuffing of some kind, to prevent as much as possible the
escape, of the water when the sluices are open.
CANDLE. A cylindrical mass of tallow, or other concrete oleaginous
matter, having in its axis a cotton or other wick, and employed to afford
artificial light. Next to tallow, the substances most extensively used are wax
and spermaceti. Some valuable substitutes for these have recently been dis-
covered and introduced in the manufacture of candles, which we shall give
an account of in this article, after having described the processes employed in
the production of the former. There are two sorts of tallow candles, dips and
noulds ; the former being made by dipping the wicks in melted tallow, the
latter, by casting, or pouring the fluid tallow into moulds containing the wicks
stretched longitudinally throughout their centres. The cotton used for making
the wicks is loosely twisted, and is prepared for the manufacturer in large balls,
who draws out a thread from each of five, six, or more balls, (according to the
thickness of wick required,) and cuts, them off to the length of the intended
candle. The apparatus for cutting the cotton is simply a smooth board, made
to fix on the knees; on the upper surface is the blade of a razer, and at the
required distance a piece of cane is fixed, around which the cotton is carried,
and being thence brought over the edge of the razor, is instantly separated.
The next operation, called “pulling the cotton,” consists in drawing the threads
through the hand, and removing knots or other unevenesses. The cotton is
next “spread,” or extended between two rods, about half an inch diameter, and
three feet long; these are called broaches. In dipping candles by hand, the
workman takes two broaches at a time, strung with the proper number of wicks,
and holding them equidistant by means of the second and third fingers of each
hand, he immerses them in a vat containing the fluid tallow, three times suc-
cessively for the first lay or coat, then holds them for a while, over the vessel
to drain, and afterwards suspends them on a rack above, where they continue to
drain. When this first coating of tallow has solidified, the workman proceeds
in like manner to give them their second coat, by dipping them twice before
hanging them again to drain and cool. The number of lays or coats thus given
to the candles depends upon the thickness they are required to be. During the
operation the vat is supplied from time to time with fresh tallow, kept at a
proper temperature by means of a gentle fire underneath it. Tallow-chandlers
have of late years, however, generally availed themselves of a very simple and
convenient piece of mechanism for aiding them in their dipping process. Five
or six of the broaches, filled with the cotton wicks as already described, are
fixed at both their ends into a movable frame, which is suspended over the vat
upon one extremity of a lever, and is counterbalanced at the other by weights
in a scale, which are increased as the candles become heavier. By this arrange-
ment it is obvious that the workman has only to guide the frame in dipping the
candles, and not to support the weight between his fingers, as before mentioned.
It is said that other mechanical contrivances have been introduced for the same
purpose, but we are not aware of any so simple and efficient. The mould in
which moulded candles are cast consists of a frame of wood, and several hollow
metal cylinders, generally made of pewter, of the diameter and length of the
candle wanted, and having an aperture at each end for the cotton to pass
through, which is performed by a wire, the cotton being fastened so as to keep
it straight and in the centre of each mould. Tallow being poured into these
moulds, the candles are suffered to cool and harden, when they are readily
withdrawn out of the tubes. The kind of candles called rush-lights, differ only
by their containing a rush as a substitute for the cotton wick, which prevents
the necessity of snuffing. Lately, however, small cotton wicks have been
introduced, which do not require snuffing; these burn with a steadier light, and
are not so liable to go out as those with rushes.
CANDLES 305
Wax candles are also of various kinds; they are made of cotton or flaxen
wicks, and covered with white or coloured wax, which is performed either by
the ladle or by the hand. In making them by the ladle, a dozen of them are
tied by the wick at equal distances round an iron ring, suspended over a large
basin of copper, winned on the inside, and full of melted wax; a large ladleful
of this wax is gently poured on the tops of the wicks one after another, and the
operation continued till the candles arrive at their destined dimensions. The
first three ladlesful are poured on to the tops of the wicks, the fourth at the
height of three-fourths, the fifth at one half, and the sixth at one-fourth, in
order to give the candles their proper form, which are then taken down and
smoothed by rolling upon a walnut-tree table, with a smooth box-wood instru-
ment, which is continually moistened with hot water to prevent the adhesion of
the wax. In making wax candles by the hand, the workmen begin to soften
the wax by working it several times in hot water, contained in a deep narrow
cauldron. A piece of the wax is then taken out and disposed by little and little
around the wick, which is hung on a hook in the wall, by the extremity opposite
to the neck, so that they begin with the large end, diminishing still as they descend
towards the neck. In other respects, the method is nearly the same as in the before-
mentioned. There is, however, this difference,—that in the former case, water
is used to moisten the instruments, while in the latter, the hands are lubricated
with oil of olives, or lard, to prevent the adhesion of the wax. Wax tapers are
drawn after the manner of making wire. By means of two large wooden rollers
the wick is repeatedly passed through melted wax contained in a basin, pro-
vided on one side with an instrument full of holes, through which the cylinder
of wax also traverses until it has obtained the required size.
Candles are made from spermaceti, the process being very similar to that
employed in making them of tallow ; they are also made of various
mixtures of tallow, spermaceti, and wax; certain proportions of which con-
stitute the article termed composition candles. The meritorious investi-
gations of M. Chevreul, concerning the true nature of fatty substances, which
were published a few years ago in the Annales de Chimie, appear to have
opened a wide and diversified field for the operations of the manufacturer and
the experimentalist. By dissolving fat in a large quantity of alcohol, and
observing the manner in which its different portions were acted upon by this
substance, and again separated from it, M. Chevreul found that fat is composed
of an oily substance, which remains fluid at the ordinary temperature of the
atmosphere, and of another fatty substance which is much less fusible. Hence
it follows that fat is not to be regarded as a simple principle, but as a combi-
nation of the above two principles, which may be separated without alteration.
To the former of these substances, which melts at 4500 Fahr., and has
very much the appearance and properties of vegetable oil, M. Chevreul
gave the name of elain, and to the latter, which melts at 1000, he gave
the name of stearin ; this is separated from the former by crystallization
in the form of small silky needles, while the elain is obtained by evaporating
the spirit. M. Bracconet subsequently employed a simpler process to obtain the
elain and stearin; he squeezed the tallow between folds of porous paper, which
absorbed the elain, leaving the stearin between ; the paper being afterwards
soaked in water, yielded up its oily impregnation. The principle of M. Brac-
conet's process is now extensively applied by manufacturers, who employ
powerful presses to squeeze the fluid oil from the tallow In the year 1825,
. Gay Lussac, the celebrated French chemist, also took out a patent for this
country for the employment of the stearin (termed likewise margaric acid from
its chemical properties) in the manufacture of candles; the patent likewise ex-
tending to a new mechanical construction of candles. Of the several processes
that may be employed for obtaining the margaric acid for this purpose, two are
particularly descriptive in the specification, namely, saponification and distilla-
tion. The first is to be effected by incorporating any of the alkalies with the
fat, as is done in the making of soap, and then decomposing the soapy fluid by
an acid that has the greatest affinity to the peculiar alkali employed. It is
recommended that the decomposition be effected in a large quantity of water,
306 CANDLES. ...”
heated by steam, which should be kept well stirred. Being afterwards allowed
to rest, the products will float on the surface in a condensed and solid form. If
the tallow or fat, thus purified from the matters soluble in water, should still
contain any of the salts employed in the previous process, it is to be washed by
additions of fresh quantities of warm water, until they are perfectly discharged.
This being done, and the mass of fat having become solid by cooling, it is to be
subjected to the action of a powerful press, similar to those used for expressing
oil from seeds, when the fluid oleic acid (or elain) will run off, leaving the mar-
garic acid in the press, from which product the candles are to be made. The
distilling process is conducted by exposing the fat, in an ordinary still, to the
heat of a furnace. Steam is also to be introduced into the still to facilitate the
operation, and to carry over those products which are soluble in it, through the
worm or condenser, into a receiver. Care must be taken in regulating the heat
of the furnace, to prevent discolouring the materials in the still The fat thus
prepared is to be purified by washing, and then subjected to pressure as in the
previously described process. For the more perfect purification of the fat, both
the foregoing operations of saponification and distillation may be combined, and
the residue after subjected to pressure. The margaric acid may also be bleached
by exposure to the air and sun the same as in the bleaching of wax ; the oleic
acid, or fluid oil, may also be whitened by similar means, and be applied
generally to the same purposes as the vegetable oils. The form of M. Gay
Lussac's candles is that of hollow cylinders, through which a stream of air
passes to the wick (on the principle of the argand burner in lamps) for the pur-
pose of producing a perfect and vivid combustion of the tallow. He directs that
the wick beformed of cotton yarn twisted rather more closely than usual; this yarn
is to be wound spirally round a metallic rod or thick wire, in the same manner as
wire is sometimes coiled round the large strings of musical instruments. These
rods, covered as described, are to be inserted into the moulds ºn
used for making candles; and when the candles have been cast, and *
the tallow become hard, the wires are to be withdrawn, leaving
the wicks behind in the candles with a perforation, or air passage,
equal to the size of the rods, throughout their whole length.
We have thought it proper to introduce this account of M. Gay
Lussac's specification of his patent, because it affords clear and g
judicious instructions in conducting similar operations. The pro-
cesses possess scarcely any originality in the mode of procedure;
and as regards the invention of the candle itself, the French
chemist is just twenty years behind two of our own countrymen,
namely, Messrs. Desormeaux and Hutchings, who took out a
patent for the identical contrivance in the year 1805. It is per-
haps worthy of notice here, that this invention affords a very
remarkable proof that many individuals may, without communi- #
cation or knowledge of each others' ideas, invent precisely the #
same thing. The writer of this article, about ten years ago, spon-
taneously thought of the same contrivance, and made a candle of i ;
the kind, which is represented in the annexed cut. The dotted º
lines at a mark out the central aperture for the air; and the #
wick, which is bedded in the middle of the thickness of the hollow ſº
cylinder of tallow, is a common argand wick. This candle,
|
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although not fabricated in a workmanlike manner, gave good
indications of success under proper management. Upon mention-
ing the project to some friends, we learned to our surprise that ||
several other persons had entertained the same propositions, each |
person imagining himself to be the sole inventor. In like #
manner we were informed by the before-mentioned gentleman,
Mr. Desormeaux, that he had patented the invention at the time ;
stated; that a large manufactory was commenced for the purpose t
of making the article, with every probability of success; and that
the reason why the manufacture of them was not carried forward, had no refer-
ence to the practicability of the scheme. Seeing that the subject has been
j
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CANDLES, 307
taken up by scientific as well as practical men, we are confirmed in our opinion
that imporiani results ulay yet fiow from prosecuting the pian, if undertaken
by some intelligent person. We are not wholly indebted to the animal kingdom
for a supply of the material for candles, several vegetable oleaginous substances
having been recently introduced as valuable substitutes. On the 2d of Novem-
ber, 1829, a patent was granted to Mr. John Soames, jun. of Spitalfields, for
the right of separating the constituent principles of the cocoa-nut oil of com-
merce, which, from its consistence at ordinary temperature, is also called
“butter of cacao.” Before the date of this patent, cocoa-nut oil was of very
limited utility, owing to the presumed necessity of artificial heat to render the
mass sufficiently fluid to be burned in lamps, and to that apparent want of
solidity which is required in the manufacture of candles. Mr. Soames's pro-
cess for separating the fluid from the solid matter in cocoa-nut oil is as follows:–
the oil is put into strong linen bags, 2 feet long, 6inches wide, and 14 inch thick;
these are covered with stout sack-cloths made for the purpose, and are laid
flat upon the horizontal bed of a hydrostatic press, leaving a small vacant space
between the bags. Pressure is then given to them, and continued until the oil
ceases to flow, or is only given out by drops slowly. This oil being received
into a cistern, is allowed to stand a little time to deposit its impurities, after
which,it is drawn off clear, and preserved for burning in lamps, &c. The solid
portion being now taken out of the bags in the press, is next to be purified from
the other vegetable principles with which it is usually combined, such as fibre,
mucilage, &c. For this purpose it is put into a covered boiler of tinned
copper, which is immersed in a water-bath to prevent the liability of an excess
of heat; there is then added to it two parts, (or two per cent.) by weight, of
sulphuric acid, of spec. grav. 1.8, diluted with six parts of water. Boiling then
coagulates and precipitates the foreign matters, which may be separated by
skimming, straining, or filtering, while warm in the fluid state, and by allowing
them to settle in the cold state. The substance thus obtained is of firm con-
sistence, and forms a valuable material in the making of candles that are now
extensively used. In the Quarterly Journal of Science, an interesting account
is given of the piney tallow tree of India, which we introduce in this work, as
the writer observes, that “it may be imported into this country at less than
one-fourth the price of wax; and that although it does not possess all the
advantages of that substance, it is considerably superior to animal tallow.” This
substance, he says, “is a concrete inflammable, partaking of the nature of wax
and oil, which, from its appearance, may not inaptly be termed a tallow. It is
in use only in the town of Mangalore (province of Canara), and is there em-
ployed medicinally as an external application for bruises and rheumatic pains;
and likewise, when melted with the resin of the same tree, is used as a substi-
tute for tar in º the bottoms of boats. The method of preparing this
material is simply to boil the fruit in water, when the tallow is soon found to
rise to the surface in a melting state, and on cooling forms a solid cake. Thus
obtained, the piney tallow (piney is the native name of the tree which produces
it) is generally white, sometimes yellow, greasy to the touch, with some degree
of waxiness, almost tasteless, and has a rather agreeable odour, somewhat
resembling common cerate. It melts at a temperature of 9749, and conse-
quently remains solid in the climate of India, in which respect it differs from
palm or cocoa-nut oil : wrapped up in folds of blotting paper, and submitted to
strong pressure, scarcely sufficient oil, or elain, as it is termed by M. Bracconot,
is expressed to imbue the inmost fold. Its tenacity and solidity are such,
that when cast in a rounded form of nine pounds' weight, the force of
two strong men was not sufficient to cut it asunder with a fine iron wire,
and even with a saw there was considerable difficulty in effecting a division.
When manufactured into candles, it comes with facility from the moulds, thus
differing from wax, which does not readily admit of being cast; it gives as
bright a light as tallow, and has the advantage of that material in being free
from unpleasant smell, and in not emitting a disagreeable odour when extin-
guished. It unites, in all proportions, with wax, spermaceti, and tallow; and
forms compounds with the two former, intermediate in their melting points,
308 CANDLES.
according to the proportion in their ingredients, and better adapted to the
purpose of making candles than the pure and more fusible substance itself.”
With the view of ascertaining the comparative combustibility of piney tallow,
candles of the materials undermentioned were cast; one mould was used for
all, and the wicks were composed of an equal number of threads. Having
been accurately weighed, they were burned for one hour in an apartment in
which the air was unagitated, and at a temperature of 55°.
Weight in Weight at
grains when the end of Loss
- lighted. one hour.
Wax . . . . . . . . . 840 719 121
Half wax, half piney tallow .. 770 631 1 39
Spermaceti . . . . . . . 760 604 156
Half sperm, half piney tallow . 777 625 152
Animal tallow . . . . . 811 703 108
Half tallow, half piney tallow .. 792 681 11 I
Cape wax . . . . . . . 763 640 123
Piney tallow . . . . . . 812 702 110
In the year 1830, a solid substance, resembling wax in most of its properties,
was obtained by M. Manicler, a French chemist (lately deceased), from
palm oil, an English patent for which was taken out in conjunction with
Mr. James Collier. The specification states that the process consists in placing
the palm oil, or butter of palm, in a metallic vessel or boiler, made of tinned
iron, and provided with a close cover and safety valve, upon the principle of
Papin's Digester; water, in the proportion of about one-sixth part to the sub-
stance being added. The vessel being well closed, it is submitted to the action
of fire, so as to raise the steam to a pressure of two or three atmospheres,
which operation is to be continued for two hours. After the material has been
thus prepared, it is to be put into wrappers of linen or woven horse hair, or
both may be used, and submitted to powerful pressure: by this means the
elain, or fluid oil, is separated, and the stearin remains in the wrappers in a
solid state. Both these products are of a yellowish brown colour, and require
a process of bleaching to deprive them of it. We have seen candles made from
the stearin of palm oil, which were very little inferior to wax in illuminating
power; they were cast in moulds, from which they readily separated by con-
traction when cold, in this respect possessing an advantage over wax. The
odour emitted by the substance is like palm soap, and is generally considered
rather agreeable than otherwise. It may, perhaps, be necessary to explain to the
general reader that the palm oil of commerce, and that to which the last
mentioned patent relates, is the produce of a tree growing abundantly in Africa
and South America, where, as well as in other parts of the world, it is obtained
from the outer shell or pulpy rind of the palm nut, while the kernel of the nut
contained within the inner indurated shell is thrown away as useless in the
preparation of oil or other oleaginous articles of commerce. These kernels,
however, have been recently found to abound in oleaginous matter of superior
quality, eminently calculated for the production of candles, besides generally for
those purposes for which fluid and concrete oils are used. For the introduction
and application of this valuable (refuse) matter, the public is indebted to
Mr. John Demeur, who has recently taken out a patent for this interesting
discovery. The process described by the patentee in his specification is as
follows: “I first subject the kernels to a slight heating in an oven, or other
convenient apparatus, carrying the process only so far as to render the kernels
bomparatively crisp and brittle when cold, which facilitates the subsequent
bperation of grinding them to a paste in a mill. This paste I dilute with one-
fourth of its weight of boiling water, and then put it into bags (of the usual
kind employed in oil mills), wherein I subject it to mechanical pressure by the
ordinary mechanism employed for similar purposes, preferring, however, to
tºº. the said bags containing the paste between heated metallic plates. By
he joint action of heat and pressure so applied, the oleaginous matter is
CAN i LES. 309
copiously exuded through the interstices of the bags, and is collected in suitable
receivers to undergo a purification. This purification I usually effect by remelting
the last mentioned product, and filtering it whilst in a fluid state; and if it be
desired to purify or refine it still farther, or to remove the slight tinge of colour
it may yet possess, I again melt it in a metallic vessel coated with tin, and mix
there with, by agitation or stirring, some very dilute sulphuric acid. By this
process the impurities are precipitated, or subside, by rest, to the bottom of the
vessel, and the oleaginous matter floats above the water, whence it is removed,
and subsequently consolidated, by evaporating the aqueous particles that were
commixed with it in the previous operation. The product resulting from the
last described process is a white and partially concrete matter, as it consists of
the two distinct substances, termed elain and stearin, the former of which is
fluid, and the latter solid, at our ordinary atmospheric temperature. To separate
these, they are subjected again in bags to mechanical pressure, without the aid
of artificial heat, if the weather be warm; but if the air be under 650, the
application of a slight degree of heat will assist the operation, and cause a fine
fluid oil to be expressed, leaving the stearin in the bags of a similar consistence
to wax or spermaceti, and from which candles, ...; inferior to those fabri-
cated of the last mentioned substances, and very superior to those of tallow,
are made. Having noticed the several important materials that have been
introduced into the modern manufacture of candles, we shall proceed to describe
some very recent and ingenious improvements in their construction and com-
position, which have been the subject of patents.
Dr. Bulkeley, of Richmond, in Surrey, took out a patent, dated January 26,
1830, for a plan of making tallow candles with an exterior casing of wax, and
also for effecting a saving in the material used for wicks, as well as to obviate
the necessity of snuffing. He uses a metallic mould, of the description generally
employed in the manufacture of mould candles, and fills it with melted wax.
Now, as the portion of the wax which is in contact with the interior surface of
the mould will become, by the conducting powers of the metal, first cooled or
set, as it is termed, the wax remaining fluid in the centre of the mould is poured
off, leaving within the mould a hollow cylinder of wax, which is afterwards
filled with tallow, or any other material which melts at a lower temperature
than wax. With respect to the wick, the patentee introduces a small thread up
the centre of the candle, for the purpose of constituting a guide for a short
cotton wick, which is plaited with a piece of straw within it, to receive the
thread. This short wick rests on the surface of the tallow, which it raises by
its capillary attraction for the supply of the combustion; and as it descends
upon the thread as the tallow is melted, the top of it is never removed so far
from the tallow as to carbonize and require snuffing, which is the case with
wicks of the ordinary construction. The ordinary mode of manufacturing wax
candles, described in the early part of this article, has, we understand, been
resorted to, on account of the presumed difficulty of removing them from the
moulds, to which they firmly adhere, if cast therein. To obviate this difficulty,
Dr. Bulkeley places a block of box-wood, having a cavity in it to receive the
lower ends of the candle, in contact with the annular edge of the mould; then
striking the block a few smart blows with a mallet, he detaches the candles from
the moulds.
A patent was also granted on the 4th February, 1830, to Mr. Charles T.
Miller, of Piccadilly, Westminster, for certain improvements in making candles.
These consist in the use of a small glass ring, which is placed over the wick,
and descends as the candle burns. The object in view is to prevent the candle
from wasting or guttering, which it effects by the glass ring conducting a greater
quantity of heat to the centre of the candle than that which reaches the exterior;
so that candles provided with this ring burn hollower in the centre than others,
and the exterior tallow, or composition of which the candles are made, stands
higher, and descends to the wick as soon as it is melted. The method of manu-
facturing the candles with the glass rings, as described by the patentee, consists
in putting the ring over the wick after it has been placed in the centre of the
mould, which, being inverted, as it is while being filled with the oleaginous
R IR
310 CANDLES.
matter, the ring descends until it reaches that part of the conical extremity of
the mould which is equal in diameter to the exterior of the ring, when it rests,
and becomes fixed in the candle. From an experiment which we have witnessed
with spermaceti candles, made by Mr. Miller according to the plan described,
they appear to answer the purpose intended.
Mr. John Murray, in a letter to the editor of Brewster's Journal, states that
tallow candles may be materially improved by previously steeping the cotton
wicks in lime water, in which there has been dissolved a considerable quantity
of the nitrate of potass. The chlorate of potass is preferable to the nitrate,
but the great expense of the former salt precludes its employment on the large
scale. The wicks should be well dried before the tallow is put to them. By
this process, Mr. Murray states that the candles afford a purer flame and a more
brilliant light; the combustion of the wick is so complete as to render the
snuffing of them nearly superfluous; and that they do not run or gutter.
With similar objects in view, Mr. William Palmer, of Wilson-street, Finsbury-
square, London, obtained a patent, dated 10th August, 1830. He applies to
about a tenth portion of the strands composing the wick, a quantity of bismuth
in a finely divided state, or else the nitrate, or any other similar preparation of
bismuth. The portion of wick thus prepared is to be surrounded with more
strands, till it becomes half the thickness required for the wick. It is then to
be cut into pieces, corresponding in length with twice that of the candle for
which it is intended. The wick is next twisted spirally round a thick wire in
contrary directions, a notch being made in the lower end of the wire to receive
the middle of the wick; and the upper end is bent into a rectangular loop, to
retain the two ends of the wire together, and to facilitate its removal when the
making of the candle is completed, which is to be effected by either moulding
or dipping in the usual manner. The combustion of the wicks of candles
manufactured in this way, with a portion of bismuth in combination with the
wick made of the double spiral form, causes the two upper extremities of the
spiral, in the act of burning, to curl over to the opposite sides of the candles,
where they are accessible to an additional quantity of oxygen, and the com-
bustion is in consequence so intense as to leave no carbonaceous matter to
impede the light, or to require removal by snuffers. We shall close our
article on this subject by the translation of a French Brevet d’Invention, granted
to M. Lorraine, of Paris, for the manufacture of perfumed imitative wax candles,
which we think is calculated to afford some useful practical hints to the British
tallow chandler. “Candles made of tallow only,” observes M. Lorraine, “are
unctuous, opaque, greasy, little sonorous, especially in summer, liable to run or
gutter, and readily acquiring a rancid smell. These inconveniences are avoided
by putting fat, which has been melted and run into cakes, to ferment in a stove
where the heat is moderate; this fat distils, and throws off an oily liquor, which
is removed with a piece of linen or a sponge. To free the grease from the
fleshy and fibrous parts by which it is accompanied, it is first chopped, and
after being washed in several waters, it is boiled with a given quantity of Roman
alum. The alum soon separates and destroys the heterogeneous parts, and we
obtain a pure clear fat, which will last a very long time. The fat chopped and
melted, is run into buckets full of water distilled from aromatic simples, such
as lavender, thyme, rosemary, &c. The fat and water are beaten together with
a spatula, to effect an union. After forty-eight hours the fat is separated from
the water, by means of a water bath; the water alone is disengaged, and the
aromatic and odoriferous parts remain incorporated with the fat. To complete
the purification, the fat is liquefied and scummed, till no foreign substance nor
water remains: this will be known by the limpid state of the fat, which then
yields only a pure white scum. Still greater purity is obtained by a second
quantity of alum incorporated with the tallow. Before casting or running the
candles, a composition is made of half wax and half spermaceti, which serves to
prepare the wicks. This composition, harder and more cohesive than the tallow,
makes the candles less subject to gutter, to become firmer, last longer, and
require less snuffing. At the moment of removing the pure liquefied tallow from
the fire to cast the candles, a certain quantity of gum Arabic, dissolved in water,
CANN ON. 31 1
and united with a small quantity of wax and alum, is incorporated with it. The
whole are beaten together; and when the tallow has settled well, and cooled to a
certain temperature, it is poured into the moulds. By this preparation, in pro-
portion as the cooling takes place, the foreign substances proceed to, and fix at
the surface of the candles, forming a kind of covering pleasant to the touch,
like wax candles. This covering also prevents the candles from guttering, and
enables a person to handle and even rub them without greasing the fingers, and
without communicating any other smell than that of the aromatics entering into
the composition. The last operation for preventing the guttering of the candles
when burning, and giving more solidity to them, is to prepare some glover's size
very weak, and boiled with another quantity of gum and alum, and to pass a hair
pencil dipped in this size, all over the candles, and the next day after they may be
used. Candles prepared in this way are clear, transparent, sonorous, and last
longer than others; they feel like bougies, and have the colour of pure wax.”
CANNON. In military affairs, a long cylindrical tube for throwing projec-
tiles by the explosion of gunpowder, of such dimensions as to require to be
supported upon a carriage, with liberty to recoil after firing; in which circum-
stance it differs from fire-arms of the smaller sort, as pistols, carabines, &c.
which may be fired from the hand or shoulder, and from an intermediate class,
as musketoons, duck guns, &c., which are fired from a rest. The date of the
invention, and the name of the inventor, are unknown : it is certain that
Edward employed cannon at the battle of Cressy, A. D. 1346; but records are
extant showing that they were known in France as early as the year 1338; and
Isaac Vossius asserts that they were used in China 1700 years ago. For some
time after the invention of cannons in Europe, they were formed of bars of
wrought iron, fitted together lengthways, or of sheets of iron, rolled up and
fastened together; and in both cases hooped with iron rings. They were ex-
tremely heavy and cumbersome, and principally used for throwing large stones
to short distances, like the machines of the ancients which they succeeded.
These were gradually supplanted by brass cannon of much smaller calibre, and
which threw iron and leaden balls instead of stones. These guns were first cast
of a mixture of tin and copper, and from that circumstance called gun-metal;
but subsequently, as the use of cannon became more general, cast iron guns
were used on account of their being much cheaper; and at present, guns for
the naval service, and for batteries, are generally cast of iron, whilst field
pieces and horse artillery, are mostly formed of brass. When the process of cast-
ing guns was first resorted to, the guns were cast with hollow chambers, which
were afterwards perfected by boring; but the present practice is to cast them
solid, and form the cavity entirely by boring. In 1828 a patent was granted to
Mr. Joshua Horton, for a method of forming cannon, and other large cylinders,
of wrought iron or steel, or mixtures of both. The process is as follows:—A
number of bars a a are to be bound together by binding hoops b b, as shown in
Figs. 1 and 3, and placed in a furnace. When they have acquired a welding
heat, they are to be withdrawn and placed on a maundrel, and hammered
together by heavy hammers, and if necessary, heated again until they are per-
fectly united; the bars should be wedge shaped, or wider on the outside than
on the side which is to form the interior of the cylinder; but any of the forms
shown in Fig. 1 will do. If the cylinder is intended for a cannon, the bars
should be thickest at the breach end; and if deemed necessary, the interior may
be formed of steel, by placing a layer of steel bars within the iron bars. The
breach-piece may either be formed in one piece with the rest, or it may be forged
separately and screwed into the gun, as shown in Fig. 4. The trunnions
may also be formed with the gun; but the patentee recommends that they
should be formed in a separate ring, and attached to the gun either by an ex-
ternal screw cut on the gun, and fitting into an internal screw in the ring, as
shown in Fig. 4, or by keys, as in Fig. 2. These separate trunnions the
patentee recommends as possessing great advantages, from the facility with
which the gun may be rendered useless by removing the trunnions, when
necessary to abandon it to the enemy. After the welding is completed, the
piece is to be finished by turning and boring. At the first mention of this
3 i 2 CANNON.
method of constructing guns, it seems similar to that followed at the first intro-
duction; but the earlier cannon formed of iron bars were merely hooped
together, and not welded, as may be seen in several which are preserved at the
Tower of London: nevertheless, it is certain that cannon of smaller calibre,
Fig. 3.
: º
Fig. 4.
Ty.
%
forged of iron, were very early known. In proof of this we may cite the following
curious fact:–In the year 1827, a fisherman whilst fishing in a boat eight miles
to the eastward of Calais, brought up in his net from the bottom of the Sea a
small piece of ordnance of a very singular construction, resembling exactly the
representations of cannon in three ancient historical paintings in the dining
parlour at Cowdry, in Sussex, one of the seats of the late Lord Viscount Montagu.
The first painting represents the march of King Henry VIII. from Calais towards
Boulogne; the second, the encampment of the English forces at Marqueson ; and
the third, the taking of Boulogne, in 1544. . The resemblance will be instantly
perceived by referring to the sketch on the following page; Fig. 1 representing
the cannon as seen in the paintings, and the other figures exhibiting with all its
details the cannon taken by the fisherman. Fig. 1 represents a carriage sup-
porting two pieces of ordnance, which are nearly covered by a kind of hood in
form somewhat like half a cone, the broadest end being next to the shafts, and
the smaller end being constructed with sharp points; the hood probably being
intended as a shield to protect the artillery men from the fire and arrows of the
enemy, and the points as some defence against a charge, . Fig. 2 is a horizontal
view of the new found gun; Fig. 3 a longitudinal section of the same; and
Fig. 4 a bird's-eye view of it; l representing the tail bit, also of iron, forming
part of the cannon, and serving to adjust it with ease in taking aim. The
gun when first brought up from the bottom of the sea was covered with a
sort of petrified rust, about two inches thick, which being removed, the diameter
of the gun at the middle was found to be 3 inches, its bore for the passage of
the bullet 13, inch, and the length, including the tail-piece, 5 feet 11 inches, and
its weight 64 lbs. Upon examination it was found to be still charged, having
in it powder and a leaden bullet; from which circumstance we may conclude
that cast iron balls were not known at the time when the cannon had been


CAN N ON. 313
charged. The bullet had a covering of tow, and weighed 9 ounces; its diameter
1.4 inch. A A and C in Figs. 2, 3, and 4, are three different views of a shifting
breech, which was detached and taken out of the after part of the gun when
required to be loaded with powder; this being charged, and the cartridge pro-
perly secured by driving down an oaken plug over it, the bullet was put into
the gun at the breech, and the shifting breech replaced in its original position,
and firmly secured by an iron wedge D D D, Figs. 2, 3, 4, driven in behind it
horizontally across the gun. The shifting breech is shewn separately in Fig. 5,
Fig. 1.
H I r
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|
r
ſ
|
º
IIIT-H-I-I-I-P- L –
#
and the wedge in Fig.6. E, Fig. 7, is the figure of the after part of the barrel
of the gun, and F is the other half within the dotted circumference, this being
cut off so as to take out and replace the shifting breech with facility. g.g, Figs. 2
and 3, show the leaden bullet in front of the shifting breech. It is a remarkable
fact that the shifting breech appertaining to this cannon is similar in principle
to the patent shifting breech on some fowling-pieces of modern times.
We shall conclude this subject with a description of the apparatus employed for
boring cannon. Formerly the cannons were suspended in sliding frames vertically
over the boring tool, and the tool was made to revolve, the cannon descending

3 14 CAOUTCHOU (',
gradually as the tool bored the interior; but in the present method of boring, the
gun is supported horizontally in a lathe, and revolves, the cutter advancing
in a right line. An apparatus of this description is represented in the accom-
panying figure. The cannon a is accurately centered in the chuck b, and the
collar c, which may be set at any part of the bed d of the lathe to suit the
sº ºs
#########!
==|
length of the gun; e is the boring tool, supported by bearings in the frame f,
and connected to the rack g. The rack is made to advance in a chase mor-
tice h, by means of a pinion k actuated by a weighted lever l. The cannon is
caused to revolve by a band passing over the rigger m, and the operations of
boring the interior, and turning the exterior, are carried on at the same
time. -
CANOE. A sort of boat or vessel used by the natives of various uncivilized
countries. They are generally composed of the trunk of a tree hollowed out,
and are usually impelled by paddles instead of oars. The most singular canoes
are those of the Ladrone Islands, which are adapted to sail with either end
foremost, so as always to expose the same side to the wind. From their great
velocity when sailing, they are commonly called the “Flying Boats,” the
Spaniards declaring that they have been known to go 35 miles per hour.
CANTHARIDES. Insects vulgarly called Spanish flies: they are chiefly
used on account of their vesicating or blistering properties. The insect is about
two-thirds of an inch in length and one-fourth in breadth, oblong, and of a
gold shining colour, with soft wing sheaths, marked with threelongitudinal stripes,
and covering brown membranous wings. The genuine cantharides are sometimes
mixed with other insects of a square form, with black feet, which possess no
vesicating property.
CANTILEVERS. In architecture, pieces of timber projecting horizontally,
used to support the eves of a house, a balcony, &c.
CANVASS. A cloth of hemp, unbleached, and of various degrees of fine-
ness; used principally to form the sails of ships, but also by painters, and for a
variety of other purposes.
CAOUTCHOUC. A soft, dense, elastic, resinous substance, usually called
India rubber, but sometimes very improperly elastic gum. It is obtained from
the milky juice of several plants, the chief of which are the Jatropha elastica,
and Urceola elastica. The juice, which is obtained by incision, is received in
successive coatings on pieces of clay, and dried by the sun, or a fire made from
dried leaves: as fast as one layer is dried, another is added, until it obtains the
required thickness, when the clay mould is broken, and the tough leather-like
substance taken out. The wonderful elasticity of this substance, and its resist-
ance to water, has of late years brought it into extensive use for making water-
proof garments, besides many other purposes. Its solvents are ether, volatile
oils, and petroleum. The ether, however, must be washed with water repeat-
edly, when it dissolves it completely. Pelletier recommends the caoutchouc to
be boiled in water for an hour, then to be cut into thin shreds, then boiled again,
and afterwards put into rectified sulphuric ether in a vessel closely stopped.
Berneard considers the nitrous ether as preferable. When this solution is
spread upon any object, the ether quickly evaporates, and leaves, the surface
perfectly covered with the elastic resin. A solution of caoutchouc in five times
its weight of oil of turpentine, and this solution dissolved in eight times its
weight of drying linseed oil, is said to form the varnish of air balloons,





CAPSTAN. 315
Caoutchouc may be formed into various articles without undergoing the process
of solution. If it be cut into a uniform slip of a proper thickness, and wound
spirally round a glass or metal rod, so that the edges shall be in close contact,
and in this state be boiled for some time, the edges will adhere so as to form a
tube. Pieces may be firmly united by merely heating their edges and pressing
them together. Within these few years Messrs. Hancock and Mackintosh
have obtained several patents for various modes of applying this valuable sub-
stance, which are daily rising into notice. The patent caoutchouc pipes are
formed of alternate layers of solid or dissolved caoutchouc and canvass, or other
suitable medium, and by pressure united into very tough pipes of any required
bore or strength, without any stitch or seam, the weakest of which it is said is
capable of bearing a pressure of 600 lbs. per square inch. -
CAPILLARY TUBES, in Physics, are very small pipes, whose canals or
bores are exceedingly narrow, their usual diameter not exceeding one-twentieth
or one-thirtieth of an inch, and in some cases being made so small as to be
scarcely perceptible. One of the most singular phenomena of these tubes is,
that if they are left open at both ends, and one end immersed in water, the
water will rise in the tube to a considerable height above the surface of that
into which they are immersed, the height being inversely as the diameters of
the tubes. Different fluids, however, attain different heights, and quicksilver
does not rise, but, on the contrary, stands higher outside the tube than within.
Various hypotheses have been invented to account for this ascent of fluids: at
the present day it is attributed to a species of attraction, supposed to exist
between the fluid and the tubes, and which is hence denominated capillary
attraction.
CAPSTAN. A machine employed in large vessels, principally for “heaving
up or weighing” the anchor. It consists of a drum or barrel, revolving upon
an upright spindle, and having holes cut in the upper part or drum head, to
receive the ends of a series of horizontal levers, named capstan bars. The cable,
or, in very large vessels, a smaller rope, called the messenger, attached to the
cable, is wound two or three times round the barrel, and as the capstan is turned
round by a portion of the crew distributed at the capstan bars, another portion
of them take in the slack of the cable or messenger, as it is unwound off the
barrel of the capstan. The capstan is superior to the windlass in point of
expedition, owing to the circumstance of the latter requiring the levers to be
shifted into fresh holes four times in each revolution; and more men can also
be employed at the capstan bars than at the hand-spikes of a windlass; but the
men exert their strength more effectually at the windlass than at the capstan,
since in the latter case they are employed to draw horizontally, when they exert
a force of about 35 lbs. only, but at the windlass they may apply their whole
weight at the extremity of the lever, and the average weight of a man is about
150, or more than four times his power of traction. In Hawkes' Patent Capstan,
which we are about to describe, is combined the advantageous action of the wind-
lass, with the continuous movement of the capstan; and the power or velocity
may be varied according to circumstances. The engraving on the next page repre-
sents the patent capstan complete for one deck, a is the drum head of cast iron,
with holes for the insertion of the capstan bars in the ordinary way, if from any
cause that mode of turning the capstan should be preferred; b is the paul head,
round the periphery of which are ranged ten pauls, five of which are in opera-
tion at a time, as that shown at d, the other five are kept turned up in readi-
ness for use when the motion of the capstan is reversed. Each paul has two
clips, which take into two teeth at the same time at every half inch of the
revolution. The inner circle of teeth is for one set of pauls, and the outer
circle for the other set, the notches being in contrary directions; both circles
are inclosed within the paul-rim f. The barrel is composed of a number of
projecting ribs named whelps, having a projection c in the middle, which divides
the barrel into two parts; the upper portion is of a smaller diameter than the
lower, so that by shifting the cable from the lower to the upper part of the
barrel, an increase of power is obtained. In the figure the capstan is repre-
sented divided into six sections; but the number of these sections may be
316 CAPSTAN.
varied according to the size and weight of the capstan; the divisions are made
vertically through the whole length of the capstan, dividing also the whelps,
the plates of which being strongly bolted together, unite it into one firm and
compact body, and admit of its being easily disunited and removed, h is the
central shaft of wrought iron, made square, except at the bearings, which are
properly turned. l l l are three iron standards for supporting the gearing,
which gives motion to the capstan, and may be worked either by means of a
winch or crank, as shown by the dotted lines at m, or by means of capstan
bars, supported horizontally in holes at the circumference of two vertical wheels
* * fixed on the same axle as the crank; the circumference of these wheels
being scored in a proper manner for allowing the bars to be dropped in and
secured by pins, and to be quickly removed at pleasure. The bars when secured
&:
E
sº
Nº.
|-
º,
i
5
|
vº.º.º.
º
ºl. ~...~ : Tº
- *
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in the rims of the wheels n n, form a kind of drum or reel, the men on one side
of which lay hold of the bars and pull upwards, and those on the other side pull
downwards either with their hands, or by stepping on the bars one after another
as they revolve, and thus weigh down. The shaft which carries the wheels n m
bears also two pinions, one of which is shown in gear with the smallest circle
of a double cogged wheel; and on the same shaft as the latter is placed a
pinion, which takes into the circle of cogs fixed on the upper surface of the
paul-head, and causes it to revolve : if the small pinion is brought into gear
with the large wheel, a great addition of power is gained; and according as
the one or the other set of the wheels, and as the larger or smaller of the
barrels of the capstan, are employed, the power admits of several variations to
suit different circumstances.




CARDS. 317
CARABINE, or CARBINE. A fire-arm, something like a sinail musket; it
is usually borne by cavalry soldiers, slung by a belt over the left shoulder.
CARAWAY. A plant much cultivated, particularly in Essex, for its seed,
which is greatly esteemed for its agreeable flavour, pungent warmth, and medi-
cinal properties. By distillation it affords an odoriferous essential oil, which is
much used in white soap, and therewith constitutes the article termed Windsor
SOa,D.
&ARBON. The name given in the modern chemical nomenclature to a
simple combustible, which constitutes a large portion of all animal and vegetable
substances, and which is found in the greatest state of purity in the diamond,
which is composed solely of it. Carbon unites with all the simple combustibles,
and with azote, forming a series of important compounds. From its affinity for
oxygen, it is employed for disoxygenating metallic oxides, and restoring their
bases to a metallic state. With iron it forms steel and plumbago; and with
copper it likewise forms a carburet. In the state in which it is commonly ob-
tained it is termed charcoal, which see.
CARBONATES. Compounds of carbonic acid with salifiable bases com-
posed either of one prime of acid and one of base, or one of acid to two of
base. The former set of compounds are termed carbonates, and the latter bi-
carbonates.
CARBONIC ACID. An acid composed of oxygen and carbon. It abounds
in great quantities in nature, and appears to be produced in a variety of cir-
cumstances. It composes forty-four hundredths of the weight of limestone,
marble, and other natural specimens of calcareous earth, from which it may be
extricated by the simple application of heat, or by the superior affinity of some
other acid, most acids having a stronger action on bodies than this. It is com-
posed of 72 parts of oxygen, and 28 of carbon, and its spec. grav. is 1.5236,
that of atmospheric air being 1:0000. See AERATED WATERs.
CARBONIC OXIDE. A gaseous compound of oxygen and carbon, con-
sisting by weight of 75 of the former, and 100 of the latter. Its spec. grav. is
0.9569. Carbonic oxide may be procured by subjecting to a strong heat in a
retort or gun-barrel, a mixture of an earthy carbonate and metallic filings; the
most convenient mixture is equal parts of dry chalk, and iron or zinc filings; it
is given out also in large quantities from brick kilns, and may be seen burning
with a dark blue flame. It is, when respired, fatal to animal life.
CARBUNCLE. An elegant gem whose colour is deep red, with an ad-
mixture of scarlet. It is usually found pure and faultless, and is of the same
degree of hardness as sapphire. It is naturally of an angular figure, and is
found adhering by its base to a heavy and ferruginous stone of the emery
kind. It bears the fire unaltered; is found only in the East Indies, and there
but rarely.
CARBURETS. Combinations of carbon with any of the simple substances.
CARDS. In the manufactures of cotton and wool, an instrument used for
preparing those substances for being spun into thread, by strengthening the
fibres, and rendering them parallel to each other. They are a species of brush,
composed of wires stuck º strips of leather, and not standing erect, but
inclined to the surface of the leather, and are used by filling the teeth of one
card with the cotton or wool, and drawing another card along in a direction
against the inclination of the teeth, by which means the fibres are drawn out
in a parallel direction, and transferred from the one card to the other. Carding
was originally performed by hand with sheets of cards nailed upon thin boards,
which were drawn against each other. Stock cards were subsequently intro-
duced: in these one card was nailed to an inclined post or bend, and a hand
card drawn over it; but at present the cards are generally arranged upon cylin-
ders, which revolve either against other card cylinders, or against fixed cards.
Cards are fastened upon the cylinders either in parallel strips in the line of the
axis, or they form a continuous spiral band covering the entire surface of the
cylinder. #. the immense number of cards required in cotton mills, the
manufacture is one of great extent and importance, and several very curious
machines have been invented for facilitating the processes, though they have
S S
3.18 CAREPENTRY.
not yet come into common use. In general the leather is pierced by machinery
at the manufacturers', who send it out to the cottagers, together with the wire,
which they cut and bend into form, and afterwards insert in the holes of the
leather. The workman first takes a skein or bundle of wire, consisting of 30
or 40 wires, and placing them against a gauge, cuts the whole at one operation to
the same length, i. means of a strong pair of shears. The wires thus cut are then
placed in another gauge, and a piece of steel, of the same width as the two
legs are to be asunder, is then pressed across the middle of them, and the ends
of the wires, first on one side, and then the other, are turned up against the
sides of the bridge, forming the wire into a staple like this [ ]; they are then
given the knee bend, which brings them into this shape ( (, by an ingenious
machine kept in motion by a weight, like a roasting jack, after which they are
inserted in the leathers by women or children.
CARMINE. A very bright crimson pigment, obtained by precipitating the
colouring matter of cochineal. The Fº is as follows:–Take 4 ounces
of cochineal, finely pulverized, which pour into 4 quarts of rain or distilled
water, boiled previously in a pewter kettle, and boil the whole for six minutes,
adding, during the boiling, 2 drachms of pulverized crystals of tartar. Eight
scruples of Roman alum, in powder, must then be added, and the whole be kept
on the fire one minute longer. As soon as the gross powder has subsided, and
the decoction become clear, decant it into large cylindrical glasses covered over,
and keep it undisturbed till a fine powder is observed to have settled at the
bottom. Then pour off the liquor from this powder, which is to be gradually
dried. From the liquor still coloured, the rest of the colouring matter may be
separated by the solution of tin, when it yields a carmine little inferior to the
former.
CARPENTRY is the art of cutting out, framing, and joining large pieces of
wood to be used in building. The only difference between Carpentry and
Joinery is, that whilst the former includes the larger and rougher description of
work, which is essential to the construction and stability of an edifice, the
latter term comprehends the exterior finishing and ornamental wood-work. To
enter into a detailed account of the numerous tools used in Carpentry, and the
processes of forming, by their application, the almost illimitable variety of
matters that are comprehended in constructive carpentry, would of course
require a volume to itself; and as the subject is foreign to the leading objects of
this work, we shall under this head confine ourselves to some general obser-
vations of a practical nature, alike useful to the engineer as well as the car-
penter. With regard to the tenacity or strength of wood, it has been found by
Muschenbroëk and other eminent experimentalists, first, that the wood which
surrounds immediately the pith or heart of the tree is the weakest, and that this
weakness is greater as the tree is older. It is of importance that this fact be
known, as a common notion exists of a contrary nature. Secondly, the fibres
next to the bark, commonly called the white or blea, are also weaker than the
rest; and the wood gradually increases in strength as it recedes from the centre
to the blea. Thirdly, the wood is stronger in the middle of the trunk than
at the springing of the branches, or at the root; and the wood forming a branch
is weaker than that of the trunk. Fourthly, the wood on the northern sides of
all trees that grow in Europe is the weakest, while that on the south-eastern
side is the strongest; this difference is most remarkable in hedge-row trees, and
such as grow singly. The heart of a tree never lies in its centre, but always
towards its northern side, and the annual coats of wood are thinner on that
side. In conformity with this, it is a general opinion of carpenters that timber
is stronger in proportion to the thickness of its annual plates. The trachea, or
air vessels, being the same in diameter and number of rows in trees of the same
species, occasion the visible separation between the annual plates; for which
ſeason, when these are thicker, they contain a greater portion of the simple
ligneous fibres. Fifthly, all woods are most tenacious whilst green, but after
the trees are felled, that tenacity is considerably diminished by their drying. By
the experiments of Muschenbroek, it appears that the absolute strengths of a
square inch of the following different kinds of wood are as stated
CARPENTRY. 319
Locust . . . . . 20, iOU Pomegranate . . . 9,750
Jujeb . . . . . . . 18,500 Lemon . . . . . 9,250
Beech and Oak . . 17,300 Tamarind . . . . 8,750
Orange . . . . 15,500 Fir . . . . . . . 8,330
Alder . . . . . 13,900 Walnut . . . . 8,130
Elm . . . . . 13,200 Pitch pine . . . . 7,650
Mulberry and Willow 12,500 Quince . . . . . 6,750
Ash . . . . . 12,000 | Cypress . . . . 6,000
Plum . . . . . 11,800 Poplar . . . . , 5,500
Elder . . . . . 10,000 Cedar . . . . . 4,800
The woods mentioned were all formed into slips of uniform dimensions, and
as much cut away from each, as to form a parallelopiped of one-fifth of an inch,
that is, one-twenty-fifth of a square inch in section; and the weights which were
required to tear these asunder, formed the data of the above calculations.
Muschenbroëk gives a very minute detail of his experiments on the ash and
walnut, in which he states the weights required to tear asunder slips taken from
the four sides of these trees, and on each side in a regular progression from the
centre to the circumference. The numbers in the foregoing, corresponding
with these two woods, may be considered, therefore, as the average of more
than fifty trials of each. He mentions, also, that all the other numbers were
calculated with the same care. For these reasons some confidence may be
placed in the results, though they carry the degree of tenacity considerably
higher than those enumerated by some other writers. Pitot and Parent state,
that a weight of 60 lbs. will just tear asunder a square line of sound oak, but
that it will bear 50 lbs. with safety. This gives 8640 for the greatest strength
of a square inch, or rather less than one-half of Muschenbroëk's estimate;
but the latter is, we think, the most entitled to confidence, as the experiments
were made upon greater masses of the material. It should, however, be
observed, that two-thirds of the actual weight which may be sustained by a
body, will greatly impair the strength after a considerable time, and that one-
half the absolute tenacity indicated by experiment, should be the utmost that an
engineer should calculate upon in his constructions. Woods of the same
denomination often differ greatly in their tenacity; those with a very straight
fibre suffer less injury from a load that is insufficient to break them immediately.
Mr. Emerson mentions the following as the loads which may be safely suspended
to an inch square of the several bodies hereafter enumerated; but the term
safely can hardly apply to the four first-named bodies.
Ibs. Ibs.
Iron . . . . . . , 76,400 | Red fir, holly, elder, plane,
Brass . . . . . . . 35,600 and crab . . . . . 5,000
Hempen rope . . . . 19,600 | Cherry and hazel . . . . 4,760
Ivory . . . . . . . 15,700 || Alder, asp, birch, and
Oak, box, and yew . . 7,850 willow . . . . . 4,290
Elm, ash, and beech . . 6,070 | Lead . . . . . . . 450
Walnut and plum . . . 5,360 Freestone . . . . . 914
The same ingenious author has laid down as a practical rule, that a cylinder
of one inch diameter will carry, when loaded to one-fourth of its absolute
strength, as follows:—iron, 135 cwt.; good rope, 22 cwt.; oak, 14 cwt.; and fir,
9 cwt. Parent has shown that the force required to crush a body is nearly
equal to that which will tear it asunder. This may be an approximation to the
truth as respects woods, but it will not apply to any other bodies. Glass, for
instance, will carry a hundred times more on it than oak in this way, but will
not bear suspended above four or five times as much. Oak will suspend a great
deal more than fir, but fir will carry twice as much as a pillar. Some woods
which are very soft, and consequently yield to pressure, possess very strong
fibres, and will resist a longitudinal strain. The softness of texture is chiefly
owing to the crooked nature of their fibres, and to the existence of considerable
vacuities between each fibre, so that they are more easily bent in a lateral
direction and crushed. In all cases where the fibres lie oblique to the strain,
$20 CARRIAGES.
the strength is considerably diminished, which may be ascribed to the circum-
stance, that the parts in such case slide on each other, and the connecting force
of the cementing matter is for that reason easier overcome. The strain which most
commonly acts on materials of any nature, is that which tends to break them in a
transverse direction. For the results derived from experiment in strains of this
nature, we must refer the reader to the article STRENGTH of MATERIALs; but
the complete investigation of the resistance of materials, according to the
direction and situation of the forces applied, would require a volume. The reader
who wishes for full information on this subject, cannot do better than consult
Mr. Barlow's valuable Essay on the Strength and Stress of Timber. Some
excellent practical rules on this important subject will, however, be found in
The New Practical Builder, by Nicholson, and in the works of Banks, Emerson,
and Roberson.
CARPET is a sort of stuff wrought with the needle, or on a loom, and
forms the ordinary furniture of a house, being commonly laid upon the floor.
The Persian and Turkey carpets have hitherto been in the greatest esteem, but
some of the manufacturers of France and Great Britain are making rapid
advances in imitating them, to which they are, in some respects, superior. A
splendid example of this fine spirit of rivalry amongst our own countrymen is
now exhibiting at the Museum of National Manufactures and of the Mechanical
Arts, in Leicester Square, London. The carpet measures 8 yards by 6, and is
called Scoto-Persian by the manufacturers, Messrs. Deans, of Stewarton, in
Ayrshire. In the usual mode of weaving carpets, the design or pattern is traced
in its proper colours on cartoons, tied before the workman, who looks at them
every moment, because every stitch is marked upon them as it is to be in his
work. By this means he always knows what colours and shades he is to use,
and how many stitches of the same colour. In this he is assisted by squares,
into which the whole design is divided; each square is divided into ten vertical
lines, corresponding with the parcels of ten threads of the warp; and besides,
each square is ruled with ten horizontal lines crossing the vertical lines at right
angles. The workman having placed his spindles of thread near him, begins
to work on the first horizontal line of one of the squares. The lines marked
in the cartoon are not traced on the warp, because an iron wire, which is longer
than the width of a parcel of ten threads, supplies the place of a cross line.
This wire is managed by a crook at one end, at the workman's right hand;
towards the other end it is flatted into a sort of knife with a back and edge, and
grows wider at the point. . The weaver fixes his wire horizontally on the warp,
by twisting some turns of a suitable thread of the woof around it, which he
passes forward and backward behind a fore thread of the warp, and then behind
the opposite thread, drawing them in their turn by their leashes. Afterwards,
he brings the woof-thread round the wire in order to begin again to thrust it
into the warp. He continues in this manner to cover the iron rod or wire, and
to fill up a line to the tenth thread of the warp. He is at liberty either to stop
here, or to go on with the same cross line in the next division, according as he
passes the thread of the woof round the iron wire, and into the warp, the threads
of which he causes to cross one another at every instant; when he comes to
the end of the line he takes care to strike in the woof he has used. This row
of stitches is again closed and levelled, and in the same manner the weaver
proceeds; then with his left hand he lays a strong pair of shears along the
finished line, cuts off the loose hairs, and thus forms a row of tufts perfectly
even, which, together with those before and after it, form the shag. Thus the
workman follows, stitch for stitch and colour for colour, the plan of his pattern,
which he is attempting to imitate; and he paints magnificently without having
he least notion of painting or drawing.
CARRIAGE. A vehicle for the transport of persons and goods by land,
Although the varieties of carriages are very great, yet they may be ranged
under two heads, viz. sledges, or carriages without wheels, and wheeled carriages.
The earliest carriages were doubtless of the first class, or without wheels; and
although they are now very generally superseded by carriages mounted upon
wheels, and indeed have become nearly obsolete in this country yet they are
CARRIAGES. 321
still extensively used in the more northern parts of Europe, where the ground
is for a considerable portion of the year covered with snow, and the rivers frozen
over so as to allow carriages to travel upon them. In these cases sledges are
found superior to wheel carriages, as the friction upon the surface of the snow
or ice is small, and as, from the greater extent of bearing surface, they do not sink
so deep as wheel carriages, in which the whole weight presses upon two, or at
most, four points. The motion is also found to be much more easy, as from
their length of bearing they do not rise and fall with every slight inequality in
the roads, in the manner of wheel carriages. But for general purposes, and on
roads composed of rough materials, which offer great resistance to bodies sliding
over them, it is found highly advantageous to place the carriages upon wheels,
as by this means the sliding motion is converted into a rolling motion, and the
rubbing surfaces, when the friction takes place, are reduced in the proportion of
the diameter of the wheel to that of its axle, and the friction is still further
reduced by the rubbing surfaces being polished, and admitting of lubrication,
which tends materially to diminish friction. The friction being diminished in
proportion to the difference between the diameters of the wheels and the axles,
it is evidently advantageous to employ wheels of large diameter, which are also
beneficial in another respect, as they experience less resistance from the in-
equalities of the surface over which they roll, as the leverage to which the
power of the horse is applied, is as the diameter of the wheel; and as any
obstacle on a road will sooner come in contact with a large wheel than with
a small one, in consequence of the curvature of the former being flatter than
that of the latter, so the power by which the wheel is drawn over the obstacle
is exerted through a greater space with the large than with the small one.
We shall endeavour further to explain this by a little diagram. Let the
circle a represent a small wheel,
whose axle is at b, and c a stone
lying in the road, over which the ...~... **
wheel is to pass; and the dotted ...” *..
circle to represent a large wheel, .." *.
whose centre is at f ; now the Ž %
obstacle k is already in contact with ; \
the large wheel, but the small wheel
has not yet arrived at it: the horse
would therefore move through a
greater space in bringing the centre
of the large wheel perpendicularly
over the obstacle, than in bringing
the centre of the small wheel over the
object after it had come in contact
with the periphery; thus the horse
exerts more power, or what is the same, exerts the same power through a
greater space with the large wheel than with the small one. And again, as
the angle k f h, at which the obstacle k interrupts the large wheel, is the same
as the angle c b d, at which the obstacle c interrupts the small wheel, the same
force which will draw the small wheel over the obstacle c, will, by the increased
leverage, draw the large wheel over the obstacle k. The advantages above attri-
buted to large wheels over small ones are not merely theoretical, but have been
confirmed in a variety of instances in practice. We therefore insert the diagram
on the following page, exhibiting a method of applying hind wheels of iarger
diameter than ordinary to waggons, without carrying the floor higher than usual.
a a represents the hind wheels; b b the bended axletree, of a crank form, passing
under the bed of the carriage, which lies between the two extremities of the
axletree, and permits the floor of the carriage to lie close to the upper side of the
axletree, the floor being usually as much above the latter as the thickness or
depth of the bed. The modes by which carriages are or have been propelled are
various—as the force of animals, of wind, of men, exerted upon machinery con-
tained within the carriage, and that of steam. Carriages propelled by wind
acting upon sails are not common for land travelling, although such have been
-
|

322 CARRIAGES,
constructed; but in some parts of Holland, boats mounted upon long skids
are frequently employed for sailing over the ice, and have sometimes been known
O E- . º W-l O
2-TE=-\}<=
O
0) <=> — =
*cº 3 *EF
| l
I 2.
ſ I
4 3. 6
T
f
#
to go at the rate of eighteen miles per hour. In 1826 a patent was obtained
by Col. Viney and G. Pocock, for a carriage, to be impelled by the force of the
wind acting upon one or more kites attached to the carriage, which they de-
nominated the “Charvolant.” It is represented in Fig. 2 in the engraving on the
following page. The kite, a, Fig. 1, is jointed in the middle, that it may be folded
up, and carried or stowed away with greater facility, b b b b are four cords for
regulating the position of the kite, and to assist the steerage; they are brought
together by passing through the dead eye c, whence they proceed to the carriage,
where they are regulated to the proper lengths by the persons therein. By
shortening the cords on the right-hand side of the kite, the car may be turned
to the right, and by shortening the left-hand cords it will be turned to the left.
But the charvolant, by the cross handle e and stem ef, which acts on the axis
of the fore wheels by means of an endless band or cord passing about a pulley
f fixed on the lower end of the stem ef, and the pulley g fixed on to the bed of
the axletree of the fore wheels. The machine is stopped, or its motion re-
tarded by the drag k, which is attached to the perch by a spring to keep it
off the ground till it is required to retard the motion or to stop the carriage,
when the fluke end is pressed into the earth by the lever h acting on the
connecting piece i. The patentees several times exhibited a carriage similar
to the above, in Hyde Park, and, we believe, performed a journey from South-
ampton to London with it, but we do not recollect the particulars. The scheme
is not altogether original. Dr. Franklin employed kites to assist swimmers,
and was of opinion that with such aid a man might swim across the Channel
from Dover to Calais. Attempts have also been made before the present to
move both boats and cars by the same means; but we believe the present is
the first attempt to trim or regulate the position of the kite according to the
direction in which the carriage is to move. -



CARRIAGES. 323
Fig. 2.
In no class of carriages does this country so much excel all other nations as
in the stage coaches, which, for beauty, compactness, lightness, strength, and
easy draught, are far superior to the public vehicles of any other country. In
a nation so eminently commercial, where dispatch and punctuality are of the
first necessity in conducting all transactions, every thing which tends to
advance the means of communication becomes an object of consideration ;
and numerous improvements have of late years therefore been introduced in the
structure and arrangement of our stage coaches. The engraving in the following
page represents a model of an improved stage coach, by Mr. Skinner, for which
he was presented with the sum of thirty guineas by the Society of Arts. The
lowering of the centre of gravity, by removing the heavy luggage and outside
passengers from the roof of the carriage; the convenient accommodation of the
latter; the adoption of high fore-wheels to ease the draught; and several minor
conveniences; will be found to have been duly attended to, and to be combined
in the model of which the following is a description. The engraving gives a
perspective view of the vehicle. The front wheels are 5 feet 9 inches in
diameter. The inside and outside passengers are seated on the same level, the
floor being as near to the axletree as the play of the springs will admit, a is
the door through which the hind passengers get up, the seats being situated as
shown at b ; c is a seat for the guard, attached to the door a y dd iron bars
attached to the top and bottom of the door, and projecting enough to be firmly
held by turn buckles e e : the steps g h and i, serve for the front passengers and
coachman to ascend by ; the passengers step upon the boards jj on either side,
and over the side rails into the compartment k; the steps l m n 0 serve for
ascending the hind part of the coach; pp boards on each side over the hind
wheels; there are similar ones jj over the front wheels, which have iron rails


324 CARRIAGES.
to hold small luggage. To allow of locking the front wheels, the floor is nar-
rowed in the manner delineated; q is the hind boot; r r the front boot; s boxes
opening in the floor of the coach; t and v boxes opening in the guard's seat; u
a roll of leather to cover the front passengers; it has a slip of iron along its
209"
– Eji=1
front, which catches on to the hooks w w ; it is wound up and held tight by a
ratchet wheel and pall a ; y the locking pin, which plays through the axletree;
the locking plate is under the floor and above the springs. There are five springs
in front, and five at the back; two across each axletree, four across the coach
answering to them, and two more, one over each axletree, and rubbing on them.
The following engraving represents a stage coach of a very novel appearance,
invented by Mr. P. Birt, of the Strand, and distinguished by an improved
method of yoking the horses, and also by a drag which can be put into action
at pleasure, without any person descending for that purpose. The inside pas-
sengers occupy the seats at in s, which are at a higher level than those for the
ºº::
sº-sºº
outside passengers at o u t. There are three doors, one opening into the inside,
behind the seat n, and two opening into the outside at did. The receptacle for
the luggage is at the bottom ce; f is the coachman's seat, where he is provided
with the means of putting the drag in action at pleasure, by means of the


CARRiAGES. 325
lever g, the extremity of which is connected by a rope or chain to the skid iron,
and the latter is supported by a spring arm j, which is fixed to the axletree or
the hind wheels. The usual method of yoking the horses to a coach, is to
attach the two ends of the traces to two fixed points on the long front splinter-
Fig. 3. —ºr Fig. 2.
bar. In this way, if the traces are not exactly of a length, the horse pulls only
on one side when going in a straight line, and invariably so when making a
curve in the road; the traces are, in consequence, subject to double the strain,
and the horses have all the work thrown upon one shoulder, instead of it being
equalized on both. To remedy this disadvantage Mr. Birt fixes two bent elastic
pieces to the splinter-bar, as shown in Fig. 3, which turn upon central pivots;
and the traces being attached to the extremities of these elastic bars, the pull is
made from a single point, like that of the leaders in a four-horsed coach. The
advantage derived from this alteration is, greater freedom to the action of the
horses, and a better direction of their power; the elastic bars likewise prevent
a great deal of unpleasant jolting, usually communicated to the carriage by the
motion of the horses.
The annexed engraving represents a four-wheeled carriage, invented by Mr.
Fig. 1.
- ºl
g-
º
E
gº-
E-
sº


326 CARRIAGES.
Fuller, of Bath, so constructed as to prevent the upsetting by those irregula-
rities in the road which are sufficient to overturn carriages of the usual construc-
tion, and, at the same time, to lessen considerably the unpleasant jolting motion
arising from the same cause. . The construction may be described as follows:—
Immediately over the axles of the fore wheels is placed a bar cc (which the in-
ventor calls the bed of the axle); this bar is attached to the axle by the springs
Fig. 2. H
g |
* || ETEEIºTTET || 3
<-E-
- *
hh. On this bar is placed the locking wheel a a, which turns on the pivot b,
and is supported on the bar and frame-work as shown in Fig. 2. To the
locking wheel is firmly fixed the horizontal bar dd, at right angles to the axle-
bed, when the carriage is going straight forward. The ends of this cross-bar
are turned and fitted into the plummer block c c, which are attached by means
of the connecting pieces ff and g g, to the fore part of the carriage as repre-
sented in Fig. 1. This permits the axle of the fore wheels, with the locking
wheel, to take an inclined position, while the body of the carriage remains
level; and it will be seen from the carriage represented in Fig. 1, (which is a
front view,) that the axle of the fore wheels p q, with the locking wheel and its
attachments, is inclined considerably by the wheel q passing over an elevation
in the road, while the body of the carriage remains horizontal, and its weight
is equally supported by both the wheels, instead of being all thrown on the
lower wheel, as would be the case were it not permitted to turn on the pivots of
the bar d. The other parts of the carriage are not different from those in
common use, and therefore need not be particularly described. o 0 are the
hind wheels; l l part of the seats; k the dashing-iron and leather, and m the
foot-board.
The engraving on the following page represents a method offirmly fixing the poles
to carriages, and, when required, of readily releasing them, great inconvenience
being frequently experienced from the poles sticking fast in wet weather when
fitted on the common plan, and being also subject to premature destruction in
those parts. a is the pole of the carriage; b the splinter bar; c c the fetchels;
d part of the wooden axletree. An iron frame e e is fixed between the fetchels;
in the front of this iron frame there is a proper aperture to receive the tapered
part of the carriage pole, and another at the back, of less dimensions, to receive
the extreme end, which is shod with an iron bolt for that purpose; this bolt or
pin is fixed on to the extremity of the pole by two long straps, which clasp the






CARRIAGES. 327
top and the bottom, aid have bolis passing through both. When tile poie is
inserted into its place, it is secured there by turning the screw f, which forces
two iron wedges into recesses made in the frame, from whence they cannot be
withdrawn, or the pole detached, but by turning the pole the reverse way.
A patent was obtained in 1825 by Mr. Corbet, of Glasgow, for an improve-
ment upon the steps of carriages; which is applicable to coaches generally, but
is peculiarly adapted to such, the proprietors of which do not employ a footman
Fig. 2. -
§
§ N sº w
-*-* * *-T-T-T-F. E. E.E.T.: "
* * * * * * x N.N. Y.
}-
\*
.p.
*** *
º
to open and shut the door and steps, as the act of opening the door causes the
steps to open out, and that of shutting it shuts the steps up again. For
this reason the invention may be found of great convenience to medical and
other professional gentlemen. In the above engraving, Fig. 1 is intended to













328 CARTRIDGE.
represent the back view of a coach, on one side of which the steps and door
are both open, and on the other side are both shut. Fig. 2 gives a side view of
the steps, only on a larger scale, and will, we trust, enable the reader to under-
stand their construction. At a is the coach body; b a part of the coach door
open ; c is a bent iron fixed to the bottom of the door, connected to a curved
rod d, at the extremity of which is a joint e attaching it to the lever f which
moves upon a fulcrum in the middle; at g is another joint, by which and an
intermediate rod it is attached to one of the horns of the crank h; the other
horn of this crank is connected by a joint to the long curved lever i i, which
gives motion to the short levers k k, and these last being in one piece with the
steps ll, they move together. The long curved bar o, (of which there are two,
one on each side of the steps,) and its short branch n are fixtures, being bolted
to the body of the carriage p p. The reader having noticed the train and con-
nexion of the levers just mentioned, will readily perceive that the act of
shutting the door of the carriage will cause the lever f to assume another angle,
by which the crank h, and consequently the bar i i, will be thrown into the
position shown by the dotted lines; and that it necessarily follows the steps will
be forced into the situation shown by the dotted lines at ll.
CARNELIAN is a sub-species of calcedony. Its colours are white
yellow, brown, and red. It has a conchoidal fracture, and a spec. grav. of 2.6.
It is semi-transparent, and has a glistening lustre. It is found in the chan-
nels of torrents in India, in nodules of a blackish olive, passing into grey.
After exposure for some weeks to the sun, they are subjected to heat in
earthen pots, whence proceed the lively colours for which they are valued in
jewellery.
CARRONADE. A short piece of ordnance, intended principally for close
combat as sea.
CARTHAMUS, SAFFLower, or BASTARD SAFFRON. Watery menstrua
take up the yellow, and leave the red colour, which may afterwards be extracted
by alcohol, or by a weak solution of alkali; such particularly are the saffron
coloured flowers of carthamus. These, after the yellow matter has been ex-
tracted by water, are said to give a tincture to ley, from which, on standing at
rest for some time, a deep red fecula subsides, called safflower; and from the
countries whence it is commonly brought to us, Spanish red and China lake.
The pigment impregnates alcohol with a beautiful red tincture, but communi-
cates no colour to water. Rouge is prepared from carthamus. For this purpose
the red colour is extracted by a solution of the sub-carbonate of soda, and pre-
cipitated by lemon juice, previously depurated by standing. This precipitate
is dried on earthen plates, mixed with French chalk, reduced to a powder by
means of the leaves of shave grass, triturated with it till they are both very
fine, and then sifted. The fineness of the powder, and proportion of the pre-
cipitate, constitute the difference between the finer and the cheaper rouge. It
is likewise spread very thin upon saucers, and sold in that state for dying.
Carthamus is used for dying silk of a poppy, cherry, rose, or bright
orange red.
CARTOON, or CART.on. A design drawn on strong paper, to be afterwards
chalked through, and transferred on the fresh plaster of a wall, to be painted
in fresco. It is also used for a design coloured for working mosaic tapestry,
carpets, &c. The word is from the Italian, cartoni, large paper, denoting many
sheets of paper pasted on canvass, on which large designs are made, whether
coloured or with chalks only. The most celebrated performances of this kind
are those by Raphael.
CARTOUCHE is a general term in the military art, applicable to a variety
of projectiles contained in differently formed cases.
CARTRIDGE. A case containing a charge of powder for fire-arms. For
pistols and muskets the case is made of strong paper manufactured for the pur-
pose, and called therefore cartridge-paper, and the cartridges are called ball
or blank cartridges, accordingly as they contain or not a ball or bullet, with the
powder in the case. For cannon, the case for the powder is made of serge or
flannel; but the Americans, during the last war, are said to have employed for
CARWING. 329
that purpose “fea-lead,” similar to that used for lining tea-chests; the advantage
of which is, that the guns do not require sponging, and that no ignited portions
of the cartridge can remain in the chamber, from which most dreadful accidents
sometimes happen. For cannon, the cartridges are always made up without the
shot, between which and the cartridge, a
wad made of old rope is placed in charging
the cannon. The annexed engraving re-
presents an ingenious and well-contrived
machine, invented by W. Caffin, Esq., of
Woolwich, for filling cartridges, but which,
if constructed on a larger scale, may be
applied to measure grain, seed, and all Fig.
other articles that are estimated by strike
measure. Fig. 1 represents a perspective
view of the instrument, and Fig. 2 an
elevation in section. The measures d d
are fixed vertically in a circular plate f
opposite to each other, with an axis be-
tween them, upon which they work be-
tween two other plates. On the top plate
3) y a hopper w is fixed, communicating
alternately with the measures, and filling
hem; and on the opposite side, in the
bottom plate a, is a hole with a spout 2,
through which the discharge takes place.
The plates are framed together by three
pillars b b b, having double adjusting nuts
c c on each to regulate the distance of the
plates. The measures are moved by a
handle or lever e, the motion of which is
limited by two pins g g, which, while it
presents one under the hopper to receive,
places the other immediately over the
discharge hole for delivery, so that the
two operations of filling and discharging,
are going on at the same time. The bot-
tom of each measure is contracted, to re-
tard, in a small degree, the discharge, so Fig. 2.
as to secure one measure being filled be- yes
fore the other is emptied. A hole is cut . . . .
in the top plate over the discharging
measure, by which it may be ascertained *||a
that it is always perfectly filled, as well
as that the whole of its contents are de-
livered; a is the hook by which the e
machine is supported. Some of these
machines have been used a long time for 2 \º
filling cartridges, and a boy delivers with s
ease 12,500 measures daily, from one ma- #
chine, in the most perfect and accurate
manner, and supplies his hopper himself.
CARVING, in a general sense, is the art of cutting or fashioning a hard
body by means of some sharp instrument; but in a more particular sense it is
usually understood to be the art of cutting figures and designs in wood.
A carver should possess some knowledge of drawing and modelling, in order
that he may be able to copy from nature. A rough imitation of the object or
design should first be modelled in clay by the fingers, and afterwards completed
with the modelling tools. A mould is then to be made, and a cast taken from
the model in plaster of Paris, as clay is difficult to preserve unless baked in a
kiln. The mould is made in the following manner?—Plaster of Paris, which
E



330 CASTING.
easily mixes with water, should be made of the thickness of cream, and should
be spread all over the model. When the plaster is set, the model should be
removed, the clay carefully picked out, and a mould will be obtained, called a
waste mould, which must be left in cold water for a quarter of an hour. When
used as a cast, it should be rubbed over with a mixture of hog's lard and the
droppings of sweet oil. The plaster of Paris is to be mixed as before, and
poured into the mould, which afterwards should be knocked off with a chisel and
mallet, by small pieces at a time; the design will then appear of the same form
as that modelled in clay, which the carver may proceed to copy in any sort of
wood, but lime-tree is the best suited to beginners. The tools used in carving
are of various forms and sizes, and may be procured of good quality in the
shops, ready made. The instruments used by sculptors for measuring the dif-
ferent parts of their work, particularly the heights and depths, may be very
advantageously employed by the carver. Carving is an extremely fascinating
employment, and the young artist of taste soon becomes astonished and
delighted with the effect he produces by a few cuts of his chisel,
CASCABEL. The knot of metal behind the breech of a cannon; it serves
as a handle to elevate or direct the piece, and likewise to sling and
fasten it. -
CASCADE. . A steep fall of water from a higher to a lower place: cascades
are both natural and artificial; those which fall with great noise are usually
called cataracts, which see; also Fount AIN.
CASE. In printing, a large oblong frame, placed aslope, divided into several
little square compartments, in each of which are kept a quantity of type or
letters of the same kind, whence the compositor takes them as he requires them
to compose his matter.
CASE-HARDENING is a term applied to the process of converting the
external surface of articles or masses of iron into steel, with the view of com-
bining the hardness of the latter with the toughness and comparative cheapness
of the former. See IRoN.
CASEMATES. Vaulted apartments of masonry made in the bastions of
fortifications. -
CASEMENT. A small window made to open or turn upon hinges.
CASERNS. A term frequently used synonymously with barracks, but which
more strictly applies to the huts or lodgings of soldiers in the ramparts of for-
tified places. -
CASE SHOT, or CANISTER SHoT. Tin canisters filled with small balls,
which are discharged from cannon, and make sad havock with human life.
CASHEW-NUT. See ANACARDIUM.
CASK. A vessel of capacity, for holding both liquid and dry goods. See
BARREL and Cooper ING.
CASTING AND Moulding. Under this head we shall give the art of taking
impressions from sculptures, medals, and other delicate works of art; also the
taking of casts from the face, and other natural objects. For the process of
casting articles of metal in the large way, see FoundRY. To procure a cast
from any figure, bust, medal, &c. it is necessary to obtain a mould, by pressing
upon the thing to be copied some substance capable of being forced into all the
cavities or hollows of the sculpture. When this mould is dry and hard, some
substance, which will fill all the cavities of the mould, is poured into it: the
form of the original from which the mould was taken, is now accurately repre-
sented. Moulding in any particular manner depends upon the form of the
subject. When there are no projecting parts, but such as rectilineal angles
with the principal surface of the body, nothing more is necessary than to cover
it over with the substance of which the mould is to be formed, and to take it off
clean, and without bending. It may be laid horizontally, and will bear to be
oiled without injury. The substances used for moulding are various, according
to the nature and the situation of the sculpture; as wax, metal, plaster of
Paris, &c. This last is prepared in a fine powder, mixed with water, and
poured over the mould to a convenient thickness, after oiling it to prevent the
plaster from sticking. A composition of bees' wax, resin, and pitch, makes a
CASTING. - 331
very desirable mould, if many casts are to be taken. If the situation of the
sculpture be perpendicular, clay, or some similar substance, must be used. The
best kind of clay is that with which sculptors make their models; it is worked
to a due consistence, and having been spread out to a size sufficient to cover all
the surface, it is sprinkled over with whiting, to prevent it from adhering to the
original. Bees' wax and dough, or the crumb of new bread, may also be used
for moulding some small subjects, as impressions of seals and bijoux. When
there are under-cuttings in the bas relief, they must be first filled up before it
can be moulded, otherwise the mould could not be got off. When the casts are
taken afterwards, the places must be worked out with a proper tool. When the
model or original subject is of a round form, or projects so much that it cannot
be moulded in this manner, the mould must be divided into several parts; and
it is frequently necessary to cast each of them separately, and afterwards to join
them together. In this case the plaster must be tempered with water to such a
consistence that it may be worked like soft paste, and laid on with some con-
venient instrument, compressing it till it adapt itself to all parts of the surface.
When the model is thus covered to a convenient thickness, the whole is left at
rest till it becomes sufficiently firm to bear dividing, without falling to pieces
by any slight violence; it must then be separated into pieces to be taken from
the model, which is done by cutting it with a thin bladed knife. Being now
divided, it must be cautiously taken off and kept till dry; but before the separa-
tion of the parts is made, they are notched across the joints at proper distances,
that they may with certainty be put together again. The art of properly
dividing the moulds to make them separate from the model, requires dexterity
and skill. Where the subject is of a round or spheroidal form, it is best to
separate the mould into three parts, which will then easily come off from the
model; and the same will hold good of a cylinder, or any regular curved
figure. The mould being thus formed and dry, and the parts put together, it
must be first oiled and placed in such a position that the hollow may be
upwards. It is then filled with plaster mixed with water, and repaired where
necessary. This finishes the operation. In larger masses, where there would
otherwise be a great thickness of the plaster, a core may be put within the
mould, as was observed in regard to the casting of statues, to produce a hollow
in the cast: this saves expense of plaster, and renders the cast lighter. In the
same manner, figures, busts, &c., may be cast of lead, or any other metal, in
the moulds of plaster or clay; the moulds must be perfectly dry, for should
there be any moisture, the sudden heat of the metal will convert it into vapour,
and produce by its expansion an explosion that would blow the melted metal
about to the great danger of the artist.
To take a Cast in Metal from any small Animal, Insect, or Vegetable. Prepare
a box sufficiently large to hold the animal, in which it must be suspended by a
string; the legs, wings, &c. of the animal, or the tendrils, leaves, &c. of the
vegetable, must be separated and adjusted in their right position by a pair of
pincers. A due quantity of plaster of Paris, mixed with talc, must be tem-
pered to a proper consistence with water, and the sides of the box oiled. Also
a straight piece of stick must be put to the principal part of the body, and
pieces of wire to the extremities of the other parts, that they may form, when
drawn out after the matter of the mould is set and firm, proper channels for
pouring in the metal, and vents for the air, which, otherwise, by the rarefac-
tion it would undergo, from the heat of the metal, would blow it out, or
burst the mould. In a short time the plaster will set and become hard ; the
stick and wires may now be drawn out, and the frame in which the mould was
cast taken away; the mould must then be put, first into a moderate heat,
and afterwards, when it is as dry as it can be rendered by that degree, removed
into a greater, which may be gradually increased until the whole be red hot.
The animal or vegetable inclosed in the mould will then be burnt to a coal,
and may be totally calcined to ashes by blowing for some time into the charcoal
and passages made for pouring in the metal and giving vent to the air. This
operation, at the same time that it destroys the remainder of the animal or vegetable
matter, will force out the ashes. The mould is then allowed to cool gently; the
332 CASTING.
destruction of the substance that had been included in it has now produced a cor-
responding hollow; but it may, nevertheless, be proper to shake the mould,
and blow with bellows into each of the air vents, to free it wholly from any
remaining ashes: when there may be an opportunity of filling the hollow with
quicksilver, it will be found an effectual method of cleaning the cavity, as all
the dust and ashes must rise to the surface of the quicksilver, and be poured
out with it. The mould being thus prepared, must be heated very hot when
used, if the cast is to be made of copper or brass, but a less degree of heat will
serve for lead and tin. The metal being poured into the mould, it must
be gently struck, and then suffered to rest till it be cold; it is then carefully
taken from the cast, but without force : such parts of the matter as appear to ad-
here more strongly, are to be softened by soaking in water until they be loosened,
that none of the more delicate parts of the cast may be broken off or bent.
When talc cannot be obtained, plaster alone may be used; it is apt, however,
to be calcined by the heat used in burning the animal or vegetable from which
the cast is taken, and to become of too incoherent and fusible a texture. Stour-
bridge clay, washed perfectly fine, and mixed with an equal part of fine sand,
may be employed. Pounded pumice-stone and plaster of Paris, in equal
quantities, mixed with washed clay in the same proportion, make excellent
moulds.
To take a Cast in Plaster from a Person's Face. The person from whom the
cast is to be taken should lay down on his back, with his hair tied back, so that
none may cover his face. Into each nostril a conical piece of stiff paper, open
at each end, is placed to allow of breathing. The face is then to be lightly oiled
over with salad oil, to prevent the plaster from sticking to the skin, Fresh burnt
plaster is mixed with water to a proper consistence, and poured in spoonsful all
over the face (taking care that the eyes be shut), till it is entirely covered to
the thickness of a quarter of an inch. This substance will grow sensibly hot,
but this inconvenience is of short duration as, in a few minutes, the plaster
will set hard, and may be taken off in a complete mask, which will form a
mould, in which a head of clay may be moulded, wherein the eyes may be
represented as open, and such other additions or corrections made as may be
found necessary. Then this second face being anointed with oil, a second
mould of plaster is made upon it, consisting of two parts, jointed lengthwise
along the ridge of the noise, and in this a cast in plaster is taken, which is an
exact likeness of the original. -
To take Casts from Medals, a mould must first be made of plaster of Paris,
or of melted sulphur. After having oiled the surface of the medal with a little
cotton, or a camel's hair pencil dipped in oil of olives, a hoop of paper must be
put round the medal, standing up above the surface, of the thickness you wish
the mould to be. Take now some plaster of Paris, mix it with water to the
consistence of cream, and with a brush rub it over the surface of the medal, to
prevent air-holes from appearing; then immediately afterwards make it to a
sufficient thickness by pouring in more plaster. , Let it stand half an hour,
when it will have grown so hard that you may take it off; then pare it smooth
on the back and round the edges, neatly: in cold or damp weather it should be
dried before a fire. When the mould is large, if you cover its face with fine
plaster, a coarse sort will do for the back; but no more plaster should be
mixed up at one time than can be used, as it will soon get hard, and cannot be
softened without being burned over again. Sulphur must not be poured upon
silver medals, as this will tarnish them. To prepare your mould for casting
sulphur, put plaster of Paris in it; take half a pint of boiled linseed oil, and one
ounce of oil of turpentine, and mix them together in a bottle, dip the surface
of the mould into this mixture, take the mould out again, and when it has ab-
sorbed the oil, dip it again; repeat this till the oil will no longer be absorbed.
Then wipe off the oil with cotton wool, and set the mould in a dry place for a
day or two, when it will be a hard surface. To cast plaster of Paris in this
mould, proceed with it in the same manner as above directed for obtaining the
mould itself, first oiling the mould with olive oil. When casts are wanted in
sulphur, the material must be melted in an iron ladle
CATOPTRICS. 333
To take Casis with Isinglass. Dissolve isinglass with water over the fire. With
a hair pencil lay the solution carefully over the surface of the medal, and let it
dry. When hard, raise the isinglass with the point of a knife, and it will fly
off with a spring, leaving a sharp impression of the medal. The isinglass may be
coloured with any of the water colours while in solution, or you may breathe
on the concave side, and lay gold leaf upon it, which, by shining through,
will give it the appearance of a gold medal. A little carmine mixed with the
isinglass gives the appearance of copper, particularly if gold leaf be placed inside.
CASTORS. Small wheels fixed to heavy household furniture, as tables,
sofas, &c. to admit of moving them with facility. The annexed engraving
represents an improvement upon the common con-
struction, by the introduction of small antifriction
rollers, by which means the strain and pressure
upon the central pin is removed, and the small
wheel readily assumes the proper direction. It
is the invention of Mr. Harcourt, of Birming-
ham. Fig. 1 is a side view of the castor, the
upper or socket part only being in section; a a
is a guide plate fixed round the central pin so
as to revolve with it : this plate has circular
holes made through it, in each of which is a
little spherical ball, which rolls as it is car-
ried round with the plate. Fig. 2 gives the plan
of the guide plate a, which has three or more
apertures for the antifriction rollers, and these
rollers may be either spherical or cylindrical;
for which reason two of them are shown in this
diagram as spherical, and one as cylindrical.
CATARACT, in hydrography, is occasioned
by a precipice in the channel of a river, caused
by rocks or other obstacles stopping the course
of the stream, from whence the water falls with
great noise and rapidity. Such are the cataracts
of the Nile, the Danube, the Rhine, &c. In
that of Niagara, the perpendicular fall of the
water is 137 feet, and in that of Pistell Rhaiadr,
in North Wales, the fall of water is nearly 240
feet from the mountain to the lower pool.
CATECHU, or JAPAN EARTH. An extract prepared in India from the juice
of the mimosa catechu. In its present state it is a dry pulverable substance,
outwardly of a reddish colour, and internally of a shining dark brown, tinged
with a reddish hue. It contains a greater portion of tannin than any other
vegetable matter, and what is very remarkable, no gallic acid.
CATENARIA, or CATENARY. In the higher geometry, the curve line
formed by a line or cord hanging freely between two points of suspension,
whether those points be horizontal or not. The properties of this curve have
been practically applied in the construction of suspension bridges, for a descrip-
tion of which see BRIDGEs.
CATOPTRICS, is that part of science which treats of the laws and properties
of light reflected from mirrors or specula. The whole doctrine of catoptrics
depends on this simple principle, namely, that the angle of incidence is equal
to the angle of reflection.
CATopTRIC CISTULA. An arrangement of mirrors in a kind of box, by
which objects are represented as multiplied, magnified, or deformed. A variety
of pleasing phenomena are exhibited by machines of this kind.
Catoptric, or REFLECTING DIAL, is a kind of dial which shows the hours
by means of a piece of looking-glass plate, adjusted to reflect the solar rays
upwards to the ceiling of a room, on which the hour lines are delineated.
CATopTR1c TELEscope. Instead of lenses, this telescope is furnished chiefly
with mirrors, and exhibits remote objects by reflection instead of refraction.
U U

334 CEMENTS.
CAT'S EYE. A mineral of a beautiful appearance, brought from Ceylon.
Its colours are grey, green, brown, and red, of various shades; and from a
peculiar play of light proceeding from interposed white fibres, it has derived its
name. It is valued for setting as a precious stone.
CAULKING is a term applied in ship-building to the driving of a quantity
of oakum, saturated with tar, into the seams between the planks of ships,
which is effected by a blunt chisel and a mallet. After the oakum has been
driven very hard into the seams, it is covered with hot melted pitch or resin, to
preserve it against the effects of the water. The term caulking is, however, now
extensively applied to other operations of a similar nature; thus engineers in
closing up the junctures between the flanges of pipes or plates of iron, caulk
them with iron cement.
CAUSTIC. A term in chemistry, applied to alkalies when deprived of
carbonic acid by means of quick lime.
CAUSTIc (Lunar). A preparation of silver dissolved in nitrous acid, and
afterwards fused and formed into small cylindrical pieces in a mould.
CAWK. A term given by miners to the opaque sulphate of barytes.
CEMENTATION. A chemical process, which consists in surrounding a
body in the solid state with the powder of some other bodies, and exposing the
whole for a time to a degree of heat not sufficient to fuse the contents. Thus
iron is eonverted into steel by powdered charcoal ; green bottle glass into
porcelain, by sand, &c.
CEMENTS, in general, are substances employed to unite bodies in close
adhesion, for which purpose they are applied in a semi-fluid or pasty state,
so as to be brought into intimate contact with the opposite surfaces, and becoming
solid as the moisture exhales, the whole form, as it were, one mass. Cements
are variously composed, according to the nature of the surfaces to which they
are applied, and their exposure to heat or moisture. We shall here annex the
processes of preparing and mode of employing those which are in the most
esteem.
Cement for Steam. The following methods are adopted by machinists to
join the flanges of iron cylinders, and other parts of hydraulic and steam
engines. Boiled linseed oil, litharge, red and white lead, mixed together to a
proper consistence, applied on each side of a piece of flannel, previously shaped
to fit the joint, and then interposed between the pieces before they are brought
home, as the workmen term it, to their place, by the screws or other fastenings
employed, make a close and durable joint. The quantities of the ingredients
may be varied without inconvenience, taking care not to make the mass too thin.
It is difficult in many cases instantly to make a good fitting of large pieces of
iron work; this renders it necessary sometimes to join and separate the pieces
repeatedly before a proper adjustment is obtained. When this is required, the
white lead ought to predominate in the mixture, as it dries much slower than
the red. A workman knowing this fact, can be at little loss in exercising his
own discretion in regulating the quantities. It is safest to err on the side of
the white lead, as the durability of the cement is not thereby affected; a longer
time only is required for it to dry and harden. When the fittings will not
easily admit of so thick a substance as flannel being interposed, linen, paste-
board, or even paper, may be substituted. Stones that are broken, however
large, may be joined together very well with this cement, and cisterns put
together with it will never leak. In this case, the stones need not be entirely
bedded in it; an inch, or even less, of the edges that are to be next the water,
need only be so treated; the rest of the joint may be filled up with good lime.
Iron Cement. Take two ounces of muriate of ammonia, one of flour of
sulphur, and sixteen of cast-iron filings or borings. Mix them well in a mor-
tar, and keep the powder dry. When the cement is wanted for use, take one
part of this mixture, twenty parts of clear iron borings or filings, grind them
together in a mortar, mix them with water to a proper consistence, and apply
them between the joints. This cement is in extensive use by iron founders,
and is found to be very excellent, as in time it unites with the iron as one mass.
Cement for Iron Boilers. Six parts of clay, one of iron filings, and linseed
CEMENTS. 335
oil sufficient to form a thick paste, make a good cement for stopping cracks in
iron boilers.
Cement for Copper Boilers. Powdered quick lime mixed with bullock's blood
is often used by coppersmiths, to lay over the rivets and edges of the sheets of
copper in large boilers, as a security to the junctures, and also to prevent cocks
from leaking.
Cements for Jewellers, Lapidaries, &c. It sometimes happens, that jewellers,
in setting precious stones, by accident break off pieces; in this case they join
them, so that it cannot easily be seen, with gum mastic, the stone being pre-
viously made hot enough to melt it. By the same medium cameos of º
enamel, or coloured glass, are often joined to a real stone as a ground, to pro-
duce the appearance of an onyx. Mastic is likewise used to cement false backs
or doublets to stones, to alter their hue. The jewellers in Turkey, who are
generally Armenians, ornament watch-cases and other trimkets with gems, by
glueing them on. The stone is set in silver or gold, and the back of the setting
made flat to correspond with the part to which it is to be applied. It is then
fixed on with the following cement: isinglass, soaked in water till it swells up
and becomes soft, is dissolved in French brandy or in rum, so as to form a
strong glue. Two small bits of gum galbanum, or gum ammonicum, are dissolved
in two ounces of this by trituration, and five or six bits of mastic, as big as peas,
being dissolved in as much alcohol as will render them fluid, are to be mixed with
this by means of a gentle heat. This cement is to be kept in a phial closely
stopped; and when used, it is to be liquefied by immersing the phial in hot
water. This cement will resist moisture. Temporary cements are wanted in
cutting, grinding, or polishing optical glasses, stones, and various small articles
of jewellery, which it is necessary to fix on blocks, or handles, for the purpose.
Four ounces of resin, a quarter of an ounce of wax, and four ounces of whiting,
made previously red hot, form a good cement of this kind, as any of the above
articles may be fastened to it by heating them, and removed at pleasure in the
same manner, though they adhere very firmly to it when cold. Pitch, resin,
and a small quantity of tallow, thickened with brick dust, is much used at Bir-
mingham for these purposes. Four parts of resin, one of bees'-wax, and one
of brick-dust, likewise make a good cement. This answers extremely well for
fixing knives and forks in their hafts; but the manufacturers of cheap articles
of this kind too commonly use resin and brick-dust alone. On some occasions,
in which a very tough cement is requisite, that will not crack though exposed
to repeated blows, as in fastening to a block metallic articles that are to be cut
with a hammer and punch, workmen usually mix some tow with the cement,
the fibres of which hold its parts together. Seven or eight parts of resin, and
one of wax, melted together, and mixed with a small quantity of plaster of
Paris, is a very good cement to unite pieces of Derbyshire spar, or other stone.
The stone should be made hot enough to melt the cement, and the pieces should
be pressed together as closely as possible, so as to leave as little as may be of
the cement between them. This is a general rule in cementing, as the thinner
the stratum of cement interposed, the firmer it will hold.
Cement for Electrical Apparatus. One pound of bees'-wax added to five
pounds of resin, one pound of red ochre, and two table-spoonfuls of plaster of
Paris, all mixed together, make an excellent composition; but a cheaper one,
for cementing voltaic plates into wooden troughs, is made with six pounds of
resin, one pound of red ochre, half a pound of plaster of Paris, and a quarter
of a pint of linseed oil. The ochre and plaster of Paris should be well dried,
and added to the other ingredients in a melted state.
Universal Cement, particularly adapted for joining glass, porcelain, and
metallie surfaces, is thus prepared. To an ounce of mastic add as much highly
rectified spirits of wine as will dissolve it. Soak an ounce of isinglass in water
until quite soft, then dissolve it in pure rum or brandy, until it forms a strong
glue, to which add about a quarter of an ounce of gum ammoniac, well
rubbed and mixed. Put the two mixtures together in an earthen vessel, over a
gentle heat; when well united, the mixture may be put into a phial, and
kept well stopped. When wanted for use, the bottle must be set in warm
336 CEMENTS.
water, the china or glass articles must be also warmed, and the cement
applied. It will be proper that the broken surfaces, when carefully fitted, shall
be kept in close contact for twelve hours at least, until the cement is º set;
after which, the fracture will be found as secure as any part of the vessel, and
scarcely perceptible.
Cement for Chemical Glasses. Mix equal quantities of wheat flour, finely
powdered Venice glass, pulverized chalk, with half the quantity of fine brick-
dust, and a little scraped lint, into some whites of eggs. This mixture must
then be spread upon a linen cloth, and applied to the crack of the glasses; it
should be dried before they are put to the fire.
Cement for Stone Paper or Artificial Slates. Linseed oil rendered drying,
intimately mixed with white-lead and chalk; this should be used in a nearly
fluid state, as by doing so it will insinuate itself amongst the joints and interstices,
and cover the heads of the nails perfectly.
Water Cements, or Roman Cements, harden under water, and consolidate
almost immediately on being mixed, The ancient Romans, in making their
water cements, employed a peculiar earth obtained at the town of Puteoli.
This they called Pulvis Puteolanis: it is the same that is now called Puzzolana,
There is a substance called tarras, terras or trass, mostly employed by the Dutch
in their great aquatic structures. It is very durable in water, but inferior to the
other kinds in the air. In an analysis of Parker's Roman cement, by Monsieur
Berthier, he finds that its constituents differ so little from the constituents of
chalk and common clay, that he proposes the manufacturing of a similar cement
by the mere mixture of them in certain proportions. One part of clay, and
two and a half parts of chalk, sets almost instantly, and may therefore be
regarded as Roman cement. If clay and oxide of iron be mixed with oil,
according to Mr. Gad, of Stockholm, they will form a cement that will harden
under water. It has been discovered that manganese is a valuable ingredient
in water cements: four parts of grey clay are mixed with six of the black
oxide of manganese, and ninety of good limestone, reduced to fine powder;
then the whole is calcined to expel the carbonic acid. When this mixture }. been
well calcined and cooled, it is to be worked into the consistence of a soft paste,
with sixty parts of washed sand. If a lump of this cement be thrown into
water, it will harden directly.
Turners' Cement. Melt together resin one pound, pitch four ounces; and
while boiling-hot, add brick dust, until, by dropping a little upon a stone, you
perceive it hard enough; then pour it into water, and immediately make it up
in rolls, and it will be fit for use. A finer cement is made of pitch two ounces,
resin one ounce, and red ochre finely powdered. A small quantity of tallow is
used sometimes, according to the heat of the weather, more being necessary in
winter than summer. Either of these cements are of great use to turners. By
applying it to the side of a chuck, and making it warm before the fire, you
may fasten any thin piece of wood, which will adhere while it is turned;
when it is wanted off again, it need only be struck on the top with a tool, and
it will immediately fall off.
Rice Cement. This useful and elegant cement, which is beautifully white,
and dries almost transparent, is made by mixing rice flour intimately with cold
water, and then gently boiling it. Papers pasted together with this cement
will sooner separate in their own substance than at the joining. It is, there-
fore, an excellent cement in the preparation of curious paper articles, as tea-
trays, ladies' dressing and work boxes, and other articles which require layers
of paper to be cemented together. In every respect it is preferable to common
paste made with wheat flour. It answers well for pasting into books the copies of
writing taken off by copying machines on unsized silver paper. With this com-
position, made with a small quantity of water, that it may have a consistence
similar to plastic clay, models, busts, statues, basso-relievos, and the like, may
be formed. When dry the articles made of it are susceptible of a high polish;
they are also very durable. The Japanese make quadrille fish of this substance,
which so nearly resemble those made of mother-of-pearl, that the officers of
our East Indiamen are often imposed upon.
CENTRAL FORCES. 337
Parolic Cement. To prepare this cement, take the unsalted curd of skimmed
milk, after pressing the whey out of it, and break it into lumps; distribute these
lumps upon linen sheets laid upon the floor of an airy room to dry; and fre-
quently, from time to time, as the curd acquires greater consistency, stir and
break it into smaller masses, either with the hands, or with the assistance of
a flat board, and a bar or rubber of wood, until at length it becomes dry
enough to grind in a steel coffee-mill to a powder about as fine as the best
gunpowder, when it must be gently dried over a stove, and kept dry for use.
100 lbs. of curd from the cheese-press will only afford about 30 lbs. of the dry
curd. To 90 parts of this dried curd, 10 parts of caustic quick lime, made of
lue marble, finely rubbed to powder and searced, and 1 part of camphor, must
be added, and well mixed, by rubbing the whole together with a pallet-knife
upon a stone slab; and the whole must be then inclosed in bottles, holding
about an ounce each, and well corked immediately afterwards, in order to pre-
vent the access of air to the composition. In this state the cement will remain
good a long time; and when wanted for use, a little of it must be poured out
upon any flat earthen plate, &c., and, by the aid of a pallet or case-knife, be
instantly mixed with a proper quantity of water, to render it of a fit consistency
for the purpose to which it is to be applied. The bottle must be again carefully
closed, after taking out the quantity of cement required, as, otherwise, the lime
would lose its causticity, upon which its solvent action, or the caseous part of
the cement, entirely depends.
The manufacture of that important and valuable cement, glue, is described
in its initial order in this work.
CENTRAL FORCES. The two antagonist forces by which bodies are
caused to revolve round a central point. As all forces act in right lines, the
tendency of any body moving in a circle is to fly off in a right line forming
a tangent to the circle, and this tendency is called the centrifugal force; and
the force by which it is restrained from so flying off, and which maintains it in
its curvilinear path, is termed the centripetal force; and these two forces are
necessarily equal to each other. Dr. Brewster has summed up the whole
doctrine of the central forces in the following propositions. 1. The centrifugal
forces of two unequal bodies moving with the same velocity, and at the same
distance from the centre of motion, are to one another as the respective quantities
of matter in the two bodies. 2. The centrifugal forces of two equal bodies
which perform their revolutions round the central body in the same time, but at
different distances from it, are to one another as their respective distances from
the central body. 3. The centrifugal forces of two bodies which perform their
revolutions in the same time, and whose quantities of matter are inversely as
their distances from the centre, are equal to each other. 4. The centrifugal
force of two equal bodies moving at the same distance from the central body,
but with different velocities, are to one another as the squares of the velocities.
5. The centrifugal forces of two unequal bodies moving at equal distances from
the centre with different velocities, are to one another in the compound ratio of
their quantities of matter and the squares of their velocities. 6. The centrifugal
forces of two equal bodies moving with equal velocities at different distances
from the centre, are inversely as their distances from the centre. 7. The
centrifugal forces of two unequal bodies moving with equal velocities at different
distances from the centre, are to one another as their quantities of matter
multiplied oy their respective distances from the centre. 8. The centrifugal
forces of two unequal bodies moving with unequal velocities at different dis-
tances from the centre, are in the compound ratio of their quantities of matter,
the squares of their velocities, and their distances from the centre.
To find the centrifugal force of any body:-Divide the velocity in feet per
second by 4.01, and the square of the quotient by the diameter of the circle;
the quotient is the centrifugal force when the weight of the body is 1. Hence
the quotient, multiplied by the weight of the body, is the centrifugal force
required.—Ex. Required the centrifugal force of the rim of a fly-wheel 20 feet
in diameter, moving with a velocity of 32; feet per second :
32}+4.01–8.02 and 8.02%--20-3.216 times the weight of the rim.
338 CENTRE OF PERCUSSION.
Rule 2.—Multiply the square of the number of revolutions per minute, by the
diameter of the circle in feet, and divide the product by the constant number 5870,
and the quotient is the centrifugal force when the weight of the body is l;
and this quotient, multiplied by the weight of the body, is its centrifugal force.
Ex. Required the centrifugal force of a stone weighing 2 lbs., revolving in a
circle of 4 feet diameter, at the rate of 120 revolutions per minute :
576.00
| 202 *= 1– =9.81
120° X 4-57600 and 5870
hence 9.81 × 2–19.62 centrifugal force.
CENTRE OF GRAVITY. A point in any body about which all the
parts are in equilibrio; so that if the body be suspended or supported by this
point, it will remain in any position in which it may be placed. The centre of
gravity of any plane may be found mechanically as follows: suspend the plane
by a point in or near its perimeter, and when it is at rest, draw across it a
vertical line, passing through the point; suspend it in like manner by another
point, and draw a vertical line as before; the intersection of these lines is
the centre of gravity.
CENTRE OF GYRATION is that point in a body revolving about an axis,
into which, if the whole quantity of matter were collected, the same moving force
would generate the same angular velocity.—To find the centre of gyration: mul-
tiply the weight of the several parts of the body by the squares of their distances
from the centre of motion, and divide the sum of the products by the weight
of the whole mass, and the square root of the quotient will be the distance of
the centre of gyration from the centre of motion.
CENTRE OF OSCILLATION is that point in a body suspended from a
point and made to vibrate, in which all its force is collected, and to which point,
if an obstacle were applied, all its motion would cease. To find the centre of
oscillation in a compound pendulum:-Multiply all the parts or bodies of which
the pendulum is composed, each by the square of its distance from the point of
suspension, and divide the sum of the products by the product of the whole
weight of the pendulum, multiplied by the distance of the centre of gravity
from the point of suspension.
CENTRE OF PERCUSSION. That point in a body revolving about a fixed
axis into which the whole force or motion is collected; it is, therefore, that point
of a revolving body which would strike an obstacle with the greatest effect, and
from this property it has received the name of the centre of percussion. The
centres of percussion and of oscillation are generally treated separately, but
the two centres are in the same point, and therefore their properties are the
same. As in bodies at rest the whole weight may be considered as collected in
the centre of gravity, so in bodies in motion, the whole force may be considered
as concentrated in the centre of percussion; therefore, the weight of the rod
multiplied by the distance of the centre of gravity from the point of suspension,
will be equal to the force of the rod divided by the distance of the centre of
percussion from the same point. For example ; suppose a rod, 12 feet long,
and weighing 2 lbs. per foot, with two balls of 3 lbs. each, one fixed 6 feet
from the point of suspension, and the other at the end of the rod; what is
the distance between the points of suspension and of percussion ?
12 × 2 × 6=144 momentum of rod.
3 X 6 = 18 ditto of first ball.
3 × 12 = 36 ditto of second ball.
198 momentum of balls and rod;
and the weight of the rod multiplied by the square of its length, and divided
by 3–to the force of the rod; and the weight of the ball multiplied by the
square of their distance from the point of suspension=to tº , force of the ball.
Therefore—
CERUSE. 339
24 x 144 . . . .
3
3 X 36= 108 ditto of the first ball
3 × 144= 432 ditto of the second ball
1692=force of balls and rod,
and 1692-198=8.545 feet from the point of suspension. In a slender rod, of
small breadth as compared with its length, the distance of the centre of percussion
is nearly two-thirds of its length from the point of suspension. In an isoceles
triangle, suspended by its apex, and vibrating in a plane perpendicular to itself,
the distance of the centre of percussion is three-fourths of its altitude; and the
same thing holds with regard to fly-wheels, or wheels in general.
CENTRE, or CENTERING. The framing of timber by which an arch or
vault is supported during its erection. See BRIDGE.
CENTRIFUGAL MACHINE. A machine invented by Mr. Erskine for
raising water by means of a centrifugal force combined with the pressure of the
atmosphere. This machine consists of a vertical tube resting upon a pivot, and
having at top two horizontal hollow arms, near the extremity of each of which,
but on opposite sides, is a valve opening outwards; whilst near the bottom of
the vertical tube, and below the surface of the water to be raised, is a valve
opening inwards. On the upper part of the arms are two holes, with screw-
caps, and through these holes water is poured previous to setting the machine
in motion; by which means the air is forced out of the machine, and the water
supported in the tube by the foot-valve at the bottom. The holes in the arms
being secured by their screw-caps, and a rapid rotatory motion being commu-
nicated to the tube, the water in the arms acquires a centrifugal force, opens
the valves near the extremity of the arms, and flies out with a velocity nearly
equal to that of the arms, discharging itself into a circular trough. Although
extremely ingenious and simple, this machine is not equal in effect to a well-
made pump; and as the fluid is forced up the vertical tube into the arms by
the pressure of the atmosphere, it is incapable of raising water to a height
exceeding 33 feet.
CERATE. A compound of hog's lard or oil with bees' wax, employed in
SUlrgerW. -
#n. That part of common wax which is dissolved by alcohol.
CERIUM. A newly discovered metal found in the mineral cerite. It has
not yet been obtained in a useful metallic form.
CERUSE, or WHITE LEAD, is commonly made by coiling up very thin cast
sheets of lead into rolls, so as to leave a small space between each fold. The
rolls thus formed are lightly jammed into the mouths of a number of earthen-
ware pots, which are about half filled with vinegar. These pots are placed in
a situation where a very gentle heat will cause a slow evaporation of the
vinegar, in order that it may gradually operate upon the lead. A layer of
several hundreds of them are usually deposited either in a bed of tanner's spent
bark, or dung, contained in a wooden frame. Boards are then laid over the
tops of these pots, and on this temporary floor, which is supported by boards
F. edgeways, is laid another layer of pots similarly furnished. Seven such
ayers of pots are placed in succession over each other, to form a stack. When
the vinegar is found to be completely evaporated in these stacks, which
generally occupies three months, they are taken down; the corroded lead is
taken out of the mouths of the pots, but as the adhesion to the latter is very
strong, many of them are broken in getting out the lead, and the poisonous
dust which the workmen inspire by this operation, lamentably impairs their
health, and they are often in consequence afflicted with the disease called the
Devonshire, or painter's colic. To avoid this serious evil, and economize the
process, a different and more mechanical arrangement has been made. The base
of the stack is made of a layer of pots filled with vinegar only; over these is
supported, by planks on edge, a floor of boards, pierced with numerous holes
to allow the passage of the acid vapour; on these perforated boards are then
340 CHAIN.
laid the rolls of lead, then another perforated floor, and another layer of rolls,
until the stack is completed. By this arrangement it is said that the manufac-
turer obtains one-third more white lead, saves his pots from breakage, and
avoids the dust so pernicious to the workmen by first sprinkling the rolls with
water. Upon uncoiling the plates, the white substance that falls off is the purest
white lead, and is disposed of for the finest work under the name of flake white;
a portion of the latter is ground up with water, formed into small lumps, and
sold under the name of ceruse. But all the white lead that is subsequently
taken off the plates is ground up either with water, and sold in large lumps, or
it is ground with oil, and is usually more or less adulterated with whiting, to
suit the various prices at which it is required in the market. As the processes
employed in France and Germany for the manufacture of ceruse appear to be
well worthy of attention, we shall here annex some account of them. In
France the first part of the process consists in dissolving 174 lbs. of finely-
ground litharge in 65 lbs. of pyroligneous acid, of such strength that 22% grains
of this acid will saturate 25 grains of sub-carbonate of soda; fifteen to twenty
times as much water is usually added. The whole is left for a short time, and
the clear portion being decanted off, some fresh acid and water is poured on the
sediment, to take up any oxide that might have escaped the action of the first
parcel. The decanted solution is run into large shallow covered cisterns, into
which carbonic acid gas is passed through numerous pipes. When the settling
appears to be completed, the whole is passed into a deep cistern, and left there
for some hours, when the liquid part is to be poured off, in order to be combined
with more litharge, some fresh acid being also added. After the desired tint
has been given to the lead, it is well drained, put into glazed pots of the proper
shape to imitate the Dutch white lead leaves, then dried in stoves, and lastly,
packed in blue paper to heighten the effect of its beautiful colour.
In Germany the first part of the process consists in casting the pure lead of
Corinthia into very thin sheets, which is effected by pouring the liquid metal
upon inclined sheets of iron. The sheets of lead are trimmed to a proper size,
and suspended over an acid liquor contained in boxes, which are usually about 5
feet long, 1 foot broad, and 10 inches deep; and they are pitched internally on
the bottom, and rising therefrom about 2 inches at the sides. Sticks are placed
across the boxes, and the sheets of lead are doubled so as to be suspended in the
middle by them, but so as not to touch each other, nor the acid liquor deposited
underneath them. The liquor in some manufactories is made of equal parts of
vinegar (obtained from crab apples) and wine lees, and about two gallons of this
mixture is apportioned to each box. Some manufacturers use 20 pints of vinegar,
8 pints of wine lees, and 1 lb. of pearl ash. The usual mode is to dispose the
boxes in a large room heated up to 879 Fahrenheit; a greater heat would
evaporate the acid too fast. In about a fortnight the corrosion is finished,
rendering the sheets about a quarter of an inch thick, and partially covered
with crystals of sugar of lead. Those crystals that are easily detached are
carefully washed; during this operation a white scum appears, which is taken
off, and a little pearl ash being added to it, it is changed into ceruse of a beautiful
whiteness, and is sold for the choicest purposes; the remainder is mixed in
different proportions with the pure sulphate of barytes, brought from the Tyrol.
CETINE. The name given by Chevreul to spermaceti, which is extensively
adopted. See FAT.
CHAFF-CUTTING MACHINE, as its name denotes, is a machine for
cutting chaff for cattle, which being an object of some consequence on large
farms, and in establishments employing many horses, a variety of machines
have been invented for the purpose of performing the operation with facility
and dispatch. For a highly-improved machine of this description, see the
article STRAw.
CHAIN. A series of links of metal engaged one within the other; also,
in surveying, a measure of length, made of a certain number of links of iron
wire. That which is most commonly used for this purpose, called Gunter's
chain, is composed of 100 links=4 poles, or 66 feet; and 1 square chain=
10,000 links=16 poles; 10 square chains=100,000 links=160 poles=1 acre
CHEESE. 34]
CH A IN PUMP. See PUMPs.
CHALDRON. . An English measure for coals, containing 12 sacks, or 36
bushels. The bushel measures are always heaped up, and on shipboard, 21
chaldrons are allowed to the score.
CHALK. A species of carbonate of lime.
CHALYBEATE., Mineral water impregnated with iron is so called.
CHARCOAL., The fixed residue of vegetables exposed to a strong heat
whilst protected from the access of the atmospheric air. In countries where
wood abounds, charcoal is prepared by forming it into a conical stack, covered
with clay and turf to the depth of several inches, leaving an aperture at the
top for the escape of the smoke, and several small apertures at bottom for the
admission of air at first lighting of the pile, but which are carefully closed as
soon as the ignition is supposed complete. Charcoal is also made on a great
scale by charring wood in iron cylinders, as described under the head of Acetic
AgD. Charcoal has been prepared lately in France from turf or peat, and is
said to be superior to that prepared from wood. In a goldsmith's furnace it
fused 11 ounces of gold in 8 minutes; whilst wood charcoal required 16 minutes
to produce the same effect. The malleability of the gold, too, was preserved
in the former instance, but not in the latter. From the scarcity of wood in this
country, pitcoal charred is much used instead of charcoal, and is known by the
name of coke.
CHARGE, in gunnery, the quantity of powder and shot which is necessary
to load a piece of ordnance, in order that when fired it may produce the in-
tended effect. For proving guns the weight of the powder is always equal to
that of the ball; but the charge of powder generally esteemed sufficient for
service is one-half or one-third the weight of the ball, or even less. Dr.
Hutton found, from many experiments, that the length of the charge producing
the greatest velocity, in guns of various lengths of bore, from 15 to 40 cali-
bres, is as follows:–
Length of bore. Length of charge.
3 N
15 io
20 3.
calibres. º the length of the bore.
30 I6
3
40 20
CHAYA ROOT. The root of Oldenlandia umbellata, which grows wild on
the coast of Coromandel, and is likewise there cultivated for the use of the
dyers and calico printers. It is used for the same purposes as madder with us,
to which it is said to be far superior, giving the red so much admired in the
Madras cottons.
CHEESE. An article of food obtained by mixing an acid with milk, which
causes it to coagulate and form a curd; the curd is then subjected to the action of
a powerful press to separate it from the whey, after which it is set upon racks
to dry. The quantity of curd is less when a mineral acid, than when a vege-
table acid is used; but the substance which answers best for this purpose, and
indeed which is almost the only one employed in England, is rennet, which is
made by macerating in water the last stomach of a calf, salted and dried for
this purpose. Cheese is made in several parts of England, but that made in
Chester is generally esteemed superior to all others. An excellent account of
the mode of making it will be found in Vol. XI. of Tillock's Magazine, taken
from the agricultural report of the county. “If the milk,” says the reporter,
“be set together very warm, the curd, as before observed, will be firm; in this
case, the usual mode is to take a common case knife, and make incisions across
it to the full depth of the blade of the knife, at the distance of about 1 inch,
and again crossways in the same manner, the incisions intersecting at right
angles. The whey rising through these incisions is of a fine pale green colour.
The cheese-maker and two assistants proceed then to break the curd; this is
performed by their repeatedly putting their hands down into the tub, the cheese-
X X
342 CHEMISTRY.
maker with the skimming dish in one hand, breaking every part of it as they
catch it, raising the curd from the bottom, and still breaking it. This
part of the business is continued till the whole is broken uniformly
small; it generally takes up about 40 minutes, and the curd is then left
covered over with a cloth to subside.” The cheese is subsequently broken
by hand, mixed with salt, and put into a vat, in which it is pressed with
loaded boards, and then is turned over upon a cloth into another vat, with a
tin hoop or binder over the upper part of the cheese, and within the sides of
the vat, and then pressed for about 8 hours, being twice turned in the vat
during that time. . It is then set to dry, being turned twice a day for the first
week, and then cleared and turned once daily for three weeks longer, after
which it is removed to the common cheese-room, where it is laid upon straw
upon a boarded floor until it acquires the proper hardness.
CHEMISTRY is the science which teaches the composition, properties, and
uses, of all material bodies. It is the business of Mineralogy to investigate the
properties and uses of inorganic substances as they naturally occur, but it is
the office of chemistry to reduce, not only them, but all organic bodies, to their
primitive elements, and having discovered the component parts and their pro-
portions, to aim at their reproduction, when such reproduction would be beneficial
to man. Under this head we shall give but a short sketch of this extensive
science, as it will be necessary to explain the nature and mode of operation of
those potent agents, Light, Heat, and Electricity; and as each substance which
is the object of chemical research will be described under the initial letter of its
name. For the history of this science we must refer our readers to Brande's
Manual, or some other systematic work on the science, as its details would be
far too multifarious to be compatible with the limits of this work. The science
of chemistry will be found to depend chiefly on the operation of the different
degrees of attraction which the various elementary bodies have for each other.
Every mass of matter on the earth, or diffused through the universe, is found to
tend towards every other mass. This tendency is expressed by the term gravi-
tation, and it is found to increase in intensity as the masses are nearer in the
proportion of the squares of the distances between them. If, however, we
examine this power in individual masses, we shall find it act with much greater
intensity, and to vary its force in different bodies; it is then called affinity.
The former species of attraction, or that acting on masses at sensible distances,
forms the particular object of study in mechanical philosophy; while the action
of the particles on each other at insensible distances is the object of chemical
philosophy. When this affinity acts between particles of the same kind, it is
called cohesion; but when it operates between particles of a different kind, it is
called chemical attraction, the attraction of composition, or sometimes simply
affinity. One particle of copper is attached to another particle of copper by
cohesion; also a particle of sulphate of copper to another particle of the same
substance; but when a particle of copper unites with a particle of sulphuric or
nitric acid, it is an instance of chemical affinity. The attraction of cohesion,
as well as the power of repulsion, which is opposed to it, are both opposed to
chemical attraction. A lump of sugar or salt is much more readily dissolved
if previously broken into pieces or pulverized, than if left in the solid form
which cohesion imparts to it. Chemical attraction has been distinguished into
three degrees or states of energy: the result of the lowest kind is mixture; of
the second, solution; and of the third and most energetic, composition. Chemical
mixture takes place when the particles of two bodies are in a like state, and
the power of cohesion, with regard to them, so far suspended, as to admit of
that freedom of motion between themselves upon which fluidity depends; thus,
two liquids or two ačriform fluids may admit of mixture, but two solids can be
chemically mixed only by diminishing their cohesion by means of heat to such
a degree as to bring one or both to the state of liquids. Between some fluids
there appears to be no attraction, and hence they do not admit of mixture ;
thus, if water and oil, or water and mercury be agitated together, they will
separate as soon as they are allowed to remain at rest, the denser body occupying
the lower place; but sulphuric acid and water, or alcohol and water, have a
CHEMISTRY. 343
strong attraction for each other, and when mixed, do not separate by repose,
although the density of the ingredients materially differs. The atmosphere in
which we live and breathe is an example of the mixture of ačriform bodies:
it is composed of two gases–oxygen and nitrogen, which are mingled with
surprising uniformity. They may be separated from each other, and the pro-
perties of the latter exhibited, by burning a little sulphur under a bell glass
over water. By this process the oxygen is removed, combining with the sulphur,
and the nitrogen remains. The properties of these gases will be discussed
hereafter under their respective names. Unlike liquids, all ačriform bodies have
the property of mixing together. This difference is considered to arise from a
modification of attraction between their constituent particles. In the case of
liquids not mixing, the attraction of cohesion between similar particles is pro-
bably greater than the chemical attraction between the dissimilar particles. In
gaseous bodies the attraction of cohesion does not appear to exist, and chemical
mixture operates unopposed. The expansive power of heat is opposed to
cohesion, and hence this attraction may be so far counteracted, that solid bodies
shall assume the fluid state, and may then be mixed together; thus, melted tin
may be mixed with melted lead, or copper, and their particles remain combined
after they have resumed the solid state. Chemical mixture may take place
between two bodies in any proportion. Equal measures of sulphuric acid and
water may be commingled, or a single drop of the former may be mixed with
a pint or a gallon of the latter, and the mixture will be uniform and perfect.
Chemical mixture is often attended by condensation or diminution of volume.
If equal measures of sulphuric acid and water are mixed, the mixture will not
fill two measures: this contraction is usually accompanied with an increase of
temperature. If four parts of sulphuric acid be suddenly mixed with one of
water, both at ordinary temperatures, the heat of the mixture will be higher
than that of boiling water. The properties of bodies are not essentially changed
by moisture; in general, however, those of the more active prevail. A few
drops of sulphuric acid will communicate a sour taste to a quart of water.
The separation of liquid mixtures may be effected either by the addition or
subtraction of heat, arising from the unequal effect produced by this agent on
different bodies. By carefully applying heat to a mixture of alcohol and water,
the spirit will rise in vapour, and leave the water pure; this process is called
evaporation. If the more evaporable fluid is condensed and received into a
separate vessel, it is termed distillation. This process may easily be performed
in a small way by using a retort
and receiver. In the annexed cut
a is the retort, containing the mixed
liquid, which may be spirit and
water, or a little wine or ale; b is
the receiver, into which the neck
of the retort must pass through a
cork; c is the spirit lamp, which
furnishes heat for the distillation.
As soon as the heat is applied, the
spirit being more easily vapourized,
rises to the top of the retort, where,
being condensed into the liquid
state, it slowly trickles down the
neck into the receiver. The neck of the retort and the receiver may be kept
cool, by applying cloths, constantly moistened with cold water, to their external
surface. The spirit may also be separated from the water by intense cold,
which freezes the water, and leaves the spirit in its liquid state. Mixtures of
gaseous fluids are not separable by heat or cold, for they all expand equally by
equal additions of heat; but steam, and other vapours, may be separated from
gases by reduction of temperature, which destroys the elasticity of the former,
but not of the latter. The second degree of chemical attraction is solution,
which operates between solids and liquids, or gases and liquids; the liquids, in
these cases, are called solvents. Between some liquids and solids attraction

344 CHEMISTRY.
does not exist, or it is overbalanced by the cohesive power. Resin and sealing
wax are insoluble in water, but readily dissolve in alcohol. Chemical attraction
may be exerted in different degrees between one body and several others,
There is an affinity between alcohol and water, whereby they are capable of
mixing; there is also a mutual affinity between alcohol and resin, by which the
former dissolves the latter; but there is no affinity between water and resin.
Now, if water be added to a solution of resin in alcohol, the resin will resume
the solid form; the attraction between the particles of alcohol and those of
water is greater than that between the particles of resin and alcohol: the
consequence is, that the alcohol quits the resin and combines with the water.
and the resin falls to the bottom of the liquid. This is called elective attraction,
because the alcohol may be considered as exercising a choice between the
substances with which it is capable of combining. This resumption of the
solid form by a body previously dissolved in a liquid, is termed precipitation.
The power of solution is limited, as liquids cannot combine with more than a
certain definite quantity of any solid or aeriform body. The point at which
the action between the two bodies ceases is called the point of saturation. Up
to this point the two bodies may combine in any proportions. A solvent that
has been saturated with one substance, is often capable of combining at the
same time with others; thus water that is saturated with saltpetre will dissolve
a considerable quantity of common salt. The influence of heat upon the power
of solution corresponds with the difference between cohesion and elasticity.
Upon solid bodies it generally increases the power of the solvent by diminishing
their cohesion. Upon aériform bodies it diminishes the power by increasing
their elasticity. Solvents may be separated from the bodies with which they
are united by alterations of temperature. If a solution of alum or common
salt be boiled, the liquid will be dissipated in vapour, but the solid salt will
remain. If a solution of carbonic acid in water be frozen, the gas will escape
and the water remain in the solid state. The result of the highest degree of
chemical attraction is composition, which may take place between bodies under
every modification of cohesive attraction. Bodies that unite in this intimate
manner combine only in definite proportions, which are invariable in the same
compound. Combination usually produces a total change in the sensible pro-
perties of the combining substances; and the process is generally accompanied
by change of temperature, to such an extent sometimes that light and heat
are emitted in abundance. If copper filings and sulphur be mixed together,
and heat applied as soon as the sulphur melts, a violent action will take place,
the copper will become red hot, and a black brittle body will be formed, with
properties totally different from those of its two ingredients. This compound,
which is the sulphuret of copper, is often found ready formed in mineral veins;
but whether existing naturally, or formed by art, its composition is definite and
invariable. It is found to consist of 64 parts by weight of copper, and 16 of
sulphur. There is, however, another compound of copper and sulphur, in
which the proportions are 64 copper to 32 of sulphur. In this it will be seen
that the quantity of sulphur is exactly double of that which the first combi-
nation contains. This is a fact of common occurrence; many bodies will unite
in two or three different proportions, but they are no less definite, each being a
multiple, or a submultiple, of the preceding; that is, it is double, triple, or
half, and so on. This is well illustrated in the compounds of mercury. If
this brilliant and fluid metal be agitated for a long time in contact with the
common air, it will unite with the oxygen of that mixture, and will be con-
verted into a black, insipid, insoluble powder, which consists of 200 parts of
mercury to 8 of oxygen. If instead of being agitated at common temperatures
with the air it be kept nearly boiling in it, it will be converted into a red
shining mass, endued with an acrid metallic taste, and which is soluble in
water, and poisonous. This consists of 200 parts of mercury, and 16 of
oxygen. , Again, if mercury be rubbed in a mortar with sulphur, it unites
with a given proportion. If the mercury be poured into melted sulphur,
and strongly heated, a compound will be formed which rises in vapour, and
concretes on cooling into a brilliant red substance, known as cinnabar or
CHEMISTRY. 345
vermilion. In this the quantity of sulphur is double of that in the preceding
compound. Another compound of mercury is the well-known medicine called
calome), which is formed by the union of the metal with a gas named chlorine.
The compound is heavy, white, tasteless, crystalline, and nearly insoluble in
water. It may be taken in doses of several grains without any effect but that
of a purgative. It is composed of 200 parts of mercury, and 36 of chlorine.
If, however, the mercury be made to combine with 72 parts of chlorine, it
produces corrosive sublimate, a semitransparent white mass, of an acrid, nau-
seous, metallic taste, soluble in water and alcohol, and highly poisonous. In
these examples, it will be seen that substances comparatively inert, may
produce by their union compounds of highly active properties; and that a
compound of two bodies, which, in one proportion, if taken internally, will have
but a slight effect upon the animal frame, if united in a different proportion
will prove destructive to life. On the other hand, highly active bodies of
opposite properties will also produce, by their union, substances of a mild cha-
racter, and they are then said to neutralise each other. Sulphuric acid, or oil
of vitriol, is highly corrosive, and intensely sour. If brought into contact with
any substance stained with vegetable blue colours, as those of violets or litmus,
it instantly changes them to a bright red, a property which belongs to all the
acids. Barilla, or carbonate of soda, is a solid that is soluble in water, of a
hot, acrid, bitter taste. It changes the blue colour of vegetables to green,
which property is common to all alkalies. If into a solution of this substance
we carefully drop a portion of the former, a brisk effervescence will ensue, and
carbonic acid will be given off. If the experiment be performed with care, and
the affusion of the acid stopped the moment the effervescence ceases, the solu-
tion will be found to be warm, and possessed of properties totally different
from those of the acid or alkali from which they have been formed; it will no
longer be sour, corrosive, acrid, or hot; it will have no action on vegetable
colours, and all the active properties of the original bodies are said to be neu-
tralised. The compound is slightly bitter, saline, and cooling. If part of the
water be evaporated by heat, a solid will be deposited in regular crystalline
forms, called sulphate of soda, or Glauber's salt. The operation of affinity,
which produces chemical composition, exists in a body in different degrees
towards other bodies; and if to a compound of two bodies a third be pre-
sented which has a stronger attraction for either of the component parts than
they have for each other, a decomposition will take place, and a new compound
will result. Carbonate of soda is composed of carbonic acid and soda ; and in
the experiment above referred to, it is decomposed, the sulphuric acid uniting
with the soda, and the carbonic acid escaping in the gaseous state. In like
manner, if a solution of carbonate of soda be boiled with caustic lime, the car-
bonate of soda will be decomposed, the carbonic acid will quit the soda and
unite with the lime, forming carbonate of lime or chalk, and caustic soda will
remain in the solution. These affinities are conveniently represented in the
following diagrams:—
Carbonic acid.
C sº
arbonate of soda | Soda. Sulphuric acid.
S-N-
Sulphate of soda.
Soda.
Carbonate of soda
Carbonic acid. Lime.
Carbonate of lime.
In these diagrams the substance at bottom is the new compound, which is pre-
cipitated, or thrown down, and that at the top either escapes or remains in
solution; this action is called single elective affinity. If two compounds are
346 CHEMISTRY.
brought together in solution, it not unfrequently happens that a process of
double decomposition and composition occurs; that is, the two original bodies
are decomposed, and two new compounds produced, by a mutual interchange
of ingredients : this compound action has been named double elective affinity.
Decomposition, which cannot be effected by single, may by double elective
affinity. Sugar of lead, or acetate of lead, is a compound of acetic acid and
lead. White vitriol, or sulphate of zinc, is compounded of sulphuric acid and
zinc. If in a solution of acetate of lead we suspend a piece of metallic zinc,
we shall have an example of single elective affinity; the acetic acid will act
upon the zinc, and the lead will resume its metallic state, and be precipitated
on the zinc in a beautiful arborescent form. But if a solution of acetate of
lead be mixed with a solution of sulphate of zinc, the acetic acid will unite
with the zinc, and, at the same instant, the sulphuric acid will combine with
the lead, forming an insoluble precipitate, which will fall to the bottom of the
vessel while the acetate of zinc remains in solution. The latter is an instance
of double elective affinity, and may be represented by the following diagram:—
Acetate of zinc.
Acetic acid. Zinc.
Acetate of *| } Sulphate of zinc.
Lead Sulphuric acid.
\–mºsºm-ºw-mºsºm-Z
Sulphate of lead.
Here the original substances are placed on the right and left of the diagram,
while the new compounds occupy the top and bottom.
Having given a general view of the nature of chemical attraction, we shall next
proceed to sketch the most important facts as connected with this subject relative
to light, heat, and electricity. The phenomena resulting from the motion of light
will be found in the article OPTIcs; we shall, therefore, in the present sketch,
refer to the mechanical properties of light only so far as is necessary to render its
chemical effects intelligible. When a pencil of light is admitted through a hole in
a window shutter into a darkened room, and made to fall on a triangular glass
prism, it is turned out of its natural or straight-lined direction, and prevented
from falling on the floor, where it would produce a spot of white light, instead
of which it forms a spectrum of splendid colours on the wall, or on a screen
placed to receive it. From this circumstance it appears that light is compound
and separable by means of an inequality in the refrangibility. In the annexed
diagram a b represents a ray of light,
which falling on the prism e, is diverted
from its course, and dispersed into
colours occupying the space c d. The
colours, proceeding from the bottom,
are red, orange, yellow, green, blue,
indigo, and violet, according to Sir }
Isaac Newton's observation; but some
modern observers state that there are
only red, green, blue, and violet, in
the spectrum, when it is formed as it .22
should be, with a very small pencil of **
light. The violet occupying the upper part of the spectrum, is most diverted
from its course, and is said, therefore, to be the most refrangible. The red is
the least refrangible. This effect is very similar to that of elective attraction,
for the same glass acts with different force on different rays; and this analogy
is extended by the observation that different kinds of glass, as well as other
substances, disperse light in different proportions. If these differently coloured
rays of light thus separated by the prism be concentrated on one spot by means
of a lens, they will reproduce colourless light. If the spectrum produced, as
we have stated, be minutely examined, it will be found to have different pro-
Perties in different parts. Thus the red end will most sensibly affect the
(;
-Fe-
*



CHEMISTRY. 347
thermometer; the lightest green rays are most illuminative, and the violet and
produces the most decided chemical changes. If the white luna cornea, the
muriate of silver, be moistened and exposed to the different rays in the pris-
matic spectrum, it will be found that no effect is produced upon it in the least
refrangible rays, which occasion heat without light. A slight discolouration
will be occasioned by the red rays, but the blackening power will be greater in
the violet than in any other ray; and beyond the violet, in a space perfectly
dark, the effect was still perceptible. This observation shows that there are
rays more refrangible than those which produce heat and light. Sir H. Davy
found that a mixture of chlorine and hydrogen acted more rapidly upon each
other, combining without explosion, when exposed to the red, than when placed
in the violet rays; but that solution of chlorine in water became solution of
muriatic acid most rapidly when placed in the most refrangible rays of the
spectrum. He also observed that the puce-coloured oxide of lead, when mois-
tened, gradually gained a tint of red in the least refrangible rays, and
at last became black, but was not affected in the most refrangible. The
same change was produced by exposing it to a current of hydrogen gas.
Dr. Wollaston found that guaiac, exposed to the violet rays, passed rapidly
from yellow to green. MM. Gay Lussac and Thenard applied the same
influence to a gaseous mixture of hydrogen and chlorine, when an explosion
immediately took place. By placing small bits of card, coated with moist horn
silver, or little phials of those mixed gases, in different parts of the spectrum,
M. Berard verified the former observations, of the chemical power acquiring its
maximum in the violet ray, and existing even beyond it; but he also found by
leaving the tests a sufficient time in the indigo and blue rays, a perceptible
effect was produced by them also. He concentrated by a lens all that portion
of the spectrum which extends from the green to the extreme boundary of the
violet, and by another lens he collected the other half of the spectrum, com—
prehending the red. The latter formed a focus of white light so brilliant that
the eye could not endure it, yet in two hours it produced no sensible effect on
muriate of silver. On the contrary, the focus of the other half of the spectrum,
whose light and heat were far less intense, blackened the muriate in ten minutes.
The sun beams, in traversing a coloured glass, produce similar effects. Thus,
the chloride of silver acquires a black tint behind a blue or violet glass, but
does not blacken behind a red or orange glass. On the other hand, it becomes
red behind a red glass, and that much more quickly than even in the solar
spectrum. With respect to the light emitted by gases, even the bright light of
olefiant gas, when concentrated so as to produce a sensible degree of heat,
occasioned no change on the colour of muriate of silver, nor on a mixture of
chlorine and hydrogen ; while the light emitted by electrized charcoal speedily
affects the muriate, and causes these gases to unite rapidly, and sometimes with
explosion. Sir H. Davy has remarked, that the refraction and effects of the
solar beam offer an analogy to the agencies of electricity. In the voltaic
circuit, the maximum of heat seems to be at the positive pole, where the
power of combining with oxygen is given to bodies, and the agency of rendering
bodies inflammable is exerted at the opposite surface; and similar chemical
effects are produced by negative electricity, and by the most refrangible rays of
the solar beam. In general, in nature, the effects of the solar rays are very
compounded. Healthy vegetation depends upon the presence of the solar
beams, or of light; and whilst the heat gives fluidity and mobility to the
vegetable juices, chemical effects likewise are occasioned—oxygen is separated
from them, and inflammable compounds formed. Plants deprived of light
become white, and contain an excess of saccharine and aqueous particles, and
flowers owe the variety of their hues to the influence of the solar beams. Even
animals require the presence of the rays of the sun, and their colours seem
materially to depend upon the chemical influence of these rays; a comparison
between the polar and tropical animals, and between the parts of their bodies
exposed, and those not exposed to light, shows the correctness of this opinion.
Light is produced in several natural operations, most of which may be con-
sidered in this place. If two pieces of quartz be rubbed together, light is
348 CHEMISTRY.
produced even under water. Atmospheric air, or oxygen, quickly and violently
compressed in a glass syringe, or a glass ball filled with the latter, and suddenly
broken in vacuo, produces light. Light accompanies intense heat. Air heated
up to 9009 Fahr. and made to fall on pieces of metal, earth, &c. communicates
to them the power of radiating light. The flame exhibited in the burning of
charcoal and phosphorus is merely the ignition of the solid particles of these
bodies. At a certain elevation of temperature, about 8000 of Fahr., all solid
|bodies begin to give out light, and the same effect is produced in vacuo by
transmitting voltaic electricity through a metallic wire. The phosphorescence
of minerals is another source of light. If fluor spar be coarsely pounded and
placed upon a mass of iron heated below redness, it will give out a beautiful
green light; this property is possessed by quartz, topaz, phosphate of lime, and
a variety of other minerals. There is also a class of bodies called solar
I hosphoric, which emit light upon exposure to any highly luminous body; the
most powerful of these is a compound discovered by Canton. If three parts of
calvined oyster shells in powder are mixed with one of flour of sulphur, and
the mixture rammed into a crucible, and ignited for half an hour, we shall find
that the bright parts, on exposure to the sun-beam, or to the common daylight,
or to an electric explosion, will acquire the faculty of shining in the dark so as
to render visible the figures on the dial-plate of a watch. After a while they
will cease to shine; but if the powder be kept in a well corked phial, a new
exposure to the sun-beam will restore the luminescence. When an electric
discharge is transmitted along the surfaces of certain bodies, a somewhat durable
phosphorescence is occasioned; thus—
Sulphate of barytes gives a bright green light.
Acetate of potash ... brilliant green light.
Succinic acid . . . . . ditto, more durable.
Loaf sugar . . . . . ditto.
Selenite . . . . . . . ditto, but transient.
Rock crystal . . . . . red, and then white.
Quartz . . . . . . . dull white light.
Borax . . . . . . . . faint green light.
Boracic acid . . . . . bright green light.
Canton's pyrophorous produces more light by this treatment than any other
body, but 3. every native mineral, except metallic ores and metals, become
luminous by an electric explosion. Light is also emitted in certain chemical
changes, where no sensible heat is perceived. Marine animals, both living and
dead, emit light; as the shell fish called pholas, the medusa phosphorea, and
other molluscae. When deprived of life, marine fishes in general seem to abound
in this kind of light; among insects, also, several species of fulgora, or lantern-
fly, and of lampyris, or glow-worm. Rotten wood and peat earth also emit light
copiously. This luminous matter may be separated from the bodies of animals
by immersing them for a short time in dilute saline solutions; one part of
sulphate of magnesia in eight of water is the most convenient menstruum for
this purpose. Fresh water, spirit of wine, and dilute acids, destroy the luminous
property altogether, while a gentle heat, and oxygen gas, increase the brightness
of the phosphorescence.
The next important agent in chemical investigations is heat. Many chemists
have considered heat or caloric as a material substance, capable of entering into
combination with all other kinds of matter; but recent investigations seem to
put it and light upon the same ground, and show them to be but certain states
of matter, brought about by the undulations of an exceedingly subtile ether,
which is considered to fill all the space in the universe not occupied by other
matter. Heat appears to be an antagonist principle to attraction; while the
latter binds together, the former tends to separate, the parts of bodies, first
expanding them, then reducing them to the liquid state, and finally to that
of gas or vapour. Sometimes it decomposes a body, separating it into its
proximate or ultimate elements: so powerful, indeed, is heat, as a repulsive
CHEMISTRY. 349
agent, that there can be no doubt that, if the temperature of the globe were
sufficiently increased, every solid mass on its surface would become liquid, and
every liquid assume the state of vapour. We have an illustration of this con-
sequence in the different states of the same body on different parts of the earth's
surface. Thus some bodies, as butter, oil, water, &c. which exist only as solids
at the poles of the earth, are perfectly liquid at the equator. Ether, which is
a liquid in this latitude, can only exist as a vapour in the torrid regions of the
earth. Mercury also, which we see always in the liquid state, may, by
exposure to the intense cold of a northern sky, be converted into a solid
metal like lead. The most immediate and general effect of heat is expansion.
If a poker or an iron ball be placed in a fire, it becomes heated, and assumes that
state which is called ignition; at which time its temperature is nearly equal to
that of the surrounding fuel. . In like manner, if a cup of cold water be placed
within a vessel of hot water, the two speedily become of the same temperature,
the one giving out caloric, and the other receiving it. If now either of these
bodies that have changed their temperature be examined, it will be found to have
changed its bulk also. This expansion of bodies by heat, and their consequent
contraction by cold, are facts of the highest importance in the arts. The amount
of expansion in different substances by a known increase of temperature, has
therefore been carefully studied, and a variety of results, more or less accurate,
have been obtained by different experimentalists. The property of expansion
by heat, and contraction by cold, appears to belong to nearly all bodies upon
which experiments have been made; at least in that class of bodies which com-
pose the mineral kingdom, for among vegetables the effects of heat are so
mixed with other effects, that it is difficult to distinguish them. Some minerals,
too, as clay, and several metallic substances, have been considered as excep-
tions to the general law; but a more minute investigation has shown that they
are only apparent. Clay contracts in consequence of the expulsion of mois-
ture, and the incipient fusion that occurs; and some of the metals, as iron,
bismuth, antimony, in fusion, expand in the act of setting or solidifying, but
afterwards contract as they cool. The force with which bodies expand is so
great as to overcome every resistance that is opposed to it. The general fact
of the expansion of solid bodies by heat may be
seen by taking a metal cylinder a b that will just
fit into a gauge c d, and pass through a circular
hole e when cold. When made red hot, it will
be found so much enlarged as to be incapable of 2-
passing through the hole, or fitting into the Wº
gauge, thus proving that it has been enlarged in
all its dimensions. The cubic or solid expan-
sion is always three times greater than the
linear. For example, if the expansion of a rod
of steel be one-tenth of its length, the whole
expansion will be three-tenths of its bulk. The
expansion of liquids may be made evident by filling a Florence flask, or an
bottle with a narrow neck, with cold water, and then applying heat to it; the
fluid will soon be observed to flow over the mouth of the bottle in consequence
of its increased bulk. This fact is also familiarly illustrated by means of an
ordinary tea-kettle, which, if it be quite filled with cold water, will be unable to
contain the increased bulk occasioned by heat, and will consequently discharge
a portion of its contents over the hearth long before the water reaches its
boiling point. The expansion of air may be shown by a similar apparatus. If
the flask full of air be inverted with its mouth under water, and the flame of
a lamp or candle be applied to it, the air will be expanded, and will be seen
escaping from the mouth of the flask in large bubbles. If the flame be
removed, the air will cool, gradually contract its dimensions, and the water
will rush up into the vessel to fill the space vacated by the air. The expansion
of solid bodies is ascertained by what is called a pyrometer, for the construction
of which see its name. The most general facts connected with expansion are
as follows:–1. Nearly all solids, liquids, and gases, are expanded by heat, and
Y Y
!

350 CHEMISTRY.
contracted by cold; and of these, the gases are most expansible, and solid
bodies least. 2. Different solids and liquids are differently expanded by the
same degree of heat, but gases and vapours are equally and equably expanded
by equal portions of heat. 3. In the same body, whether solid or liquid, the
expansion by a given quantity of heat, is greater at higher than at lower tem-
peratures; but in gases and vapours, the expansions are equal, by equal addi-
tions of heat at all temperatures. 4. The expansion of atmospheric air, gases,
and vapours, not in contact with the liquids from which they have been gene-
rated, is equal to one four hundred and eightieth part of the bulk they occupy at
32° of Fahrenheit's thermometer. The absolute dilatation in length of several
of the most generally used substances, is shown in the following table:—
1 I
Glass tube . IT48 Brass . . . 535
Platina 42 –– | * © * * 4: _J_
IHI Silver 524
Iron . . _1 | Tin __
846 462
Steel . . . . . . . . . Lead +
807 351
Gold . . . . _1 | Zinc . . . . 1
682 340
Copper _1_
pp 582
I
Glass from 320 to 2120 of the thermometer . . . . TT5
Ditto 212 to 392 . . . . . . . . . . . T0so
Ditto 392 to 572 . . . . . . . . . . . 957
Eagansion of liquids in bulk.
l
Apparent expansion of
mercury in glass . . . .
-64
Sulphuric ether
Alcohol . . . . . . . . Muriatic acid (sp.gr. 1.137) #
Nitric acid (sp. gr. 1.4) # Water saturated with salt #
Fixed oils # Water . #
Oil of turpentine * Mercury *
I
I4
I
E7
Sulphuric acid (sp. gr. 1.85)
One of the most important applications of the expansibility of liquids, is in
the construction of the thermometer, which consists essentially of a closed tube,
containing a liquid, the expansion of which can be conveniently observed. To
construct a thermometer, a glass tube of very small bore is usually taken, and
, a bulb, globular, cylindrical, or conical, is blown at one end, which bulb and
part of the tube are then filled with perfectly pure mercury. The tube must
then be hermetically sealed by melting the top by means of a blow-pipe flame.
Previous to closing the top, however, the mercury must be exposed to heat so
as to completely fill the tube; and while the tube is full, the sealing must be
effected. When the mercury cools, the surface will subside, and a vacuum will
be left in the upper part of the tube. The thermometer is then complete,
except its graduation; this is accomplished as follows:—The bulb is to be lunged
into snow or ice that is just melting, and a mark made on the tube at th. point
at which the mercury stands; this is called the freezing point; and in the thermo-
meters common in this country, called Fahrenheit's (from the inventor's name),
it is marked 329. The tube must next be placed in boiling water, or its steam,
in such a way that the whole of the mercury may be exposed to heat. When
the mercury has risen and is stationary, another mark must be made; this
denotes, the boiling point of water, and is marked 2129. The space between
the boiling and freezing points must next be divided into 180 equal parts, and
the graduation is complete. In the centigrade thermometer used in France,
the freezing point is marked 09, and the boiling point 100°, the intervals being
CHEMISTRY. 351
divided into 100 equal parts or degrees. One degree of Fahrenheit is there-
fore equal to four-ninths of the centigrade; and one of the centigrade to nine-
fourths, or 240 Fahrenheit. This is but a brief and general view. For further
information, see THERMOMETER.
It has been already stated that fluidity is the result of heat. Every solid
may be liquefied; and many of them, as well as liquids, may be vaporized at
a certain elevation of temperature; and there can be little doubt that every
known liquid may be solidified if we possessed the means of sufficiently
reducing the temperature. Several of the gases, by the united operation of
cold and pressure, have already been reduced to the fluid state, and nearly every
known liquid may be frozen. The temperature at which a solid body assumes the
liquid state is called its fusing or melting point. If the substance be ordinarily
in the liquid state, this point will be its freezing, concreting, or congealing point.
The concreting or congealing temperatures of various substances will be found
in the following table :-
Deg. Deg.
Sulphuric ether . . . . . 46 Sulph. and phos., equal parts 40
Liquid ammonia . . . . 46 Sulphuric acid (sp. gr. 1.78) . 46
Nitric acid (sp. gr. 1.424) . 45.5 | Tallow . . . . . . . 92
Ditto (sp. gr. 1.329) . 2.4 Phosphorus . . . . . . 108
Sulphuric acid (sp. gr. 1.8376) 1 || Spermaceti . . . . . . 112
Common salt 25 + water 75 . 4 || Potassium . . . . . . 136.4
Ditto 22.2 + ditto 77.8. 7.2 || Yellow wax . . . . . . 142
Oil of turpentine . . . . 14 | White wax . . . . . . 155
Strong wines . . . . . . 20 | Sodium . . . . . . . 194
Blood . . . . . . . . 25 Sulphur . . . . . . 218
Common salt 4.16+ water9.584 27.5 | Tin . . . . . . . . 442
Milk . . . . . . . . 30 || Bismuth . . . . . . . 476
Water . . . . . . . . 32 Lead . . . . . . . . 612
Olive oil . . . . . . . 36 Zinc . . . . . . . . 680
The temperature at which bodies melt is fixed, but the congealing point is
modified by circumstances. Many liquids may be cooled considerably below
their usual freezing points, before they assume the solid state. This is the case
with water, which may be cooled 10°, or even 20° below its congealing point
without freezing; but if a small spicula of ice be dropped into it, or the water
caused to vibrate, it will instantly solidify. The same phenomena occur with
saline solutions. A hot saturated solution of sulphate of soda may be cooled
to 50” under a film of oil, and it will remain liquid, and bear to be moved
about in the hand without any change; but if the vessel containing it be placed
on a vibrating table, crystallization will instantly take place. One remarkable
fact attends the cooling of bodies below their usual freezing point; viz. at the
instant solidification occurs, the temperature of the mass rises to the proper
freezing point. Thus, if a portion of water be placed in an atmosphere of 219,
the liquid will cool and remain fluid at this temperature, till, by touching it
with a piece of ice, or causing it to vibrate, we make it freeze, when it instantly
rises to 320, or 110 above the surrounding medium. This curious fact was first
explained by Dr. Black, and gave rise to the knowledge of the latent heat or
caloric of fluidity of bodies. Dr. Black suspended two glass globes, of the same
size, near each other; the one filled with ice at 32°, the other with water at
330: in half an hour the water had risen to 400, but it took ten hours and a
half to liquefy the ice, and heat the resulting temperature to 409. In this
experiment we observe that 7° of heat entered the globe in 1 half-hour, but
21 half-hours were required to melt the ice and raise its temperature to 40°.
If from the product 7 × 21=1479, we subtract 79, which the water was above
330, we have 1400 as the measure of a quantity of heat that has entered the sub-
stance without being appreciable by the thermometer. Another simple experi-
ment, showing the same result, is made by mixing a pound of pulverized ice
at 320, with a pound of water heated to 172°; the ice is instantly melted, but
the temperature is only 329. Here, then, 140° of heat have disappeared with-
out raising the temperature. From this circumstance, the quantity of heat that
352 CHEMISTRY.
always disappears when a body assumes a fluid state, is called latent heat, or
caloric of fluidity. The latent heat of different substances varies, as may be
seen in the following table by Dr. Irvine:—
Sulphur . . . . . . 143.68 Zinc . . . . . . . 493
Spermaceti . . . . 145 Tin . . . . . . . 500
Lead . . . . . . 162 Bismuth . . . . . . 550
Bees' wax . . . . . 175
The quantity of heat that disappears in the liquefaction of solids, explains the
origin of that cold which always accompanies solution, and enables us to apply
the process of artificial cooling by what are termed freezing mixtures. Snow
and salt, when rapidly mixed, dissolve and produce a reduction of temperature
equal to 38°. The more rapid the liquefaction the greater the cold ; hence, if
the snow and salt be placed in a pan over the fire, and a glass tube containing
water be immersed in it, the water in a few seconds will be found frozen. The
solution of all crystallized salts is attended with a depression of temperature,
which in general increases with the solubility of the salt; the like occurs with
certain metals. If a solid amalgam of bismuth be mingled with a solid amalgam
of lead, they become fluid, and the thermometer sinks. A variety of experiments
have been made on the frigorific effects of different mixtures, some of which
are stated in the following table, abridged from Mr. Walker's Eageriments on
Frigorific Mixtures.
1. Frigorific Mixtures without Ice.

Degree
Mixtures. Parts. Thermometer sinks, of cold
- - - - produced
Muriate of ammonia * @ 5
Nitrate of potash . . . 5 From 50c to 100. 40
Water : . . tº gº º 16 . - -
| Sulphate of soda . . . . 3 * * * : . . . . . .
{ Diluted nitric acid . * 2 From 50 to 3. 53
Nitrate of ammonia . 1 From 50 to 4. 46
Water . . . 1.
Sulphate of soda. .e. . e. 5 50 to 3 47
Diluted sulphuric acid . . 4. From 50 to 3.
2. Frigorific Mixtures with Ice.
Snow or pounded ice . 2 From any temperature to 5.
Muriate of soda . . . . 1
Snow . . . . . . . . 7 From 32 to 30. 62
Diluted nitric acid . 4.
Snow . . . . . . . . . 4. From 32 to 40. 72
Muriate of lime . . . . 5 *º-
Snow • . . . . 2 From 15 to 68. 53
Muriate of lime . 3
Snow . . . . . . . 8 F 68 to 91. 23
Diluted sulphuric acid . . 10 TOIſl
Similar phenomena to those that take place in liquefaction, occur in vapor-
izing any fiquid. If a vessel of water be placed over the fire, a sound is pro-
CHEMISTRY. 353
duced by the successive vaporization and condensation of the particles in
contact with the bottom of the vessel. As the liquid increases in heat, the
sound becomes louder till it terminates in ebullition. At this point the tem-
perature ceases to rise, and remains stationary till the whole of the liquid is
evaporated. To ascertain the quantity of heat consumed in vapourizing a
given quantity of water, Dr. Black set a tin cup full of water at 50° on a red
hot iron plate; in 4 minutes it reached the boiling point, and in 20 minutes
more it was all boiled off. From 500 to 212° the rise is 162°, which was gained
in 4 minutes; but it took five times as long to be converted into vapour; hence
162 × 5=810° is the quantity of heat that disappears, or is rendered latent in
the conversion of water into steam. By subsequent experiments, the latent
heat of steam is found to be 967°, or 1,000°. The point at which liquids emit
vapour of equal tension with the atmosphere, which is their true boiling point,
differs in different liquids, as may be seen in the following table:—
Boiling points.
Ether (spec. grav. 0.7365, at 48%) . . . . . . 100
Alcohol (spec. grav. 0.813) . . . . . . . . 173.5
Nitric acid (spec. grav. 1.500) . . . . . . . 210
Water . . . . . . . . . . . . . . . 212
Saturated solution of sea salt . . . . . . . 224
Muriatic acid (spec. grav. 1.094) . . . . . . 232
Ditto (spec. grav. 1.16) . . . . . . . . . 220
Oil of turpentine . . . . . . . . . . . . .316
Sulphuric acid (spec. grav. 1.3) . . . . . . . 240
Ditto (spec. grav. 1.848) . . . . . . . . . 600
Phosphorus . . . . . . . . . . . 554
Sulphur . . . . . . . . . . . . . . 570
Linseed oil . . . . . . . . . . . . . 640
Mercury . . . . . . . . . . . . . . 656
The boiling point of the same liquid varies with the atmospheric pressure, and
also with the vessel the liquid is boiled in. Thus, in silver, the boiling point
was found to be 211.775°, in common earthenware, 213.8°, at the mean pressure
of the atmosphere. If the whole of the pressure be removed, liquors will boil
and assume the vaporous state at 124° below their ordinary boiling points.
Thus water will boil in vacuo at 88°, instead of 212° ; and alcohol, at 49°. On
this principle Dr. Wollaston constructed his thermometric barometer, for mea-
suring heights. He found that a difference of 1° in the boiling point of water
is occasioned by a difference of pressure equal to 0.589 of an inch on the
barometer. If water be heated in a close vessel, or under extraordinary pres-
sure, its temperature may considerably exceed 2120; and as the steam will be
always of the same temperature as the liquid, and will have its elasticity
increased by heat, the vapour produced will considerably exceed the atmo-
sphere in elasticity, giving rise to what is called high pressure steam. At the
freezing point of water, the vapour that rises will have sufficient elasticity to
balance two-tenths of an inch of mercury in the barometer; at 212° it equals
the atmospheric pressure (about 30 inches). Its elasticity at some other tem-
peratures is stated in the following table:—
Temperature. Pressure.
. . . . . 0.25 inches.
80 . . . . . . . . 1.01
100 . . . . . . . . 1.86
135 . . . . . . . . 5.07
170 . . . . . . . . 12.05
205 . . . . . . . . 25.00
212 . . . . . . . . 30.00 = 1 atmosphere.
248 . . . . . . . . 60.00 =2 diuto.
273 . . . . . . . . 90.00 =3 ditto.
290 . . . . . . . . 120.00 =4 ditto.
305 , . . . . 150.56=5 ditto.
3.54 CHEMISTRY.
A pint of water at 400, on being converted into steam, forms 1,694 pints; or
in round numbers, 1 cubic inch of water will form 1,728 inches, or 1 cubic
foot of steam. We have already observed that the latent heat of steam is about
1,000°. This may be ascertained by evaporating a given weight of water, and
condensing it into a known weight
of cold water. This may be illus-
trated by an apparatus similar to
the annexed cut. A given weight
of water may be evaporated from
the vessel a, the vapour of which
will pass along the pipe c, and be
condensed in the water in b. It
will be found that the steam will
raise the temperature of the
water in b six or seven times
more than an equal weight of
boiling water would do. By ex-
Fº in this manner, Dr.
re has ascertained the latent
heat of several vapours, as in the annexed table:—
Latent heat.
Vapour of water at its boiling point . . . . 1000
35 alcohol (spec. grav. 825) . . . . 457
35 ether (boiling point 112) . . . 312.9
}} petroleum . . . . . . 183.8
35 oil of turpentine . . . . . . 183.8
33 nitric acid (spec. grav. 1.494) . . 550
35 liquid ammonia (spec. grav. 0.978). 865.9
33 vinegar (spec. grav. 1.007) . . . 903
From the above table it will be seen that different bodies require different
quantities of heat to enable them to assume the vaporous state. An analogous
fact is, that different bodies require very different quantities of heat to elevate
their temperatures a given number of degrees. If a pound of water at 600 be
mixed with a pound of oil at 90°, the resulting temperature will be 70° instead
of the mean 750. And conversely, if a pound of water at 90° be mixed with
a pound of oil at 60°, the temperature of the mixture will be 80s. In the first
experiment we see that the oil lost 20°, while the water only acquired 10°; and
in the second the oil gained 20°, while the water lost only 10°. Hence the
specific heat of water is double that of oil; or the same quantity of heat that
will raise the temperature of oil 20°, will only raise that of water 10°. The
same fact may be shown by placing mercury, oil, and water, in an oven; the
mercury will be first heated, next the oil, and lastly, the water. An important
practical illustration of the doctrine of specific heat is afforded by atmospheric
air. The specific heat of air diminishes more slowly than its specific gravity.
When air is expanded to a quadruple volume, its specific heat is 0.540; and
when expanded to eight times the volume, its specific heat is 0.368. The den-
sities 1, 3, 3, #, correspond nearly to the specific heats 5, 4, 3, 2. Hence may
be explained the intense cold that prevails at the tops of high mountains, and
also the great heat developed in the compression of gases. A compression
equal to four-fifths is sufficient to ignite tinder; and if a syringe of glass be
used, a vivid flash of light is seen to accompany the compression.
We have now alluded to most of the phenomena of heat that may be useful
in chemical investigations, except those which relate to the conduction and
radiation, which we shall briefly illustrate.
It is well known that if a bar of iron, as a poker, be placed in the fire, the
heat will in time be communicated to its remote end. It is also a matter of
common observation, that a hot mass of iron, or a vessel of hot liquid sus-
pended in a room, will gradually become cooler until it attains the temperature
of the surrounding medium. If we suppose a mass of iron, heated red hot, to

CHEMISTRY. 355
be placed on a metallic pillar or support, it
will lose its heat in three distinct ways. 1. If the metallic support be felt, it
will be found to be hot, and we may consequently infer that a portion of the
heat has been conducted away by its means. 2. If the hand be held over the
hot body, considerably above it, a current of hot air will be perceived, which
must convey another portion of caloric from the hot body. 3. If the hand be
held at some distance from the side of the body, a distinct sensation of heat will
be experienced; and as this occurs when the hot body is inclosed in a vessel
exhausted of its air, it is manifestly a different mode of cooling from the other
two: in fact, a variety of experiments render it evident that the heat is pro-
jected from the hot body in right lines on every side. In the first of these
modes of cooling, the heat is conducted slowly along the iron bar, which is
denominated a conductor ; and the process is called the conduction of heat.
In the second, the heat unites with the particles of air, and renders them speci-
fically lighter, in consequence of which they ascend, and another stratum of
cooler particles descend and occupy their place; these in their turn become
expanded and rise, and thus a constant ascending current is maintained.
Caloric, therefore, is conducted from bodies in two ways; it either imparts heat
to the adjacent particles, which impart it to the next, and so on, without change
of place, or it unites with the adjacent particles of the surrounding medium,
and is conveyed upwards by the increased levity which it occasions. The third
method of cooling in which the caloric is projected from the body in right
lines, is called the radiation of caloric. The communication of heat by con-
tact is manifest in solids and liquids, although in the latter it is chiefly propa-
gated by the ascent of heated particles. If different solids be taken, and have
one end exposed to a high temperature, one of them will become heated in a
shorter time than another. Thus, if a piece of copper or iron wire, 3 or 4
inches long, be held in the hand by one end, while a spirit lamp is applied to
the other, it will soon become so hot as to be intolerable; while a glass tube, in
similar circumstances, may be held within an inch of the flame with little
inconvenience. The difference in the facility with which heat is transmitted
through bodies, will appear from the following table:–
a still room, we shall find that it
Conducting power. Conducting power.
Gold . . . . . 100 Tin . . . . . , 30
Platinum . . . . 98 Lead . . . . . . 18
Silver . . . . . 97 Marble . . . . . 2.5
Copper . . . . . 89 Porcelain . . . . 1.25
Iron . . . . . . 37 Brick earth . . . 1
Zinc . . . . . . 36
From this table it appears that the metals are the best conductors of heat,
though even among them there are striking differences. The different kinds
of wood have very little conducting power, and hence are well adapted for
handles to vessels that are exposed to heat. Bodies of a porous or spongy
nature, especially fibrous substances, as wool, silk, feathers, fir, &c. are the worst
conductors of heat; and from this circumstance derive their value as articles of
clothing. It is, however, probable that the warmth of these substances is
attributable rather to the impediments they offer to the motion of the air than
from any inherent heat-retaining power. Confined air is a bad conductor of
heat; and if a quantity of it be enclosed among the interstices of the fur,
wool, &c, it will furnish an effectual barrier to the egress of caloric. On this
account double windows and doors are found effectual in maintaining an equable
temperature in our apartments. The conducting power of liquids by contact is
so exceedingly small, that for a long time it was doubted whether they conducted
at all. Accurate experiments made in vessels of ice, have, however, established
the fact that liquids do conduct heat downwards, or by contact of their particles.
If it be desirable to heat a liquid, it is well known that the heat should be
applied at the bottom of the vessel, by which means the stratum of particles
nearest the fire becomes lighter, and ascends, being forced up by the descent of
356 CHEMISTRY.
the colder, and therefore heavier parts. This process continues until the whole
has attained that degree of heat at which the É. boils; the same occurs in
heating a confined portion of air. Any circumstance that tends to impede the
motion of the particles of liquids will diminish the facility with which they are
heated or cooled. Water-gruel, soups, and other thick drinks, retain their heat
for a considerable time; while more dilute liquids become cooled at the surface,
the cooler parts subside, and the hot ones rise and come into contact with the
atmosphere; these become cooled and sink, and thus the process goes on till the
whole attains the same temperature as the surrounding medium. It has been
long known that the sun's rays proceed in right lines, and that they are capable
of being reflected and refracted by mirrors and lenses so as to produce an intense
heat. In like manner, if an iron ball be heated a little below redness, it will
be found to emit rays of heat that are capable of being reflected and re-
fracted in a similar way. If two concave and polished metallic mirrors
be placed opposite to each other, and at about eight or ten feet distant,
(as in the annexed engraving,) and the hot iron ball be placed in the
focus of one, as at a, while in that of the other we place a piece of phosphorus
b, resting on a lump of charcoal, or any bad conductor, in a few seconds the
phosphorus will inflame. Now to produce this effect, it is manifest that rays
of heat must have emanated from the iron ball, and falling on the nearer
mirror, must have been reflected to the second mirror, by which they have been
concentrated on the phosphorus. In this experiment we observe two important
facts, the radiation and reflection of heat. Radiation may be considerably
modified so as to be nearly destroyed by an alteration of the surface of the
radiating body. Instead of the hot ball, Sir John Leslie used a tin cubic
cannister filled with hot water; and as a large body would stop the return of
the rays, he used only one mirror, in the focus of which he placed one of the
balls of his differential thermometer, as here represented. Previous to placin
the cubic canister a before the mirror b, its four vertical sides were coated wit
different substances—one with lamp-black, another with China ink, a third with
isinglass, while the fourth was left naked, presenting a surface of polished tin.
When this yessel, filled with hot water, was presented to the mirror, the ther-
mometer c immediately indicated an increase of temperature, varying according
to the surface presented; the lamp-black surface depressed the liquid of the


CHEMISTRY. 357
thermometer 100°, the China ink 88°, the isinglass 80°, and the tin 12°. By a
variot ºr of c: no slav experiments Professor Leslic obtained the results in ihe foi-
* * * * * * * * * * * *-*.*.*.*.*, *, *.*.*.* ~~f~ ** --~~~~~~ 3 - * ~ *
lowing table:—
Radiating power. Radiating power.
Lamp black . . . . 100 Isinglass . . . . 80
Water (by estimate). 100 Plumbago . . . . 75
Writing paper . . . 98 Tarnished lead . . 45
Resin . . . . . . 96 Mercury . . . . 20
Sealing wax . . . 95 Clean lead . . . . 19
Crown glass . . . 90 Iron polished . . . 15
China ink . . . . 88 Tin plate . . . . 12
Ice . . . . . . 85 Gold, silver, copper . 12
The nature of the substance is not the only circumstance that influences
radiation. In general, the more smooth and polished the surface, the more
feeble in its radiating power. If the surface be roughened with a file, or other-
wise, its radiation is increased. It also appears that the radiation occurs not
only from the superficial particles, but also from those immediately beneath
them. With one coating of jelly it was found that the radiation was 38° ;
while a film of the same substance, four times thicker, produced a depression
of 54°. When the thickness of the coating amounted to one-thousandth part
of an inch, the radiation became diminished. If the same radiating surface
be presented to different mirrors, we shall discover the differences in the
reflective powers. By various experiments of this kind, the reflective powers
of several substances were found to be as follows:–
Reflective power. Reflective power.
Brass . . . . . 100 Tin foil softened with
Silver . . . . . 90 mercury . . . . 10
Timfoil . . . . . 85 Glass . . . . . 10
Black tin . . . . 80 Ditto coated with wax
Steel . . . . . 70 or oil . . . . .
Lead . . . . . 60
If we compare these tables, we shall find generally that the best radiators are
the worst reflectors, and vice versä. It may easily be inferred, that those bodies
that radiate most caloric, when heated above the temperature of the surround-
ing medium, will also absorb most rapidly when exposed to a temperature supe-
rior to their own. In the experiment with the lamp-black surface exposed to
the mirror, the thermometer indicated a temperature of 100°; if, however, the
glass ball of the thermometer be covered with tin foil, the indication will be re-
duced to 20°. In the same manner, if the bright side of the canister be pre-
sented, the temperature will be 12°, but with the bulb covered, only 23°. From
these experiments, as well as from reasoning, it is evident that the absorptive
power is equal to the radiating. Connected with this part of the subject is the
effect of screens. When a thin deal board was placed between the canister
and the focal ball, the thermometric effect was diminished, and this diminution
was proportional to the thickness of the screen. A pane of glass interposed
reduced the effect of radiation from 100° to 20°. The reduction was greatest
when the screen was most distant from the canister: the thinnest gold leaf
stopped the whole of the heat; in general, those bodies intercept heat most
effectually which are the worst radiators. From some more recent experiments
of M. de la Roche, it is found that caloric acquires a more penetrating power
as it proceeds from a source of higher temperature. A curious experiment was
made by the Florentine Academicians, in which, instead of the hot canister,
a large mass of snow was placed before the mirror: in this case the ther-
mometer indicated a rapid depression of temperature, and it was at first
inferred that rays of cold emanated from the snow and acted on the ther.
mometer; this supposition is, however, unnecessary, for it may easily be shown
that all bodies radiate heat constantly. Even a mass of ice or snow may have its
temperature higher than the surrounding air, and will, therefore, produce signs
Z Z
358 CHEMISTRY.
of heat in the thermometer. In the experiment just cited, the snow radiates
caloric towards the mirror, and the thermometer, at the same time, radiates
towards it, which is reflected towards the snow. If the snow were not placed
in front of the mirror, the thermometer would receive as much caloric as it
emits, and hence its temperature would remain constant; but as the temper-
ature of the snow is lower than that of the thermometer, the latter receives less
than it imparts, and its temperature falls.
Having stated the most important general facts connected with heat, we
must refer the reader to other articles in the work for more particular infor-
mation, under the words ExPANsion, THERMoMETER, PyRoMETER, CoMBustion,
&c. and proceed to another important agent in chemical research—electricity.
If a glass tube, or a stick of sealing-wax, be briskly rubbed with a dry silk
handkerchief, and then presented towards small pieces of paper, feathers, or
gold leaf, it will first attract and then repel them. Or if a glass tube be taken
in one hand, and a stick of sealing-wax in the other, and each be rubbed, then
if the glass rod be brought near a piece of gold leaf floating in the air, it will
first attract, and afterwards repel it. While the gold leaf is repelled by the
excited tube, if the sealing wax be brought near, the leaf will be attracted, and
thus it will be seen that bodies electrified by glass will be attracted by the wax,
and vice versá, Bodies that are electrified by glass are said to be positively or
vitreously electrified; and bodies submitted to excited wax are called negatively,
or resinously electrified. If either of the tubes are well excited, and a finger
be presented to it, a crackling noise will be heard, and in the dark, sparks of
light will be seen issuing from the tube; these are termed electric sparks. If
to the further end of the excited tube a brass ball be attached by a wire, the
ball will possess all the qualities of the tube itself; but if it be connected by
means of silk, the electric virtues will not pass into it. From this circumstance
bodies have been divided into conductors and nonconductors. Some bodies
conduct or permit the passage of electricity more readily than others; hence
arises the distinction of good and bad conductors. The following table contains a
list of conducting substances in the order of their conducting power.
Copper. Dilute acid.
Silver. Saline solutions.
Gold. Animal fluid.
Iron. Water.
Tin. Ice and snow above 0°.
Lead. Living vegetables.
Zinc. Living animals.
Platinum. Flame.
Charcoal. Smoke.
Plumbago. Vapour.
Strong acid. Salts.
Soot, and lamp black. Rarefied air.
Metallic ores. *. Dry earths.
Metallic oxides. Massive minerals.
The nonconductors or insulators are as follows:—
Shell lac. Dry paper and leather.
Amber. Dry woody fibre.
Resins. Porcelain.
Sulphur. Marble.
Wax. Massive earthy minerals.
Asphaltum. Camphor.
Glass, and all vitrified bodies. Caoutchouc.
Raw silk. Dry chalk and lime.
Bleached silk. Phosphorus.
Dyed silk. Ice (below 0° Fahr.)
Wool, hair, and feathers. Oils; the densest are the best.
Dry gases. Dry metallic oxides.
CHEMISTRY. 359
* * * * *-* * * * * * * *** A tº * *-* * * * *----- *** - - * * * - * * - * * *-* * * - ºr sº-
whole list, from copper to shellac, might be considered as one series, in which
different degrees of resistance are opposed to the passage of electric power.
The best conductors are sometimes called nonelectrics, and the best insulators
electrics, on the supposition that only the latter were capable of producing
electricity by friction. This appears to be erroneous, as even metallic bodies
may be excited if they are held by a nonconductor to prevent the electricity
being carried away as soon as produced. A similar mistake was originally
made with respect to the production of vitreous or resinous electricity. It was
thought that the same body always produced the same kind of electricity; but
1t is now known that this depends on the nature of the rubber. In all cases
where two bodies are rubbed together, if the one become vitreously electrified,
the other will be resinously electrified. In the following table the several sub-
stances acquire vitreous electricity when rubbed with those which follow them,
and resinous when rubbed with those that precede them : —
The skin of a cat. Paper.
Polished glass. Silk.
Woollen stuff, or worsted. Lac.
Feathers. Roughened glass.
Dry wood.
The early experimenters used only the glass tube for the excitation of elec-
tricity; but the labour and insufficiency of this process soon gave rise to a
machine for the same purpose.
There are two kinds of elec-
trical machines now in use,
which are called the plate ma-
chine, and the cylinder machine.
The cylinder machine is shown
in the annexed figure, in which
a is a cylinder of glass, mounted
in a frame, so as to be turned on
its axis by means of the handle
f. At e is a cushion stuffed with
wool or horse-hair, and covered
with an amalgam of three parts
of mercury, two of zinc, and
one of tin, melted together.
Attached to the cushion is a lº
piece of silk c, which reaches
over the cylinder as far as the
prime conductor b. The prime
conductor b is a cylinder of e ©
tin or brass, mounted on a glass leg d, and furnished with a row of points ex-
tended towards the cylinder, for the purpose of collecting the electricity gene.
rated by the friction of the cylinder against -
the rubber. The cushion is mounted on a glass
leg for the purpose of procuring resinous elec-
tricity; but when only vitreous electricity is
required, a chain or piece of wire must be ſ
attached to the cushion. The principle of the ###
plate machine is precisely similar to this; but, j
instead of a cylinder, a circular glass plate is
mounted, so as to turn on an axis passing tº
through its centre, while the rubbers are applied fi
near its circumference. When a greater quan- ;
tity of electricity is required than can be fur-
nished by sparks from the prime conductor,
an apparatus is used, which, from having been
discovered at Leyden, is called the Leyden Jar. In the engraving a represents
w #
:lº-
º
|
º






36U CHEMISTRY.
a glass jar coated within and without with tin foil, except near the top; b is a
brass ball connected with the interior coating by means of a brass wire. When
the knob b is brought near the prime conductor of the electrical machine, sparks
pass into the jar, until it has become charged. A discharging rod c, furnished
with a glass handle d, is then applied, so that one ball touches the outer coating,
and the other the brass ball b; the whole of the electricity then passes from the
inside to the outside of the jar, which is then said to be discharged. If, instead
of the discharging rod, a person applies his hands to the outer and inner sides
of the jar, the electricity passes through him, and he receives an electric shack.
If the electricity be accumulated in a large jar, or if several jars are connected,
as in the accompanying sketch, they form an electric battery, and all the effects
produced by lightning may be imitated by means of it. If electricity be passed
through resin, phosphorus, ether, gunpowder, &c. it inflames them ; it will
penetrate a thick card or a quire of paper; and if in sufficient quantity, will
destroy life in an eel, rabbit, dog, &c. Friction is not the only means of pro-
ducing electric indications, but it is the most energetic; and when we have
occasion to test the presence of electricity excited by other means, it is necessary
to use a delicate electrometer. One of these, called Bennet's electrometer,
shown in the accompanying sketch, consists of two small slips
of gold leaf suspended by a brass wire within a glass cylinder.
In the improved form of the instrument the wire which carries
the leaves a a passes through a plug of silk within a glass tube
b in the cap of the electrometer. By this instrument we are
enabled to perceive that electricity is excited in the fusion of
inflammable bodies, in evaporation, in the disengagement of
gas, by the sudden disruption of a solid body, by change of
temperature, by contact of dissimilar bodies. This latter has
been considered by Volta and others as the origin of voltaic
electricity, while some of our first chemists consider chemical
action to be the primary source of voltaic energy. Voltaic elec- 6
tricity is usually procured by an arrangement of copper and Y
zinc plates, called a voltaic battery. There are different forms of
this apparatus, but the battery of Cruikshank is, on the whole, the most convenient.
This consists of a number
of zinc and copper plates,
soldered together at their
edges, and cemented into
$
* Sº |
º º
N
N
WN
Q
e e ñ iii. |####
grooves in the sides of a Fºº
º º º # º º #
mahogany trough. To #! | º | º: #####| || #
prepare the battery for ac- | | º *
Hºlº' ºr a cº-
tion, a liquid consisting of
about two parts of sul-
phuric acid, one of nitric



















































































CHEMISTRY. - 361
acid, and #66 of water, should be poured into the cells till they are nearly full; a
wire must then be inserted at each end touching the outer plates. The wire con-
nected with the zinc plate will give off positive electricity, and the wire attached
to the copper plate, negative electricity. The galvanic or voltaic battery is a
highly important agent in chemical research, both from its energetic décom-
posing power, and from the intense heat which it produces. If the two wires are
of platinum or gold, And are inserted into a glass of water, the water will be
decomposed into its elements, oxygen and hydrogen; the oxygen will appear at
the positive wire, and the hydrogen at the negative If the ends of the wires dip
into two separate glasses of water, and a finger of each hand be immersed in
them, a slight electric shock will be felt, the intensity of which will increase with
the number of plates. If the number of plates is very great, or if of large dimen-
sions, the phenomena are beautiful and striking. The battery of the Royal
Institution, used by Sir H. Davy, in his researches, contained 2,000 pairs of
plates, containing a surface of 128,000 square inches. When pieces of charcoal
about an inch long, and one-sixth of an inch in diameter, were brought within
one-thirtieth or one-fortieth of an inch of each other, a bright spark was pro-
duced, and more than half the volume of the charcoal became ignited to whiteness;
and by drawing back the points a little from each other, a constant discharge
took place through the heated air, in a space equal at least to four inches, pro-
ducing a most brilliant ascending arch of light, expanded and conical in the
middle. When any substance was introduced into this arch, it instantly became
ignited. Platinum melted in it like wax in the flame of a common candle.
Quartz, the sapphire, magnesia, lime, all entered into fusion. Fragments of
diamond, and points of charcoal and plumbago, rapidly disappeared and seemed
to evaporate in it, even when the connexion was made in a receiver exhausted
by the air pump; but there was no evidence of their having previously under-
gone fusion. Copper and zinc are not the only metals proper for forming a
galvanic battery, but they are the least expensive. The following tables by Sir
H. Davy will furnish a variety of combinations. The metal first named is
positive in reference to those that follow.
With Ordinary Acids.
Potassium and its amalgams; barium and its amalgams; amalgam of zinc.;
zinc ; amalgam of ammonium, cadmium, tin, iron, bismuth, antimony, lead,
copper, silver, palladium, tellurium, gold, charcoal, platinum, iridium, rhodium.
With Alkaline Solutions.
The metals of the alkali, and their amalgams, zinc, tin, lead, copper, iron,
silver, palladium, gold, platinum, &c.
With the Solutions of Hydro-Sulphurets.
Arrangements consisting of one Conductor and two Imperfect Conductors.
*

Solution of sulphur and potash | Copper. Nitric acid.
of potash . . . . . S.lver. Sulphuric acid.
of soda . . . . . . Lead. Muriatic acid.
Tin. Any solution contain-
Zinc. ing acid.
Other metals.
Charcoal.
The most splendid effects of the voltaic battery achieved by Sir H. Davy were
the decomposition of the alkalies and alkaline earths, as potash, soda, baryta,
strontia, lime, and magnesia. These were found to be composed of a brilliant
$62 CHEMISTRY.
wnite metal combined with oxygen, which were separated and exhibited at the
opposite poles of the battery. This mode of decomposition, arising from electric
repulsion, has afforded a convenient basis for the arrangement of the simple
substances for the convenience of study, and by its means they are divided into
two classes. The first consists of those elements which are attracted from their
compounds with substances of the other class, by the positive pole of the voltaic
pile; and as bodies in opposite states of electricity attract one another, they have
been called electro-negative bodies. The second comprises those elements that
are attracted by the negative pole, which are therefore termed electro-positive
bodies. Before giving a list of the simple substances, it will be necessary to
allude to the theory of equivalents. In an early part of this article we have
stated that different bodies combine in proportions that are fixed with regard to
each other in a given compound. We may now observe that these proportions
are definite with regard to every other substance with which they are capable
of entering into composition, so that there are certain determinate proportions
of all bodies which are equivalent to each other in their powers of combining
with all other bodies. Thus, acetate of lead is a compound of 50 parts of acetic
acid and 112 parts of lead, in the state of an oxide. White vitriol, or sulphate
of zinc, is composed of 40 parts of sulphuric acid and 41 parts of oxide of zinc.
Now these proportions are all equivalent to one another, and if the numbers are
written against the different substances as follows, we can at once perceive the
proportions in which they will unite in any new combination.
Sulphuric acid . . . . . . . . . . 40
Zinc (oxide) . . . . . . . . . . . 41
Acetic acid . . . . . . . . . . . 50
Lead (oxide) . . . . . . . . . . . 112
The same equivalent numbers or their multiples are preserved in every possible
combination with other bodies; and when any body is compounded of two
simple substances, the sum of the equivalents of the two elements will give the
number, denoting the proportion in which it will combine. Thus the prime
equivalent of hydrogen is 1, that of oxygen 8; these combine to form water,
the equivalent of which is 9. The following table contains the names of those
substances which being, in the present state of chemistry, undecomposable, are
considered as simple elementary bodies, classed in two divisions, and having
their equivalent or combining numbers attached.
Non-Metallic.
*-l
* Fqui- - * * Equi-
Electro-negative. valents. Electro-positive. Valents.
* * * Oxygen . . . . 8 Hydrogen . . 1
Aériform. {{..., • e º 'º 36 Nitrogen . . 14
Bromine . . . . 75
Iodine . . . . . 124
Volatile. e º 'º e º º º Sulphur . . . I6
e e º e º a tº Phosphorus . . 12
tº * * * Selenium . . 40
e e º e º 'º e Q Carbon . . . 6
Fixed. } tº e º e & e e Silicon . . . 8
Boron . . . 6
CHIMNEY. 363
Metallic Elements.
Electro-negative. viºl Electro-positive. vº.
tº e e º e Mercury . . 200
tº e º & & Silver . . . 1 10
| tº • *e & º Gold e º © 200
Oxides reducible by \ . . . . . Platinum . . 96
Imere heat, (noble 7726- J. tº 5 e Palladium e e 56
tals). e - e - © e Rhodium . . 44
b - is tº º e Iridium . . 7
º, e a e º e Osmium . . !
e s c e s - Nickel . . . 30
tº e º 'º as Lead . . . 104
a o º Tellurium . . 29
º e tº Copper . o 64
tº e dº Bismuth . . 71
e e e Titanium . . º
Do not decompose ' ' ' º: a & © !
water at any tempera- (" " ' tº. & © %
ture. * @ e ranium . . e
e & © Antimony . . 44
e e º 'º tº e Columbium . 144
tº º e Tungsten . . 96
e - e. Chromium . 28
º e º Gº & c. Molybdenum. 48
e e is e o e Arsenic . . 38
© e º e º e Tin . . . . 59
Decompose water at a J ' ' ' ' ' ' %. e - e. ;
red heat. tº º e tº e º 6. . . & de
© tº e tº ºr admium . . 56
e e e Manganese . 28
© tº º Potassium . . 40
Decompose water at [. © c Sodium . . 24
atmospheric temper- ) . . . Lithium . . 10
atures. Oxides, caus- ) . . . Calcium . . 20
tic, (alkaline metals.) | . . . Barium . . 70
e - © Strontium . . 44
Decompose water below e e º is tº *..." gº :
a red heat, but oxides Yttrium e e 34
insipid. (Earthy me- Aluminum e 10
tals). º º e
e e s e º 'º' Zirconium . ?
A particular description of the properties of these bodies, with the compounds
formed by their union with each other, will be found under the initial letter of
their respective names.
CHIMES. A piece of musical mechanism produced at equal intervals of
time by the strokes of a hammer against a series of bells. This is effected by
means of a chime-barrel, which is something of the nature of a barrel to an
organ. It is a cylinder of brass in small clocks, or of wood in church clocks,
which gives motion to the hammers that strike the bells, and produce a change
or tune by means of pegs inserted into certain points of its circumference at
measured intervals.
CHIMNEY. An aperture or passage for the escape of the smoke and
heated air from a furnace or fire-place, and for producing a more perfect com-
bustion by determining a rapid current of air through the fuel. The principle
upon which the action of a chimney depends, is, that the air in the chimney
364 CHIMNEY.
becoming rarefied, its specific gravity is diminished, and the weight of the
column of air within the chimney becoming less than the weight of a column
of the external air of the same altitude, the heated air in consequence escapes
at the top of the chimney, and is replaced by the colder and denser air, which
enters at the bottom. The greater, therefore, the height of the chimney, the
greater will be the effect; for the greater will be the difference in the weight of the
two columns of air. In Mr. Tredgold's workedn warming and ventilating apart-
ments, the following rule is given for the orifices of chimneys according to the
height and magnitude of the fire-places. Multiply by 17 the length of the fire-
place in inches, and divide by the square root of the height of the chimney
(above the grate) in feet, and the quotient is the area in inches for the aperture
of the chimney. Mr. Hiort, of the Office of Works, Whitehall, has taken out
a patent for a new method of building chimney flues and tunnels, which has
been adopted in the new palace, Pimlico, and in several public buildings, and
has given great satisfaction. The plan consists in building within the usual
walls, and incorporated with the common brick-work, circular smoke flues or
tunnels, as seen in the annexed plan or horizontal
section at b. Each flue or tunnel is surrounded in
every direction, from top to bottom, by cavities or
hot-air chambers c c, commencing at the back of
each fire-place, and connected with each other.
The air confined within these chambers is said to
be rendered sufficiently warm by the heat of any
one fire, to prevent condensation in all the flues con-
tained in the same stack of chimneys. The figure
of each brick composing these circular flues is
wedge-like, or inclined, as respects its upper and
lower surfaces: the external face is composed of two planes, forming a very
obtuse angle with each other; and the internal, of the arc of a circle, to the
centre of which the two ends of the brick tend or radiate; and the whole circle
is completed by placing four bricks together, end to end, as shown in the fore-
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gºing plan. Their inclined figure is best shown in the engraving above, from
which it will likewise be seen that the flues or tunnels may be carried in any




























CHIMNEYS. 365
direction without producing any internal angles, the bricks being readily
adapted to any required curvature. To make the flue straight, it will be
observed that the thick ends of one
course of bricks are placed alternately
upon the thin ends of the next course;
and in order to make curves, the thick
ends are placed together on one side,
and the thin ends on the opposite side.
The circular flue commences at the
throat of the chimney below the usual
line of the chimney bar, and imme-
diately over the fire. From below the
chimney-bar the flue is continued,
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downward to the hearth in a half-
circle, forming the centre of the back
of the fire-place. From the construc-
tion of these chimneys, and the nature
of the materials of which they con-
sist, no danger need be apprehended
should the soot ignite (an accident not
likely to happen), for such an accu-
mulation of soot as common chimneys
are liable to cannot take place within
these flues, there being no angles
within which it can lodge, the
draught of air being much stronger
through them, and the necessity for
cleansing them may be rendered less
frequent by vitrifying the inside of the
bricks to prevent adhesion ; never-
theless, the operation of cleansing may
with facility be performed without the
aid of climbing boys, all sharp angular
turns, and other impediments which
have hitherto opposed the use of ma-
chinery for this purpose being totally
avoided.
Whilst upon this subject, we have
great pleasure in calling the attention -
of our readers to a very effective machine for sweeping chimneys, invented by
Mr. Glass, which has been approved by the Society for sº the














3 a
3G6 CIIIMNEYS.
Necessity of Climbing Boys, and which seems applicable to almost every con-
struction of flues. The brush, Fig. 1, is made of a round stock a, commonly
alder, and pierced with small holes, into which bunches, formed of strips of the
best whalebone, are inserted and fastened by glue. These strips b are from 8
to 8% inches in length, which renders the brush, including the stock, about 20
inches in diameter; it therefore completely fills, and effectually cleanses, the
largest flues, which are never more than 14 inches square, and are seldom
more than 14 by 9 inches. At the end of the stock c is a very strong brass
ferrule, with a wormed socket, which receives the screw of the first joint. Fig. 2
is a representation of the ferrules of the real size; the three first portions did d,
2% feet in length, are made of good cane, the rest ee e of ground ash, and of the
same length, the number used of course depending upon the height of the
chimney ; these are made gradually stronger towards the bottom, and are
affixed to each other by means of the brass screws and sockets in Fig. 2, before
described. The superiority of this machine consists in extreme pliability,
lightness, and strength, which render it peculiarly applicable in high chimneys
having a diagonal portion at b, as shown in the annexed
Fig. 3. If Glass's machine be introduced through B, it
will proceed to the top of A with ease, whilst most
other machines generally stick at b. A common defect
in the construction of chimneys, although not so great
in houses of recent construction, is, that the aperture is
generally much larger than necessary for the passage
of the smoke, the consequence of which is, that the
fuel in the grate not being sufficient to rarefy the whole
portion of the air in the flue, the rising current of heated
air is met by a descending current of cold air, and the
smoke is borne back into the room. By Mr. Tredgold's
rule, before given, it appears, for a grate 18 inches wide,
a chimney 36 feet in height would require an aperture
of only 51 inches area, little more than 7 inches square,
whereas no chimneys are less than 14 inches by 9. It
is true that they could not be swept by climbing boys if
made of less dimensions; but if carried up in nearly a straight direction, without
abrupt bends, they might be easily cleaned by machinery, by which means a
barbarous and inhuman practice would be abolished, and the proper dimensions
being assigned to the chimney, the annoyance of smoke in the apartments
would be got rid of. The most effectual remedy for smoky chimneys is to
w
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contract the aperture, and lower the breast of the chimney; and when this has
been carried as far as is practicable, some further benefit may be derived by











































CHIMNEYS.
º
* * * *.*.*.*.*** Jº **
placing on the summit a revolving cap, turned hy a vane, so that the
for the smoke shall always be to leeward.
A machine of this description, invented by
Capt. Halliday, is represented in the engraving
on the preceding page. a and b are two square
plates of iron, or other metal, the upper one
being supported by four vertical pillars; c is
the aperture for the passage of the smoke from
the brick flue immediately beneath ; across
this aperture a bar is fixed horizontally, sup-
porting the upright spindle d, on the upper
end of which is fixed a double-tailed vane,
shown in plan at Fig. 2. Below the plate b
a square plate, forming a screen or guard, is
attached by braces to the spindle, and the
spindle being turned by the action of the
wind upon the vane, the screen is constantly
opposed directly to the wind.
The sketch below exhibits a smoke cowl
commonly used at Glasgow : — Fig. 1 is an
elevation, and Fig. 2 a plan or horizontal
section of the contrivance, which consists of
a quadrangular box of sheet iron, surmounted
by a pyramidical cap, , and placed, as exhi-
bited, over the top of the brick flue. There
are four doors to it, a b c d'; a is connected
by an intermediate rod f to the opposite door
c, and b, by the rod e to the door d, so that
when the wind closes the door opposed to it,
the opposite one is opened for the smoke to
escape uninfluenced by the wind.
The annexed engraving represents Mr. Fen-
ner's apparatus for curing smoky chimneys. It
consists of a spiral tube or flue to the upper
part of an ordinary chimney. These tubes
are made of thin copper, and furnished with
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368 CHURN.
a flange at the lowest end upon which it rests on the top of the brick-work
of the ordinary flue. The chimney is then continued upwards with a reduced
thickness of brick-work, by which means the capacity is sufficiently enlarged
for the reception of the spiral tube. The expanded part of the chimney is
closed in at top so as to form a hot-air chamber round the tube, which being
of thin metal, the heat is readily transmitted to the chamber.
CHLORINE. The name given by Sir Humphrey Davy to a gas which long
went, and even still commonly goes, by the name of oxymuriatic acid gas, as
being imagined to be a compound of oxygen and muriatic acid, but which he
showed to be a simple substance, which, when combined with hydrogen, formed
muriatic acid. Chlorine is commonly, in the small way, obtained by distilling
in a glass retort, at a gentle heat, 3 parts of common salt, 1 part of black oxide
of manganese, and 2 parts of sulphuric acid. The gas which comes over is of
a greenish yellow colour, and its odour and taste are disagreeable, strong, and
so characteristic, that it is impossible to mistake it for any other gas. Like
oxygen, it is a supporter of combustion, the products of which are termed
chlorides. It has two remarkable properties: 1st, Its affinity for hydrogen is
superior to that of any other substance, whence it is extremely useful in
destroying contagious miasmata; and 2dly, its destructive action upon vegetable
colours, with the aid of a little moisture. Scheele first remarked this property,
Berthollett applied it to the art of bleaching in France, and Mr. Watt intro-
duced its use into Great Britain. The alkaline metals, as well as copper,
tin, arsenic, zinc, antimony, in fine laminae or filings, spontaneously burn in
chlorine: metallic chlorides result. Phosphorus also takes fire at ordinary
temperatures, and is converted into a chloride. Sulphur may be melted in the
gas without taking fire. See BLEACHING.
CHOCOLATE. A kind of paste or cake pre-
pared from several ingredients, the chief and basis
of which is the cacao nut. The cacao, after being
roasted, is ground to a paste. The English manufac- [] .
turers are said to mix the flour of horse-beans, or
other farinaceous vegetable matter, to soften the ./
strong taste of the cacao; some vanilla and sugar are |
likewise added by them. The Spanish chocolate *
contains cloves, cinnamon, besides musk, ambergris,
&c., which are not agreeable to the English palate.
CHURN. A vessel in which butter is obtained
from milk or cream by agitation. A great variety | | USO º
of churns are in use ; a very common one consists
of a deep wooden tub, rather conical, resting on its
base, and having a wooden cover, through which |
passes the churn staff, to the bottom of which is
fixed a broad kind of foot, having numerous perfo-
rations to occasion a more universal agitation of the
milk in churning, the staff being worked briskly up
and down. From the mode in which the power
is applied in this kind of churn, the operation is
very laborious; another kind, therefore, called the
barrel churn, is now very generally adopted in our
dairies, which consists of a kind of rolling barrel
with an apparatus within it, calculated to quicken
the formation of the butter by promoting the agita-
tion of the milk. The annexed engraving repre-
sents an elegant little table churn, constructed of
glass by Messrs. Pellat and Green, which shows the
manner in which butter is formed in a very inte-
resting manner. a represents an axis placed verti-
cally in a glass cylinder, and furnished with four
leaves b b, placed at right angles to each other, (as seen in Fig. 2,) and notched
on the edges, and also perforated (as shown in Fig. 1). To the interior of
2,
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3.
3.
F
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CLARIFICATION. 360
the cylinder are fixed three leaves c c, at equal distances from each other, and
also notched on the edges so as to receive the projecting points of the leaves
attached to the axis, and nearly fit them, at the same time allowing the
movable leaves to pass freely, when the axis is turned round. The agitation
is produced by a rapid rotation of the axis with its leaves or fans, which is
effected by means of the bevilled wheel d and e, put in motion by the handle f.
CINCHONA is the bark of several species of cinchona, which grow in South
America; of this bark there are j varieties, the red, the yellow, and the
pale. The red is in large easily pulverized pieces, which furnish a reddish
brown powder, having a bitter astringent taste. The Ayellow Peruvian bark
was first brought to this country about the year 1790, and it resembles
pretty closely, in composition the red species. The pale cinchona is that
generally employed in medical practice as a tonic and febrifuge.
CINNABAR. A beautiful red pigment, composed of sulphur and mercury,
and hence in the chemical nomenclature called sulphuret of mercury.
CINNAMON. The inner bark of the laurus cinnamomum, a native of
Ceylon. It is a most grateful aromatic, of a very fragrant smell, and a mode-
rately pungent taste, and is an excellent restorative spice.
CIRCLE. A line continued till it ends where it began, having all its parts
equidistant from a common centre.
CIRCUMFERENCE. The periphery or line bounding or including any
thing.
CIRCUMFERENTOR. A mathematical instrument used by surveyors for
taking angles by the magnetic needle in cases where great accuracy is not
required, and where a permanent direction of the needle is of the most
material consequence in surveying. It consists of a compass box containing
a magnetic needle, supported on a pivot in the centre, and the circum-
ference of the box divided into 360 parts or degrees. The box is furnished
with two sights, placed on opposite ends of the meridian line, or 180° asunder;
it is also mounted on a pivot in the head of a tripod or stand. In taking
the angle between two objects with this instrument, the box is turned until one
object is seen through the sights, when the number of degrees to which the
south end of the needle points is noted; the box is then turned until the
second object be observed through the sights, and the degrees pointed to by
the needle again noted, and the difference between the two numbers is the
quantity of the angle.
CITRIC ACID. An acid obtained from the juice of lemons, although it is
also contained in various other fruits and vegetables. The usual method of
preparing it consists in saturating a quantity of the juice of lemons by chalk,
which thus forms citrate of lime, and afterwards decomposing the citrate by
diluted sulphuric acid, by which means sulphate of lime is formed, and the
citric acid is set free, and in this state it is used by the calico printers; but for
other ". it is crystallized by evaporation. There is an interesting paper
on this subject in Parkes's Chemical Essays.
CIVET. A perfume which bears the name of the animal from whence it is
taken, called a civet cat (found in China and the East and West Indies), but
bearing a greater resemblance to a fox or marten than a cat. Several of these
animals have been brought into Holland, and afford a considerable branch of
commerce, particularly at Amsterdam. The civet is collected near the anus of
this fierce carnivorous quadruped, and squeezed out in summer every other day,
in winter twice a week; the quantity procured at once is from two scruples to
a drachm or more. The juice thus collected is much purer and finer than that
which the animal sheds against shrubs or stones in its native climates. Good
civet is of a clear yellowish or brownish colour, not fluid nor hard, but about
the consistence of butter or honey, and uniform throughout; of a very strong
smell, quite offensive when undiluted, but agreeable when only a small portion
is mixed with other substances.
CLARIFICATION. The process of clearing or fining any fluid from
heterogeneous matter or feculence by chemical means, thus differing from
filtration, which is merely a mechanical operation. Clarification is performed
370 CLOGS.
either by heat, or by the addition of some substance which will unite with, and
either precipitate to the bottom, or carry to the surface, the matter which
renders the liquid turbid.
CLARINET. A wind instrument of the reed kind.
CLEPSYDRA, or WATER CLock. A contrivance of very great antiquity, to
measure the lapse of time, and indicate the hour by the
flowing of water into or out of a vessel properly graduated. In
the former case the vessel was divided by lines into a number
of equal parts, which would be filled with water in equal por-
tions of time provided the source from whence the water was
obtained was so abundant as to render the hydrostatic pressure
upon the discharging aperture nearly equal. Such clocks, how-
ever, could be employed in particular situations only, the latter
plan was therefore most commonly adopted, viz. to measure
by the discharge of water from the vessel; but as in this plan
the velocity of the water would not be uniform, but would
decrease with the decrease of the water in the vessel, equal
quantities of water would not be discharged in equal times,
and some contrivance became necessary to compensate this
inequality. The most common was to employ a vessel of larger
diameter at the upper than at the lower end, and divide the t
altitude into a number of equal parts, or else to use a vessel |
of equal diameter throughout, and divide the height into a || ||
number of unequal parts, gradually diminishing from the top;
but each of these methods was difficult to execute accurately.
The cut in the margin represents a contrivance of Mr. Par- !
tington's, by which these difficulties are avoided, and equal
quantities of water are discharged in equal spaces of time. a
is a cylindrical tube to hold the water, and b a cork float on its º
surface, through which is passed the shortest leg of a narrow || 4 |
syphon c, which is suspended by a silken cord over a wheel d, . . .
and to the other end of the cord is attached a weight, which
nearly counterbalances the syphon; near to the extremity of:
the syphon is fixed an index f. that points out upon a graduated:
scale the hour, according to the degree of depression within
the tube. It is obvious that as the float by which the syphon
is supported is always immersed to the same depth in the
water, the outer leg of the syphon will always remain in the
same relative position to the surface of the water in the tube,
and thus the hydrostatic pressure will be always the same, the
flow or discharge will be uniform, or equal portions will be
discharged in equal times, and the tube being cylindrical, or
of the same dimension throughout its length, the scale cor-
responding to its altitude will be divided into equal parts;
thus the instrument forms a very accurate measurer of time.
The water falls into a receiverg, which forms the base of the
instrument, and may be made to run back into the tube by
opening a passage between them, and inclining the instrument.
CLOCK. An instrument for measuring and indicating time.
See HoRology.
CLOG. In the manege, a log of wood fastened to the
fetlocks of a horse, to break him in to a peculiar kind of pace
or step.
CLog. A sort of shoe with a thick sole of wood or leather, worn over the
ordinary boots and shoes in dirty weather. Although clogs are more easy to
walk in than pattens, as affording a firmer footing, they are not so cleanly, as they
splash and throw up a deal of dirt. The figures on the opposite page represent a
combination of the clog and the patten, affording the security and firmness of the
tread of the former, and the cleanliness of the latter. Fig. I shows the patten
clog in perspective, and Fig. 2 the same turned upside down. a is the patten
;
|
|
i
i.






CLOGS. 371
iron, of the peculiar form represented, which is found not to splash in the least;
it is rivetied to the bottoiſi of the clog, as a support to the heel, and is upon a
level with the projecting or thickest parts b of the sole that supports the fore
part of the foot. The clog is hollowed out at c to render it lighter, and to cause
it to take up less dirt. One objection to clogs, as usually constructed, is the
º º
2: sº
|
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§ *T.
§
N
Nº.
fatigue they occasion in walking, from their want of flexibility. This defect has
of late years been remedied by forming the sole of two or more pieces, con-
nected by hinges; and a further improvement has been introduced by Mr.Schaller,
who has obtained a patent for what he terms “expanding clogs or pattens,”
which may be lengthened or contracted at pleasure, so as to fit the foot of the
wearer with the greatest exactness. These expanding clogs, are represented in
the engravings on page 372. Fig. 1 represents a man's clog in perspective, with
the contrivance for expanding or contracting the same. Under the brass ferule
at a is a sliding rack and spring, or other contrivance, by which the clog can be
lengthened or shortened at pleasure; at b is another rack and spring, which
allows the raised sides of the heel-piece to be expanded or contracted breadth-
wise. To the strap c is likewise attached an improved spring slide, by which
that also may be lengthened or shortened: these several contrivances are
exhibited in detail in Figs. 2, 3, 4, 5, 6. Fig. 3 represents a plan of the upper
side of the sole of the clogs, without the brass ferule or sheath a, and with
another flat plate, which encloses the work underneath, removed; the rack d
and the spring e are thus brought into view, the former being screwed to the
waist of the sole, and the latter to the heel piece, in cavities or mortises made
to receive them; they are likewise so fixed that the spring always keeps in
contact with the rack, as shown by the edge view of them in Fig. 4, where it
is seen that there is a stout pin f which goes through a slot mortise in the rack:
this pin slides backwards and forwards in the slot mortise. By this arrange-
ment it will be seen that the clog may be contracted by simply thrusting the
toe part towards the heel, as the spring catch, which is fastened to the former,
slides over the notches in the rack; but to pull the toe from the heel, in order
to lengthen the clog, it becomes necessary to press upon the brass pin f, which
in this clog protrudes a little way either on the upper or the under side. Fig.2




















372 CLOGS.
represents a plan of the upper sole of the superadded heel-piece, which consists
of a metal plate g. The sides h h are here shown as expanded for a large foot;
to contract it to suit a smaller foot it is only necessary to press the sides h fi
together, when a spring catch (nearly similar to that already described in the
other part of the clog) slides over the notches of a rack, and fixes itself wherever
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it is left. On the contrary, when it is wished to increase the capacity of the
heel, the guide pin i which slides in the slot mortise k is to be pressed upon by
the thumb nail, which thrusts the spring catch out of contact with the rack,
and the sides h h spring out again in the position shown in the figure, owing to
their having a metallic lining (of thin plate iron), which possesses, sufficient
elasticity for that purpose; the four screw holes, shown in the heel-plate g, are
for the purpose of fastening it down to the wood or leather heel-piece of the
clog. The slide for lengthening or shortening the tie of the clog across the
instep of the wearer is shown on an enlarged scale at Figs. 5 and 6, the same

COAL MINE. 373
letters in each referring to the same parts. It consists of two plates l l laid
flat-wise in contact with each other, with four long apertures or slots, in each of
which slides a brass pin; two of these pins are rivetted to each plate, and confine
the opposite plate in contact by their heads projecting over it. To give an
increased friction to the sliding plates, and to stop their action, a spring n is fixed
to one of the plates, with a brass catch pin o at the other end, so that when the
slide is shut up, as shown in Fig. 1, the pin o enters the hole p, where it is
retained, until pressed out again in order to lengthen the tie as may be required.
Fig. 7 represents a clog more especially adapted to ladies' wear, in which another
mode of lengthening or shortening the clog is adopted. In this instance a thin
iron bar or plate is perforated with holes and rivetted to the fore part of the
sole, and kept steady by two pins on either side; the other end of the perforated
late enters the heel of the clog, and is so formed at the extremity as to prevent
it being entirely drawn out. Now the brass sheath a has a hole at q, and
another directly opposite to it at the bottom; the pin r being then passed through
both holes in the brass sheath, and through one of the holes in the intervening
perforated plate, fixes the clog firmly in the place required.
CLOTH. A general name for any fabric woven from any fibrous materials
(except silk), such as flax, cotton, &c., but it is mostly used to signify cloth
made from wool. See WEAviNG and WoolleN MANUFACTURE.
CLOUTS. Thin plates of iron, which are nailed to the wooden axletrees of
carriages.
CLOVES. The produce of the caryophillus aromaticus of Linnaeus, which
grows in the Molucca Islands, particularly in Amboyna, where it is principally
cultivated. The clove tree resembles in its bark the olive, and is about the
height of the laurel, which it also resembles in its leaves. No verdure is ever
seen under it. It has a great number of branches, at the extremities of which
are produced vast quantities of flowers, that are first white, then green, and at
last red and hard. When they arrive at this degree of maturity, they are,
properly speaking, cloves. The season for gathering is from October to February,
when the boughs of the trees are shaken, or the cloves beaten down by reeds,
large cloths being spread to receive them. These are afterwards either dried
in the sun, or in the smoke of the bamboo cane.
CLUTCH. A mode of connecting shafts with each other or with wheels, so
as to be disengaged at pleasure; numerous examples of which have been given
in the preceding part of this work. See also MILL work.
COAL. A carbonaceous substance lying in strata at various depths beneath
the surface of the earth, and extensively used for fuel. The varieties of coal
are scientifically described by Dr. Jamieson in his geological work, and classed
in several species and subspecies; but, in a practical point of view, they may be
divided into three classes, according to their degree of inflammability. The
least inflammable kind is the anthracite, or stone coal, of which class is the Welsh
and Kilkenny coal. It requires a considerable degree of heat to ignite it, but
when once kindled it remains in distinct pieces in the fire without caking, pro-
ducing neither smoke nor flame, making no cinder, but leaving a stony slag
behind. It is chiefly used in malt kilns, dye-houses, &c. Open burning coal
kindles quickly, makes a hot pleasant fire, but is soon consumed, and produces
smoke and flame in abundance; it lies open in the fire, and does not cake
together to form cinders, its surface being burnt to ashes before it is thoroughly
calcined in the middle. Of this kind is Cannel coal, jet, and most of the
Staffordshire and Scotch coals. Close burning coal kindles quickly, makes a very
hot fire, melts and runs together like bitumen; it makes a more durable fire
than any other kind of coal, and burns finally to ashes of a brownish colour.
Of this kind are the Newcastle coals, and those of the surrounding districts.
The various kinds of coal are often found mixed with each.other, and at times
some of the finer sorts run like veins between the coarser sorts. -:
COAL MINE. Strata of coal are to be met with in various parts of the
globe, as France, Germany, Sweden, America, Australia, and we believe likewise
in India; but in no country in such profusion, or of so good a quality, as in
Great Britain; and to this circumstance we may mainly attribute our commercial
3 B
374 COAL MINE.
greatness, and our superiority in almost every branch of manufacture. In coal
mining, and the carrying trade, a vast portion of our population is employed,
besides many hundreds of thousands of tons of shipping constantly engaged in
transporting this valuable mineral not only to all parts of our own coasts, and
up our rivers, but to almost every part of the Netherlands, France, Spain,
Portugal, the West Indies, and America. The principal seat of the coal trade
is in the northern and eastern parts of England, and the most important coal
works are those of Newcastle and Whitehaven; at the latter place some of the
mines extend more than a mile under the sea, and at a depth considerably
greater below its surface than has been reached in any part of the world, the
deep mines of South America being situated upon lofty mountains considerably
elevated above the surface of the earth.
We shall now proceed to give a brief description of the method of working
a coal mine. To ascertain whether coal is concealed beneath the surface at any
place, recourse is had to boring, by a process and implements similar to what
we have already described in our account of the method of boring for water;
and an account is carefully kept of the different strata cut through, and of the
depths to which they extend before arriving at the principal bed of coal; and
the thickness of the coal strata in different situations, as well as the dip or
inclination of the strata, (for they seldom lie horizontal,) are ascertained by the
same means. The working is usually commenced upon the dip, as it is termed,
or where the depression of the strata of coal is greatest. The first consideration is
the means of draining off the water from the feeders and springs with which the
coal is usually intersected. If the situation and other circumstances will admit of
it, an adit is driven through the side of the hill to the lowest part of the mine,
and the water runs off by it to a lower level; but if this cannot be effected, the
water is raised by pumps worked by horses, water, or steam, according to
circumstances. For this purpose a pit or shaft, termed the “engine shaft,” is
sunk (generally upon the dip of the coal), in order to allow the water to drain
from the workings and to keep them dry. . In this shaft the pumps are placed,
divided into sets at the various depths of the mine, the lowest set delivering its
water into a cistern, from which it is raised by the next set of pumps above it, and
so on to the surface, the lift for each set seldom exceeding 25 to 30 fathoms.
When the required depth is attained, a portion of coal is worked dipward of the
engine-shaft, forming a cistern for the waters to collect in. A level is then cut,
from the bottom of the engine-shaft, called the gateway, or winning headway,
which, as the works proceed, is carried the whole length of the mine, and is
from 8 to 10 feet high, and 9 feet wide. When the gateway has proceeded
to the required distance from the engine shaft, another shaft is sunk to meet
it called the coal shaft, or pit, by which the coals are conveyed to the
surface in baskets by a gin. From the gateway, or winning headway, the coal
is worked from passages cut at right angles, called “rooms,” which are about
12 feet wide; and other passages again are cut at right angles to the rooms,
which open from one room into the next, and are called “thoroughs,” or thirt-
ings, the coal remaining thus forming pillars for the support of the roof. When
the coal is of a firm texture, from two-thirds to three-fourths may be got out
at the first working; but in other cases little more than a half. Two large
blocks or pillars, 15 or 20 yards long by 10 or 15 yards wide, are left to
protect engine and coal-pit, in case of the falling in of the mine. The coals
are brought to the pit or shaft in small cars, drawn by horses when the workings
are wide and moderately level; but if too steep or narrow, are drawn by men
in baskets upon trucks; or if too steep for this, are carried in baskets upon the
backs of women. . A general idea of the operations and arrangements of a coal-
mine may be gathered from the accompanying section of Bradley Coal Mine,
near Bilston, in Staffordshire. A, the whimsey, or steam-engine for raising the
coal from the bottom of the shaft; B, the banksman who lands the same; C,
one of the shafts of the mine; D, a passage from one shaft to another; E, the
gateway, or head-winning way; F, the bolt hole, made to cause a free circula-
tion of air through the mine; (should any part take fire, the bolt hole is built up;)
G, pillars left in working the ten-yard coal, to support the superjacent strata;
COAL MINE. 375
H, an excavation called a sta!, or room, by the colliers, who, after the gateway
is cut, begin thus to work the coal, or hole-under; I, the ribs through which
the air-way is cut; J, lights; K, a man who hangs on the skips, and rakes the
gateway; LM N, miners heading, holing, and shovelling out the slack or
small coal; O, slack carrier; P, miner working on a scaffold; Q, the spern,
a small piece of coal left as a support to many tons above, which fall when this
is taken away; R, a collier on a scaffold, taking out the spern as far as he can
reach with a pick; S, a collier standing upon a heap of slack, called the gob,
with a prong used for that work, which cannot be safely done with a pick; T,
} º - A - sº)) 'A),
Ž2~22 R- -i.
Wººl
ſº
M
iniº
RN I
É||
a collier breaking or turning out coal; U, a collier loading a skip ; V, a
collier breaking the large coal with a wedge; W, a driver with an empty skip,
X, a driver with a loaded skip; Y, a skip being drawn up the shaft by the
engine; Z, a pillar, called the man of war, left to support the upper
strata until the lower are worked; it is then taken away, and the upper
coal falls down. The different strata that are cut through to arrive at the
principal bed of the coal are exhibited on the left of the shaft, by variously
shaded portions of the solid earth, extending in the Bradley mine to the depth
of about 111 feet,-the depth to the bottom of the shaft is 139 feet 4 inches.
In the extensive collieries in the vicinity of Newcastle a complicated and




376 COAL MINE.
expensive system of ventilation has been adopted, in order to guard against the
disastrous consequences which result from an accumulation of fire-damp or
hydrogen gas; but from the calamitous explosions, which are of such frequent
occurrence, it is but too clear that the system is deplorably inefficient, and calls
loudly for improvement. The accompanying sketch represents, on a small
scale, the plan which is pursued to counteract the effects of that fatal evil, and
to spread throughout the workings a sufficient quantity of fresh air. The dark
parts in the plan represent the pillars of coal left to support the roof, and the
light parts the workings. There are generally two descents or more to the
mine, as we have already stated, which are distinguished by the terms of the
downcast and upcast shaft. A is the downcast shaft by which the air descends;
the current of the air is represented by the waved line, which is carried through
the main passages only, the subways which diverge from them being stopped
by the brattices; and its motion is accelerated by the heat of a large fur-
nace, situated at the bottom of the upcast shaft B; and thus the air, after
traversing the whole of the workings, ascends the shaft B. An exhausting
pump placed near the upper end of the upcast shaft B is sometimes substituted
for the dangerous expedient of the furnace at the bottom of the shaft. But
when particular parts of the mine are subject to rapid accumulations of fire-
damp, recourse is had to the firing process, which is usually performed by means
of an apparatus, consisting of a long pole, or a series of poles, fitting one into
another like a fishing-rod, so as to be elevated to the break, or pot-hole, where
the fire-damp has accumulated; at the upper end of this pole is a small sheeve or
wheel, over which a copper wire passes, of sufficient length to reach to the horse
stable from any part of the mine; this done, the pole is firmly fixed in the
place where the gas lodges. A candle, fixed to a piece of lead or other substance
to keep it upright when suspended, is carried by the fireman as far towards the
explosive region as safety will admit, when it is set upon the floor, and fastened
to one end of the copper wire, after which the firemen retire to the stable,
which is made strong and well secured, in order to barricade them: the other
end of the wire is brought through a crevice in the door, and by this means the
light is drawn up to its destination; and the gas which has accumulated,
coming in contact with the flame, ignites and explodes. In some instances the
firemen remain pent up a considerable time in the greatest suspense, owing to
some accidental circumstance having put the candle out before it reaches the
pot-hole, when they are fearful of venturing, from the uncertainty of what may
be the event. In many instances it has been found necessary to explode these
lodgments three times a day, at each time clearing the mines of all the work-
men except the firemen; the necessity of which has been occasioned by the
miners cutting down strata or measures of coal, so as to render the roof higher

COAL MINE. 377
than the general run, of six or eight feet seams, and by these means making the
extra elevation too great to be effected by the diluting current. In fact, where
the roof of a coal mine (where the seam is thirty-six feet thick,) is cut down, no
means but the firing process could suspend for a single day the destructive
effects produced by an explosion of the whole mine. To obviate the dangers
and difficulties of the firing process, Mr. James Ryan, of Netherton colliery,
near Durham, who had been for many years engaged in working mines, invented,
in lieu of it, a simple, effectual, and economical system of ventilation, by which
the fire-damp, or inflammable gas, was carried off upwards from the mine;
whilst by another arrangement he caused the carbonic acid gas (or choke-damp)
to pass off into the water level. In attempting to get his plans of ventilation
tried at various mines, he met with the most stubborn opposition; and although in
every instance in which he was allowed to introduce his system, he was eminently
successful, yet, from the misrepresentations of ignorance and jealousy, his
system of ventilation has been adopted in very few mines, and the firing pro-
cess is still very generally resorted to. Mr. Wood, of Summer Hill Grove, Nor-
thumberland, has however invented an apparatus by which the firing may be
effected without any personal danger. The annexed diagram represents the interior
º
§
:
of a coal mine in perspective, with Mr. Wood's apparatus employed in igniting
the gas. It consists of a common Dutch striking clock, in which the descent of a
Weight at a previously determined hour raises a lever having a counterbalance
Weight; this lever acting upon another lever, causes a match, charged with

373 COAL MINE. …
oxymuriate of potash, to be dipped into a bottle containing sulphuric acid; the
counterbalance weight on the first lever immediately afterwards draws the
match out of the bottle, when the contact of the air causes the match to ignite,
and to set fire to a train of combustible matter connected with it, consisting of
cotton or tow saturated with spirits of turpentine. a represents the weight of
the clock, which is set to go off at the time denoted; a projecting piece at the
bottom of the weight presses in its descent upon one extremity of a lever, which
turns upon a fulcrum at b : the other end of this lever is provided with a roller
c, which raises the loaded end d of another lever, supported upon a standard at
e; at f is a rod attached by a joint to the other extremity of the second lever, and
at the lower end it is jointed to a small block, to which is fixed the match. To
the match are attached some loosely twisted filaments of cotton, which are
carried upward, and wound round an iron rod as loosely as possible, so as to
form a large bunch of easily ignitable matter, to further which the whole is
saturated with spirits of turpentine: the iron rod containing the bunch of
cotton slides up and down in a fixed standard i, as represented; and from this
point a train is made to other parts of the mine, where the inflammable gas
may have collected in a detached volume, by means of strips of brown paper
dipped in oil of turpentine, which are strung together and suspended in festoons
on standards fixed in the ground. The clock being set to go off when all the
workmen are absent from the mine or at rest, the weight operates upon the
lever at the precise period determined upon, ignites the match and the train,
and thus destroys all the inflammable gas.
The following is a simple and useful contrivance for the prevention of
accidents in raising men or minerals out of mines, by the ropes “running wild,”
as it is termed, and for which the inventor, Mr. E. Speers, was presented with
the silver Vulcan medal by the Society of Arts. A bar is fixed on the end of
an axis. Two hooks, as A,
swing freely on the ends of
this bar; C is a short bar ...--------------.
or stop, projecting from a'
the frame of the machine,
for the hook to catch hold
of. When the bar re-
volves at a moderate rate,
the hooks constantly hang
down by their own weight,
and keep clear of the stop
C; but when it revolves with
a dangerous rapidity, the
centrifugal force causes the
hooks to diverge from their
pendant position, and one of
them catches hold of the
check-bar C, (as shown by
dotted lines,) which stops
the machine instantly.
A correspondent in the Register of Arts proposes the following modification
of this contrivance, by which the shock occasioned by the sudden stoppage of
the machinery is avoided, and the further advantage gained, that when the
velocity of the machinery is so far reduced as to avoid danger, the machinery will
not stop, but will recommence motion of itself. In the engraving in the next page,
a is a section of Mr. Speers' check-hooks; the bar to which the hooks are sus-
pended turns with the axle b c ; e is a conical pulley, with grooves cut in
a spiral direction, as represented in the section; this pulley turns on the axle,
and not with it, like the bar a out of this pulley projects the check-pin f.
G is a screw fixed to the frame h, which fits into the pulley e, so as to enter
it as soon as the pulley is made to revolve in the same direction as the bar a.
i is a cord fixed to the pulley e, so as to be wound round all the grooves when the
pulley is turned; to the end of it is fixed a weight, the size of which must

COCKS. 379
be regulated according to the velocity
with which the machine is required to
work. From inspection of the plan it
will be seen that when the check-hooks, # h.
by the too rapid revolution of the check- } É E
bar a, have diverged so far from their H in *E
pendant position as to lay hold of the & = : F Cº
check-pin f, the pulley e will be drawn H t ſº
--
-
|
round in the same direction as the bar
a, and will wind the weight suspended
by the cord i until the cord reaches the
uppermost groove, as at l, when the
velocity of the machinery will be greatly
moderated, at which time the pulley e
will have advanced so far along the
screw G as to draw the check-pin out of
the check-hooks, when the machinery
will proceed in a regular way, and the
cord i, by the descent of the weight
attached to it, will reverse the motion
of the pulley, and return it to its original
position, as shown at i, where it will be
always ready to regulate the machinery
when the check-hooks, by their centrifugal force, come in contact with the
check-pin f.
COBAL.T. A metal of a whitish grey colour, similar to tin, but with little
brilliance. It is brittle and easy to pulverize, but difficult to fuse, requiring
a temperature equal to that which is necessary to melt cast iron. Like iron it is
attracted by the magnet In its metallic state it is of little use, but its oxide is
employed to impart a blue colour to fusible and vitreous substances. See
ZAFFRE and SMALTs.
COCOA-NUT is a native of most of the tropical countries; the tree is from
40 to 60 feet high, the leaves from 10 to 15 feet long, and 3 feet broad. The
fruit is about the size of a man's head; it contains a white kernel, the hollow
of which is filled with a milky juice. The uses of the cocoa-nut tree are numerous
and important. Its trunk is made into boats and water-gutters; and in house-
building, the leaves serve for thatch, and are wrought into mats and baskets;
likewise as a substitute for paper in writing upon. The fibrous husk of the
shell, after being soaked in water, is beaten into oakum, spun into a variety of
yarns, woven into sail-cloth, and twisted into ropes and cables even for the
largest ships. The hard shell is polished and formed into cups, powder-
boxes, &c.
COG. The tooth of a wheel, by which it acts on another.
CLARION. A kind of trumpet, whose tube is narrower, and its tone acuter
and shriller, than that of the common trumpet.
COCHINEAL. An insect which feeds on the Oactus opuntia, or prickly pear
of Mexico and other parts of South America. In the dried state in which it is
brought to Europe it resembles grains about one-eighth of an inch long, with
one side round and transversely wrinkled, and the other rather flat. The colour
is of a purplish grey; the grey is owing to a powder which covers it naturally;
the purple tinge proceeds #. the colour extracted by the water in which it
has been killed. The rich crimson colouring matter which it yields does not
appear to be injured by long keeping in a dry place, some cochineal of 130
years' old having been found to produce the same effects as new. The colour-
ing matter may be extracted either by water or alcohol. Alum was formerly
the only substance used to fix the dye of cochineal. About the year 1650,
Drebdel, a German chemist, discovered the effect of tin in heightening the colour.
The solution of tin in different acids will produce crimson, purple, violet, and
scarlet of various kinds. See CARMINE.
COCK. An instrument for permitting or arresting the flow of a liquid at
º
;
ºt


380 COCKS.
pleasure. They generally consist of a short tube communicating with the cask
containing the liquid, and having a plug ground into it near the middle, and
standing at right angles to it. This plug has a hole through it, which being
brought to coincide with the bore of the pipe, the plug offers no obstruction to
the liquid, but by turning the plug one quarter round, the solid part of the plug
stands across the bore of the pipe, and stops the passage of the liquid.
Numerous peculiarities are to be found in the construction of cocks, to adapt
them to particular uses; some of these we shall proceed to notice.
The annexed figure represents in section, an improved lock-cock for liquor-
casks, invented by Mr. W. Russel. Numerous patents have been taken out for
; §
t
$:_- ^s N. "---J
āş, -
zºrama.…* sº *º
~ * —º-º-º: . ... º.º.º.
E. G. ...-:...i. tº 2. º: Tº
ECEO =CEO
ºn ºr
º:
23
Iſaiaa.…aŻ - %
łock-cocks; but few of these inventions, we think, are equal to Mr. Russel's for
simplicity and security. The engraving represents the cock shut and locked. A
square hole being cut through the barrel and into the plug a, a movable steady
pin or bolt b, with a shoulder to limit its action, is fitted into it, passing through
the barrel into the plug; the opposite end terminates in a screw, over which is
a spiral spring resting on the shoulder; a turned brass socket c, having also
a shoulder about midway to press upon the spiral spring, is then put over all,
and secured to the barrel either by solder or screws; if by the latter only, the
notches in the heads must be filed away for obvious reasons. To open the cock,
or rather to withdraw the bolt, the screwed socket key must be introduced,
when about two turns will sufficiently compress the spring and withdraw the
bolt, and the cock may then be opened and shut at discretion, while the screw-
* key remains in the position described. When the key is withdrawn, the action
of the spring upon the plug forces the bolt into the aperture of the plug upon
sent another contrivance of Mr.
Russel's, which he has named a #
“hydro-pneumatic liquor-cock, and
air-vent attached,”the object of which
is to admit the air to press upon the -
surface of the liquor, so as to cause
*
shutting the cock.
The accompanying figures repre- £ior. 1. of 3)
it to flow upon opening the cock, |
but to shut off all communication
between the atmosphere and the -
interior of the vessel when the : -
cock is closed, by which the #||
strength of the liquor is preserved, #-
and it is prevented from speedily
turning sour. Fig. 1 is a view of
the cock with the air tube applied
externally. The plug, in addition
to the aperture for the passage of ºn
Tºffl
W
&
&
62
|















COCKS 381
the liquor, has a smaller one placed
di)0 Ve IU IOR Ulle trailS1111SS1011 Q1 L Ilê
air; upon turning the cock, to draw
off, the air enters the smaller pas-
sage, and passing along the bent
tube b enters the vat above the
surface of the liquor through the
metal plug or ferrule d. Fig. 2 is a
section of a barrel showing another
modification of the apparatus, by
which the air-tube is placed inter-
nally; this method is considered
preferable in brewers' or distillers’
large vessels, and in situations where
the tube, if applied externally, would
be liable to injury. Letters a b c d
and e apply to the same parts as in
Fig. 1; but the aperture for, the
admission of air in this cock is
situated at the side (at e), in order
to show the application of the inven-
tion to one of Mr. Russel's lock-
cocks, already described.
The following cut represents a cock of simple construction, in which there is
no plug requiring grinding into its seat, and which may be entirely formed of
castiºn, which is at once cheaper and not pernicious like brass, a is the
%
% Ži) |7
K. -
d(
barrel; b a small rod having a screw cut on the end g, which works in a
corresponding screw cut in the nose of the cock; the other end of the rod
passes through a guide-piece e (perforated with numerous holes, to allow an
easy passage to the liquor), and through a leather washer, at the back of which
is an iron washer, against which the rod is rivetted; and according to the
direction in which the screw is turned, the leather washer is either pressed
against the end of the cock, thereby closing the aperture, or it recedes from it,
and opens the passage. ff is a section of the cask into which the cock is screwed.
Another coºk, in some respects resembling the preceding, but requiring







3 c
382 COFFEE.
greater accuracy of workmanship, is shown in the following figure. a is the
barrel, bored out cylindrical, and the interior end faced or filed square; b the
nozzle; c a conical plug formed upon one end of a screw; d a handle upon the
*ther end of the screw, by turning which the plug may be made to close the
N sº
Sºğ
%
º
º
i’s
sº º à%
º
{
•
tº tº
º
W
é
sº
#.
º
º
º passage a, but when drawn back to the fullest extent, it leaves a
clear passage for the liquor. A great objection to metallic cocks is their liability
to corrosion in liquors containing any portion of acid, by which means the plu
becomes loose in its seat, and in many instances a poisonous solution of the metal
is formed in the liquor. These evils are avoided in Ridgway's porcelain cocks,
which are not liable to corrosion in the strongest acids, at the same time they are
very firm and substantial, being formed of the strongest porcelain or stone ware.
The forms of the cock are somewhat new, as well as the interior construction.
The annexed diagram gives a section (excepting the upper or handle part of the
plug,) of the form most approved by the patentees, a is the long tube, with a
screw thread cut upon its external surface for the purpose of being screwed into
the barrel; b the plug accurately ground, and fitted into its place; in the plug
a vertical perforation is made by
boring, equal to the diameter of that
in the long tube, and another hole
at right angles to the former to com-
municate with the vertical perfo-
ration and with the long tube, when
the plug is turned in the direction
shown, for drawing off the liquor.
To secure the plug in its place, and
to produce a uniform action, it has
a groove made three-quarters round
it, for receiving the end of the bolt
c which is fastened by the screw d.
See WALves.
COFFEE is the seed contained in a berry, the produce of a moderate sized
tree called the Coffea Arabicum, and which has also been named Jasminum Ara-
bicum. This tree grows erect, with a single stem, to the height of from º
to twelve feet, and has long, undivided, slender branches, bending downwards,
these are furnished with evergreen leaves, not unlike those of the bay tree.
The blossoms are white, sitting on short footstalks, and resembling a cherry,
and having a pale, insipid, and somewhat glutinous pulp, inclosing two hard
oval seeds, each about the size of an ordinary pea. One side of the seed is
convex, while the other is flat, and has a little straight furrow inscribed through






C() FFEE. 383
its longest dimensions; while growing, the flat sides of the seed are towards
each other. These seeds are immediately covered by a cartilaginous mem-
brane, which has received the name of the parchment. The trees begin bearing
when they are two years old; in their third year they are in full bearing.
The aspect of a coffee plantation during the period of flowering, which does not
last longer than one or two days, is very interesting. In one night the blos-
soms expand themselves so profusely as to present the same appearance which
has sometimes been witnessed in England when a casual snow-storm at the close
of autumn has loaded the trees while still furnished with their full complement of
foliage. The seeds are known to be ripe when the berries assume a dark red
colour, and if then not gathered will drop from the trees. The planters in
Arabia do not pluck the fruit, but place cloths for its reception beneath the
trees, which they shake, and the ripened berries drop readily. These are after-
wards spread upon mats, and exposed to the sun's rays until perfectly dry, when
the husk is broken with large heavy rollers, made either of wood or stone. The
coffee thus cleared of its husk is again dried thoroughly in the sun, that it may
not be liable to heat when packed for shipment. The method employed in the
West Indies differs from this. Negroes are set to gather such of the berries as are
sufficiently ripe, and for this purpose are provided each with a canvass bag, having
an iron ring or hoop at its mouth to keep it always distended, and this bag is
slung round the neck so as to leave both hands at liberty. As often as this bag
is filled, the contents are transferred to a large basket placed conveniently for
the purpose. It is the usual calculation, that each bushel of ripe berries will
yield ten pounds' weight merchantable coffee. In curing coffee it is sometimes
usual to expose the berries to the sun's rays, in layers five or six inches deep,
on a platform. By this means the pulp ferments in a few days; and having
thus thrown off a strong acidulous moisture, dries gradually during about three
weeks: the husks are afterwards separated from the seeds in a mill. Other
planters remove the pulp from the seeds as soon as the berries are gathered.
The pulping-mill used for this purpose consists of a horizontal fluted roller,
turned by a crank, and acting against a movable breast-board, so placed as to
prevent the passage of whole berries between itself and the roller. The pulp
is then separated from the seeds by washing them, and the latter are spread
out in the sun to dry. It is then necessary to remove the membranous
skin or parchment, which is effected by means of heavy rollers running in a
trough wherein the seeds are put. This mill is worked by cattle. The seeds
are afterwards winnowed to separate the chaff; and, if any among them appear
to have escaped the action of the roller, they are again passed through the
mill. The roasting of coffee for use is a process that requires some nicety; if
burned, much of the fine aromatic flavour will be destroyed, and a disagreeable
bitter taste substituted. The roasting is now usually performed in a cylindrical
vessel, which is continually turned upon its axis over the fire-place, in order to
prevent the too great heating of any one part, and to accomplish the continual
shifting of the contents. Coffee should never be kept for any length of time
after it has been roasted, and should never be ground until it is required for
infusion, or some portion of its fine flavour will be dissipated. Count Rumford,
who paid great attention to the management and preparation of coffee, used to
preserve the aromatic fragrance of that which had been ground, by placing
it into a cylindrical metallic box, which was covered by an accurately fitting
piston in the inside, being well closed by a nicely adjusted cover on the
outside. An improved apparatus for roasting coffee was H. by Mr.
Evans in 1824, the operation of which, it is said, confers a flavour similar to
that from Mocha to West India coffee; and, owing to the retention of the
essential oil, a greater weight of roasted coffee is obtained from a given weight
of the raw material. The art, according to Mr. Evans's practice, seems to con-
sist in the abstraction of the aqueous and acidulous matter, without volatilizing
the essential oil, upon which mainly depend the flavour and agreeable qualities
of coffee. The apparatus consists of an elliptical iron retort, set in brick-work,
over a furnace; the retort is made to revolve upon hollow axes, one of them
ecrying as an exit passage for the vapour, which is delivered therefrom into a

384 COFFEF,
convoluted pipe, immersed in cold water, and is thereby condensed; the other
hollow axis is for the convenience of introducing the “examiner,” which is a
perforated tube, used to draw out a sample of coffee under operation, while
it serves also as a safety valve in case of the vapour accumulating in too great
force. A series of the retorts are placed over their respective furnaces, and
they are caused to revolve by geering connected to their axes, to which motion
is given by a steam engine, or any other convenient power. When the roasting
has been found complete, the retorts are lifted out of their apertures over the für-
nace, and turned over upon one of their axes, which is provided with an ingenious
swivel bearing for that purpose; the coffee is then discharged, and the operation
renewed upon a fresh quantity. In the ordinary method of roasting coffee an
acetic acid is generated, which is diffused in the liquor if the infusion remains
long. To obviate this inconvenience, an apparatus was contrived called a
biggin, in which the coffee is put into a bag suspended to the rim of the vessel,
and boiling water having been poured through, it is separated and removed
from the water, which remains pretty free from acid, and combined with much
aromatic fragrance. In coffee roasted by Evans's distillatory process, before
mentioned, the acetic acid is mainly got rid of, and therefore the same pre-
cautions that are used in the biggin are not necessary, and a richer infusion
may be made by allowing the coffee to soak longer in the water; but as the fragrant
principle is of a very volatile nature, Mr. Evans contrived the following apparatus,
which is found to answer the objects in-
tended extremely well, and will serve for
the foundation of a machine of a more ele-
gant exterior. The body a of the vessel is
of a cylindrical form ; it has a cover b at
top, and at c a bottom, under which is a
stand or furnace d containing a lamp e : at
f is a floating piston with a hook under-
neath for suspending the ground coffee
in a bagg. The floating piston is made
of two thin metal plates soldered together,
with a hollow space between them capable
of holding a sufficient quantity of air to
render itself and the bag of coffee buoy-
ant. The piston is accurately fitted to
the cylinder, but so as to allow it to rise
and fall freely with the surface of the
liquid in which it floats, and thus pre-
serve the infusion from the contact of
air, and there is only an extremely fine
circular line of liquor at the edges ex-
posed; the heat and the aroma of the
infusion is thus preserved until the last w
cup is drawn off. When coffee is ground to a fine powder, and placed loosely
among the water, the particles are a long time subsiding, and are easily dis-
turbed after having settled. To clear the liquid it has been usual to add a few
shreds of isinglass or other animal gelatine. The inconvenience of this pro-
cess probably caused the introduction of the bag, which is however not without
some disadvantages; among which may be mentioned the trouble of cleansing,
and the imperfect solution of a portion of the extractive matter when the
coffee lies in so dense a mass. It has accordingly been suggested to place the
coffee between two flat perforated plates, at nearly the bottom of the vessel;
the water should be supplied by a tube extending from the top of the vessel to
the bottom, from whence it will ascend through the strainers, and the coffee
contained between them, which being unconfined, every particle will be kept in
agitation by the boiling water, and be thoroughly operated upon : to this
ºf ment the floating piston, before described, may be advantageously
aClCleCi.
Since the foregoing suggestions were made, Mr. Jones, of the Strand, has

COLCHICUM AUTUMNALE. 385
introduced a coffee-pot on the principle which is represented in the annexed
cut, a is a vessel placed over a lamp furnace, into which the requisite
quantity of water is put ; b is a double vessel, the
internal one consisting of a perforated metal cup to hold
the ground coffee; c is another recipient fitting over
b, and having a valve at d. When the water in a boils,
the steam ascends amongst the coffee in b : and when
the steam accumulates in sufficient force, its pressure
upon the surface of the water in a causes the boiling
fluid to ascend the pipe e e, and to be discharged into
the vessel c ; the lamp may then be blown out, and
the liquid will percolate through the coffee in a, and
the perforated strainer in its descent to the vessel a,
which will thus become filled with a filtered and
aromatic infusion.
COFFER. DAM. An enclosure constructed for the
purpose of laying the foundations of bridges, piers, &c.
formed by two or more rows of piles driven close
together, with clay thrown in between the rows, the
heads of the piles rising above high water mark, and
thus forming a barrier to exclude the water.
COHESION, or ATTRAction of Cohesion, is that
power by which the particles of bodies are held O
together. The absolute cohesion of solids is mea-
sured by the force necessary to tear them asunder; heat is excited at the same
time. At the chain cable manufactory of Capt. Brown, a cylindrical bar of
iron, of 1% inches diameter, was drawn asunder by a force of 43 tons. Before
the rupture the bar lengthened about 5 inches, and was reduced nearly three-
eighths of an inch at the part where the fracture took place, which became
heated to a degree unpleasant, if not painful, to the hand. The cohesive force
of metal is considerably increased by hammering, rolling, or drawing. The
following table shows the cohesive strength of a square inch in lbs. avoirdupois,
or the force necessary to pull asunder a square inch of the various substances
named therein.
Ö
2ſ.
<3
lbs.
Copper, cast . . . . . . . . 22,000
Ditto, wire . . . . . . . . . 61,000
Gold wire . . . . . . . . . 31,000
Iron, cast . . . . . . . . . 30,000 to 50,000
Ditto (German) . . . . . . 68,000
Ditto, bar . . . . . . . . . 60,000 to 80,000
Ditto (German) . . . . 60,000 to 90,000
Ditto, wire . . . . . . . . . 113,000
Platinum wire . . . . . . . . 56,000
Silver ditto . . . . . . . . . 40,000
Ash . . . . . . . . . . . 17,000
Beech . . . . . . . . . . 17,000
Deal (Norway spruce) . . . . . 18,000
Ditto (English) . . . . . 7,000
Elm . . . . . . . . . . . 13,000
Oak . . . . . 11,000 to 16,000
Hemp fibres glued together . . . . 92,000
COINAGE, or Corning, is the art of making metallic money. See MINT.
COLCHICUM AUTUMNALE. A medicinal plant, the vinous infusion of
whose root has been shown by Sir E. Home to possess specific powers of alle-
viating gout. The sediment of the infusion ought to be removed by filtration,
as it occasions gripes, sickness, and vomiting.

3S (; COMB MA KING.
COLLAR. A part of a horse's harness which surrounds his neck, and to
which the traces are attached by which he draws. It ordinarily consists of a
stuffed leather pad, on which rest two curved bars called the hames, united at
the lower ends by a few links of chain,
and drawn together at top by a strap S.-- 6°
and buckle; but from the collapsing of
// Q//*%-ll/ul) N.
the hames, the shoulders of the horses
frequently become rung, which induces
many to give the preference to breastings
rather than collars. In Mr. Lukin's
improved horse collars the hame is made
in one piece, which, from its elasticity,
has a tendency to expand instead of
collapsing, and the pads upon it are not
fixed immovably, but turn round upon
the hames as an axis, by which means
the pressure adapts itself to the motion
of the horse, and materially reduces the
chafing against his shoulders. The
annexed cut represents one of these
collars. a a represent the pads, one
turned partly round upon the hames
b b b to show their action; c. c are clips
for the traces; d a small pad which lies
over the horse's neck, and e the strap
by which the hames are contracted in
any required degree. -
COLOUR is that property in bodies which, when acted upon by light,
impresses the mind, through the agency of our sight, with those sensations which
we denominate colour. The light of the sun, which seems perfectly homogeneal
and white, is universally acknowledged to be composed of no fewer than seven
different colours, viz. red, orange, yellow, green, blue, purple, and violet. A
body which appears to be of a red colour has the property of reflecting the red
rays more powerfully than any of the others, and so of the orange, yellow,
green, &c. A body which is of a black colour, instead of reflecting, absorbs
all or the greatest part of the rays that fall upon it; and, on the contrary,
a body which appears to be white reflects the greatest part of the rays indis-
criminately, without separating the one from the other. See PAINTING and
PIGMENTs.
COMB MAKING. The process of comb making is usually conducted as
follows. The material of which the comb is formed is first reduced to thin
smooth plates of an even thickness. The workman who cuts the teeth then
fastens one of these plates in a clamp or vice, and proceeds to cut the teeth by
means of a double saw, of which each blade is somewhat like the small one
with which joiners and cabinet-makers cut their fine work. As this instrument
leaves the work square, and in rather a rough state, particularly in the inside
edge of each tooth, it is followed by another about the size and shape of a case-
knife, having teeth like a file on each flat side. After this, two others of the
same shape, but each finer cut than the former, follow. One stroke on each
side of the comb is then given with a rasping tool, to take off any roughness
that may remain on the sides of the teeth, after which they are polished by
rubbing them with rotten stone, and oil spread upon a piece of buff leather.
With the simple apparatus above described, delicate ivory combs, containing
from fifty to sixty teeth in the inch, are cut. Mr. Bunday's machine for cutting
the teeth of combs is constructed as follows: upon an arbor driven by a treadle,
is fixed a number of circular steel cutters, corresponding to the notches intended
to be cut in the comb. These cutters, which are about two inches diameter,
and all exactly equal in thickness, have brass washers between them, and are
also kept regularly asunder just above the place where the comb enters, by steel
guides fixed in a stationary frame. The comb is firmly secured to a horizontal


COME MA KING. 387
sliding block or carriage, which is made to advance towards the centre of the
~. Aº ‘is - ~~ ++ o-c ºx' ºn eans of a coyo ºr *** **n a 28 as #1, as 1--- l- > -- 4 -...- ?-,+r 3, . *
3.x:S C: &lic Cii Liv i ö, - J --- ~~~~~ * * * *** * * r *, *.*. L. A. A. V., vºl. v. M. º. 1 i V-2 A. 19 y 11 cl i 1 \li Ul Uy d, L) 3, 1] (Li-
wheel fastened upon its axis. The combs are pointed by applying them to an
arbor, driven by a crank, and clothed with cutters with chamfered edges.
Some improvements have been introduced in the rotatory comb cutting
machines by Mr. Lyne, who has also invented a machine by which two combs
are cut at once out of any tough material,
as horn or tortoiseshell ; the parts cut
out from between the teeth of one comb
forming the teeth of the other comb in the
manner shewn in the annexed diagram ; by
which means the waste of material occasioned
in cutting combs by the ordinary process is
avoided. This machine is represented in the
accompanying engraving. a a is the frame of
the machine, made of cast iron; b, a lever, which, by a pinion upon its axis, gives
i
f
º
º
F.--
g--------------------º-º-º-º:
an alternating motion to the racks c c, e is the cutter in its carriage, which is
attached to a strong helical spring, contained in the cylindrical box, and is
*


388 COMBUSTION.
seen immediately over it. At each extremity of the cutter is a small chisel
dd, set upon sliding rods, so that their distance asunder may be always equal
to the length of the cutter e, these chisels make the end cut, by which the teeth
of the one comb are separated from the back of the other comb. , Beneath the
cutters is a traversing carriage, upon which the horn or tortoiseshell is firmly
secured by screws: it is made hollow to admit of a heated iron being
introduced within it, in order to soften slightly the horn or tortoiseshell, and
render it less brittle. This carriage is advanced along a chase mortise, fixed
upon the bed of the machine by means of a screw, upon one end of which is a
ratchet wheel, which is moved by the compound levers i i i. The fineness of
the teeth of the combs is regulated by the teeth in the ratchet wheel, which is
accordingly changed with the nature of the work, and a handle is placed on the
axis of the ratchet wheel for the purpose of bringing back the frame after a
comb has been cut. The operation of the machine is as follows:—the alter-
nating motion of the lever b backwards and forwards alternately raises and
depresses the racks c c, the horns or curved projections in the middle of these
racks bring down the cutter e, by which one side of a tooth is cut, whilst the
extremities of the racks depress one of the chisels d, which makes the cut at the
end of the tooth. The cutter e is returned during the rise of the rack, by the
spring contained within the cylindrical box, and the chisels d by the spring of
the rods upon which they are set. In order to give the tapered form to each
tooth, and to reverse them successively upon the opposite side of each of the
racks to that shown in the engraving, is a small inclined plane or cam, which,
on the descent of the rack acting upon the vertical bars ff attached one to each
end of the cutter frame, causes the cutter to change its position, and to make
angular instead of parallel incisions.
COMBUSTION. The disengagement of heat and light which accompanies
chemical combination. Combustion was for a long time held to be the dis-
engagement or development of a certain air supposed to be contained in all
'combustible bodies, and to which the name of phlogiston was assigned; and
bodies which had undergone combustion were said to be dephlogisticated, or to
have parted with their phlogiston. This hypothesis, notwithstanding the
numerous facts at variance with it, and particularly the familiar one that
metallic oxides formed by combustion increase in weight, which could not be
the case if combustion consisted in depriving them of any substance previously
contained in them, was zealously maintained by many philosophers long after
the brilliant discoveries of Scheele, Cavendish, and Priestley, as to the nature
of atmospheric air, and against the theory of Lavoisier, founded upon these
discoveries, and upon Dr. Black's theory of latent heat. According to the
theory of Lavoisier, the light and heat emanate from the oxygenous portion of
the atmosphere at the moment of its fixation with inflammable bodies; and
succeeding chemists of his school, enlarging upon this idea, have ranged all
substances under two classes, viz. combustibles, and supporters of combustion.
But this theory, although much more consistent with most of the phenomena
of combustion, is still insufficient to account for some of them, and the dis-
tinction between combustibles and supporters of combustion appears to be
altogether imaginary, for one substance is frequently in both capacities, being at
one time apparently a supporter, and at another time a combustible. Thus,
sulphuretted hydrogen is a combustible with oxygen, and chlorine a supporter
with potassium; and sulphur, with chlorine and oxygen, acts as a combustible,
but with the metals it becomes a supporter. Nor can we ascribe the appearances
to an extrusion of latent heat in consequence of condensation: the protoxide
of chlorine, a body destitute of any combustible constituent at the instant of
decomposition, evolves light and heat with explosive violence, and its volume
becomes one-fifth greater; and the chlorates and nitrates in like manner treated
with charcoal, sulphur, or metals, detonate or deflagrate, while the volume of
the combining substances is greatly enlarged. Neither can the heat evolved
in combustion be attributed to a diminished capacity for heat in the resulting
substances, for in the greatest number of cases there is no diminution of capacity
of the compounds formed. For example, the combination of oxygen and
COMPASS. 389
hydrogen, or of sulphur and lead, produces no greater alteration in the capacity
of water, or of the sulphuret of lead, than the combination of oxygen with
copper, lead, or silver, or of sulphur with carbon, produces in the capacities of
the oxides of these metals, or of carburet of sulphur. The preceding, and
numerous similar facts, prove that combustion is not necessarily dependent
upon the agency of oxygen; that the evolution of the heat is not to be ascribed
simply to a gas parting with its latent store of that ethereal fluid on its fixation
or combustion; and that no peculiar substance, or form of matter, is necessary
for producing the effect, but that it is a general result of the actions of any
substances, possessed of strong chemical attractions, or of different electrical
relations; and that it takes place in all cases in which a violent motion can be
conceived to be communicated to the corpuscles of bodies. For this view of
the subject the world is indebted to the masterly mind and deep and successful
researches of Sir H. Davy. . For a clear and comprehensive account of his
experiments connected with this subject, together with his inferences therefrom,
we refer the reader to Dr. Ure's Chemical Dictionary.
COMPASS. A nautical instrument, showing the direction in which a vessel
is sailing, or the part of the horizon to which her head is directed. It consists
of a flat bar of steel, which being repeatedly rubbed with a magnet or loadstone
acquires the property of constantly taking a direction nearly corresponding with
the meridian, when freely suspended from a thread, or upon a delicate pivot.
Although as important consequences have flowed from the invention of the
compass as from any other invention whatever, the name of the author of it,
and even the age and country in which it had its origin, are points involved
in the greatest obscurity. In Europe we are indebted for its use to
B. Givaia, of Naples, who, towards the close of the twelfth, or about the
commencement of the thirteenth century, observed that iron became polarized
by contact with the loadstone; but most writers upon the subject agree that the
compass was known long before that period to the Indians and Chinese; nay,
in Bowles's Spirit of Maritime Discovery, it is attempted to be proved, by much
“learned argument,” that it was known to Noah, and formed part of the
equipment of the ark. The compass is extensively used in surveying and
mining, as well as in navigation; but there is in general this difference between
them, that marine compasses have a circular card divided into thirty-two
parts or points, and attached to the needle; but in those for other purposes
the card is fixed to the bottom of the box, which is turned till the needle coincides
with the north point of the card. Marine compasses are usually supported
upon a pin of steel or brass, having a fine point, working in a socket of agate
let into the centre of the needle or magnetized bar; the pin is fixed into the
bottom of a circular box or basin, which is suspended by two pins turning in
holes in a ring concentric with the circular box; this ring again is suspended by
two pins at right angles to the former, the whole forming a universal joint.
Besides the steering compass, there is another one made use of at sea, for
the purpose of taking the sun's bearing, in order to ascertain the variation of
the compass, or the difference between the true and magnetic north points, as
also in taking the bearings of different objects in marine surveying; this is
called the azimuth compass. The card, besides the thirty-two points, is accu-
rately divided at the circumference into 360 degrees, and on the opposite sides
of the compass-box are two sights, for taking accurately the bearing of an
object, and a stud for stopping the card at the instant the bearing is obtained,
so as to allow time for reading off the angle. The circular box is suspended
within a square box, which latter is supported upon a pivot (on the top of a
three-legged stand), so that the right vanes may be turned to any part of the
horizon. Captain Phillips, R.N. has taken out a patent for an improved mode
of mounting ship's compasses; the object of which is to prevent those derange
ments which sudden concussion occasions to these instruments, by which the
card is frequently thrown off its central pivot, as is sometimes the case in stormy
weather, or from firing guns, striking of steam-boat paddles, &c. The figule
in the following page, Fig. 1, gives a vertical section of the improved compass. a
is the standard formed of a hollow tube which incloses a long spiral spring, resting
3 D
390 COMPASS.
upon a bearing at b; to this bearing are fixed two handles c c, by which it may be
elevated within the standard, (compressing the spring,) and the bearing may rest
Fig. 1.
#
|
t
t
t
º
º
#. #
º |
*
|
* =
at any on the notches or recesses Nos. 1,2,3,4, which are formed in opposite sides
of the tube, to receive the handles ce. d is a short solid cylindrical piece, so fitted
into the hollow standard as to slide freely within it, and resting upon the spiral
spring; e is a cap fixed on to a by a bayonet joint, to prevent the spring from
forcing the sliding piece d out of the standard; f is the compass-card, which
rests upon the pivot g; this pivot passes through the cross bars l l, and the
lower end is formed into a spherical knob, (better seen at h, Fig. 2, which
exhibits the same parts upon a larger scale). This spherical knob rests upon a
flat surface of agate, cornelian, or other hard stone i, which lies in a recess
upon the top of the piece d, and is kept in its place by the cap k being screwed
down upon it; the cap k is made concave in the upper part of it, to fit the
spherical knob, so that the latter, resting at bottom upon a hard plane, and
above in its hemispherical concavity, can turn freely in any direction. At m m
is shown (black) the section of a leaden ring, which surrounds the compass-
box, as is shown by the two parallel dotted lines. At n n are two handles
fixed to the leaden ring, by which it may be shifted higher or lower on the
case, and be fixed at any height at pleasure, by the palls o o dropping into the
racks p p, which are screwed to opposite sides of the case. . q is the steering,
or “lubber's point,” which is suspended upon a movable joint r as a centre of
motion, and oscillates as a pendulum. This centre being placed so as to slide
between two vertical guides, it may be raised or lowered at pleasure, and is
retained in its place by the pressure of a spring in the centre. The lubber's
point should be adjusted so as to be even with the upper edge of the compass,
by raising or lowering the centre r, and the bob s should be shifted along the
rod until it coincide with the centre of the leaden ring. If the motion of the
compass-box, in a vertical direction, should be too violent, it is to be checked
by raising the handles c c into one of the notches 1, 2, 3, 4, as may be required
by circumstances. The oscillations of the compass-box are regulated by shifting

COMPOSITION OF FORCES 391
the leaden ring, raising it in blowing weather,
and lowering it in fine weather. It frequently
happens at sea that the sun is visible, although
the horizon cannot be distinguished for fog and
haze, in which case it becomes impracticable
to take the sun's altitude, in order to determine
the ship's place. This circumstance, at all
times inconvenient, may, in some situations,
be attended with the most fatal consequences.
To obviate this difficulty, Lieut. G. Linde-
say, R.N. proposes to take two bearings of the
sun, as near noon as possible, noting the time
elapsed by a good watch, and from these data
to compute the sun's meridian altitude in the
usual way, which will give the latitude and
apparent time at the ship; , and this latter,
compared with the Greenwich time, will give
the longitude. For taking the sun's bearing
he proposes to attach to a common compass,
mounted on a pivot at the summit of a tripod,
a telescope, turning upon a joint, and a mag-
nifying glass to read off the divisions, as
shown in the annexed diagram. It appears
to us that the common azimuth compass (with
which all ships are or ought to be provided,)
will be found much superior to the above
contrivance, by which we fear it would
be difficult to observe the bearing with
sufficient accuracy.
COMPASSES (MATHEMATICAL). Instru-
ments for describing circles, measuring lines,
&c. They are of various descriptions; the common consist of two sharp-
pointed branches or legs, turning upon a hinge at top. Triangular compasses
are constructed as the ordinary compasses, with the addition of a third leg
turning upon a universal joint; they are used in laying down places on a chart,
or measuring angles.
Beam Compasses are for the purpose of describing circles of considerable
radius, and consist of a straight bar of wood or metal, of suitable length,
furnished with a fixed point as a centre, and a movable tracing point, which
... may be set to any required radius.
Elliptical Compasses, likewise called a “trammel,” for the purpose of describing
ellipses, consist of a bar with a fixed tracing point, and two cursors, which can
be set upon any part of the bar, and which have a sliding motion in two grooves
cut in a piece of brass, which grooves intersect each other at right angles.
Proportional Compasses are composed of two flat bars pointed at the end,
and having a groove down the middle, in any part of which can be set a steel
pivot, held fast by a tightening screw, by which means the compasses can be
divided into two parts, bearing any required proportion to each other, and
which, turning upon the pivot in the manner of a pair of scissors, the angles
at the opposite extremities will be proportional to the length of the respective
arts.
COMPOSITION OF FORCES is the finding a single force which shall be
equal to two or more given forces when acting in given directions, the principles
of which may be thus illustrated. If two forces, moving in the direction of the
two adjacent sides of a parallelogram with velocities proportional to the length
of the sides of the said parallelogram, impinge upon a body, it will cause that
body to move over the diagonal of the parallelogram in the same time that
either of the forces singly would have impelled it along its corresponding side.
This may be demonstrated experimentally by an ingenious apparatus, designed
and executed by Mr. C. Holtzapfell, of Charing-cross, and which is exhibited

392 CONDENSER
in the annexed engraving.
The apparatus consists of a
rectangular board, with a
perpendicular brass pillar
fixed in one corner. Two
#. steel wires extend
om the flanch at the bot-
tom to the cap at the top,
and sufficiently distant from
the pillar to allow the two
ivory balls a and b to descend
upon them without touching ſº,
the pillar. The board is
made perfectly flat, var-
mished, and polished, and
when used, must be placed
perfectly level. At the point
where two straight lines from
the bottom of the guide wires would meet and make a right angle, a small
hollow is made to receive a ball c. The weights of the balls a and b are
adjusted to correspond with the length of the sides of the board; so that when
the ball a is dropped, it will give an impulse to the ball c, and send it to the
end of the board in the direction of the line d in the same time that the ball b
would send it to the edge of the board in the direction e. If now both balls be
dropped at the same instant from the same height, they will propel the ball in
the diagonal c fof the parallelogram in the same time that one of them singly
would have impelled it along one of the sides.
COMPRESSIBILITY, in Philosophy, that quality of a body by which it
yields to the pressure of another body, so as to be reduced within a smaller
compass. The compressibility of liquids is still a matter of doubt with philo-
sophers, although some consider the fact proved by the experiments of Mr.
Canton, and, more lately, of Mr. Perkins. According to the former gentleman,
the compression of
66
e e º Or º º
Spirits of wine, spec. grav. 846 was i.75 Parts
4. 46
Rain water . . , , 1000 . 1,000,000 *
3
Mercury . . . , 13,595 . . 1,000,000 "
CONDENSATION. The art by which a body is rendered more dense,
compact, and heavy. Condensation is by most writers distinguished from
compression, by considering the latter as effected by mechanical force or pres-
sure, and the former by cold, or the abstraction of heat.
CONDENSER. A vessel in which aqueous or spirituous vapours are
reduced to a liquid form, either by injection of a quantity of cold water, as in
the condenser of a steam-engine; or when this is inadmissible, as in the case of
alcoholic vapour, by placing the condenser in another vessel, through which is
maintained a constant current of water, the condenser being so constructed as
to expose the steam or vapour in thin strata over an extended surface to the
action of the cooling medium. The condensers employed by distillers are
usually composed of a long tube of pure tin, or of copper tinned, formed into a
series of concentric coils over one another, and from its shape denominated a
worm; this is placed in a large vat, which is called the worm-tub. But when
the distillation is carried on upon a large scale, the worm is not of a cylindric
section, as it is not the form which is best adapted for the purpose of conden-
sation; for on account of the large diameter of the tube, which them becomes
necessary, that portion of vapour which occupies the centre of the tube is not
brought into sufficiently intimate contact with the cooling surfaces, and there-
fore either escapes condensation, or requires a much larger quantity of water
than would be otherwise necessary. Various arrangements have, in conse-

CONIC SECTIONS. 393
quence, been devised for presenting the vapour in extremely thin strata, so as
to obtain a ready condensation with the least quantity of water. One invented
by Mr. Wheeler, of High Wycomb, appears to us very judiciously arranged for
this purpose; it is denominated by the inventor the Archimedes' Condenser, and
is represented in the accompanying en- *=-º-º-º-
graving, a is the pipe leading from the -
neck of the still, through which the
vapours enter into the flat chambers b b
(represented black). These chambers,
owing to the sectional view, appear to
be disconnected, but they are wound
spirally round a central tube, and termi-
nate at the cock c, where the condensed
products pass off; d is a pipe leading ‘. . . ;
from a reservoir of cold water to the I-
bottom of the central tube, where it |+-
passes through holes represented at e e = {-, - . . . .2
underneath the vapour chambers, and - -
can only ascend in the vessel by passing
successively through every coil, as each -
turn of the spiral is connected by the ==
edge of one of its plates to the side of . . . . . . .
the containing vessel. The water thus
heated in its progress flows out at the
aperture f into a trough or pipe. By
this arrangement it will be noticed that
the hot vapour or fluid is constantly
descending spirally an inclined plane,
while the cold fluid is constantly ascend-
ing, almost in contact with the other, as
they are only separated by a very thin
plate, formed of the best conducting
substance (copper). It will likewise be
evident that two fluids, one cold and the
other hot, may thus be made to exchange their temperatures. Thus, if cold
water at 500 Fahr. be admitted at the bottom of the vessel, it will, when it
arrives at the top, be nearly of the same temperature as the vapour or liquid
(say 2000), which entered at the top, by having gradually abstracted the heat
from the vapour or hot liquid in its progress. This being understood, it follows
that the latter, having gradually parted with its heat in its descent, will become
of the same, or nearly the same temperature at the termination of its course
as the water, namely 509, provided the liquids be admitted in their proper
volume, which is easily regulated by the cocks.
CONE. A geometrical figure generated by the revolution of a right angled
triangle upon one of its short sides, as an axis.
CONGELATION. The transition of a liquid to a solid state, in conse-
quence of the abstraction of heat: thus metals, oil, water, &c., are said to
congeal when they pass from a fluid to a solid state. With regard to fluids,
congelation is the same as FREEZING, which see.
CONIC SECTIONS are the figures formed by the cutting of a cone by a
plane; they are five in number, corresponding to the different positions of the
cutting-plane. When the cutting-plane passes through the apex of the cone,
and coincides with the axis, the section is a triangle. When the plane cuts the
axis at right angles, the section is a circle. When the plane cutting the axis
obliquely, and passing through both sides of the cone, the section is an ellipsis.
When the plane cuts the axis in a line parallel to one side of the cone, the
section is a parabola : and lastly, when the plane either does not cut the axis,
or cutting it forms with it an angle less than that formed by the side with it,
the section is an hyperbola. The term conic section is applied more peculiarly
to the three last figures; and the doctrines of their several properties constitute
F
>;
-
-º:-
|
|--
-
||||





394 COOPERING.
one principal branch of geometry, of great importance in astronomy and many
other sciences. See GEOMETRY.
CONOID. A solid produced by the circumvolution of the section of a
cone about its axis, and consequently may be either an elliptical conoid (other-
wise called a spheroid), a hyperbolical conoid, or a parabolical conoid.
CONTRACTED VEIN, in Hydraulics, a term denoting the diminution
which takes place in the diameter of a stream of water issuing from a vessel at
a short distance from the discharging aperture, owing to the particles nearest
the periphery experiencing greater attrition than the rest, and being retarded :
in consequence of which the least diameter of the stream is to the diameter of
the orifice, on an average as 1 to the square root of 2; and in computing
the discharge of fluids, this proportion should be substituted for the real
aperture.
ºr ATE WHEEL, or CRowN WHEEL. A wheel in which the teeth do
not radiate from the axis, but stand at right angles to the arms, or parallel to
the axis. It is chiefly used for clock-work.
COOLER, among brewers, distillers, &c. is a large shallow vessel in which
liquids are exposed to cool.
COOPERING is the art of manufacturing casks, barrels, vats, and all kinds
of circular or elliptic wooden vessels, that are bound together by hoops. There
are several classes of coopers, some of whom carry on their peculiar branches
distinctly, while others embrace the general manufacture in one establishment.
The workmen, however, generally confine themselves to the particular line they
have been brought up to, and in which they are consequently most expert.
Thus we hear of “butt coopers,” “rundlet coopers,” “dry coopers,” “white
coopers,” and “wine coopers.” The work of the butt coopers chiefly consists
in the manufacture and repair of casks for breweries, also puncheons and
hogsheads. Their principal tools are very few, but they use these with so much
dexterity and skill as to produce with surprising facility and dispatch the most
solid, accurate, and substantial work. With an axe, an adze, two or three
spoke shaves, and a bench, the cooper rapidly gives a new and perfect form to
the material he operates upon. The bench consists simply of a stout plank 4 or
5 feet long, and 1 foot wide; it stands upon four feet, but considerably inclined,
one end of the bench being usually about 2 feet high, and the other 6 or 8
inches lower. On the bench are fixed “stops" and “keeps,” for the purpose of
holding the staves or other work. This cooper has also a large plane, called a
jointer, which is usually fixed with its face upwards, and against which he forces
the staves to shoot their edges to a smooth surface, (whether those edges are
required straight or curved,) in order to make the “joints" or joinings of the
staves come into perfect and hardly-pressed contact, when they are brought
together to form the vessel. To describe all, or even the leading operations, of
the cooper, would be uninteresting, because it is so openly and universally prac-
tised. We shall therefore proceed to notice, and that briefly, the nature of the
occupations of the other classes of coopers mentioned; and afterwards we shall
insert some patented improvements in the art, that appear to be deserving of
notice. The rundlet coopers make use of the same tools, or nearly so, as in
the branch of the trade last described, but of less dimensions. Their work
consists chiefly in the manufacture of bottles, and small casks, for holding the
products of the distilleries, besides numerous other purposes. The dry coopers
are employed in manufacturing sugar hogsheads, and casks of every size and
quality, for holding dry goods; and as such vessels are seldom required air and
water-tight, the workmanship is comparatively coarse to that of the butt and
rundlet coopers, and the expense proportionally less. The white coopers manu-
facture all kinds of domestic utensils, such as are used for brewing on the small
scale; for washing tubs, churns, pails, and a great variety of other work. To
this branch of coopering is frequently added the coarser kinds of turnery for
domestic use. The wine cooper's business consists chiefly in the removal and
depositing of wines and spirits, which he is enabled to effect with greater security
and convenience than other persons, who are not so intimately acquainted with
the nature and strength of the vessels containing them. The bottling, storing,
COOPERING. 395
and packing of wines, and other liquors, belong to this branch of trade, besides
the making of all repairs and alterations in the butts or casks which may be
found necessary. Although the manufacture of backs and vats appears of a
similar character to other coopering, yet it is usually made a distinct branch of
business, and is performed by persons who call themselves back and vat makers.
From the variety of forms, and the immense strength required for some of the
backs, as well as for the frame-work to support them, the knowledge and skill
of the carpenter is almost constantly required, and not unfrequently the aid of
the engineer. In America, and several parts of Europe, machinery has been
extensively introduced to facilitate the labours of the cooper. In 1811, a patent
was taken out by Messrs. Plasket and Brown for the following mode of
operating; and as the exclusive privilege granted to those gentlemen is expired,
those of our readers who may be so disposed are at liberty to adopt the mechanism
employed, which is thus described in Dr. Gregory's Mechanics.
* First, the machinery for cutting the stave consists of a stout bench, having
a board or platform annexed to it, capable of being moved end ways, to which
another board is connected, so arranged as to be moved across steadily by
racks and pinions, or screws. The last board has a hollow part made in it, in
which the stave-board may be laid, so that one edge of it may project clear
beyond the edge of the first-mentioned board; a circular saw is placed either
above or below the bench, having its axis at right angles to the line of motion
of the first mentioned board, and opposed to the direction of the course of the
projecting part of the stave-board; this circular saw is made flat when the
straight-edged staves are to be cut, and is dished, or of a spherical shape,
when staves with curved edges are wanted. The board first mentioned is moved
either in a right line, or is made to assume a curved course, by being confined
in its motion by curved grooves, or by curved rods moving against pins; and
by the proper management of these sliding-boards, the stave-board is cut by
the circular saw of the shape desired. The machinery next used consists of
a large lathe, in which the cask is turned in a vertical position when it is of a
large size (after it is formed in the usual manner from the staves prepared as
above described), being either fixed in a great chuck placed beneath it, or in a
cylindrical cage which surrounds it, fixed upon a strong upright arbor, and
revolving between collars, where it serves the office of a mandrill In this
lathe the chime and groove for receiving the head are turned in the cask by
the application of a proper tool. When the cask is small, the cage is made to
turn in a horizontal position instead of revolving vertically. . The third opera-
tion is to form the head, which is pinioned together as usual, after having the
pin-holes made by piercers projecting from the mandrill of a lathe, , the dis-
tances and depths of which holes are correctly regulated by gauges; it is then
turned on a flat revolving table, from which points project to hold it fast, and
against which it is held by another revolving piece that is screwed towards the
first, where it is brought to the proper size of the cask by fit tools. The fourth
operation is to turn the whole cask at the outside, for which purpose it is placed
in a large lathe between two chucks, made to fit into the chines, and attached
to the head by points; and then the surface of the cask is turned smooth by a
spokeshave, or other fit instrument, held against it by a rest properly placed for
the purpose. The patentees bend their wooden hoops for their casks in an
expeditious manner, by fastening one end of them to the circumference of a
wheel, and pressing them against the wheel as it is turned round; they also
describe a method of forming the projecting part in the bung-staves of the
small casks called bottles, by flat or concave circular saws, which cut the face
of the stave on each side close up to the projection ; and lastly, in giving
motion to this machinery, the inventors use any of the usual first movers and
millwork as may be necessary.”
It is due to Mr. George Smart, of Westminster Bridge, to state, that, for
some years previous to the date of the patent granted to Messrs. Plasket and
Brown, he had in actual operation, on a very extensive scale, a similar arrange-
ment of machinery for making small casks, particularly canteens for the army.
The saws and other apparatus were of course more diminutive, but the accu-
396 COPPi.R.
racy of their work may be judged of when it is stated that there was no occa-
sion to plane the edges of the staves to render the bottles water-tight, although
submitted to a severe test.
COPAL. A hard, shining, transparent concrete juice, obtained from an
American tree; but which, although it is commonly considered a gum, has
neither the solubility in water common to gums, nor the solubility in alcohol
common to resins, except in a very slight degree. It may be dissolved by
digestion in linseed oil, rendered drying by quick lime, with a heat very little
less than is sufficient to boil or decompose the oil. This solution, diluted with
oil of turpentine, forms a beautiful transparent varnish, which, when properly
applied, and slowly dried, is very hard and durable. It preserves and gives
lustre to paintings, and greatly restores the decayed colours of old pictures, by
filling up the cracks, and rendering the surfaces of reflected light more
uniform. It has been observed by Mr. Sheldrake, that if powdered copal be
triturated with a little camphor, it softens and becomes a coherent mass; and
camphor, added either to alcohol or oil of turpentine, renders it a solvent of
copal. Half an ounce of camphor is sufficient for a quart of oil of turpentine,
which should be of good quality; and the copal, about the size of a walnut,
should be broken into small pieces, but not to powder. The mixture should
be set on a fire, so brisk as to make it boil almost immediately. The
vessel should be of metal, strong, with a long neck, and capable of holding
about two quarts. The mouth should be stopped with a cork, having a
notch cut in it to prevent its bursting. Mr. Cornelius Varley (who has
bestowed much judicious attention to the preparation of artists' materials), states
that a good copal varnish may be prepared by pouring upon the purest lumps
of copal, reduced to a fine mass in a mortar, colourless spirits of turpentine, to
about one-third higher than the copal, and triturating the mixture occasionally
in the course of the day. Next morning it may be poured off into a bottle for
use. Successive portions of oil of turpentine may thus be worked with the
same. Oil of lavender is stated to be alone a solvent of copal, which is probably
owing to the camphor contained in the former. Camphorated oil of turpentine
will also dissolve copal, but a mixture of camphor and alcohol effects it more
readily.
COPPER is a metal of a reddish brown colour, hard, very malleable, ductile,
and sonorous; of considerable tenacity, and of a specific gravity from 8.6 to 8.9.
The good quality of copper is shown by its capability of alloying silver, without
any diminution of its extensibility under the hammer or roller. For this reason
the Swedish copper has a decided preference in the preparation of the alloys
of gold and silver; and its superior purity has been found to render it far more
durable when employed in the sheathing of ships, as well as for many other
}. English copper is chiefly obtained from the mines of Cornwall and
evonshire, whence it is usually transported across the Bristol Channel to be
smelted at the coal-works in South Wales. The ores consist chiefly of yellow
copper ore, or copper pyrites, and the grey sulphuret of copper. The average
produce in copper is said to be about 83, parts from 100 of the ore. The
ordinary processes of smelting consist of alternate calcinations and fusions in
reverbatory furnaces of the usual construction. The calcining furnaces are
furnished with four doors or openings, two on each side, for the convenience
of stirring the ore and drawing it out of the furnace. They are commonly
from 17 to 19 feet in length from the bridge to the flue, and from 14 to 16
feet in width, with a fire-place 5 feet by 3. The melting furnaces are usually
about one-third the area of the calciners, but their fire-places are nearly as
large, and they have only one door, and that in front. The charge of ore for
a calcining furnace usually consists of about 3 tons, which is uniformly dis-
tributed over the bottom. When charged, the heat is gradually increased
during twelve hours, until near the point of fusion, when the ore is discharged
through holes in the bottom, and is suffered to lie underneath until it is suffi-
ciently cool to be removed. With this calcined ore, which is in the form of a
black powder, the melting furnace is charged, by spreading it over the bottom
thereof. A few slags from the previous fusions are added, and the door
COPPER, 397
is closed and luted. When brought into fusion, the liquid mass is well
stirred, and the oxides and earthy matters which float at the top are skimmed off
through the front door by the smelters. When this first mass of metal has been
freed from the last-mentioned impurities, the smelter lets down into the furnace
a second charge of calcined ore, and proceeds with it in the same manner as
with the first, repeating the charges until the furnace will hold no more, when
a tapping-hole made in the side of the furnace is opened, and the metal runs
through it into a pit filled with water, which causes the metal to become granu-
lated, in which state it contains about one-third part of copper. The slags
which have been cast in sand-moulds, are afterwards broken to ascertain if
they contain any metal ; the pieces that do are then remelted to separate it.
When the ores are difficult of fusion, some fluor spar is added to the charge.
The coarse metal obtained by the preceding process is then calcined by a similar
treatment to that which the ore received. To oxidize the iron with which the
copper is contaminated, the charge is allowed to remain twenty-four hours in the
furnace, where it is repeatedly stirred and turned. The metal thus calcined is
then to be melted again with some slags from the previous melting, to which
may be added some pieces of furnace bottoms, which are impregnated with the
metal. The slags from this operation are also skimmed off; they have a great
specific gravity, being composed chiefly of the oxide of iron; they fuse readily,
and act as fluxes to reduce further portions of the ore. The metal obtained
from the second operation of the melting furnace, after the slag has been
separated, is tapped off either into sand-moulds or into water. In the former
plan the product is collected in a mass, and is called blue metal; in the latter it
becomes granulated, and is denominated fine metal. The quantity of pure
copper these products contain is about 60 per cent. The subsequent calcination
and fusion of these last products is conducted by a repetition of the operations
described ; and the º of this third melting are pigs containing from 80 to
90 per cent. of pure metal. The fourth process is, for the most part, an
oxidizing, or, as it is called, a roasting of the pigs obtained in the third. For
this purpose the furnace is filled with the pigs to the extent of 25 or 30 cwt.
which are exposed to the action of the air, while the heat is gradually increased
to the melting point, which facilitates the expulsion of the volatile matters, and
oxidizes the iron or other metallic substances that may remain. This operation
is continued from 12 to 24 hours, according to the degree of purity of the
pigs when put into the furnace; and when completed, the metal is brought to
a state of fusion, and run out into sand beds, The ebullition of the metal
arising from the extrication of the expanded air from the sand under the
metal, caused the latter to assume in cooling a honey-comb texture internally,
with a blistered surface; and, from this latter appearance, such copper is
denominated blistered copper. The copper in this stage being freed from its
more abundant contaminations is ready for the refining furnace, which is of a
similar construction to the melting furnace, only that the bottom, instead of
being of fire-brick, is a bed of sand, laid to incline to the furnace door, near
to which a pool is formed for the purpose of lading out the refined copper.
The furnace is charged with from three to five tons of the blistered pigs; the
heat applied to them is at first moderate, and air is admitted so as to continue
the oxidation, should the metal not be quite fine. When this charge is fused,
and the slags skimmed off, an assay is taken by the refiner with a small ladle,
and the metal broken in a vice. From the appearances of the metal both in and
out of the furnace, the refiner judges whether it is in a sufficiently forward state
to undergo the toughening process; previous to which the copper is of a deep
red colour, inclining to purple, with an open crystalline structure. In the pro-
cess of toughening, the surface of the metal is first covered over with charcoal;
a pole, commonly of birch, is then held in the liquid metal in the furnace, which
causes considerable ebullition, owing to the evolution of gaseous matter; and this
operation of poling is continued with the occasional addition of fresh charcoal,
until the quality of the assays, which the refiner takes from time to time, attain
the required degree of purity indicated by the polished silky appearance of the
metal when cut half way through, the light red colour of it when broken, and
3 E
398 COPPER.
the closeness of the grain. After this a trial of the malleability of the copper
is made by taking out a small quantity in a ladle, casting it in a metallic
mould, and then hammering it out upon an anvil: if it does not crack at the
edges by this operation, it is deemed in a fit state to be withdrawn from the
furnace, which is done by lading it out and casting it into rectangular cakes, 12
inches wide by 18 inches long. In preparing copper for the manufacture of
brass, it is usual to granulate it by pouring the hot metal through a colander
placed over a cistern of cold water, which causes the drops of metal to assume
by contact with the cold fluid, a ragged appearance, and to which the name of
feathered shot is given in the trade. For making brass that is to be drawn into
wire, the same process as the last is employed, except that the metal is poured
into hot water; the drops, in consequence, take an oblong form, and are hence
termed bean shot. In granulating copper, it should be poured into the water by
small quantities at a time to prevent explosions. A considerable quantity of
copper is exported by the East India Company under the denomination of
Japan copper. It is cast in small sticks about six inches long, and weighing
about half a pound each. It is of a rich red colour, caused by throwing the
cast sticks, as soon as they have become solid in their moulds, into water.
Copper unites readily with several of the metals. Its combination with tin is
effected at a less heat than is necessary to melt the copper; on which circum-
stance is grounded the method of tinning copper vessels. For this purpose
they are first scraped or scoured, and afterwards rubbed with sal ammoniac.
They are then heated (usually over a charcoal fire), and sprinkled with pow-
dered resin, which defends the clean surface of the copper from acquiring the
slight film of oxide that would prevent the cohesion of the tin to its surface.
The melted tin is then poured into the vessels, and spread about. An extremely
small quantity adheres to the copper, which is supposed to be sufficient to
prevent the noxious effects of the copper. When tin is melted with copper,
it forms the ancient compound termed bronze, the specific gravity of which is
remarkable for being greater than would be deduced by computation from the
bulks and specific gravities of its component parts. The uses of this hard,
sonorous, and durable composition, in the fabrication of cannon, bells, statues,
and other articles, are well known. The ancients made cutting instruments of
this alloy. A dagger analysed by M. Hielm consisted of 83% copper, and 16;
tin. Copper unites with bismuth, and forms a reddish white alloy. With
arsenic it forms a white brittle compound called tombac ; with zinc it forms
the important compound called brass; and it is distinguished by various other
names, according to the proportions of the two ingredients. It is not easy to
unite these two metals in considerable quantities by fusion, because the zinc is
volatilized at a heat inferior to that which is required to melt the copper, but
they unite very well in the way of cementation. There are various ways of
uniting granulated or small pieces of copper with zinc, but the following is the
ordinary method adopted in this country. Calamine, which is an ore of zinc,
is calcined in a kiln, or made ret hot, then ground to powder, sifted fine, and
mixed with ground charcoal, as the calamine is apt to clod and prevent an
uniform admixture. About seven pounds of calamine are put into a melting
pot of about a gallon content, to which are added about five pounds of the
granulated copper; the calamine must be mixed with as much charcoal as will
fill the pot, and the copper must lie uppermost. This is let down with tongs
into a wind furnace, 8 feet deep, where it remains 11 hours. One furnace
usually holds eight pots arranged in a circle round a grate. By the heat the
zinc becomes revived, rises in vapour, and combines with the copper, which it
converts into brass. Towards the end of the process the heat is suddenly
raised, which causes the brass to melt and occupy the lower part of the
crucible. After melting it is cast into plates or ingots for use, as it is required.
The following method of making brass, mentioned by Cramer, is recommended
by the scientific Dr. Ure. The powdered calamine being mixed with an equal
quantity of charcoal, and a portion of clay, is to be rammed into a melting
vessel, and a * of copper, amounting to two-thirds of the weight of
calamine, must be placed on the top, and covered with charcoal. By this
COPY ING PRESS. 399
method the volatile zinc ascends and converts the copper into brass, which
flows into the rammed clay; consequently, if the calamine contain lead, or
any other metal, it will not enter into brass, the zinc alone being raised by the
heat. Copper unites readily with antimony, a compound of a beautiful violet
colour. It does not readily unite with manganese. With tungsten it forms a
dark brown spongy alloy, which is somewhat ductile. See Alloy.
COPPERAS. A name apparently given by persons ignorant of its true
nature, to the sulphate of iron, obtained by the decomposition of iron pyrites.
The English copperas, or green vitriol, as it is also called, is made from the
natural combination of iron with sulphur, known in the various places where
they are found, by the several names of copperas stones, horse gold, gold
stones, &c. These are collected in great quantities, and laid in heaps about two
feet thick, upon a clay floor, surrounded by boards, that direct the rain water
that falls upon them to flow into a cistern. The clay floors at some works are
100 feet long, 15 broad at top, but narrowing to 12 at bottom, as they shelve
gradually to allow the water to run off easier. The cistern usually contains
about 100 tons of water. The copperas stones lie 5 or 6 years before they
yield a strong liquor. The sun and rain are found to be the proper agents; and
that other water, although prepared by exposure to the sun, and sprinkled on
them, only retards the produce. After a time these stones change to a vitriolic
earth, which swells and ferments like leavened dough. When a new bed is
made, the work is hastened by mixing a good quantity of the old fermented
earth with the new stones; and when this has come to perfection, it is refreshed
every fourth year by a layer of fresh copperas stones on the top. The copperas
water is considered rich if it weigh fourteen-eightieths more than water. The
copperas liquor is boiled in leaden vessels, containing about twelve tons. About
a cwt. of old iron is put into it at first, and more added as it dissolves,
amounting, in one boiling, to about 15 cwt. Fresh water from another boiler
is added to supply the loss from evaporation. When the boiling is finished,
(which is determined by the deposition of crystals in a little earthen vessel,
after a small quantity has been allowed to cool therein,) the liquor is drawn off
into a tarras cistern 20 feet long, 5 feet deep, 9 feet over at top, but tapering
towards the bottom, where, being left for a fortnight to cool and crystallize, the
remaining liquor is drawn off, and is reserved for boiling with new liquor.
At the bottom and sides of the cistern or coolers there is usually a crystalline
deposit 5 inches thick,--that at the sides being of a bright colour, while that at
the bottom is foul and dirty. At some works, instead of putting all the iron
into the boiler, a portion of it is added to the liquor in the cistern before
boiling. When the pyrites is too abundant in sulphur, and does not alter by
exposure to the weather, it is usual to roast it in piles to drive off the super-
abundance; and when the sulphur is required as a separate product, to distil
the pyrites in close vessels. Copperas is also formed by simply exposing some
kinds of bituminous earth to air and moisture, from which the crystals are
afterwards obtained by washing. The French also manufacture copperas by
dissolving old iron in weak sulphuric acid, and crystallizing the solution.
Copperas crystallizes in the form of rhomboidal prisms, which are transparent
and of a beautiful green colour. Its taste is harsh and styptic; it reddens
vegetable blues; two-thirds of cold water, or three-fourths of boiling water,
dissolve it. A moderate heat calcines and whitens copperas, by driving off the
water of crystallization; a greater heat expels the sulphuric acid. Its con-
stituents, according to Berzelius, are 28.9 acid, 28.3 protoxide, and 43 water;
according to Mr. Perret, 1 prime acid, 2 oxide, and 7 water. The chief uses
of copperas are the making of ink and in dying,
COPYING PRESS. A machine for speedily producing a fac-simile copy
of any manuscript recently written. The method is to place over the letter a
sheet of thin damp paper, and subject them both to the action of the press, by
which means a portion of the ink is transferred from the manuscript to the damp
paper. When letters are intended to be copied by this means, it is usual either
to make use of a kind of ink expressly prepared for the purpose, or to add a
portion of sugar to the common writing ink. The presses are variously con-
400 CORAL.
structed; but the screw press, now so common in merchants' counting-houses,
is the invention of the celebrated James Watt, who obtained a patent for it
about forty years ago. The annexed figure represents an improvement upon
this machine, invented by Mr. Ritchie, of Edinburgh, a the bed of the press;
----'ºrº * *** - -
t 8
*
} t
f 3.
*
} : *
t
i : ;
s *
t
g
ñº |- º '
i. TH- ſi
| º =mElſt tiſſiºmº.
i. 7 -
iſi liń. | - Fºſſ
ºf I. º: Hºg
- | 4
b the platten; ec handles which revolve on the screw d, and are used to draw
down the platten on the paper, &c. placed underneath; e is a square piece of
steel in which the screw works; the square piece slides in a hole of a similar
figure on the head of the press, (as shown by the dotted lines at f), and on the
top of it is a small cam g, operated upon by the lever h. The ordinary pressure
is given, as usual, by the screw; and the cam being subsequently brought down,
increases the force almost to infinity through a very small space, and, con-
sequently, by such a press, a person exerting only the usual force can print
effectually a larger surface. The other arrangements will be evident upon an
inspection of the drawing.
A very simple, and, at the same time, effectual, copying machine may be
made as follows: Take a roller of beech, or any hard wood, about 18 inches
long, and 1 inch in diameter, and having cut a longitudinal slit therein nearly
the whole length, insert in it and fasten very neatly with glue a slip of strong
cloth, about 14 inches wide, and 18 inches long; the remaining part of the
roller will serve as a handle, and may be cut with several faces to obtain a
firmer hold. To use this copying press, lay the sheet of paper on which the
letter is written upon the strip of cloth; on that place the thin copying paper,
and upon these lay a thick baize, or horse-hair pad; then roll the whole round
the roller, and grasping that part where the cloth is with the Jeft hand, turn the
roller round with the right, gradually increasing the grasp with the left; the
pressure becomes very great, and quite sufficient to transfer the letter to the
copying paper.
CORAL, and CoRAL FISHERy. The substance called coral was formerly
considered to be of vegetable origin, but it is now admitted to be of animal
origin, belonging to the order Zoophytes: by analysis it is found to consist
almost wholly of animal matter and carbonate of lime. The coral plants, (as









CORK. 401
they are termed) sometimes shoot out like trees without leaves in winter; they
often spread out a broad surface like a fan, and not uncommonly a large bundling
head like a faggot; sometimes they are found to resemble a plant, with leaves
and flowers, and often the antlers of a stag, with great exactness and regularity.
If, in our researches after the nature of these plants, we should be induced to
break off a branch of the coraline substance, and observe it carefully, we shall
perceive its whole surface, which is very rugged and irregular, covered with a
mucous fluid, and almost in every part studded with little jelly-like drops, .
which, when closely examined, will be found to be no other than insects of the
polypus kind. If a coraline plant be strictly examined whilst growing in the
sea, and the animals upon the surface be not disturbed, either by the agitation
of the waters or the touch of the observer, the little polypi will then be seen in
infinite numbers, each issuing from its cell, and, in some kinds, the head
covered with a little shell resembling an umbrella, the arms spread abroad in
order to seize its prey, while the hinder part still remains attached to its
habitation, whence it never wholly removes. By this time it is perceived that
the number of its inhabitants is infinitely greater than was at first suspected;
that they are all assiduously employed in the same pursuits; and that they
issue from their respective cells, and retire into them at pleasure. The true, or
red coral, was considered by Linnaeus as an isis, and arranged as such in the
Systema, though Linnaeus himself acknowledged to Mr. Ellis, the author of the
Natural History of Zoophytes, that the latter had more properly classed it with
the gorgonia, or sea-fan. The red coral grows in an exposed and somewhat
flattened form, with dichotomous branches, that lessen towards their extremities.
The flesh is of the colour of red lead, or inclining to vermilion, soft, slippery,
and full of minute vessels. The mouths are placed on the surface, and rise up
in a conical form, consisting of eight valves, just opening, whence proceed polypi
of a white colour, with eight claws, each of which has a double fibre at both
edges. The bone, or shell itself, divested of the flesh, is the true coral of the
shops, and which, in its natural state, is of a strong texture, and of a bright red
colour, with the outside marked with minute furrows, or irregular striations,
interspersed with a few slight depressions, corresponding with the situation of
the shells before the flesh was removed. The coral fishery is a very lucrative
employment. The time for fishing is from April to July; the places are the
Persian Gulf, the Red Sea, the coasts of Africa, towards the bastion of France,
the isles of Majorca and Corsica, and the coasts of Provence and Catalonia.
Spallanzini, in his Travels in the Two Sicilies, has particularly described the
coral fishery in the Strait of Messina. The instrument by which they force the
branches of coral from the rocks, is formed with two poles of wood, crossing
each other at right angles, and having a piece of net fastened on the under side
to their extremities. A large stone is fixed where the poles are crossed, that the
instrument may more readily sink to the bottom. A cord is strongly tied round
the middle of it, one end of which the fisherman holds in his hand, guiding by
it the net to those places where the coral is supposed to grow, and which is
enclosed in the pieces of the net, broken off and drawn up. The rocks which
produce the coral are situated almost in the middle of the Strait, at different
depths, from 350 to 650 feet. The bottom and caverns of the rocks are the
places from which they endeavour to bring up the coral in their nets, and it is
a constant observation, that every branch is perpendicular to the plane on
which it grows, without ever turning on one side. The coral fishermen have
divided the whole track in which they fish into ten parts. Every year they
fish in only one of these parts, and do not fish in it again till ten years are
elapsed. This interval of ten years they think necessary for the coral to acquire
its full growth in height and consistence. When they transgress this law they
find the coral smaller and of less consistence; and the intensity of the colour
is always in proportion to the number of years they have desisted from fishing.
CORK. The bark of a tree growing wild in the southern parts of Europe,
especially in Spain and Portugal. When the tree is about fifteen years of age,
it may be barked; and the operation may be repeated for several years, the
bark growing again, and its quality improving as the age of the tree increases.
402 CC) RN.
It is chiefly used for forming stoppers for bottles, and floats for fishermen's
netS.
CORN. A general name for the various kinds of grain which serve as food for
man or other animals; thus wheat, rye, barley, maize, &c., are comprehended
under the term corn. In England, however, it is usually understood to signify
wheat; in America, and most parts of the world, the term implies maize, or
Indian corn. Owing to adventitious or natural circumstances, corn is fre-
quently combined with a variety of impurities, denominated smut-ball, dust-
brand, pepper-brand, mildew, must, besides a portion that is decayed or
partially eaten by insects; there is also frequently a mixture of gravel, earth,
and different foreign substances, to a greater or less extent. To free corn from
these impurities, numerous machines have been designed, but their effec-
tiveness has proved so limited or partial, as to cause them to be very little
employed; and damaged or impure corn, in consequence, possesses a value
in the market far below what its intrinsic worth would be considered were there
known some simple and cheap process for separating effectually the good from
the bad. An apparatus for this purpose was, however, very recently patented,
which, in our opinion, is calculated to supply the desideratum in that
important branch of art, the experiments already made with it having proved
highly satisfactory. We make the following abstract from the specification
(leaving out the references to the drawing), which embraces other mechanism
and processes immediately connected with the subject under consideration.
Hebert's Patent Scouring, Washing, and Separating Machine. This apparatus
“is brought into use whenever the adventitious or impure matter cannot be
effectually removed by sifting or other dry operation. The grain to be washed
I deposit on a floor in the upper part of a building, and contiguous to a
hopper that is fixed to, and passes through a cavity in the floor. Near to this
hopper I also collect a heap of very coarse sharp sand (fragments of buhr
stones answer well), which has been previously well washed and sifted, so as to
detain only those particles which measure from a sixteenth to a thirtieth part
of an inch in diameter, and to free it from those which are either coarser or
finer. Into the said hopper I then throw a charge for the scouring cylinder
(situated underneath it on the next floor); the charge consisting of a mixture
of the grain and coarse sand, in the proportion of about five shovelsfull of
the grain to one of the sand in its wet state. The length of the scouring
cylinder should be proportioned to the magnitude of the operations intended to
be conducted by it; but its diameter should not be less than 30 or 36 inches,
in order that the pressure of the superincumbent portion upon the lower may
cause the sharp angles of the interposed coarse sand to scour off the impurities
adhering to the surfaces of the grain. A slow rotation of the cylinder for a
few minutes will in general suffice to complete this part of the process; the
state of which may at any time be ascertained by drawing out a sample of the
grain through a try-hole, made in one of the flat ends of the cylinder, and
provided with a stopper. When completed, the door in the cylinder is to be
unfastened, and the mixed materials are to be discharged into a large, flat,
rectangular sieve, suspended underneath it, and lying submerged in a large
body of water contained in a bath. This being done, the cylinder is to be
turned half way round upon its axis, so as to bring the open doorway upper-
most, and opposite to the short of the hopper above, in order to its being re-
charged as before; after which the door is to be refastened. From this time,
and at every subsequent charge until the work is completed, both the scouring
cylinder and the washing and separating bath operate together, the grain in
the sieve being agitated by the rotative action of the cylinder in the following
manner. On the revolving axis of the cylinder is fixed a pulley, which, by
means of an endless corder chain and two guide pulleys (employed to convert
the vertical into a horizontal motion), causes a fourth pulley to revolve in a
horizontal plane: on the upper side of the last mentioned pulley is a plate, having
an eccentric groove, in which a pin fixed to the centre of the bottom of the sieve
works; this arrangement, so far, causes the sieve to perform a circular motion
in the water; but the sieve is suspended from its four corners to two projecting
COTTON. 403
arms or levers, fastened to two horizontal spindles (acting as their fulcra), and
is, in consequence, made to incline alternately from side to side, in a constantly
varying plane, during each revolution of the eccentric plate before mentioned.
This compound motion produces a great agitation amongst the particles of corn
and sand, causing them to be quickly and thoroughly separated from each
other, and the corn to be well washed by the collision. The sand passes
through the meshes of the sieve, and is deposited at the bottom of the bath;
the bad corn, from its inferior specific gravity, rises to the surface of the water,
whence it is floated away by a gentle current over a partition or dam in the
bath, into a receptacle on the other side, whence it flows through a spout out
of the machine. The current is produced by the constant running into the
bath of a small stream of water from a pipe and cock at the opposite end of
the bath, and a constant level of water is preserved by its running over the
dam. The purified corn alone remaining in the sieve, is now to be dis-
charged thence; for this purpose, two levers fixed to the before-mentioned
spindles, and connected by a rod (to cause them to move parallel with each
other), are brought into operation; so that upon one of them being pulled, the
sieve is lifted out of the water and placed in an inclined position, by which the
contents are easily projected into a contiguous hopper, where the corn is
allowed to drain during the washing of the succeeding charge of grain, and
then it is conducted into the kiln to be dried. See KILN.
CORROSIVE SUBLIMATE. The chloride of mercury; also called the
oxymuriate of mercury.
COTTON. The down of the cotton tree or plant, of which naturalists
recognise ten varieties. Some of these are to be met with in the warmer
parts of Europe; but its cultivation to any extent is chiefly confined to
climates within the tropics. The generality of the West India species are
annuals, whilst those of Asia are perennial both in branch and root, and rise
in a straight line about eight feet high. The cotton down is contained within
pods, which, when arrived at maturity, open. The down envelopes a husk
called the gin, which contains the seeds of the plant; and the first operation
in rendering cotton fit for manufacturing purposes, consists in freeing the down
from these seeds. This is effected by first drying it in the sun until the seeds
become quite hard; and then operating upon it by a machine called a gin, of
which there are two kinds, the one called a roller gin and the other a saw gin.
The roller gin is represented in Fig. 1. It consists of two small fluted rollers
a b, about 1 inch in diameter, and 9 inches long, and generally made of
hard wood; they are put in motion by the treadle c acting upon cranks or
Fig. 1. Fig. 2.
pins in the face of the fly-wheel d. The labourer who drives the machine
places the cotton on a feeding board, and the cotton is drawn in between the
rollers, which being set too close to allow the seeds to pass between them, the
cotton falls down the inclined board e, and the seeds drop into the box f.
The saw gin is given in Fig. 2. a is a roller having a number of circular
saws b fixed upon it, with a washer of wood between each ; c is a grating


404 COTTON SPINNING.
through which a portion of the teeth of the saws project; d is a circular brush
driven by the wheel e on the axis of a, which works into a pinion on the axis
of d. The cotton being put into the hopper f, the teeth of the saws lay
hold of the wool and tear it through the grating, whilst the seeds are by that
means separated, and roll down the inclined plane of the grating, and finally
escape at the spout g; the cylindrical brush serves to clear the cotton from the
teeth of the saws, and throw it clear of the cylinder, in which state it is ready
to be packed for the market.
COTTON SPINNING ; the operation by which cotton-wool is formed into
yarn. The most ancient and simple method of forming filamentous substances
into a continuous thread was undoubtedly by the distaff and spindle, a method
still practised by the natives of India, and which appears to be known to every
nation removed one step from absolute barbarism, The first improvement upon
this simple contrivance was the spinning wheel, invented at a remote and un-
certain period; and by means of this machine, with some slight improve-
ments in its construction, the operation of spinning continued to be performed
in this country until the latter part of the last century, when an entirely new
system was introduced in the art, the process being no longer dependent upon
the skill and intelligence of the artisan, but every part of it being performed
by mechanical means, with a degree of accuracy and dispatch before unknown.
The new system spread with great rapidity, and quickly raised our cotton
manufactures, which were previously of small importance, to rank amongst the
principal ones of the country. From a paper in the Repertory of Arts, it
appears that so early as 1730 Mr. John Wyatt, of Birmingham, conceived the
idea of spinning by machinery, and that becoming associated with a foreigner
named Lewis Paul, a patent was taken out in the name of the latter in 1738.
In 1742 a mill was erected at Birmingham, which was turned by two asses. A
more successful result attended the exertions of Richard Hargreaves, a weaver
in Lancashire, who, in 1767, invented what is called the spinning jenny.
In 1769 R. Arkwright invented the method known by the name of water
spinning; and in 1779 Crompton combined the principles of jenny spinning
and water spinning into a system called mule spinning, and by one or other of
these three methods the operation is now performed.
We shall proceed to describe, as briefly as is consistent with perspicuity, each
of these methods, taking them in the order in which the inventions stand in
point of time; but first, we must note the method by which the cotton wool
(which arrives in this country very imperfectly cleaned from seeds, dust, &c.)
is freed from these impurities. This operation, which is called batting, is
performed by a machine called a batter, of which the annexed cut is a diagram.
ſº
fºy
- A.Y
(b) sº 2.
Ž
7:
The cotton is laid upon the endless web, or band, passing round the roilers a b,
and by this band, which is called the feeding cloth, it is carried to the rollers
c d, which deliver it upon the curved rack or grating e, whilst a scutch f
revolving rapidly upon its axis, strikes the cotton with its two edges and divides
it, and the gins, sand, &c. fall through the circular grating e, and down the
inclined grating i, at the same time a draft of air, created by the revolution of
the fan k, blows the cotton forward along the passage l into a box, from which

COTTON SPINNING. 405
it is from time to time removed, any remaining seeds falling from the cotton
through the grating m, (which forms the bottom of the passage l,) as the
cotton is blown along the passage.
We shall now proceed to give a verbal description of the process of jenny
spinning, unaccompanied by any representations of the machinery, which
being the same as that which, combined with some other machinery, is used
in mule spinning, will be described under that head. The process is as follows:
The cotton, after batting, is soaped, by being immersed in a strong solution of
soap; then pressed in a screw press, and afterwards stove-dried. It is then
carded by a carding machine, from which it passes in the form of rolls, about
the size of a candle, on to an endless band, from which it is lifted by children,
and carried to be roved. The roving is performed on a billy, usually containing
thirty-six spindles, driven by bands from a cylinder turned by hand. Upon
the side next the carding engine is a feeding cloth, upon which the rolls from
the carding engine are united so as to form a number of rolls equal to the
number of spindles in the billy. After a certain number of revolutions of the
rollers of the feeding cloth, the cloth is stopped, and the rolls being held fast
between two clasps of wood, the ends are attached to the spindles, that are
mounted on a movable carriage, which, as it recedes, stretches the rolls and reduces
them to the proper size of the roving. In returning the carriage, the rovings
are built upon the spindles in the form of cones, receiving at the same time
a slight twist; and when a sufficient quantity of roving is wound upon the
spindles, they are removed to the spinning jenny. The spinning jenny differs
from the roving billy in having the clasp boards attached to movable frames or
carriages, and the spindles stationary. The clasps, by the receding of the
carriage, reduce the rovings to the size for yarn, and during the return of the
carriage the yarn is built upon the spindles. Jenny yarn is now little used,
except for the weft of calicoes. Water spinning is the name given to Arkwright's
method of spinning, because in all the mills in which it was first adopted the
machinery was driven by water. The distinguishing feature of this method is
the means by which the rovings are gradually reduced in thickness to the size
of the intended yarn. In jenny spinning, we have already stated, this is
effected by nipping the rovings at one part between wooden clasps, and causing
the spindles to which the end of the rovings are attached to recede very
gradually; but in water spinning this is effected by passing the rovings between
the drawing rollers faster than it is taken in by the feed rollers; the fibres slide
one over the other, and the roving is reduced in thickness, or extended in
length, in proportion to the difference of the velocities of the feed rollers and
drawing rollers. The process of water spinning is conducted as follows:
After batting, the wool is carded by two machines, the first called the breaker,
and the second the finisher. The annexed diagram will give some idea of the
nature of the operation, and of the construction of the machine. The cotton
is carried by the feeding cloth a a to the feed rollers b b, which deliver it on to
the carding cylinder c. This cylinder is covered with slips of leather, stuck
full of bent wires, forming what are called cards, which are ranged parallel to

3 p -
4t)6 COTTON SPINNING,
the axis of the cylinder; the arched top d of the box in which the cylinder is
enclosed is likewise covered with similar cards, the teeth of which incline in an
opposite direction; as the cylinder slowly revolves, the cotton is repeatedly torn
from it by the top cards, from which it is recovered by the cylinder, until the
cotton at length reaches the doffer e, which is a cylinder with the cards ranged
round it in one continued spiral fillet, that strips the cotton wool from the
cylinder in a thin film, which is removed by a steel comb.f, worked by a crank
g; and by the comb it is thrown on to a smooth cylinder h, called the lapping
cylinder; this is surmounted by a light roller i, by which the film of wool is
pressed flat upon the cylinder, forming what is termed a tap. After a certain
number of layers are wound upon the lapping cylinder, which is called plying,
or doubling, the machine is stopped, and the lap broken off and removed to
the finisher, which has a carding cylinder, doffer, and comb, similar to the
breaker; but instead of the wool, as it comes from the comb, passing round a
lapping cylinder, it is drawn through a conical vessel by a pair of rollers, which
compress it, and deliver it in thin slivers or bands into tin cans; these, when full,
are removed to the draw frame, which is represented in the following diagram.
§ (WFTG)
ºrgºs
º: b TIF II
ſ º *|| || | º C.
º | | ||
The draw frame contains several heads of rollers, each head composed of a
pair of feeding rollers a a, and a pair of draw rollers b b : the upper roller in
each pair is covered with leather, or some other elastic substance, and the
lower pair is formed of metal, and fluted. The ends of the slivers con-
tained in the cans c c are passed through the leader d, and brought under the
rollers a a and b b. If, now, we suppose the rollers b b to travel four times as
fast as the feed rollers a a, or to have a draught of four, as it is termed, the
slivers will be drawn out to four times their original
length. The slivers are united by passing through
a conical ring, and conducted by a pair of rollers
ff, (which do not draw or extend the cotton,) into
another can g; and if we suppose four ends to be thus
united, the sliver will be of the same thickness as
the original sliver, but of four times the length. ”
This operation being repeated through several other
heads on the same frame, the fibres of the cotton
are laid nearly parallel, the sliver becomes more
uniform, and is then ready to be carried to the
roving frame, in which, besides being reduced, it
receives a slight degree of twist. Roving frames
have been variously constructed, but the form most
approved and in most general use at the present
day is what is termed the spindle and flyer roving
frame, represented by the annexed diagram. a a, b b, tº
are draw rollers, between which the sliver is con- kº.
ducted from the cam c, and reduced according to H.
the draught of the rollers; d d is the flyer fixed upon T
the top of the spindle e, which is put in motion by a Ç
band passing over the wheelf. The rollers deliver \º
the reduced sliver to the flyers on the top of the






COTTON SPINNING. 407
spindles, where it passes through an eye g, and thence proceeds down one of
the legs of the flyer (which is made tubular for that purpose,) to the bobbin h,
placed loosely on the spindle c, and supported on the rail. The tube of the
flyer running swiftly round the bobbin, lays the roving (which thus acquires a
twist) on the bobbin as fast as the rollers deliver it; and in order to cover the
surface of the bobbin with regularity, the rail i is made to ascend and descend
alternately with a slow motion. The bobbin, it will be observed, is dragged
round by the flyers, and but for the friction of the surface on which it rests,
would move as fast as the flyers; but in this case it would take up no roving,
for the quantity taken up will depend upon the difference between the speed
of the flyer and the bobbin. A slight ſº of friction is then necessary to
give the bobbin a slow motion, but as the bobbin becomes full, the weight
increases the friction, and consequently would retard the motion still further
if it were only dragged round by the flyer ; and as it is requisite that
the bobbin should always take up the same quantity of roving, its motion
is regulated so as to take up the roving exactly as fast as it is delivered from
the rollers. The mechanism by which this is accomplished varies in different
mills; the following is one of the most approved methods. Two conical barrels
are placed opposite each other, the large end of the one fronting the small end
of the other. One of these barrels moving uniformly turns the other barrel,
by means of an endless strap, which, by being shifted towards either extremity,
varies the speed of the other barrel. The belt or strap remains equally tight
in every part of the barrels, for the diameter of the one increases in exactly the
same proportion as that of the other diminishes. From the second barrel
motion is conveyed to pulleys k resting on the bearer or rail i, and having the
spindles passing through the centre of each ; the bobbins rest on those pulleys,
and are carried round with them. The rovings are next carried to the spinning
frame. The spinning frame is similar in its operation to the roving frame,
except that it has generally three sets of drawing rollers, and from the greater
strength which the thread has acquired, no machinery is requisite to regulate
its motion; it is therefore dragged round by the flyers. The bobbins, when
taken off the spindles filled with water twist for warps, are carried to be reeled.
The reel is composed of six rails, in front of which the bobbins are ranged on
pins, in a board extending the whole length of the reel. The dimensions of
the reel are such as that it requires exactly 13 yard to go round it; the thread
from the bobbins, after passing between several wires, to give a proper degree
of tension, is made fast to one of the rails, and the wheel set in motion. After
eighty revolutions (one lay) a bell or click strikes, the reel is stopped, and the
lays are tied with pieces of thread to keep them distinct. Seven lays form a
hank. When the hanks are completed they are taken off the reel, for which
purpose one of the rails is hinged, which permits it to be folded inward, and
the hank being slided to one end of the reel, the reel is lifted off its bearing,
and the hanks are taken off.
It now remains to describe the ope-
ration of mule spinning. The preparation
is similar to that of water spinning; but
previously to the rovings receiving their
last reduction on the spinning frame,
they undergo a process called stretching.
The stretching frame nearly resembling
the mule, except in being of larger
dimensions: we shall proceed to de-
scribe the latter, by means of the
annexed diagram. a represents a roving
placed in a frame behind the drawing
rollers c d e. After passing between
the rollers, the reduced roving goes on
to the spindle f which are like those of
the common jenny, and have neither bobbins nor flyers. The spindles are
placed in a reclining position, and supported on a carriage g. The machine

408 COTTON SPINNING.
being put in motion, the carriage recedes as fast as the rollers deliver the
rovings, the spindles at the same time revolving rapidly, giving sufficient twist
to the yard to bear stretching. After the rollers have delivered a certain
length (a yard, for example,) of yarn thus imperfectly twisted, they stop, but
the carriage continues to recede half a yard further, for example, and the
spindles continue to revolve. The yarn is thus stretched, and forms a fair and
even thread. In order to save time, the spindles move more rapidly during the
process of stretching. The mechanism by which this is effected is called
double speed. The yarn being sufficiently hard twisted, the machine disengages
itself from the other moving parts of the mule; the attendant then returns the
carriage home to the rollers. By this arrangement, comprising the advantages
both of the rollers and the spindles, the thread is stretched more gently and
equally, and a much finer quality of yarn can therefore be produced. This
excellent machine, which has superseded the jenny, and, to a considerable
extent, the water frame, and which has carried the cotton manufacture to a
perfection it could not otherwise have attained, was invented by Samuel Crompton,
a young weaver of respectable' character and moderate circumstances, living at
Hall-in-the-Wood, near Bolton, and was completed by him in 1779. Being of
a retiring and unambitious disposition he took out no patent, and only regretted
that public curiosity would not allow him “to enjoy his little invention to
himself in his garret,” and to earn by his own manual labour, undisturbed, the
fruits of his ingenuity and perseverance. The very superior quality of his
yarn, it is said, drew persons from all quarters, to ascertain the manner whereby
he produced it. He stated to Mr. Bannatyne, that, on the invention of his
machine, he obtained 14s. per lb. for the spinning and preparation of No. 40,
(i.e. yarn of forty hanks to the pound); that a short time after he got 25s.
per lb. for the spinning and preparation of No. 60; and that he then spun a
small quantity of No. 80, to show that it was not impossible, as was supposed,
to spin yarn of so fine a grist, and for the spinning and preparation of this he
got 42s. per lb. ' These prices were obtained by the unrivalled excellence of
the yarn; and it affords a criterion to estimate the value of the machine, when
it is found that the price of yarn, No. 100, is at the present day only from
2s. 3d. to 3s. per lb., including the cost of the raw material, which is from 10d.
to 1s. per lb., this surprising reduction having been effected chiefly by the powers
of the mule; and notwithstanding it was before supposed to be impossible to
spin 80 hanks to the pound, as many as 350 hanks to the pound have since
been spun, each hank measuring 840 yards, and forming together a thread 167
miles in length ! Although the principle of Crompton's machine was excellent,
it was rudely constructed; his rollers were of wood, and all the parts clumsy;
for Crompton was unused to tools, and knew but little of mechanics before he
attempted to put to practice the beautiful combinations he had conceived. His
first machine contained but 20 or 30 spindles. Subsequently, Stones, of Harwich,
a machinist, constructed a mule in a workmanlike manner, making the rollers
of metal, and applying clock-work to move them; the mule was thus adapted
for 100 to 130 spindles. Baker, of Bury, and Hargraves, of Toddington,
introduced some improvements. In 1790, Mr. Kelly, of Lanark mills, applied
water power to the mule, and shortly after Mr. Wright, of Manchester, con-
structed a double mule. By these successive additions the machine was made
capable of working with no less than 400 spindles. Since this period mules have
been so much increased in size and effectiveness, that there are many at work
in Manchester and elsewhere of 800 spindles each, and some of the prodigious
number of 1100 spindles each, or 2200 the pair, the pair being managed by
one spinner. Mr. Crompton having made no attempt to secure this important
invention, Parliament was memorialized on the subject, and a grant of 5000l.
was obtained free of all charges; and it is worthy of remark, that at this time
(1812), there were at work, on the principle of his invention, between four and
five millions of spindles' But the course of improvement has not yet stopped;
mules are now constructed which do not require the aid of a spinner, the
mechanism being so contrived as to roll the spindle carriage out and in at the
£roper speed, without a hand touching it; and the only manual labour employed
COTTON SPIN NING. 409
in these machines, (which are called self-acting mules,) is that of the children
who join the broken threads. The first machine of this nature was invented
by the ingenious Mr. W. Strutt, of Derby, son of Mr. Jedediah Strutt, the
partner of Arkwright. This appears to have been in the year 1790; and two
years afterwards, Mr. Kelly, of Lanark mills, invented another self- acting
mule, which is thus described by him in a letter to Mr. Kennedy, which we
annex, as it furnishes a very interesting detail of the progress of improvement.
“I first applied water power to the common mules in the year 1790; that is,
we drove the mules by water, but put them up (that is, the carriage or spindle
frame) in the common way, by applying the hand to the fly-wheel, and by º:
the wheels (or mules) right and left; the spinner was thereby enabled to spin
two mules in place of one. . . . . The mules at that time were generally
driven with ropes, made with cotton mill-waste, from a lying shaft in the middle
of the room, and over gallows-pulleys above the fly-wheels, on each side of the
room. That mode of driving was succeeded by belts, which were in every
respect much better, and better adapted to self-acting mules, &c. From the
above date I constantly had in view the self-acting mule, and trying to bring it
into use ; and having got it to do very well for coarse numbers, I took out the
patent in the summer of 1792. The object then was to spin with young
people, like the water twist. For that purpose it was necessary that the carriage
should be put up without the necessity of applying the hand to the fly-wheel.
At first we used them completely self-acting in all the motions, the fly continuing
to revolve, and after receiving the full quantity of twist, the spindles stood,
the guide or faller was turned down on the inside of the spindles, and the points
were cleared of the thread at the same instant, by the rising of a guide, or
inside faller (if it might be so called). When the outside guide wire, or faller,
was moved round, or turned down to a certain point on the inside of the spindles,
it then disengaged, or rather allowed a pulley, driven from the back of the
belt-pulley, to come into geer, or action, and which gave motion to the spindles,
and took in the carriages at the same time (similar to the way you assist the
large mules in putting up). But in the above self-acting mule, which performed
every motion, after the spindles were stopped it required about three turns of
the fly-wheel to move round the faller, and put in action the above-mentioned
pulley that took in the carriage, which was a great loss of time. . We therefore
set aside that part of the apparatus or machinery, and allowed the mule to
stop in the common way, on receiving the full º of twist; and the
instant it stopped, the boy or girl, without putting their hand to the fly-wheel,
just turned the guide or faller with the hand, which instantly set in motion the
spindles, and took in the carriage, the cop being shaped by an inclined plane,
or other contrivance. . . . . It may naturally be asked, Why were not the self-
acting mules continued in use? At first, you know, the mules were about 144
spindles in size, and when power was applied, the spinner worked two of such ;
but the size of mules rapidly increased to 300 spindles and upwards, and two
such wheels being considered a sufficient task for a man to manage, the idea of
saving, by spinning with boys and girls, was thus superseded.” So numerous
and diversified have been the successive improvements in this important branch
of art, that a very large volume might readily be filled with merely a selection
of the more ingenious; but our prescribed limits compel us to confine our
present notice to the most successful, and we believe the most perfect mechanism
for spinning hitherto brought into use, which is the self-acting mule, invented by
Mr. Roberts, of the firm of Sharp and Roberts, of Manchester. The following
description of the invention, extracted from the patentee's specification, we
copy from the London Journal of Arts and Sciences, Vol. VIII. Second Series.
* The nature of my said invention consists of an improvement or improve-
ments in the mechanism employed to render self-acting the machines com-
monly known by the names of mule, billy, jenny, jack-frame, stretching frame,
and all other machines of that class, whether used to rove, slub, or spin cotton,
or other fibrous substances, the particular object of which improvement or
improvements is to effect in a more complete manner than has hitherto been
done by self-acting machines of the kinds above mentioned, the regular winding
.# 1 () CO'I'TON SPINNING.
on of the yarn, or roving, upon the spindles, by regulating their rotatory
motions according to the gradually varying form and increasing diameter of
the cop. In Figs. 1 and 2, a a is a mule carriage in two parts, one on each
side of the headstock, the parts being firmly united by b b, a connecting bar of
iron, and c c, an iron frame; to this is bolted in front a frame of iron d, which,
at its upper part, is supported by e, a spur piece, bolted to the bar b and to the
frame d. On studs in the spur piece are ff two ratchet tension barrels; to one
of these is fastened g a cord,
which, after passing over a
notch in the spur piece e, is
wound round and fastened to
h a drum or barrel; this has
also attached to and coiled
round it i another cord, which
after passing over j a guide
pulley, and a notch in the
spur piece, is attached to the
other ratchet barrel. A shaft
k, on which is keyed the drum
h, has a pinion l working into
m the toothed quadrant, which
receives an alternating motion
on its centre, through an arc
of about 900, whilst the car-
riage runs out and in, that is
to say, at every stretch. In a
groove in the inner arm of the
quadrant is n a sliding nut -
moved by 0 a double threaded leading screw, on the lower end of which is
keyed p a mitre wheel, gearing with q another mitre wheel, the central stud of
which is opposite to the centre of the quadrant. Attached to the back of mitre
wheel q is r, a pulley, which is turned at intervals by s an endless strap passing
round it, and t a sliding pulley. A weighted lever u, called the governor lever,
is movable on a stud in the back part of the carriage frame, and forms the
upper jaw of a pair of pincers, the lower jaw being v a stud in the carriage
end. The lever u, when not intended to press upon the stud v, is carried by
an adjustable nut on the lower end of w, a rod connected with the arm of the
counter faller, and having free play through a hole in a side projection from the
arm of the lever. When, in winding on, the tension of the yarn brings the
faller wires to nearly the same level, the dropping of the arm of the counter
faller allows the lever u to descend till it pinches the endless strap s against the
stud, and drags it along as the carriage runs in, until the rise of the counter
faller arm again raises the lever and liberates the strap. The spindles are
banded in the ordinary way, and the drums are driven by a band, which, after
taking both the grooves in a, the driving pulley, is spliced, instead of passing
from the carriage to the twist pulley, as in common mules. The pulley a' is
keyed on y, an inclined shaft, the upper end of which turns in a swivel collar,
and the lower end or foot in an arm of a bell crank. During the process of
twisting and backing off, the shaft y receives motion through 1, a mitre wheel,
which is keyed near its lower extremity, and is driven by 2, another mitre wheel
fixed on 3, a shaft, on which is also keyed 4, a double grooved driving pulley,
receiving motion by an endless band from 5, the twist pulley above. This
pulley band passes under a carrier pulley, and over a double grooved carrier
pulley, under the driving pulley 4, again over pulley 7, and under pulley 4,
round 8, a sliding carrier pulley, under 9, a carrier pulley, and thence to the
twist pulley. The mitre wheel 1, comes occasionally into gear with 10, another
mitre wheel, keyed on 11, a shaft, upon which is also keyed 12, a spur wheel,
which gears into 13, another spur wheel, firmly connected to 14, a drum or
barrel, which is called the winding-on barrel. The diameters of wheels 12 and
13 should be made to give, as nearly as possible, the proper amount of iotation
Fig. 1.


CCTTON SPINNING, 41 I
to the spindles, according to their diameters and those of the warves, the final
adjustment being made in the diameter of the barrel 14, the whole being
adapted to give so much motion to the spindles as will cause them to wind on
the whole stretch at the first run in. There is a cord 15, one end of which is
, -
tied to the sliding nut n in the arm of the quadrant m, and the other made fast to
the barrel, 14, after having made several coils round it; and 16 is an opposing

412 COTTON SPINNING.
cord, also coiled round and fastened to the barrel 14, and after passing under
17, a carrier pulley, and over 18, another carrier pulley, it sustains 19, a coun-
terpoise, which causes the barrel 14 to take up the cord 15 as the carriage
recedes from the rollers. A lever 20, inclined downwards at both ends, is
mounted at its middle upon 21, a tumbler shaft, carrying 22, a fixed vertical
arm, which is connected by 23, a link with the side arm of the bell crank; 24 is
a stopping bar, movable on a stud in the vertical arm of the tumbler shaft, its
lower end passing through and abutting by a shoulder against the upper side of a
mortise hole in 25, a stopping piece, which is bolted to the frame c ; the stopping
bar is held against the upper side of the slot by 26, a spiral spring; 27 is a
latch on a stud in a projection from the frame c, which is pressed by 28, a spring
in the direction of a catch on one side of the lever 20; 29 is a radial weight,
movable on a stud in the framing, and carrying on a stud near its centre, 30 a
friction roller, under which the inner inclined arm of the lever 20 passes, and
raises the weight a little just before the carriage completes its run inwards; 31
a stud in the framing, which, by stopping the latch 27 in its motion inwards,
disengages the lever 20 at the instant the carriage has completed its run, which
allows the weight 29 to depress the inner arm, and so to throw into gear the
mitre wheels 1 and 2, preparatory to the recommencement of twisting; 32 is
another radial weight, similar to the weight 29, having a friction roller, under
which the outer arm of lever 20 comes to raise it, as the carriage reaches its
outward limit. When the process of backing off is completed, the mechanism
for putting up, or running the carriage in, is put into gear, and simultaneously
with it; and by the same, or any other convenient means, the stopping bar 24
is depressed, and the weight 32 depressing the lever 20, shifts the mitre wheel
1 from the wheel 2 into gear with the wheel 10. The diagram, Fig. 3, is
intended to show the arrange-
ment of the connecting wheels, Fig. 3.
the winding on barrel, and the
crooked lever, when the spin- =ºn
dles are driven by bands from
a roller, instead of drums,
which, as far as the present
improvement or improvements
in the mule, billy, jenny, jack
frame, or stretching frame, are r -
concerned, is almost the only
difference in the several ma-
chines enumerated; they all *
being machines of the same
class, that is, in which is performed at intervals the winding on of the stretches
of yarn or rovings, though used for different purposes, and distinguished by
different names. A spur wheel a is keyed on the coupling shaft which connects
the spindle band rollers on each side of the headstock; b is a radial arm cen-
tred on the same coupling shaft, and connected by c, a link, with d, the crooked
lever, which is acted upon by the radial weights and catches, as described
before; e a double grooved pulley, keyed on the same shaft with f, a spur
wheel; g a double grooved carrier pulley, round which and the pulley e the
twist pulley band is passed twice, as before explained; h the winding on drum,
keyed on the same shaft as i, a spur wheel; j a spur wheel carried by the
radial arm b, and gearing into wheel f whilst the twist is being given, and into
wheel i during the winding on. In the adaptation of the present improve-
ments to the mule, billy, jenny, jack frame, or stretching frame, according to
the diameter of the cop to be formed, or the length of stretch made in the several
machines, it may be requisite to vary the length of the grooved arm of the
quadrant. Whilst the carriage is running in, it turns by the band g, Fig 2, the
drum h, its shaft k, and the piaion l, which works into the quadrant m. , When
the quadrant begins to move, its grooved arm stands about 120 beyond the ver-
tical position from the rollers, and during its action it turns on its centre
inwards, through an arc of about 900. At the commencement of a set of cops,

COTTON SPINNING. 413
the stud in the nut n, to which the cord 15 is attached, is set opposite, or nearly
so, to the centre of the quadrant, in which position it suffers no change of place
by the motion of the quadrant. As the carriage recedes from the point of
attachment of cord 15, it causes the rotation of the winding on drum 14, round
which the cord is coiled, and the drum through the train of wheels 13, 12, 10,
and 1, that of the pulley ar, which, by the spindle drums, gives motion to the
spindles (see Fig. 1.) The rotation of the spindles during the first run-in of
the carriage, just suffices to wind on the stretch of yarn upon the bare spindles.
As the diameter of the cop increases by each succeeding layer, fewer revolutions
will be requisite to effect the winding on of the constant length; and, therefore,
the whole quantity of motion imparted to the spindles during a run-in must
undergo progressive diminution so long as the diameter of the cop is increasing,
which goes on until the bottom is formed. This decrease of motion in the
spindles is obtained by lessening the quantity of cord to be uncoiled from the
winding-on barrel; an effect which results from the advance of the nut n along
the arm of the quadrant, the amount of the effect being exactly commensurate
with this advance, as is apparent when the grooved arm of the quadrant, at the
end of the run-in, nearly coincides with the line of traction of the cord 15.
The motion which slides the nut along the quadrant arm is produced in this
way. During the process of backing off, the spiral coils of yarn are unwound
from the ends of the spindles, and the faller is depressed when the counter
faller by its weight rises, and takes up the uncoiled or slack yarn, and thus the
faller wires keep up the tension as the yarn is uncoiling. Whilst the carriage
is running in, the spindles, in winding on the stretch of yarn, take up by
degrees the coil yarn also ; and as this is effected, the faller wires are brought
to nearly the same level. At the first run-in, this approach of the faller wires
takes place only as the carriage comes up to the rollers. The power of winding
on increasing as the diameter of the cop enlarges in the subsequent stretches,
the coil yarn gets taken up before the carriage has run home; and when this
occurs, the descent of the counter faller allows the governor lever u to fall, and ,
to pinch the endless strap s against the stud v. With the motion of the carriage
the strap is dragged along, and turns the leading screw 0, which slides the nut n
towards the circumference of the quadrant. The strap continues to be dragged
until the retardation of the taking up, from the diminished velocity of the spin-
dles thus produced, permits the counter faller again to rise and relieve the strap
from the pinch of the lever. In this way the nut n is made to advance upon
the quadrant arm, in proportion as the expanding diameter of the cop accele-
rates the action of winding on, and a correspondent abatement in the whole
number of revolutions of the spindles is the result. As soon as the cop has
attained its full diameter, that is, when the bottom is formed, the winding on
power then remaining uniform, the governor lever is no longer made to act
º the strap, and, consequently, the nut n travels no farther from the centre
of the quadrant during the completion of the cop. Besides the adjustment of
the whole amount of winding on motion, each stretch is adjusted to the growing
diameter of the cop, which is effected by causing the point of attachment of
the drag cord 15 to advance progressively upon the rim of the barrel 14. The
grooved arm of the quadrant, by carrying the point of attachment of the cord 15,
after the first stretch through an arc of about 900 at each run-in, causes the
cord to be uncoiled from the barrel 14, by a ratio increasing as the carriage
recedes from the quadrant; and this variable rotation of the barrel is increased
by the successive shifts of the nut n from the centre of the quadrant, thus
adapting the rotation of the spindles to the winding-on powers of the cop,
through its various diameters from the base to the summit of the cone. Havin
now described my improved mechanism for adapting the rotation of the spindles
to the regular taking up of the yarn or roving, as the form and diameter of the
cop changes throughout the operation of winding on, I do hereby declare, that
my invention consists in the method or means to be employed for that purpose
hereinbefore described. The mechanism thus employed by me affects the
rotation of the spindle in two ways; first, rotatory motion is given to a drum
or barrel, which turns the spindles whilst the carriage is running in by uncoiling
3 G
414 CRAMP.
from it a portion of a cord, strap, or chain, attached to the drum, and having
its other extremity fastened at some point in a radial arm which describes an
arc, whilst the winding-on drum is receding from the point of attachment of
the cord in a right line. This compound motion adjusts the rotation of the
spindles to the varying power of taking up by the conical cop as the yarn or
roving is being coiled on its different diameters, during the winding on of each
stretch. Secondly, during the progress of the formation of a cop, the situation
of the point of attachment of the uncoiled end of the cord, strap, or chain, on
the radial arm, is changed progressively, as the increasing bulk of the cop
demands fewer revolutions of the spindles to take up the stretch, and, conse-
quently, there is a shorter length of the cord to be uncoiled from the barrel.”
We refer the reader to the articles SPINNING and WEAviNG for further infor-
mation on this important branch of art, as cotton is not the only fibrous matter
to which such mechanism is applicable. It is a remarkable circumstance in the
cotton manufacture, and highly honourable to British skill, that all its numerous
and varied operations are performed by machinery. Mr. Baines, in his valuable
History of the Cotton Manufacture, justly observes, “It is by iron fingers, teeth,
and wheels, moving with exhaustless energy and devouring speed, that the
cotton is opened, cleaned, spread, carded, drawn, roved, spun, wound, warped,
dressed, and woven. The various machines are proportioned to each other in
regard to their capability of work, and they are so placed in the mill as to allow
the material to be carried from stage to stage with the least possible loss of
time. All are moving at once, the operations chasing each other; and all
derive their motion from the mighty engine, which, firmly seated in the lower
part of the building, and constantly fed with water and fuel, toils through the
day with the strength of perhaps a hundred horses. Men, in the meanwhile,
have merely to attend on this wonderful series of mechanism, to supply it with
work, to oil its joints, and to check its slight and infrequent irregularities; each
workman performing, or rather superintending, as much work as could have
been done by two or three hundred men sixty years ago. At the approach of
darkness, the building is illuminated by jets of flame, whose brilliance mimics
the light of day, the produce of an invisible vapour generated on the spot.
When it is remembered that these inventions have been made within the last
seventy years, it must be acknowledged that the cotton mill presents the most
striking example of the dominion obtained by human science over the powers
of nature, of which modern times can boast.” - -
COULTER. A stout iron knife or blade fixed to the beam of ploughs, which
serves to cut out the furrows.
COUNTERBALANCE. A weight applied to balance the vibrating parts of
machinery upon their axes, so as to cause them to turn freely, and to require
little power to put them in motion; also a weight by which a lever acted upon
by an intermitting force is returned to its position, as in the case of the beam
of a single acting steam engine.
COUPLING BOX. A mode of permanently connecting two shafts: they
are variously constructed, the most common being simply a tube embracing the
end of each shaft, with a pin or bolt passed through each.
CRAB. A kind of small capstan, consisting of an upright shaft, having
several holes at the top, through which long bars or levers are thrust. The
name of crab is likewise given to a simple portable crane, on the wheel-and-
axle principle, and chiefly used for raising building materials to the tops of
houses, &c. There is a machine, likewise called a crab, that is used in launching
ships, or heaving them off or on to their ways or slips.
CRADLE is a name given to a supporting frame of timbers, which is placed
under the bottom of a ship, in order to conduct her steadily into the water
when she is to be launched, at which time it supports her weight while she
slides down the inclined plane or slip, which is for this purpose smeared with
soap. The bedsteads for wounded seamen are also called cradles; these, as
well as those used for rocking children, require no particular description.
CRAMP. A portable kind of iron press, chiefly designed and employed for
closely compressing the joints of frame-work. See Floor ING CRAMP.
CRAN E. 415
CRANE. A machine employed at wharfs, warehouses, &c. for raising and
lowering goods; it consists of a long projecting arm, called the jib, having a
pulley at the outer end, over which passes the rope or chain by which the goods
$
-*.
-º
&
*
†:
º
{
---
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are raised, the other end of the rope being wound round a barrel either attached
to the foot of the jib, or placed at any convenient distance from it. Various
modes have been resorted to for turning the chain barrel; on piers and jetties








416 CRANE.
it is frequently placed erect, and worked like a capstan: another method which
was formerly very common, but is now little used, was to place it horizontally,
and connect it with the axis of a large hollow drum, within which were placed
a number of men, who, by stepping upon battens nailed upon the interior
circumference parallel to the axis, caused the drum to revolve. But the inost
effective and best mode of employing the strength of men in working cranes
(in situations which will admit of its application), is that invented and patented
by Mr. Hardy; as in the preceding plan, the chain barrel is connected with a
large drum fixed upon a horizontal axis, but the steps upon which the labourers
tread are ranged upon the outside (instead of the inside) of the drum, radiating
like the floats of an undershot water-wheel, and the labourers continually step
upon that arm or step which is horizontal, so as always to act upon the longest
lever. One or more of these cranes were erected at the East India Warehouses,
and the principle has been since rendered familiar to one very numerous
portion of the public by the invention ascribed to Mr. Cubitt, of Ipswich,--
called the treadmill.
The preceding figure represents a side elevation of Mr. L. Wright's patent
crane, erected at the West India Docks, and which was the subject of much
acrimonious eontroversy amongst some of the scientific periodicals of the time.
a is the principal wheel, fixed to and revolving with the chain barrel b on the
axis c ; the periphery of the wheel c is made perfectly flat on both sides, for
the reception of the numerous small wheels d, alternately placed on the opposite
sides of the ring, with their axes fixed into it; these, which may be called
friction wheels, are solid, about an inch thick, and five inches in diameter—
they are turned smooth, and made bright in all parts; e e are two (of four)
levers, worked by a four-throw crankff turned by the winches g g; the levers
pass between guides at 0, and slide over rollers at p, which form the fulcrum of
the levers; and by the revolutions of the cranks the levers are successively
projected against the under sides of the small wheels d, from whence they are,
by the continued revolution of the cranks, again withdrawn, and again projected
under the next little wheel below the former, each wheel being raised by the
angular motion of the lever over which it rolls. It should be observed that only
one side or half of the machine is seen, the other side being a duplicate of it,
having two similar levers, large wheel, and smaller wheels, &c. The machine
(as delineated) is in gear; to put it out of gear a locking bar t is lifted, and
thrown into the position shown by the dotted lines; then the framing r which
carries the crank, inclined planes, and fly-wheel, and turns upon the centre s,
is thrown back, by which the axis of the crank moves in the arc of a circle
(shown by dots) to the position n. What mechanical advantage the inventor
expected to obtain by this singular construction, it is hard to say; the machine
is cumbersome and unsightly, has a complication of parts, in which the friction
far exceeds that of a well-made crane of the common construction, to which it
is also decidedly inferior in the circumstance of affording no means of altering
the power or velocity according to the weight to be raised. The method adopted
by the inventor for putting the machine in and out of gear is also very defective;
but if the crane offered any advantages in other respects, this latter defect
might be obviated.
In Mr. Revis's patent crane, which we are about to describe, the alternating
motion of a single lever is employed to producerotatory motion by means of a well-
known mechanical arrangement, instead of producing such motion by turning a
winch. The engraving on the succeeding page represents an elevation of this
machine. a is the alternating lever (shown as broken into two parts for want of
space), and having a counterbalance at a ; it is on the opposite side of the machine
to that represented, and its fulcrum being the axis of the toothed wheel b, which
gears into another toothed wheel c, motion is given to both wheels in opposite
directions. These two wheels are shown merely by two dotted circles, to avoid
confusion in the drawing. On the axis of the wheels b and c are placed tne
wheels d and e, which are not fixed to the axles, but turn loosely upon
them ; each of these wheels carry four palls or clicks, which fall into the
notches of two ratchet wheels f and g that are fixed to the axis on which d and
CRANE. 4 1 7
e turn loosely. The operation of the lever, therefore, which causes the two first
mentioned wheels b and c to revolve in opposite directions, produces precisely
the same effect upon the ratchet wheels fg. It will now be observed that
the ratchet teeth and palls of both wheels incline, in respect to each other, in
the same direction; and as the ratchets are turned round in opposite directions,
the palls in one wheel slip over the ratchet teeth, while in the other wheel the
palls catch into the ratchet; the latter is thereby locked to the toothed wheel,
which now operates upon the toothed wheel l on the working barrel, upon which
the rope or chain r is wound. During this process, the other wheel and ratchet
(which we will suppose to be d.f.) has no effect, from their not being connected;
F-— - - - - - - * * a
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but upon reversing the motion of the lever, these become fastened together,
while the former are simultaneously loosened; and as the wheel d revolves in
an opposite direction to e, the wheel l is turned round in the same direction as
previously, and the rope or chain on the barrel proceeds in an uniform course.
Having thus explained the manner in which the motion of the lever a is com-
municated to the other wheels b c, and thence to the rest of the machine,
it is obvious that the putting of the wheel b out of gear with the wheel c, will
stop the forward action of the crane; this is effected by means of the lever h,
which turns horizontally upon a fulcrum pin at i, and slides the axis in its
bearings, so that the wheels w and c are placed out of contact with each other.









4 || 8 CRANE,
This is done when it is intended to lower the rope or chain; but if a weight
or goods be appended to it, the friction band m m is made to press against the
periphery of the fly-wheel k by raising the lever n, which, having its fulcrum at
o, draws the friction band tightly over the fly-wheel, and the goods are thus
lowered with safety and expedition. But, for general purposes, the wheel and
pinion turned by a winch is superior to all other modes of working cranes, and
more particularly is it superior to any arrangement of reciprocating levers, as it
produces a smooth continuous circular motion, avoids the jerks and concussions
attending the latter, and saves a vast deal of friction, complexity, and
expense; accordingly, we find the wheel and pinion now generally adopted
almost to the exclusion of every other method. We have already stated that
the barrel is sometimes attached to the jib so as to turn with it. The annexed
engraving represents an excellent construction of a crane of this description,
several of which are erected upon the wharfs of the Regent's Canah. a is an
upright pillar of cast iron firmly fixed in a foundation of masonry; b a pin in
O
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the head of a, which supports the jib c, and forms the pivot round which it
turns; d d two struts, supporting the extremities of the jib, and the lower
ends resting on a collar e encircling the lower part of the pillar, which collar is
suspended from the jib by the iron rods ff; g is one of the side frames sup-
porting the barrel h; k a toothed wheel on the axis of the barrel, and turned
by a pinion, on the axis of which is fixed the winch l. The crane is turned
round upon its pivot by means of the winch m, which, by means of an inter-
mediate wheel and pinion, turns the pinion n, working in the wheel o, fixed to
the base of the pillar a. -
The following figure represents a modification of the wheel and axle, known
by the name of the “Chinese Crane,” which, for simplicity of construction
and immense power, far surpasses any other machine which is applied to pur-
poses for j this is adapted; and however its modest and unassuming appear-
ance may prevent its admission into the elegant companies of wheels and
pinions, which we see associated together in this age of mechanical combination,
there can be little doubt that it will eventually work its way into notice by its
own merits, to the displacement of some of those complicated arrangements of
wood, iron, and brass, which, in some cases, seem to be erected for no other
purpose than for employing a horse to do the work of a man. The construction

CRANK. 419
of this machine will be readily under-
stood by reference to the figure. a b
is a windlass, which is worked by a
winch or handle c d. It will be seen that
the windlass a b partakes of two diame-
ters, that part from a to e being larger
than the remaining part e b : the cord g
is wound round the part a e of the wind-
lass, and is passed under the movable
pulley h i, and carried over the part
e b of the windlass, on the opposite side
to that from which it descended at a e :
the weight to be raised is suspended from
the pulley h i. Now if a power be applied
at d, and the windlass be caused to make
one revolution, a portion of the cord g
equal to the circumference of the part
a e of the windlass, will have been wound on to the windlass; but the part e b
of the windlass has also made one revolution, consequently a portion of the
cord, equal to the circumference of e b, has descended, so that after one revo-
lution the cord will have been shortened a quantity equal to the difference
between the larger and smaller barrel of the windlass; but as this difference
has been divided between the two parts of the cord g and k, it follows that the
weight has been raised through a space equal to only half the difference of the
circumferences a e and e b. But as circles are to each other as their radii, the
following simple rule may be deduced for calculating the power of these
machines; as c d, the radius of the winch, is to half the difference of the radii
of the parts of the windlass a e and e b, so is the weight w to the power which
is necessary to produce an equilibrium. For example, put c d-18, the radius
a e=6, and the radius e b=3; and suspend a weight of 108 lbs. from h : ; we
then have 6–3-2=1}, and as 18: 13:: 108: 9; consequently a power of 9
applied at the point d would be equivalent to a weight of 108 lbs. acting upon
the pulley h i. . This subject may perhaps be better understood by referring to
the annexed diagram, where a e represents the
radius of the larger part of the windlass, and b
the smaller radius, e d being the radius of the
winch; and we may suppose d a to represent a
lever, whose fulcrum is e ; and as each of the
ropes g k bear equal parts of the weight of 108 lbs.
we represent the whole weight by two distinct
weights g and k acting upon the points b and a
of the lever d a , and if we retain the propor-
tions de=18, a e= 16, and b e=3, we have a
weight k on one side of the fulcrum, at the dis-
tance of b, whose quantity is 54; and we have a
". of 54 acting on the opposite side of the fulcrum, at the distance of 3.
ow it will easily be seen from the principles of the lever, that g will sustain a
quantity equal to 3 k, consequently there will remain a weight of 27 acting
at a, to be kept in equilibrio by a force applied at d, but e d is 3 times e a,
therefore a power equal to 9 applied at d would balance a weight of 27 acting
at a ; which is precisely the same result as was obtained by the rule before laid
down, -
CRANK. A short arm or lever fixed to a shaft in any machine, and set in
motion by a connecting rod proceeding from some other part of the machine,
which has a reciprocating motion to and fro. To obtain a continuous rotatory
motion of the crank and shaft it is necessary to fix upon the shaft a fly-wheel
of considerably larger radius than the crank,-for when the connecting rod lies
in the same direction or right line as the crank, and no longer forms any angle
with it, it can have no tendency to move the crank to either side; but the heavy
fly-wheel, which, from its greater radius, has travelled much faster than the


420 CRANK.
crank, has acquired a considerable momentum, which urges round the crank
when the connecting rod has ceased to impel it, or carries the crank past the
dead points, as it is called. Although this means of obtaining a rotatory
motion had long been in practice in various machines, as in the turning-lathe,
and knife-grinder's wheel, yet it is a singular fact that a considerable time
elapsed after the invention of the steam engine ere the same simple and effective
method was employed to obtain a rotatory movement from the reciprocating
action of the engine beam, whilst several schemes, exhibiting much contrivance
and ingenuity, but which were inadequate to the object in view, were from time
to time proposed. By the addition of the crank and fly-wheel to the steam
engine, the latter, which before was chiefly used for pumping water, has become
generally applicable as a prime mover of machinery, and its utility has, in con-
sequence, been augmented a thousand fold. But the utility of the crank and
fly-wheel, as applicable to a steam engine, consists not merely in converting
rectilinear into circular motion, but also in gradually destroying the momentum
of the piston, and bringing it gently to a state of rest at the end of each stroke.
It is a law of nature that all bodies have a natural tendency to preserve their
state of motion or of rest, until opposed by some external force. This property
of matter occasions a great loss of power in the steam engine, where a massive
beam, with all its appendages, have to be reversed at each stroke of the engine;
and were it suddenly stopped and reversed when at its greatest velocity, the
shock would be so great as speedily to destroy the machinery. The loss of
power employed in overcoming the vis inertia of the beam cannot be avoided,
but the shock at the reversal of the motion is prevented by means of the crank,
in a manner which will be best explained by the diagram in the margin. Let
a b represent the crank of a steam engine, equal to half
the length of the stroke, or half d.f. and let d c a cf re-
present the semicircle through which the crank travels
whilst the piston performs a stroke, or moves through
the space d.f. Now, when the crank is in its present
position, the piston is at its greatest speed, and travels
with nearly the same velocity as the crank, moving
through the space b g whilst the crank passes from a to c.
But when the crank moves through the next portion of
its revolution c d, equal to the former portion a c, the
piston only moves through a space equal to g d in the
same time as it before moved through the space b g,
which is nearly double g d. hence it is seen that the
crank, by diminishing the speed, is admirably adapted for
preventing the shock which would be experienced from
too sudden a reversal of the motion. A want of a
thorough comprehension of the mode in which the fly-wheel and crank operate,
has been the origin of many attempts to supersede them. Of these we shall
only notice the following, which is the invention of Mr. J. Apsey.
At Fig. 1, page 421, is an elevation of the apparatus; a a is a strong elliptical
frame of cast iron, having fixed on each side a toothed rack b c. This frame is sup-
posed to be immediately connected to the piston rod of a steam engine or other
rectilineal moving force, the motion of which causes the toothed wheels d and
e (the wheel c is behind d, as is shown in the edge view of them at Fig. 2,) to
revolve on the axis i, which axis communicates its motion and force to whatever
machinery may be connected to it, f g are two guide bars, and hj are two
guide rings or annular plates, in front of the wheels d and e, which serve to
keep their respective parts in their proper places. It will be observed that the
frame a a is represented at the lowest point of its descent during such descent
it turns round the wheel d by means of the rack g, and at the same time causes
a revolution of the axis; by the ascent of the frame the wheel d revolves the
contrary way, but it then runs freely upon the axis, so as to have no influence
upon it; during the same time the opposite wheel e becomes locked to the axis;
and by means of the rack causes the axis to continue revolving in the direction
given to it by the previous operation of the wheel d, as will be best understood

CRANK. 421
by an explanation of Fig. 2, which exhibits the toothed wheels and axis distinct
from the frame and side racks. To each of the wheels d and e are fixed the
guide rings hj, and a clutch box k l, which turn with the wheels on a smooth
part of the axis, as shown at i in the separate Fig. 3. These wheels are
alternately connected to the axis, to give it motion, by means of the clutches
op, which have merely a sliding motion along, the axis, and are constantly
pressed against the boxes k l by means of helical springs q r wound upon the
axis, and confined in a case, as represented in the figure. The clutches op have
grooves made in them, as shown by the end views of them given in the separate
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figure o p, through which the stuts st, Fig. 3, slide, and secure them to turn
round with the axis. As the action of the apparatus may not be quite clear to
some of our readers by the foregoing, we will just repeat that the raising of the
elliptical frame containing the side racks, causes the wheel e to operate upon
the axis by its becoming locked to it by the agency of the clutch p, but on the
motion of the frame being reversed, by the reciprocating action of the piston rod,
or other rectilineal moving force, the wheel e is released from the axis, and the
other wheel d becomes locked to it by the agency of the clutch o, which carries
the axis round in the direction previously given to it, and by the repetition of the
alternations of the frame, the axis is caused to revolve continually in the same
direction. Motion is often required to be communicated to machinery at a
distance from the first mover, and this is usually effected by a metallic shaft,
which, if the distance between the machinery and the first mover be great,
must be made of considerable thickness, to prevent its being twisted to pieces
by the power applied, or else by chains, straps, or ropes, which, to prevent their
slipping on the drums or pulleys over which they pass, causes considerable
impediment to the motion by friction. These are inconveniences which cannot





3 H
422 }{RAY ON.
in all cases be avoided; but under some circumstances the following method of
transmitting motion through the medium of three rods and two triple cranks,
connecting the machinery with the first mover, might be introduced with
considerable advantage. The apparatus is represented with the axes of motion
laced horizontally by Fig. 1, and with the axes placed vertically by Fig. 2.
The same letters represent similar parts in both figures. It will be perceived
that the motion may be in the direction shown by the arrows, or the contrary;
and hence it may be reversed at pleasure. The triple crank a be, to be
put in rotation by any first mover, is connected by three rods to a similar
Fig. 1.
Fig. 2.
*E=E. U--- ... Tº “ --
*=T =T_.
[H & Hº
crank a b c of equal dimensions; and as the cranks project from the axes at
equal distances, there will always be one of them in a position to produce a
pulling action, and hence there will be no necessity for having the conducting
rods stronger than what may be sufficient to sustain, by tension, the resistance
of the machine to be put in motion, and thus the expense of transmitting
motion by this method to a considerable distance will be very small. The
motion, too, will be perfectly uniform ; for as the leverage of the crank a, for
instance, diminishes by its rotation, that of the corresponding crank a will be
equally diniinished; so that whatever motion is produced by the first mover
will be faithfully transferred to the machinery.
CRAPE. A light kind of stuff, somewhat like gauze, much used in mourn-
ing. It is made of raw silk, jammed and twisted in the mill, and woven without
crossing. Crapes are either crisped or smooth; the first double, expressing
a closer mourning; the latter single, used for denoting a less portion of grief.
The silk destined for the first is more twisted than that for the second; it being
the greater or less degree of twisting, especially of the warp, which produces
the crisping given to it: when taken out of the loom, it is steeped in clear
water, and rubbed with a piece of wax for that purpose. Crapes are all dyed
T3. W. *...
CRAYON is a general name given to various mineral and vegetable sub-
stances used in designing or painting in pastil, whether they have been beaten
and reduced to a paste, or are used in their primitive consistence, after sawing
or cutting them into long narrow slips. In this last manner red crayons, are
made from red chalk; white, from white chalk; black, from charcoal and black
lead. Crayons of all other colours are compositions of earths reduced to paste.
The tempering of crayons is found to be an operation of great nicety, to
avoid their being so hard as to impart an insufficient supply of colour; or, on
A

CRUCIBLE, 423
the contrary, so soft as to crumble away, and to be little better than a powder
upon the paper. A variety of slightly glutinous fluids have been proposed to
give them the due degree of coherence; but the strength and the kind of fluid
used requires to be varied according to the nature of the colour to be employed.
The English manufacturers employ a variety of substances for this purpose;
among which may be mentioned ale-wort, rendered glutinous by boiling, and
gum tragacanth. It is obvious that the marks made upon paper by such com-
positions as we have naentioned, can be but slightly attached to the paper, and
that they are extremely liable to be injured or defaced. Various means have
been resorted to for fixing them in such a manner, that, without having their
tints injured, they may be enabled to bear rubbing. When the picture is made
on unsized paper, Cathery recommends the back to be brushed over with a size
made of half an ounce of isinglass, and two drachms of powdered alum, boiled
for a quarter of an hour in a quart of water, and strained. This size, used
milk-warm, penetrates the paper, and effectually fixes the picture. He also
recommends another way, which is applicable to large drawings done on sized
paper; it consists in sponging with the glutinous fluid a piece of unsized or
blotting paper, of the same size as the picture. This wetted paper being laid flat
upon a table, the face of the picture is pressed upon it in every part. The
chalk thus becoming wet with size adheres to the original surface, and, by
taking care wholly to avoid the smallest sidewise motion whilst the two surfaces
are in contact, the colours are not in the least daubed, nor is the minute quan-
tity of colour transferred to the blotting paper any injury to the piece. Sebas-
tian Grandi, an Italian artist, communicated to the Society of Arts a process
for preparing crayons, which are stated to be of a quality greatly superior to
those commonly or previously in use, being fixed so as to prevent their being
rubbed off the paper when used, and are applicable alike to water or oil
paintings. These crayons are made of bone-ash powder, mixed with sper-
maceti, adding thereto the colouring matters. The proper proportion is three
ounces of spermaceti to one pound of the powder. The spermaceti to be first
dissolved in a pint of boiling water, then the white bone-ash added, and the
whole to be ground well together with as much of the colouring matter as may
be necessary for the shade of colour wanted. They are then to be rolled up in
their proper form, and gradually dried upon a board.
CREAM. The oily part of milk which rises to the surface of that liquid,
mixed with a little curd and serum. When churned, butter is obtained. Heat
separates the oily part, but injures its flavour.
CROWN SAW. A species of circular saw formed by cutting the teeth
round the edge of a cylinder.
CRUCIBLE. A pot in common use for a variety of chemical purposes. It
is generally made of clay, and is designed to withstand a strong heat. The
best crucibles for this purpose are the Hessian crucibles, composed, according to
Pott, of a mixture of very refractory clay with sand. The vessels are not
turned upon a potter's wheel, but the earth is kneaded into a very stiff mass,
and the form given by ramming it in an iron mould. A composition con-
sisting of two parts of Stourbridge clay, and one part of the hardest coke, well
ground and tempered together, has been employed with excellent results by
Mr. Anstey, of Somers Town. The following description of his process is an
extract from his account published in the Transactions of the Society of
Arts :- -
“Take two parts of fine ground raw Stourbridge clay, and one part of the
hardest gas coke, previously pulverized, and sifted through a sieve of one-
eighth of an inch mesh. . Mix the ingredients together with the proper quan-
tity of water, and tread the mass well (if the coke is ground fine the pots are
very apt to crack). The pot is moulded by hand on a wooden block, as shown
in the engraving in the next page, in which a is the bench; b b two uprights
supporting a cross-board c; d the wooden block on which the pots are moulded,
supported on a spindle e which turns in a hole in the bench; fa gauge to regulate
the thickness of the melting pot, as shown in the dotted lines; g a cap of linen
or cotton, placed wet on the core before the clay is put on—its use is to prevent
424 CUPEL.
the clay from sticking partially to the core while it is taking off; the cap adheres
to the pot only while wet, and may be renewed without trouble or hazard (to
the pot) when dry; h a wooden bat to assist in moulding the pot; when
moulded, they are carefully dried at a gentle heat. A pot dried as above, when
wanted for use, is first warmed by the fire-side, and is then laid in the furnace
with the mouth downwards (the red cokes being previously damped with cold
ones in order to lessen the heat); more coke is then thrown in till the pot is
covered, and it is then brought up gradually to a red heat. The pot is then
turned and fixed in a proper position in the furnace, without being allowed to
cool, and is then charged with cold iron, so that the metal, when melted, shall
have its surface a little below the mouth of the pot. The iron is melted in
about an hour and a half, and no flux or addition of any kind is made use of.
A pot will last for fourteen or even eighteen successive meltings, provided it is
not allowed to cool in the intervals; but if it cools, it probably cracks. These
pots will bear a greater heat than others without softening, and will, conse-
quently, deliver the metal in a more fluid state than the best Birmingham pots
will.” Crucibles are also sometimes made of porcelain, plumbago, iron, silver,
and platina.
CRYSTALLIZATION. That process of nature by which the particles of
bodies are arranged systematically in passing from a liquid to a solid state. The
phenomena of crystallization have much engaged the attention of modern
chemists, with a view to determine exactly the different figures assumed by
salts in crystallizing; but it does not yet appear that any certain rule can be
laid down in these cases, as these figures may be varied by the slightest circum-
stances, so that the same salt frequently assumes various figures, and very
different substances sometimes present themselves under absolutely the same
form. The most diligent observer of the phenomena of crystallization, and
who has been most successful in deducing a plausible theory from these obser-
vations, is M. Haüy ; to whose work, on the Theory and Structure of Crystals,
we would refer the reader who is desirous of obtaining the best information on
the subject.
CUCURBIT. A chemical vessel commonly called a body, made of earth or
glass, in the shape of a gourd, and therefore called a cucurbit. It is used in
place of a still for distillation.
CUPEL. A shallow earthen vessel used in that part of the process of assay-
ing termed cupellation. It is made of the phosphate of lime, or the residue of
burnt bones, rammed into a mould, which gives it its figure.

CYDER. 42.5
CUPELLATION. A process in assaying for freeing gold, silver, and pla-
tina, from alloys of other metals. It is performed as follows:—the precious
metal is put together with a due proportion of lead into a cupel, and the fusion
is effected by exposing them to a considerable heat in a muffle or small earthen
oven fixed in the midst of a furnace. The lead continually vitrifies or becomes
converted into a glassy cakx, which dissolves all the imperfect metals. This
fluid glass, with all its contents, soaks into the cupel, and leaves the precious
metal in a state of purity. During the cupellation, the scoriae running down
on all sides of the metallic mass produce an appearance called circulation, by
which the operator judges whether the process is going on well. When the
metal is nearly pure, certain prismatic colours flash suddenly across the surface
of the globule, which soon afterwards appears very brilliant and clean ; this is
called brightening, and shows that the operation is ended. After gold has
passed the cupel, it may still contain either of the other perfect metals, platina
and silver. The former is seldom suspected; the latter is separated by the
operation called quartation and parting.
CUPOLA, in Architecture, an hemispherical vault: this term is also applied
to the furnaces used for melting iron. See FoundRY.,
CURRYING is the art of preparing leather after it has been tanned, with
oil, tallow, and other matters calculated to give it pliability or suppleness, and
durability. See LEATHER.
CUTLERY is a general term applied to table knives, forks, scissors, pocket
knifes, razors, lancets, swords, and to a great variety of the more delicate kinds
of cutting instruments; it is distinguished from edge tools by the katter applying
to the coarser kinds of cutting instruments employed by artificers and
mechanics, such as axes, adzes, chisels, gouges, gravers, &c.; nevertheless, in
some of these it is necessary to the skilful operator to have the utmost pre-
cision of form and finish given to their cutting edges.
CYCLOGRAPH. An instrument used for describing arcs of circles in eases
where compasses cannot be employed. The most simple cyclograph is that
commonly used by artificers in describing arches for the tops of doors and
windows, which consists of two rods connected together at such an angle that
the apex may touch the highest point of the curve, whilst the sides of the rods
are in contact with points fixed in the extremities of the curve, and by turning
the instrument round, keeping the two legs in contact with the points at the
extremities of the curve, a tracing point in the apex will describe the required
arc. An improved instrument on this principle, invented by Mr. Rotch, is
described in the Transactions of the Society of Arts.
CYCLOID. That curve which is described by a point in the circumference
of a circle, during the revolution of the circle over a plane.
CYDER. A fermented beverage prepared from the juice of apples. Large
quantities of this liquor are made annually in England; that made in Here-
fordshire and Devonshire is generally accounted superior to any other. The
best practical directions on the art of preparing this liquor that have been
given to the public, are those of Messrs. Marshall, Crocker, and Knight, from
which chiefly the following account is compiled. The process may be divided
into three distinct parts. 1st. Preparing the fruit. 2d. Grinding and expressing
the juice. And 3d. Fermenting and bottling.
1st. In preparing the fruit care must be taken both as to its peculiar quality
and its stage of ripeness. Mr. Marshall is of opinion that the fruit should not be
gathered until fully ripe, which is when they begin to fall from the trees; but
as apples ripen very unequally on the same tree, he recommends that the trees
should first be gone over with a hook when the fruit begins to fall naturally,
and that they should be finally cleared with poles when all is ripened, or the
winter likely to set in. When the fruit has been gathered, it is usual to lay
them in heaps to sweat, but this appears to be only useful for such fruit as is
not perfectly ripe.
2d. Grinding and Pressing. The grinding is usually performed in a mill
nearly resembling a tanner's mill for grinding bark, and consists of a millstone
from 24 to 4} feet in diameter, from 9 to 10 inches in thickness, and 1 to 2 tons'
426 - DAIRY.
weight, and running on its edge in a circular stone trough. The bottom of the
trough in which the stone runs is somewhat wider than the stone itself; the
inner side of the groove rises perpendicularly, but the outer side is bevelled in
such a manner as to make the trough 6 or 8 inches wider at top than at
bottom. The runner or millstone turns upon a long shaft or axle passing
through its centre; the inner end of the shaft rests upon a pivot in the centre
of the mill bed, and the outer end extends beyond the circular trough, and is
there connected with a spring bar, to which a horse is attached. After the fruit
is ground it generally remains some time before it is pressed, to allow the rind
and seeds to communicate their virtues to the liquor: from twelve to sixteen
hours is sufficient for this purpose. In order to press the fruit, or pommage, as
it is now called, it is folded up in pieces of hair cloth, or placed between layers
of clean sweet straw or reed. The bed of the press, which is about 5 feet
square, should be made entirely of wood or stone, the practice of covering it
with lead being extremely pernicious. It has a channel cut a few inches within
its outer edges to catch the liquor as it is expressed, having under it a stone
trough or wooden vessel to receive it. The press is worked by levers of different
lengths, first a short one, then a longer one, both worked by hand, and lastly a
bar 8 or 9 feet long, worked by a capstan or windlass.
3d. Fermentation. The common practice is to have the liquor tunned imme-
diately, and to fill them quite full, but it is more proper to leave a small space to
be filled up afterwards. No ferment is added, as in malt liquors, but Mr. Marshall
thinks it would be desirable to do so, as it would more speedily determine the
fermentation, which at present is very precarious as to the time of its com-
mencement and its duration. The process of fermentation is variously conducted
by different cyder growers, some endeavouring to promote it in a spacious open
vat, whilst others endeavour to repress it by enclosing the liquor in hogsheads,
and excluding the air. After remaining a certain time in the fermenting
vessel, it is racked off from the leys and put into a fresh cask. A fresh fer-
mentation usually commences after racking, and if it becomes violent a fresh
racking is necessary to check it; but if only a small degree of fermentation
takes place, termed fretting, the liquor is suffered to remain in the same cask.
Mr. Crocker says, when the fermentation ceases, and the liquor appears toler-
ably clear to the eye, the pure part should be racked off into open vessels,
º placed in a cool situation for a day or two, after which it may be again
barrelled, and placed in some moderately cool situation for the winter.
D.
DAIRY is the art of manufacturing various kinds of food from milk; the
term dairy is likewise applied to the building where those operations are per-
formed. The great variety of business in a well-conducted dairy requiring
the most minute and assiduous attention, may be conceived by just stating the
principal heads; namely, the proper choice, food, and management of cows;
the mode of milking, according to the variation of circumstances; the manage-
ment of the milk and cream preparatory to the making of butter; the processes
of making butter according to the mechanism used for that purpose; the manner
of making the various kinds of cheese; the vatting, pressing, and salting the
same, &c. These important subjects, which scarcely fall within the plan of this
work, are most ably treated, in all their interesting details, in the Oxford Ency-
clopaedia, from which valuable publication we extract the following observations
on the proper position, structure, and arrangement, of a dairy and its utensils.
As respects the dairy-house, the author observes, “It is a matter of consider-
able importance that buildings of this description should be placed in a proper
situation, with respect to the other parts of the farm; this will save both
expense and labour, as well as promote convenience. Another principal object
in choosing a situation for the dairy is a proper degree of temperature for
carrying on the business which is to be conducted in it. To accomplish this,
the following are the chief objects to be aimed at. The dairy buildings should
DAIRY. 427
be situate sufficiently near the sheds or cow standings, that the milk may be
readily conveyed to them, the form being such as to combine well with the
nature of the other erections. The door or entrance into the room destined for
the milk should be made through that of the scalding room, which should have
the copper for heating water and other purposes, placed in a shed without it,
that the heat may be kept at as great a distance as possible from the milk, a cock
being fixed in the bottom of it for conveying the heated water through a trough
or pipe across the scalding room, in which another cock should be fixed for the
convenience of washing smaller utensils, passing the wall into the milk-leads,
pans, trays, or coolers, that whenever they are required to be scalded the
boiling water may at once pass through the whole range of them, or be de-
tained at pleasure in any one of them, so as to effect the business in the most
complete and perfect manner, being afterwards taken off by a suitable drain
made for the purpose. The passage of the water through the wall of the dairy
should be in a trough of sufficient dimensions to admit the discharging of a pail
full of milk into it with perfect safety, having a hair sieve so placed in it as that
the whole of the milk of the cows may be made to pass through it into the
necessary trays or coolers in which it is to stand, as by this simple contrivance
the necessity of dirty men or boys entering the dairy-house is wholly prevented.
There should be likewise a trough, pipe, or some other similar contrivance, for
the purpose of conveying the waste milk, whey, &c., from the dairy-house to
the cisterns for containing the wash for the pigs, &c. Several plans for regu-
lating the temperature of the dairy have been proposed by different persons.
It may be accomplished in various ways, as by having double walls and roofs,
or by hollow walls, or by the walls having a vacuity left of eight or ten inches
in width between the lath and plaster. A spring or fountain rising in the
centre of the principal apartment, when it can be procured, will be a most
valuable convenience. It is obvious that the nature and number of these
buildings on any farm must depend on the kind of dairy business proposed to
be carried on, whether milk, or butter, or cheese; and the size is always regu-
lated by the number of cows. The dimensions usually adopted in Glouces-
tershire are 20 feet by 16 for forty cows; and 40 feet by 30 for one hundred
cows. It is well known that without a suitable place for preserving the milk
and performing the various operations, the dairy business cannot proceed with
any prospect of advantage. To preserve an equable temperature, a northern
aspect has been suggested as the most proper. These apartments should be dry,
and to render them clean and sweet at all periods without much trouble, their
situation should be in the immediate neighbourhood of a spring or clear
rivulet. The roof and walls should also be defended from the action of the
sun's rays by shady trees, buildings, &c. For the milk dairy two good rooms
are all that are necessary; namely, one for scalding, cleaning, and airing the
utensils, and the other for the reception of the milk. For a butter dairy three
apartments will be required; one for holding, washing, scalding, and airing the
utensils; one for keeping the milk; and one for churning the butter. Four
apartments are necessary to a well-constructed cheese dairy; namely, one for
the reception of the milk: another for the scalding and pressing of the cheese;
a third, where it is salted; and a fourth, called the cheese-loft, in which the
cheeses are deposited.” As respects the dairy utensils, our writer states, that
“the only proper materials for making the vessels and implements belonging to
a dairy are wood, porcelain, glass, and slate; they are, however, made mostly
of wood, as glass and porcelain are too expensive; slate has lately been em-
ployed in constructing milk coolers.” Tinned iron is, however, often used for
skimming dishes and other purposes; lead and glazed earthenware form many
of the utensils in some dairies, and cast iron has been recommended for the
same purpose: but it will be proper to observe that lead is poisonous, and so are
some of the metallic substances that enter into the composition which forms the
glazing of earthenware. Now, since milk contains acids capable of dissolving
these metallic compounds, it must follow that the use of them in a diary must
be very prejudicial. The human constitution must infallibly be injured by
imbibing these deleterious solutions; but the progress of the mischief is slow;
428 DECOMPOSITION.
and when at length the mischief is discovered, we seldom or never ascribe it
to the proper cause. Nor is the use of iron to be recommended, for though its
solution in the acid of milk may be harmless, yet the milk, butter, and cheese,
into which this solution enters, may be altered in their taste, and acquire new
properties from it. The best vessels and utensils for the dairy are, therefore,
those which are made of wedd, and which are kept in a sweet and clean state
by daily scalding, scouring, &c. The utensils which are most generally wanted
in a dairy farm, are milk-pails, skeels, bowls, strainers and coolers, churns,
lading and skimming dishes, cheese tub, ladders, vats, cloths, and presses. The
fitting a dairy, where one churn is used, with these utensils, will cost from
twenty to twenty-four pounds,-this is the estimated value in Gloucestershire;
in a farm consisting of twenty-five or thirty cows, the cost would probably be
double that sum, and so on, in proportion to the magnitude of the farm.
DAMAJAVAG. This singular name has been given to a preparation of
the chestnut tree, and is employed in tanning as a substitute for oak bark and
gall nuts: it is the subject of a patent granted to Charles Louis Giroud, of
queen-street, Soho, London, in 1825. The mode of preparing damajavag is
as follows : The external shell of the chestnut or the wood itself, is to be broken
into small pieces, and soaked in double its weight of water for twelve hours,
then boiled for three or four hours, when the liquid is to be drawn off, and
filtered through a cloth or sieve to separate the fibrous matter, The liquid
extract is now to be evaporated by returning it into the boiler, and the ebullition
is to be renewed and continued until the extract becomes of the consistency of
paste; after this it is to be cut into cakes, and dried in an oven for sale, or at
once applied to the various purposes in the arts, in lieu of gall nuts. One
hundred pounds of chestnut shells will thus produce about eight pounds of
damajavag. The sap of the chestnut tree contains similar properties to the wood
and the nut shell, but combined with a greater portion of mucilage. The trunks
of the trees may be tapped, the sap collected, and an extract made from it by
simple evaporation. Iron vessels should not be used in the preparation of dama-
javag, as that metal would darken the colour of the extract, owing to the affinity
between iron and the gallic acid of the chestnut, their combination producing ink.
DAMASK. The name given to silk or linen fabrics with a raised pattern on
the right side.
DAMASKENING. The art of beautifying iron, steel, &c., by making in-
cisions in them, and filling them up with gold or silver wire; it is chiefly used
for adorning sword blades, locks of pistols, &c. See IRoN.
DAVIT. A projecting piece of timber, used as a crane to hoist the flukes
of the anchor to the top of the bow of a ship.
DEAD LIGHTS. Strong wooden shutters for closing the stern windows of
ships in bad weather. - -
DEAD RECKONING. An account of the progress of a vessel, showing
the courses steered by compass, with the distance in miles and fathoms run
upon each course. These courses, corrected by allowances for leeway and
variation, and the distances by allowances for heave of the sea and currents,
form what is termed the corrected dead reckoning, which is used for ascertain-
ing the vessel's place upon a chart, in default of observations of the celestial
bodies to determine the same.
DEAL. A stout kind of plank made from the fir-tree by sawing the trunk
longitudinally.
DECIMAL ARITHMETIC, in general sense, denotes the common arith-
metic in which we count by periods of tens; it is otherwise and more properly
called denary arithmetic, to distinguish it from the binary, duodenary, and other
scales of arithmetic.
DECOCTION. A fluid which has been made to take up certain soluble
principles by boiling.
DECOMPOSITION, in Chemistry, the separation of the component parts
of bodies from each other. It is in general the effect of some new combination
amongst the constituent principles of bodies, the only exceptions being those
decompositions which are effected by heat or electricity.
L) ENDROMETER. 429
DECREPITATION. The crackling noise which several salts make when
suddenly heated, accompanied by a violent exfoliation of their particles. It
has been attributed to the sudden conversion of the water they contain into
steam; “but,” observes Dr. Ure, “it is the salts which are anhydrous, or
contain no water, that decrepitate most violently; those that contain water
generally enter into tranquil liquefaction on being heated.” Salts decrepitate
for the same reason that glass, quartz, and cast iron crack with an explosive
force, on being suddenly heated, namely, from the unequal expansion of the
laminae which compose them, in consequence of their being imperfect con-
ductors of heat. -
DEFLAGRATION. The act of burning two or more substances together,
as charcoal and nitre.
DEFLEXION, in Mechanics, the bending of any material exposed to a
transverse strain. . In all bodies so situated deflexion takes place; but whilst
the elastic force of the material exceeds the straining force, the deflexion will
be directly proportional to the pressure, and will not increase after the load has
been on for a second or two, and upon its removal the material will recover its
original form; but if the load exceed the elastic force of the material, the
extension or deflexion increases with time, a permanent alteration of form
ensues, and the deflexion increasing rapidly with slight addition to the load,
fracture ensues. The resistance of a material to flexure, as Mr. Tredgold
observes, is the only proper measure of its resistance, when it is to be applied
in the construction of buildings, and that of its resistance to permanent alteration
when it is used for machines. According to Mr.T.'s experiments, a bar of cast
iron, 4 feet long and 1.2 inches square, and supported at both ends, sustained a
load of 112 lbs. in the middle of its length without permanent alteration. The
deflexion with this load was one-tenth of an inch.
DEGREE, in Geometry, the 360th part of the circumference of a circle,
into which number of parts all circles are considered to be divided; it is
indicated by a small o near the top of the figure; thus, 450 is forty-five degrees.
Each degree is subdivided into sixty smaller parts, called minutes, and denoted
by the mark'; and these again are each subdivided into sixty parts, called
seconds, and marked thus "; thus, 450 12' 20" is forty-five degrees twelve
minutes and twenty seconds.
DELFT WARE. A kind of pottery, covered with an enamel or white
glazing, which gives it the appearance of porcelain. They are composed of a
fatty clay, with which is ground a portion of sand, that it may not crack or
shrink too much in baking. Vessels formed of this earth require to be dried
very gently, to avoid cracking; they are then slightly baked in a furnace, to
give them a degree of hardness; after which, the enamel, ground very fine and
diluted with water, is applied, and as the ware is very porous from being but
slightly baked, it readily absorbs the water, leaving a coating of enamel adhering
to the surface. The ware, when thoroughly dried, is then enclosed in cases of
baked earth, and subjected to a heat sufficient to fuse the enamel uniformly,
and at the same time to complete the baking. Delft ware was formerly made
chiefly at Delft, in Holland, from which town it takes its name.
DELIQUESCENT, in Chemistry, a property of various substances (chiefly
salts), to absorb moisture from the atmosphere, and dissolve.
DENDROMETER. An instrument for measuring trees, invented by
Messrs. Duncombe and Whittel. It consists of a semicircle, divided into two
quadrants, and graduated from the middle; upon the diameter there hangs
a plummet for fixing the instrument in a vertical position. The principal use
of it is for measuring the length and diameter of any tree perpendicular or
oblique to an horizontal plane, or in any situation of the plane on which it
rests; or of any figure, whether regular or irregular, and also the length and
diameter of the boughs, by mere inspection. The inventors of it have calcu-
lated tables, annexed to their account of the instrument itself, by the help of
which the quantity of timber in a tree is obtained without calculation, or
the use of the sliding rule. The dendrometer, fitted to a theodolite, may be
applied to measuring the heights and distances of objects accessible or inacces-
3 I
430 DETONATING JAR.
sible, whether situated in planes parallel or oblique to the plane on which the
instrument is placed. It may be also used for taking all angles, whether vertical,
horizontal, or oblique, in any position of the planes in which they are formed.
DENSITY is the proportionate quantity of matter in bodies of a given
magnitude; thus, if a body contains more matter than another, both being of
the same bulk, the former is said to be more dense than the latter, and that in
proportion to the relative quantities of matter they contain; or if the former
body contains the same quantity of matter as the latter, but under a less bulk,
its density is greater in proportion as its bulk is less than that of the other.
Hence the density is directly proportional to the quantity of matter, and in-
versely proportional to the bulk under which it is contained. The relative
quantities of matter in bodies are known by their gravity or weight; for, according
to Sir Isaac Newton, the original particles of matter being equal, and con-
sequently endowed with equal gravity, bodies, or assemblages of those particles,
will have a gravity proportionate to the number of particles contained in them.
Hence, when a body, mass, or quantity of matter is spoken of its weight or
gravity is always understood, that being the proper measure of the quantity of
matter. The density of bodies is found by weighing equal bulks of each; for
this purpose solids must be previously reduced to the same shape and size, but
each fluid should fill the same vessel, in which they must be weighed separately.
The density of fluids may also be determined by the following methods. First,
by Thaking an equilibrium between them, in tubes that communicate; for the
diameters of the tubes being equal, and the weights or quantities of matter also
equal, the densities will be inversely as the altitudes of the liquors in them;
that is, inversely as their bulk. Secondly, by immersing a solid in the fluids,
their densities may be readily compared; for if the solid be lighter than the
liquids, the part immersed by its own weight will be inversely as the density of
the fluid; but if the body be heavier, so as to sink in the liquid, it must be
weighed in them separately, and the weight lost by the body in each will be
directly as the density of the fluid, Sir Isaac Newton, and most of the other
philosophers, are of opinion that there is no such thing as a space absolutely
full of matter, and that consequently there is no substance in nature, either
solid or fluid, that is perfectly º : the densest bodies, according to Newton,
consist of much more porous space than solid matter.
DEPARTURE, in Navigation, the distance of a ship or place to the east or
west of any meridian, expressed in nautical miles, whilst the difference of
longitude is the same distance reckoned in degrees and minutes upon small
circles of the earth, termed parallels of latitude; and as these small circles
continually decrease as they approach the poles, and as every circle, large or
small, contains 360°, each containing 60', the length of the degrees and minutes
of longitude must vary with the latitude. -
DEPH LEGMATION. The operation by which bodies are deprived of
water, which is principally effected by evaporation. -
DEPH LOGISTICATION. The operation by which bodies are deprived of
phlogiston, or the inflammable principle, and nearly synonymous with what is
now expressed by oxygenation or oxidization.
DESCENDING CLOCK. A clock so constructed that by gradually rolling
down an inclined plane it shows the progress of time; the motion is com-
municated to the wheels by a weight, which revolve about the axis as the
clock descends. A drawing and description of this machine is given in Emerson's
Mechanics. * ,
DESIGNING is the art of delineating or drawing the appearance of objects
by lines on a plane; but the term is more generally understood to apply to the
first sketch of a work which it is intended afterwards to execute with greater
accuracy of detail or of finish, or upon a different scale of magnitude. A
design bears the same relation to drawing and painting as a model does to the
making of a machine or building. . -
DETENT, in Clock-making, a stop, which, being lifted up and let fall down,
locks and unlocks the striking parts of a clock. -
DETONATING JAR. An apparatus for firing a mixture of gases by
DETONATING POWDERS. 431
means of the electric spark. It consists of a thick glass tube, open at bottom,
but hermetically sealed at top, and having towards the upper part two small
wires cemented into it, which approach each other within the jar near enough to
communicate the electric spark from an adjoining machine, by which the gases
are fired.
DETONATING POWDERS, or FullMINATING Powders. Certain chemical
compounds, which, on being exposed to heat or friction, explode with a loud
report, owing to one or more of the constituent parts assuming the elastic state
with such rapidity as to strike the displaced air with great violence. The most
common detonating powders (except gunpowder), are fulminating gold, and
fulminating powder. This latter is made by triturating, in a warm mortar,
three parts by weſght of nitre, two of carbonate of potash, and one of flowers
of sulphur. When fused in a ladle and then set on the fire, the whole of the
melted fluid explodes with an intolerable noise, and the ladle is commonly
disfigured as if it had received a strong blow downwards. If a solution of
gold be precipitated by ammonia, the product will be fulminating gold. This
precipitate, separated by filtration, and washed, must be dried without heat, as
it is liable to explode with no great increase of temperature; nor must it be
put into a bottle with a glass stopper, as the friction of this would expose the
operator to the same danger. Less than a grain held over the flame of a candle
explodes with a very sharp and loud noise. Fulminating silver may be prepared
as follows: powder one hundred grains of nitrate of silver, put the powder into
a glass vessel, and pour upon it first an ounce of alcohol, and then as much con-
centrated nitrous acid. The mixture grows hot, boils, and an ether is visibly
formed, that changes into gas. By degrees the liquor becomes milky and opaque,
and is filled with small white clouds. When all the grey powder has taken this
form, and the liquid has acquired consistency, distilled water must be imme-
diately added, to suspend ebullition and prevent the matter from being redissolved
and becoming a mere solution of silver. The white precipitate is then to be
collected on a filter, and dried. The force of this powder greatly exceeds that
of fulminating mercury: it detonates in a tremendous manner on being scarcely
touched with a glass tube, the extremity of which has been dipped in concen-
-trated sulphuric acid. Fulminating mercury was discovered by Mr. Howard.
A hundred grains are to be dissolved with heat in an ounce and a half by
measure of nitric acid. The solution, when cold, is to be poured on two ounce
measures of alcohol, and heat applied till an effervescence is excited. As soon
as the precipitate is thrown down, it must be collected on a filter, that the acid
may not react on it, washed, and dried by a very gentle heat. It detonates
with very little heat or friction. Three parts of chlorate of potash, and one of
sulphur, triturated in a metal mortar, cause numerous successive detonations,
like the cracks of a whip, the reports of a pistol, or the fire of musketry,
according to the rapidity and force of the pressure employed. A few grains
struck with a hammer on an anvil explode with a noise like that of a musket,
and torrents of purple light appear around it. Six parts of the chlorate, one
of sulphur, and one of charcoal, detonate by the same means, but more strongly,
and with a redder flame. Sugar, gum, or charcoal, mixed with the chlorate,
and fixed or volatile oils, alcohol, or ether, and made into a paste, detonate very
strongly by the stroke, but not by trituration. Some of them take fire, but
slowly and by degrees, in sulphuric acid. Fulminations of the most violent
kind require the agency of azote or nitrogen, as we see not only in its compounds
with the oxides of gold, silver, and platina, but also still more remarkably in
its chloride and iodide, which form the two most violent detonating compounds
known. The first of these, viz. the chloride of azote, was discovered in 1812,
by M. Dulong, but its nature was first investigated by Sir H. Davy, who was
twice seriously wounded by explosions of the substance whilst operating upon
it. It may be prepared as follows: put into an evaporating porcelain basin a
solution of one part of nitrate or muriate of ammonia, in ten parts of water
heated to about 1000, and invert into it a wide-mouthed bottle filled with
chlorine. As the liquid ascends by the condensation of the gas, oily looking
drops are seen floating on its surface, which collect together, and fall to the
432 DIALLING.
bottom in large globules: this is chloride of azote. By putting a thin stratum
of common salt at the bottom of the basin, we prevent the decomposition of
the chloride of azote by the ammoniacal salt. It should be prepared only in
very small quantities. A small quantity of it thrown into a glass of olive oil,
produced a most violent explosion, and the glass, although a strong one, was
broken into fragments. It also detonates strongly when brought into contact
with phosphorus and many of its compounds, with various fixed oils, with oil
of turpentine, naphtha, fused potash, aqueous ammonia, nitrous gas, and various
other substances, but not with sulphur or resin. Iodide of azote may be most
readily prepared by putting pulverulent iodine into common water of ammonia.
It is pulverulent, and of a brownish black colour. It detonates from the
smallest shock, and from heat, with a feeble violet vapour. When properly
prepared, it frequently detonates spontaneously; hence, after the black powder
is formed, and the liquid ammonia decanted off, the capsule should be left in
perfect repose. Dr. Ure mentions, that in transferring a little of it from a
capsule of platina to a piece of paper, the whole exploded in his hands. It
should therefore be prepared with the greatest care, and in only very small
quantities, and should not be preserved.
DIACOUSTICS. The consideration of the properties of sound refracted in
passing through different media.
DIAGONAL, in Geometry, a right line drawn across a figure from the
vertex of one angle to the vertex of another. .
DI AGONAL SCALE. See ScALE.
DIAGRAM. A geometrical scheme for the explanation of the properties
of a figure, or for the illustration of machinery; in which case it differs from a
drawing, by the parts being represented by single lines without any breadth.
DIAL, or SUN DIAL. An instrument for measuring time by means of a
shadow cast by the sun upon a surface properly placed for the purpose. Sun
dials are an invention of very great antiquity, and are frequently mentioned in
the Bible; and Vitruvius speaks of one made by the ancient Chaldee historian,
Berosus, on a reclining plane, almost parallel to the plane of the equinoctial.
Before the invention of clocks and watches, dials afforded almost the only means
of marking the lapse of small portions of time; and dials were, therefore, gene-
rally to be seen in most places of public resort, as churches, crossways, mar-
kets, &c.; but since that invention, and the immense improvements made in
it, dials have gone gradually into disuse, and are now rarely to be met with in
England, where, indeed, the variable nature of the climate materially limits
their utility. On the Continent they are still to be met with; and one kind,
called the pillar dial, consisting of an elegant stone column, is frequently introduced
as an ornament in the squares and market places. Our ingenious neighbours,
the French, have likewise contrived a method of calling attention, at least once
in the day, to the silent progress of the shadow over the dial, by means of a
small mortar placed on the meridian line of a diá1 with a burning lens placed
over the touch-hole, at such a distance and angle, that as soon as the sun
arrives on the meridian, its rays, concentrated by the lens, set fire to the
powder, which discharges the gun, and thus announces the hour of noon.
“We take no note of time but from its loss:
To give it then a tongue is wise in man.”
Dials of this description are placed in the gardens of the Palais Royal, and of
the Luxembourg.
DIALLING. The art of drawing dials on any surface, plane or curved. On
account of the limited utility of this art, from the causes before noticed, we shall
confine ourselves to explaining the general principles of dialling, which may be aptly
illustrated by the phenomena of a hollow or transparent sphere of glass. Then
suppose a PB p to represent the earth as transparent, and its equator as divided
into 24 equal parts, by so many meridian semicircles, a b c, &c., one of which
is the geographical meridian of any given place, as London, which is supposed
at the point a ; and if the hour of 12 be marked upon that meridian, and
upon, the opposite one, and all the rest of the hours in succession on the other
meridians, those meridians would be the hour circles of London; because, as the
DI AMOND. 433
sun appears to move round the earth, which is in the centre of the visible
heavens, in twenty-four hours, he will pass
from one meridian to another in an hour.
Then, if the sphere had an opaque axis as
Pe P, terminating in the poles P and P, the
shadow of the axis, which is in the same plane
with the sun and with each meridian, would
fall upon every particular meridian and hour B
when the sun came to the plane of the oppo-
site meridian, and would, consequently, show
the time at London and at all other places on
the same meridian. If this sphere were cut
through the middle by a solid plane A B C D
in the rational horizon of London, one-half of
the axis e P would be above the plane, and
the other below it; and if straight lines were drawn from the centre of the
plane to those points where its circumference is cut by the hour circles of the
sphere, those lines would be e hour lines of an horizontal dial for London;
for the shadow of the axis would fall upon each particular hour line of the
dial when it fell upon the like hour circle of the sphere. Those who are further
interested in the subject we would refer to Emerson's Dialling, and Ferguson's
Lectures on Mechanics. Dr. Brewster, in the Appendix to his valuable edition
of this latter work, has described an analemmatic dial, which sets itself. Many
ingenious constructions of dials are also given in Dr. Hutton's Translation of
Montucla's Recreations.
DIAMETER, in Geometry, the line which, passing through the centre of a
circle, or other curvilinear figure, divides it or its ordinates into two equal
arts.
DIAMOND. The most brilliant and the most valued of all the minerals.
It is found of all colours—white, grey, red, brown, yellow, green, blue, and
black; the colourless varieties are the most esteemed. If very transparent and
pure, they are said to be of the first water; and in proportion as they depart
from this transparency and purity, they are denominated of the second or third
water. The extraordinary lustre of the diamond is said to be derived from its
reflecting all the light which falls on its posterior surface at an angle of inci-
dence greater than 24° 13'; artificial gems reflect only half this light. The
weight, and, consequently, the value of diamonds, is estimated in carats, one of
which is equal to four grains; and the piece of one diamond, compared to that
of another of equal colour, transparency, purity, form, &c., is as the squares
of the respective weights. The average price of rough diamonds that are worth
working is about two pounds for the first carat; and the value of a cut diamond
being equal to that of a rough diamond of double weight, exclusive of the price
of workmanship, the cost of a wrought diamond of
1 carat is . . . . . . . . . 39 £8
2 ditto is . . . . . . . . . 2” x 8 = 32
3 ditto is . . . . . . . . . 3" x 8 = 72
4 ditto is . . . . . . . . . 4” x 8 = 128
5 ditto is . . . . . . . . . 5” x 8 = 200
This rule is, however, not extended to diamonds of more than 20 carats
(value 3,2007.); the larger ones, in consequence of the scarcity of purchasers,
being disposed of at prices greatly inferior to their estimated worth. . It does
not appear that a larger sum than 130,000l. was ever given for a diamond,
which was brought by a gentleman named Pit, from India, and was hence
called the Pit diamond. Diamonds can only be cut and polished by their own
substance. The operation is commenced by rubbing several against each other
while rough, after having first glued them to the ends of two wooden biocks,
thick enough to be held in the hand. The powder thus rubbed off the stones

-134 DILATATION.
is received into a little box for the subsequent purposes of grinding and polish-
ing them. These operations are effected by a mill, which turns a wheel of soft
iron, on which is sprinkled the diamond dust, mixed with oil of olives; the
particles of diamond becoming imbedded in the soft iron by the rubbing action,
and presenting a multiplicity of opposing cutting angles to the stone under
operation, which is thereby shaped according to the design of the operator.
The same dust well ground and diluted with water and vinegar is used in the
sawing of diamonds, which is performed by an extremely fine iron or brass
wire; the operation being similar in principle to the sawing of blocks of stone
for the use of the mason, by means of sharp sand and a blunt blade of iron.
Brilliants are those diamonds which are cut in faces at the top and bottom,
and whose table or principal face at top is flat. Rose diamonds are quite flat
underneath, with the upper part cut into many little facets, usually triangles,
the uppermost of which terminates in a point. The only chemical difference
between diamond and the purest charcoal is, that the latter contains an
extremely minute portion of hydrogen. It is said that diamonds have been
recently artificially produced from charcoal. l
DIAPASON. An interval in music that expresses the octave of the Greeks.
This term is likewise applied to the rule or scale whereby musical instrument
makers adjust the pipes of organs, and cut the holes of hautboys, flutes, &c.
in due proportion, for performing the tones, semi-tones, and concords, with
precision.
DIAPER. A kind of cloth, on which is formed a variety of designs, chiefly
employed for table linen. See WEAviNg.
DICE. Small cubical pieces of bone or ivory, marked with dots on each
face, from one to six. To give uniformity to their figure, or to make true dice,
is of course a very simple art; but the ingenuity of the dice-maker is called
into action to construct false or untrue dice for the sharping gamester; for him
they are so skilfully constructed or loaded, as to ensure a preponderance of
favourable chances, without incurring the probability of the cause being dis-
covered. Some of their nefarious processes are known to us, but it is not our
province to extend the knowledge of so vile an art.
DIFFERENCE is the remainder after taking the less of two quantities from
the greater.
DIFFERENTIAL, in the higher Geometry, is an infinitely small quantity,
or part of quantity, so small as to be less than any assignable one, and is thus
denominated because it is frequently considered as the difference of two
quantities, and as such, is the foundation of the differential calculus. The
term differential is also applied, in Mechanics, to various machines for imparting
to a body the difference of motion of two other bodies moving in contrary
directions; an example of this is shown in the Chinese crane, under the
article CRANE. For further instances, see PULLEY DIFFERENTIAL, Screw
Diff ERENTIAL, and WHEEL DIFFERENTIAL.
DIGESTER. A strong vessel formed of iron or copper, the lid of which
screws down, and is made tight by luting or grinding; and the steam not
being allowed to escape, the water acquires a very high temperature, by which
its solvent powers are greatly increased. To prevent accidents, a small safety
valve is inserted in the lid. The digester is the invention of the celebrated
Papin.
#3rt, in Arithmetic, any one of the ten numerals 1, 2, 3, 4, 5, 6, 7, 8, 9, 0;
also a measure equal to three-quarters of an inch.
DILATATION. The expansion of a body into a greater bulk by its own
elastic power. It differs from rarefaction: for though the effects of both are
nearly, if not quite the same, yet the latter arises from the application of heat.
It has been observed by modern philosophers, that bodies which have been
compressed and are again set at liberty endeavour to dilate themselves with a
force equal to that by which they are compressed; accordingly they are found
to sustain a force and raise a weight equivalent to the force of compression.
Bodies in the act of dilating by their own elasticity exert a greater force at the
beginning than towards the end, as being at first more compressed; and the
DISTILLATION. 435
greater the compression is the greater is the elastic power and endeavour to
dilate: hence the compressing power, the compression, and the elastic force,
are necessarily equal, and may be taken the one for the other. The motion
by which compressed bodies restore themselves is usually accelerated, though
sometimes not. When compressed air begins to restore itself, and dilate into
a larger space, it is still compressed, consequently new impetus is continually
impressed upon it by the dilatative cause ; and the former remaining with this
continual addition, the effect, namely, the velocity, must likewise evidently be
increased. But it may also happen, that where the compression is only partial,
the motion of dilatation will not only not increase, but be even retarded, as
is the case when sponge, soft bread, gauze, and other similar bodies, are
compressed. -
DIOPTRICS. The doctrine of refracted vision, which investigates and
explains the effects of light refracted by passing through different media, as
air, water, glass, &c.
DISTILLATION. The art of obtaining in a separate state, by the appli-
cation of heat, the more volatile parts of bodies; but the term is generally
limited to signify the separation of volatile liquids, for when the volatile product
is obtained from a solid, and assumes a solid form, the operation is termed
sublimation. In the distillation of liquids the most volatile parts rising in
vapour first are conducted to variously disposed refrigerators, usually composed
of metal, and surrounded with cold water, which, abstracting a portion of heat
from the vapour, it becomes condensed, and assumes a liquid form. One of
the principal applications of the art of distillation is the preparation of spirituous
liquors, which is usually divided into two branches. The first, termed distillation,
consists in separating the spirituous parts of fermented liquors, mixed with a large
portion of water, from the fixed or nonvolatile parts; and in the latter branch,
termed rectification, the spirit is concentrated and purified principally by means
of redistillation. Having already treated largely upon the various methods of
effecting this, under the head Alcohol, we shall in this place limit ourselves
principally to the description of the preparatory process of distillation, together
with some of the most approved apparatus employed therein.
In London and its neighbourhood the process of forming the wash for
distillation is the same as in brewing for beer, except that no hops are used,
and that instead of boiling the wort they pump it into coolers, and afterwards
draw it into backs, to be then fermented with yeast. During the fermentation,
considerable attention should be paid to the temperature of the liquid, which
should be steadily maintained at about 700 Fahr., and the fermentation is
continued until the liquor grows fine and pungent to the taste, but not so long
as to allow acetous fermentation to commence. In this state the wash is put
into the still (of which it should occupy about three-fourths), and distilled with
a gentle fire as long as any spirit comes over, which is generally until about
half the wash is consumed. The form of the common still is too well known to
need any particular description. It generally consists of a large boiler made
of copper, and fixed in masonry over a fire-place. The boiler has a head, or
capital, as it is called, which is of a globular form, to which is soldered a neck,
forming an arch curved downwards, and fits into what is called the worm ; this
is a long tube, made generally of pewter, of a gradually increasing diameter;
it is curled round in a spiral form, and enclosed in a tub, which is kept filled
with cold water during distillation. That celebrated philosopher and mechanic,
the late Mr. Watt, having ascertained that liquids boil in vacuo at a much
lower temperature than when under the pressure of the atmosphere, endeavoured
to turn this circumstance to advantage in distillation, under the idea that less
fuel and also less water for condensation would be required; but found, by
experiment, little or no advantage in this respect, the latent heat of the vapour
being nearly the same, whether formed in vacuo or under the pressure of the
atmosphere. The idea of distillation in vacuo was subsequently taken up by
Mr. Tritton, as affording a means of preventing any empyreumatic flavour
being imparted to the spirit by the burning of any matter contained in the still,
as a heat considerably ſess than 212° Fahr. is sufficient to cause the wash to
436 DISTILLATION.
boil rapidly in vacuo. The annexed diagram exhibits a section of Mr. Tritton's
apparatus for distilling in vacuo. A is the body of the still ; B is a water
bath, into which the body of the still is immersed; C is the head or capital,
D the neck of the same, which, curving downwards, is connected with a pipe
that enters the condensing vessel E.; F is a refrigera ory or close vessel, con-
taining cold water, for converting into liquid the spirituous vapours, which,
having been raised in the still, are contained in the vessel E. From the bottom
of the vessel E a pipe issues, for conveying the liquid
and the vapour not yet condensed into vessel G,
which being surrounded with cold water contained in
the vessel H, acts also as a refrigeratory, and reduces
the whole of the remaining vapour into a liquid state.
I is an air pump for effecting a vacuum in the vessels
A E G ; K is a stop-cock for cutting off the commu-
nication between the vessels E and G, when the
contents of G are drawn off by the cock M, by which
means a vacuum is preserved during that operation in
the vessel E and the still A. L is an air cock, to
admit air into the vessel G, to allow the contents to
run out at M ; N is the discharge cock to the still A.
It will be seen that the greatest heat to which the
matter in the still can be subjected can never exceed
2120 Fahr. ; but upon the pressure of the atmosphere
being removed by means of the air-pump, the dis-
tillation is effected at the low temperature of 1320 Fahr.,
by which means all injury to the flavour of the spirit,
by carbonization of the matters contained in the still,
is entirely avoided.
Dr. Arnott, in his work on the Elements of Physics,
proposes a mode of distilling or evaporating in vacuo,
without the aid of an air pump, by simply establishing
a communication between a close distilling or evapo-
rating vessel, and the top of a water barometer. The
principle of this method will be readily comprehended
by referring to the annexed diagram and its accom-
panying explanation. a is the evaporating vessel or
still, the neck of which communicates with a strong
vessel b, forming the top of the barometer; from the
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under side of b proceeds a tube, plunging in a small vessel d, situated 36 feet
below the bottom of b, . The cocks at d and e being shut, the vessel b and the
descending pipe are to be filled with water through a cock c at the top; then



DISTILLATION. 437
this cock being shut, and the cock at d opened, the water will sink down out of
the vessel b until the column in the tube be only 34 feet high, as at f, that
being the height which the atmosphere will support. On opening a commu-
nication between the vessel a and the vacuum in b, the operation goes on as
desired, and the steam arising from a may be constantly condensed by allowing
a small stream of water to run through b from above, in cases where it is sought
to concentrate any liquid in a in vacuo; but for distillation, where the condensed
vapour is the product which is sought, the water must be applied externally to
b, by placing that vessel in another vessel g, kept constantly full of water. If
the vacuum becomes destroyed by the accumulation of the air extricated in
boiling, it may be easily restored by refilling b as at first. Dr. Arnott states
that he planned this arrangement as a simple apparatus for the preparation of
medicinal extracts, as many watery extracts from vegetables have their virtues
impaired or destroyed by a heat of 2120; but when the water is driven off in
vacuo, the temperature need never be higher than blood heat. The doctor
further observes, that this plan appears “particularly well suited to the colonies,
where air-pumps and nicer machinery can with difficulty be either obtained or
managed.”
The annexed engraving represents Sir Anthony Perrier's improved apparatus
for distillation. The object of this invention is to cause the liquid to flow
gradually over the heated surface of the body of the still, and during its
progress to give out its spirituous vapour, and to maintain a continuous and
|
a T
uninterrupted distillation as long as the supply of liquid is furnished and the fire
kept up. Fig. 1 is a view, in profile, of the section of the still, and Pig. 2 is a
plan of the same. The bottom of this boiler is divided by concentric partitions,
which stand up, as in Fig. 1, sufficiently high to prevent the liquor from boiling
over. These partitions have openings from one to the other at opposite sides,
so as to make the course a sort of labyrinth. f is a reservoir of liquor prepared
tor the operation; g is a pipe or tube descending from the reservoir, and

3 k
43 DISTILLATION.
conducting the liquor to that part of the boiler marked h, which is the commence-
ment of the race. From hence the liquor flows through the channels, as shown
by the bent arrows, progressively traversing the whole surface of the bottom,
whereby the full effect of the fire is exerted upon small portions of the liquid,
which causes the evaporation to proceed with great rapidity. The residue of
the liquid then passes off by the discharge pipe i, which is made to slide, for
the purpose of regulating the quantity and depth of fluid in the still; and this
pipe should be in such proportion to the admission pipe, as to cause the perfect
distillation of the liquor in its passage to the regulating tube. In the still, as
shown at Fig. 1, a set of chains are seen suspended from a bar i i, supported
by a centre shaft, which may be put in motion by a toothed wheel and pinion,
actuated by a crank or winch. These chains hang in loops, and fall into the
spaces between the partitions, for the purpose of sweeping the bottom of the
still, and preventing the material operated upon from burning, when of a thick
or glutinous nature, as turpentine, syrups, &c.
In the still we are now about to describe, invented by Mr. Frazer, of
Houndsditch, the object is the economizing of fuel, and the production of a pure
spirit, by a peculiar arrangement of the vessels employed, that shall at the same
time be in perfect accordance with the existing excise laws. The wash still,
instead of being exposed to naked fire, is immersed in boiling water, the vapour
from the former enters the low wine still, where it is condensed ; the wine thus
abstracts the heat from the wash, becomes itself vapourized, and is conducted
into a refrigeratory; the first and second distillations are in this manner con-
ducted together by a continuous process, which will be best understood by a
reference to the annexed diagram. a is a supposed steam engine boiler, or
s.
other similar vessel, the heat from which boils the wash (or low wine) in the
still b. To prevent the liquid from boiling over into the condenser, the neck is
formed of the shape shown at i ; from hence the vapour passes through a steam-
tight case e, immersed in a reservoir c, containing either wash or the product
of the first distillation, where it becomes partly condensed; the vapour and
condensed liquid then descend through the worm beneath, wherein the

DISTILLATION. 439
condensation is completed and the liquid cooled, which then runs into the closed
recipient d underneath. This recipient d therefore contains the weak spirit of
the first distillation, called low wines, to re-distil which product it is raised by
the pump f, and discharged into the reservoir c, which is, in effect, the low
wine still. The liquid in this vessel, as before mentioned, is vapourized by the
heat of the vapour from the wash still passing through it; it is afterwards
condensed in the refrigeratory g, and finally received into the closed vessel
h, where the operation is completed.
The engraving on p. 440 represents the patent distilling apparatus of Mr.
Stein; in appearance it greatly resembles those constructed in France upon the
plan of Woolf's apparatus; but the principle of its operation is totally dif-
ferent, the object being rather to cause a great economy in the consumption of
fuel, than to obtain spirits of any required strength at a single operation. The
heat absorbed in the conversion of a given weight of water into steam, exceeds
greatly that which is required to raise its temperature to the boiling point; a
pound of water converted into steam raising six pounds of water to the point of
ebullition. The heat thus developed varies in different liquids, but is in all
cases considerable; and as distillation is ordinarily conducted, this heat is not
merely lost, but occasions a considerable additional expense, from the great
quantity of water required to reduce the vapour to the liquid state. To obviate
these two sources of loss, the patentee has contrived his apparatus, so that one
portion of liquid formed into vapour shall be reduced to the liquid form by
another portion of liquid, which is evaporated by the heat given out in the
condensation. But to convert a fluid into steam, not only a certain quantity of
heat is required, but the heat must also be of a certain intensity; thus, although
a pound of steam at 2129, would raise six pounds of water to the boiling point,
it would convert no portion of it into steam, as the moment the water had
acquired the heat of the steam, it would receive no further portion of heat from
it; but if the steam is formed under a pressure exceeding that of the atmosphere,
its heat, as indicated by the thermometer, is increased, and consequently it will
continue to impart heat to a liquid which has attained the boiling point under a
less pressure than the steam employed to heat it. Upon the combination of these
two principles, Mr. Stein's apparatus is constructed. Nos. 1, 2, 3, and 4, are
four oblong elliptical vessels or stills, two of which are shown in section ; the
lowermost halves are enclosed in casings a a, forming thereby steam chambers
b b; each still has a vertical pipe c c c c, terminated by a double passage cock
d d, one passage opening into the pipe e, which leads to the worm tub, whilst
the other opens a communication from one still to the steam case of the next
still, by means of the curved pipes fff; that from the still 1 leading to the
steam case of still 2, and so on in succession. The stills are charged from the
pipeg, the quantity admitted being regulated by the floats h; each steam case
communicates by the pipes l l l l (which are furnished with cocks) with the pipe
A proceeding from the boiler. From the lower part of the steam case proceed
pipes ºn m ; that from still 1 leads to the cistern, which furnishes the steam
boiler with hot water, whilst the others may either communicate with one
common main n, leading to a refrigerator, or they may each communicate with
a separate refrigerator. From the upper part of each steam case proceeds a
pipe (shown at 3 and 4) which communicates with a gauge pipe p p, and ter-
minates in a syphon barometer q q. ºr r r r are the man holes to each still;
ss ss the discharge pipes to the stills, * steam cases being emptied by opening
cocks in the pipes m m leading to the main n. The operation is as follows:—
The stills being charged, and the cocks d being open to e, the steam is admitted
to each case by the pipes l l leading from the steam pipe k, and is rapidly con-
densed in the steam case, the air escaping by a pipe not shown in our drawing.
When the liquor in the stills has nearly attained the boiling point, the steam is
shut off from all the cases except that of 1, and the cocks d are opened to the
pipes f, and the main n, being cleared of the condensed water, the cocks on m
of 2, 3, and 4 are closed. The steam from the boilers (which is under consider-
able pressure) continues to flow into the case 1, and by the heat given out to
the liquor in the still, causes it to boil; the vapour passes into the steam case
440 DISTILLATION.
of 2, and the liquor in 2 condenses the steam in 1, until a common temperature
is attained; then the steam from 1 being no longer condensed, and continuing
still to receive heat from the boiler, its pressure, and consequently its temper.
ature, increases, and it again gives out heat to the liquid in 2, which causes it
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to boil. The vapour from 2 then passes into the steam case of 3, where the
same process ensues, and which is subsequently repeated under the still 4, the
steam from which passes by the pipe e to the condenser. As soon as the
liquids in 2, 3, and 4 begin to boil, the cock on m must be partially opened to
allow the condensed spirit to pass by the pipe n to the refrigerator; yet always












DISTI L I, ATION. 441
retaining a certain portion in the steam case, the height of which may be
ascertained by the gauge pipe p, whilst the barometer q q will indicate the
pressure of the steam in each steam case. The proper pressures will be best
obtained by observation, as it will vary in different liquors during the distilla-
tion. The person conducting the process must, therefore, pay great attention to
the barometer; and to enable him to do this with facility, the gauge pipes and
barometer are all ranged in a cluster at the centre of the apparatus. By this
mode of distillation, it will be seen that the latent heat of three-fourths of the
liquid evaporated is saved, which produces a corresponding saving in the article
of condensing water.
In Mr. Williams's apparatus for distillation, for which he obtained a patent
about the year 1821, the improvements projected are comprised under the
following heads; viz. an enlarged capacity of the still head, to cause a separa-
tion of the aqueous vapour by condensation, previous to its passing over the
neck of the still into the spirit condenser; in the employment of numerous
small vertical tubes, surrounded with cold water, to increase and accelerate the
condensation; in the adaptation of a peculiarly constructed “cooling worm,”
by which it is conceived the quantity of spirit will be increased, by preventing
evaporation in its progress to, and when in the receiver; and in the employ-
ment of refrigerating saline mixtures, for the more effectual cooling of the spirit
in warm, climates, or in warm weather. In the body of the still (that part
where the vapour is generated) there is no improvement proposed, but an
enlarged capacity of its globular head, to cause the watery º to fall back
into the still ; this part of the apparatus we have omitted in our diagram, as
it requires no additional explanation; the engraving, therefore, relates wholly
to the †. for condensation, a is the termination of the neck of the
still, which conveys the vapour into the “upper drum” b, whence it is divided
among a number of small vertical tubes c, which the patentee says, should not
exceed three-fourths of an inch in their interior diameter. As the tub inclosing
this apparatus is filled with cold water, the condensation immediately com:
mences in the upper drum, and is completed in its subsequent progress through
the vertical tubes, and the “lower drum” d. From thence the fluid runs


442 DISTILLATION.
down a central neck e into the trap f from the upper part of which trap it
enters the cooling worm b. It is evident that the trap f is, in working, always
partly filled with liquid; and the neck e being immersed therein, any vapour
which may have escaped condensation can pass no further. The trap f has a
funnel-shaped bottom, from which a pipe h passes through the coils of the
worm, and through the side of the tub, where it is furnished with a cock for
the purpose of drawing off any impure spirit which may be separated from
the wash in the first stage of the process, and to discharge what may remain
in the trap when the process is over. To the trap f is also attached another
pipe i, called the safety pipe, for the purpose of allowing the egress and ingress
of atmospheric air from and to the condenser, to prevent both pressure and
vacuum therein. The coils of the cooling worm are made octangular; the
worm itself is made flat, and of considerable breadth ; a transverse section of
it is exhibited in the separate figure k, which shows it to be in the form of a
parallelogram, whose longest sides are four inches, and its shortest half an inch
wide. This octangular worm, after making six complete turns, assumes a cir-
cular shape, and diverges off to pass through the side of the tub; at its end
outside the tub, which is made a little tapering, is fitted, and is to be occasion-
ally applied, a crane-necked pipe l, which pipe may be elevated or depressed at
pleasure, for the purpose of keeping three or more of the coils of the worm full
of liquid. This crane-necked pipe is intended to be applied in hot weather, or
hot climates, to cool the spirits more effectually, and prevent their evaporation,
by subjecting the same in a greater degree to the effect of the cold water in
the worm tub. An additional apparatus, to be used in hot climates, of un-
doubted utility, is likewise recommended by the patentee, and claimed by him
as his invention. It consists of another pipe m, into which the discharging
end of the crane-necked pipe is made to enter; and which pipe, after passing
the end of the trough n, is made of a very broad, flat shape, and running the
whole length of the trough (which may be of any extent); it is then to return
by a very slight descent, so as to run back very gently into the funnel of the
pipe which conveys it into the receiver. The trough n is to be filled with
Glauber's salts and nitre, or any saline mixture capable of producing intense
cold, for the more effectual cooling of the spirit. The trough may be placed
upon wheels and axles, for the convenience .# bringing it to and conveying it
from its required situation.
Distillation is very commonly practised in India; and although the apparatus
is of the most simple, (not to say rude) description, the products are generally
of such excellent quality as to render the process deserving of the consideration
----->
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ºf the British manufacturer to discover the cause. The still commonly used
by the natives of Ceylon is represented in the above cut. It is constructed











DISTILLATION. 443
wholly of earthenware, excepting the tube of communication between the
alembic and the refrigeratory, which is of bamboo. b is the body (or boiler)
of the still ; a is the capital, luted with clay to b; c is the bamboo tube, which
conducts the vapour into the receiver d, where it is condensed by being
immersed in the vessel of cold water e. It is with this rude apparatus,
(according to Dr. Davy,) that the Singalese distil in the open air that fine
spirit arrack, which is obtained from toddy, the fermented juice of the cocoa
nut.
The editor of the present work, having a few years back had his attention
called to the state of the arts and manufactures in Ceylon, and of the implements
connected therewith, with a view to the improvement of the same, published
a series of papers on the subject, in a periodical work which he at that time
conducted, suggesting such alterations as seemed to him practicable with the
simple means and resources at the disposal of the natives; and the Ceylonese
still, just described, appearing to him to possess considerable merit, he proposed
the following modification of it, in which, whilst the best features of it are
retained, it is rendered in some respects more efficient, fuel and labour are
economized, and by a simple method of combining several small stills, an
apparatus is constructed adapted to operations on a more extended scale, a a a a
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are the heads of a series of earthen boilers, of the kind described above,
but instead of being exposed to the air, they are set in a close furnace b b,
built of clay, or of the same materials with which their pottery is formed. This
furnace is proposed to be built in a circular form, to any convenient extent, so
as to surround wholly or partially the other parts of the apparatus; it is for
this reason shown in the drawing as broken away, after being extended suffi-
ciently to allow of five vessels being fixed therein. The curved figure of the
furnace is given to it chiefly with the view of affording a convenient means of
connecting the bamboo tubes which conduct all the vapours from the several

444, DIVING APPARATUS.
stills into the cylinder d. This cylinder is fixed firmly in a closed vessel e,
which serves both as a recipient for the condensed liquid, and as an enlargel
chamber for the vapours. On one side of the cylinder d there is an oblong
aperture, made longitudinally for the egression of
the vapours, which is covered by a light piston, so
that when the vapours have attained but a very little
more elastic force than is sufficient to overcome the
pressure of the atmosphere, this piston is lifted, which
uncovers the aperture to a certain extent, and per-
mits the vapours to pass through a large bamboo tube
of communication into a thin metal refrigerating
box l; this metal box is supported by a strong tube
o, fixed into the close recipient p, the tube being
open to both. On the top of the cylinder is fixed
a vertical standard, the upper end of which be-
comes the fulcrum to a lever crank i. To one end
of this crank is jointed a rod or stout wire, which
connects it to the handle of the water valve k : the
other arm of the crank lever passes between anti-
friction rollers on the piston rod h. It will be mani-
fest by this arrangement, that in exact proportion to the volume of vapour
that escapes from the cylinder, will the precise quantity of water necessary to
condense it be showered down upon the refrigeratory; and this is done
uniformly and according to circumstances, without any attention on the part
of the distiller. By the elevation and
depression of the piston rod k also,
the long arm r of the lever crank d
may, by means of a cord s, be made
to open a sliding door or damper to
the furnace, by an arrangement for
this purpose omitted in the rough
sketch. As it is objectionable to leave
the still-heads exposed to the air, by
which a portion of the vapour be- sº
.* <2*.*.*.*.*.*.*.*.*.*.*.*.*.*,
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comes condensed and runs back into
the still, it is proposed to enclose them §
with a cap of wood or pottery, like that
delineated in the margin above, which
will envelope them in a heated atmo-
sphere. To prevent the escape of the
heat through the clay walls of the
furnace, they are made double, with a
stratum of charcoal between, as repre-
sented in the annexed sectional view,
in which a a represents the strata of charcoal imbedded in the surrounding clay;
b the boiler; c the head, luted to the boiler enclosed in the box d, through an
aperture in which the neck e passes, that conducts the vapour to the cylinder;
the cavities round the boiler f f are for the heated air, and g the hearth, on
which the wood is thrown at one end of the furnace.
DIVING APPARATUS. Contrivances for the purpose of enabling per-
sons to descend and to remain below the surface of the water for a great length
of time, to perform various operations, such as examining the foundations of
bridges, blasting rocks, recovering treasure from sunken vessels, &c. The appa-
ratus most commonly employed for this purpose is the diving bell, the invention
of which is generally attributed to Dr. Halley. These machines have been
variously modified, but are now ordinarily made in the form of an oblong
chest, open at the bottom. It is made of cast iron of considerable thickness,
and has several strong convex lenses set in the upper side or roof of the bell,
to admit light to the persons within. It is suspended by chains, hooked to
strong staples in the upper part of the bell, and which chains are passed round
N
~.º:
". #: *
*-*------------.






























DIVING APPARATUS. 445
a windlass supported upon the sides of two lighters or barges, so that the bell
can be raised or lowered, upon signals to that effect from the persons within the
bell, who are supplied with fresh air by means of a flexible hose passing under
the lower edge of the bell, and connected with a set of forcing pumps placed
in the barges. The air which has been respired being heated, rises to the
upper part of the bell, , Sence it escapes by a cock, An apparatus has also
been devised to enable a person to quit the diving bell, and remove to a con-
siderable distance when requisite, and still to receive the necessary supply of
air. It consists of a copper helmet, fitting water-tight to the shoulders of the
wearer, and furnished with a mouth piece, to which is attached a flexible hose,
reaching under the bell; but recently a patent has been obtained by Mr. W. H.
James for a somewhat similar apparatus, by which a diver can carry on the
necessary operations independently of a diving bell. The diver is attired with
a portable vessel (placed around and adapted to the figure of his body,) which
is filled with condensed atmospheric air; and by means of a simple arrange-
ment of pipes, and judiciously constructed valves, he is enabled to supply hun-
self with fresh air for respiration during the time he is under water. In the
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two accompanying figures, the letters in each refer to the same parts. Fig. 1
gives a front view of the diver fully equipped in the apparatus, and supposed to
















































3 L -
446 DOCKS.
be engaged in recovering from the deep a variety of sunken property; and
Fig.2 gives a section on a larger scale, for the better understanding of the
several parts. A is the vessel to contain the
condensed air, which is to be filled by means
of a condensing air-pump; it consists of a
series of strong metallic tubes, or of one con-
tinuous tube, coiled elliptically round the body,
and connected together by bands, to which
straps are attached to secure it in its position.
At a is a valve opening inwards, through which
the air is to be forced by means of a condensing
pump, until it has acquired the required degree
of density, which will, of course, be determined
by the time it is proposed for the diver to remain
under water. B is a tube made of caoutchouc
(or Indian rubber), for conveying the air into
the water-tight helmet C, by means of a valve
so contrived as to be completely under the
control of the diver. This helmet may be #
made of any water-tight material, but thin ſº
copper is recommended; it is provided with a flº
strong plate of glass in front, to enable the X:
diver to see surrounding objects Inside the
helmet is a flexible tube c, with a mouth-piece
at the end, which comes near to the mouth of
the diver; through this the air is discharged
from his lungs, and passes out through a valve
d in the top of the helmet. At the lower part
of the helmet, and round the breast, back, and
shoulders, a water-proof garment e is attached,
fitting closely round the body of the wearer,
and made fast by elastic bandages f. To
secure the diver from being inconvenienced by the pressure of the air within
the helmet becoming too great, a safety-valve is introduced. Notwithstanding
the weight of the apparatus (amounting perhaps to 50 lbs.), the density of the
water at great depths would render the body of the diver too buoyant to keep
on his legs and execute his work; in these cases it will become necessary to
attach weights to his person, capable of being easily removed, if desired;
some are therefore shown in the figures as attached to the apparatus; these,
however, it may be desirable to place lower down his person, about his legs and
feet. The same apparatus (divested of the weights) may be jºi with
safety and advantage in mines and other places filled with deleterious
a.SeS,
DOCKS. Enclosed excavations or basins, formed for the reception of
shipping. There are two descriptions of docks, viz. wet docks, and graving or
repairing docks. Wet docks are extensive basins formed adjacent to rivers and
harbours, with which they are connected by means of a lock, furnished with
gates at each end, so that vessels remain affoat at all times of the tide. They
are usually surrounded with warehouses, for the purpose of loading or dis.
charging vessels. The wet docks in this country are numerous and extensive,
and have proved highly beneficial to its commercial interests; as in these
ships lie in F. security from storms and depredation, their cargoes are
taken in and delivered with the utmost dispatch, and the navigation of the
rivers is freer from obstruction. The town of Liverpool, which, from the
badness of its harbour, resorted to the construction of wet docks in 1708, has
at the present day a range of them in front of the town, and along the banks
of the river Mersey, extending more than two miles in length, and which, from
their concentration in one spot, form the most striking display of the kind that
can any where be met with. Hull, Bristol, and Leith, have successfully emu-
lated this example. Although London was without the conveniences of wet

DOCKS. 447
docks until the commencement of the present century, it can now boast of
several, some of which exceed in magnitude any in other parts of the kingdom.
The first of these undertakings was the West India Docks, for the accommodation
of the West India trade, erected under an Act of Parliament passed in July,
1799. The great basin is 420 yards in length, and 230 yards in width, covering
an area of twenty acres. A basin of nearly three acres connects it with the
river. The warehouses are most noble buildings; the tobacco warehouse is
the most spacious erection of the kind in the world, being capable of containing
25,000 hogsheads of that article, and the vaults underneath, as many pipes of
wine. This single building under one roof is said to occupy upwards of four
acres of ground. These docks were opened in 1805. The London Docks were
begun in 1800, and completed in 1805. The principal basin is 420 yards in
length, and 276 in width, giving an area of 25 acres. The principal range of
warehouses occupies a superficies of 120,000 square yards. The first stone of the
East India Docks was laid in March 1825, and the first vessel entered them in
August 1826. The dimensions of the dock for unloading inwards are 1410
feet in length, and 560 in width; the dock in which vessels load outwards is
780 feet long, and 520 feet wide; and the entrance basin, which connects them
with the river by a lock, is 23 acres in extent. The lock is 210 feet in length,
the width at the gates 48 feet in the clear, and the depth of water at ordinary
spring tides 24 feet. The warehouses at these docks are of trifling extent, the
principal part of the cargo of vessels unloading here being conveyed in vans
direct from the ships to the East India Company's warehouses, situated in
various parts of the city of London. Besides these principal docks just enu-
merated, there are various others in the port of London, which our limits will
not allow us to notice.
Graving or Repairing Docks are excavations sufficiently large to admit one
or sometimes two vessels for the purpose of being repaired. At the entrance
is a pair of gates, forming an angle outwards or towards the river. When it
is required to dock a vessel, the water is admitted by means of sluices, and
when it has attained the same level within the dock as without, the gates are
opened, and the vessel hauled in over a range of blocks previously laid on the
floor of the dock; the gates are then shut, and the vessel, being steadied by
shores or props placed against the side of the dock, as the tide recedes, settles
upon the blocks. At low water the sluices are shut, and the water (if any)
remaining in the dock is pumped out, so as to leave it perfectly dry, and
to allow any part of the vessel's bottom to be examined and repaired. When
the soil is of an unfavourable nature for excavations, as also with a view
to avoid the delay which often occurs from ships being able only to enter some
repairing docks or to leave the same at the height of the springs, a contrivance,
called a floating dock, has been proposed, in which vessels may receive the
necessary repairs. Various constructions have been offered for this purpose. The
engraving on the following page represents a design for a floating dock, by Mr.
Edward Clark, of New York, civil engineer. This dock is proposed to be con-
structed by forming a float of timber to constitute the bottom of the structure,
and which, by its buoyancy, shall support a vessel within the dock with its keel
above the surface of the water. To attain this end the float is made in the form
of a hollow box, composed of strong logs firmly jointed together and caulked,
so as to render it water-tight. The capacity of the hollow part must be such
that, when exhausted of water by means of pumps, it shall be sufficiently buoyant
to sustain itself with its load. a represents the float; b b the piers, forming a
recess to steady and secure the float; c c perpendicular supports and braces
appended firmly to the piers; d d also supports appended firmly to the float, so
as to allow by means of the rollers e e of the easy and steady ascent and
descent of the float conformably to the motion of the tides and waves, and also
of sinking and raising the float in the same place; f the stern of the vessel;
g g bilge blockings; h h braces, all for supporting and steadying the vessel in
an upright position; i timbers framed into the piers, forming a bed for the
support of the float while sunk. The float a is supplied with valves and pumps
(not shown in the 'ngraving); and if it be required to float the vesself, nothing
448 DRAG SHEETS.
more is necessary than to open the valves, when the float, being previously
ballasted, will fill with water and sink to its bed. The vessel f being now
removed, and another made to occupy its place by means of guides, the valves
are to be closed, and the pumps put in motion, and when a quantity of water
has been displaced from the float equivalent to the weight, she will be elevated
entirely above the water, and placed in a most favourable situation to undergo
repairs. A float of this description, for use in sea water, would require to be
coppered externally, and occasionally to be filled with some other saline fluid,
or with fresh water, to preserve it from worms. The Committee of the Franklin
Institution at Philadelphia, to whom this invention has been submitted by
Mr. Clark, state, in their report thereon, that the main objection to docks of
this description, made sufficiently capacious for vessels of large dimensions, and
for the operations to be carried on in repairing them, is the unequal pressure to
which their bottoms must be subjected by the weight of the vessel upon them,
and the upward pressure of the water. They are aware that, by judicious
shoring, much of the weight of a vessel may be distributed over the bottom ;
this, however, although it would lessen the objection, would not remove it.
Ships, although constructed in a shape and braced in a manner calculated to
render them stable, undergo in nearly every instance a change of form after
they are launched; to this change of form the float in question would be much
more liable, inasmuch as its flat surfaces are less calculated to resist the effects
of the pressure to which they are subjected.
DODECAGON. A regular polygon of twelve sides.
DODECAHEDRON. A solid, having twelve equal and similar sides or
faces, each of which is a regular pentagon. -
DOVETAIL is a term implying a mode of connecting two pieces of wood
or other substance together by means of cutting their extremities into the form
of a dove's tail, and interlocking them so that they cannot be separated in the
direction of the strain without breaking the materials asunder. Sometimes a
solid piece dovetailed at each extremity is employed to connect two other
pieces or parts together, by entering morticed cavities in the latter,
DOUGH. The paste formed by kneading flour and water together in the
preparation of BREAD, which see ; also KNEADING.
DRACHM, or DRAM. A weight consisting of the sixteenth part of an
ounce avoirdupois, and the eighth of an ounce in apothecaries' weight.
DRAG SHEETS. The name given to a contrivance for lessening the drift
of vessels in heavy gales of wind, for which Mr. Burnett obtained a patent
in 1826. The current caused by the action of the wind extends but a

DIRAG SHEETS. 449
few feet below the surface, even in the heaviest gales; and if a body be sunk
to a considerable depth it will remain nearly stationary. Dr. Franklin, aware
of this fact, recommended vessels encountering adverse gales in the open
ocean, instead of lying to, to form a kind of floating anchor by attaching a
stout hauser to four bridles from the four corners of a sail, the corners being
distended by spars, and then lowering the sail into the sea with sufficient
weight to sink it. The effect of it will be considerable in retarding the pro-
Th.
Rºsssssss
ſº-ºº:
“S$º #: zº& -
gress of the vessel astern. Another well-know that any substance
floating upon the water, prevents, in a very great degree, the waves from
breaking; and fishermen and sailors who have taken to the boats upon a
vessel, frequently make them fast with some scope of rope to a spar,
which they throw overboard, which breaks the force of the waves, and allows
the boats to ride in comparatively smooth water. Mr. Burnett's invention is a
combination of these two plans, as will be perceived from the annexed repre-
sentation of it. The upper figure represents the drag sheet, viewed a little in





450 DRAINING.
perspective; a is a plank hollowed out underneath, so as to form a cavity of
sufficient dimensions to receive the remainder of the apparatus when rolled up.
When in use, this plank forms the float for the rest of the apparatus; appended
to it, and sunk in the water b, is a circular bar or rod of metal, firmly fixed at
the extremities to the float, within the cavity before mentioned; round this
bar the upper side of a square piece of sail-cloth c is fastened; the lowermost
side is in like manner secured to another metallic bar or roller d, the ex-
tremities of d are formed into rings or eyes, which are thereby hung upon
hooks attached to the uppermost bar b; a series of eye-hooks, like the one
shown in the margin (at ) sliding upon the
rods f are then employed to stretch the can-
vass c tightly out between them. The frame
thus completed, a rope or chain is attached to 2.
each corner of it; one from e to g on the one
side, and another chain in the same manner
on the opposite side; both these pass through a
ring h, as represented, which ring is attached -
to a hauser or cable, that is made fast to the bow of the ship. By this
arrangement the heaving of the vessel, or of the drag, by the undulatory
motion of the waves, allows the ring to traverse up and down the chains, pre-
serving thereby the perpendicularity of the drag, and consequently producing
the utmost resistance to its passage through the water.
DRAGON BEAMS are two strong braces, supporting a breastsummer, and
meeting each other on the shoulder of the king-post.
DRAGON'S BLOOD. A red coloured resin, imported from the East Indies.
It is insoluble in water, partially so in alcohol, but dissolves readily in oils: the
solution imparts a beautiful red stain to hot marble.
DRAINING, in Agriculture, the process of drawing off the water from
bogs, marshes, and lands liable to be flooded by excessive rains, by means of
drains or trenches cut to some depth below the surface, which drains serve to
collect the waters and convey them off to some lower level. Until the middle
of the last century little attention was paid to the draining of lands. The first
person who treated the subject systematically appears to have been Dr. J.
Anderson, of Edinburgh, who showed that the origin of swamps and morasses
lay in the waters, attracted from the atmosphere by the summits of hills and
mountains, percolating through the various porous strata of which they are
composed, until they arrive at a stratum of clay, which, being impervious to
the waters, they stagnate and accumulate, until by their increasing upward
pressure they force their way through the soil of the valleys and lowlands at
the foot of the hills, and form bogs and marshes. The principle of his system
of drainage consists in intercepting the waters in their progress below the
surface from the hills to the low grounds, by a trench running along the base
of the hill, and extending to the substratum of clay, which impedes the progress
of the water; from this trench a drain is cut, to convey the waters to the
nearest channel that will carry them away. Mr. Elkington, about the same
period, appears to have paid great attention to the subject in England, and for
various improvements which he introduced in the practice, received from Par-
liament the sum of 1000l. In cases where the top soil is of considerable depth,
and no water therefore rises into the ditch, after cutting five or six feet down,
both Mr. Elkington and Dr. Anderson recommend to bore with a proper auger
until the clay be reached, when the water will rise through the holes into the
trench. These trenches should be made narrower as they descend, by spades
of a proportionate size, but the lowest part ought to be more contracted than
any other, so that the shoulders or edges of it may support stones or faggots,
in order to cover the whole at a small expense without obstructing the currents
of water. In many places hollow bricks or ridge tiles are substituted for stones
or faggots, as being cheaper. When the land to be drained consists of a long
level tract, without sufficient fall to carry off the water from the reservoirs or
pits into which it is conveyed by the drains, or when there is a rising ground or
an embankment between the drained land and the level which is to convey the



1)RAINING.
451
water off, it must be elevated mechanically; for this purpose pumps, driven by
windmills, are very extensively employed in Lincolnshire.
Where there is
sufficient outfall, water may also be conveyed over an intervening obstacle by
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means of a syphon, provided that the height of the syphon do not much exceed
20 feet; but one objection to this method consists in the interruption to which
the action of the syphon is liable, from the extrication of the air which all

























452 DRAW BRIDGE.
common water contains, and which begins to separate from that fluid as it rises
under diminished pressure in the short leg of the syphon, till at length the
angle of the syphon is filled with air, and the current of water is interrupted.
To remove this defect, Mr. Cowen, of Carlisle, places a box at the upper angle
of the syphon, into which all the ai separated from the water rises; and the
application of a forcing pump for a few minutes once or twice a day drives the
air out of the box into the atmosphere. Fig. 1 represents Mr. Cowen's plan
applied to the draining of a quarry. a a represent a part of the quarry; b a
level lower down than the bottom of the quarry, which, in this case, is 200
yards off where the water is to be discharged; c the highest ground over which
the water is to be conducted; d, e, and f, three distinct rises, over which the
pipes pass (they are further apart than here shown); g g h h the lead pipe,
composing the two legs of the syphon ; ; a common forcing pump, fixed below
the surface of the water, having a hinge valve at j, Fig. 2, and an open working
box, with a similar valve k. These valves are opened by the force of the water
flowing through the pump in its passage to the syphon; l the working handle
of the pump; m is a close iron receiver, shown larger in Fig. 3, having inserted
at the end n the ascending leg of the syphon g, and at the other end o the
descending leg h; at the upper side of both ends are inserted two small air
pipes p p, joining with the syphon pipe at the highest bends, as shown at d, e,
and f, with a regular slope into the interior, to allow the air to ascend into it;
g is a small valve fixed at the highest point of the receiver, to allow the whole
of the air to escape through the valve when the water is forced up by the
pump; for this purpose the pump i and the pipeg must be capable of supplying
the water quicker than the pipe h will carry it off.
Directions to be observed in laying the syphon to suit different situations.—
First, in laying the pipes of the syphon, it is necessary to give them a regular
slope, to admit the air to pass forward into the receiver, or to the highest bends,
which must have either an air receiver to each bend, or a pipe inserted to
convey the air to a general receiver. Second, when sufficient descent can be
obtained on both sides from the air receiver, no air pipes will be required.
Third, in situations where it may be necessary to carry the pipes over more
tnan one elevation, and the second exceeds the height of the first, a separate
receiver will be required for each elevation. On this construction, viz. with
more than one receiver, it is necessary to adopt the following expedient for
closing the valves in succession as the air is expelled from each receiver. Fig. 4
is the lower valve in the receivers, which is opened by the force produced by
pumping, and the air escapes; t is an inverted valve, with a float v fixed upon
the valve spindle in the centre of the cup u. While the air only is expelled,
the inverted valve will remain open; but when the water is forced out and fills
the cup, the float will rise and close the valve at the same time; thus the
water being stopped from flowing out, will be forced forward to any number of
receivers in succession. w is a very small outlet pipe, inserted into the bottom
of the cup u, through which the water escapes slowly; as the cup is emptied
the float is lowered, and the inverted valve again opened—a position necessary
to allow the air to escape at the next pumping. Another method for closing
the valve is shown at Fig. 5. q is a valve placed in a cup, as shown in Fig. 1;
on the cup is mounted a lever, with a counterweight a. at the one end, and a
small pendant receiver y at the other end; 2 is a conducting tube inserted into
the edge of this cup, to convey the overflowing water into the receiver, which,
as it fills, loads the valve and prevents the escape of the water, and thus forces
it forward, as before described, to any number of receivers. The preceding
account of this valuable improvement in the art of draining, by means of the
syphon, is extracted from the original description of it by Mr. Cowen, in the
Transactions of the Society of Arts, for the communication of which the Society
awarded him the gold Vulcan medal. In the 45th volume of the Transactions
are some interesting details of his experiments.
DRAUGHT. The depth of water necessary to float a ship or other vessel.
For the draught of carriages, see Resistance. -
DRA WBRIDGE. A bridge thrown over a ditch or ravine, which may be
DRILL. 453
drawn up or let down at pleasure, one of its ends serving as an axis or joint
for that purpose, while the other is connected by means of chains to two strong
levers, called plyers, which are framed together with other timbers in the form.
of a cross, and are supported by two jambs, on which they swing. Bridges of
this kind are most common in fortresses, to cut off communication with the
surrounding country. In canal navigation, and in wet docks, swing bridges
that turn horizontally upon one end as an axis have almost wholly superseded
drawbridges.
DRIFT, in Mining, a passage dug under the earth, betwixt shaft and shaft,
or turn and turn.
DRIFT, in Navigation, the angle which the line of a ship's motion makes
with the nearest meridian, when she drives with her side to the winds and
waves, and is not governed by the power of the helm. It also implies the dis-
tance which the ship drives on that line.
DRILL. An instrument for boring holes in metals and other hard sub-
stances. It usually consists of a straight piece of steel, one end of which is
formed into an angular point, and the other into a blunted round point, for
inserting into a hole in a steel breast-plate, which is worn by the workman
whilst operating with the instrument, in order that he may steadily press the
point into the work, while he, at the same time, turns it backwards and for-
wards by means of a bow and cord, the latter being passed around a small
pulley fixed about the middle of the drill. Sometimes drills are fixed to braces
or stocks for the purpose of drilling. For boring large holes in metal, smiths
and engineers employ a very convenient arrangement of levers for applying
pressure to the drill, which is called a ji and is delineated in the sub-
joined cut. a b is a lever of the second
class, whose fulcrum is at a the weight
being applied at b, its efficacy is trans-
mitted to the point c, in a ratio propor-
tioned to the relative distances between
b c and ea. As the pressure upon the drill
often requires relieving, a lever d e is
added, whose fulcrum is at f. The ex-
tremity of the shorter arm is connected
to the lever a b by any convenient
method ; and when the workman wishes
to release the brace g, he applies his
power to the extremity of the longer arm
by pulling down at d, which raises the
shorter arm, and with it the lever a b,
consequently the brace g is at liberty to
be removed. In order that the work
may be firmly fixed, it is usual to screw
it fast between the chaps of a vice, as
shown at o l m n in the cut.
The annexed cut represents an ex-
tremely simple and ingenious contrivance for drilling holes, used by the smiths
in Ceylon. It is about two feet and a half high ; the cord attached to the
cross sticks is made of slips .
of hide twisted. Theround -
weight to give momentum is
of compact neiss, neatly cut.
Any kind of borer can be
fixed to the extremity of the
wooden rod. The instru-
ment is worked on the prin-
ciple of torsion. The hole
in the cross arms or handle,
through which the spindle
of the drill passes, is suffi-


454 I) RY ROT.
ciently large to admit of it being slided easily up and down the spindle. Upon
turning the cross a few times round the spindle, the cords become twisted in a
corresponding degree round its upper part, and upon pulling the cross down-
wards, the cords in untwisting impart a rotatory motion to the spindle, which,
by the impetus which the weight upon it acquires, is continued after the cords
have become straight; and the cross being then slided up the spindle, the cords
become twisted round it in a contrary direction; and by again depressing the
cross, the spindle revolves the reverse way.
DRILL, in Gardening and Agriculture, a small trench made in the ground,
for sowing in it the seeds of vegetables.
DRILL HARROW. A small harrow employed in drill husbandry, for
extirpating weeds, and pulverizing the earth between the rows of plants.
DRILL HUSBANDRY. A mode of cultivation in which the sowing of
seeds in drills is adopted, instead of the more common method of broad casting.
It is also called horse-hoeing husbandry, because the plants thus cultivated in
rows admit being cleansed from weeds and earthed up by a machine drawn by
one horse, and therefore called a horse-hoe. A great variety of machines are
employed in this branch of agriculture. See PLough.
DRUG. A general name of commodities brought from abroad for the pur-
poses of medicine, dyeing, tanning, and various other arts.
DRUG MILLS are machines used for triturating drugs; but as they are for
the most part applicable to the grinding of other substances, they are described
under the general head of MILLs.
DRUM. A martial musical instrument in the form of a cylinder, hollow
within, and covered at the two ends with vellum, which is stretched or slack-
ened at pleasure, by means of cords with sliding knots. The cylinders are
usually made of wood, but sometimes of brass. Kettle-drums are large basons
or hemispheres of copper or brass, covered on their flat sides with vellum,
which is fastened to the peripheries by circular rims of metal, provided with
º screws for tuning them ; they are usually played upon in
pairs, and are chiefly used in the musical bands of cavalry regiments, or in
oratorios, operas, &c.
DRUM is a term in machinery, applied to cylinders or barrels, around which
endless straps, chains or cords, are passed, to communicate motion or power to
other mechanism. When cylinders so employed are narrow in the direction of
their axes, they are usually denominated pulleys or riggers.
DRY ROT. A term applied to that rapid decay of timber by which its
substance is converted into a dry powder, which issues from minute tubular
cavities resembling the borings of worms. On the causes of this decay numerous
volumes have been written, and nostrums for its prevention or “cure” have
been proposed without number, yet the dry rot continues to ravage our houses,
and to destroy our ships. It has been said that moist and warm situations,
where the circulation of the air is impeded, is the generating cause of this
disease, and that the effluvia from timber so diseased will carry its effects to
the circumjacent timber; and that any sort of wood, dry as well as damp, so
exposed, will be soon destroyed. Timber once infected cannot be restored,
and the only remedy lies in cutting away the diseased parts, to prevent the
extension of the evil to the remainder; and to effect even the latter a free
circulation of air must be admitted, and the parts be washed over with a strong
solution of iron, copper, or zinc. Patents have been granted for various
applications of the latter, as preventives of the dry rot, the distinguishing
features of the processes therein employed consisting in first preparing the
timber by a good steaming, or drying out of the sap, and afterwards injecting,
soaking, or boiling the timber in a solution of copperas, or other º: salt.
The following observations on this important subject were some time since
addressed to the editor by Mr. John Gregory, who is an experienced and
observant shipwright; and as they appear to mark out clearly the true cause
of, and to suggest a very simple remedy for, the evil, it is right to give them a
place in this work. Mr. Grégory says, “Instead of squaring a piece of timber
according to the usual method, by leaving the heart of the tree in the centre.
DRY ROT. 455
my plan is to saw it right down the middle, through the heart, into two equal
parts, immediately after the tree is felled; and my reasons for this I will now
endeavour to explain to the best of my ability. It is, I believe, a well-known
fact, that a tree does not, literally speaking, die on receiving the final stroke of
the axe, but that it continues for a i. period afterwards to vegetate, though
less vigorously. At length, however, the sap ceases to circulate, the pores
become closed, and the juices of the tree thus shut up undergo decomposition,
and lay the foundation of dry rot. It is well known that a man who dies in a
full habit of body soon decays; the same effect takes place in a tree full of sap,
unless we adopt the same method with respect to it as the Egyptians practised
with the human body, viz. that of depriving it of all moisture, which process
would give to our timber a durability almost everlasting. My mind has been
long impressed with this idea, which has been confirmed by my having recently
noticed that several of the timbers in a very ancient public building, which had
been sawn originally in the manner I have proposed, were perfectly sound,
although they had withstood the dilapidating hand of time for seven hundred
years; while other timbers in the same building, which had not been so cut,
but apparently squared out with the heart in the centre, were perfectly rotten.
That the dry rot is certainly caused by the juices being enclosed in the heart of
the timber, I have had frequent opportunities of observing during my long
practical experience in the repairing of ships. In the frame of a ship in which
such large quantities of timber are employed, I have uniformly noticed, First,
that the decay commences in the run fore and aft, which is owing to the timbers
being fitted so close together at the heels or lower ends. The evil being thus
enclosed in the hearts of the timbers, and the air having no access to the
exterior of them to carry off the moisture by evaporation, internal decay is the
necessary consequence. I have sometimes witnessed these parts of the frame
of a ship in such a rotten state as to have been justly compared by the workmen
to a heap of manure. Secondly, those timbers in the midships that have been
bored off with the outside planks are not so affected, which I attribute to the
circumstance of the holes admitting a current of air through them, the destructive
juices being thereby carried off. Thirdly, it frequently happens that the floor
timbers of an old ship are found, on breaking up, to be nearly as sound as they
were when first put in. Their preservation seems to be owing to the effect of
the salt water which constantly laves over them, causing them to become in a
manner pickled; or it may be, that the salt entering into the composition of the
wood, the destructive effects of its natural juices are thereby prevented. Fourthly,
the planks in the bottom, nearest to the timbers, take the infection first ; , and
where the tree-nails are not close, the disease rapidly extends endways of the
grain. Fifthly, those parts of the deck planks that lie upon the beams are
those which are first infected with the rot, the cause of which is evident, as
those parts that are between the beams are generally quite sound. Sixthly, in
the beams of ships the decay usually commences in the internal parts, which is
decidedly owing, in my opinion, to the erroneous method of preparing the
timber, as before mentioned; but when timber, so prepared, is used, I would
recommend, as the best preventive of the rot, that a few holes be bored through
the beam fore and aft, and, what would still add to the benefit, to bore another
hole lengthways of the grain, to meet those which are bored crossways. . But
the best preventive, I am confident, would be the adoption of my mode of
preparing the timber, namely, to saw it lengthways right through the heart, by
which not only much greater durability would be obtained,
but great economy in the consumption of the timber, as well
as a great increase of strength, which I will proceed to ex-
plain by reference to the annexed figure, which exhibits an
end view or section of a piece of timber. Having procured
a log of the shape required, first cut off the two slabs b b,
and then divide the remainder a a into two equal parts.
Being thus sawn through the heart, the air will rapidly
absorb the juices, and such a seasoning may be soon effected
as will, I have no doubt, completely prevent the dry rot. But my object in

456 DRY ROT.
this place is to show the economy of the plan in a mechanical point of view. By
thus sawing a log through the middle, two timbers are immediately provided
instead of one, and both of one precise mould. Thus when the pieces a a in
the above figure are placed end to end, they will form two timbers exactly
similar, as appears by the annexed figure. The expedition gained by this
method of converting timber is
obvious; every ship-builder is
fully sensible of the difficulty
he is often put to, and of the Q, Q,
sad waste of time and labour -
often incurred in preparing two
such timbers to match one another. It not unfrequently happens that the
framing of a ship stands still for several days owing to this circumstance. The
saving of time and labour is in consequence an important saving in the expense
of building. I have also proved by experiment that this mode of sawing the
timber down the middle confers great additional strength. From the same
bough I cut two pieces of the same length and thickness; one of them I squared
according to the usual plan, which I condemn, the other, according to my pre-
posed method, leaving the circular sides, as shown at a a in the foregoing
figures. The proportional strength of only one of the pieces I found to be as
25 compared to 27, the strength of the whole square timber; the strength of
the two pieces, therefore, makes the difference of 50 to 27, or nearly double;
in addition to which advantage, far greater durability will be obtained by the
prevention of the dry rot. For the timbers of a 74-gun ship, logs of 22 inches
diameter are usually employed; if these, instead of being squared, are divided
according to my method, their strength and width of bearings for the planks
will be fully adequate, and the little difference of strength may be easily com-
pensated by two or three more timbers, for which there will be plenty of room,
and the saving of expense will thereby be immense. By the most accurate
calculations that I have been enabled to make, I find the saving in timber only
to be full one-third. The annexed sketch represents a horizontal section of
a small portion of a ship's side, with
the arrangement of the timbers accor-
ding to my plan, a a a, three of the
ship's timbers; b b b b, the fittings
made from the slabs before mentioned,
which are uniformly of a suitable
shape; c c are air passages, which
serve effectually to carry off whatever
moisture may remain in the timber,
the hearts of the trees being exposed to the air. It will likewise be perceived
that the circular form of the grain being retained, the strength of the timber
is better preserved than if the logs were squared, as I have proved by the
before-mentioned experiment. From long observation and repeated investigation
I am indeed convinced that the outside, or younger part of a tree, is stronger,
more durable, and more seaworthy, than the heart, notwithstanding I have
daily witnessed the preference given to the latter, while the former has been
used for fuel. In the repairing and breaking up of ships, it will be almost
invariably found that the decayed planks have the heart of the tree, and the
sound ones, not; it follows, therefore, that the present system of lining is very
defective. To lessen the charge of carriage, it is not unusual to side the logs
where the trees are felled. Now, if the trees were also sawn down the middle
in the forest, an increased facility of removal would be acquired, and the
timber would be seasoning, and probably be fit for use, ere it came into the
dock-yard. The longer a tree remains whole after it is felled, the more sap it
will contain, and the more rapid will be its decay. I have seen many trees
that were sound when felled, decay from the heart outwards, owing to their
lying a long time with their juices shut up in them. The dividing of the trees
would have preserved them.”
DUCTILITY. That property or texture of bodies which renders it prac-

DYING. 457
ticable to draw them out in length, while their thickness is diminished,
without any actual fracture of their parts. -
DULCIFICATION, or DULcERATION, in Chemistry, the combination of
mineral acids with alcohol, by which their caustic or corrosive qualities are
diminished : thus we have dulcified spirit of nitre, dulcified spirit of
vitriol, &c.
DULCIMER. A musical instrument, strung with about fifty wires, cast over
a bridge at each end. It is performed upon by striking the wires with little
iron rods. -
DUODECIMALS, or CRoss MULTIPLICATION, is a rule used by workmen
and artificers in computing their work. Dimensions are usually taken in feet,
inches, and parts, omitting all those which are less than one quarter of an inch
as of no consequence. Rule:—Set down the two dimensions to be multiplied
together one under the other, in such manner, that feet shall stand under feet,
inches under inches, and parts under parts; then multiply each term in the
multiplicand, beginning with the lowest, by the feet in the multiplier, and set the
result of each directly under its respective term, observing to carry one for
every 12 from the parts to the inches, and from the inches to the feet. In like
manner multiply all the multiplicand by the inches and parts of the multiplier,
and set the result of each in one place, removed to the right hand of those in
the multiplicand, and the sum of these successive products will be the answer.
Ewample. Multiply 6 feet 4 inches 3 parts by 10 feet 3 inches 9 parts.
ft. in. pts.
6 4 3
10 3 9
63 6 6
1 7 0 9
9 2 3
3
Answer . . 65 6
It should be observed, that the feet in the answer are square feet, but the
numbers standing in the place of inches are not square inches, as might at first
be supposed, but twelfth parts of square feet, each part being equal to twelve
square inches. In like manner the number standing in the place of parts, or
in the third place of figures, are so many parts of the preceding denomination;
these, therefore, are square inches.
DYING. The art of tinging or imbuing various substances with different
colours at pleasure. The principal application of this art is to fabrics of wool,
silk, and cotton; but it is also applied to the colouring of leather, marble,
ivory, and various other substances. We shall limit our description to the process
of dying the first-mentioned substances. The simple colours employed in
dying are mostly either of animal or vegetable origin; but although the
number of possible dyes which might be obtained from these sources is almost
infinite, the number employed in the regular manufactories of Europe is small,
the infinite diversity of tint which is obtained being the result of the combi-
nation of two or more simple colouring substances with one another, or with
certain chemical reagents. Of the great variety of known dyes, some (though
comparatively few) may be applied to animal or vegetable stuffs without any
other preparation than that of cleansing the stuff, and then immersing them in
a decoction or infusion of the dye, which then becomes so permanently com-
bined with the fibre as to resist the effect of washing and the bleaching power
of the sun and air. But the greater number of dyes have such feeble affinity
for fibre that no permanent combination can be effected between them in their
simple state; to effect the combination, recourse is had to various substances
having a strong affinity both for the fibre and the colouring matter; and the
cloth being previously steeped in a solution of some of these substances, and
afterwards immersed in the dye, an intimate union of the cloth and the colour-
458 DYING.
ing mattter is effected. The substances which serve to fix the colouring
matter in the cloth are termed mordants; and in the management and selection
of them is the chief art of the dyer, as their effects are not limited to the fixing
of the colour, but they, in most cases, produce some alteration in the natural
hue, a circumstance which the dyer avails himself of in numerous cases, to
vary and improve the colour obtained from simple dye stuffs: thus aluminous
mordant changes the dull red of madder to a bright crimson; and the solutions
of tin not only fix cochineal in wool, but change it from crimson to bright
scarlet; but if the oxide of iron be substituted for the tin as a mordant, the
colour becomes changed to a black. In dying, then, it is necessary not only
to procure a mordant for the colouring matter and the cloth, and a colouring
matter which passes the desired colour in perfection, but to procure a mordant
and colouring matter, which, when combined, shall produce the colour sought.
It is also evident that a great variety of colours may be produced from a single
dye stuff, provided the mordants can be sufficiently varied. Mordants are
generally composed of earths or metallic oxides, tannin, and oil. Of earthy
mordants, the most important and generally used is alumine, either in the state
of common alum, in which it is combined with sulphuric acid, or in that of
acetate of alumina, which answers much better than alum, as the cloth is more
easily saturated with alumine, and takes, in consequence, a richer and more
permanent colour. Almost all the metallic oxides have an affinity for cloth,
but only two of them are extensively used as mordants, viz. the oxides of tin
and of iron. The oxide of tin was first introduced in dying by Kuster, a
German chemist, who brought the secret to London in 1543. It is generall
employed in the state of nitro-muriate, muriate, or acetate of tin. Iron is
generally employed in the state of the sulphate or the acetate; the first being
chiefly used for wool, and the latter for cotton. Tannin has a very strong
affinity for cloth, and for several colouring matters. It is principally obtained
from nut galls, or sumach, which contain it in great quantities. Tannin is also
often employed along with other mordants to produce a compound mordant.
Oil is also used for the same purpose in dying cotton and linen. We now pro-
ceed to a consideration of the dyes, and commence by observing that innumer-
able as are the different colours and shades of 'colours communicated, they all
originate from four or five primary dyes, modified according to the colour
intended to be produced. These primary or simple dyes are as follow :—blue,
yellow, red, black, and fawn, or brown colour.
Of Blue.—The only two substances used for dying blue are woad and indigo.
Indigo has a very strong affinity for wool, silk, cotton, and linen, all of which may
therefore be dyed with it without the assistance of any mordant. But indigo
is soluble only in sulphuric acid; it is therefore necessary either to employ the
sulphate of indigo, or to render it soluble in water, by depriving it of its
oxygen. The first process is frequently employed for dying wool or silk; but for
linen or cotton, the latter is generally resorted to. When the sulphate is em
ployed, one part of indigo is to be dissolved in four parts of concentrated sul-
phuric acid, and one part of dry carbonate of potash added to the solution,
which is then to be diluted with eight times its weight of water. The cloth
must be boiled for an hour in a solution of five parts of alum and three of
tartar, after which it must be removed to a bath containing a greater or smaller
proportion of the sulphate of indigo, according to the shade which the cloth is to
receive; and in this bath it must be boiled until it acquire the desired colour. The
alum and tartar are not intended to act as mordants, but to facilitate the decom-
position of the sulphate of indigo. The alkali added to the sulphate answers
the same purpose. But the most common method of employing indigo is to
deprive it of the oxygen to which it owes its blue colour, and thus reduce it
to the state of green pollen, and then to dissolve it in water by means of
alkalies or alkaline earths, which act very readily upon it in that state. It is
deprived of oxygen either by admixture with other substances possessing a
greater affinity for oxygen, as the green oxide of iron, or various metallic
sulphurets; or it may be mixed in water with certain vegetable substances
which readily undergo fermentation: the ferments most commonly employed
DYING, 459
are woad and bran. During this fermentation, the indigo is deprived of
its oxygen, and is then dissolved by means of quicklime or alkali added to the
solution. The first of these methods is usually followed in dying cotton or
linen; the second, in º wool and silk.
Of Yellow.—This colour is most commonly obtained from weld, fustic, or
quercitron bark. The cloth requires to be º: before dying, by com-
bining it with some mordant; that most commonly employed for this purpose
is alumina.
Of Red.—The materials employed for this colour are lac or kermes, cochi-
neal, archil, madder, carthamus, and Brazil wood; and the ordinary Inordants
are alumina, and the oxides of tin; various shades are produced by intermix-
ture of the dying materials above named, or by first dying the stuff with one
or more of them, and subsequently passing it through a yellow bath.
Of Black.-The substances employed to give a black colour are red oxide of
iron and tannin. These two substances have a strong affinity to each other,
and, when combined, assume a deep black colour, not liable to be decomposed
by light. Logwood is usually employed as an auxiliary, because it commu-
nicates lustre, and adds considerably to the fulness of the black, Cloth, before
it receives a black colour, is usually dyed blue, which renders the colour much
fuller than it would otherwise be; for inferior cloth, a brown colour is some-
times given by means of walnut peel.
Of Brown, or Fawn Colour.—Various plentiful and cheap substances are
employed to give a brown or fawn coloured ground, as birch, sumach, alder
bark, but more especially decoction of walnut peels, or walnut bark or root.
The shades produced by the bark or rind of the walnut tree are particularly
fine, the colours solid, and it renders the wool, when dyed in it, flexible and
soft. From the above colours variously combined are derived the endless
gradations of tint imparted to the various fabrics of silk, wool, cotton, and
linen. Of these compound colours we shall notice a few of the principal.
Of Green.—This is a mixture of blue and yellow, the shade varying accord-
ing to the prevalence of either ingredient. . The cloth is generally first dyed
blue, and then immersed in a yellow bath; but when sulphate of indigo is
employed, it is usual to mix the ingredients together, and dye the cloth at once.
Of Violet, Purple, and Lilac.—These are all mixtures of blue and red, and
depend upon the different shade produced by the proportion of one colour to
the other. Wool, cotton, and linen, are first dyed blue; the two last are then
galled, and soaked in a decoction of logwood, or of green sulphate of iron ;
they are then dyed scarlet in the usual manner : by means, however, of
cochineal, mixed with sulphate of indigo, the process may be performed at
once. Silk is first dyed crimson with cochineal, and then dipped in the indigo vat.
Of Orange.—This is a mixture of yellow and red. . A remarkable differ-
ence exists in the affinity of various substances for colouring matter, animal
substances generally taking the dye much more readily than those of vegetable
composition—thus wool and silk are more easily dyed than cotton and linen;
the latter article, indeed, has so slight an affinity for the dye that it is extremely
difficult to impart to it a bright and permanent colour. The processes and
manipulations in dying are few and simple, and require principally a good eye
to judge accurately of the gradations of the tints, and care and attention in pre-
paring the ingredients, and in maintaining the baths at a proper temperature.
Mr. J. Hall, of Ordsall, near Manchester, has recently obtained a patent for
an apparatus, shown in the engraving on the following page, the object of
which is to cause the goods to be exposed to the action of the liquor in
the dye vat in a more equal manner than is done in the ordinary method. In
the dye vat a are placed six small rollers, 1 to 6, one at each corner, and two
near the middle, on the same line with 1 and 4. At about half the depth of
the vat are placed two large rollers b and c, about one foot asunder; one end
of each of the axes of these rollers comes through a stuffing-box, and on the
axis of b is placed a cog-wheel, which is connected with the axis by a pin
passing through it that can be withdrawn at pleasure; on the axis of c is a
similar wheel gearing into b, and may be thrown out of gear when required by
460 DYNAMICS.
the lever d. On the top of the vat is the roller e, whose axis turns in bearings
fixed in each side of the vats; and upon this roller another roller frests, which
can only move in a vertical direction, its axis being square, and confined by
guides g. At one end of the vat is a roller h, supported in two upright forks,
and having a small wheel on its axis; another wheel k on a short axis is placed
between the last mentioned wheel and the wheel and the axis of c, and gears
into each. The roller h may be lifted out of the forks by the lever l. To the
roller c is fastened a piece of cloth of the width of the goods to be dyed; this
cloth passes over the rollers 6 and 1, under 2 and 3, and over 4: a similar
w N - |i – - Al
Nº º tº
…N.
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:
º
||||||||||||||||{:};
*, *
ºr
... * º º
| | |ſiſ | =
f
|º . . . ſº * i;
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É
piece of cloth is wound round the roller b, the end of which is brought up and
hung over the roller 5. The cloth or web to be dyed is attached by a long
skewer to the cloth of c, hanging over the roller 4: the wheel b being now
unpinned, and set in motion by a band wheel, or other means, the web is
wound upon c, passing under the roller, as before described, until the outer end
arrives at the roller 4, when it is attached to the cloth of b by a skewer, and
the wheel turned until the cloth on b is unwound. The wheel on c is next
thrown out of gear, and that on the axis of b is pinned to its axis, when the
wheel being again set in motion, the cloth is unwound from c and wound
upon b ; and it is thus wound alternately upon each of the rollers b and c, until
it is deemed sufficiently dyed. It must then be wound upon the roller b, and
the cloth, being detached from the web c, is passed between the rollers e and
f, and made fast to the roller h. The wheel on b is then unpinned, and being
set in motion, turns h by means of the wheel on c, and the small wheel k; the
piece is thus wound upon the roller h, and deprived of a great portion of mois-
ture by the pressure of the rollers ef. When the end appears above the roller
5, the skewer attaching it to the cloth of b is withdrawn, and the roller h is
lifted out of the forks by the lever l, and replaced by a similar one.
DYNAMICS treats of the nature and laws of motion. In this sense it is
used in opposition to STATIcs. A single force, always producing motion, must
be considered under the head of Dynamics; but two or more forces, accordingly































































































ſ)Y NAMOMETER. 461
as they result in producing motion or not, constitute cases in StAT1cs or
DYNAMIcs. These two terms are frequently used to designate the two great
divisions of mechanics—Statics, including all cases where equilibrium is pro-
duced, and Dynamics, those in which motion results. The term dynamics is,
however, not confined exclusively to the motions of solid bodies. When applied
to describe the laws of motion in fluids, it is termed hydrodynamics, and electro-
dynamics when used to comprehend the phenomena of electricity in motion.
See Forces, Motion, &c.
DYNAMOMETER. An instrument employed to measure the comparative
strengths of men and cattle, and to ascertain the force required in drawing
r: A:

462 EAR TRUMPET.
carriages upon land, and vessels upon canals. These effects are usually esti-
mated by the compression or distension of a strong spring, or by a steelyard
upon the principle of a bent lever balance; but in both these constructions the
instrument is subject to great vibration, owing to inequalities in the resistance
and in the moving force, which render the indications very uncertain. This
objection to spring dynamometers has been obviated by Mr. H. R. Palmer, as
follows:—a piston, fitting loosely in a cylinder filled with oil, so as to allow the
oil to escape slowly past its sides as it moves up and down, is connected with
the springs by means of a fine steel wire passing through stuffing boxes at each
end of the cylinder; the friction, therefore, is so extremely slight as not to be
worth taking into account in any experiments, whilst it prevents that vibratory
motion of the index, from jerks, and allows the resistance to be ascertained
with the greatest accuracy. The preceding engraving is a representation of the
instrument. a a represents the back of the dial plate of any ordinary spring
weighing machine, the front of which is shown separate in Fig. 2 (but without
the graduated scale, as being unnecessary); bb are two spiral springs enclosed
in cylindrical cases, (similar to the well-known domestic article called pocket
steelyards,) the upper ends of which are fixed to a sliding frame c c, and at
their lower ends they are hooked to a cross bar f which bar is made fast to a
piece of metal 0 at the back of a a ; d is the cylinder of oil, which is firmly
fixed at the back of a a ; to this cylinder is fixed four pieces of metal e e e e,
having angular grooves, in which the frame c c slides when the springs are acted
upon. The piston in the cylinder is shown by dots, the rod to which (a fine
steel wire) passes through stuffing boxes at each end of the cylinder, and each
end of the rod is then made fast to the frame c c. Now the barg, which pro-
ceeds from the circular box a a, and acts upon the spring, is connected at the
swivel ring i with the upper end of the frame c c, as one solid piece; therefore
when the ring k is made fast to a carriage, and power applied to the rope at i,
the barg is drawn out of a, while the frame c c acts simultaneously upon the
steelyard springs c c, which move along with them the piston in the fixed
cylinder d, the oil therein being incompressible, is compelled to pass from one
side of the piston to the other, through the extremely narrow interstice between
the periphery and the cylinder.
In the dynamometer invented by Mr. Milne, of Edinburgh, an iron plunger
is by the force exerted in traction caused to descend in an open vessel con-
taining mercury, by which means the latter rises to a height indicated by a
glass tube open at top, and connected to the mercurial vessel at bottom by a
neck, the bore of which is contracted to diminish the vibrations of the mercurial
column; half the height in inches of the mercury in the tube multiplied by the
area of the base of the plunger in inches will be the amount of the force of
traction in pounds.
E.
EARTHS. A name commonly assigned to a class of solid substances com-
posing, in various states of combination, the crust of the globe; the general
qualities of which are, that they are incombustible, not convertible into metals
by the ordinary methods of reduction, and their specific gravity not exceeding
five times that of water. The number of these substances is ten; viz. barytes,
strontites, lime, magnesia, alumina, or clay, silica, glucina, zerconia, yttria,
and thorina. But although these substances are generally termed earths, the
experiments of Sir H. Davy have shown that a portion of them, viz., barytes,
strontites, and lime, as well as the alkalies, potash and soda, are, in reality,
combinations of metallic bases with oxygen and lead, and determine, by
most probable analogies, that the whole of them belong to the metallic class.
EARTHEN WARE. Articles made of baked or vitrified earth. See
Port eity.
EAlt TRUMPET. A contrivance for the benefit of deaf persons; as
usually constructed, it resembles in shape a marine speaking trumpet, but
smaller, seldom exceeding six or eight inches in length. The party using the
EBONY. 463
trumpet inserts the small end within his ear, and the speaker applies his mouth
to the wide end. Dr. Morrison, of Aberdeen, however, contends that this con-
struction is erroneous, and that the end which is applied to the ear should
be large enough to include the whole ear, instead of being inserted within
it. The Doctor states, that having laboured under a deafness for a number
of years, he applied in every quarter for the most improved ear trumpet;
but from none of them could he derive the most trivial benefit. He at length
ordered one to be made of the finest block tin, constructed as above recom-
mended, and found it to answer beyond his most sanguine hopes. The annexed
cut is a representation of a flexible ear trumpet, invented by Mr. T. Hancock,
of Fulham. It is made of Indian rubber, covered with a net-work of gold or
silver wire, and, from its flexibility, is rendered more convenient for portability
and for ready application in any situation that may be required. Mr. Hancock
has successfully applied tubes of this description as speaking pipes, to commu-
nicate verbally with the various parts of an extensive manufactory.
EASEL. A frame used by painters for supporting their pictures while in
progress, and ...; of being adjusted to any convenient angle by means
of a movable prop at the back.
EAU-DE-LUCE. A volatile preparation, which is thus made :-12 grains
of white soap are dissolved in 4 ounces of spirit of wine; this solution being
strained, a drachm of rectified oil of amber is added, and the whole filtered.
Afterwards, some strong volatile spirit of sal ammonia is to be mixed with the
solution.
EAU-DE-COLOGNE. A celebrated odoriferous liqueur: the following is
the true mode of preparing it. Take of the essence of bergamot, lemon peel,
lavender, and orange flower, of each 1 ounce; essence of cinnamon, half an
ounce ; spirit of rosemary, and of the spirituous water of melisse, each 15
ounces; strong alcohol, 73 pints. Mix the whole together, and let the mixture
stand for the space of a fortnight; after which introduce it into a glass retort,
the body of which is immersed in boiling water, contained in a vessel placed
over a lamp, while the beak is introduced into a large glass reservoir well
luted. By keeping the water to the boiling point, the mixture in the retort
will distill over into the reservoir, which should be covered with wet cloths.
In this manner will be obtained pure eau-de-Cologne.
EAVES. The edge or margin of the roof of ºil, which projects beyond
the walls to throw off the water therefrom.
EBONY. An exceedingly hard and heavy wood, susceptible of a fine polish.
There are many kinds of ebony; the most usual are the black, red, and green,
all of them the product of the island of Madagascar. The black ebony is pre-
ferred to that of any other colour, but it is not so much in request as formerly,
since the discovery of so many ways of giving other hard woods a black colour.
This may be done by boiling smooth, clean box wood in oil till it becomes per-
fectly black; or by washing pear wood with aquafortis, and drying it in a

*464 EFFECT
shady place in the open air; after which common writing ink should be
repeatedly passed over it, and the wood dried in a similar manner till it acquire
a deep black colour. It may then be polished with wax and a woollen cloth,
which will give it a fine lustre. An excellent black is also produced by first
applying a solution of copper and aquafortis, and afterwards brushing the wood
over with a decoction of logwood. &
ECCENTRIC, in Geometry, denotes two circles or spheres, one of which is
contained within the other, but the centres of the two do not coincide. In
mechanics, the name is given to a contrivance frequently substituted for a
crank, for obtaining a reciprocating motion from a circular. It consists of a
circular disc placed eccentrically upon a shaft, and revolving within a hoop
formed at one end of the connecting rod. The valves of most steam engines
which work with a fly-wheel are moved by an eccentric.
EDGE TOOLS is a general name applied to the coarser kinds of cutting
instruments, such as chisels, axes, adzes, gouges, augers, saws, &c.
EFFECT (Useful.), in Mechanics; the measure of the real power of any
machine, after deducting that portion which is lost or expended in overcoming
the inertia and friction of the moving parts, and in giving them the required
velocity, and every other source of loss. The greatest useful effect which a
horse can produce, was estimated by Bolton and Watt at 33,000 lbs. raised one
foot high per minute; and upon the introduction of the steam engine to per-
form the labour which was before performed by horses, their power was ex-
pressed by that of the number of horses which they were equal to ; and from
the convenience of this mode of expression, it has since been generally adopted
to express the power of all kinds of machinery. . It is at all times desirable to
know the real effective power of any machine: when water is to be raised, the
effect is readily computed, but in most other species of work it is difficult to
estimate the resistance, and consequently whether the engine be really equal to
its nominal power; in this case, Mr. Tredgold observes, the most convenient
and simple mode of measuring the effect is by friction. If the rim of a brake
wheel of known diameter upon an engine shaft be pressed with a force pro-
ducing a known degree of friction, which is exactly equal to the effect of the
engine at its working speed, then it is clear that if the friction this pressure
produces be ascertained, the power of the engine will be equal to the friction
multiplied by the velocity of the rubbing surface. To apply this, let A B be a
lever with a friction strap, that may be tightened upon the cylindrical surface
of the shaft or wheel C, and let it be tightened by the screw at B (the lever
being stopped by the stop at D), till the friction be equal to the power of the
engine when all other work is thrown off; then while the engine is still in
motion, add such a weight at E as retains the lever in a horizontal position.
D&
A DT - T —iºn
YS
N -
E
o calculate the power, multiply together the length of the lever FC in feet,
the weight E in lbs. the number of revolutions of C per minute, and the
number 6.2832; the result will be the number of pounds raised one foot per
minute, and divided by 33,000 it is the horses' power. Thus if a shaft make
20 revolutions per minute, and the length EC of the lever be 10 feet, and if it
be found that a weight of 240 lbs. is sufficiel,t to retain the lever in a hori-
zontal position, then 6.2832 × 10 x 240 x 25–376992 lbs. raised one foot high,
or nearly eleven and a half horses' power


ELECTRICITY. 4 G3
EFFERVESCENCE. The commotion produced in fluids by some part of
the mass taking suddenly the elastic form, and escaping rapidly in numerous
bubbles.
EFFLORESCENCE. The effect which takes place when bodies spon-
taneously become converted into a dry powder. It is almost always occasioned
by the loss of the water of crystallization in saline bodies.
EGGS. The envelope which contains the foetus of various animals, and
which, being voided by the parent, is subsequently matured by incubation.
This may also be effected by means of prolonged artificial heat; and in Egypt
the art of hatching chickens by means of ovens has long been practised, but
it is there only known to the inhabitants of a single village, named Berme,
and to those that live at a small distance from it. Towards the beginning of
autumn they scatter themselves all over the country, where each person among
them is ready to undertake the management of an oven, each of which is of a
different size, but in general they are capable of containing from forty to four-
score thousand eggs. The number of these ovens placed up and down the
country is about 380, and they usually keep them working for about six months;
as, therefore, each brood takes up in an oven, as under a hen, only twenty-one
days, it is easy in every one of them to hatch eight different broods of chickens.
Every Bermean is under the obligation of delivering to the person who entrusts
him with an oven, only two-thirds of as many chickens as there have been eggs
put under his care; and he is a gainer by this bargain, as more than two-thirds
of the eggs usually produce chickens. In order to make a calculation of the
number of chickens yearly so hatched in Egypt, it has been supposed that only
two-thirds of the eggs are hatched, and that each brood consists of at least
30,000 chickens; and thus it would appear that the ovens of Egypt give life
yearly to at least 92,640,000 of these animals. As it is of great importance
in a zoological, and, to a certain extent, even in an economical point of view,
to be able to transport eggs fresh from one country to another, it has been
proposed, as the best method of effecting this, to varnish them with gum
arabic, and then imbed them in pounded charcoal, which being a non-conductor
of heat, a uniform temperature will be preserved.
ELAINE. The oily principle of solid fats, the remaining or solid portion
being named stearine,—names assigned to these substances by the discoverer,
Mr. Chevreul. If tallow be squeezed between the folds of porous paper, the
elaine soaks into it, whilst the stearine remains. The paper being then soaked
in water and pressed, yields up its oily impregnation. Elaine has very much
the appearance and properties of vegetable oil, and is liquid at the temperature of
60°. Cocoa nut oil, which in England usually is concrete, or at most semi-fluid,
has of late years been resolved into the above-named constituents by mechanical
pressure, and the solid part manufactured into candles, whilst the liquid forms
a valuable oil for lamps See FAT.
ELASTICITY. A property of bodies to resume their form upon the removal
of any force by which they may have been deflected from it. In this respect all
bodies which come within our knowledge are comprehended under one of these
three distinctions. If two bodies, when pressed together, suffer an alteration
in their form, and if afterwards, on removing that pressure, they recover their
original figures, they are called elastic; if, when pressed, their forms are not in
the least altered, they are called hard; and if, when pressed as above, they alter
their forms, and retain the same after the pressure is discontinued, they are
called soft; and both these last kinds of bodies are termed non-elastics. It is
doubtful, however, whether any bodies are either perfectly hard, or soft, or elastic,
—the air not being perfectly elastic, and water (which was for a long time held to
be perfectly incompressible and non-elastic,) being in the opinion of many
persons shown to be compressible, by the experiments of Canton and of Perkins.
ELECTRICITY. The name assigned to a certain mysterious natural
principle or element, with the nature of which we are totally unacquainted,
as it can only be inferred from its effects, in which respect it resembles
the principles of light, heat, and magnetism. For a brief outline of the science
of electricity, see CHEXIIst Ry.
466 EMERY.
ELEMENTS. The name assigned by the ancients to those simple substances
of which, by combination, all bodies were supposed to be formed. These
principles were supposed to be four in number, viz. fire, water, earth, and
air; but the researches of modern chemistry have completely overturned this
classification, showing that each of these supposed elements is in reality
composed of two or more substances, and extending the number of simple sub-
stances to nearly fifty; at the same time it is to be observed that these sub-
stances are not pronounced to be absolutely simple, but are merely so in respect
to the present state of the art of analyzing bodies. For a list of the simple
or undecompound substances, see CHEMISTRY.
ELEVATION, in the art of design, an orthographic projection of the vertical
figure of any building or piece of machinery, there being no vanishing points,
as in a perspective representation, but the eye being supposed to occupy the
whole space of the picture, or every part of the object being deemed perpen-
dicular to the eye.
ELIQUATION. An operation by which one substance is separated from
another that is less fusible. It consists in the application of a degree of heat
sufficient to fuse the former, but not the latter.
ELIX1R. A compound tincture extracted from many ingredients, whereas,
a simple tincture is extracted from only one ingredient.
ELLIPSIS, in Geometry, a curve line returning into itself, and produced
from the section of a cone by a plane cutting both its sides, but oblique to the
axis of the cone.
EMBOLUS. Any thing inserted and acting in another, as the sucker of a
pump, the piston of a steam engine, &c.
EMBOSSING. The forming of ornaments in relief upon any substances,
whether by sculpture, casting, stamping, or any other means. One pleasing
species of embossing is that by which the leather covers of books are now so
richly ornamented; this is effected by means of a metal plate on which the
pattern is engraved, and which, being heated, gives the impression to the
leather by the action of a powerful fly-press. The following method of em-
bossing on wood, invented by Mr. Straker, is extracted from the Transactions
of the Society of Arts; it may be used either by itself, or in aid of carving, and
depends on the fact, that, if a depression be made by a blunt instrument on the
surface of wood, such depressed part will again rise to its original level by
subsequent immersion in water. The wood to be ornamented having first been
worked out to its proper shape, is in a state to receive the drawing of the
pattern; this being put in, a blunt steel tool, or burnisher, or die, is to be
applied successively to all those parts of the pattern intended to be in relief,
and at the same time is to be driven very cautiously without breaking the grains
of the wood, till the depth of the depression is equal to the subsequent pro-
minence of the figures. The ground is then to be reduced by planing or filing
to the level of the depressed part; after which the piece of wood being placed
in water, either hot or cold, the parts previously depressed will rise to their
former height, and will thus form an embossed pattern, which may be finished
by the usual operation of carving.
EMBROIDERY. The enriching of cloth, stuff, or muslin, by figures worked
thereon with a needle, with thread of gold, silver, silk, or cotton. The em-
broidery of stuffs is performed in a kind of loom; that of muslim by stretching
it on a pattern already designed, and the thinner the muslin the better it is
adapted to the purpose.
EMERALD. A well-known gem, of a pure green colour, somewhat hard. r
than quartz, though softer than most of the precious stones. Owing to the
beauty of its colour, and the fine contrast it makes with brilliants, it is valued
next to the ruby. The oriental emerald is considered to be a variety of ruby of
a green colour.
EMERY. A very hard mineral, of a dark grey colour. The best is
9btained from the island of Naxos, whence it is imported into this country; it
is found in irregular masses, mixed with other minerals. It is so hard as to
scratch topaz. §. constituents are 86 alumina, 3 silicia, 4 iron, and 7 loss. Its
ENAMEL. 467
specific gravity is 4.0. Emery is also obtained from some of the iron mines in
this country. The extreme hardness of this substance has caused it to be
employed in various arts. , Lapidaries employ it in cutting and polishing of
precious stones; opticians, in grinding glass preparatory to polishing. It is very
extensively used by the manufacturers of iron and steel wares; is a common
household material for brightening iron ; and is applicable as a grinding,
scouring, and polishing powder, in a great variety of operations. For all these
purposes it is first pulverized in large iron mortars, and the powder, which is
very sharp, is frequently washed to free it from foreign matters; it is then dried,
and afterwards sifted into six or more different degrees of fineness, for the
various purposes before mentioned.
EMPYREUMA. A term implying a peculiar odour derived from the over-
heating of matters under the process of distillation, or when vegetable or
animal matter becomes burned in other processes in close vessels. It is said
that this peculiar odour is produced from no substance that does not contain oil;
hence, if no empyreuma is perceived in burning any substance in a close vessel,
we may be assured that it contains no oil.
ENAMEL. A shining vitrified substance, employed as an indestructible
coating to pictures, and various articles of taste and utility. . The basis of all
kinds of enamel is a perfectly transparent and fusible glass, which is subsequently
rendered either semi-transparent or opaque by the admixture of metallic oxides.
White enamels are composed by melting oxide of tin with the glass, and adding
a small quantity of manganese to increase the brilliancy of the colour. The
addition of the oxide of lead or antimony produces a yellow enamel. Reds
are formed by an admixture of the oxides of gold and iron. Greens, violets,
and blues, are procured from the oxides of copper, cobalt, and iron; and these,
when intermixed in different proportions, afford a variety of intermediate
colours. The proportion in which these ingredients are used, as well as the
degree and continuance of the heat necessary to their perfection, constitute the
secrets of the art. The best enamel was formerly imported from Venice; but
during the restrictions on commerce imposed by the late war, the importation
had almost wholly ceased. The high price of the article, therefore, induced
British artisans to attempt its manufacture, and they succeeded in producing a
hard enamel, superior to the best Venetian in whiteness, and much more valuable
to the dial-plate makers. In 1817 Mr. Wynn communicated to the Society
of Arts a series of receipts for the preparation of enamel colours, and for
which a premium was awarded by the Society. The fluxes are those em
ployed by Mr. Wynn.”
Parts.
Red lead . . . . . . . . . 8
Calcined borax . . . . . . . ] }
No. 1. # powder . . . . . . . . 2
Flint glass . . . . . . . 6
Flint glass . . . . . . 10
No. 2. 3White arsenic . . . . . . ... 1
C Nitre . . . . . . . . . I
Red lead . . . . . . 1
No. 3. {#. glass . . . . . 3
Red lead . . . . . . tº 9}
No. 4. # not calcined . . . . . 5}
Flint glass . . . . . . . . 8
Flint glass . . . . . . . . 6
No. 5 Flux, No. 2. . . . . . . . . 4
Red lead . . . . . . . . . 8
After the fluxes have been melted they should be poured on a wetted flag-stone,
or into a large pan of clean water, then dried, and finely powdered in a biscuit-
ware mortar for use.
To make yellow enamel: take red lead 8 parts, oxide of antimony 1, and
white oxide of tin 1. Mix the ingredients well in a biscuit-ware mortar, and
having put them on a piece of Dutch tile in the muffle, make it gradually red
468 ENAMELLING.
hot, and suffer it to cool. Take of this mixture 1 part, of flux, No. 4, 1}, and
grind them in water for use. By varying the proportions of red lead and anti-
mony, different shades of colour may be obtained.
To make orange enamel: take red lead 12 parts, red sulphate of iron 1, oxide
of antimony 4, and flint powder 3. After calcining these without melting, fuse
1 part of the compound with 2% of flux.
To make dark red enamel: take sulphate of iron, calcined dark, 1 part, flux,
No. 4, 6 parts, and of colcother 1 part; of the two latter mixed, add 3 parts.
To make light red enamel: take red sulphate of iron 1 part, flux, No. 1, 3,
and white lead 13.
To make brown enamel: take maganese 24 parts, red lead 84, flint powder 4.
ENAMELLING. The art of covering plates of metal with enamel is of
great antiquity; it was practised by the Egyptians, and by them probably
transmitted to the Greeks and Romans. Several ancient specimens of curious
workmanship prove its existence in Britain at a very early period. It was for-
merly employed chiefly for ornamental purposes, but since the invention of
clocks and watches, its usefulness has been proportionably increased. For
clock and watch dials there is probably no substance that could be substituted
that can equal enamel in permanence and beauty. The art of dial-plate
enamelling is divided into two branches, namely, hard enamelling, and soft or
glass enamelling. In the first branch the Venetian enamels are chiefly em-
ployed; in the last the English or glass enamels. The practice of hard
enamelling requires more skill, time, and labour, than the others, and is con-
sequently the most esteemed. The metals to be enamelled on are usually gold,
silver, or copper; but the process being similar, one description will suffice.
The copper, which is the metal usually employed, being evenly flatted in long
slips, and to a proper thickness, pieces are cut off for use according to the size
wanted; they are then annealed in a clear fire in order to make them suffi-
ciently pliable to take the required forms which are given to them by means of
brass dies. A complete set of dies varies in size from about three-fourths of an
inch, to two inches and a half, the gradations being very small. The copper is
next placed on the die best adapted for the purpose, and the eye, or centre
hole, is made with a small round-headed punch, and smoothed with a grained
file; it is then again placed on the die, and pressed gradually open, till it
nearly fills the hole with an oval burnisher; it is afterwards pressed tighter into
the hole with a round broach, the burr being occasionally taken off by the file,
and care employed to prevent the eye from cracking. #. punch, burnisher,
and round pin, are all of steel; the two latter taper in regular gradation
towards the handles. When the eye is completed, the edge of the copper is
cut round, so as to leave a small part projecting beyond the die, which is then
turned up or burnished against the edge of the die, the copper being first laid
smooth and flat by the burnisher, The copper is then gradually set up to the
convexity or height required by rubbing it gently, yet firmly, with a bent or
setting spatula, formed of a thin slip of steel about five inches long, properly
fixed, after which the feet are soldered on. The inconveniences that attended
the use of plain copper wire, soldered with spelter for the feet, are now entirely
obviated by employing copper wire plated with silver. The feet must be cut
by fixing an iron peg into the work-board; to the pieces of plated wire being
held against it, it will be found to form a very good resistance against the
action of the file. It should be observed, that if coppers are to be made for
flat plates, the feet should be filed at right angles; but if the plates are convex,
they should be filed at an angle as nearly as possible corresponding with the
curve formed in the hollow part of the copper, because when the foot is placed
on the copper it will be found to stand perpendicular to the base line or edge
of the copper. In order to make the feet remain in their places, and facilitate
the soldering, the end of each foot, before putting it on the copper, which is
done by means of a pair of corn tongs or tweezers, is dipped into a slight wash
of borax and water, through which it adheres with sufficient force to admit of
its being exposed to the power of the blow-pipe. The lamp in common use
contains from a pint to a quart of oil, and has a cylindrical spout projecting
ENAMELLING. 469.
about three inches, being an inch or more in diameter. This space is filled
with cotton, which being lighted, a strong flame is produced. The copper is care-
fully placed upon a piece of solid charcoal, long enough to be held in the hand;
and the flame being then propelled by the blow-pipe against the solder or silvered
wire, as the case may be, the feet are firmly united to the copper. The whole
is then thrown into the pickling-pan, in order to free it from the scale or oxid-
able covering acquired from the heat. The coppers being thus prepared, the
next process is that of enamelling, properly so called. The operations of hard
enamelling, and glass enamelling, are, to a certain extent, the same. When
they are different, we shall describe the difference as we proceed. The enamel,
as it comes from the makers, is generally in small cakes from four to five
or six inches in diameter. It is first broken with a hammer, and then ground
in a mortar, and moistened with water; after which, the coppers having been
first cleansed by the pickle, and carefully brushed out with water, are spread,
face downwards, over a soft cloth, or smooth napkin, and a thin layer of hard
enamel, called in its ground state the backing, is spread over the under sides
with the end of a quill, properly cut, or with a small bone spoon. The coppers
are then slightly pressed on by another soft cloth or napkin, which, by imbibing
some portion of the water, renders the enamel sufficiently dry to be smoothly
and evenly spread with the rounded side of a steel spatula. The next opera-
tion is to spread a layer of glass enamel over the upper sides of the coppers,
called the first coats. In doing this, the surface is first brushed slightly over
with a small camel-hair brush, or a hare's foot, to remove any dirt or extra-
neous particles of enamel, as the mixture of any hard enamel with the glass
would infallibly spoil the work. The glass is then spread upon the coppers in
a layer, the thickness of which is commonly the same as the height of the edge
and eye. The water is afterwards slightly absorbed with a clean napkin,
smoothly folded, and the enamel spread by a thin flat spatula, till all uneven-
ness is removed, and the surface lies regularly from edge to centre. The next
department is firing, as it is technically called, which consists in melting it till
it becomes one uniform mass on the surface of the copper. In doing this, the
first coats are placed upon rings, which are generally made of a mixture of
pipe-maker's clay and Stourbridge clay, rolled up into the form of cylinders,
and turned in a ñº. by means of a cylindrical piece of wood forced through
the centre of the mass when wet. They are next put into a shallow tin vessel
called a tin cover, which is either made square or round, according to the fancy
of the artificer, and is commonly about three quarters of an inch in depth. All
the moisture is then slowly evaporated from the enamel, by placing the cover
upon a German stove, or in some other convenient situation near a fire, where
the evaporation can be properly regulated. The firing is executed beneath a
muffle, placed in a small furnace, ignited with coke and charcoal. The fur-
nace being drawn up to a sufficient heat by means of a register, the first coats
are taken separately from the tin covers and placed upon thin planches of clay,
or iron chalked over, and gradually introduced beneath the muffle, where, in a
very short time, the enamel melts or runs, and becoming properly consoli-
dated, the first coat is complete. A second layer of ground enamel is then
gently spread with a quill, and prepared for firing by the napkin and spatula as
before; after which the second coats are placed upon the rings, and the mois-
ture being evaporated in the tin cover, they are ready for a second fire. This
requires an equally cautious management as the former one. The plates must
not be over-fired, nor must the heat be suffered to melt the enamel too rapidly,
but a kind of rotatory motion, called coddling, must be given to the work, by
holding the loaded planch lightly with the tongs, and gently drawing the edge
of it towards the mouth of the muffle, and then returning it to its former place,
till the fusion be complete. The work is now in a fit state for polishing, tech-
nically called using off. This is performed by rubbing the surface of the plate
on a grit stone with fine sand and water, until all the glazed appearance is
completely obliterated, and one uniform and equally rough surface is produced.
The intention of this part of the process is to remove the mottled appearance
on the surface, and give a more equal convexity to the plate.
3 o
470 ENAMELLED CARDS.
The foregoing is an outline of the process for glass enamel plates. The firing
of the Venetian hard enamel is much the same; but the heat applied to melt
it must not be so great, and the plate must be taken from the fire as soon as
the enamel is found to form one tolerably compact body, as any longer con-
tinuance would have a tendency to spoil the intended shape of the plate,
which is always considered a most essential quality in those of hard enamel.
The heat for finishing may be rather more than that used in the first fires, as in
that instance the intention was only to unite the particles of enamel into one
solid mass : but the principal object in finishing being to raise the flux to the
surface as much as possible, a greater heat may be used with advantage, but
the plate must be taken from the furnace the instant that the surface appears
bright and glossy. Where good Venetian enamel cannot be obtained, and
mixtures of various kinds are resorted to, it frequently happens that the glass
enamel plates crack when they are brought to the second fire. When this is
the case, as soon as the crack is observed the plate must be withdrawn from the
fire; and if it extends only from the centre hole to the edge, it will, in most
cases, bear mending; but if it has happened in two or three places, it will
be useless to make the attempt, as it will rarely succeed. If the dial plate was
to continue in the fire after it is cracked a sufficient time, the enamel would
close, and the plate become sound again; but as the copper on its surface is
in a state of oxidation, the oxide of copper uniting with the enamel would
rise to the upper surface of the plate, producing by its union a faint and some-
times a dark green line, which would evidently render the plate useless. The
operator, therefore, must observe the time when the crack has opened to its
greatest width, and before it unite or close at the bottom the plate must be
withdrawn from the furnace and allowed to cool. The opening must then be
filled with fine enamel, laid sufficiently high to allow for its running down in
the fire; but to adjust the quantity so as to prevent the appearance of a seam
across the plate will require much judgment; and, indeed, however well the
operation may succeed, it will still remain visible.
The method of painting in enamel is performed on plates of gold, silver, and
copper, enamelled with the white enamel; whereon they paint with colours
which are melted in the fire, by which they acquire a brightness and lustre like
that of glass. This painting is the most prized of all for its peculiar brightness
and vivacity, which is very permanent, the force of its colours not being effaced
or sullied with time as in other painting, and continuing always as fresh as
when it came out of the workman's hands.
ENAMELLED CARDS is a name given to the cards on which a coating in
imitation of real enamel is produced. We believe there are various processes
at present employed for fabricating these elegant and fashionable articles; but
the following account of Mr. Christ's process, which we derive from the speci-
fication of his patent, enrolled in August 1826, may be regarded as genuine and
practical. One pound of parchment cuttings, a quarter of a pound of isinglass,
and a quarter of a pound of gum arabic, are to be boiled in an open iron pot
or other vessel, in twenty-four quarts of pure water, until the solution is reduced
to twelve quarts, when it is to be taken off the fire and strained clear. The
solution of this consistence is then to be divided into three equal parts of four
quarts each; to the first of these portions is to be added six pounds of pure
white lead, (previously ground fine in water,) which is called mixture No. 1; to
the second portion, eight pounds of pure white lead, forming mixture No. 2;
and to the third is to be added six pounds of pure white lead, making mixture
No. 3. The sheets of paper are then to be stretched out upon flat boards and
brushed over with a thin coat of No. 1 mixture, with a common painter's brush;
the paper is then to be hung up to dry for twenty-four hours. After this, the
paper is in a similar manner to receive a coat of No. 2 mixture, and to be hung
up again to dry for twenty-four hours; the paper is then to be treated in the
like manner with No. 3 mixture, and then dried again for twenty-four hours.
It is next to be printed with the engraved plate, and the press-board used for
the purpose is to be of smooth cast iron instead of wood. The printing being
completed, the paper is to be hung up a fourth time for twenty-four hours to
EN CAUSTIC PAINTING. 471
dry; after this it undergoes the final operation of receiving its high gloss, which
consists in laying the work with its face downwards on a highly-polished steel
plate, and then passing both with great pressure between a pair of cylindrical
rollers, and thus the beautifully polished surface of the steel is transferred to
the composition on the paper, which closely resembles in appearance the finest
white enamel. It is, however, to be regretted that this enamelled surface is
not very durable, as it comes off readily after wetting it with the finger. To
prevent this, a solution of some resinous substance should be added in the
last operation.
ENCAUSTIC PAINTING. A method of painting, much in use among
the ancients, in which wax was employed to give a gloss to the colours, and
permanence to the work. From the meagre account given to us by Pliny of
the method, it is evident he was not in the secret himself; all the information
he affords amounts to this — that the colours made use of were fixed by fire,
and that wax was employed to give them a gloss, and preserve them from
being injured by the air. This ancient art, after having been long lost, was
restored by Count Caylus, a member of the Academy of Inscriptions at Paris;
and the method of painting in wax was announced to the Academy of Painting
and Belles-Lettres in the year 1753, through M. Bacheleir, the author of a
treatise de l’Histoire et du Secret de la Peinture en Cire, who had actually
painted a picture in wax in 1749, and he was the first who communicated to
the public the method of performing the operation of inustion, which is the
principal characteristic of the encausting painting. The cloth or wood designed
for the basis of the picture is waxed over, by only rubbing it simply with a
piece of bees' wax, the wood or cloth stretched on a frame being held hori-
zontally over, or perpendicularly before, a fire, at such a distance that the wax
might gradually melt, whilst it is rubbed on, diffuse itself, penetrate the body,
and fill the interstices of the texture of the cloth, which, when cold, is fit to
paint upon. But as water colours, or those that are mixed up with common
water, will not adhere to the wax, the whole picture is first to be rubbed over
with Spanish chalk or white, and then the colours are applied to it; when the
picture is dry it is put near the fire, whereby the wax melts, and absorbs all
the colours. Several improvements in the art of encausting painting were
proposed by Mr. J. H. Muntz, in a treatise by him on this subject. When the
painting is in cloth he directs it to be prepared by stretching it on a frame, and
rubbing one side several times over with a piece of bees' wax, or virgin wax,
till it is covered with a coat of considerable thickness. In fine linen this is
the only operation necessary previous to painting, but coarse cloth must be
gently rubbed on the unwaxed side with a pumice stone, to take off all those
knots which would prevent the free and accurate working of the pencil. Then
the subject is to be painted on the unwaxed side with colours prepared and
tempered with water; and when the picture is finished, it must be brought near
the fire, that the wax may melt and fix the colours. This method, however,
can only be applied to cloth, paper, or other substances through which the wax
can pass; but in wood, stone, metals, or plaster, the method previously described
may be observed. . In the year 1787, Miss Greenland, an amateur of painting,
communicated to the Society of Arts the knowledge of this art which she had
acquired during her residence at Florence, and at the same time made a present
to the Society of a picture executed by herself in this manner, and for which
the Society awarded her their honorary reward of a gold pallet. The following
are her instructions. “Take an ounce of white wax, and the same weight of
gum mastich, powdered. Put the wax in a glazed earthen vessel over a very
slow fire, and when it is quite dissolved throw in the mastich, a little at a time,
stirring the wax continually until the whole quantity of gum is perfectly melted
and incorporated; then throw the paste into cold water, and when it is hard
take it out of the water, wipe it dry, and beat it in one of Mr. Wedgwood's
mortars, observing to pound it first in a linen cloth, to absorb some drops of
water that will remain in the paste, and prevent the possibility of reducing it to
a powder, which must be so fine as to pass through a thick gauze. It should
be pounded in a cold place, and but a little while at a time, as after long beating
472 ENGRAVING.
the friction will in a degree soften the wax and the gum, and instead of their
becoming a powder, they will return to a paste. Make strong gum arabic
water, and when you paint, take a little of the powder, some colour, and mix
them together with the gum water. Light colours require but a small quantity of
the powder, but more of it must be put in proportion to the body and darkness
of the colours; and to black there must be almost as much of the powder as
colour. Having mixed the colours, and no more than can be used before they
get dry, paint with fair water, as is practised in painting with water colours, a
ground on the wood being first painted of some proper colour, prepared in the
same manner as is described for the picture; walnut-tree and oak are the sorts
of wood commonly made use of in Italy for this purpose. The painting should
be very highly finished, otherwise, when varnished, the tints will not appear
united. When the painting is quite dry, with rather a hard brush, passing it
one way, varnish it with white wax, which should be put into an earthen vessel
and kept melted over a very slow fire till the picture is varnished, taking great
care that the wax does not boil. Afterwards hold the picture before the fire,
near enough to melt the wax, but not to make it run; and when the varnish is
entirely cold and hard, rub it gently with a linen cloth. Should the varnish
blister, warm the picture again very slowly, and the bubbles will subside.
When the picture is dirty, it need only be washed with cold water.” Almost
all the colours that are used in oil painting may be employed in the en-
caustic method, and many which cannot be admitted in oil painting, as red
lead, red or piment, crystals of verdigris, and red precipitate of mercury, may
be used here. The crayons used in encaustic painting are the same with those
used in the common way of crayon painting, excepting those that are in their
composition too tenacious, and the method of using them is the same in both
cases. The encaustic painting has many peculiar advantages; though the
colours have not the natural varnish or shining they acquire with oil, they have
all the strength of painting in oil, and all the airiness of water colours, without
partaking of the apparent character or defects of either; they may be looked
at in any light, and in any situation, without any false glare; the colours are
firm, and will bear washing; and a picture after having been smoked and then
exposed to the dew, becomes as clean as if it had just been painted. In
retouching the new colours unite with the old ones.
ENCHASING, or CHAsiNg. The art of enriching and beautifying gold,
silver, and other metal work, by some design or figures represented thereon in
low relievo. It is practised only on hollow thin works, as watch cases, &c.,
and is performed by punching or driving out the metal from the under side,
so as to stand out prominent from the plane or surface of the metal. In order
to effect this, a number of steel blocks or puncheons are provided of different
sizes, and the design being drawn upon the surface of the metal, the workman
applies the inside upon the heads or tops of these blocks directly under the
lines or parts of the figures; then with a fine hammer striking on the metal
sustained by the block, the metal yields and the block makes an indenture or
cavity on the inside, corresponding to which there is a prominence on the out-
side, which is to stand for that part of the figure, and by successive applications
of the hammer to the various parts of the design, the whole figure is brought out
with a precision and effect which it seems almost impossible to produce by such
simple means.
ENGINE, among practical men, is a term used synonymously with machine;
but some eminent writers on Mechanics affect to distinguish it as designating
more complicated structures than ordinary machines, notwithstanding which
discrimination, these same writers define a cannon, which consists essentially
of only one piece or part, as an engine; and a jacquard loom, which essentially
consists of several hundred parts, as a machine!
ENGRAVING. The art of producing figures or designs upon metals,
stone, wood, and various other substances, by means of lines cut upon the sur-
face. In this extensive sense of the term, the art is doubtless of very great
antiquity, repeated mention being made in Scripture of seals, signets, and other
works of the graver; but the word usually signifies the art of producing
ENGRAVING. 473
designs as above for the purpose of being subsequently printed upon paper,
which copies are also called engravings; and in this sense of the term the art
does not appear to have been known or practised in Europe until the middle of
the fifteenth century. In the present day it is held in very great esteem, and
is very extensively practised. It may be divided into two branches, according
to the substances upon which the design is engraved, which is generally either
metal or wood, although glass and other substances have been occasionally em-
ployed. Of the metals, copper has, until within these few years, been almost
exclusively chosen for engraving, on account of its ductility, evenness of tex-
ture, and the softness and delicacy of the tints which may be produced upon it;
but latterly, steel plates have been very extensively employed for this purpose,
and although the engravings thus produced are perhaps somewhat inferior in
softness to those obtained from copper, a very high pitch of excellence has
been attained, and in point of durability the copper-plates will bear no com-
parison with steel-plates. Engraving on copper is performed in various styles,
the principal of which are, line engraving, mezzotinto, etching, and aquatinta.
Line Engraving is considered as the highest department of the art, and is
always employed in the illustration of historical subjects. In this style of
engraving the lines are all cut upon the copper by means of an instrument
called a graver, the roughness being removed by a triangular steel instrument
called a scraper. To trace the design upon the plate (which for every style of
engraving should be of the best copper well planished and burnished), it is
usual to heat the plate sufficiently to melt white wax, with which it must be
covered equally with a thin film, and then suffered to cool; the drawing is
copied in outline with a black lead pencil on paper, which is then laid with the
pencilled side upon the wax, and the back rubbed gently with a burnisher,
which will transfer the lead to the wax. The design is then traced with an
etching needle through the wax on the copper, when on wiping it clean it will
exhibit all the outlines ready for the engraver.
Mezzotinto Engraving differs entirely from the manner above described, and
is chiefly employed for portraits and imitations of Indian ink drawings. The
mode of proceeding is as follows:—the plate is prepared by scratching it
equally in every direction with a tool called a grounding tool, so as to remove
entirely the polish from the surface, which is thus converted into a chaos of
intersections, which, if covered with ink and printed, would present a perfectly
black impression upon the paper. To transfer the design to be scraped, it is
usual to rub the rough side of the plate with a rag dipped into the scrapings of
black chalk, or to smoke it with a burning wax taper, as in the process of
etching. The back of the design is then covered with a mixture of powdered
red chalk and flake white, and laid on the plate, and the outline of the design
being lightly traced with a blunt point, the red particles at the back are thus
transferred to the black ground of the plate in the form of a corresponding
outline; the process must then be carried on with a scraper, by restoring the
plate in the perfectly light parts of the intended print to a smooth surface, from
which the gradations are preserved by scraping off more or less of the rough
ground, but the burnisher is necessary to polish the extreme edges of drapery,
&c., when the free touch of the brush in painting represents a brilliant spot of
light. The deepest shades are sometimes etched and corroded by aquafortis,
and so blended with the mezzotinto ground added afterwards, that there is
nothing offensive to the eye in the combination. Many proofs are required to
ascertain whether the scraping approaches the desired effect, which is done by
touching the deficient parts with white or black chalk on one of the proofs, and
then endeavouring to make the plate similar by further scraping, or by relay-
ing the ground with a small tool made for this particular purpose, where too
much of the roughness has been effaced.
A third method of engraving consists in corroding the various lines by
means of aquafortis, the remaining parts of the plate being defended from the
action of the acid by being covered with a thin stratum of a composition which
resists its effects. This method is termed etching, and is employed both for
preparing the outline in other styles of engraving, and also for filling in and
474 ENGRAVING.
completing a picture; and the prints so produced resemble pen and ink draw-
ings. This style is distinguished for the inimitable spirit and freedom of which
it admits. The first stage of the process is the preparation of the plate, by
covering it with a thin even film of the composition or ground, as it is termed,
which is to protect it from the acid. This ground is a combination of asphaltum,
gum mastich, and virgin wax, melted over a fire in an iron pot. A piece of
this ground is tied on a piece of lustring for use, and another piece of silk is
made into a dabber by tying a quantity of cotton wool in it. The copper-plate,
secured at one corner by a hand vice, is to be held over a charcoal fire, and the
silk containing the ground rubbed over until every part is covered by the melted
composition; and before it cools, the silk dabber is applied in all directions,
until the surface of the plate is thinly and equally varnished. When this is
completed, several lengths of wax taper twisted together are to be lighted, and
the plate being held in the left hand by the vice, the right holding the wax
taper, is to be waved gently to and fro under the ground, carefully avoiding
touching it with the wick, yet causing the flame to spread smoothly over the
surface, which will render it perfectly black, smooth, and shining in a short
time. The next object is to transfer the design to the ground, which may be
done either by making a tracing with a black lead pencil, or with vermilion,
upon thin paper, and applying it carefully to the plate, pass the plate through a
rolling-press; or the back of the design may be rubbed with red chalk and fas-
tened to the plate at the corners, and the outline then gone carefully over with
a blunt tracer. The outline thus prepared is then gone over with an etching
needle, which cuts through the ground; but particular care must be taken that
the point of the needle, though taper, be rounded, so as to avoid the possibility
of its tearing the surface of the copper, which would prevent the progress of the
point, and ruin the plate when bitten. The different shades and tints are then
worked up by the needle, the arrangement of the lines of which they are com-
posed depending entirely upon the taste and judgment of the artist. When
the etching is completed, the edges of the plate are surrounded by a high
border of wax, so well secured that water will not penetrate between it and the
plate. The best spirits of nitre must then be diluted with water, in the pro-
portion of one part of the former to four of the latter, and poured upon the
plate. In a short time numerous small air bubbles collect over every line
traced by the needle through the ground; these bubbles are caused by the
action of the acid upon the copper, and must be removed with a feather. When
it is judged that the lighter tints are sufficiently corroded, the acid is poured off
the plate, which is then washed, suffered to dry, and the light parts stopped
out, as it is termed, that is, covered with a composition of turpentine, varnish,
and lamp black, diluted so as to be used freely with a camel's-hair pencil; this
prevents the aquafortis from touching these parts again. . After this the acid is
again applied until the next depth of tint is obtained, which parts are in their turn
stopped out; and thus the process continues, alternately biting in and stopping
out, until every gradation of tint is obtained. The ground is then removed by
covering the plate with olive oil, heating it, and then wiping it with a piece of
oid linen dipped in spirit of turpentine, which effectually removes all remaining
dirt. If upon proving the plate, any part should be found not sufficiently cor-
roded, it must be rebitten, which is effected by applying the ground so care-
fully as not to fill in the lines, but merely to protect the surface of the plate;
and then raising a border of wax round the parts to be rebitten, apply the acid
as before. When the operations of etching and rebiting are entirely finished,
nothing remains to be done but to examine the plate attentively, and improve
it with the graver and dry point.
The last style of copper-plate engraving which we shall notice is the aqua-
tinta. The prints from an aqua-tinted plate greatly resemble a neatly-tinted
Indian ink drawing. This effect is produced by covering the plate with a
thin coating of various substances finely granulated, which defend it from
the acid where they cover it, whilst the interstices amongst the particles or
grains are corroded. The first step is to lay an etching ground, and to bite in
lightly the outline, after which the plate is cleaned and polished with whiting,
ENGRAVING. 475
previous to laying the grain. The best mode of laying the grain is as follows:
common resin, gum mastich, or Burgundy pitch, is dissolved in highly rectified
. of wine of the best quality; each of these substances produce a different
escription of grain, of which that from resin is the coarsest; but they may be
mixed in such proportions as the artist prefers, who, to satisfy himself on this
point, should try the grain of each proportion on useless slips of copper. Having
obtained a solution to his mind, it must remain undisturbed until every impure
particle has subsided, when it is poured upon the plate, which is held slightly
slanting, until the most fluid parts run off, after which it is laid to dry, in the
progress of which the resin granulates, and adheres firmly to the surface. The
grain being thus laid, the various tints are obtained by biting in and stopping
out, as in etching.
Another style of engraving has been introduced within these few years, called
machine engraving or ruling, in which the lines are ruled with a diamond point
on an etching ground, by means of a machine invented for the purpose by the
celebrated Lowrie. This machine is capable of producing lines straight or
waved, and either parallel or converging to any given point, as also parabolas,
hyperbolas, and most other geometrical curves and circles varying from a point
to a five-feet radius. The lines thus ruled are afterwards bitten in, in the usual
manner, as in ordinary etching. This style is now universally employed for
architectural and mechanical subjects, as also for putting in the buildings and
skies in the works of line engravers.
Steel Engraving, as we have already said, is extensively employed in the
illustration of works of which very large editions are printed, on account of the
durability of the steel plates, which is so great, that artists' proofs have
sometimes been taken after 20,000 impressions have been thrown off, whereas
a copper-plate will generally require touching after 1500 or 2000 impressions.
But before steel can be cut by the graver it requires to be softened, by depriving
it of a portion of its carbon, which is effected by imbedding the steel to the
depth of half an inch on all sides in a bed of pure iron filings, contained in a
cast iron box with a well closed lid. In this box the steel is to be exposed
for four hours to a white heat, after which it is to be suffered to cool very
slowly, which is best effected by shutting off all access of air to the furnace,
and covering the box with a layer of fine cinders to the depth of six or seven
inches. After the steel plate has been engraved, (which engraving may be in
any of the styles practised on copper,) it requires to be hardened or reconverted
into steel, which is effected by the following process: a suitable quantity of
leather is reduced to charcoal, by exposing it to a red heat in an iron retort for
a sufficient length of time; a cast iron box, whose cavity is about an inch
greater than the thickness of the steel plate, is then to be filled with this
charcoal reduced to a fine powder, and being covered with a well-fitted lid, it
is to be exposed to a heat somewhat above a red heat, until all the volatile or
evaporable parts are driven off from the charcoal. The lid is then removed,
and the plate immersed in the charcoal, as nearly as possible in the middle, so
as to surround it on all sides with a stratum of uniform thickness. The lid
being replaced, the box must remain in the degree of heat before described,
from three to five hours, according to the thickness of the plate. After
remaining in the fire the requisite time, the plate is taken from the box and
plunged immediately into cold water, from which it must be withdrawn before
the hissing noise has ceased; but the precise point for this cannot be explained
in words, and can only be learned by actual observation. The plate is then to
be immediately laid over a fire, until its temperature is raised to that degree
that smoke would arise upon rubbing the surface with tallow, when it must be
again plunged into water, where it remains until the hissing sound becomes
somewhat weaker than before. The process of heating and cooling is then to
be twice repeated, after which, the surface of the plate is to be cleaned, and
the temper finally reduced by heating it over a fire, until it acquires such a
shade of colour as denotes that the steel is of the fit quality for the required
purpose. For the process above described for softening and then rehardenin
steel plates, we are indebted to Mr. Perkins, it constituting an important ºf
476 ENGRAVING.
of an art invented by that gentleman, and to which he has given the name of
Siderographia. By means of this truly wonderful invention, not only are en-
graved steel plates obtained, whose durability is unknown, (since Mr. Perkins
states that he has taken 500,000 impressions from one plate,) but a plate being
engraved, other plates may be produced from it, which shall be fac similes of
the original. The method by which this astonishing effect is obtained is as
follows: A steel plate is engraved or etched in the usual way; it is then har-
dened. A cylinder of very soft steel, of from two to three inches diameter, is
then made to roll backwards and forwards on the surface of the steel plate,
until the whole of the impression from the engraving is seen on the cylinder in
relievo; after this cylinder has been hardened, it is made to roll backwards and
forwards on a copper or soft steel plate, and a perfect facsimile of the original
is produced of equal sharpness. But not only is perfect identity thus obtained,
but the two styles of work, viz. copper-plate printing and letter-press may be
beautifully combined, by means of the process of transferring and retransferring.
This invention is admirably adapted to the prevention of forging bank notes, as
by this means several first rate artists may be employed at one time to produce
portions of a plate in detached parts, which may afterwards be combined and
arranged in any order to produce a single plate, and before the note could be
imitated by forgers it may be called in and a new note issued, consisting of the
same parts differently arranged; the principle, also, offers various other modes
of defeating attempts at imitation. The invention has accordingly been very
extensively patronized by the banks in America from its outset; and at the
present time the notes of most of the provincial banks in this country are pro-
duced by this process, some of them presenting the most beautiful specimens
of the art of engraving ever witnessed. The bank of England, however, for
reasons which are variously stated, has declined availing itself of the advantages
which the plan holds out, and after going to an expense of more than 30,000l.
in endeavouring to improve the quality of its notes, and to render them more
difficult of imitation, still continues to issue the same wretched description of notes
as have been so extensively and successfully counterfeited for many years past.
Wood Engraving is a process which is the reverse of copper-plate engraving,
for in the latter, the incisions made in the metal receive the ink and print the
design, while in the former, the raised parts form the design, receive the ink,
and transfer the subject to the paper. Accordingly, in engraving a block of
wood, the subject of which is to be represented by black lines, all those parts of
the space occupied by the design, which are not drawn upon, are entirely cut
away, whilst all the permanent lines of the drawing are left
untouched by the graver, as shown in the subjoined profile
sketch of a face. In work of this kind it is obvious that the
engraver can easily produce a perfect fac-simile of the artist's
drawing; in fact, his manual skill only is exercised to leave
the lines of the design untouched, by carefully cutting away
all the wood, and so deep that no other part of the block
shall take the printer's ink from the dabber or roller, and
that the paper in printing shall not reach the sunken parts. /
The process of clearing away the wood without damaging
the lines of the drawing, is, of course, a nice operation;
nevertheless, a learner in the space of two or three months
acquires such dexterity with his little tools, that he cuts away nearly as fast as
he can move his hand or fingers. Before, however, the engraver commences
to “clear out” his work he “outlines it,” which consists in carefully running a
very sharp narrow-pointed graver along both sides of the lines of the drawing;
this insures more accuracy and clearness in the subsequent operation, and to
prevent the back of the graver from injuring the lines of the design, the engraver
occasionally in difficult parts defends the lines by covering them with a thin
§: of metal, which he holds down upon the work with the fingers of his left
a.I] Ol.
A much easier, and therefore cheaper mode of engraving on wood, is to make
white lines on a black ground, as represented in the engraving on the next page.
\

ENGRAVING. 477
in this case the block of wood is supposed, as in the former case, to have the
profile drawn upon it, but instead of leaving the artist's lines upon the wood, he
cuts them away alone, leaving the rest of the wood the same
true plane it was before. The latter, therefore, receives the
ink, and delivers it upon the paper, while the incisions, taking
up no ink, leave their traces like white lines upon the paper.
This mode of engraving on wood is, therefore, analogous to
that upon copper plates, but the inking is different; as in the
latter case the ink is rubbed into the lines or incisions, leaving
the surface clean, and therefore the lines only of the copper
plate are imprinted. The taste of a wood engraver is most
exercised in softening the shadows and graduating the lights
of his subject. A consideration of the following sketch will explain to the reader
the principle upon which the engraver works. In the upper figure the strong
light upon the top of it is produced by first cutting
down in mass the upper surface at that part, by shelving
or inclining the sides to the cavity made, so that when
the parallel straight lines or tint is cut, their extremities
become so extremely fine and tapering, that they can
scarcely receive or deliver any ink, by their being sunk
below the plane of the other parts. In the distance it “
will be noticed that the lines are very near together, Š
to give the effect of distance, while those in front are `
comparatively wide apart, to give the effect of nearness. These different spaces
are produced by gravers of different breadths of point. For this purpose the
engraver provides himself with six or eight tinting gravers, which he numbers
from 1 to 6 or 8, taking them up and changing them in his work as the subject
requires. In the figure underneath, it will be seen that a strong light and a very
deep shadow are brought very near together, but without offending the eye by
too great abruptness. This is effected by continuing the white lines of the
light part by lines of diminished thickness over the black or solid part, with a
fine graver. A very close imitation of copper engraving may be made upon
wood, so as to have great force and clearness in some kind of subjects, but can
only be afforded by the engraver when he is duly paid for the great extra labour
attending it. This consists in crossing the lines in the manner shown by a little
bit at a, in the bottom corner of the preceding figure. The diamond-shaped
pieces are every one picked out by the graver, and these, in some fine wood
engravings, are extremely minute; nevertheless, the lines, however fine, are
left clear and unbroken. To show the freedom, ease, rapidity, and consequent
cheapness with which white lines may be executed
upon a black ground, we have added the annexed
illustrated cut, which was executed by an expert N
engraver in the space of three or four minutes. The ºs
wood made use of is mostly box, the best of which Fes
comes from Turkey. The tree is cut into slices
transversely to the grain, and then rendered to a true É
plane and smoothed. On this fine compact surface
the subject is drawn, either with black lead pencil or T
with Indian ink; but the latter is preferable (except for
works of high finish), as it is not so liable to be effaced ;
during the process of engraving. The art of engraving
on wood is coeval with the art of printing, in #.
the earliest books being printed from wooden blocks, each block comprising a
page, as is the method at the present day in China, in which country the art,
it is said, has been practised so far back as the christian era. After flourishing
for a time in Europe, the art seems to have fallen into neglect, from which it
was first rescued in England by the celebrated Bewick, since whose time it has
risen gradually in repute and eminence, and now occupies a respectable station
amongst the fine arts. The superior utility of wood engraving consists in the
great durability of the blocks, but more especially in the peculiar advantage it



3 P
478 EQUIV A LENTS.
possesses of ranging with type, and being printed with it; which renders it
particularly adapted for the illustration of mathematical and mechanical subjects,
as the necessary diagrams and figures can be introduced in the body of the
letter press, wherever it is most convenient for the elucidation of the subject.
The blocks may likewise be stereotyped along with the type, as is now very
generally practised with standard works.
ENTABLATURE, in Architecture, is that part of an order of a column
over the capital; and comprehends the architrave, frieze, and cornice. Mr.
Nicholson, author of The New Practical Builder, says, “In buildings upon
magnificent scales, projections, similar to the entablatures just mentioned, are
carried round the edifices, and, where the expenses are limited, along the front
only : these projections are also termed entablatures.” In this sense the term
is applied by engineers to similar parts of the framing of machinery wherein
architectural designs are introduced.
EPICYCLOID, in Geometry, a curve generated by a point in one circle,
which revolves about the circumference of another circle. They are distin-
guished into exterior and interior epicycloids. An exterior epicycloid is formed
by revolution of a generating circle upon the convexity of the quiescent circle;
and an interior epicycloid is formed by its revolution along the concavity of the
quiescent circle. A curious property of the latter description of epicycloid is,
that when the diameter of the generating circle is equal to the radius of the
quiescent circle, the epicycloid described is a right line equal and coincident
with the diameter of the latter. Mr. Murray, of Leeds, applied this property
to obtain a rotatory motion of the fly-wheel of a steam engine directly from
the piston rod, without the intervention of a connecting rod. Epicycloids have
been recommended by many eminent mathematicians as the best curve for the
teeth of wheels; but in practice they are usually formed of circular arcs, as
these work very well, and are easier of construction. --
EQUATION, in Algebra, is an expression in which two quantities, differently
represented, are put equal to each other by means of the sign = placed between
them, as 3 a b- d.
EQUILIBRIUM, in Mechanics, signifies an equality of forces in opposite
directions, whereby the body remains at rest, or in equilibrio; in which state
the least additional force being applied on either side, motion will ensue.
EQUIVALENTS, CHEMICAL. A term happily introduced into chemistry
by Dr. Wollaston, to express the system of definite ratios in which the corpus-
cular objects of this science combine, referred to a common standard of unity.
The two grand laws of chemical combination are, 1st, The general reciprocity
of the saturating proportions; and 2d, The definite proportions in which bodies
combine; and if any substances are capable of combining in more than one
proportion, such combinations are always multiples, or submultiples of one of the
proportions. The first of these laws was discovered by Richter, in 1792, who
inferred it from the remarkable and well established fact that two neutral salts,
in mutually decomposing each other, give birth to two new saline compounds,
always perfectly neutral. Thus sulphate of soda being added to muriate of
lime, will produce perfectly neutral sulphate of lime and muriate of soda.
From this he concluded that the quantities of two alkaline bases adequate to
neutralize equal weights of any one acid, are proportional to the quantities of
the same bases requisite to neutralize every other acid. For example: 6 parts
of potash, or 4 of soda, neutralize 5 of sulphuric acid; and 4.4 of potash neu-
tralize 5 of nitric acid. Therefore to find the quantity of soda equivalent
to the saturation of this quantity of nitric acid, we need not make any experi-
ment, but merely compute it by the proportional rule of Richter. Thus—as
6 : 4.4 :: 2.93, the weight of soda required to saturate 5 parts of nitric acid;
and this proportion of 6 to 4, or 3 to 2, will pervade all the possible saline
combinations of these bases, so that it will require only two parts of soda to
saturate as great a quantity of any acid as could be saturated by three parts of
potash. The doctrine that bodies combine chemically in certain definite pro-
portions, was first promulgated by Dr. Higgins, in his Comparative View of the
Phlogistic and Aniiphlogistic Theory, published in 1789. This doctrine was
ESSENTIAL OILS, 479
subsequently maintained by Mr. Dalton, in his New System of Chemical Philosophy,
first framed about the year 1803, and published in 1808. In this work Mr.
Dalton fully establishes the proposition that bodies do not combine in all pro-
portions, as Berthollet maintained, but that the different compounds of the same
principles proceed in successive proportions, each a multiple of the first. This
proposition has been further illustrated and confirmed by the researches and
reasonings of the most eminent chemical philosophers, and is now universally
admitted to be true. In the first part of the Philosophical Transactions, appeared
Dr. Wollaston's description of his scale of chemical equivalents; an invention
which has contributed more to facilitate the general study and practice of
chemistry, than any other invention of man. This singularly useful con-
trivance consists of a flat ruler, about 2 inches wide and 18 inches long, on
which a list of substances are arranged on one or other side of a logarithmic
line of numbers, in the order of their relative weights, and at such distances
from each other that the series of numbers placed on a sliding scale can at
pleasure be moved, so that any number expressing the weight of a compound
may be brought to correspond with the place of that compound in the adjacent
column. The arrangement is then such, that the weight of any ingredient in
its composition, of any reagent to be employed, or precipitate that might be
obtained in its analysis, will be found opposite the point at which its respective
name is placed. For example:—If the slider be drawn upwards till 100 cor-
responds with muriate of soda, the scale will then show how much of each
substance contained in the table is equivalent to 100 of common salt. It
shows with regard to the different views of this. salt, that it contains 46.6 dry
muriatic acid, and 53.4 of soda, or 39.8 sodium, and 13.6 oxygen; or if viewed
as chloride of sodium, that it contains 60.2 of chlorine, and 39.8 sodium.
With respect to reagents, it may be seen that 283 nitrate of lead, containing
191 of litharge, employed to separate the muriatic acid, would yield a pre-
cipitate of 237 muriate of lead; and that there would then remain in solution
nearly 146 nitrate of soda. These, and many more such answers, appear at
once by bare inspection, as soon as the weight of any substance intended for
examination is made by motion of the slider to correspond with its place in the
adjacent column. , Dr. Wollaston took, as his standard or unity, oxygen, from
its almost universal relation to chemical matter, and determined the equivalents
of other substances by their relation to this standard. Sir H. Davy proposed
as unity, hydrogen, which is the lightest of all known substances, and which,
therefore, seems preferable as the basis of the scale, since the equivalents of
all other substances must necessarily be expressed in all numbers without frac-
tions; and this scale has, accordingly, been extensively adopted.
ERMINE. A fine description of fur, obtained from the skin of an animal
of the same name.
ESSENCES. Several of the volatile or essential oils are called essences by
the perfumers.
ESSENTIAL OILS, (called also volatile and ethereal,) are distinguished
from fixed or fat oils, from the circumstance of their rising in distillation at
temperatures below that of 3200 Fahr. by themselves. They are mostly
obtained from odoriferous vegetable substances, although some of the principles
are found in animal matter. In different vegetables these oils are found
variously lodged,—sometimes in the bark, as in cinnamon; sometimes in the
root, as in the plant that yields the true camphor; sometimes in the wood, as
in the cedar; sometimes in the leaves, as in mint, balm, &c.; sometimes in the
flowers, as in the carnation and rose; sometimes in the rind, as in the orange
and lemon ; and, in a great variety of instances, in the seeds or fruit. The
plants should be collected at the time their scents are the most powerful, and
in most instances it is preferable to dry them previous to distillation, to get rid
of some of the acid juices of the sap of the plant, which, by enabling the water
with which they are distilled to dissolve more of the oil than it otherwise would,
would diminish the produce. The drying of the plants should, if possible, be
in the sunshine, but where this is not practicable, it should be effected as quickly
as possible on a kiln. Woods must be reduced to shavings; barks, and similar
430 ESSENTIAL OILS,
substances, to a gross powder; and these in general require to be soaked
for some days before they are distilled, in water sharpened with salt, or a
little muriatic acid. The still, if of copper, should be well tinned inside, and
have a low head, that the oil may not have to rise high. The old alembic
answers well, with the simple mode therein adopted of condensing at the capital
or head, either by a small reservoir of water fixed thereon, or by enveloping
the head with flannel, and allowing water to drip upon it. No more water
should be added than is necessary to bring over the oil, and prevent the matter
from burning in the still ; hence, the goods should be first floated with water,
and then more added by weight or measure, to determine the necessary quantity.
In goods that yield their oil easily, about six times their weight is sufficient;
but in others which yield their oils with difficulty, as the woods, about ten times
their weight must be added. The distillation is conducted with a quick fire,
until the quantity of water that was added is come over; and if the last portions
bring over any oil with them, the fire is slackened, and the distilled water
returned into the still, and brought over a second time; sometimes it is found
necessary to distil it a third time. . As some oils congeal at a low temperature,
it becomes necessary that the condenser be not kept so cold as to produce that
effect, but at that temperature by which the oils would preserve their liquid
form, in order that they may flow out into a receiver. And as it is difficult to
clean out the convoluted worms of ordinary condensors, those with straight or
zigzag tubes are preferable where more than one kind of oil is made, otherwise
the odour of one would be mixed with another. The quantity of oil which
comes over being extremely small in comparison with that of the water, it is
proper to have a receiver that will allow the water to run off into another
vessel, while it retains the oil. The water used in a previous distillation may
be advantageously used in a second, and sometimes a third distillation, to save
that portion of the oil which always combines with fresh water. It is, however,
to be observed, that by frequent cohobation, the water acquires acid properties,
and then takes up a larger quantity of oil, and diminishes the produce.
Roses should be distilled with their green flower cups, and be torn open with
the nails, as the liquid or scented oil is lodged in a cell at the claw of each
petal. By adding a little muriatic acid to the water, and digesting for a few
days, the produce is doubled. The essential oil of bitter almonds requires
particular treatment, and the distillation should be conducted in the open air,
to prevent the deleterious effects, of its vapours, which cause severe head-ache
and fainting to all persons within its influence. The usual process consists first
in pressing the almonds, to separate the fixed oil, and then grinding the resulting
oil cake to a coarse powder. Thirty pounds of this powder is then to be dis-
tilled with eight gallons of water, until the whole is come over, when there will
be found floating about three-quarters of an ounce of essential oil; this is to be
taken off, and then as much salt as the water will dissolve is to be added to it,
and about a gallon of this being distilled, a further produce of four or five
ounces of the essential oil will result therefrom. The essential oil of tur-
pentine, called also spirit of turpentine, is prepared by distilling turpentine in
iron stills with a condensing apparatus, until the drops of oil begin to grow
coloured. One hundred-weight of turpentine yields from twelve to twenty
pounds of oil; the product is found to be greater in proportion to the slowness
of the operation. For medical purposes the turpentine is either distilled with
water, or rectified with it, but as a portion of water thus combines with it, it is
not adapted to painters' use. The essential oils of aniseed, camomile, caraway,
cassia, cinnamon, cloves, dill, juniper berries, mint, nutmegs, penny-royal,
peppermint, rue, Sassafras, savine, and wormwood, are used in medicine as
carminatives and stimulants. Those of aniseed, caraway, º cinnamon,
cloves, juniper, and pepper, are used in compounding the cordial waters of
the spirit dealers. A third class, as those of balm, citron flowers, lavender,
orange flowers, roses, rosemary, sandal, thyme, are used to scent and flavour
spirits of wine, to make what are called toilet waters, as eau de Cologne,
Hungary water, &c. which are employed as cordials. The essential oils of
balm, calamus aromaticus, camomile flowers, caraway seeds, hyssop, lavender
EUDIOMETRY. 481.
flowers, marjorum, milfoil, parsley, rosemary, sage, Sassafras, thyme, are used
to scent soaps.
ETHER. See AETHER.
EUDIOMETRY. The measurement of the quantity of oxygen contained
in atmospheric air, or, indeed, in any gas in which it is not intimately com-
bined, is named eudiometry, and the instrument by which it is performed is
named the eudiometer. There are two modes of effecting this; either by pre-
senting to the oxygen any substance having a strong affinity for oxygen, or by
exploding it with hydrogen in a strong glass vessel by means of the electric
spark, and in either case estimating the quantity by the decrease in the bulk of
the gas. In the first method, the substances usually employed to absorb the
oxygen, are either phosphorus, sulphuret of potash, or nitrous gas, which
latter substance, when used according to the directions of M. Gay Lussac,
seems preferable to any other; these directions are as follows:–Take a very
wide tube or tumbler, for example, invert it in water, and having introduced
into it 100 parts of the air to be examined, pass into it 100 parts of nitrous
gas. There is instantly exhibited a red vapour, which is nitrous acid gas, and
which being very soluble in water, disappears speedily without agitation, and
after a minute at most the absorption is complete; then transfer the residuum
into a graduated tube, and it will be found that the absorption is almost
uniformly 84 parts, provided atmospheric air was used; and as nitrous acid
(the resulting compound) consists of three volumes of nitrous gas and one
volume of oxygen, one-fourth of the absorption, equal 21 parts, indicates the
quantity per cent. of oxygen. M. Gay Lussac shows by numerous experi-
ments, the accuracy of the above process in varied circumstances. There is
this great advantage attending it; that the proportion of oxygen gas being
estimated by an absorption four times greater than its own volume, the
errors of experiment are reduced to one-fourth. The analysis of combustible
gases, and the supporters of combustion, reciprocally by explosion with the
electric spark, furnishes, when it can be applied, one of the most elegant and
speedy methods of chemical research ; but is attended with some danger, from
the liability of the tube to burst, if a close tube is used, or with a risk of failure
from the ejection of the mercury when the tube is merely sealed by that fluid.
This has given rise to several modifications of the apparatus, most of which are
somewhat complex and costly; but that invented by Dr. Ure, and communicated
by him to the Royal Society of Edinburgh, is at once simple, cheap, and
effective. It consists of a glass syphon, having an interior diameter of from
two-tenths to four-tenths of an inch. Its legs are nearly of an equal length,
each being from six to nine inches long. One end is open and slightly funnelled;
the other end is hermetically sealed, and has inserted near it by the blow-pipe
two platina wires. The outer end of one wire is incurvated across, so as nearly
to touch the open end of the tube; the outer end of the other wire is formed
into a small hook, to allow a little spherical button to be attached to it when
the electric spark is to be transmitted. To use it, the whole syphon must be
filled with water or mercury, then plunge the open leg into a pneumatic trough,
and introduce into it any convenient quantity of the gases from a glass measure
tube, containing them previously mixed in determinate proportions. Then,
applying a finger to the orifice of the syphon, remove it from the trough,
and transfer the gases into the sealed leg, by holding the syphon leg
uppermost. Then bring the mercury to a level in both tubes, by adding or
displacing a portion, and note carefully the volume of gas in the sealed leg, which
should be graduated to one hundredth parts of a cubic inch. Then applying
again the fore finger to the orifice, so as also to touch the end of the platina
wire, bring the pendant ball or button to the electric machine, and transmit the
spark. After the explosion, on gradually sliding the finger to one side, and
admitting the air, the mercury will rise in the sealed leg more or less above that
in the other; then pour in mercury till the equilibrium be restored, and read
off, as before, the bulk of the remaining gas, and the difference of the two
volumes will denote the true quantity of oxygen, without requiring any
reduction or allowances. So perfectly is the shock of the explosion deadened
482 EWAPORATION.
by the elasticity of the air confined between the finger and the surface of the
mercury in the open end of the tube, that nothing but a slight push or pressure
at the tip of the finger is felt, even when the included gas is in considerable
quantity and of a highly explosive nature; and the projection of the mercury
or displacement of the gas is obviously impossible.
EVAPORATION. A term generally used to signify the dissipation of the
volatile parts of a compound body, whether caused by the action of the sun
and atmosphere, or by artificial means; although some authors restrict the use
of the word to the former case, and employ the term vaporization in the latter.
A distinction is likewise drawn in the case where the volatile parts are the
objects of the process, which is then termed distillation; but the fixed parts, or
the residuum, are the products sought by evaporation. The vessels are
accordingly different, evaporation being commonly carried on in open shallow
vessels, and distillation in vessels nearly closed from the external air. The
degree of heat must be duly regulated in evaporation. When the fixed and
more volatile matters do not differ greatly in their tendency to fly off, the heat
must be very carefully adjusted; but in other cases this is less necessary. As
evaporation consists in the assumption of the elastic form, its rapidity will be
in proportion to the degree of heat and the diminution of the pressure of the
atmosphere; a current of air is likewise of service in this process. Dr. Ure, in
his Chemical Dictionary, mentions the following method of evaporating liquors,
as being practised in some large alum manufactories. A water-tight stone
cistern, about three or four feet broad, two feet deep, and from twenty to forty
feet long, is covered over by a low brick arch. At one extremity of this tunnel
a grate is built, and at the other a lofty chimney. When the cistern is filled,
and a strong fire kindled in the reverberatory grate, the flame and hot air
sweep along the surface of the liquor, raise the temperature of the uppermost
stratum almost instantly to near the boiling point, and draw it off in vapour.
The Doctor observes, that the great extent, rapidity, and economy of this
process recommend it to general adoption on a large scale.
More recently, Mr. Jacob Perkins has obtained a patent for a novel mode of
forming steam of very high pressure, by confining the water under mechanical
pressure, in a boiler properly constructed for the purpose and intensely heated;
Fig. 1.
&
Y
F==3
gº ºººººººº- *~º-º-º-reeº-º:
Fig. 2:
and subsequently he obtained another patent for an adaptation of that appa-
ratus for the evaporating of water and other fluids. For this purpose the
high pressure steam is projected from the generator through pipes which
circulate through the evaporating pans or boilers; and such an arrangement is



EWAPORATION. 43.3
made, that the water produced by the condensation of the steam is returned
into the generator by means of valves and a force pump, the steam or water
being always under mechanical pressure. The preceding engravings give
a sectional elevation and a plan, and the same letters of reference apply to
similar parts in each figure. a is the generator; b the forcing pump; c a pipe
opening into, and projecting from the upper part of the generator at d, and
opening to, and projected from the lower part of it, opposite to e : f is a pipe
leading from the pipe c to the forcing pump; g is a valve; h a vessel, containing
the liquid to be boiled or evaporated; and j a safety valve. At l, in the plan,
is a valve opening into the generator; it is not seen in Fig. 1, but is in a line
with the part marked e in that figure. When steam is admitted from the
generator into the pipe c c, it becomes condensed in heating the surrounding
fluid in the vessel h, and collects in the form of water at the valve g. Upon
raising the handle of the forcing pump, the valve g opens, and the water fills
that portion of the pipe marked f between the pump and the valve g, the
pressure in the generator keeping the valve at the opening l shut. When the
handle of the force pump is depressed, the valve g shuts, and the water being
prevented, in consequence, from returning into the pipe c, necessarily forces
open the valve at l, and is returned into the generator; and this operation is of
course successively repeated at every stroke of the piston rod of the pump.
Messrs. Beale and Porter's patent method of applying heat for the purposes
of evaporation, consists in the use of various fluids as media for the communi-
cation of heat, which rise in vapour or boil at different degrees of temperature;
so that one substance may be chosen as proper for one process, and another
substance or combination of substances may be employed as more suitable for
other processes, the nature of these substances being such that, under the ordinary
pressure of the atmosphere, each will indicate a known and unvarying degree
of heat at its boiling point, which may be communicated to any substance
exposed to its action. Amongst the numerous substances suitable for heating
media, are the following: Spirits of turpentine, which boils at 3160 Fahr., and
naphtha, which boils at 4000 Fahr.; and by distilling coal tar, and collecting the
products at different periods, various other bodies are obtained, which will
furnish different degrees of heat ranging between 4000 and 7000 Fahr. By
this arrangement it was expected that the maximum degree of heat would be
always and altogether independent of accident or want of skill, so that no
injury from burning could possibly arise, except through the employment of an
improper medium, which, as fluids may be chosen whose boiling points vary
between the range of 2000 and 7000 Fahr., need never occur. The mode of
applying this principle to boiling or distilling, is, by using a double vessel,
having one part placed within the other, so as to leave a small intermediate
space. Into this space the substance intended to form the medium must be
introduced, in sufficient quantity to cover the flat bottom of the outer vessel, to
such a depth as to secure it from injury by means of the fire. When this
fluid is made to boil, it will give off vapour of the same temperature, which, as
it comes in contact with the surface of the inner vessel, will part with its heat
thereto, and, resuming the fluid form, will fall again to the bottom of the vessel,
to be again vaporized; and so on, in a constant alternation of evaporation and
condensation. To keep up a communication between the fluid medium and the
atmosphere, and avoid thereby all tendency to rupture or explosion, a tube, open
at both ends, is introduced into the intermediate space between the vessels.
Should there be gross mismanagement of the fire, some portion of the vapour
would be forced up this tube; it is therefore made to pass through a condenser,
the action of which will return the fluid to the double vessel, so that little or no
waste of the fluid medium will be sustained. This mode of evaporating has,
we understand, been applied with great advantage in the refining of sugar, a
substance so liable to injury from an excess of heat, that the most complex and
expensive plans have been resorted to in order to avoid the danger of burning.
The plan has likewise been successfully adopted in several large medicinal
laboratories, and is equally valuable to distillers, dyers, and, in short, almost
every process in the arts where a steady uniform temperature is of importance.
484 EV ApORATION.
The diagram here given will show the great simplicity of the plan, and the little
chance there is of injury to the apparatus from the fire, as it comes in contact
only with a surface always protected -
by a fluid which rapidly absorbs and
carries off the caloric. The engraving
represents the apparatus as adapted to
the purpose of sugar refining. a the
evaporating pan; b. b the outer pam,
containing c, the fluid medium, repre-
sented by dotted lines, and which, for
the purposes here described, is a
modified product, by distillation of
coal tar, which furnishes vapour at the
fixed degree of 3500 Fahr. d the
breathing pipe, which, in the event of
injudicious firing, will serve as an out.
let and condenser for such portion of
3S
º
the vapour as may not otherwise be .Nº. S
§
º
condensed by the comparatively cold
surface of the evaporating pan aj e an ordinary furnace; f the ash pit.
Air, it is well known, has a great affinity for vapour, and large quantities of
water are evaporated by the process of mature; even at the temperature of the
atmosphere, wherever a large surface is exposed tº the action of the air. Taking
advantage of this fact, Mr. Cleland has contrived a new and singularly elegant
method of evaporating the aqueous parts of syrups and saline solutions. The
principle of the invention consists, in continually exposing a thin film (if the
expression may be allowed) of the liquid to the joint action of heat and air, and
by that means effecting a rapid evaporation. The apparatus consists of a con-
voluted worm of great length, heated by steam in the interior, which is made
to revolve horizontally upon its axis, partly immersed in the liquid under
evaporation, which is thereby constantly taken up by it in the thinnest possible
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stratum; and being in contact with the hot surface of the metal, the aqueous
portion of the matter is quickly formed into steam, and carried off by the sur-
rounding air, a is the boiler or vessel affording steam, which may therefore be
imagined as set over a furnace; b is a shallow vessel, containing the syrup to
be concentrated, and so placed upon the boiler as to form the top or cover to it;
c c is the worm, supported by stays upon an axis d d, which has a cavity at







EXCAVATING MACHINES. 485
each end communicating with the worm. One end of d is supported in a
stuffing-box e upon a hollow arm f which communicates with the boiler, and is
pierced with numerous small holes in that part which turns in the stuffing-box;
the other end of the axis d is supported by a solid arm g, and is open at the
extremity for the emission of the steam after it has passed through the numerous
coils of the worm. The axis may be turned by a winch h, or by a pulley k, or
receive its motion from any convenient prime mover. By this excellent
arrangement it will be seen that the steam in the boiler acts upon the bottom
of the evaporating pan, and raises the temperature of its contents; at the same
time it passes by the hollow arm f through the small apertures in the axis d
into the worm c : herein it traverses through all the turns, and escapes finally
at the opposite end of the axis into the atmosphere. The lower part of the
worm reaches to but a small depth in the syrup, and by turning the worm,
every portion of it becomes covered with the liquid, and lying in contact with
an extensive heated surface, vapour is given off, which is quickly absorbed by
the surrounding atmosphere.
EVOLUTE, in the higher Geometry, a curve, which, by being gradually
opened, describes another curve. It may be described mechanically by un-
winding a string, to which is fastened a tracer, from off a cylinder or any other
Curve.
EXCAVATING MACHINES, for digging and removing earth in extensive
excavations, have occupied the attention of many ingenious men, and various
machines for the purpose have been proposed and tried with different degrees
of success. The great difficulty appears to consist in adapting any peculiar
arrangement of mechanism which shall be capable of digging into the various
kinds of earth. Were it only to operate upon a uniform mass, like soft clay,
the task would be comparatively of easy accomplishment. Mr. G. V. Palmer,
of Worcester, appears to have devoted himself with great assiduity to the con-
struction of an efficient excavating engine, and to have expended considerable
sums in its attainment. In 1830 he took out his first patent “for a machine to
cut and excavate earth,” which we have perused at the Inrolment Office. This
machine is designed, by the application of steam power, to loosen, dig up, and
remove into a cart, earth from a canal or other cavity, and to move itself
forwards as the excavation proceeds. In principle its leading arrangement
resembles the dredging machines employed in clearing the beds of rivers and
harbours; but it has several appurtenances, such as picks, for loosening the
earth, cutters, for separating it, and scrapers, for filling it into the scoops or
elevators, which convey it into the cart by which it is moved away. The machine
is mounted upon four wheels, and gradually moves forward upon a temporary
railway as the excavation proceeds. The moving power is applied to the axis
of a fly-wheel, and to the same axis is fixed a drum or pulley, around which
passes an endless pitched chain, that gives motion to another drum or pulley,
which revolves in bearings fixed to the upper ends of two long cheeks or supports.
Around this second drum passes another endless chain, which gives motion to
a third drum or pulley, which is of a quadrangular figure, and turns on an axis
in the lower ends of the long cheeks; to this last-mentioned chain are fastened
a series of earth scoops, which are successively brought into operation in taking
up the earth. So far the machine resembles the common ballast engine; we
have therefore to describe how the several actions of picking, digging, and
projecting the earth are effected. A third endless chain is actuated by the
drum on the main axis, and gives motion to a spur-wheel, which drives another
toothed wheel attached to the fore wheels of the carriage, which gradually
advances it. By an ingenious system of levers, connected to a crank on the
main axis, a row of pick-axes, a row of cutters, and a row of scraping shovels,
are alternately brought into action. When the pickers have descended and
loosened a portion of earth, the cutters succeed, and separate it from the mass,
and this separated portion is immediately afterwards drawn forwards by the
scraping shovels into the scoops, which, by the action of the machine, are
brought into the required position on one of the sides of the revolving quadran-
gular drum; the filled scoops thence proceeding to the top of the machine by
º
ej Q
486 EXPANSION.
the revolution of the attached endless chains, discharge their contents into a
cart or waggon to be conveyed away. The same gentleman patented another
engine for this purpose in 1832. This’ consisted of an excavating cart and
plough united, to be worked by horses or other power. The cart wheels are
made considerably wider than those in common use, and the interior portion of
the ring of each wheel is made into a series of earth boxes; these earth boxes are
made to open inwards, and also towards the centres of the wheels. Underneath
the cart, immediately adjoining each wheel, is placed a plough, for raising and
turning the earth into the boxes, as the cart is moved forwards; the wheels at
the same time turning round, bring up the earth and deliver it into the body
of the cart. When a sufficient load has been thus deposited in the cart, the
ploughs are raised from the ground by means of a lever, and then the cart can
be drawn in every respect as a common cart, to the place intended for the
deposition of the excavated earth, where it is to be unloaded by withdrawing a
pair of bolts, which allow the bottom of the cart to fold downwards sufficiently
to permit the earth to escape. There are many circumstances where the appli-
cation of excavating machinery of this kind might be employed to advantage.
Under the head BARRow will be found some useful information relating to this
suoject, which we have repeatedly seen practised on the great scale.
EXHALATION is distinguished from evaporation by some writers, as not
applying to the raising of vapour in the ordinary sense of the word, but to
subtle, dry effluvia, loosened, by the action of the sun, from minerals and other
hard terrestrial bodies; that these exhalations ascend until their specific gravity
equals that of the surrounding atmosphere, where, mixing with other vapours,
they help to form clouds, and return to the earth in mists, dews, rains, &c.
EXPANSION, in Natural Philosophy, the enlargement or increase of bulk
in bodies, chiefly by means of heat. This is one of the most general effects of
caloric, being common to all bodies whatever, whether solid, fluid, or in
the aeriform state. . Metals expand in the following order, those that expand
most being placed first :—zinc, lead, tin, copper, bismuth, iron, platina.
The degree of expansion produced in different liquids varies considerably. In
general, the denser the fluid, the less the expansion; water expanding more
than mercury, and alcohol more than water. The various elastic fluids, or
gases, on the contrary, all expand equally, the expansion being about one four
hundred and fortieth part of their bulk at 320 Fahr. for every degree of heat.
But elastic fluids are capable of expanding indefinitely without the application
of heat, by the mere enlargement of the containing vessel; since whatever be
its capacity, they must necessarily be equally diffused, and press with equal
force in every part of it, the pressure being inversely as the bulk of the gas.
This property of elastic fluids has been turned to great advantage in steam
engines, by admitting steam of high pressure into the cylinder during a portion
of the stroke, and then shutting off the communication with the boiler; the

EXPERIMENTAL PHILOSOPHY. 487
expansion of the steam in the cylinder carries the piston with a constantly
decreasing force through the remaining portion of the stroke, by which mode
of working the whole effect produced during the expansion of the steam is
clear gain. Upon this subject Mr. J. Perkins, who has employed steam of
greater expansive force than perhaps any other person, observes, that there is
great economy in using very high steam expansively, and that the higher
the steam can practically be used, the sooner it may be cut off. The preceding
diagram shows (approximately) the gain in cutting off the steam at a quarter
stroke. Let the piston, which is represented by the line k l a descend to i b,
being one quarter of the stroke, with a constant force of 400 lbs. per square
inch. At this point let the steam be cut off and expand to double its volume;
when it arrives at h c it will be exerting a pressure of 200 lbs. per square inch,
producing a mean pressure of 300 lbs. per square inch through the quarter
stroke. Let the steam again expand to double its volume, and the piston will
finish its stroke at fe at 100 lbs. per inch, giving a mean of 150 lbs. through
the last two quarters; to which add 400–the
pressure during the first quarter, and 300=the gº
pressure during the second, and the sum will be
1,000, giving a mean pressure of 250 lbs. on the
inch throughout the whole stroke. It will be
seen that when the stroke is completed, the cylin-
der will be filled with steam of 100 lbs. pressure
per square inch, which will be the same in
quantity as though the steam had begun at a
pressure of 100 lbs. and continue at that pressure
throughout the stroke; but in this case the sum
of the pressure through the four quarters would
only be 400 lbs. so that by using the same quantity
of steam expansively, there is a gain of 150 per
cent. By employing two cylinders, the pistons
of which act upon cranks at right angles to
each other, a compensation is obtained for the
varying pressure of the steam ; for whilst one
piston is at its greatest power, the other is
acting with diminished power, so as to render
the force exerted nearly the same throughout
£T
the revolution, as will be seen by the diagram. ... =
The annexed figure represents an instrument %.
for showing the expansive force of steam *2. 4% S
at different temperatures. At the bottom º 2.
of a strong spherical vessel of brass is placed a ra ſo.
quantity of mercury sufficient to fill the long —
vertical glass tube above; over the mercury is w
the water to be converted into steam, by a spirit
lamp placed beneath. The long tube is sub- |
merged in the fluid, so as to nearly touch the
bottom ; on one side of this tube a thermometer
is fixed in an inclined position, its bulk projecting
towards the centre of the vessel. On the application of heat, the water is con-
verted into steam, which, by its expansive force, presses upon the surface of
the mercury, and impels it up the long tube, where its pressure is noted
upon a graduated scale; at the same time, the height of the mercury in
the thermometer shows the temperature of the steam.
EXPERIMENTAL PHILOSOPHY. That philosophy which proceeds on
experiments, and deduces the laws of nature, and the properties and powers
of bodies, and their action upon each other, from sensible experiments and
observations. The business of experimental philosophy is to inquire into and
investigate the reasons and causes of the various appearances and phenomena
of nature, and to make the truth or probability thereof evident to the senses, by
Plain, undeniable, and adequate experiments, representing the several parts of the

488 FACE GUARD.
grand machinery and agency of nature. Sir Isaac Newton, the greatest master
in the science, lays down four rules by which to guide our inquiries into
nature. 1st, More causes of natural things are not to be admitted than
are both true and sufficient to explain the phenomena; 2d, and therefore, of
natural effects of the same kind, the same causes are to be assigned, as far as it
can be done, as of respiration in man and beasts; of light in a culinary fire
and in the sun; and of the reflection of light in the earth and in the planets.
3d, The qualities of natural bodies, which cannot be increased or diminished,
and agree to all bodies in which experiments can be made, are to be reckoned
as the qualities of all bodies whatever; thus because extension, divisibility,
hardness, impenetrability, mobility, the vis inertiae, and gravity, are found in
all bodies which fall under our own cognizance or inspection, we may justly
conclude they belong to all bodies whatsoever, and are, therefore, to be
esteemed the universal and original properties of all natural bodies. 4th, In
natural philosophy, propositions collected from the phenomena by induction, are
to be deemed (notwithstanding contrary hypotheses) either exactly or very nearly
true, till other phenomena occur by which they may be rendered either more
accurate, or liable to exception. This ought to be done lest arguments of
induction should be destroyed by hypothesis. These four rules of philoso-
phizing are premised by Sir Isaac Newton to his third book of the Principia,
and more particularly explained by him in his Optics, where he exhibits the
mode of proceeding in philosophy.
EXPLOSION, in Natural Philosophy, a sudden and violent expansion of an
aerial or other elastic fluid, by which it instantly throws off any obstacle that
may be in the way. It differs from expansion in this, that the latter is a
gradual and continued power, whereas the former is always sudden and of only
momentary duration. -.
EXPONENT, in Algebra, is a number placed over any power or involved
quantity, to show to what height the root is raised; thus 2 is the exponent of
a”, and 4 is the exponent of a 4. or a wa'a. -
EXTRACT. Mixtures of several of the principles of vegetables, reduced
by decoction either to a solid, or to the consistence of paste. The word is also
applied by modern chemists to denote a peculiar substance supposed to be one
of the immediate principles of vegetables, and the same in all when separated
from any foreign admixture, except as the proportions of its constituent prin-
ciples may vary.
E.
FACADE, or FAce, in Architecture, the side of a building in which is the
principal entrance; also that exterior part of a building which is projected or
advanced beyond the main body.
FACE GUARD. A kind of mask to defend the face and eyes from acci-
dents in various chemical and mechanical processes. A guard intended to pre-
serve the face, and particularly the eyes of smiths, founders, and others, from
being injured either by the heat of the furnace or of red hot melted metal, or
of fragments of metals dispersed by the hammer, is described in the Trans-
actions of the Society of Arts. The guard is of two forms, either a veil of iron
wire-gauze of a curved form, and fastened by a hinge to the front part of the
hat; or a mask, more or less complete, with the eye-holes covered with wire-
gauze. There is not much novelty in the invention itself, but there is in its
application to persons exposed to the radiant heat of furnaces, whose eyes, it is
well known, often become much injured thereby. The great utility of it for
these purposes, has been testified by a number of persons who have recently
adopted their use, and have expressed their surprise at the trifling heat which
they, in consequence, felt upon their faces. The author of this invention, Mr.
Callaghan, received a reward for it from the Society; and we have no doubt
that its adoption by those classes of workmen for whose use it was designed,
would prove highly beneficial to them.
FAT. 489
FACETS, in Crystallography, the flat surfaces which bound the angles of
crystals.
FACIA, or FAscIA. A broad flat projecting part of a building, as the
bands of an architrave, larmier, &c.
FACTOR, in Arithmetic, a name given to the multiplier and multiplicand,
as their quantities multiplied together constitute the . or factum.
FAKE. One of the circles or windings of a cable or hawser, as it lies dis-
posed in a coil.
FAN. . A machine used to agitate the air, and cause it to impinge upon
other bodies to reduce their temperature. Those used for cooling the person
are made of every variety of form and materials that fancy can invent; but
they generally consist of a piece of paper, satin, or any other light fabric, cut
semicircularly, and mounted upon several little sticks of wood, ivory, tortoise-
shell, or the like. If the stuff be single, the sticks of the mounting are placed
on the least ornamented side; if double, they are placed betwixt them. The
paper is plaited in such a manner that the sticks may be alternately inward
and outward. In the middle of each plait the sticks are cemented; all of
which are cut exceedingly thin and delicate, and they are connected together at
the end by a single rivet, by which the fan, as it is held in the hand, may be
either folded up or expanded. The Chinese and East Indians excel in elabo-
rate carving upon the fan sticks; but the elegance and taste displayed by our
own artists upon the other parts, are unrivalled. The term fan is applied to
those small vanes or sails that receive the impulse of the wind, and, by a
connexion with machinery, keep the large sails of a smock windmill always
in the direction of the wind; see WINDMILL. Also a rotative blowing machine,
consisting of vanes turning upon an axis, used for winnowing corn. Similar
apparatus is used to decrease the speed of light machinery, by the resistance of
the air against the motion of the vanes.
Fº implies generally vegetable flour. The flour of the Parisian
bakers (which it may be presumed is chiefly, if not wholly, wheaten,) was
ascertained by M. Vauquelin to consist of gluten 10.2, starch 72.8, sweet
matter 4.2, gummy glutinous matter 2.8, and moisture 10, in 100 parts. The
farina of many vegetables consists almost entirely of starch, as is the case with
rice, arrow root, and the potatoe. The method of separating the farina from
the latter root is described with figures under the word BREAD. A patent was
granted in 1829, to Mr. Benjamin Goulson, of Pendleton, near Manchester, for
“certain improvements in the manufacture of farina and sugar from vegetable
productions.” The specification explains it to consist in a method of converting
dahlias, beets, carrots, mangel wurzel, and other roots, by the application of
acid. After the roots have been well cleaned by washing, and cleared from
their skins by rubbing or other process, they are to be sliced or grated, and
steeped in a mixture of pure water and acid (the preference being given to
sulphuric acid), in a ratio varying from two to ten pounds of acid (according to
the roots operated upon,) to a hundred weight of roots. Those which possess
the least natural sweetness will probably require the most acid. In this
mixture the roots are to be kept till they become quite soft or pulpy, when they
are to be washed with pure water till they cease to taste of the acid. They are
next to be dried in the sun or in an oven, and then be ground into flour, and
used for making bread, or other purposes for which wheaten flour is employed.
To extract the saccharine matter from roots, Mr. Goulson employs a second
dose of diluted acid, in the proportion of from two to ten pounds of the acid to a
hundred weight of the farina thus obtained, and by this means the fibrous parts
become macerated; after which the acid is to be neutralized and separated from
the saccharine portion, which is then to be clarified by the usual processes; or
the saccharine matter may, by continuing the first process, and using an addi-
tional quantity of acid, be obtained at once without first converting the roots
into flour.
FARRIERY is the art of shoeing horses and administering to their diseases.
See HoRSE-shoe.
FAT. Animal oil in a concrete state, deposited in minute cells in various
490 FEATHERS.
parts of the bodies of animals. The colour is white or yellowish ; it is insipid,
inodorous, insoluble in water and in alcohol, but it combines with alkalies and
forms soap. It absorbs oxygen by exposure to the air, and becomes rancid,
forming a peculiar acid, called the sebacic. It is decomposed by heat, producing
the sebacic acid, an empyreumatic oil, and carbonated hydrogen, leaving a
residuum of charcoal. Fat is oxidated by the acids, and it oxidates several of
the metals, when they are combined with it in the form of an ointment. Some
interesting information on the nature and properties of fat, and the mode of
separating its constituent properties, will be found under the head CANDLE. See
also So AP.
FAT is also a name given to a measure of capacity, differing in different
commodities. Thus, a fat of isinglass contains 3 to 4 cwt. ; a fat of unbound
books is four bales; a fat of wire 20 to 25 cwt ; a fat of yarn 220 bundles.
FATHOM. A measure of six feet, used to regulate the length of cables,
rigging, &c., and to divide the lead or sound lines.
FEATHERS. A general name for the natural covering of birds. Chemically
examined they are found to differ but little from hair or bristles. Mr. Hatchet
boiled some feathers for a long time in water, but discovered no traces of
gelatine; the quill is chiefly albumen. Feathers form a considerable article of
commerce, particularly those of the ostrich, heron, swan, peacock, goose, &c.
for plumes, ornaments, beds, pens, &c. Geese are plucked in some parts of
England five times a year, and in cold seasons many of them die by this
barbarous custom. Those from Somersetshire are esteemed the best, while
those from Ireland the worst; but there are exceptions to this rule, for we have
seen some Irish feathers equal to those imported from Dantzic and Hamburg,
which attain the highest price in the market from their superior strength, that
is, durable elasticity in the making of beds. Goose feathers are usually sorted
into white and grey. The latter make equally good beds with the white, but
their colour diminishes their value for sale to the extent of sixpence the pound
in the best qualities. Those feathers denominated “poultry,” which are from
turkeys, ducks, and fowls, are of very inferior value; for although they are soft
to the touch, they are too deficient in elasticity to make light or good beds.
Wild duck feathers are soft and elastic, but the difficulty of curing them from
the odour of the oil they contain, renders them less suitable than those of the
goose. Irish feathers have obtained a bad character from the large quantity of
foreign matter, particularly lime, with which they are usually mixed. A small
portion of lime sprinkled amongst fresh feathers tends to their preservation, by
combining with the oil they contain, while it also prevents the putrefaction of
the small portions of animal fibre that occasionally adhere to them; but the
Irish peasantry, or the small dealers in Ireland, with the view of impo-
sition, load them to an injurious extent, which renders the cleaning of such
feathers a work of time and difficulty. The following process of clearing
feathers from their oil, and preparing them for use in making beds, was com-
municated to the Society of Arts several years ago by Mrs. Jane Richardson,
whom the Society rewarded in consequence with the sum of twenty guineas.
“Take, for every gallon of clean water, one pound of quicklime; mix them
well together, and when the undissolved lime is precipitated in fine powder, pour
off the clear lime water for use. Put the feathers to be cleaned into another
tub, and add to them a quantity of clear lime water, sufficient to cover them
about three inches, after they have been well immersed and stirred about therein.
The feathers when thoroughly moistened will sink down, and should remain in
the lime water three or four days, after which the foul liquor should be separated
from them by laying them on a sieve. The feathers should be afterwards well
washed in clean water, and dried upon nets, the meshes of which may be about
the fineness of cabbage nets. The feathers must be from time to time shaken
upon the nets, and as they dry will fall through the meshes, and are to be
collected for use. The admission of air will be serviceable in the drying. The
whole process will be completed in about three weeks. After being prepared
as above mentioned, they will only require beating, to get rid of the dust,
previous to use.
FELLING TREES. 491
FEATHER. A term applied by engineers to narrow ribs, placed edgewise, to
strengthen framing and other parts of machines.
FEATHER-EDGED signifies any piece of work in which the edge of it is
materially reduced in its thickness.
FELLING TREES. The cutting down of trees
at the proper time, and in the best manner, requires
both knowledge and skill. Its proper season is deter-
mined by various causes, as maturity of growth, defects
in the trees, and new arrangements. Every tree that
indicates decay, ought to be immediately felled, as its
value will rapidly decrease. In all trees, there are three
stages—youth, manhood, and age. The beginning of
manhood is the fittest period for removing trees. All
plantations, when arrived at maturity, ought to be cut
down and replanted. Winter is the proper season for
felling trees that are not to be disbarked; but summer
is preferable for those of the resinous tribes. In spring
and autumn, the wood is fullest of sap; in winter and
summer the least so, and therefore it is the fittest time,
generally speaking, for levelling them. But in felling
oaks, and such as have to be disbarked or peeled, the
early part of the spring, before the leaves appear, is
found to be the fittest period, as the bark will at that
time easily separate, or “run,” as the workmen term
it. The preparatory operation to felling, is disbranching
the trees of such limbs as may endanger the tree in its
fall. In arms of timber that are very great, it is always
necessary to chop or sink in them close to the bole, and
then meeting it with downright strokes, it will be severed
from the tree without splitting. In felling the tree,
take care always to cut it as close to the ground as pos-
sible, unless it is intended to be grubbed up; and
the doing that is of advantage both to the timber
and the wood; for timber is never so much valued, if
it be known to grow out of old stocks. In the clearing
of woodland, the extirpation of the stumps and roots is
the most laborious part of the process. In British
America, the ordinary method is to allow the stumps
to remain for a number of years, according to their
size. During this period, the smaller fibres gradually
decay, and the root itself is each year removed a little
from its original position by the frost. When the far-
mer judges that time has so far produced decay, as to
render the removal of the stumps and roots practicable
by the usual means, he pitches upon the spring of the
year, when the soil has been loosened by the returning
heat; and with the assistance of four or five men, and
a couple of pairs of oxen, he effects his purpose, by a
great deal of labour, and under a disadvantageous
application of power, owing to the softness of the
ground.
In 1821, J. Mackay, Esq. of Pictou, Nova Scotia,
cut down the trees and removed the timber from a field
of ten acres. The following were the means adopted
by that gentleman for clearing the ground of the stumps
and roots, which proved so effectual, that with the
assistance of four men he cleared upon an average
80 stumps a day, and with them every root whicn could
impede the progress of the plough. A ship's winch, or movable crane, was the
machine used for accumulating a great mechanical power; this was brought into

492 FERMENTATION.
the middle of about an acre of stumps, and fastened to the largest of them. From
the barrel of the winch a chain proceeded, which extended to the farthest stump
in the piece; a number of shorter chains were also provided, each having a
ring at one end, and a hook at the other. By passing the hook through the
ring, they were fixed upon the stumps nearest to that to which the chain of the
winch was attached, and when it was raised, these chains were in succession
hooked to the leader, so that the winch was employed without interruption, till
the nearest stump was extracted. In clearing Mr. Mackay's field, five hands
were employed; two at the winch, two in fixing the chains, and one at the
stump to be raised. When the stump was large, those who attended the chains
occasionally assisted in turning the winch.
Reference to the Engraving on the preceding page.—a a the two winch handles
of the crane b b, which is chained to the largest stump c ; d d the leading
chain, proceeding from the barrel to a distant stump h, to be hooked on to the
leading chain d d as soon as it has raised the stump e, and has been disengaged
from it, so that the different stumps are raised in succession, from the farthest
to the nearest. The winch is then removed to face the next portion, and the
chain extended to the farthest it can reach, while the shorter chains are
attached to the right and left stumps, and hooked on in succession to the leading
chain, and thus continued until a whole circle round the winch has been
cleared. Should the stump to which the winch is attached be liable to give
way, it will be requisite to lash it to one or two in the rear, to secure the
purchase.
FELLOES, the curved pieces of wood, usually six or eight in number,
which, when united end to end, form the circular rim, or periphery of carriage
wheels, and into which the spokes are inserted. See WHEELs.
FELTING. The process by which hair, wool, or silk, is worked into a fabric
of firm texture, called felt, without spinning or weaving; it is chiefly employed
in the manufacture of hats, and under that head will be found details of the
process.
FERMENTATION. When vegetables and animals are deprived of life,
the elements of which they are composed exert an action on each other; some
of them enter into new combinations, others become entirely undecompounded,
and the identity of the original substance is destroyed. Fermentation is of
three kinds: first, the vinous; second, the acetous; third, the putrid. The two
first kinds are peculiar to vegetable substances; the last is common both to
vegetable and animal substances, though the change it indicates is, in reference
to animal substances, more usually called putrefaction. Moisture, and gene-
rally access of air, are necessary to fermentation; and a warm temperature
materially promotes it, while by an excess either of heat or cold it is entirely
checked.
Pinous Fermentation.—The vinous fermentation never takes place except in
substances containing sugar, and it is most remarkable in those which contain
the most of the saccharine principle. If a decoction of a vegetable holding
much sugar in solution, or saccharine vegetable juices, or simply a mixture of
sugar and water, be exposed to a heat of 700 in a vessel either uncovered, or
not entirely closed, in a short time the fluid becomes very turbid, bubbles
rise to the surface and break; mucilage is at the same time disengaged, part of
which sinks to the bottom, and the remainder rises to the top, where, with the
bubbles entangled in it, a stratum is formed, called yeast. When the quantity
of the fermented fluid is considerable, the operation goes on briskly for several
days, afterwards it becomes gradually more languid, but it is a considerable time
before it completely ceases. A fluid which has undergone the vinous fermentation
is entirely changed in its properties; its specific gravity is diminished; its
sweet taste and viscidity is gone; it becomes brisk and transparent, and has
acquired a pungent spirituous flavour. It forms beer, cyder, wine, &c. according
to the substance which has furnished the saccharine juice; and from whatever
it has been prepared, it affords, by distillation, a light inflammable fluid, called
alcohol. From the experiments of Lavoisier, it appears that sugar is converted
into alcohol by the loss of a part of its oxygen. The oxygen separated is
FERMENTATION. 493
employed to form carbonic acid gas, which produces the bubbles observed on
the fermenting liquor. A small quantity of yeast is always added to liquors
intended to be fermented, as it materially accelerates and renders uniform this
process through the whole mass of fluid.
Acetous Fermentation. When liquors are fermented for the use of the table,
they are put into casks while the fermentation is yet active; at first the bung-
hole is left open, and as yeast is discharged, the barrel is filled up with a part
of the fluid or wort reserved for that purpose; afterwards the vessel is closed.
But if the fluid be allowed to remain a sufficient time in open vessels, the
acetous fermentation comes on, which changes its taste and smell, and converts
the fluid into vinegar. This change takes place most rapidly at the temperature
of about 90°, and is promoted by changing the surfaces of the liquor by stirring
it, or pouring it from one vessel to another. During the acetous fermentation
the alcohol imbibes oxygen to a degree that converts it into an acid; and if the
liquor which has undergone this process be distilled, pure vinegar, instead of
ardent spirit, comes over. Simple mucilage will pass to the acetous fermentation,
without being preceded by the vinous, or at least the vinous fermentation is so
transient as not to be discernible. Wines deprived of mucilage cannot be con-
verted into vinegar.
Putrid Fermentation. When dead vegetables contain much saccharine
matter, and the other circumstances necessary to fermentation are combined,
the vinous, the acetous, and the putrid fermentation, succeed each other in
regular order. When mucilage is the predominant principle of the vegetable,
the acetous fermentation, above described, is the first change discoverable, the
putrid follows of course, as it is always the last, but the vinous does not appear.
When albumen and gluten are predominant in the vegetable matter, the putrid
fermentation only is apparent. We have observed the progress of a saccharine
fluid, from the vinous to the acetous fermentation; let us now trace it to the
putrid. When vinegar has been completely formed, and the warmth and
exposure to the air in which it was formed are still continued, it gradually
becomes viscid and turbid, an offensive gas is emitted, ammonia flies off, an
earthy sediment is deposited, and the remaining fluid scarcely differs from water.
Such is the change produced by putrefactive fermentation in a saccharine fluid.
When moist vegetables are heaped together in considerable quantities, their
putrefaction is attended with the production of considerable heat, their whole
texture becomes less coherent, their colour dark, and nitrogen, hydrogen, car-
bonic acid, and ammoniacal gases, begin to be evolved. When the putrefactive
process has advanced to this stage, the vegetable matter affords excellent manure;
for it is obvious that the principles of vegetables are liberated, and are ready to
nourish the seed or the root to which the manure is applied, while the warmth
with which the decomposition is attended enables the seed or root more readily
to receive the food thus offered. The putrefaction of animal substances goes on
under the same circumstances that promote the putrefaction of vegetables—
humidity, a temperature neither hot nor cold, and the access of the atmosphere;
but is distinguished by a far greater noisomeness. The presence of the air is
the least essential particular, for putrefaction goes on in vacuo, the air required
being supplied by the decomposition of water. A very small quantity of salt
hastens putrefaction, while a considerable quantity remarkably retards it, and
is therefore used in the preservation of animal food. The first indication of
putrefaction in animal substances is a cadaverous odour, their substance becomes
soft, pale, then green, blue, and lastly, a blackish brown; the smell at the same
time becomes more nauseous and penetrating, ammoniacal gas is perceived,
other gases also escape, which are of an infectious and poisonous nature; in
the end, the substance loses all traces of organization, becomes dry, soft, and
reduced to a state resembling that of an earth. The worms and insects
generally found among putrefying substances are not produced by putre-
faction, and therefore not a necessary consequence of it; life never springs
but from life, and the maggots are there because the insects from which they
spring, directed by instinct, have deposited their eggs among matter suitable
for their food.
3 R
494 FID.
FERRETTO. A substance used in colouring glass, obtained by the calci-
nation of copper and powdered brimstone, or of copper and white vitriol.
FESTOON, in Architecture, an ornament in the form of a garland of
flowers. The term is also applied to drapery, when suspended so as to form
elliptic curves, with the extremities of the cloth depending.
FIBRE (VEGETABLE). A substance of great use in the arts and manu-
factures, furnishing thread, cordage, &c. For these purposes the filamentous
parts of hemp and flax are employed amongst us; in Sweden, a strong cloth
is said to have been prepared from the stalks of hops; and in India, exceed-
ingly serviceable cordage and cables are manufactured from the husks of
cocoa nut.
FIBRIN. A peculiar organic compound, found both in animals and vege-
tables, but procured however, in its most characteristic state, from animal mat-
ter. To obtain it, we may beat blood as it issues from the veins with a bundle
of twigs. Fibrin soon attaches itself to each stem, under the form of long
reddish filaments, which become white by washing them. It is solid, white,
insipid, without smell, insoluble in water, softens in the air, becoming viscid,
brown, and semi-transparent. Fibrin does not putrefy speedily when kept
under water. It shrinks on exposure to a considerable heat, and emits the
smell of burning horn.
FID. A short and thick bar of wood or iron, which, passing through a hole cut
in the lower part of the topmast or top-gallant mast, and resting upon the trestle
trees, serves to support those masts. A most important improvement upon this
part of a ship's apparatus, is the patent lever fids, invented by Mr. Rotch, by means
of which ships may strike their topmasts, or top-gallant masts, at any moment, in
less than one minute, and fid them again in less than five minutes. The lever
fids consist of two powerful levers of the first class, resting upon iron plates or
carriages, bolted upon the upper surface of the trestle-trees, and carrying the
gudgeons or trunnions which form the fulcrums of the levers; these gudgeons
pass through circular notches cut in the upper side of the levers, and that part
of the levers which rests upon the plate being formed into the arc of a circle,
of which the gudgeons are the centre, the whole weight of the masts is sup-
ported upon the carriages, instead of upon the fulcrum, which merely serves as
a centre of motion. The operation of fidding a mast is as follows:—The mast
being swayed high enough for the short arms of the levers to enter the fid-hole
(which is defended by a very stout iron plate), the longer arms are depressed by
tackles hooked to their extremities until they attain a horizontal position, when
they are secured by lashings. To strike a mast (the top rope being rove and
made fast below), all that is necessary is to slack the lashings until the strain is
brought upon the top rope, and then to lower away. These patent lever fids
may be applied to any ship without any alteration in her tops, mast, or fid-
holes; and from the rapidity and certainty of their operations, are calculated to
render most important service to navigators in the most trying situations, where
despatch in striking a mast may be of essential consequence, as in the case of
a sharp ship grounding upon a rapidly falling tide, in gales of wind at sea in a
dark night. In the case of springing a topmast just above the cap, when
in chase, the lever fids will be found invaluable, as the topmast may be
instantly lowered until the part which is sprung is below the cap, by just
shaking the vessel in the wind for half a minute, when all will be safe, and
she may be kept on her course again. So sensible were the Lords of the Admi-
ralty of the utility of this invention, that they paid to Mr. Botch a large sum
for the use of it in the Royal Navy.
Mr. Rotch has subsequently taken out a patent for a prop for supporting
masts, by which the strain is transferred from the trestle trees to the lower
mast, just beneath the top, and acts in a direction nearly vertical. The cut on
the following page represents an outline sketch of the apparatus. , a is the top-
mast; b the lower mast; c the fish (which is a strong piece of timber fixed to
the lower mast to strengthen it) shown in dotted lines; d. the cheeks of the
lower mast, on which are fixed the trestle-trees e ; f the fid of the top-
mast; g a bolt stay to the top-mast; h, the new patent prop, bolted to the heel
FILE. 495
of the top-mast by means of an iron
plate, connected with the hinge joint
upon which it turns, the other end rest-
ing in an angular cavity made to receive
it in the fish of the lower mast; ; shows
the position which the prop takes when
the top-mast is being raised or lowered;
the curved dotted lines o o represent the 42
form into which the trestle-trees ordi-
marily become bent by the action of the
top-mast. This latter effect is owing to
the trestle-trees having to support the
whole weight of the top-mast, with its
ends resting upon the trestle-trees. To ,
the weight is to be added the force of :
the wind, which has a tendency to in- 2 .....~\"."
crease that effect in a tenfold degree, ; : :
especially when the inclined position in
which the masts of most ships are placed
is taken into consideration. If instead
of the fid and the trestle-trees having
to withstand all this force, the little prop
h be put into the cavity of the fish, it
will be seen that nearly the whole of it
is thereby thrown diagonally upon the
lower mast, which is well able to sustain
l -
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* * * ~~y_*
t.
FILAMENT. Those cztremely deli-
cate threads of animal or vegetable pro-
duction, such as are produced by the silk-worm, spiders, flax, nettles, &c.; by
the combination and twisting of which, threads, cordage and cloth are made.
FILE. A steel instrument employed for shaping or giving a smooth surface
to articles made of metal, bone, wood, &c. The varieties of files are very
extensive, being expressly adapted to numerous different trades or branches of
manufacture. There is, however, an immense variety of files which are appli-
cable to general purposes; these are distinguished by the terms of flat, half-
round, three-square, four-square, round, hand, pillar, cant, and other technical
names, which denote their transverse sectional shape ; then each of these shapes
may be single or double cut; that is, the notches or incisions made upon them
may consist of only one series of parallel lines, technically called floats, or of
two series, in which the lines or incisions cross each other diagonally. Then
again, either of these latter may be of different degrees of coarseness or fine-
ness, denominated in the trade, rough, bastard, second-cut, and smooth; the
latter term indicating teeth so fine and close as to produce upon metal a surface
nearly smooth, and requiring only the aid of the burnisher to polish it. It is
then to be understood, that each of these classes and varieties, or most of them,
are made of lengths differing from two or three inches, up to twenty inches
long. Even these are not all; there are also a numerous class of rasps, which
have jagged teeth, and are chiefly used in working bone and hard woods; also
rubbers, which are great, heavy square files, used by Smiths and others; and a
peculiar class of heavy files, chiefly used by millwrights and engineers, forming
a medium between rubbers and files of ordinary thickness; besides a great
variety of extremely delicate files of the best steel, used by watchmakers and
others. When, therefore, it is considered that the file manufacture thus
embraces several thousand distinctions, and that many thousands of families
are constantly employed in their fabrication in the neighbourhood of Sheffield,
Birmingham, and other places, an idea of the extent and importance of it may
be formed. The steel employed for files is required to be very hard, and, in con-
sequence, undergoes a longer process in the conversion, and is said to be double
converted. The very heavy files are made of the inferior marks of blistered

490 FILE.
steel; those for sharpening the teeth of saws, and the more delicate kinds, are
made of cast steel. The steel is previously drawn at the tilt hammer into rods
of a suitable size. The flat and the square files are made wholly with the
hammer and the plain anvil. Two workmen, one called the maker the other
the striker, are required in the forging of heavy files, the smaller being forged
by one person only. The anvil is provided with a groove for the reception of
bosses or dies, which are used for the purpose of forging the half-round and
three-angled files. The half-round boss contains a hollow, which is the segment
of a sphere, less than half a circle. That used for the three-angled files has a
hollow consisting of two sides, terminating in an angle at the bottom. In
forging the half-round file, the steel is drawn out, as if intended to make a flat
file, it is then laid in the die and hammered till the underside becomes round.
The steel for the triangular files are tilted into square rods. The part to form the
file is first drawn out with the hammer, as if intended to form a square file; it
is then placed in the die with one of the angles downwards, and by striking
upon the opposite angle, two sides of the square are formed into one, and con-
sequently a three-sided figure produced, which is perfected by successively
presenting the three sides to the action of the hammer. In forming the tangs
of most files, it is necessary to make the shoulders perfectly square and sharp.
This is performed by cutting into the file a little on both sides with a chisel,
and afterwards drawing out the part so marked off to form the tang. After
forging, and previous to being ground and cut, the files require to be annealed.
This process is generally performed by piling up a great quantity together in a
furnace for the purpose, and heating them red hot, suffering them after-
wards to cool slowly. This method of annealing files, and indeed any other
articles in which great hardness is requisite, is very objectionable, since the
surface of steel, when heated red hot in the open air, is so liable to oxidation.
A superior method of annealing is practised by some file-makers; and since
hardness in a file is so essential a property, the process ought to be generally
adopted. This method consists in placing the files in an oven or trough, having
a close cover, and filling up the interstices with sand. The fire is made to play
on every side of the vessel, as gradually and as uniformly as possible, till the
whole mass becomes red hot. The fire is then discontinued, and the whole
suffered to cool before the cover is removed from the trough. Steel annealed
in this way is perfectly free from that scaly surface acquired in the open air;
and if each corticle be perfectly surrounded with the sand, and the cover not
removed before the steel is cold, the surface will appear of a silvery white
colour. If the steel be suspected to be too kind, from containing too little
carbon, powdered charcoal may be employed instead of sand, or sand mixed
with charcoal. In this case the files should be stratified alternately with the
charcoal, in order that the extra conversion may be uniform. The next thing
is to prepare the files for cutting, by making the surface to contain the teeth as
level as possible. This was formerly effected by files, and the process is called
striping. The same is still practised by the Lancashire file-makers (who excel
in the manufacture), and by others not having the convenience for grinding.
The greatest quantity of files are, however, ground, to prepare them for cutting.
The stones employed for this purpose at Sheffield are of a compact and sharp
texture, of great diameter, and about eight inches broad over the face. When
used, the surface is kept immersed in water; the grinder sits in such a position
as to lean over the stone, whilst its motion is directed from him. The next
process is that of cutting the files, which is performed by means of a chisel
and hammer on an anvil. The chisel and hammer are of such a size as the
size and cut of the file require. The file-cutter is also provided with a leather
strap, which goes over each end of the file, and passes round his feet, which
are introduced into the strap on each side, in the same manner as stirrups are
used. He therefore sits as if he were on horseback, holding his chisel with
one hand, and his hammer in the other, at the same time he secures the file
in its place by the pressure of his feet in the stirrups. While the point of the
file is cutting, the strap passes over one part of the file only, while the point
rests upon the anvil, and the tang upon a prop on the other side of the strap.
FILE. 497
When one side of the file is single cut, a fine file is run slightly over the teeth
to take away the roughness, when they are to be double cut; and another set
are then cut, crossing the former nearly at right angles. The file is now
finished on one side, and it is evident that the cut side cannot be laid upon the
bare anvil to cut the other. A flat piece of an alloy of lead and tin is there-
fore interposed between the serrated surface and the anvil, while the other side
is cut, which completely preserves the side previously cut. Rasps are cut in
precisely the same way, using a triangular punch instead of a flat chisel. The
art in cutting a rasp is to place every new tooth opposite to a vacant space in
the adjoining row of teeth. The last and most important part of file-making
is the hardening them. In effecting this, three things are to be observed: 1st.
To prepare the file on the surface, so as to prevent it from being oxidated by the
atmosphere when the file is red hot, which effect would not only take off the
sharpness of the tooth, but render the whole surface so rough that the file
would, in a little time, become clogged with the substance it had to work upon.
This is accomplished by laying a substance on the surface consisting of salt dis-
solved in water, and stiffened with ale grounds or common flour. When it fuses,
this forms a kind of varnish, which defends the metal from the action of the
air. 2d. The heat ought to be very uniformly red throughout, and the water
in which it is quenched fresh and cold, for the purpose of giving it the proper
degree of hardness. And lastly, the manner of immersion is of great import-
ance to prevent the files from warping, which, in long thin files, is very diffi-
cult. After the file is properly heated for the purpose of hardening, it should
be cooled as soon as possible. The most common method of effecting this is
by quenching it in the coldest water. All files, except the half-round, should
be immersed perpendicularly, as slowly as possible, so that the upper part shall
not cool. This management prevents the file from warping. The half-round
file must be quenched in the same steady manner, but at the same time that it is
kept perpendicular to the surface of the water, it must be moved a little hori-
zontally in the direction of the round side, otherwise it will become crooked
backwards. When the files are hardened, they are brushed with water and
coke dust, the surface becoming of a whitish grey colour, as perfectly free from
oxidation as before it was heated. They may likewise be dipped in limewater,
and dried before the fire as rapidly as possible; after which they should be
rubbed over with olive oil, in which is mixed a little turpentine, and then they
are finished. To preserve them for use, or pack them for sale, they are wrapped
in stout oiled brown paper in half-dozens, the paper interposed between each
preventing any injury to the opposed teeth.
The operation of simple file cutting seems to be of such easy performance,
that it has for almost two centuries been a sort of desideratum to construct a
machine to perform that which is not only done with great facility by the hand,
but with wonderful expedition. . It is said, that a lad not very experienced in
the business, will produce with his hammer and chisel nearly three hundred
teeth in a minute. With respect to machinery, Mathurin Jousse, in a work
entitled, La Fidelle Ouverture de l'Art de Serrurier, published at La Flesche, in
Anjou, in 1627, gives a drawing and description of one in which the file is
drawn along by shifts by means of wheel-work, and the blow is given by a
hammer. There are several machines for this purpose in the Machines
approuvées par l'Academie Royale de Paris. There is also one published in
the second volume of the Transactions of the American Philosophical Society;
and a patent was taken out by Mr. William Nicholson, in 1802, for the same
object. From the knowledge, talent, and assiduity, of the last-mentioned inventor,
we may be assured that it was a very elaborate and judiciously-constructed
machine ; nevertheless it was found wanting, and never got into practical
operation; files, therefore, continue to be cut as they were a century ago.
File-cutting is an art that appears, at first thought, extremely simple, but a little
investigation of the subject will convince the reader, (as it did ourselves
many years ago, when we designed a machine for the purpose,) that it abounds
with difficulties, which, though probably not of an insuperable nature, are such
as call for unremitting study, the devotion of much time, and the incurring of
498 FILTRATION.
a considerable expense to accomplish. No man, therefore, should undertake it
who is not possessed of abundant capital, leisure, and constructive skill. In
the operations of filing, the coarser cut files are always to be succeeded by the
finer, and the general rule is to lean heavy on the file in thrusting it forward,
because the teeth of the file are made to cut forwards; but in drawing the file
back again to make a second stroke, it is to be lifted just above the work, to
prevent its cutting or rubbing as it comes back. The rough file, or a rubber,
serves to take off the most uneven part of the work; then follows the bastard
file, to reduce the file cuts or scores of the rough file, and next usually a smooth
file, to remove the scores of the bastard, and prepare the work for the bur-
nisher, if it is to be polished.
FILLAGREE WORK. A kind of enrichment on gold or silver, wrought
delicately in manner of little threads or grains, or both intermixed. In Sumatra,
manufactures of this kind are carried on to very great perfection. But what
renders this a matter of great curiosity is, that the tools made use of are very
coarse and clumsy. The gold is melted in a crucible of their own forming, and
instead of bellows, they blow with their mouths through a piece of bamboo.
They draw and flatten the wire in a
manner similar to that of Europeans. It
is then twisted, and thus a flower, or the
shape of a flower, is formed. Patterns of
them or of foliage are first prepared on
paper, of the size of the gold plate on which
the filagree is to be laid. According to
this, they begin to dispose on the plate the
larger compartments of the foliage, for
which they use plain flat wire of a larger
size, and fill them up with their leaves.
A gelatinous substance is used to fix the
work, and after the - leaves have been
placed in order, and stuck on bit by bit,
a solder is prepared of gold filings and
borax, moistened with water, which they
strew over the plate, and then putting it
on the fire a short time, the whole becomes
united. When the filagree is finished, it
is cleaned with a solution of salt and
alum in water. The Chinese make most of
their filagree of silver, which looks very
elegant, but is deficient in the extra-
ordinary delicacy of Malay work.
FILLET, in Architecture, is a narrow
rectangular moulding. In the metallic
framing of machinery, narrow moulded
slips or fillets are put in the angles, to
facilitate the casting and strengthen the
Structure.
FILTRATION. A process for freeing
liquids from particles held in suspension
in them, by causing them to percolate
through various porous substances, which
intercept the insoluble matter, but allow
a passage to the liquids, which are thereby
rendered clear and transparent. The
purpose to which filtration is most ex-
tensively applied, is the purification of
water for domestic purposes; and from
the importance of pure water as regards
the preservation of health, and from the
general complaints of the impurities
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FILTRATION. 499
abounding in the water supplied by the different companies, the subject has of
late excited much attention, and a variety of filtering apparatus have been offered
to the public, some few of which we propose to describe.
The first of these machines which we shall notice is Messrs. White and Aveline's
“artificial spring,” in which the water is made to filtrate upwards by its pressure
against the under side of a stone, the quantity filtered depending upon the area
of the stone, and the height of the reservoir from which the water descends;
but with a head of 35 feet, which can be obtained in most houses in London, a
stone of 10 inches square will filter nearly thirty gallons per hour. The en-
graving on the opposite page exhibits a vertical section of the apparatus. a
is the cistern which receives the water in its impure state; it has a ball float
and lever to keep a constant head of water over the pipe b, and likewise to
prevent any air passing down it. The pipe b b is shown broken off, that the
space between may be considered as of any required length. To the lower end
of the pipe there is a nozle c through which the pipe passes, which causes the
water to shoot up against the under surface of the filtering stone f. Through
this stone the water oozes with great rapidity, leaving the animalculae and other
impurities in the lower part or basin e of the machine, from whence they are
drawn off occasionally by the cock g, and carried away by the waste pipe h.
When the filtered water rises in the reservoir above k to a certain height, the
filtration is stopped by the rising of the float l, which by its lever or rod n, shuts
a cock o in the supply pipe. When the stone has become charged with a deposit
on its under surface, it is capable of being cleansed by the scraper s which is
turned round by means of a handle shown at the bottom of the reservoir k,
the axis passing through the stone; provision is thus made for reviving the
filtering properties of the stone whenever required, and with very little trouble.
A very old contrivance for filtering water, but which has been the origin of
most of the more recent apparatus for the purpose, consists in nearly filling the
two legs of a pipe, formed either of metal as in Fig. 1, or of wood as in Fig. 2,
with washed sand, leaving merely a space at b and e to receive the turbid water,
and another at c or f for the filtered water to run off by. The chief objection
Fig. 1.
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to these machines is, that they soon become foul, and consequently useless,
until restored by cleansing, and this task, as generally performed, is such a
laborious, tedious, and slopping one, that these filters are usually abandoned in
a short time. This objection seems to be obviated in the arrangement
shown in the cut on the following page. a is a barrel capable of being turned
round, but rendered stationary by pins passing through the extremities of their
bearings at b b, c is a bed of sand occupying about one-third of the cask; d.










500 FILTRATION.
is the supply pipe or hose, (any flexible tube,) which, conducts the turbid water
from a reservoir above, into the cask; at e is a union joint and nozle piece,
containing a sponge, which serves three purposes: it prevents the grossest
impurities of the water from
entering among the sand;
it prevents the column of
water from forcing up the
bed of sand; and it pre-
vents the sand from falling
into the pipe. The filtered
water is drawn off at f.
When the sand requires
cleaning, the pins at the
bearings of the axis are
taken out, and the winch
turned so as to bring the
union joint to the top of the
cask, previous to which the
pipe should be detached by
unscrewing. The sponge being now removed, the water may be let on freely
at top, and the barrel turned by the winch g, by which means the sand is expe-
ditiously washed, the water being let on and run off as often as necessary,
which it is obvious may be effected with so much facility, that the filtering
powers may be at any time renewed in a few minutes.
The following engraving, Fig. 1, represents an apparatus of a convenient form,
by Mr. James, of Knightsbridge. It consists of two vessels (A and B,) of stone
ware, placed upon a strong stand c. The upper vessel, which is covered,
receives the impure water in a chamber d, at the lower part of which there is
a large aperture, stopped by a sponge e, which detains the grosser impurities :
hence the water passes through a finely perforated earthenware plate into a
layer of six inches of prepared charcoal, through which the water filters, and is
Fig. 2. **-
thereby purified from any noxious smells, as well as any floating impurities; it
then passes through another perforated plate g, and is received at h into the
separate vessel, which is a stone ware cask, from which it may be drawn off at
pleasure by the cock. -
very convenient filtering machine, from its portability, is Wiss's patent
filter, which is shown in the preceding cut, Fig. 2. a is a force pump; b a


FILTRATION. 501
suction pipe, to be inserted in a pail or other vessel of water; c the pipe which
conducts the water out of the pump to the top of the vessel d, e is a receiver
for the purified water; f a cock for drawing it off; g g g, screws for separating
the receiver from the machine when required. The filtering substances used
in this apparatus are of the same description as in the foregoing ones. The
upper portion of the filter down to the letter d in the
engraving, is left vacant for the dirty water which wº-
first passes through a thin bed of charcoal, and then * *
through a bed of sand occupying the remainder of
the vessel, and supported by a perforated metal plate,
covered with a few layers of flannel.
A very simple method of freeing water from its
impurities by means of the capillary attraction of --
fibrous substances is represented in the annexed #
engraving, a is the reservoir, b the lower com- =ºsiſ #
partment, c an open tube soldered into the bottom =}|==
of the reservoir, in which is put a wick of cotton “. . . . " || || . . . . .
or wool, (the latter is best,) with one end immersed in
the bottom of the reservoir, whilst the other end
hangs down a little below it, forming a kind of
syphon. The water in rising by the capillary
attraction between the filaments deposits the gross
matter floating therein, and descends in a compara- tºº %ft
tively pure state into the vessel b, or into a jug tº answual-
placed therein.
The figures represented in page 502, are a portion of Mr. Suwerkrop's appa-
ratus for filtering and heating water. Fig. 1 shows a side elevation of the vessels
in question; and Fig. 2 is a vertical section of the same. The letters have refer-
ence to similar parts in each figure. The water is supposed to be conveyed by
the pipe a from a reservoir situated upon a higher level than the cask b, which
is divided by the partition c into two equal parts, forming thereby a double fil-
tering machine. In each of these divisions, the filtering substances and the
arrangement of them are the same. As the water flows from a higher level,
it will of course ascend through the filtering substances, and flow out at the
upper part. The first substance which it has to pass through is a circular mat
d, made by coiling up and sewing together a rope of platted horse-hair, which
detains the grossest of the impurities; from this it passes through a floor or
false bottom of wood, e, pierced throughout with numerous small holes; upon
the wooden bottom is laid first a stratum of coarse gravel or small pebbles, over
this is put a layer of finer, then a layer of finer still, and lastly, a bed of
sand f, about six or seven inches thick; from this the water rises in a tolerably
pure state; if not sufficiently purified, instead of drawing it off for use, it may
be allowed to pass through the curved pipe h into the upper division i of the
cask. The water continuing to rise, then percolates successively through the
horse-hair mat j, the perforated floor k, and the various strata of the sand and
gravell, finally flowing out of the cask, and through the pipe m, into the heating
vat n. The vat is constructed with a furnace o, and flue p p inside of it, all
made of copper, except the grating for the fuel, which is made of cast iron as
usual; copper being preferred for the flue on account of its oxidating less rapidly
than iron or other cheap materials. The heated air or gases first rise up the
neck q into the hollow sphere r, which becomes soon occupied with intensely
heated air, from whence it has little disposition to descend and escape by means
of the spiral tubes, which finally become flues for the grosser products of the
combustion; as these tubes, however, make a long circuitous course through the
tub of water. the heat is almost wholly absorbed by it. The furnace and flues
are supported and kept in their positions by stays fixed to the sides of the vat, as
shown. The three closed apertures in the cask b, Fig. 1, are for the several
purposes of washing the bottoms of the horse-hair mats, by passing water through
them downwards; and for taking out and refreshing the layers of Sand and
gravel when they have become foul by deposition from the water.
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The engraving on the next page represents an apparatus contrived by Messrs.
Williams and Doyle, for the purpose of separating the salt from sea-water, by
merely causing it to percolate through a body of sand under mechanical com-
pression, and thus to render it fresh. Could this object be obtained by such means,
the invention would doubtless be one of the utmost importance to navigation, as
it would render a store of fresh water unnecessary, thereby affording additional
stowage for provisions or cargo; but we are not aware of any experiments
proving that substances dissolved, and chemically combined with a liquid, can
be separated by filtration; we therefore apprehend that the apparatus would be
ineffectual for the object the inventors had in view, although it may prove very
efficient in freeing water from any impurities floating or suspended in it. The
following description of the engraving (which represents one of the several
modes of construction proposed by the inventors), is derived from the specifi-
cation of their patent. a is a part of the cask supposed to contain sea water;
b a tube descending therefrom, made fast by bands c e c to the filtering appa-
ratus d d, which is a strong square trunk of wood, lined internally with sheet
lead, which are cemented together to prevent the interposition of water.
This part of the apparatus is given in section, that the construction and arrange-
ment may be seen at one view ; e is the lower chamber, where the water is





































FILTRATION. 503
first received; f is a strong stool of open frame work, supported on five stout
legs, g. A plan of this stool is given in a separate figure F, the situation of
each of the five legs being marked with a g. Over this short frame is nailed a
plate of copper, pierced with numerous small holes; this plate is also shown by
a separate figure H. Over the perforated plate are several layers of woollen
cloth, or woven horse-hair i, and above these a body of sand k, filling up the
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entire trunk; on the top is placed a sliding cover 1, which is operated upon by
a strong screw ºn, working through a fixed nut m, which is supported by curved
iron arms, extending from opposite sides of the trunk. The sand having been
compressed, by the agency of the screw, into a more dense and compact mass,
is prevented from rising by the pressure of the water, which percolating through
the militate interstices to regain its level, deposits its sait, and runs out by the pipe
o in a fresh state into a vessel p placed to receive it. When the sand has become
saturated with salt, it is to be removed by taking out the screw and the press-
ing board /; the man holes r F may then be opened by unscrewing the plugs,



504 FIRE ENGINE.
when the other materials may be easily sifted. These matters being completed,
a fresh quantity of sand may be taken from the ballast of the ship, and the
process of filtration continued as before.
We shall close this article with a description of a very convenient apparatus
for filtering liquids out of contact with the atmosphere, invented by Mr. Donovan.
By means of this arrangement, alkalies can be preserved in their caustic state,
the absorption of carbonic acid by the alkali being prevented. a is a bottle of
green glass, with a funnel-shaped end inserted into
another bottle b, the junction being luted or ground to
fit closely ; the neck d of the upper vessel has a cork
tightly fitted to it, perforated in the middle for the
reception of the glass tube c, which being bent down-
wards, enters the branched neck e of the lower vessel,
thus connecting them together, and opening an air
massage between them. The funnel-shaped end of the
upper vessel has a piece of linen, loosely rolled up, placed
in it, for the purpose of filtering, but for the corrosive
acids a stratum of pounded flints should be employed
instead of the cloth. To charge the upper vessel with
the alkaline solution, the tube c must of course be
removed, and the first droppings should be allowed to
run to waste previously to the apparatus being fitted
together, that no absorption of carbonic acid may take
place in the filtered liquor. When the whole is properly
closed, the filtration will proceed without the possibility
of absorption. Now it is evident that no liquor can fall
from the upper vessel without an equal volume of air
entering it, and that none can enter the lower without an
equal bulk escaping from it. Both these conditions are
fulfilled by the connecting tube c, the air being driven
from the lower into the upper vessel at every dropping
of the filtered liquid. The whole process is therefore
conducted without the access of more air than the vessels
at first contained, and in the most cleanly and perfect
manner. The utility of this contrivance is very extensive.
The most volatile liquids, as ether, alcohol, ammoniacal
liquors, volatile oils, &c. may be filtered without loss, as the vapours cannot
escape during the operation; and by the exclusion of the atmosphere in the
filtration of a variety of fluids, other injurious effects to which they are subject
by the common process, may be entirely obviated.
FIRE, in Natural Philosophy, combustion, or the decomposition of combustible
bodies, accompanied with light and heat. The word, however, has been used
in such various senses by philosophers of different schools, that in works of
close reasoning it is now generally exchanged for that of combustion, as a term
affording a more definite meaning. Fire, under this view of the subject, is not
a substance, but a quality. It supposes two or more bodies entering into com-
bination, attended with an emission of light and heat. All these phenomena
may take place separately, but it is a compound operation, resulting from the
union of the whole, that alone produces fire.
FIRE ARMS are all sorts of arms charged with powder and ball; as cannon,
mortars, muskets, pistols, &c. See CANNoN, GUN, &c.
FIRE ENGINE. An engine for projecting water upon buildings on fire.
Buckets composed of wood, leather, or other suitable material, were the only
means employed in England and on the continent for extinguishing fires, up to
the middle or close of the sixteenth century. The earliest mention of any
description of fire engine with which we are at present acquainted, occurs in
the building accounts of the city of Augsburg, in Germany, in the year 1518.
They are there described as “instruments for fires,” and “water syringes,
useful at fires.” They are stated to have been made by Anthony Blatner, a
goldsmith of Friedburg, who, in the year above mentioned, became a citizen of

FIRE ENGINE. 505
Augsburg. These syringes appear to have been of considerable magnitude, as
they were mounted on wheels, and worked by levers; they are also represented
to have been expensively constructed. Caspar Schott, the well-known Jesuist,
states, that small engines of this description were used in his native city
(Konigshofen) in the year 1617. This writer has also furnished a short account
of a much larger one, which he saw tried at Nuremburg, in 1657. It was
eonstructed by John Hautsch, of that place, and was mounted on a sledge ten
feet long by four feet broad, which was drawn by two horses. It had two
working cylinders placed horizontally in the cistern, which was eight feet long,
four feet high, and two feet broad. It was worked by twenty-eight men, and
threw a jet of water one inch in diameter to the height of eighty feet. This
is the largest and most powerful squirting engine of which we have any record.
The English appear to have been unacquainted with the progress made by the
German engineers, or to have been very slow in availing themselves of their
discoveries; for at the close of the sixteenth century, hand-squirts were first
introduced in London for extinguishing fires. They were usually made of
brass, of various sizes, holding from two to four quarts of water each. Those
of the former capacity were about two feet and a half long, and one inch and
a half in diameter, that of the nozle being half an inch. They were furnished
with handles on each side, and every syringe required three men to work it.
One man on each side grasped the handle in one hand and the nozle in the
other, while a third man worked the piston or plunger, drawing it out while the
nosel was immersed in a supply of water, which filled the cylinder; the bearers
then elevated the nozle, when the other pushed in the plunger, the skill of the
bearers being employed in directing the stream of water upon the fire. In the
vestry-room of St. Dionis Backchurch, in Fenchurch-street, London, there are
still preserved several of these syringes, the property of that parish. They are
said to have been used at the great fire in 1666, when one of the set (originally
six) was lost, and several others much damaged. These syringes present a
valuable and interesting relic; for although the number of them formerly dis-
persed throughout the city was once very great, very few indeed of them are
now to be seen. Soon after the commencement of the seventeenth century
the Londoners perceived the convenience that would arise from fixing these
squirts in a portable cistern, and applying their power through the medium of
a lever : the fire engine thus obtained was considered a great mechanical
achievement. The advantages resulting from this arrangement were certainly
considerable, as they permitted a larger syringe to be used, which could be
worked easier, as well as much faster, than the hand squirt. This simple form
of engine, however, had many inconveniences; they projected the water by
spurts only, a cessation of the stream taking place between each stroke of the
piston, in consequence of which a great deal of water was lost, and a difficulty
was experienced in accurately projecting the stream. To be useful, it was also
necessary to place these engines very close to the fire, which exposed the
persons working them to imminent danger from the falling of the burning
buildings. That these engines were but imperfectly constructed, and deficient
in strength, we learn from a recorded circumstance, that three of them which
were taken to extinguish a large conflagration on London bridge, in 1633, and
were then considered “such excellent things, that nothing that was ever devised
could do so much good, yet none of these did prosper, for they were all broken.”
The following description of an engine of this kind has been handed down to
us by Mr. Clare, in his work on the Motion of Fluids, published in 1735.
“Engines for extinguishing fires,” he observes, “are either forcing or lifting
pumps, and being intended to project water with great velocity, their effect in
great measure depends upon the length of their levers, and the force with
which they are wrought. A common squirting engine which was constructed
on the latter principle, consisted of a large circular cistern, like a great tub,
mounted upon four small solid wheels, running upon axletrees, which supported
the vessel. A cover or false bottom, perforated with numerous small holes,
was fixed inside the cistern, about a foot below the upper edge, and about three
feet from the bottom. In the centre of the perforated cover was fixed a lifting
506 FIRE ENGINE.
pump, to the piston rod of which was attached a cross-tree carrying two vertical
connecting rods, which were simultaneously worked up and down by manual
labour, by means of two curved levers (similar to common pump handles,) on
opposite sides of the machine. During the downward motion of the piston, a
quantity of water passes through the valve on its upper surface, and gets above
the piston, and during the ascending stroke, this water is driven with great
velocity through a branch pipe provided with a flexible leather joint, or by a
ball-and-socket motion, screwed on to the top of the pump barrel. Between
the strokes the stream is discontinued. This engine is supplied with water
poured into the cistern by buckets, &c., the perforated cover before mentioned
keeping back all such matters as would be likely to choke or injure the pump-
work.” A year after the great fire of London, that is, in 1667, an act of
Common Council was passed “for preventing and suppressing fires for the
future,” in which, among other salutary provisions, was enacted that the
several parishes, the aldermen, and different companies, should provide a
certain number of buckets, hand squirts, fire engines, &c.; which shows that
these were the only contrivances then known for the purpose. We may also
infer that the fire engines were not much to be relied upon at that time, from
the greater importance attached to hand squirts and buckets. With such
inefficient means it is not to be wondered at that fires spread as they used to
do, but rather, taking into account the buildings of that period, that they were
extinguished at all. Towards the close of the seventeenth century, M. Duperrier,
in France, Leupold, in Germany, and Newsham, in England, introduced, almost
contemporaneously, fire engines of a very improved description, which soon
came into general and extensive use. The most novel and important feature
of these engines consisted in the employment of an air chamber, which rendered
the stream of water continuous and uniform; together with the equally im-
portant and valuable addition of the flexible leathern hose, of any requisite
length, invented by the brothers Jan Van der Heide, and first tried by them at
Amsterdam, in the year 1672. These contrivances enabled the stream of water
to be conveyed a considerable distance from the engine, and directed upon the
flames with the greatest precision and effect. . In the engines of Leupold,
Duperrier, and some others, one working cylinder only was employed in con-
junction with an air vessel. These machines very much resembled the common
garden engines of the present day, which are too well known to require
describing in this place. Newsham used two cylinders; and the following
description of his fire engine will be read with much interest, when it is
considered that, so perfect was his machine, at the expiration of above a
century we still find it nearly as he left it. Various convenient alterations and
improvements have in the course of this period been made in the details of this
engine, but the general character and mode of construction adopted by Newsham
have not yet been surpassed.
The following engraving represents a perspective view of Newsham's engine,
ready for working. It consists of a strong oak cistern, about three times as long
as it is broad, mounted on four wheels, and drawn by the handle a. The under
part of the cistern is cut away in front, to allow the fore-wheels to lock in
turning round: the earliest engines were not furnished with this contrivance,
but mone are now built without it. At b is an inverted pyramidical case,
enclosing the pumps and air vessel, forming a platform c, on which the fireman
formerly stood to direct the jet of water issuing from the spout or branch pipe
d. This branch pipe is attached to the air vessel by two brass elbows, the first
of which is screwed on the top of the air vessel, and the second elbow screws
upon the first by a fine screw of several threads, so truly turned as to be per-
fectly water-tight in every direction. The first elbow revolves on the top of the
air vessel horizontally, while the second elbow revolves on the first vertically;
the combination of these two motions, therefore, permits the branch pipe to be
uided in every possible direction. This contrivance, however, is now obsolete,
except in small garden engines, where it is used in an improved form. The
flexible leather hose affords such a ready and convenient method of conducting
the stream of water to any required point, that all fire engines are furnished
FIRE ENGINE. 507
with a proper quantity of it, to the extremity of which the branch pipe is
attached. At the hinder part of the engine is seen a strong leather suction
pipe (prevented from collapsing by a spiral piece of metal running throughout
its length), one end of which is screwed on, when required, to a brass nozle at
the lower end of the cistern; the other end is furnished with a rose or strainer,
and immersed in the water supplied by a pond, fire-plug, &c. To the hinder
part of the cistern is added a wooden trough e, with a copper grating (for
keeping out stones, sand, dirt, &c.) through which the cistern is supplied with
water, when the suction pipe cannot be used. An open space is left in the fore
part of the engine, also furnished with a copper grating, through which water
may be poured into the cistern. In working this engine, the handles ff, visible
on each side, are moved up and down, which gives alternate motion to the two
pumps. The working is also assisted by persons who stand on two suspended
treadles g g, throwing their weight on each alternately as they descend, and
keeping themselves steady by means of the two rails h h. The use of treadles,
however, has been discontinued for some time, and they only now remain in
a few of the oldest engines. Over the hind trough there is an iron handle or
key i, which turns the suction cock (a three-way cock) situated beneath it.
While the engine is working from water drawn through the suction pipe, the
handle ; stands in the direction of the cistern, as drawn; but when the engine
works from water contained in its own cistern, this handle is turned a quarter
round, into the position shown by the dotted lines. Between the pyramidal
case b and the fore end of the engine, there is a strong square iron shaft k,
lying in a horizontal position over the middle of the cistern, lengthwise, and
playing in brasses at each end, one of which is seen placed between the two
uprights l l supporting the hand-rails. Upon this shaft are fitted two stout iron
bars or levers m m, one at each end, which carry the cylindrical wooden handles
ff, by which the engine is worked. The treadles g g are suspended at the end
by pitched chains, and receive their motion jointly with the handles that are on
their respective sides, by means of iron double sectors fixed upon the shaft A

508 FIRE ENGINE.
. foremost sectors are seen at n, the others are contained within the upright
ox b.
Fig. 2, in the subjoined engravings, is a section of the working parts of this
engine through the cylinders, as seen on looking from the fore part of the cis-
tern towards the air vessel; oo are the working cylinders or pump-barrels; p p
the piston rods, with square holes to carry one end of the treadles; q is the
double sector connected with the piston rods by the chains before mentioned.
It will be seen that there are two chains to each piston, one passing from the
top of the sector to the lower end of the piston rod; the other from the top of
the piston rod to the bottom of the sector. The chains are riveted to the
sectors, and attached to the piston rods by screw nuts, which allow them to be
kept constantly tight. The pistons r r are formed of two round plates of brass,
smaller in diameter than the barrels, put into stout leather cups, and fastened
together by a nut, which screws on the piston-rod below the pistons; m m is a
portion of one of the levers, by which the engine is worked; the situation of the
two entrance-valves is seen at the bottom of each cylinder. Fig. 3 is another
section, taken vertically through the hinder part of the engine, showing one of
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the cylinders o and the air vessels. On the floor of the cistern is placed the
standing-piece, or sole, of cast-brass, which reaches from the nozle a through
the suction cock y, and afterwards divides itself into two branches, so as to open
under each of the barrels; one of these passages is seen in the figure, the
other is situated exactly behind it ; through these channels water is conveyed
to the pumps, either from the cistern itself, or from any place without, by means
of the suction pipes. The two cylinders are screwed down upon the standing,
or as it is frequently termed, the sucking piece, with plates of leather between
them, which makes the joints water-tight, and also forms the valves, one of
which appears at t. Each cylinder has a projecting piece cast on its lower
side, which forms a seat for the air vessel, and a communication into it, which
is closed by a valve opening upward at v. The leather valves are kept closed,
and also strengthened by a piece of metal having a tail, which passes through
the leather, and is cross-pinned under it. When the engine is at rest, all four
of the valves continue closed by their own weight; but when the engine is
working, two are opened and shut alternately. q is the sector on the shaft k,

FIRE ENGINE. 509
and g is one of the treddles in its bearing on the piston-rod; s shows the
internal construction of the air vessel. The action of this engine is exceed-
ingly simple; on raising the piston r a partial vacuum is produced in the cylin-
dero, when the pressure of the atmosphere forces the water up the suction
pipe through the cock y, along the sole, and lifting the valve t into the cylinder.
Upon the piston reaching the top of its stroke, and beginning to descend, the
valve t closes, and prevents the water, which has entered the cylinder, from
returning by the way it came ; being urged by the forcible descent of the
piston, it is driven along the communication into the air vessel, raising the
valve v in its progress, which closes again the moment the water has all passed
through. While this process has been going on, the other cylinder has become
filled with water, which is now discharged in its turn into the air vessel, and so
on continuously. On the water first entering the air vessel, a quantity of air
is expelled; but so soon as the water rises to the dotted line, the lower orifice
of the exit pipe becomes covered, and the escape of any farther portion of air
is prevented; the air is therefore gradually driven by the continued influx of
water into a much smaller space than it originally occupied, and by its elastic
force reacting on the surface of the water, drives up the upright pipe 2, along
the leather hose, and out at the branch-pipe, with so great elocity as to break
windows, &c., and throw up a jet to the height of sixty or seventy feet. New-
sham met with great encouragement, his patent being renewed for a second
term; his engines were eagerly purchased by the government, nobility, and
gentry, the 㺠parishes, and by the various fire insurance companies that
were formed about this time ; viz. the Hand-in-Hand, in 1696; the Union, in
1714; and the London Assurance Corporation, in 1720.
In the year 1792, Mr. Charles Simpkin took out a patent for an improve-
ment in fire-engines, which consisted in the employment of separate chambers
for containing the valves, instead of placing them within the cylinders and air
vessels, as was done previously. Mr. Simpkin, (afterwards of the firm of
Hadley, Simpkin, and Lott,) Long Acre, '. materially altered the
internal arrangement of the working parts, and constructed an engine much
more compact and convenient than any of its predecessors. As a travelling
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engine it was infinitely superior to any previously built; the only method of
conveying Newsham's engine about, was by placing it in a cart or waggon made
purposely for it, and many of our metropolitan readers will recollect that the
London Assurance, Royal Exchange, and Phoenix Fire Offices, continued to run
Newsham's engines in this manner to the end of the year 1832, when these and
other offices combined in forming a general fire-engine establishment, which
adopted Simpkin's form of engine. The above cut represents a side elevation of
one of Mr. Simpkin's engines, the principal working parts of which are shown
in section. The cistern a b is of oak, about seven feet long by two feet broad;
the pockets d and the upper part c are made of fir, for the sake of lightness, great











3 T
510 FIRE ENGINE.
strength not being required in these parts. The cistern is supported by strong
springs on four substantial wheels. The hinder axle is bent like a crank, to give
due play to the springs, and permit large wheels to be used without raising the
body of the engine to an inconvenient height for working. The fore carriage
locks under the front of the cistern, which is cut away for that purpose; it is fur-
nished with a pole and also shafts, to suit either cart or carriage horses...ff are the
handles working the shaft e e by means of two levers. When not in use, the
handles are kept in their present position by the forked barg. The suction-
pipe screws on to the nozle h, otherwise closed by a brass cap. There is a
screwed nozle i on each side, for attaching the delivery hose, which may be
fixed on to either side, or both sides, at pleasure. The pockets d carry two six-
foot lengths of suction pipe, and two branch pipes, one long, the other short.
The other equipments, generally about six forty-feet lengths of leather hose,
rope, crow-bar, shovel, pole-axe, saw, &c., are stowed away in convenient order
in the front and uppermost box of the engine. All being contained inside, and
nothing hung on externally, this engine is exceedingly compact, and very elegant
in appearance. The top of the engine forms an excellent seat for the firemen,
their feet resting on the pocket d, while the driver occupies the box seat in
front, guiding a pair of light horses, which will draw an engine of this kind at
great speed. At k in the sectional portion is seen the sole, or sucking-piece,
containing all the valves, and carrying the two working cylinders. At one
extremity of the cistern the three-way suction cock l is screwed to the sole k :
to the other end a brass tube is also screwed, forming a communication with
the air vessel m and exit pipe i, n is the first or suction-valve chamber, divided
into two compartments, each containing a valve, closed on the top by a plate of
cast iron, fastened down with copper screws, a piece of leather being introduced
between to make the joint water-tight. o is the second, or delivery-valve chamber,
also in two compartments, closed in the same way as the former. The valves
are brass plates, ground to fit the circular brass seat on which they rest; being
accurately ground, no leather is required to make them tight. The whole valve
is put together, and then slipped into grooves, cast in the side and bottom of
the sole for its reception. If any of these valves should fail, it is only necessary
to unscrew and remove the covering plate, when they can be got at without
disturbing the other parts of the engine. In Newsham's engine, if one of the
suction valves became deranged, the engine had to be taken completely asunder,
before the defect could be remedied. p is one of the working barrels, six inches
in diameter, with a seven-inch stroke, made of cast brass, carefully bored and
screwed down upon the iron sole k, with copper screws, an intervening leather
making the joint perfect. The piston q is of two circular brass plates, placed
in strong leather caps, and bolted together. The top of the barrels is a little
above the level of the cistern, so that when the latter is filled with water it
may not run into the barrels, and wash away the oil with which the pistons are
kept constantly covered. Projecting arms on each side of the main shaft e,
work the pistons by means of slings within the piston rod, which is forked to
the height necessary for that purpose, but ends in a cylindrical rod, working in
a guide plate above r, which preserves the parallelism of the piston throughout
its stroke. The main shaft works in brass journals at s ss. The sole k is made
so as to form an inclined plane from h to i, which causes all the water to run
out of the engine after it has ceased working. The principle of action in this
engine is similar to that already explained while treating of Newsham's, and
therefore requires no further mention here.
In the year 1793 Mr. Joseph Bramah took out a patent for a new fire engine,
with sundry improvements and additions. This engine was essentially different
in its construction from those already described. It consisted of a large
horizontal metal cylinder, having a flanch at each end, to which two end caps
or covers were screwed. These caps enclose all the working parts of the engine,
and have brass bearings with stuffing-boxes in their centres, for carrying in an
air-tight manner the working axis of the engine. Within the cylinder is
placed a strong metal partition or radius, the lower edge being joined to the
cvlinder, and the uppermost edge, which is grooved, made so as exactly to fit
FIRE ENGINE. 51 1
the circle of the latter. The axis is armed with two wings or fans, on each of
which is placed a valve opening upwards, to allow the water to pass through
them. These fans are made to move water-tight against the sides and end
caps of the cylinder, by means of leather on their edges. When the axis
carrying the fans is fixed in its place, the groove in the metal partition described
above, is filled with hemp, or some other soft material, so as to press on the
under surface of the axis, and cause it to move in a water-tight manner. The
fans being a diameter of the cylinder, divide it into two parts, the lower of
which is again divided by the radius partition into two compartments, in each
of which an aperture is cut through the cylinder opening into the suction
passages; these apertures, like those in the fan, are closed by valves opening
upwards. A vibratory motion being given to the fans by means of levers on
the axis, the capacity of the two lower compartments of the cylinder becomes
alternately enlarged and diminished; the consequence of this is, that water
becomes drawn up into the cylinder, gets above the fans on either side, and is
then forced out through the exit pipe, the stream being rendered equable by
means of a spherical air vessel placed on the top of the cylinder. This was a
novel and ingenious contrivance, and produced a very compact engine ; a
great drawback, however, upon its advantages, was the difficulty of packing
and making it water-tight in the first instance, and the still greater difficulty of
keeping it so for any length of time, if much used.
Subsequently Mr. Rowntree introduced an engine, in which he attempted to
embody all the advantages of Bramah's engine, and to avoid its defects.
Mr. Rowntree's principal improvement consisted in the employment of one fan,
a radius of the cylinder, instead of two; the vibration of the fan took place in
the lower half of the cylinder, the -
partition being placed above. Mr.
Rowntree, however, succeeded but
imperfectly with his engine, which
has been greatly surpassed by a more
recent invention by Mr. John Barton,
which is decidedly the best engine
hitherto constructed on the vibratory
principle.
The accompanying drawing and
description will convey an accurate
idea of Mr. Barton's engine, and show
the principle of action in this, as well
as in the two former contrivances.
The figure affords an end view of
Barton's engine, mounted on a suitable
cistern upon wheels. a is the cylinder,
or working barrel, of brass or iron; b
is the fan or piston, which, like
Rowntree's, is a radius, but his was
placed below the centre, while Bar-
ton's is situated above. The fan is
composed entirely of metal, on the
expanding principle, with springs and
segments, as in Barton's metallic
pistons. c c c c are four valves, all
opening upwards; d is the air vessel,
with the exit orifice at its lower part;
e is the cistern, which may be kept
full of water for immediate use on the
breaking out of a fire. This engine,
like all the former, is capable of working from a pond, &c. by means of a
suction hose, as well as from water poured into the cistern, the supply, as in
Newsham's engine. being regulated by a three-way cock placed within the
cistern. The engine is worked by the elevation and depression of the handles

512 FIRE ENGINE.
h h, connected with the axis of the fan b, which vibrates backward and forward
in the upper part of the cylinder, and delivers at each stroke nearly one-half of
its contents, and may be regulated so as to give more or less, as required. The
working of the fan or piston b, being perfectly air tight, tends to produce a
vacuum below, on that side of the cylinder a where the handle is elevated, and
the pressure of the atmosphere causes water to rush up into this space. During
this stroke the air that occupied the other side of the cylinder has been partly
expelled, and this space, on the second stroke being made, is filled with water,
while that already on the other side of the piston is forced up into the air
vessel, and thence through the exit pipes in a continuous jet.
,, . A very compact and convenient fire engine has lately been invented by
Mr. Baddeley, consisting of only one cylinder placed horizontally, and working
on the principle of De la Hire's double-acting pump. The ordinary up and
down motion of the handles, by means of a simple contrivance, causes the
piston to traverse backward and forward within the cylinder, each side being
alternately filled with water which the returning stroke expels. There are two
entrance valves lying at the bottom of the cylinder, one at each end, and two
exit valves, situated immediately over the former. The water enters at the
bottom of the cylinder, and is discharged at the top, the stream being equalized
by a globular air vessel. The inventor considers the advantages of this engine
to consist in its compact form, great strength, and durability; that it has
fewer working parts, is lighter, and has less friction than any other engine of
equal power.
Of all the engines hitherto constructed and worked by manual labour, the
floating fire engine is the most powerful. Engines of this kind generally
consist of three cylinders, working into an air vessel of large dimensions, and
are built in appropriate barges. They are put in motion by the power of from
forty to fifty men, applied to four long revolving cranks, which, by suitable
machinery, work the three pistoms. These engines will throw a column of water,
one inch in diameter, upwards of a hundred feet high. They are advantageously
employed on the river and in docks, where an abundant supply of water can
always be depended upon.
These engines, however, have been greatly surpassed by the fire engines
recently constructed by Mr. John Braithwaite, worked by steam power. The
last of this kind, the Comet, built for the Prussian goverment in 1832, had two
working cylinders ten inches and a half in diameter, with a fourteen-inch
stroke, the steam cylinders being twelve inches in diameter. When working
with a steam pressure of seventy pounds upon the square inch, and making
eighteen strokes per minute, this engine threw a jet of water, an inch and a
quarter in diameter, nearly one hundred and twenty feet high. The same
power gave two jets of seven-eighths of an inch, and afterwards four of five-
eighths of an inch, an elevation of about eighty feet. The consumption of
coke was three bushels per hour, and the average working of the engine was
calculated to be equal to the discharge of between eighty and ninety tons of
water per hour.
Numerous attempts have been made to condense a powerful fire engine into
a small compass. In this respect Capt. Fisher, R.N. appears to have been
most successful; his engine, on Newsham's principle, consisting of two five-
inch cylinders, with eight-inch strokes, and an air vessel situated between them,
was comprised within a box the size of an ordinary tea chest, exclusive of the
handles, which fixed on the outside, and served to carry the engine by. The
purposes for which this kind of engine is suitable are so few, that they have not
been very extensively used; for the local purposes only of mansions, manu-
factories, or on ship board, can they be advantageously employed.
Much ingenuity has been exercised to construct a fire engine on the rotatory
principle, but without success. An ingenious one of this kind was the invention
of Mr. Rangeley, for which he took out a patent. It consisted of two fluted
rollers, working into each other, while their opposite sides worked in semi-
cylinders, with which they were in close contact, the ends of the rollers being
similarly circumstanced; each space between the flutings came up filled with
FIRE ESCAPE. 513
water, which was discharged by the flutings exactly fitting into each other on
the descending side. In this, however, as in all the other rotatory steam and
fire engines, it was found to be practically impossible to construct an engine
sufficiently water tight to stand the great pressure to which they are subject,
without incurring an excessive and destructive amount of friction.
FIRE ESCAPE. Perhaps few subjects have more extensively engaged the
public attention, or exercised so much ingenuity, as the best mode of rescuing
individuals from death by fire. Notwithstanding the varied talents that have
been directed to this object, it is a singular fact, that no invention has yet been
Fig. 1.
produced so universally efficient as to supersede all others, or to induce the
belief that the limits of perfection have been attained. Many excellent and
ingenious contrivances have been produced, most of which will be found
embodied in the following classified description. Fire escapes may generally
be divided into three classes, viz. ladders, portable escapes, and carriage escapes.
With the common fire ladders all must be well acquainted ; they are made of
different lengths to reach a first, second, third, or fourth story window. When
of the largest kinds they are generally furnished with iron guides or hand-rails

514 FIRE ESCAPE.
at the sides, and also with a contrivance for raising them. This contrivance
consists of a short conical iron tube, jointed to one of the upper rounds or steps
of the ladder; a long pole fixes into this tube, and affords great facility in
raising the ladder. A well-made ladder of bamboo, from its extreme lightness,
combined with the requisite strength, has been considered by some persons
admirably adapted for the purposes of a fire escape. Another form of ladder,
and one that is at present very successfully employed, consists of short lengths,
from eight to nine feet long, which fit one on the other to any required extent,
by a strong, but simple joint, in the same way as scaling ladders. The advan-
tages of this kind of ladder are, great portability and convenience, with all the
practical utility of the longest and most unwieldy ladder. Mr. Gregory, whose
numerous fire escapes have attracted deserved attention, has constructed a great
variety of ladders; among them is a very pretty ladder, in two parts or lengths,
one sliding upon the other, and sustained at any required elevation by a simple
contrivance. A cradle is attached to this ladder, for the rescue of timid or infirm
persons; the whole is of a convenient size for carrying or stowage, and is very
easily managed. Mr. Gregory's patent ladders are exhibited in the engraving
on the preceding page. Fig. 1 is a side view of one of the ladders, nine feet in
length. Fig. 2 exhibits three of these ladders connected together, and applied
as a fire escape, with a light car or cradle, raised by ropes h h, working in pulleys
attached to the top of the ladder. Fig. 3 represents four of these ladders
raised, for the purpose of elevating the fireman, and enabling him to direct the
stream of water from the engine most effectually upon the fire. A set of these
ladders may be placed on a light hand carriage, or might accompany each
fire engine. On reaching a conflagration, the lower ladder is first raised, and
the feet secured in their place by a bolt passing through them and two blocks,
placed upon the engine for that purpose. The iron stays b b crossing each
other are hooked into staples fixed in the back of this ladder. The first ladder
being thus firmly fixed, a man mounts it and attaches another on the top of it;
a third, fourth, or a fifth, may in this way be added, until the required height is
obtained. When the height is considerable, two guy ropes d d are employed,
to preserve the ladders in the proper position. For this purpose the back of
the carriage is provided with two large square staples, through which the bar
e is thrust; to the ends of this bar the ropes are made fast, as shown. The
ladders are each precisely alike, so that all fit one another; they are connected
by the following simple and effective contrivance. Two long hooks or half-
staples a a are fixed on the hook of each ladder by means of an iron strap,
and riveted through; each ladder is provided with two flat steps c e at its
lower end, which drop into the two hooks and make a firm and secure joint.
Rope ladders have sometimes been employed as fire escapes; the most common
kind consist of strong rope sides, with wooden steps; circular pieces of wood
are sometimes added to the ends of the steps, to keep the ladder from walls, &c.
In Edinburgh wire chain ladders are employed with great success, being used
by men duly trained for that purpose. The principal difficulty with all ladders
of this description, is in raising them to the windows where they are required;
this difficulty has been surmounted in the rope ladder of Mr. A. Young, the
most ingenious and useful contrivance of this kind with which we are ac-
quainted. It consists of a number of rounds A, Fig. 2, (in the engraving on the
following page,) which form the steps of the ladder by being united with two
ropes B. B; these are suspended from an iron frame C, terminating in hooks
a a, which can very conveniently be lodged on the sill of a window, and thus
form a secure support for the ladder. The principal peculiarity of this con-
trivance consists in making the ladder, so that the rounds or steps can be put
together as shown at Fig. 1, forming a pole by which the frame c can be raised
up to a window from below. To effect this, the ends e of the rounds A have
ferules fitted fast upon them, and the other ends f are reduced so as to enter
the cavities of the ferules, which project beyond the end of the wood, thus
forming sockets for their reception. The iron frame c at the top has a projecting
pin d, which fits into the socket e of the upper round; this supports it at the
top. The small end of this step is inserted into the ferule of the second, which
FIRE ESCAPE. 515
is again fixed to the top of the third, and so on to the bottom. In this way a
pole is formed, as in Fig. 1, of all the steps of the ladder joined together, by
which means the hooks at the top of the iron frame may be raised up to a
window sill, and then a single jerk or pull at Fig. 1.
the lower end disunites the staves from one
another, and they assume the form of Fig. 2,
ready for ascending or descending. The side
ropes of the ladders B B are composed of
three small lines plaited together, which
method gives the means of fastening the
staves very securely to them; this is shown
by Fig. 3. A hole is bored through the stave
at the place where the rope is to be fixed,
large enough to receive one of the three lines,
and a groove is turned round outside of it at
the same place. One of the lines is passed
through this hole, the other two are taken
round in the groove so as to surround the
stave, then all three, being plaited together
make a firm connexion. The frame c at the
top has two iron rods b b fixed to its sides,
which are useful as hand-rails to any person
getting out of a window on to the ladder. The
whole rolls up into a compact bundle, and is
easily carried about. A ladder on the same
principle may also be constructed entirely of
metal, by using wire chains, and metal tubes
for the steps. Mr. Young received a silver
medal and fifteen guineas from the Society of
Arts for his invention.
Mr. Gregory constructed a very complete
rope-ladder escape, which was supported on
the window sill, parapet, &c. of a house, by a
hook of ingenious workmanship, composed of
two sides or arms, bent into a form very
closely resembling the external figure of the
human ear, from that circumstance called the
ear hook. The two sides of this hook were
held together by three horizontal iron rails or
bars. This simple, original, and effectual
a mode of attachment admits of universal ap-
plication, without any previous provision for
that purpose ; it firmly embraces alike the
thickest and thinnest walls, and when once
fixed, no downward force can separate it from
its attachment, but by tearing the hook asunder.
To this hook was attached a meat, well made
rope ladder, to which a sliding cradle was
adapted, the rope by which the cradle was
worked passing over the central bar of the ear
hook.
The next class of fire escapes, comprising
those of a portable description, is a very
numerous one, and may be said to commence
with a simple rope made fast to something
within the room, by means of which a descent
might be effected; it has been considered an
improvement to knot the rope pretty closely, and descend by alternately
changing the grasp, instead of letting the rope slip through the hand; it is but
a limited number of persons, however, who could escape by these means. It

5 | 6 FIRE ESCAPE.
has therefore been suggested to attach a sack to the end of a rope of sufficient
length, into which females, children, &c. might be put and lowered in safety,
their descent being regulated by drawing the bed close to the window, and
passing the rope once or twice round the bed post, which would generate
friction enough to make the descent easy, without much exertion on the part of
any person. Several improvements have been made upon this rude and simple
apparatus, consisting in general of a cradle in lieu of the sack, made of a con-
venient form and suitable material, and in running the rope through a pulley
hooked to a staple provided for that purpose; a guide rope is also attached to
the bottom of the cradle, which enables it to be pulled aside from flames issuing
from the lower windows, and from railings, areas, &e. In some cases the
pulley is supported by a grappling hook thrown into the window. Escapes
of this kind have been constructed by Messrs. Cobbin, Cook, Fox, Hesse,
Merryweather, Read, and some others, all similar in principle, but differing
slightly in detail. Mr. Gregory employed a stout rope, forty feet long, having
a hook at the top, and a pulley within a few inches of it; a cradle slides upon
this rope by means of two rings, one at the top and the other at the bottom of
it. Another rope, twice the length of the former, passes over the pulley,
and is fastened to the upper part of the cradle; by this rope the persons below
raise or lower it, until the whole of the inmates of the house are extricated. In
this escape the oscillations, as well as the rotatory motion, which occur in
some of the former contrivances, are both prevented.
Mr. B. Rider a short time since exhibited a simple rope fire escape, con-
sisting of a stout hempen rope sallied with worsted, having at one end a swivel
spring catch, by which it could be instantly attached to a bed post, chest of
drawers, bar of a grate, &c. Upon this rope was placed a stirrup or friction
seat, with three rings, through which the rope passed; these rings were not
placed perpendicularly above each other, but stood in a curved direction, so as
to cause considerable friction, and check the too rapid descent of the parties;
for one individual, with very little exertion, could, by means of the friction
seat, descend with another person in his lap. A contrivance was also appended,
for instantly fixing a secure noose under the arms, to be used when the friction
seat was not employed.
Mr. Davies invented a rope fire escape, possessing in an eminent degree the
essential qualities of simplicity, efficacy, and portability. It consists of a long
rope doubled, the two ends of which are secured to a strong iron hook, for the
purpose of attaching it to a ring bolt screwed to the sash frame, or a beam in
the ceiling. A number of loops, made of strong girth web, slide upon the
double rope, by means of short copper tubes or eyes; these loops are also
equipped with cloth slides. This, with a jointed rod for raising it to a window,
comprises the whole of the apparatus. The mode of using this escape is as
follows: the end of the double ropes at which the sliding loops are all collected,
is placed upon the forked extremity of the uppermost joint of the rope, a
second is added, and so on, till the necessary elevation is obtained. The persons
above having secured the hook to some suitable object, those below hold the
ropes asunder, thus forming a triangle, the apex being at the window, and the
base in the street. One of the persons above then takes one of the loops, and
passing it over his head and shoulders, fixes it under his arms; he then gets
out of the window and commits himself to the rope, down which he slides to
terra firma. As the ropes are in contact at the window, the descent is at first
rapid, but as the person gets lower, the greater divergence of the ropes i.
arrests his progress. There should be at least six or eight persons holding the
ropes, and they should be kept as wide apart as circumstances will permit; the
base should always be upwards of three yards. Females, children, &c. may be
lowered by this escape with perfect ease and safety; for, by bringing the cloth
slide on the loop close to the body, the person descending cannot quit the loop
till released by withdrawing the slide. Mr. Barnard had previously proposed
the employment of a wicker cradle sliding on divergent ropes, but this arrange-
ment is inferior to that of Mr. Davies in practical convenience and efficacy.
The principal difficulty attending the use of portable fire escapes, is in
*
FIRE ESCAPE. 5 i 7
establishing a communication with the persons in danger; the most usual
method of effecting this object is by rods about six or eight feet long, connected
either by fishing-rod or bayonet joints, or by screws, as in the escapes of Messrs.
Davies, Glass, Merryweather, and several others. The accompanying sketch
shows a series of rods connected in this manner, which
not only raise but also support a pulley upon which a cradle
is worked; this arrangement, however, requires.strong,
and, consequently, very heavy rods, and therefore cannot
be much recommended. Mr. Gregory effected a com-
munication by means of a walking stick with three
extending joints like a telescope, by which a line was
handed to the persons in danger from the window of an
adjoining house. Others have suggested the idea of
dropping a line from the tops of the houses on each
side of that on fire, which, attached to a rope, or escape
of any kind, would enable it to be raised to those
requiring its aid. Some persons have proposed to throw
a ball with a line attached, into the window from the
street, and thus form the desired connexion; this,
however, is a difficult and random mode of proceeding,
and by no means to be relied on in the time of danger.
The Edinburgh firemen use a cross-bow, and a three-
ounce leaden bullet, attached to a fine cord of the very best materials and
workmanship, 130 feet long. The bullet and cord are thrown over the house by
the cross-bow; to this cord a stronger one, is attached, and drawn over the
house by the former, and so on, until a chain ladder or escape is eventually
elevated. To act upon this plan, however, with any good chance of success,
requires the men to be regularly trained for the purpose, as they are in
Edinburgh, where they are exceedingly skilful in the management of all their
fire machinery.
Mr. Buston introduced a fire escape, consisting of a large strong canvass
sheet, with loops all round to hold on by; this being held under the window at
which any person is situated, by eight or ten persons, the party above leaps out
of the window into the middle of the sheet, which catches him uninjured.
Although this is by no means the most pleasant mode of escape, nevertheless
numberless experiments have proved it to be a safe and effectual one. As this
escape takes up but little room, and is ready for use in a few seconds, it is well
adapted to be carried by the fire engines, and most of those in London are now
provided with one of this kind.
Having thus briefly noticed the most celebrated fire escapes of a portable
nature, we proceed to describe those of a larger kind; and first of carriage
ladders. In the year 1809 Mr. John Davies submitted to the Society of Arts a
fire escape, which consisted of three ladders connected to, and sliding upon,
each other, by means of ropes worked by a small windlass; a second windlass
raised and lowered a cradle, supported by ropes passing over pulleys at the top
of the uppermost ladder. This machine was mounted upon a low four-wheeled
truck, drawn by a horse or by six men. Subsequently, Mr. Gregory greatly
improved upon this escape; he employed three ladders sliding on each other,
which, when lowered, were balanced horizontally upon a convenient frame
mounted on a light four-wheeled carriage. When in this position they are
capable of being run under low gateways, &c. with great facility. The ladders
are brought into the perpendicular position, and then raised by a small windlass
in the front of the machine, to any required height between ten feet and forty;
the ladders are then inclined towards the window, upon the sill of which the
top may be made to rest. To obtain a greater elevation than forty feet, one or
more joints can be carried up and affixed, in the manner already described under
the head of PokTABLE LADDERs. A cradle accompanies this machine, for the
assistance of those who cannot descend the ladders. Mr. Gregory's ladder escape
has been but partially employed for that purpose; as a valuable and convenient
ladder, however, it has been very extensively used by architects and others.

3 U
518 FIRE ESCAPE.
Mr. John Hudson, the founder of a short-lived society for preventing loss of
life by fire, in 1829, constructed an escape-ladder, differing in some respects
from that of Mr. Gregory, although upon a similar principle. The following is
a side view of Mr. Hudson's apparatus; a is the carriage mounted on four
r—
wheels, the front pair of which turn with their axis and handle b under the
carriage, for the facility of guiding, stowage, &c.; fſ are three ladders sliding
in grooves one within another. #. foot of the lowest ladder is hinged to a
revolving centre in the middle of the floor of the carriage; d is an arched
frame forming the quadrant of a circle, with ratchet-teeth on its edges, in
which drops a pall or click g on a cross bar fixed to the back of the lowest
ladder. The ladders usually lie in a horizontal position, as shown by the dotted
line l; the palls and ratchet-teeth prevent the ladders from falling back while
being elevated. In order to place them in the oblique position for use, they
may be elevated by hand, or more easily by turning the windlass i round the
barrel of which the rope k is wound, and the other elid of it fastened to the
ladders at about three feet above the floor. The ladders being thus brought
to the position represented in the engraving, the motion of the windlass is con-
tinued, which winds off the rope from the ladders, and elevates them succes-
sively one above the other, until they attain the greatest height. The rope k
passes through a pulley near the bottom of the lowest ladder, then over the top
of it to the bottom of the next, and then over the top of the same to the bottom
of the uppermost ladder. The pivot to which the ladders are hinged, is for
enabling them to be veered round when it would be inconvenient to turn the
carriage. The horizontal position is given to the ladders for enabling the
machine to be conveyed through low passages, &c. There is a roller n at the
top of the ladder, to prevent friction when moving up against a wall, and a
tackle fall at o for cradles, &c. *
Mr. Joseph, who entertained a strong objection to the use of a connected

FIRE ESCAPE. 519
series of ladders, submitted the following novel contrivance to public inspec-
tion:—a is a carriage capable of being drawn by two men, on which is fixed an
elevated part b, sustaining a column of wood c; within this there is a smaller
column of iron, capable of being raised by a rack and pinion, acted upon by the
winch d; on the top of this internal
column is an iron arm e on a swivel,
having a cleft at its extremity to re-
ceive the long bar or lever f fastened
to it by a bolt. The lower end of
this bar is secured to the carriage
by a pulley-tackle, which admits of
an easy and secure adjustment at
º to the upper end of this
ar is suspended the cradle, &c. in
the usual manner, with guy ropes to
guide the cradle in its descent; k is
the handle for drawing the carriage.
There is a small rope ladder at l,
and a bolt and chain at the top of
the column, for fixing the internal
pillar (which has a range of eight
feet) at the required elevation. The
pillar has a joint near its base, by
which it is turned down into the
horizontal position whenever it is
required to pass under gateways, &c.
In the year 1813, Mr. Thomas
Roberts received a reward from the
Society of Arts, for a “speedy ele-
vator and fire-escape,” of a very
complex description, on the principle
of the lazy-tongs; the same principle
has since been employed under
various modifications by numerous
persons, and most recently by Mr.
Doyle. The engraving on the fol-
lowing page represents Mr. Doyle's
machine; a a exhibiting the com-
bination of levers on one side of the -
machine; b is the frame that holds the lower pair of levers, and wherein the
moving force is applied; c the carriage on four wheels, drawn by a handle
not shown in the engraving; d is a stage or platform at the top of the machine,
on which a fireman or other individual is raised to rescue the persons from the
house on fire; at e there is a folding-bridge or gangway, to be projected into
the window of a room; at f is a toothed pinion; g is a toothed quadrant, welded
to the lowest lever-bar on one side, with its teeth taking into those on the upper
side of the pinion ; at k is another quadrant, the teeth of which take into the
lower side of the pinion; motion being given to the pinion by the winch, the
two quadrants are moved in opposite directions, and the series of levers are
simultaneously operated upon in like manner, opening and shutting like so
many pairs of shears, thereby drawing them all up closely together, or expanding
to the extent of nearly their whole length. In the accompanying cut the
machine is represented as only expanded to half the height it is capable of being
extended. On the other side of the machine, there is, of course, a similar
set of levers; they are connected to those already described, by cross horizontal
bars, the ends of which form the pivot joints on which the levers turn. The
opposite side of the lower part of the machine is also a counterpart of that
represented, and the power is connected by a common axis to the opposite
pinion. Although the principle of the movement is, perhaps, the best that
could be devised for the purpose, the practical difficulties of executing such a

520 FIRE ESCAPE.
machine on a large scale, have,
we are informed, been found insur-
mountable, an attempt to construct
one having failed.
Mr. Gregory, some few years
since, patented a “portable derrick
fire-escape,” which consisted of three
square wooden pillars, sliding one
within the other, mounted on a
convenient carriage; the uppermost
carried a pulley for raising a cradle,
&c. The pulley was elevated by a
windlass and rope connected with
the pillars in the same manner as
employed for raising his ladders.
Mr. Rose, of Manchestcr, con-
structed a fire-escape composed of
an upright frame, fronted on a
four-wheeled carriage; a second
frame sliding within the former,
carried at its top a small railed
platform or gallery, in which people
were received from the windows of
houses; or it was occupied by a
fireman with the branch of an
engine, which enabled him more
effectually to throw the stream of
water upon the fire in lofty build-
ings. The sliding frame was raised
by two chains attached to its lowest
end, and carried over pulleys at the
top of the first’frame, to a windlass
in the body of the machine ; a
ladder formed a communication
between the body of the machine
and the platform when it was in its
lowest position.
Besides the escapes already no-
ticed, there is yet another kind,
which may be very properly desig-
nated “domestic fire-escapes,” as
they are intended solely for the use
of the family in whose house they
are placed. Some of the best of
this class are those in form of a
chair, sofa, or other convenient
article of furniture, and stand in
the recess of a window, outside of
which they are soon placed, and
constitute excellent fire-escapes,
with every convenience necessary
for a safe descent. Mr. Witty re-
ceived a reward from the Society
of Arts for an admirable escape of
this kind. These machines, however, do not generally obtain, for the mass of
the people are too indifferent to this subject to provide themselves with escapes,
but rather choose to trust to the chance of obtaining external aid. Various
expedients have been resorted to, and different plans may be adopted to effect
an escape from fire, according to circumstances. Egress can sometimes be
made at the top of a house, either by a door, or by an opening made in the
g

FIRES. 521.
roof with a poker for the purpose. Sheets and blankets tied together and
fastened to the bed-post, or the bed-cords, attached in the same way, afford the
means of descending; the feather-bed, &c. thrown out, serve to break the fall
when jumping from the window as the last alternative. . With a little contriv-
ance, women and children may be lowered by means of the bed-clothes. Upon
these occasions, all depends upon the persons in danger retaining so much
presence of mind as will enable them to avail themselves of the best means in
their power; and it often happens that pressing danger develops a great deal
more ingenuity and intrepidity in individuals, than they have previously taken
credit for.
FIRES, ExTINGUISHING of. The most suitable and convenient material for
extinguishing fire is water; but when that cannot be speedily obtained in suf-
ficient abundance, it has been proposed to increase its extinguishing property
by the addition of various substances. M. Van Aken, a Swede, employed an
antiphlogistic composition of water holding in solution sulphate of iron, sul-
phate of alumine, red oxide of iron, and clay, with which he performed several
successful experiments. Some persons have recommended the employment of
simple solutions of either of the following substances—alum, common salt,
pearl-ash, and several other salts and alkalies. Other experimentalists, on the
contrary, especially M. Van Marum, have contended, with much apparent
truth, that water alone, when properly and judiciously applied, is nearly as effi-
cacious in extinguishing fire as any of the above compounds. Carbonic acid
gas, sulphuric acid gas, and steam, have likewise been suggested as applicable
to the extinction of fire; there is, however, much practical difficulty, and great
inconvenience in employing either of these
substances for such a purpose; with respect ſº |º
to the latter, some extensive and well-con- ||
ducted experiments, recently performed by || \
Mr. Waterhouse, at Preston, in Lancashire, N
have shown that steam will speedily extin-
guish moderately small bodies of flame, but
does not possess the power of preventing a
low or charring combustion, and that steam
impelled against a large fire increases the
violence of the combustion in a remarkable
degree. Water, however, is so universally
diffused, that all other modes of extinguish-
ing fires have fallen into disuse. There are
many ways of applying this fluid to the
purpose now under review, the most useful
of which we proceed briefly to describe.
The simplest contrivance for extinguishing
fires, is by means of an elevated reservoir
or cistern, a pipe from which proceeds
through all the floors of the building, with
a cock and screwed nozle in each, to any of
which a flexible hose and director can be
affixed. On turning the cock, a jet of water
rushes out with a force proportionate to the
height of the reservoir, which can be thrown
into that part of the premises where the
fire is situated. This arrangement is par-
ticularly useful in large manufactories or
warehouses. The principal advantage of
this plan, is the great facility with which
one person can apply this remedy, the
labour having been previously performed.
If the fire is so extensive as to require
more water for its extinction than is con-
tained in the reservoir, the supply must be
p

522 FIRES.
maintained by pumping. In lieu of the reservoir and system of pipes, some
persons prefer fixed pumps, drawing their supply of water from a well. The
engraving on the preceding page represents a stationary fire-pump of this
description, as erected in various places by the late Mr. Russell, of St. John
Street, London. It consists of a lifting-force pump, with an air-vessel to equalize
the stream between the strokes, placed in a deep well. The nozle of the pump
is screwed for attaching one or more lengths of leather hose, according to the
distance of the fire; the handle is forked to allow several hands to work the
pump. The advantages of this and other kinds of stationary engines, consist in
the promptness with which they can be got into action, and the certainty of
obtaining a sufficient supply of water: one disadvantage is, that their usefulness
is confined to a comparatively limited space. In some late experiments, one of
these pumps, erected at Aldgate, delivered a stream of water with considerable
force at the distance of sixteen hundred feet from the source of supply.
Of all the portable contrivances for extinguishing fires, perhaps that invented
by Capt. Manby is the most convenient, and is very ingenious. This apparatus
consisted of a copper vessel, two feet long, and eight inches in diameter, capable
of holding four gallons. A metal tube, a quarter of an inch in diameter, passed
internally from the top to within half an inch of the bottom of the vessel, fur-
nished at the top with a stop-cock and jet-pipe one-eighth of an inch in
diameter. Three gallons of a saturated solution of º, in water being
put into one of these vessels, the jet-pipe was removed, and a condensing
syringe afforded in its place; as much air as possible was then pumped into the
space remaining above the fluid : the stop-cock was then turned, and the con-
densing syringe exchanged for the jet-pipe. In this state the apparatus formed the
well-known artificial fountain in pneumatics; on turning the cock, the elasticity
of the condensed air reacting on the surface of the fluid, forces it out at the
nozle in the form of a violent jet. Six of these vessels were placed in a light
hand-cart, with which a man could run at a good speed. On reaching the fire
the man takes one of the charged vessels from the cart, and slings it in front
of him by a strap passing over his shoulders; he then enters the build-
ing, and placing himself as close as possible to the fire, turns the cock, and dis-
charges the contents of the vessel on the flames; by the time the first vessel is
expended, others will have been conveyed to the man, who discharges them in
succession. All fires, even the greatest, have small beginnings, and when early
discovered, are easily kept under or suppressed. Capt. Manby's fire-cart appears
well adapted to check the progress of fires, if not by entirely suppressing them,
yet by keeping them within the range of easy extinction by more powerful
means, which cannot be so expeditiously applied.
Fire-engines are now common in every civilized country; the several kinds of
these useful machines having been already fully described, it will only be neces-
sary in this place to offer a few practical remarks on their management. In
bringing up, placing, and setting a fire-engine to work, great judgment is requi-
site, and much will always depend upon the acquaintance of the parties employed
with the duty they have to perform. Great activity is required in combination
with skilfulness; six good hands will, at any time, get a large fire-engine to
work through two or three forty-feet lengths of hose in about two minutes,
supposing water to be at hand. An engine being set to work, its efficient per-
formance will depend entirely upon the manner in which the stream of water
is directed. The old method was to throw the water into the windows at ran-
dom; latterly, however, a more rational mode of operating has been adopted,
and one, the advantage and efficacy of which was strikingly exemplified by the
experiments of M. Van Marum, before alluded to. The only successful mode
of using a fire-engine, is to take the director or branch-pipe into the building, as
near as possible to the fire, and be sure that the stream of water strikes directly
upon the burning materials; this cannot be too often or too anxiously inculcated
on every person using a fire-engine. Every other method not having this for
its fundamental principle, will, in nine cases out of ten, utterly fail. When the
water is thrown into the building hap-hazard from the street, it is impossible to
say if any of it touches the parts on fire or not, unless the flames appear at the
RIRES. 523
windows. On taking the hose and branch pipe inside the building, besides the
advantage of the water striking directly upon the fire, there is a great saving in
the article of water itself; the whole quantity thrown by the engine is usefully
and advantageously applied, and no more is thrown into the building than is
absolutely necessary to extinguish the fire. If, on entering an apartment, the
flames are found to cover a consider-
able space, the thumb should be
placed partly over the aperture of
the nozle, which will spread the
stream of water according to the
F.". applied, so as to wash a
arge surface at once. In encoun-
tering fires at close quarters in this
manner, much inconvenience arises
from the smoke and heat; to avoid
the former, by far the most annoy-
ing and dangerous of the two, it be-
comes necessary to kneel or lie
down, so that the fire may be clearly
seen and the water thrown upon it.
While in a recumbent posture, a per-
son will generally be able to respire #
aircomparatively pure, though stand-
ing upright, suffocation would be
inevitable: the purest air is always
the lowest.
Mr. Roberts, a miner, invented a
“hood and mouth-piece,” which
enabled the wearer to enter premises
when on fire, through the most dense
smoke, and rescue human life and
property, or apply the most eligible
means for extinguishing the flames.
Mr. Roberts's apparatus is shown in
the accompanying engraving, which
is a side view, as it appears on the
wearer. It consists of a leather cap
or hood a, which entirely covers the
head and face, with strong glasses
before the eyes. The lower part of
the hood is padded with soft cotton,
covered with wash leather, which
being drawn tight round the neck
by a strap and buckle, excludes the
surrounding air. The upper part of
the proboscis b is of sufficient capa-
city to include the nose and mouth
of the wearer, and forms the channel
through which he respires. A trum-
pet-mouthed orifice is formed at c,
provided with a good cork stopper,
which is secured by a small brass
chain; the use of this appendage is
to afford a ready relief to the lungs,
without taking off the hood when
the wearer goes to the door or win-
dow of a building on fire, for the
purpose of respiring a purer atmo-
sphere, or to consult with persons on the outside. Below this part is attached,
by means of an union joint, a flexible tube d, about two feet six inches long,
#
©
||
l
º


524 FIRES.
and terminating in a funnel five inches in diameter, in which is contained a
sponge saturated with water. The flexible pipe is kept distended by a spiral
coil of wire, and the straps e e are for the purpose of buttoning it to the dress
of the wearer, so as not to encumber him, or impede his exertions. The opera-
tion of the apparatus is as follows:—The gaseous and other noxious matters
-
which exist in the apartment, are, by the act of inspiration, obliged to pass
through the funnel of the tube, where they are absorbed and neutralized by the
liquid contained in the sponge, and the air is sent up to the lungs in a pure
sate. The efficacy of the apparatus
has been repeatedly proved, in the
presence of numerous scientific indi- Fig. 2.
viduals, amidst the most dense smoke, #TE:
arising from the combustion of wool, IE, .
wet hay, wood shavings, &c., besides Tiº K. º
large quantities of sulphur, in tem-
peratures varying from 90 to 2400 of
Fahr.
To obviate, in some measure, the
necessity for entering the apartment
in which the fire is raging, Mr.
George Dodd invented and patented
an ingenious contrivance, consisting
of a peculiar arrangement of levers
and joints connected with the hose
of a fire-engine, by which the operator
may direct a jet of water to any unseen
part of the interior of a ship or house on
fire. This will at once be understood
on reference to the above engraving,
Fig. 1, wherein a person at a is point-
ing to the spot where the fire is situ-
ated; the operator b then directs
the lever c he holds, so as to point
to that part; this movement causes
the nozle d to point to the same
place, and, consequently, the utmost
effect in extinguishing the fire is pro-
duced, which is, of course, greatly
accelerated by excluding the admis-
sion of fresh air. The annexed Fig. 2
exhibits a part of the above on a
larger scale, showing more exactly
the construction of the apparatus by
which these effects are produced; e
is the branch pipe of a fire-engine, of a peculiar form, the hose being screwed
on at f. If there is no bull's eye in that part of the deck where it becomes




FIRES, 525
necessary to insert the apparatus, the carpenter would be directed to strike out
a hole, as shown at g, through which the branch would be let down to the
required position, when it would be made fast by turning the screw h in the
ferule i, the aperture below being entirely covered by a large flanch at the
bottom of the ferule, as represented. The lever c moves upon a fulcrum, or
centre-pin, at the upper end of the branch pipe e, not affixed to the pipe itself,
but to another ferule fixed thereon. To this lever is attached, by another
centre-pin k, the long bar l l, which is connected by a pivot-joint to the nose
pipe d. It will now be seen, that as the distance between the two joints in the
nose pipe is the same as the distance between the two joints in the lever c, a
corresponding motion will be produced when operated upon in any direction,
upward, downward, horizontally, or obliquely; and as the connecting rod l is
perforated with a number of holes, it may be attached in any part of its length
to the lever c, so that the jet may play close under the deck, or far from it.
There are several other modifications of the apparatus to suit different circum-
stances, but the above explains the principle of action of the whole, which
appears calculated to prove useful in stopping fires on ship-board.
FIRES, PREVENTION of. Among the various modes which have from time
to time been proposed for this purpose, the most useful and important are those
relating to the manner in which buildings are constructed. The general prin-
ciples to be attended to are simple and briefly stated, viz. the use of incom-
bustible materials to the greatest possible extent, and the placing of those
necessarily inflammable in situations and under circumstances the most
unfavourable for combustion. The incombustible materials commonly employed
in building are stone, brick, and metal; the combustible is timber, in all its
various forms. Many ingenious expedients have been resorted to for the
purpose of rendering wood fire-proof; solutions of muriate of ammonia, muriate
of soda, sal ammoniac, borax, alum, and several other salts and alkalies, have
this property to a certain extent. Professor Fuchs, member of the Academy
of Science at Munich, invented a composition for making wood fire-proof,
which consisted of ten parts potass or soda, fifteen parts fine silicious earth,
and one part charcoal, mixed together with water. This composition, applied
to the surface of wood, forms a vitreous coat, which effectually resists the action
of fire. After some decisive experiments had fully established the efficacy of
this plan, the Royal Theatre at Munich was protected by the application of
this composition ; the surface covered was upwards of four hundred thousand
square feet, and the expense, it is said, did not exceed five thousand francs.
The following is an English composition for the like purpose:–one part, by
measure, of fine sand, two parts wood ashes, and three parts slacked lime,
ground together in oil, and laid on with a painter's brush, the first coat thin,
the second thick. This forms a very strong and adhesive coating, which is
both fire and water-proof. There are, in general, however, many practical
objections to the use of these preventives; and the more feasible method of
obtaining the desired security appears to be in the judicious selection and
skilful disposition of the materials most commonly employed. Bricks form the
staple material for building in most of the towns in this country, and with them
the external walls are usually constructed ; where due attention is paid to the
prevention of fire, the partitions will be of the same material. If circumstances
permit it, brick arches will also be used for supports. When it is desirable, for
the purposes of trade, &c. to support the walls on brestsummers, those of cast
iron are employed. Pillars of the same material are also frequently used with
advantage to support fronts of considerable length. In this way the skeleton
or frame-work of a building is easily completed in a fire-proof manner. The
next thing, then, to be attended to, is the floor; and here we find caution
extremely necessary, as the security of the building depends greatly upon the
manner in which the floors are constructed. In dwelling houses, floors of wood
are essential to an Englishman's notion of comfort; nor is there any real
difficulty in obtaining them of this material perfectly compatible with the end
now under consideration. There is a particular description of floor occasionally
used in Edinburgh, which, although not absolutely fire-proof, is certainly almost
3 x
526 FIRES.
practically so. It is composed simply of plank, two and a half or three inches
thick, so closely joined and so nicely fitted to each other and to the walls, as to
be completely air tight. Its thickness, and its property of being air tight, will
readily be observed to be its only cause of safety. A floor of a somewhat
similar kind has been employed in the meighbourhood of Manchester with
success; the planks are about three inches thick, jointed and ploughed on the
edges for the purpose of receiving slips of iron called tongues, that enter some
distance into each board; this makes a tight and substantial floor, which, as
well as the former, should be laid on iron joists. Great protection is capable of
being given to boarded floors, by using a strong fire-proof cement for the ceilings;
the plaster at present employed is so to a certain extent, but this may be greatly
improved. If a fire occurred in a room protected in this manner, the chance
is more than ten to one that it would burn itself out before it could ignite the
building. It would be very difficult to set fire to the floor, from the natural
tendency of flame and heat to ascend; it would be still more difficult to ignite
the ceiling, from the resistance offered to the flames by cement, iron joists,
and, finally, by the closeness of the flooring. If the fire should not, however,
be entirely repulsed, still its progress would be so greatly retarded as to afford
plenty of time for the successful application of the usual modes of suppression.
Before quitting this subject, however, there are some kinds of floors veritably
fire-proof, which could not with propriety be omitted. At Manchester, fire-proof
floors have been constructed in the following manner:—the columns and beams
are of cast iron, and are firmly secured in their places with wrought-iron bars
that traverse from beam to beam. Upon a margin underside the beam spring
arches of brick work; these are filled to a level on their upper side with hard
rubbish, and then covered with flags or tiles.
Mr. Frost, builder, of Bankside, London, has succeeded in forming excellent
floors and roofs to houses, of hollow earthenware tubes and cement, so combined
as to form a floor as strong as one of timber, but perfectly fire-proof. The
hollow tubes are square in the section, and are made of brick earth, prepared
by machinery in a very superior manner; they are placed in strata in opposite
directions, and cemented together. The floor or flat roof thus produced, is, in
effect, one solid flag stone of the size required, but not one-fifth the weight of
stone. The cement which Mr. Frost employs is thus formed: chalk is ground
fine in a mill, and, as it is ground, mixed with water, which carries its lighter
particles to a reservoir. Clay is ground at the same time, and, mixed with
water, is conveyed in the manner before mentioned. This combination
of chalk with about thirty per cent. of clay, is drained, and left to evaporate
to dryness. The mixture is then broken up, burnt in a kiin, and after being
ground to powder, it is closely packed in casks; in this state it will keep for
any period, and may be sent to any distance. Mr. Frost's floors have many
recommendations, and his cement affords a very convenient mode of protecting
various parts of buildings from the action of fire.
Mr. Farrow, of Great Tower-street, London, took out a patent a few years
since for a new method of constructing fire-proof buildings, a large model of
which was erected in Mark-lane, for public inspection. The walls are of coarse
brick or stone, built in the usual manner. The joists are of wrought iron; they
are formed with a lateral projecting flange on each side, upon which are laid,
from joist to joist, a series of flat stones, and of sufficient thickness (from two
to two and a half inches,) to lie flush with the upper edge of the joist, forming
a level floor of stone interlined with iron : it may be used in this state, or
covered with planks, according to the purposes of the apartment. The ends
of the joists are turned down and let into bond stone laid upon the walls, and
cemented or run in with lead, which, with the weight of the walls, continued
upward, takes off the elasticity of the iron, so as to enable the joists to carry
almost any weight, and at the same time ties the walls together in such a
manner as to render it impossible for them to separate. The boarded floors are
grooved into the edge of the joists about half an inch, and when dowelled, will
require very little fastening down. But where it is necessary, a stub is let
into the stone floor, and screwed to the edge of the board; there are, therefore,
FIRE-PLACES. 527
no mails necessary, nor any other fastenings visible when the floors are finished.
The under part of the stone is stabbed or made rough, so as to form a good key
for the ceiling, therefore no laths are necessary, and the whole floor occupies no
more than from four to five inches in depth. A roof is the same; and, being
covered with mastic, is, according to the statement of the patentee, the cheapest
roof ever invented, with the important advantages of being fire, air, and water-
proof. These floors have been successfully employed in some sugar refineries,
and other premises liable to accident from fire, and are admirably adapted to
prevent this calamity. Having thus briefly described some of the most important
facts relative to floors, we proceed to state that the most material part of all
buildings, so far as prevention of fire is concerned, is the staircase, for this part,
above all others, acts as a conductor, and greatly assists the spreading of the
flames. When a fire is discovered before it has gained possession of the stairs,
its suppression is comparatively easy ; but the staircase once on fire, there is
but slight chance of saving the building. Effectually to prevent the spread of
fire, therefore, it is absolutely necessary that the stairs should be wholly com-
posed of some incombustible substance. In many places on the continent the
stairs are always of stone, which is quite sufficient to account for the speedy
manner in which conflagrations are extinguished by the fire associations of
those countries, where, although the number of fires are considerable, the
amount of damage is usually very small. Nothing gives a more elegant appear-
ance to a house than a clean well-proportioned stone staircase, and this material
is by far the most eligible for the purpose; economy, however, may dictate the
employment of a cheaper material without prejudice to the effect. In ordinary
dwelling houses it is necessary that the roof should be as light as practicable,
nor is it very essential to bestow fire-proof qualities on this part; but in manu-
factories and public edifices it becomes desirable to render the building fire-proof
throughout. This is done in some cases by using cast-iron framed roofs, with
metallic or other covering. At the New Palace, in St. James's-park, the builder,
Mr. John Richardson, of Spencer-street, introduced fire-proof floors and roofs,
composed of hollow earthen coombs or pots, invented some thirty years before,
and first used at Knight's Hill, near Dulwich, the seat of Lord Thurlow. The
coombs are arranged in arches, springing from stone abutments resting on the
flanges of the iron girders; the spandrils of the arches are filled up with brick
work, forming a level roof, which is covered with hot cement. This cement is
composed of chalk, coal tar, and sand. The first coat being levelled with heated
irons, is suffered to harden ; a second coat is then applied, and the slates
embedded in the cement while it is hot. Woeful experience has shown that
the defective construction of chimneys and setting of stoves have been a fruitful
source of fires; a slight attention to these points would be sufficient to remedy
the evils arising from this cause. Lateral openings are sometimes imprudently
suffered to remain, communicating between the chimney and sides of the
room ; these places in time become filled with soot, which a falling spark
ignites, and sets fire to the apartment. No beam should on any account be
permitted to enter a chimney; this was too common formerly, and has caused
the destruction of many buildings. An act of parliament, passed some years
back, for regulating buildings, and so preventing the spread of fires, has tended
in some degree to remedy the evils just referred to ; this act, however, contains
many incongruities, and it stands greatly in need of that revision which it is
expected very soon to undergo. It would doubtless be both useful and inte-
resting to follow out the subject of fire prevention, and detail the cautions
necessary to be observed in the application of fire-heat, to manufacturing
processes, as well as the management of fire and light in the arrangements of
domestic economy. The limits of this work, however, will not permit us to
extend the present article; but in many of those that follow we shall have
occasion to make some observations on the subject.
FIRE-PLACE is a general term given to the brick, stone, and iron-work,
which constitute the apparatus for heating the apartments of dwelling-houses,
and for performing culinary and other domestic operations, to which the various
names of stoves, stove-grate, grate, and range, are given; but as it would be
528 FIRE-PLACES.
uninteresting and useless to explain, in this place, the bath, pantheon, rumford,
and other common open stoves and ranges, with which every eye is fami-
liarized, we shall confine our notice to the leading features, (stripped of all
ornament), of those deviations from the ordinary apparatus, which are regarded
as improvements upon the before-mentioned. It has been remarked, that
Englishmen, who boast so much of their firesides, and who are the greatest and
most skilful manufacturers of iron work in the world, are generally the worst
provided with the means of comfortable warmth of any civilized nation.
The mode almost universally adopted for increasing the temperature of our
apartments by the common open stoves, supplied, as they are, with air drawn
from around the chilled persons of its occupants, is perhaps as wasteful and
inefficient as could be designed. Full nine-tenths of the heat generated in
the grate is rapidly conducted away up the chimney into the atmosphere, while
the remaining feeble tenth is radiated into the apartment. The introduction
of the register stoves, about thirty years ago, undoubtedly effected a considerable
mitigation of the evil just mentioned. These stoves, filling up the entire
opening of the fire place, and being provided with a flap door at the upper part
of the back, which can be opened and shut, more or less, according to the state
of the fire, and the emission of the smoke, check in some degree the current
of cold air which is constantly rushing to the fire-place to fill up the vacuum
in the chimney, and support the combustion of the fuel in the grate. When
there is only a little, or a very clear fire in the grate, the flap door may be
almost closed, in which state it prevents the falling of soot into the apartment.
There is, however, this objection to such stoves being made entirely of metal,
which, from its great conductibility, is not so economical with respect to the
fuel as the following, and some others of a very humble kind.
Irish Stove.—Mr. Buchanan, in his Essay on the Economy of Fuel, relates,
that on landing in Ireland, he was much struck with the excellent construction
of the fire-grate in the room of the inn where he lodged. He at first thought
it was an invention of his landlord's, but on proceeding on his journey, he
found the same kind of grates common in that part of Ireland. Fig. 1 repre-
sents a front elevation, and Fig. 2 a transverse vertical section of one of these
fire-places, which appear well calculated to remedy the smoking of chimneys,

Fig. 1. Fig. 2. |
H |

:
and, at the same time, to lessen the consumption of fuel. The fire room is
wide and shallow, presenting the greater surface of fire to the room, and
thereby radiating the greatest quantity of heat into it. The upper portion
of the chimney recess is partly closed by an upright slab of fire stone, in
which is cut an arch. The back wall is formed of fire stone, or fire brick, into
an oval niche, and the throat of the chimney is made very small to increase
the velocity of the air, and thus enable it the better to carry off the smoke.
Birmingham Stove.—The stoves in common use in Staffordshire and War-
wickshire, although not so elegant as those made in London and Nottingham
FIRE-PLACES. 529
for the same class of rooms, are far, more judiciously disposed for diffusing
warmth. Instead of the usual recess in the brickwork for the reception of the
stove, the wall is built up in front from the ground to the mantel, and flush with
it, leaving only an aperture of eight or nine inches square for the passage of
smoke into the chimney; this is situated just above the back of the stove,
which is placed against this wall, projecting its whole depth entirely into the
FOOII).
Open Fires.—There is, from long custom, so great a desire among all ranks
in England to see the fire that warms their apartments, that the most con-
venient, cleanest, and cheapest methods of heating them, are sacrificed to
this single circumstance. Accordingly, persons who attempt the improvement
of stoves are compelled to endeavour to combine what appears to be irrecon-
cilable, namely, the appearance of a bright open fire, with an economy of fuel,
regularity of temperature, and without producing a draught through the apart-
ment. Of the various contrivances in which the attainment of these proper-
ties have been attempted, there are but few worthy of notice.
Sir George O. Paul's Stove.—This stove may, at pleasure, be made either an
open fire-place, or a close stove, heating the room by the radiation of the heat
from its front wall; and when thus acting as a close stove, it serves as a ven-
tilator of the apartments with which it is connected. The fire-place is of the
ordinary dimensions. Folding doors are made to close the fronts of the ash-
pit, and to fall back against the hobs; other folding doors are made to close the
front of the grate, and to fall back against the sides. The top of the fire grate
was also provided with a floor, which formed a back when open, but when shut
down horizontally, left only a small cavity, and produced a strong draught. It
was supplied with air by tunnels underneath the hobs. Although the utility of
this stove was satisfactorily proved in Gloucester gaol, and other places, its
clumsy inelegant appearance prevented an extensive adoption. Mr. Marriott
has, however, so modified it as to remove the above-mentioned objection, and
has recently brought it before the public in the following form. The shadowed
compartments a and b are recesses
just of sufficient depth to admit of
the doors e e and f f, when folded
back, to lie flush with the other
parts of the front of the stove, as
is the case with those marked e
and d. We have thus arranged
them in the drawing merely to
render the matter quite clear to
the eye, not that such positions of
the doors are peculiarly eligible,
(nevertheless cases may be ima-
gined wherein they would be so,
such as screening particular objects
from the influence of the fire, or
increasing the combustion of a
particular part of the fuel, by
altering the direction of the cur-
rent of air.) In lighting a fire, or
in replenishing one that is low, the combustion is greatly excited by shutting
the four upper doors, which act as a “blower.” On the contrary, when a fire
burns too rapidly, or is not much wanted, the four lower doors may be shut,
which will damp it immediately, yet allow a great portion of the heat to radiate
into the room. On retiring to bed, or wishing to leave the room in perfect
security from fire, all the doors may be closed, when the fire will infallibly go
out for want of draught. To keep in the fire, and yet leave the room in safety,
or to prevent the radiation of much heat and light in a room (often desirable
in the chamber of the sick), the doors may be placed thus TV VT. For such
chimneys as occasionally return their smoke, or in which the draught is feeble,
these stoves will, we doubt not, be also found very convenient and advantageous.

530 FIRE-PLACES.
Pycroft's Patent Fire Stove.—Mr. Pycroft, of Rolleston, near Burton-upon-
Trent, took out a patent for improvements in fire-places, in 1831, the principle
of which consists in connecting with the fire stove a chamber for hot air, to be
admitted at pleasure either into the apartment where the fire is situated, or into
one adjoining thereto. The hot-air chamber extends from below, up behind,
and on each side, and over the top, under the mantel. The air passes into the
chamber by a series of registers situated below the fire, and when heated,
passes out into the chamber by a series of registers situated over the fire.
When it is intended, for the sake of ventilation, to receive the air to be heated
from the external atmosphere, instead of from the room where the fire is situ-
ated, the registers below the fire must be closed, and a communication opened
between the external air and the lower part of the chamber ; and when it is
intended to throw heated air into an adjoining apartment above the fire, the
registers are to be closed, and a communication opened between the upper part
of the chamber and the apartment to be heated. For the purpose of exciting
a draught at pleasure, and of preventing any smoke issuing into the room, a
hood or blower is hinged to the upper part of the grate, which may be brought
out towards the front or top bar of the fire. Behind this is another hood or
blower, which is raised or lowered by a knob passing through the first; this
inner hood is provided with angular side-flaps, which, when the blower is
brought down and projected forwards, inclose the side of the fire. This stove
has likewise a flap valve at the back, acted upon by a handle in front, by which
the flue or throat into the chimney may be regulated in its dimensions, and the
draught increased, diminished, or entirely stopped at pleasure.
Cutler's Patent Stoves.—This invention,
when first brought before the public in 1815, 2-2----...s.,
met with considerable patronage; but it is now, -; , ,” `s,’s
we believe, but little used, owing to some N
difficulties of a slight description, for which 3.
no sufficient remedy has yet been provided.
The spirit of enterprise which originated the
invention received, we have been informed,
a severe check, by the numerous and com-
bined attempts of rival manufacturers to invade
and destroy the patent right, which is now
expired. The principle of the contrivance is,
however good, and will probably, under able
management, become a valuable apparatus.
The invention consists in the construction of
stoves and fire-places in such a manner as
that the fuel necessary for combustion shall
be raised and supplied from a close chamber
beneath, where the upper stratum of coal Śī
shall be constantly undergoing the process of s
coking, the gas from which becomes ignited 32 ||f||
in passing through the open part of the grate §
above, and by causing the said chamber to
descend at pleasure, so as to extinguish the
fire. The figure represents a vertical section
of a register stove, presenting an end or side
view; a is one of the front pilasters; b the en-
tablature; c the back; d the chimney, the
entrance to which is shown by the curved
arrow ; e the top plate, turning upon hinge
joints, to be raised up whenever required for
sweeping; this top does not fill up the space
accurately, but leaves a narrow opening at f,
for the escape of the vapour and dust that may
arise prior to the current being established in
the direction of the arrow, by the effects of the combustion; g are the front grate
s
i
#
#.
º~~~~- -
§
i






FIRE-PLACES. 531
bars; h the receptacle of the coals, including i, the place (as usual) where they
are burned. As the air which finds its way into the close box h, is only sufficient
to coke the coals, their perfect combustion is not effected until they are raised
above the front plate k, at which place the air pours in on all four sides, between
the bars in front, through the side grates, one of which is shown at l, and from
an aperture at 0, under the bottom edge of the back; p is a vertical groove, in
which the bar q (seen end ways) traverses up and down, supporting the movable
bottom plate of the coal box h. To each end of this bar, exteriorly, is attached
a chain r, which thereby suspends the coal chamber (or movable bottom), by
an horizontal rollers, extending across the stove. This roller is the shaft or
axis of a cog-wheel t, and is put in motion by a pinion u ; the axis of u is a
small square pin, fitting into the cavity of the winch v ; the turning round of
the latter winds the chain upon the roller, and elevates the movable bottom q,
which raises the coals, as they may be required for combustion, to supply the
place of those which have been consumed. On turning the winch the contrary
way, the bottom of the coal receptacle descends by its own gravity, and that of
the coals resting on it, as far as the plate ar, when the fire dies away for want
of air. The patentee employs a pall and ratchet to stop the action of the
roller, which is operated upon by pressing upon a pin, placed externally. Two
objections have been urged against these stoves; one, that the current of air
passing through it makes an unpleasant roaring noise, like that of an air
furnace; the other, that the expansion of the coals in undergoing the process
of coking prior to being raised into the open part of the fire, causes them to
adhere so fast to the sides, as to render the friction excessive, and the labour
great, of raising up and getting down the coals. These objections are, how-
ever, we believe, not of an insuperable character, and may be overcome by
mechanical skill.
Mrs. Smith's Stove.—A plan of a stove designed for burning its own smoke,
was communicated by Mrs. Rachel Smith to a periodical journal, which seems
susceptible, by its simplicity of construction and soundness of principle, to be
made effective for the object intended The stove is made exteriorly of the
usual form, excepting that the fire part f is of greater length or height than is
tº sº tº sº º sº * * * * * * * * * * *
g
*
common, and the spaces under the hobs are made into reservoirs to receive the
coals, as shown at c c, for supplying the fire. The hobs are upon hinges, and
form lids, which shut down very closely,–if air tight, the better. The cheeks
of the grate are open at the bottom, so that the coals lying, upon the inclined
planes of the reservoirs descend by their own weight, and occupy the lower
part of the grate; and as the fuel is consumed, or raised by the poker, a fresh
portion of coals enters from either or both of the reservoirs, and fills up the
space. In this manner the fuel is constantly supplied, occasioning little or no
smoke. The reservoirs should be of a capacity sufficient to hold enough coals
for the day's consumption.

532 FIRE-PLACES.
Atkins's Patent Stove.—Messrs. Atkins and Marriott had a joint patent for a
smoke-consuming stove on the principle of the last described, which they
manufactured in a style of great elegance, and adapted to the various situations
and applications of domestic stoves. The patentees state their objects to be,
first, to afford a remedy for smoky chimneys; and secondly, to economize fuel,
and regulate the heat evolved from stoves or grates for warming apartments,
and for the various operations of cooking. In order to effect the combustion
of the smoke, the coals are thrown into a coal chamber at the back of the
grate, which is closed by a door. At the lower part of this chamber there is
an opening through the back into the grate, the interior of the box being formed
so as to throw the coals forward to supply the grate when necessary. The other
improvement maade by the patentees consists of an appendage, in lieu of a
fender, attached to the front and lower part of any kind of stove or grate, which
they denominate a basement. This basement they usually make of a convenient
inclination, to put the feet upon, but it may be made of any figure or dimensions
according to individual taste. It is provided with a drawer or box to receive
the ashes, beneath the fire, and with apertures in front to admit air beneath the
fire bars. The whole of the interior of this basement, except the ash box, is
filled with a mixture of pulverized charcoal and lime; the stove has also a
canopy or cornice filled with similar slow conductors of heat; also each side of
the grate, as well as a part of the back, are provided in like manner. The effect
of these appendages, in retaining that portion of heat which is nearly all lost
to the apartment in other stoves, is doubtless very great; we are, indeed, credibly
informed that it will preserve nearly the same temperature in a room for several
hours after the fire is extinguished. These stoves have pipes or passages for
allowing a column of air to ascend through the basement and upper portion,
which becomes warmed in its passage, and flows out into the apartment above.
Jacomb's Patent Grates.—The principle of this invention also consists in
placing the fresh fuel underneath the ignited portion; but the mode of carrying
it into effect is peculiar. The stove is a kind of grated cage, cylindrical or
parallelopipedal, turning upon axes, which are mounted on side standards.
On two of the opposite sides of the said cage is a grated door, each of them
serving alternately for admitting the fresh fuel, and as an ash grate. The coals
are supplied at the top of the fire ; the door of admission is then shut, and the
grate turned half round, so as to bring the fresh fuel underneath, by which
means the gas emitted becomes inflamed in its ascent through the ignited fuel
above. . The selection of the materials, and the diversification of designs and
proportions for the construction of stoves, will of course depend upon the uses
to which they are applied; but we will select, as an example, the following one
adapted for a parlour. Fig. 1 is a front view, and Fig. 2 is a side view. a a
2
__
º
!
fºLITIſ)*
... III
#: § §:
ºl.1: # # #:
- P º: Fº ºf .
==ºf;=###=#=#=#
º ; # º f #:
Eää.E. =#Eji=#Eft
#
---
.
º º sºrºrº|#2%
22
Łºś:
- tºº:#2 º
| #º
&
ſ {ij
(i.
rº | |
Allllllllll: |||ſ||
-
º
º
-*.
ſº
:
#
-h
º
-
-
£º-º-º-------—----------------
--~~----------------------------
:
º**
%
are the axes, which rest and slide in horizontal grooves b. The two doors
before mentioned, represented in Fig. 5, are made fast by catches e.g. The
stove is put into action by lighting a fire in the ordinary manner with coal or










FIRE-PLACES. 533
other fuel, as near as possible at the top, preferring to place uppermost the
cinders, and green coal undermost; the fire will then gradually find its way to
the bottom, burning with little or no smoke, which, together with the gas or
vapour, is consumed as emitted. When fresh fuel is required, it is to be placed
on the top of the ignited fuel, and the door shut down and secured by the catch
w; the grate is then to be drawn forward in the groove b, and turned round
one half of a revolution on its axis, and then be returned back again to its
former position in the groove. :
Lloyd's Patent Stove consists in the adaptation of a box in a recess at the
back of an ordinary register or other stove, for the reception of sufficient coals
for a day's consumption, which are to be drawn forward into the fire as they
may be wanted, and thus supersede the use of the coal scuttle,_an utensil
which has certainly its inconveniences. That this operation may be performed
with facility, the box at the back of the stove is closed with a sliding door, the
weight of which is supported by a counterbalance suspended over a pulley; it
is therefore drawn up or let down with ease, by means of a small handle placed
conveniently, when the coals may be raked on to the fire by means of the
poker.
Smoke-consuming Stove.—The annexed cut is
illustrative of a design, by an anonymous inventor,
for a stove to consume its own smoke. We are not
aware of its having ever been constructed, but as it
presents a novel and elegant arrangement of parts,
calculated to answer the intended purpose in judi-
cious hands, we give it insertion. The inventor
proposes that the smoke from the fresh fuel shall
be allowed to ascend up a short flue, and then
descend and rise again through a tube placed in
the middle of the fire, after which the tube conducts
the remaining incombustible gases into the chimney.
The intense heat of the tube which rises through
the fire must necessarily burn the smoke, economize
fuel, and increase the temperature of the room.
Silvester's Patent Stove.—The common methods
of heating buildings by means of hot air stoves had
been much and justly complained of, from the salubrity of the air being fre-
quently injured by its coming in contact with the surface of a stove compara-
tively small, but intensely heated; and to remedy this evil, the late Mr. Silvester
introduced cockle stoves, first in the Infirmary of Derby, and afterwards in
many other places, with large heating surfaces, that they might be sufficient to
heat moderately a large quantity of air, but not to be heated so high as to
injure any portion of it; and thus was obtained an extensive ventilation by
air moderately warmed. (See AIR.) Still, however, stoves of this kind,
without considerable care and skill on the part of the firemen, were liable to
become over-heated, and at times to deteriorate the air; and to obviate the
possibility of this defect seems to be a principal object with the present
patentee. He proposes, in the first place, to lower the fire grate, till the bottom
bars are on a level with the surface of the floor of the room in which it is
placed. The fire bars are prolonged and widened to touch each other in front
of the fire, so as to form a hearth. They require no fastening into their places,
but simply to be laid upon appropriate bearings at each end. There are grooves
made on the under sides of the fire bars, for the admission of fresh air for
supporting the combustion of the fuel within the grate, and for the escape of
hot air into the room. It is stated that the bars may be either made of equal
lengths, to constitute a rectilineal hearth, or of different lengths, to constitute a
curvilineal one, at pleasure. When the ash pit, which is situated below the
fire in the usual manner, requires clearing out, a few of the fire bars are to be
removed, which can be effected with facility, as they are not made fast to any
thing. Mr. Silvester proposes, in the second place, to surround at least three
sides of his fire with a vessel containing water, and upon the exterior of this
*2 .
t? Y

534 FIRE-PLACES.
water vessel he causes a large quantity of cold air to impinge, that its tem-
perature may be elevated sufficiently to communicate the required degree of
heat or ventilation to any adjacent apartments to which it may be conveyed.
For the purpose of conveying the cold air to, and the heated air from, the
water vessel, the patentee proposes to employ apparatus of the same description
as that employed with the hot air cockles invented by his father.
Gaunt and Eckstein's Grate.—The stove designed by these gentlemen (for
which they had a patent in 1831,) has a grate of bars, of a semi-elliptical form,
attached to a straight back, which is brought much further forward than are
the backs of stoves of the usual construction, by which arrangement three
sides, or what is equivalent to three sides, of the fire, is in a situation to radiate
heat into the room. Immediately over the fire is placed a metallic hood, which
receives and radiates into the room a portion of the heat which would otherwise
pass up the chimney. The distance between the fire and hood is diminished
and increased at pleasure, by elevating or depressing the grate containing the
fire, and thus is obtained the means of increasing or diminishing at pleasure
the draft of the fire, and of preventing the escape of smoke into the room.
The change in the altitude of the grate is effected by means of projections
from the grate passing through vertical slits in the back, which projections are
joined together by a cross bar, attached to a lever by a connecting link; this
lever has on its exterior end a toothed sector, which is actuated by a small
pinion, whose axis receives a regulating winch, passing through a small hole in
the back. This hole, with the pinion axis, is the only part connected with the
rising apparatus which is visible in front, which admits of their being manu-
factured in a style of great elegance and neatness.
Maw's Stove.—This apparatus, for which Lieut. Maw obtained a patent in
1831, consists in the introduction of a fuel drawer, or receptacle for the fuel,
which is placed under a grate of the usual construction, in order that the most
volatile portion of the fuel may be liberated and be consumed in its ascent through
the fire; and when the coal has thus, by parting with its gaseous matter, been
converted into coke, it is to be removed from the fuel receptacle, and placed
upon the fire, leaving the receptacle at liberty for the introduction of another
supply of fresh fuel. A front elevation of one of Lieut. Maw's fire grates is
Fig. 1. Fig. 2,
|
(4/
A
H
exhibited in the above cut at Fig. 1, and a sectional side view, Fig. 2, wherein
a shows a grate of the usual construction, and b a fuel drawer or receptacle,
having a grating underneath, for the admission of atmospheric air to maintain
the combustion. The openings in the grating between the fire and the fuel
receptacle are made at some distance from the front, that the volatile matter,
in its ascent, may not pass so near the front of the fire as to be cooled, lest it
escape without being consumed. The advantages which would result from
having the fuel supplied to a fire under the ignited portion, have been long
acknowledged; and of the various plans that have been proposed, we do not
think there is one so well calculated to answer the purpose of burning the
smoke as that of Lieut. Maw.
Witty's Fire Places. – Mr. Witty, by a judicious attention to proportions,

FIRE-PLACES. 535
and the conveniences required, has succeeded in adapting the original invention
of Watt (described under the word FuRNAce,) to domestic stoves, particularly
those of the close kind. Mr. Witty has, however, unadvisedly taken out a
patent for these stoves, although we can discover nothing that is original in the
principle nor in the arrangement of the parts. Some elegant and very effective
stoves on this plan may be seen at the Museum of National Manufactures and
the Mechanic Arts, in Leicester-square.
Nott's Patent Furnaces.—A very effective kind of close stove, particularly
adapted to large rooms, halls, and churches, and possessing considerable
novelty of appearance, has lately been introduced into this country by
Mr. J. B. Nott, from the United States. In the upper part of a low pedestal
is a large capacious chamber, capable of holding a sufficient supply of coals for
the day's consumption; from this receptacle the coals gradually sink down, as
they are consumed, in front of the grate, and are deposited upon an arched
grating, supported upon a pivot, upon which it is made to oscillate, (by using
the poker as a lever for that purpose,) and thereby clear the bars of ashes; and
when it may be necessary to clear or put out the fire entirely, the said vibrating
grating is moved through a greater angle, by which all the ignited fuel thereon
is thrown out at either end of the arch. To give the lively appearance of an
open fire, and the security of a close stove, the front of the stove is enclosed by
windows of talc, through which the glowing fuel is seen. The air is admitted
for lighting the fire by leaving the ash-pit drawer a little way open, and when
ignition is complete, the drawer may be entirely shut, as sufficient air finds its
way through the imperfect junctions or fittings of the metal, to preserve a vivid
combustion of the fuel. The fire chamber is encased in fire brick, or some
other suitable slow conductor, which prevents the surrounding cast iron from
obtaining that high temperature which is found to deteriorate the air of the
apartment, and the heat is in consequence more uniformly diffused over the
other parts of the structure, which presents altogether a very extensive surface
of metal for the radiation of heat, principally derived from a tall ornamented
chimney, of a flat pyramidal or pilaster-like form. In this chimney there is a
turn valve, to regulate the egress of air, the action of which, together with the
management of the ingress crevice at the ash-pit drawer, determines the
quantity of heat or the rate of combustion of the fuel. In fitting a stove of
this kind to a room having the ordinary cavity for the fire-place, Mr. Nott
converts the latter into a hot air chamber, and places his close stove upon the
hearth in front. A stove of this kind is employed for warming the extensive
range of rooms at the Museum of National Manufactures and the Mechanic
Arts, in Leicester-square, which it does most efficiently, with very great economy
of fuel. Anthracite, or stone coal, which is almost wholly free from bituminous
matter, and emits, in consequence, scarcely any smoke, may be very advan-
tageously burned in stoves of this kind.
German, Pyramidal, Pedestal, Sarcophagus, &c. Stoves.—All grates of this
class are, strictly speaking, close stoves, the fire being entirely shut up within
them, the flue or chimney usually consisting of a metallic pipe, which is con-
ducted through the walls of the room to the external atmosphere. The German
stove is a vertical cylinder of sheet iron, mounted upon legs, having internally,
and about midway, a short cylinder of cast iron, with a grating at bottom,
which constitutes the fire room, and underneath is the ash pit. The tops,
which are variously formed to suit particular purposes, are made to take on and
off, so as to allow of baths, boilers, or retorts, to fill up the aperture, and thus
become the cover to the upper part of the furnace; the application of heat is
thus very convenient and effective, and is much used for chemical processes,
and manufacturing operations on the small scale. The pyramidal, pedestal, and
sarcophagus stoves are of similar internal, construction to the German or
cylinder stoves, but they are usually of cast iron, and designed with a view to
ornament as well as utility: their external forms are explained by their names.
Having now described the principal varieties of stoye grates or fire-places in
their most improved forms, (including air stoves, which will be found under the
article AIR), we shall close this part of the subject by a few observations on the
536 s FIRE-PLACES.
proper construction of fire-places in general, in order that the reader may
understand the defects that may exist in his own, and know how to apply the
remedy. In open fires the bars should not be larger than is necessary for
strength, as they obstruct the radiation of heat, and prevent the egress of air,
which is requisite for making the fire burn clear. To attain a clear fire,
Mr. Tredgold justly says, that the sides of the burning fuel should be at least half
surrounded with slow conductors of heat, otherwise the heat developed will pass
off so quickly by conduction, that the fuel will burn dead, and that heat which
ought to be radiated will be expended in warming the walls, &c. behind the
fire. Iron is a very rapid conductor of heat, and therefore it should be used
as sparingly as possible. Fire brick, a slow conductor, is employed with much
advantage for the backs and ends of grates by a few manufacturers, but iron-
mongers in general seem to think it more desirable to use iron than to economize
fuel, or to work on sound principles. But when a fire-place, made of slow
conducting materials, is large and filled with fuel, as soon as the fire becomes
bright the heat is extremely intense and scorching; when the fire is in this
state it is often too powerful for the room, though perhaps barely sufficient
when the combustion is less perfect. This may be remedied by any method
which enables us to expose a greater surface of hot matter with the same bulk
of fuel, and at a lower degree of heat. Some time ago “fire balls,” (spheres
made of baked clay,) were used with this object; but their inconvenience, when
not judiciously attended to, brought them into disrepute. An improved
substitute for them has been suggested by Mr. Tredgold, when the fire is
of greater length than 18 inches; that of building a projection from the back
of the grate (and of the same depth) to within three inches of the front bars.
This projection should be of good fire brick, and built firmly in with the other
part of the back. Thus is left a space for a sufficient body of fire on each side,
and the surface is increased without adding to the mass of burning fuel.
The combustion of the fuel in an open grate should not be faster than is
necessary to produce a clear fire. To guard against the loss of heat by the
warm air of the room ascending the chimney, two partial remedies have been
adopted—that of lowering the mantel, and contracting the throat of the
chimney; but the first of these remedies impairs the ventilation of the room,
and the second, causing a rapid draught, increases the consumption of fuel.
For some rules in duly proportioning the flues, see the article CHIMNEY. A
grate should offer as little obstruction as possible to the radiation of heat, and
therefore the usual mass of metal below the front bars, called a fret, is objec-
tionable; and the sectional form of bars should be that of a wedge, with the
sharp extremity rounded off, which part should be inside, or next to the fuel,
as it is advantageous to have as little metal as possible in contact with the fuel.
There is, however, no objection to the employment of metallic covings, as
reflectors of heat, when separated by a slow conductor from the metal of the
grate; and instead of these being blackened, as they are usually in the common
Rumford stoves, they should be bright or polished surfaces, and preferably of
brass to the other common metals. The angle best suited for the covings is
459 with the front line of the grate. The height of the grate from the floor is an
object of some importance; if it be placed too low, the heat is expended almost
wholly on the hearth, and the fire-place seems buried within the fender; if it
be placed too high, a person's face is scorched, while too small a portion of
heat is given to the floor to render a room comfortable; but a high mantel has
the advantage of producing a more effectual ventilation. Mr. Tredgold con-
sidered that the top bar of stoves ought not to be less than 20 inches from the
floor, and never exceed 2 feet; and when the lower part of the fire is not
buried in a mass of metal work, there will be an abundant supply of heat
thrown upon the floor from the greater height. The space between the top bar
and the mantel will require to be proportioned to the size of the room and the
height of the chimney, and in ordinary cases may be about 15 or 16, inches.
With respect to the proportion of grates to different sized rooms, Mr. Tredgold
has, from observation, deduced the following rule –Let the length of the front
of the grate be made one inch for each foot in length of the room, and the
FIRE-PLACES. 537
depth of the front be half an inch for each foot in breadth of the room. If the
length of the room be such as requires the grate to be longer than 24 feet,
two fire-places will be necessary; and in that case the same proportions may
be adopted, divided into two grates, unless the room be very wide, when a
greater length should be given, and less depth, so as to preserve an equivalent
area. For various information connected with this subject, see the articles
VENTILATION, CoMBUSTION, AIR, FURNAcEs, &c.
Welles's Patent Peripurist.—This is a small portable cooking stove, and is
very ingeniously contrived. The patentee states in his prospectus of it, that
“it boils water, prepares coffee and chocolate in a very superior manner, boils
eggs, cooks a beef-steak or a slice of ham, all in less than ten minutes. For
dinner, it will prepare soup, steam vegetables, and cook fish, chops, or steaks,
at the same time; and for these one farthing's worth of fuel is sufficient.”
Fig. 1 is an external view, and Fig. 2 is a vertical section; a is a small cone of
cast iron, having at the bottom a grating, on which is put the fuel (charcoal),
broken into small pieces; below this is a small chamber b, perforated at its
sides for the admission of air, and containing a small pan to receive the ashes,
and also to light the charcoal by a piece of paper; the vessel c contains water,
which entirely surrounds the cone; the next vessel e above is intended to be
Fig. 1. Q
º
ſ
º I
P.
|
-s º
º
º
|
tº Hº
ill LIHTiiſillº
º E iſ º
riſiſ ſiliº
* † = º *:::===
| −iſi;|
Tº *E=#||||Wº:
sº 'minº
{ijñigº ; iiii ºii.
ased as a steamer; it has in its centre a frustrum of a cone, the lower edges of
which descend below the bottom of the vessels, and fit upon the cone beneath,
so as to carry up the flue to the chamber above, which has open perforated
sides, whence the vapours produced by the combustion escape. On the top of
the cone there is a valve for enlarging or diminishing the aperture, having a
horizontal rod fixed to it, which passes to the outside of the vessel, as shown.
The vessel over this, f, is, we suppose, a stew-pan, or something of the kind;
it is heated by the hot air and direct influence of the fire; above this pan is
placed in a cavity of the cover a small pot for warming small quantities of
liquid. There are several appendages or vessels for peculiar purposes, such as
the boiling of eggs, &c. which fit one over another in a similar manner to
those described. The apparatus is proposed to be used on the breakfast or
dining-table, to be taken in a carriage, in a boat, or carried by pedestrians.
Tozer's Patent Calefactor. — This is another ingeniously contrived little
cooking stove, and is intended to meet many of the wants of a small family,
especially in the summer season, when the smallest quantity of artificial heat is
desirable. The diagram in the next page is explanatory of its construction
and arrangement when applied to roasting and steaming ; some of the parts
in the drawing are slightly varied from their real positions, for the purpose of
elucidation by a single figure. a is the steam boiler, which has a large ellip-
tical opening down the centre for depositing a variety of culinary vessels













538 FIRE-PLACES.
therein; b an aperture for charging the boiler with water; c a stop-cock for
drawing off the water as may be required, but placed high in the boiler to
admit a draught of air to the grating e, on which the charcoal is burned 3–the
grating is, strictly speaking, a strong iron plate, perforated all over for the free
admission of air through the holes; j is termed the oven pan, which is a cast-
iron dish, suspended about half way down the elliptical opening; g a sheet-iron
cover; h a pipe conveying the steam from the boiler a to the steamers i and j,
which separate in the middle, and allow of one or both being used at a time;
each of these steamers may be subdivided into distinct compartments; k, a
sliding damper for enlarging or contracting the air passage d, so as to increase
or diminish the combustion of the fuel, as may best suit the peculiar culinary
process. When the apparatus is not required for roasting, but for boiling, or
making soup or broth, the oven pan is to be removed, and in its place the
required vessels (all of which are made to fit) are deposited. In some cases
the patentee adopts two half-kettles instead of one. A current of heated air
is constantly kept up, entering at the grating at bottom, and passing out at the
grating above, where the heat is reverberated against the top and sides of the
cover, prior to its escape through a small central aperture in the latter.
FIRE-SHIP. A small vessel filled with combustible matter, and employed
for the destruction of an enemy's shipping by being run into the midst of them,
and set on fire by the crew before they quit the vessel.
FIRE-STONE. A coarse kind of free-stone, obtained at Reigate and other
places, which is capable of bearing a considerable degree of heat, and is there-
fore used in the construction of furnaces, ovens, &c. Its colour is a pale grey,
tinged with green, which the fire changes to a light red.
FIRE-WORKS. As the leading object of this work is utility and not mere
amusement, we shall but very briefly notice the nature and composition of
artificial fire-works. Of these the most generally interesting, from the great
altitude of their flight, are rockets. They are made by ramming into strong
cylindrical paper cases (put into wooden moulds to support them) powdered
gunpowder, or the ingredients of which it is composed; namely, saltpetre, sul-
phur, and charcoal, very dry. To represent a fiery rain falling from the rocket,
mix among your charge a composition of powdered glass, filings of iron, and
sawdust; this shower is called the peacock's tail, on account of the various
colours exhibited. Camphor mixed with the charge produces white or pale
fire; resin, a reddish colour; sulphur, a blue; sal ammoniac, a green; anti-
mony, a reddish yellow; ivory shavings, a silvery white; pitch, a deep or dark
coloured fire; and steel filings, beautiful corruscations and sparks. Sticks are
fastened to the rockets for the convenience of discharging them, and causing
them to pass through the air like an arrow; the resistance of the air to the
rush of fire at the end of the rocket causing it to ascend. Artificial fire-works
differ from each other very much in point of simplicity of construction. Some
require very little dexterity in the preparation, and are either employed as

FLAX DRESSING. 539
appendages to works of greater importance, or, if used by themselves, are con-
fined to the sports of school-boys. Of this nature are squibs, crackers, ser-
pents, stars, sparks, maroons, saucissons, pin-wheels, leaders, Roman candles,
&c. Others are very complex in their structure, require considerable address
and ingenuity, and form the amusement of fashionable circles on occasions of
public rejoicing, or private festivity: such are wheels, suns, globes, pyramids,
&c., and rockets of various kinds. Those who wish for precise instructions in
the preparation of these resplendent trifles, we would recommend to consult
the article PyRotechNY, in the Oaford Encyclopedia.
FLAGEOLET. A little flute, made of box or other hard wood, with an
ivory mouth-piece, and having six holes besides the one at bottom, and one
behind the neck. Great improvements were made in this pleasing instrument
by the late Mr. Bainbridge, who also invented the double flageolet, upon which
one person may play duets.
FLAIL. An instrument for threshing corn. It is composed of two staffs
united at one end of each by strong double leathers.
FLAME. The luminous phenomenon produced by the combustion of
gaseous substances, or under certain circumstances of a solid and a gaseous
body.
FLANNEL. A kind of loose woollen stuff, composed of a woof and warp,
woven in a loom with two treddles, in the manner of baize.
FLAX. A plant having a slender, round, hollow stalk, about two feet high;
its bark is full of filaments, like hemp; the leaves are long, narrow, and
pointed; it bears a blue flower, to which succeeds a roundish fruit, about the
size of a pea, containing ten little seeds, full of an oily substance, or meal. There
are twenty-five species, of which the most remarkable are the common annual
flax, and the perennial Siberian flax.
FLAX DRESSING. Before flax can be converted into cloth or other
articles, it undergoes certain preparatory processes, constituting what is called
“dressing;” the object of which is to separate the boon, or core, from the flax,
which is the cuticle, or bark of the plant, and to straighten out the fibres for
the spinner. These operations are sometimes performed by hand, but at the
present day more commonly by machinery, driven by steam or water power.
When the flax is dressed by hand, the bark is separated from the core by
means of an instrument called a “flax-brake,” composed of three wooden teeth
or swords, fastened longitudinally on a horizontal bench, and of a lever, to the
under side of which are fixed similar, but rather smaller teeth, which fit in
between the interstices of the others. The flax being held in the left hand
across the under swords of the brake, the upper teeth are then with the right
hand quickly and often forced down upon the flax, which is artfully shifted and
turned with the left hand, in order that it may be fully and completely broken
in its whole length. The fibres are then straightened by means of a kind of
comb called a “hackle,” whence the operation is termed “hackling.” The
hackle is composed of a number of long teeth or spikes, fixed firmly in a bench;
and the workman striking the flax upon the teeth, draws it quickly through
them. To persons unacquainted with this kind of work it may seem a very
simple kind of operation; but, in fact, it requires as much practice to hackle
well as any other operation in the whole manufacture of linen. The workmen
use finer, or coarser, and wider-teethed hackles, according to the quality of the
flax; generally putting the flax through two hackles, a coarser one at first, and
then a finer one in finishing it. But the hand methods of breaking and
scotching of flax are, however, too tedious in their operation to give satisfaction
to the manufacturers in the present advanced state of mechanical science, and
accordingly mills have been constructed by which these preparatory operations
are much facilitated. These mills differ greatly in their form, and the mode
of their operation. A very simple and efficient one is described in Gray's
Eaperienced Millwright, and is constructed as follows:—Upon the main shaft,
or axis of a water-wheel, is fixed a large bevilled wheel, which turns three
horizontal fluted or toothed rollers, by means of a pinion on the axis of the
middle one, the upper and lower rollers being kept pressed against the lower
540 FLOATING BODIES.
one by weighted levers, and being carried round by contact with it. The
driving-wheel likewise gives motion to an upright shaft, by means of a small
pinion fixed upon the foot of the shaft; upon the upper part of this shaft are
fixed cross arms, to which are attached scotches, revolving within a cylindrical
casing. The rough flax is made up into small parcels, which being introduced
between the middle and upper rollers, pass round the middle one, and this,
either having rollers placed on its off side, or being enclosed by a curved board,
turns the flax out between the middle and under rollers, when the flax is again
put in between the middle and upper one, and passes round the same course until
it be sufficiently broken or softened, and prepared for the scotching machine. The
scotches, as before stated, are inclosed in a cylindrical casing; in the periphery
of this casing are a number of apertures, and at these holes a handful of flax
being held, the revolving scotches clear off the refuse. -
FLEAM. An instrument containing several lancets, jointed so as to shut
up into a handle in the manner of pocket clasp-knives.
FLINT. A mineral consisting of 98 silica, 0.50 lime, 0.25 alumina, 0.25
oxide of iron, 1 loss. The domestic use of this stone, for producing light by
collision against steel, is well known. It is also much used in gun-locks for firing
the powder. The manufacture of gun-flints employs numerous hands in this
country; as independently of the large quantity required for home use, consi-
derable shipments of them are made to various parts of the world, where the
mineral is not supplied by nature. The manufacture of gun-flints was for a
long time kept secret; and we are indebted to M. Dolimien for the first pub-
lished account of the method practised in France, which he has given in the
Memoire de l’Institute National de Sciences. The masses of flint which are best
fitted for this purpose, are of a convex surface, approaching to globular. The
best flint nodules are generally from two to twenty pounds' weight ; the
colour should be uniform in the same nodule; their transparency should be
sufficient to admit letters to be distinguished through a piece of the stone of a
quarter of a line thick, laid close upon the paper. Their fracture should be
perfectly smooth and equal throughout, and the fragments slightly conoidal.
The last of these properties is the most essential, since on it depends the facility
with which the nodule is divided into gun-flints. All flints that prove deficient
in any one of the above characters, either naturally or by a long exposure to
the air, are called intractible, and rejected by the workmen. There are several
hammers and a chisel employed in the operation of fashioning the flints, by
which means it is said that a clever workman is able to manufacture a thousand
flints in the space of three days. Gun-flints are also manufactured at Purfleet
in Kent, and in various other parts of England, in a very superior style.
FLOAT BOARDS. Those boards which are fixed to the rim or circum-
ference of undershot water-wheels, serving to receive the impulse of the stream,
by which the mill is put in motion.
FLOATING BODIES, are those bodies which swim on the surface of a fluid,
the stability, equilibrium and other circumstances of which form an interesting
subject of mechanical and hydrostatical investigation, particularly as applied to
the construction and management of ships and other vessels; but as the sub-
ject is one involving the higher branches of calculation, and as it is difficult to
obtain practical results which shall accord with those obtained from theory, on
account of the difficulty of estimating the amount of the disturbing forces, our
remarks must be brief and general.
The equilibrium of floating bodies is of two kinds; viz. stable or absolute,
and unstable or tottering. . In the one case, if the equilibrium be deranged,
the body merely oscillates about its primitive position, to which it finally returns,
and this is called firm or stable equilibrium; but in the other state of equili-
brium, if the system be ever so little deranged, all bodies deviate more and
more, and the system finally oversets and assumes a new position; and this is
called unstable or tottering equilibrium. The stability of a floating body is
greater as its centre of gravity is lower than that of the displaced fluid; it is
for this reason that the ballast is put in the lower part of vessels to prevent their
oversetting. The nature of the equilibrium as to stability, depends on the
FLOORING CRAMP. 541
position of a certain point, called the meta-centre, or centre of pressure.
When the meta-centre is lower than the centre of gravity, the equilibrium is
tottering; when the meta-centre coincides with the centre of gravity, the body
will remain at rest in any position it is placed in ; when the meta-centre is
above the centre of gravity, the body will always have a tendency to recover
its original position, and the equilibrium will be stable.
FLOORING CRAMP. A machine invented by Mr. Andrew Smith, for
laying down floors, so as to make very tight and close joints with great facility.
The annexed engraving shows a perspective view of the machine as in opera-
tion, by which its construction and the mode of using it are both made
apparent. a is a lever of the second class, about 2 feet 6 inches long, with a
handle at the upper end, and forked at the lower, so as to be attached to two of
the opposite sides of a block of cast iron b, by bolts at c. The block b is about
6 inches square, and 3 deep, with a large groove capable of being increased or
diminished in its depth for the reception of joists of different sizes. For this
purpose, it has on one side a shifting loose cleat or plate e; kept in its place by
stout pins; and on the other end, on the other side of the joist, there is another
groove d, which contains two pieces of metal, with wedge-formed surfaces;
between these the long driving wedge f is forced by a slight blow with a ham-
mer, which compresses the joist between the metallic surfaces, which are jagged
or armed with short projecting teeth, that fix themselves into the wood, and
gripe it very fast; g is a movable piece of cast iron, made to press against the
edge of the flooring board, with its broadest side; the two other sides or parts
of this piece are stout square bars, at right angles with the other, which are
inserted a part of their breadth in shallow grooves, one on each side of the
tj Z

4 x
542 FLOORING MACHINE.
block b, and serve to guide the former in its action. It will be observed that the
two forks of the lever a pass through the side bars of g, which therefore gives it
motion. To use this machine, it is put upon the joist, and pushed up to the
board laid down; a slight blow upon the wedge f fixes it firmly to its place;
the handle of the lever is then pulled by the workman towards the boards,
causing the sliding piece g to press the edges of the boards together with as
much force as to render their junction imperceptible; the stay h is jointed
loosely to the back of the lever a, and following the motion of the lever, the
jagged end of its lower extremity sticks into the joist, holds the lever in the
position it was drawn, and preserves the pressure against the board, while it is
nailed down by the workman. To remove the cramp, all that is necessary is
to strike the wedge on the opposite side, which loosens the whole, when it is
drawn back to take the next board, which is operated upon in a similar manner.
FLOORING MACHINE. A machine invented by Mr. Muir, of Glasgow,
the object of which is the preparation of complete flooring boards with extra-
ordinary dispatch, and in the most perfect manner; the several operations of saw-
ing, planing, grooving and tongueing, being all carried on at the same instant,
by a series of saws, planes, and revolving chisels.
The figure in the next page represents a plan of the machine, slightly modified,
to render the construction more easily understood by the reader. The machinery
is adapted for the simple planing of boards, as well as the preparation of square
jointed or plain jointed flooring. We shall commence our description by an
account of those parts which constitute a simple planing machine, and then
proceed to describe the apparatus by which it is adapted to the preparation of
jointed flooring. The planing machine consists of a perfectly flat and straight
bench, d d d, which should be at least twice as long as any board intended to be
prepared upon it. This bench is made fast to a block of stone c e or other
solid matter, which, together with a suitable framing, serves to keep the whole
machinery as firm and steady as possible. Along one side of this bench is a
raised guide e e, which extends as far as the circular saws i i, but only a part
of it is shown in the figure, in order to bring some of the other arrangements
more into view. About the middle of the bench a metallic plate a a is let in
flush with its surface, which forms a durable stock for the plane irons; these
plane irons are of the usual form, but of greater breadth than the boards to be
planed. The projection of their cutting edge is effected and regulated by screws,
and the number of plane irons employed at a time is determined by the degree
of finish required for the surface of the boards; three plane irons are however
generally used, as shown at h h h, the dark spaces being the mouths of the
planes: from this it will be seen that it is the lower side of the board that is
planed, and the shavings are delivered under the machine. An endless pitched
chain, having catch hooks at convenient distances, takes hold of the boards as
they are put into the machine in succession, and drags them along the bench ;
the edge of one of the sides of each board passing under a rebate in the guide
or fence (as shown in the figure) prevents the board from bending upwards by
the action of the chain, while it is pressed down to the plane irons by springs
or weighted levers, as seen at b b, which are mounted upon antifriction rollers,
the axles of which are so inclined as to cause the boards to be uniformly
driven against the fence, and to pass in a straight line through the machine.
Motion is given by a band from a large revolving drum, placed above the
machine, (not shown in the figure,) which communicates with the drum u, upon
the shaft of which is a pinion, that drives the toothed wheel j : the axis of
the latter carries the pitched rigger t, round which the endless chain is passed,
and stretched in a parallel direction with the bench, by passing over the pulley
2, at the opposite end of the machine; at this place only a small piece of the
chain is brought into view, as the introduction of the whole of it would hide or
tend to confuse some of the other parts of the apparatus. The pulley z is
mounted upon a tightening frame, y, which moves upon a joint at the lower
end, the tension being increased or lessened by the wedges 11, or by regulating
screws. The parts we have thus described constitute a separate machine for the
planing only of boards. For the preparation of plain or square-jointed flooring
FLOORING MACHIINE. 543.
boards, the following additional apparatus is brought into operation. A part of
the fence e is slightly hollowed from the direct line of the bench, to admit of
projecting inequalities in the edges of the boards; these are removed by irons or
cutters fixed on a horizontal revolving plate f. the periphery of which enters
an aperture in the fence e: and it is on the edge of the board presented to this
side of the machine that a tongue or feather is formed when required. To
t
i
t
i
--~~~~
produce this effect two circular saws, g and h, are used, one of which, g, revolves
under the board, and cuts it upward; the other, h, revolves above the board, and
cuts it downwards, to such a depth only on each side as to leave a tongue or
feather of the required thickness uncut. By the progressive motion of the
board it next passes under the operation of two circular saws i, one only of
which can be seen, as the other is directly underneath on the same spindle, and
separated only by a ring or washer, which is of the same thickness as the tongue.
These saws, acting horizontally, or at right angles to those at g and h, cut off the
superfluous wood, and leave the tongue projecting from the board completely




544 FLUORIC ACID."
formed. The opposite edge of the board is cut parallel to the other by a circular
saw k revolving vertically, which is called the “breadthing” saw; a guide fixed to
the head of o, which supports the spindle of this saw (but which cannot be seen
in the figure), is so placed as to conduct the superfluous pieces, separated from
the boards by the saw k, underneath the circular saw l; the slips are thus
removed out of the way of the latter saw and preserved. The saw l revolves
horizontally, and is called the “grooving saw ;” it is considerably thicker than
ordinary circular saws, and has long teeth to admit of their receiving a “set”
to cut out the whole of the required groove at one operation. The spindle
head which carries the grooving saw is adjusted and fixed by screws to a
bracket attached to the head o, the latter being placed in slides, which keep it
steady, and conduct it in a parallel direction when moved to or from the bench.
All the parts that operate on this edge of the board being thus connected,
advance or recede together. This movement is effected by means of a screw
fitted with collars to the fixed puppet 3, and working in a nut in the back part
of the head of the screw is turned by the handle n, and an index on the head
o points out the relative position of the circular saw k with respect to the other
side of the machine, and consequently indicates the various breadths of the
finished boards by pointing to a divided scale of inches and parts fixed upon
the block c. All the saws are fixed on to the spindles in the ordinary way, by
screws, nuts, and washers ; but the spindles are considerably thicker than
usual, to admit of their being fitted with cutters or irons, which, by cutting
horizontally, rebate the superfluous thickness of the board to a sufficient extent,
from that part which is destined to form the under side of the floor in all floor-
ing boards. The heads, which carry the vertical saws gh, are placed on slides
fixed to the block c e c, their horizontal position being adjusted by regulating
screws, worked by the handles p and r, and their spindles elevated or depressed
by proper adjusting screws. Motion is communicated by endless bands from
a large drum wheel above the machine, such bands, embracing all the vertical
saw pulleys, and also the rigger or pulley w of the intermediate shaft v w; and
this intermediate shaft, by means of half crossed or twisted bands 44, gives
motion to the horizontal saws i and l. The circular plate or plane fis also
impelled by another half twisted band 5, from a pulley 6, on the axis of the saw
g, The power which impels the whole machine is derived from a steam
engine or other prime mover applied to the shaft of the large drum wheel
before mentioned. Several of these machines have been for some time past
in constant use; one of which, at Pimlico, we have often witnessed the suc-
cessful operation of.
FLOUR. The fine particles of grain, usually obtained by grinding in a mill.
See FARINA, CoRN, and MILLs.
FLUID. A body whose parts yield to the slightest force when impressed,
and by yielding, are easily moved against each other. Fluids are divided into
elastic and non-elastic. Elastic fluids are those which may be compressed into
an exceeding small compass, but which, on removing the compressing force,
resume their former dimensions; and these are distinguished as airs or gases.
Non-elastic fluids are those which occupy the same bulk under all pressures,
or if compressible, it is only in a very slight degree, as water, oil, &c., and these
are denominated liquids, except in the case of metals in fusion. The physical
nature, laws, and effects, of non-elastic fluids at rest, constitute the science of
Hydrostatics, and when in motion, of the science of Hydraulics, or Hydro-
dynamics; those that relate to elastic fluids appertain to Pneumatics.
FLUOR SPAR. The native fluate of lime.
FLUORIC ACID. The name given to an undecomposed substance, which,
combined with lime, constitutes the fluor spar. Fluoric acid may be obtained
by putting a quantity of the spar in powder into a leaden retort, pouring over
it an equal quantity of sulphuric acid, and then applying a gentle heat; a gas
ensues, which may be received in the usual manner in jars, standing over mer-
cury. This gas is the fluoric acid, which may be obtained, dissolved in water,
by luting to the retort a receiver containing that fluid. The distillation is to
be conducted with a very moderate heat, to allow the gas to condense, and to
< FLUX. 545
prevent the fluor itself from subliming. The properties of this acid are, that,
as a gas, it is invisible and elastic like air; but it will not maintain combustion,
nor can animals breathe it without death. In smell it is pungent, something
similar to muriatic acid. It is heavier than common air, and corrodes the skin.
When water is admitted in contact with this gas, it absorbs it rapidly; and if
the gas be obtained by means of glass vessels, it deposits, at the same time, a
quantity of silica. Water absorbs a large portion of this gas; and in that state
it is usually called fluoric acid by chemists. It is then heavier than water, has
an acid taste, reddens vegetable blues, and has the property of not congealing
till cooled down to 239. The pure acid may be obtained again from the com-
pound by means of heat. Fluoric acid gas does not act upon any of the
metals; but liquid fluoric acid is capable of oxyding iron, zinc, copper, and
arsenic. It does not act upon the precious metals, nor upon platina, mercury,
lead, tin, antimony, cobalt. It combines with alkalies, earths, and metallic
oxides, and, with them, forms salts denominated fluates, of which the true fluor,
Derbyshire spar, or fluate of lime, consists of
Lime . . . . . . . 57
Fluoric acid . . . . . 16
Water . . . . . . . 27
-ms-
100
The most remarkable property is that already alluded to, viz. the facility with
which it corrodes glass and siliceous bodies, especially when hot, and the care
with which it holds silica in solution, even when in a state of gas. This affinity
for silica is so great that the thickest glass vessels can withstand its action only
a short time. With respect to the nature of the substance usually termed
fluoric acid, it has not yet been determined experimentally whether it be really
a compound of some unknown base with either oxygen or hydrogen, or whether
it be a simple substance like chlorine. Dr. Thompson inclines to the opinion
that it is a compound of an unknown radical with hydrogen, and not with
oxygen; but Sir H. Davy made several attempts to separate its hydrogen, but
without success, although he applied the power of the great voltaic batteries of
the Royal Institution to the liquid fluoric acid; neither could he decompose it by
passing it with chlorine through a platina tube heated red hot, nor by distilling
it from salts containing abundance of chlorine or of oxygen. Dr. Ure there-
fore observes, that by the strict rules of chemical logic, fluoric acid ought to be
regarded as a simple body, for we have no evidence of its having ever been
decomposed; and nothing but its analogy with the other acid bodies has given
rise to the assumption of its being a compound.
FLUORINE. The imaginary radical of the above acid.
FLUTE. One of the simplest musical instruments of the wind kind. It is
played with a mouth-piece at the end, and the notes are changed by opening
or stopping the holes ranged along the side. The German flute differs from
the former, the end not being put into the mouth, but closed by a plug, and
the lower lip being applied to a hole about three inches from that end. As
usually constructed, this instrument has six open holes, and a seventh hole
closed by a key, as in hautboys, bassoons, &c.; but numerous improvements
have been made in them, and they are now frequently made with eight or even
ten keys, by which the fingering of many musical passages is much facilitated.
FLUX. A general term used to denote any substance or mixture added to
assist the fusion of minerals. In the large way, limestone and fusible spar are
used as fluxes. The fluxes made use of in philosophical experiments consist
usually of alkalies, which render earthy mixtures fusible by converting them
into glass, or else glass itself into powder. Alkaline fluxes are either the crude
flux, the white flux, or the black flux. Crude flux is a mixture of nitre and
tartar, which is put into the crucible along with the metal intended to be fused.
White flux is formed by projecting equal parts of a mixture of nitre and tartar,
by moderate proportions at a time, into a red hot crucible. In the detonation
which ensues, the nitric acid is decomposed and flies off with the tartaric acid,
546 FOIL.
and the remainder consists of the potash in a state of considerable purity.
Black flux consists of two parts of tartar to one of nitre, on which account the
combustion is incomplete, and a considerable portion of the tartaric acid is
decomposed by mere heat, and leaves behind a quantity of charcoal, on which
the colour depends. It is used in the reduction of metallic ores, which it
effects by combining with the oxygen of the oxide. Mowean's reducing flux
is made of eight parts of pulverized glass, one of calcined borax, and half
a part of charcoal. Care must be taken to use a glass which contains no lead.
FLY, in Mechanics, a wheel with a heavy rim, placed on the shaft of any
machinery put in motion by any irregular or intermitting force, for the purpose
of rendering the motion equable and regular by means of its momentum. This
effect results from a law of nature, that all bodies have a tendency to continue
in their state either of motion or of rest, until acted upon by some extraneous
force. Thus the rim of a fly-wheel, after a few revolutions, acquires a
momentum sufficient to cause it to revolve with a velocity depending upon the
resistance of the machinery; and the augmentations and diminutions of the
impelling power succeeding each other rapidly, neither cause acts sufficiently
long to either augment or diminish the velocity acquired in any considerable
degree, so that it remains equable, or nearly so. Thus in the case of a man
working at a winch, the power which he exerts in pulling upwards from the
lower part considerably exceeds his power in thrusting forwards in the upper
quarter; but before the extra force thus exerted has acted sufficiently long to
change the velocity of the wheel, the winch arrives at the point where his force
is the least, by which time the excessive force previously exerted having taken
effect, the equable motion of the fly is maintained; and the resistance of the work
being equalized, a man is enabled to raise throughout a whole day a weight of
forty pounds with more ease than he could raise thirty pounds without a fly. In
all cases where a rotatory motion is to be obtained from a reciprocating one, by
means of a crank, a fly-wheel is necessary to continue the motion at those two
points of the revolution in which the crank lies in the direction in which the
moving force acts; for in this case the crank affords no leverage to the power
either on one or other side of the fulcrum, and consequently no motion could
be produced in either direction; but the momentum acquired by the fly urges
the crank forward in the direction in which it was previously moving, and con-
tinues the rotation until the crank is brought into such a position as to offer
sufficient leverage to the power to maintain the impetus of the fly.
FOCUS, in Optics, a point wherein several rays concur or are collected,
after having undergone either reflection or refraction. The point is thus deno-
minated because the rays being here brought together and united, their joint
effect is sufficient to burn bodies exposed to their action; and hence this point
is called the focus, or burning point.
FOIL, among jewellers, a thin leaf of metal placed under a precious stone,
in order to increase its brilliancy, or give it an agreeable and different colour.
These foils are made of either copper, gold, or gold and silver together; the
copper foils are commonly known by the name of Nuremberg, or German foils.
They are prepared as follows:–Procure the thinnest copper plates you can get;
beat these plates gently upon a well polished anvil with a polished hammer, as
thin as possible; and placing them between two iron plates as thin as writing
paper, heat them in the fire; then boil the foils in a pipkin, with equal quan-
tities of tartar and salt, constantly stirring them, till by boiling they become
white; after which, taking them out and drying them, give them another
hammering, till they are made fit for your purpose; however, care must be
taken not to give the foils too much heat, for fear of melting, nor must they be
too long boiled, for fear of attracting too much salt. The manner of polishing
is as follows:—Take a plate of the best copper, one foot long and about five or
six inches wide, polished to the greatest perfection; bend this to a long convex,
fasten it upon a half roll, and fix it to a bench or table; then take some chalk,
washed as clean as possible and filtered through a fine linen cloth, till it is as
fine as you can make it; and having laid some on the roll, and wetted the
copper all over, lay your foils upon it, and with a polishing stone and the chalk,
FORCE. 547
.*
polish your foils till they are as bright as a looking glass: after which they
must be dried, and laid up secure from the dust.
FOOT. A measure of length, consisting of twelve inches, each inch being
three barley corns, or twelve lines. The square foot is a measure for surfaces,
being a square of which each side is 12 inches; consequently a square foot
contains 144 inches. The cubic foot is a measure for capacity, or solid
contents; it is a foot in length, in breadth, and in depth or thickness, and
contains 1728 cubic inches.
FORCE is the name applied in Mechanics to whatever produces motion or
pressure. . Thus we have the forces of gravity and of elasticity, muscular
force, and that of electricity and magnetism. These will be considered
under the head PRIME Movers; at present we shall confine ourselves to the
general laws to which the application of force is subject. When a force is
applied suddenly to a body, and immediately ceases to act upon it, it is called
an impulsive force; but when its action is continued so as to produce a con-
stantly increasing motion or pressure, it is termed a constant or accelerating
force. Examples of the first kind are seen in the blow with a hammer, and in
the discharge of a gun ; and of the second, in the action of gravity and in
the motion of the wind. Impulsive forces produce uniform velocities. Thus,
if a billiard ball be struck, and move along a smooth table, so that the resistance
arising from friction may be small, it will be observed to pass over equal spaces
in equal successive portions of time; or, in other words, if the ball pass over
1 foot in a second, it will pass over 2 feet in two seconds, 3 feet in three
seconds, and so on. Constant forces produce accelerated velocities. Thus, if a
certain force, as that of gravity, act upon a body so as to impel it through 16
feet in one second of time, in the next second it would pass through three times
sixteen, or 48 feet; in the third second through five times sixteen, or 80 feet,
and so on, the constant addition being 32 feet, which is the velocity acquired
at the end of the first second of time. Now if a force produce an uniform
increase of velocity, as in this case, it is called an uniformly accelerating force;
or if it produce a regular diminution of velocity, it is a uniformly retarding
force. If, however, the increase or decrease of velocity be not constantly the
same, it is caused by a variable accelerating or retarding force. In the appli-
cation of forces, the chief considerations are intensity and direction. If a
single force act upon a body, motion necessarily results in the direction in which
the force acts, and with a velocity proportional to its intensity. If two or more
forces are employed, motion may or may not result, according to the intensity
and direction of the force. If two equal forces applied to the same point act
in opposite directions, they mutually annihilate each other; if, however, they
act in the same direction, they produce the same effect as a single one equal in
intensity to the sum of the two. Or, if they act in different directions, forming
an angle with each other, a third force may be assigned, which shall be equi-
valent to the other two. In this case the two forces are called the components,
and the third, the resultant. The process for finding the resultant of two or
more forces is called the composition of forces, and the finding of two or more
forces, which shall be equivalent to a single given force, is termed the resolution
of forces. The propositions connected with this subject form a highly inte-
resting and important branch of the science of mechanics. In the annexed cut
let the line A B represent the intensity and direction of
one force, and A C the intensity and direction of the A C
other force. Complete the parallelogram A B D C, and
the diagonal A D will represent the intensity and direc-
tion of the resultant; i.e. a force equal to A D, and, in
the direction DA, would counterbalance the other two,
and keep the point A at rest. The same may perhaps B ID
be more clearly apprehended by considering the point
A in motion; let a force act upon A so as, if alone, to drive it to the point B in
one second, and at the same instant let a force act in the direction. A C, that
would, if unopposed, carry it to C in the same time; then if the two forces act
together, the resulting motion will be in the line A D, and the body will reach

548 I'ORCE.
the point D in the same time that it would have taken to reach B or C by the action
of either of the forces singly. In the composition of forces it will be seen that we
are limited to one resultant; but in the resolution of force we may have an infinite
number of components, any pair of which will be equivalent to the given force.
Thus let a force, represented by the line A B, be
resolved into two others by drawing two parallelo-
grams around it, it will be manifest that the com-
ponent forces may be either A C and A E, or A D
and A. F.; and as an infinite number of directions
may be given to the lines AC, A E, the number of
components is also unlimited. In general, however,
the required direction and intensity of one of the
forces is given, and this determines the other.
Suppose a man were required to raise a weight over
a pulley, and the ropes, instead of being parallel, are
in the directions A B A D, it will be evident that a
part of his strength is employed uselessly in pulling
horizontally. Let B D represent the force necessary
to sustain the weight B; resolve this into the two
B C, B D, the one perpendicular, and the other parallel
to the horizon, it will then be seen that the force
which is employed in raising the body, is equal to
BC, and as this is less than B D, the weight must fall, *
or the power be increased in the ratio of B C to B D.
If three forces are employed, they may also be deter-
mined by drawing three lines parallel to their directions, so as to form a
triangle. The three cords A D, BD, CD, will be kept at rest, when the three
weights at A B C are proportional to the
three lines D E, D F, and E F, either of
which may be considered as the resultant of
the other two. If a number of forces act
upon a body, and a single resultant be re-
quired, it may be found by finding the
resultant of one pair, and connecting this
with another; then find the resultant of this
pair and connect it with the next, and so on,
till the last is obtained, which is the common
resultant of the whole. Numerous examples
are daily presented of the composition of
forces. When a boat is rowed across a river
in which there is a rapid current, it will not
pass directly across, nor down the stream,
but will partake of both directions, proceeding in a direction intermediately
between the acting forces. A body falling from the topmast of a vessel in full
sail will not fall directly downward, for having a direction forward given by the
motion of the vessel, and a downward direction by gravity, it will take a
middle course, describing what is termed a parabolic curve. The tide and
wind acting together upon a vessel, the two oars of a boat in rowing, the
motion of a stone, an arrow, or a cannon ball through the air, are examples of
the same kind. Another instance of a resultant motion may be adduced, in
the reflection of elastic bodies from a smooth
surface. Let A B be a smooth flat surface, A D ;B
and let an elastic ball strike it in the direc- :
tion CD, then will it be reflected in the
direction DE, making the angle of reflection
E D F equal to the angle of incidence C D F.
If C D represent the force of the ball in the :
direction CD, it may be resolved into two, E. f C
which are proportional to C F and C. B. The
force C F being parallel to the plane A B, is not influenced by it, but CD being



FORGE. 549
perpendicular, is destroyed, and a motion impressed in the direction D F. The
body is still then under the influence of two forces, its retained velocity in the
direction D A, and, the impressed force produced by the reaction of the board
in the direction D F. Between these two the ball necessarily moves in the line
D E. An application of this problem will account for the motion of billiard
balls, and of ships sailing obliquely to the wind; also of windmill sails, and
other daily occurrences in nature and art.
FORCEPS. A general term, (but principally used in surgery,) for a variety
of instruments of the nature of tongs or plyers.
FORGE properly signifies a little furnace, furnished with a pair of bellows to
render the combustion more vivid; and employed by smiths and other artisans
in iron, steel, &c. to heat their metals, in order to soften and render them more
manageable upon the anvil. In laboratories there is generally a small furnace,
consisting of a cylindrical piece, open at top, which has at its lower end a hole
for receiving the nozle of a pair of double bellows. This kind of forge is very
convenient for fusions, as the operation is quickly performed, and with few
coals. The natives of Ceylon work with considerable skill and taste in gold
and silver; and, with means that appear very inadequate, execute articles of
jewellery that would certainly be admired, but not very easily imitated in this
country. The best artists require only the following apparatus and tools, a
low earthen pot, full of chaff or saw dust, in which he makes a little charcoal
fire; a small bamboo blow-pipe, with which he excites the fire; a short earthen
tube or nozle, the extremity of which is placed at the bottom of the fire, and
through which the artist directs the blast of the blow-pipe; two or three small
crucibles made of the fine clay of ant-hills, a pair of tongs, an anvil, two or three
small hammers, and a file; and to conclude the list, a few small bars of iron or
brass, about two inches long, and differently pointed for different kinds of work.
3
It is astonishing what an intense little fire, more than sufficiently strong to melt
gold and silver, can be kindled in a few minutes. Such a simple forge deserves
to be better known; it is, perhaps, even deserving the attention of the scien-
tific experimenter, and may be useful to him when he wishes to excite a small
fire larger than can be produced by the common blow-pipe, and he has not a
forge at command. The success of this little forge depends a good deal in the
bed of the fire being composed of a combustible material, and a very bad conductor
of heat. The blacksmiths of Ceylon are not behind their brethren, the jewellers,
in the simplicity of their apparatus, however inferior they may be in skill.
The cut in the next page represents two smiths at a forge. The bellows consist
of a couple of bags made of bullocks' hides, each furnished with a bamboo nozle,
and a long slit as a mouth, with wooden lips, that are opened and drawn up and
shut and pressed down alternately by the hands of the person sitting between
the pair, who keeps up a constant blast by the alternate action of the two. The
mozle of the bellows is introduced through a small hole in the foot of the
screen, which constitutes the back of the forge, and serves to allow the ascent

4 A
550 FORGE.
of the smoke. It is composed of a mat or hurdle, supported between two
sticks, and plastered over with clay to protect it from the heat, Mr. J. Sperne,
of Belper, near Derby, has invented a forge, principally designed for the manu-
facture of nails, which is highly deserving of notice. It is peculiarly adapted
for the burning of charcoal; and the inventor proposes to adopt this fuel in
conjunction with coke, or coal purified from sulphur, generally in the proportion
of three parts of the latter to one of the former; these proportions to be, how-
ever, varied according to the nature of the coal, and the quality of the metal
to be wrought. This forge is constructed as follows:—the brickwork is first
carried up from the bottom of a cylindrical figure, to the height of twenty-four
inches, leaving proper apertures for the delivery of the ashes, the reception of
the water troughs, and for the insertion of the nozle of the bellows; the
circular aperture in the centre is then covered with a fine cast-iron grating,
which forms the bottom of the furnace. The courses of brick-work are next
carried up a foot higher, and the whole is then surmounted by a cast-iron plate,
with a rim or border six inches high round the external periphery, forming a
convenient dish for holding the fuel to replenish the fire. In the centre of the
cast-iron top plate is an aperture corresponding with the fire-place, and to this
aperture is fitted a cast-iron ring, supporting, on three cast-iron pillars, another
ring which carries the brick-work of the chimney, which is cylindrical. The
bellows are suspended from a frame, and are worked by a lever which encircles
the chimney, affording every workman employed the convenience of acting
upon it with facility; and as this construction of the forge will admit of six
workpeople being employed round it in making of nails, the fire is always
kept up bright and vivid by the continual blasts from the bellows. With
respect to the advantages of the forge the inventor observes—“By the peculiar
construction of the fire-place, wood charcoal alone may be used, which cannot
be done in other forges; but by a mixture of wood charcoal with coke for
fuel, the metals to be wrought will acquire a surprising degree of malleability,
and weld with great ease; their tenacity and clearness will also be improved,
and they will have, when cold, a better face or skin than can be put upon them
by any other method. In addition to the great advantage of apportioning the

FOUND IN G. 551
fuel to the work required, the circular form will admit of a greater number of
workmen being employed at the same time at this forge than at any other,
thereby causing a saving of brickwork in the erection of forges, of bellows,
and shoproom for working them, and a permanent saving in the fuel for their
consumption. See IRoN.
FORK. A well-known instrument, consisting of a handle, and two or more
prongs. Though considered now to be indispensable, it did not come into use
till the reign of James I.
FORM. In Printing, an assemblage of letters, words, and lines, arranged
in order, and disposed into pages by the compositor; from which, by means of
ink and the press, sheets are printed. Every form is enclosed in an iron chase,
wherein it is firmly locked by a number of wedge-shaped pieces of wood of
various sizes. There are two forms required in every sheet, one for each side:
and each form consists of more or fewer pages, according to the size of the
book. See PRINTING.
FORMIATES. Compounds of the formic acid with earths, alkalies, and
metallic oxides.
FORMUL.A. A general rule or expression for resolving certain particular
cases of some problem.
FOTHERING. A method sometimes resorted to for stopping a leak in a
vessel at sea. It consists in stitching loosely a quantity of oakum upon a sail,
which is drawn under the vessel's bottom; and by the flow of the water through
the leak, the oakum is drawn into the aperture.
FOUNDING is the art of casting or forming of melted metal an infinite
variety of articles to any given pattern or design; and the place or building
where the art is carried on is called a foundry. Foundries are, however, dis-
tinguished either by the metals they work or the articles they fabricate, such
as brass foundries and iron foundries, bell and type foundries. As the
methods of casting in one kind of metallic substance are very similar to those
employed in others, we shall therefore describe at some length the art of
founding as it is practised by the brass founders, and more briefly whatever is
peculiar in the processes adopted in the other branches of the art.
The operations of the brass founder are not limited to that peculiar yellow
compound of copper and zinc, strictly termed brass, but to every variety of the
alloys of copper, with tin and zinc in every proportion, according to the pur-
poses for which the article is required, or according to the motive of economy
or profit of the manufacturer. Founders in brass require an exact model in
wood, or otherwise, of the article to be founded; and this is most frequently
made in two parts, exactly joined together, and fitted by small pins, and the
casting, in such a case, is performed by two operations, that is, one half at one
time, and one half at another, and in the manner following ; viz. the founder
provides himself with a yellowish sharp sand, which is required to be well washed,
to free it from all earthy and other particles. This sand is prepared for use
by a process called tewing, which consists in working up the sand in a moist
state, over a board about one foot square, which is placed over a box to receive
what may fall over in the tewing. A roller about two feet long and two inches
in diameter is employed in rolling the sand about until it is brought into that
state which is deemed proper for its business; a long-bladed knife is also
required to cut it in pieces. With the roller and the knife, the tewing is
finished for use by being alternately rolled and cut. When the sand is so far
prepared, the moulder provides himself with a table or board, which, in size,
must be regulated by the castings about to be performed on it. The edges of the
table or board are surrounded by a ledge, in order to support the tewed stuff;
the table, so previously prepared, is filled up with the sand as high as the top of
the ledge, which is in a moderately moistened state, and which must be pressed
closely down upon the table in every part. When the operation has so far
advanced, the models must be all examined, to see that they are in a state to
come nicely out of the mould, and if not found so, they must be cleaned or
altered till the founder is satisfied with them. All models require the greatest
accuracy in their making, or it will be vain to suppose any thing good can be
552 FOUND IN (3.
performed by the founder. When the models are in a proper state to be
founded, one half, generally longitudinally, is taken first, and this is applied on the
mould, and pressed down into the tewed stuff or sand, so as completely to leave
its form indented on it, which must be very carefully looked to, and examined
minutely, to see that there are no small holes, as every part in the indented
sand must be a perfect cameo of the models submitted and pressed into it. If
it should not be found perfect, new sand must be added, and the model re-
indented and pressed into it, till it leaves its impression in a state proper to receive
the metal. In the same manner, other models intended to be founded on the
same table must be prepared and indented into the sand. When the table is
completely ready for the metal it is carried away to the melter, who himself
examines its state, and also the cameos, and who lays along the middle of the
mould the half of a small wire of brass, which he presses into the sand, so as
to form a small channel for the melted brass to flow in, and which he terms the
master jet or canal. It is so disposed as to meet the ledge on one side, and far
enough to reach the last pattern on the other; from this is made several lesser
jets or branches, extending themselves to each pattern on the table, by
which means the fluid metal is conveyed to all the different indented impres–
sions required to be cast on the table. When the work is so far forwarded it
is deemed ready for the foundry; but previously to this, the whole is sprinkled
over with mill dust, and when it is so sprinkled the table is placed in an oven
of moderate temperature till it gets dry, or in a state which is deemed proper
to receive the melted brass. The first table being thus far completed, it is either
turned upside down, and the moulds or patterns taken out, or the moulder
begins to prepare another table exactly similar to the one he has just com-
pleted, in which he indents and presses the other half of the mould ; or he turns
the table already finished, containing the first half of the patterns, upside
down; previously, however, to doing this, it will be necessary for him to
loosen the pattern, which is fixed in the sand, a little all round, with any small
instrument that will open away the sand from its edges, in order to its coming
out of the table more easily. This economy in founding, of making one
half of each pattern to be cast answer the purpose of the whole pattern, is a
very common practice in brass founding, and enables the manufacturer to sell
his goods at a much cheaper rate than he would otherwise be enabled to do if
he was obliged to have a full pattern of all goods to be founded. When he has
loosened the sand from about the pattern, and taken it out of the first table, the
work is proceeded in of preparing the counterpart or other half of the mould
with the same pattern, or otherwise, and in a frame exactly corresponding with
the former, excepting only that it is prepared with small pins to enter holes
which are made in the first half of the model, to secure them together.
When this counterpart table has been finished, and all the patterns indented in
the sand, it is carried to the melter, who, after enlarging the principal jet of the
counterpart, and making the cross jets to the various patterns, and sprinkling
them as before with mill dust, it is set in the oven to be sufficiently dried to
receive the liquid metal. When both parts are sufficiently dry, they are joined
together by the pins, and to prevent these from being forced open by the pressure
of the liquid metal, the tables are further secured by screwed bolts or wedges.
The furnace for melting is somewhat similar to a smith's forge, with a chimney
over it, and a pair of large bellows; the hearth is of masonry or brickwork,
secured by an outer rim cf iron. The fire-place, which is in the centre, is a
cavity of 12 to 18 inches square, and reaching down to the floor of the foun-
dry. The lowest part of this cavity constitutes the ash-pit and air-chamber, and
is divided from the upper portion by an iron grating; on this the fuel is deposited,
in the centre of which is placed a covered crucible, containing the metal
under fusion, which is accelerated by keeping the fuel in which it is completely
imbedded in vivid combustion by the continued action of the bellows. When the
fusion is perfect the crucible is withdrawn from the fire by the caster, with a pair
of long tongs adapted to gripe it firmly, and with which he pours into the master
jet of each mould until they are filled. As soon as this is done water is sprinkled
over the tables to cool and fix the metal; after which the tables are unfastened,
FOUNDING, 553
and the new castings taken out, to be finished by filing, scouring, burnishing,
turning, &c. as the work may require. The sand is now taken out of the frames,
to be worked up again for the next casting; by repeated use the sand becomes
black, by the charcoal collected from the foundry, which does not, however,
unfit it for further employment. To reduce the expense and weight of casting
large masses in solid metal, recourse is often had to forming them hollow,
which process is distinguished by the term core casting, as it is necessary to
have a core or heart of nearly the shape of the external form of the pattern.
This core is usually made of clay, mixed and kneaded with crucible dust, and
is suspended by wires in its place, with a space around it to receive the
metal; in small articles, however, it is usual to fill up the space by coating the
core to that extent with wax, which melts as the metal flows to supply its
place. When the pattern is of a complicated form, and a difficulty arises in
getting out the core, it is usually separated into several pieces, which are
joined together after being cast. In many of the Birmingham manufactures
the cores occupy so much of the pattern, that the metal left is not thicker than
a shilling. The business of a brass founder, contrary to that of an iron-
founder, extends to the finishing of the articles he casts; and not only to this,
but to the manufacture of brass goods that are not cast or founded at all, being
made entirely from wrought or rolled metal. A large proportion of the Bir-
mingham manufacture of cabinet brass work is formed out of sheet metal, by
pressure between dies after the manner of coining: such goods are in con-
sequence cheaply made, and frequently are impressed with very tasteful and
elaborate designs. The castings, when taken out of the sand, have first to be
cleaned up and completed, as they are seldom free from defects; the cores are
filed off, and the small cavities filled up with metal or solder; they are after-
wards finished, according to the nature of the article, by filing, turning, bur-
mishing, and lackering. The superior kinds of brass work are gilded,
which preserves them better than lacker, and constitutes the article called
or molu.
In the founding of statues, busts, &c. three things in particular require atten-
tion ; namely, the mould, the wax, and shell or coat, the inner mould or core,
so called from being in the middle or heart of the statue. In preparing the
core, the moulder is required to give it the attitude and contour of the figure
intended to be founded. The use of the core is to support the wax and shell,
to lessen the weight, and save the metal. The core is made and raised on an
iron grate, sufficiently strong to sustain it; and it is farther strengthened by
bars or ribs of iron. The core is made of strong potter's clay, tempered with
water, and mixed up with horse-dung and hair, all kneaded and incorporated
together; with this it is modelled and fashioned previously to the sculptor's
laying over it the wax; some moulders use plaster of Paris and sifted brick-
dust, mixed together with water, for their cores. The iron bars which support
the core are so adjusted that they can be taken from out of the figure after it
is founded, and the holes are restored by solder, &c.; but it is necessary in full
sized figures to leave some of the iron bars affixed to the figure to steady its
projecting parts. After the core is finished, and got tolerably firm and dry, the
operation of laying on the waxen covering to represent the figure is performed,
which must be all done, wrought, and fashioned, by the sculptor himself, and by
him adjusted to the core. Some sculptors work the wax separately, and afterwards
dispose and arrange it on the ribs of iron, filling up the void spaces in the middle
afterwards with liquid plaster and brick-dust, by which plan the core is made as, or
in proportion to, the sculptor's progress in working the wax model. Care must be
taken, however, in modelling the wax in both cases, to make it of an uniform
substance, in order to the metal being so in the work, of which the wax is its
previous representative. When the waxen model is finished to the core, or
adapted and filled afterwards, small tubes of wax are fixed perpendicularly to
it from top to bottom, to serve not only as jets to convey the melted metal to
all parts of the work, but as vent holes to allow a passage to the air generated
by the heated brass in flowing into the mould, and which, if not admitted
readily to escape, would occasion so much disorder in it as would much injure
554 FOUND IN G.
the beauty of the work. Sculptors adjust the weight of the metal required in
this kind of founding by the wax taken up in the model. One pound of wax
so employed will require ten pounds of metal to occupy its space in the cast-
ing. The work having advanced in progress so far, will now require covering
with a shell. This consists of a kind of coat laid over the wax, which, being of
a soft nature, easily takes and preserves the impression, which it afterwards
communicates to the metal upon its occupying the place of the wax, which is
between the shell and core. The shell is composed of clay and white crucible
dust, well ground, screened, and mixed up with water to the consistence of paint,
like which it is used. The moulder applies it, by laying it over the wax with
a camel's hair or other soft pencil, which will require eight or nine times going
over, allowing it time to dry between each successive coat. After this coating
is firm upon the wax, and which is used only to protect it from those
which are to follow, the second part or coating is made up of common earth,
mixed with horse dung; this is spread all over the model, and in such thick-
ness as to withstand, in some measure, the weight of the metal. To this
coating or impression is added a third, composed almost wholly of dung, with
a proportion of earth sufficient only to render it a little more tough and firm
when used. When this is tolerably dry, the shell is finished by laying on
several more coats or impressions of the same composition, made strong and
stiff by successive workings with the hand. When this is finished and is
deemed adequate to support the heated metal, it is further secured and
strengthened by several bands or hoops of iron, bound round it at about six
inches from each other, and fastened at bottom to the grate on which the statue
stands. Above the head of the statue is made an iron circle, for the purpose
also of confining the shell and statue; to this circle the hoops are fastened at top.
It may be considered, when the moulding has arrived at this state, to be in a
condition to receive the melted metal; but it is not so exactly, as will soon
appear. The mould, as has been before observed, is made upon an iron grate;
under this grate is a furnace and flue, in which, at this period of the work, a
moderate fire is to be made, and the aperture of communication therewith
stopped up, so as to keep in the heat. As the heat increases and begins to
operate upon the mould, preparation must be made to allow of the wax running
freely from out of the shell; for this purpose pipes are contrived at the base of
the mould so that it may run gently off and through these pipes. As soon as it
is all run off the pipes are nicely stopped up with earth to prevent the air
entering them, &c. When this is done the shell is surrounded by any matter
that has non-conducting properties—for instance, pieces of brick put round
and piled up of good thickness, secured by earth, will answer the end; and the
whole should be finally coated outside with loam as a further protection to
keep in the heat. After the shell is adequately surrounded with materials to
keep off the effect of the air, the fire in the furnace is augmented till such
time as both the matter surrounding the shell and it also becomes red hot, and
which, in ordinary circumstances, will take place in twenty-four hours' time;
the fire is then extinguished, and the whole allowed to cool; after which, the
matter which has been packed round the shell is taken away, and its place
occupied with earth moistened and closely pressed to the mould in order to
make it more firm and steady. It will, when having advanced so far, be in a
state to receive the melted metal, to prepare which for the casting, a furnace
is made a few feet above the one employed to heat the mould; it is formed
like an oven, having three apertures, one of which is for a vent, the other to
admit the fuel, and the last to let the melted metal flow through and out of the
furnace. This last aperture should be kept very close whilst the metal is fusing,
when it has arrived at that state which is deemed proper for running it into
the shell, and which is known by the quick separation and escape of the zinc
of the brass. A little tube is laid to convey it into an earthenware basin, which
is fixed up over the top of the mould ; into this basin all the large branches from
the jets enter, and from which is conveyed the metal into all parts of the
mould. The jets are all stopped up with a kind of plugs, which are kept close
till the basin which is to supply the metal be full. When the furnace is first
FOUND IN G. 555
opened for this purpose the melted brass gushes forward like a torrent of fire,
and is prevented from entering any of the jets by the plugs, till the basin is
sufficiently full to be ready to begin with the mould, and which is esteemed so
when the brass it contains is adequate to the supply of all the jets at once,
upon which occasion the plugs from all of them are withdrawn. The plugs
consist of a long iron rod, with a head at one end, capable of filling the whole
diameter of each tube. The hole in the furnace in which the melted metal is con-
tained is opened with a long piece of iron fitted on the end of a pole, to allow
of the furnace man keeping at a distance from it, as many accidents occur by
the red hot metal coming in contact with the air, particularly if it be damp, in
which case the most violent explosions take place. The basin is filled almost
in an instant after the furnace plug is withdrawn, and the metal is then let into
the several jets communicating with the model, which, when they have emptied
themselves into the shell or mould, the founding is finished in so far as the
casting is concerned. The rest of the work is completed by the sculptor, who
takes the new brass figure from out of the mould and earth in which it was en-
compassed, saws off the jets, and repairs and restores the parts where required.
His tools for this purpose consist of chisels of various sizes, gravers, punches,
files, &c.
In casting colossal statues a somewhat different mode is pursued than the
one already described, and this arises wholly from the size, it being found diffi-
cult to remove the moulds of such colossal works; to obviate this difficulty, it
is worked and prepared upon the spot where it is to be cast. There are two
ways of performing this, and some founders prefer the one and some the other.
By the first plan, a square hole is dug into the earth somewhat larger than
would be required for the mould, and its sides are hemmed up with brick-
work; at its bottom is formed a hole, below the one already prepared, as a
furnace, which must be built up with brickwork, having an aperture made
outwards into another pit prepared near it, from which the fuel is put into the
furnace. The top of the furnace in the first hole is covered by a grating of
iron, and on this is moulded and placed the case of the statue to be cast, and
also its waxen coating; in doing which the same process is observed by the
sculptor as that already described. Near the edge of the large pit in which
the model is placed is erected the furnace to melt the metal, and which is
similar to the one already described for common figure casting, except being of
larger dimensions; it has, like that, three apertures—one for putting in the wood,
another for a vent, and a third to run the metal out at. By the second plan of
founding colossal figures, it is thought sufficient to work the model above
ground, adopting the same mode with respect to a furnace and grate under-
neath it; for whether under ground or above it, to keep in the heat when
drying the core and melting the wax, is the end more particularly sought;
to do which in the most effectual way four walls of brickwork are built
up round the model, in the middle of which is fixed the grate and furnace;
and on one side above is formed the mass of building intended for the furnace,
which is to be appropriated to the melting of the metal. When the whole is
finished and ready, a fire is made in the fire-place under the core of the model,
and kept up so as to produce a moderate heat to dry the core, and also to melt
the wax from off it, which runs down by tubes, as has been before remarked,
and indeed no difference whatever takes place in such founding, except
every thing being upon a larger scale. When the wax is run off and the fire
extinguished in the furnace, bricks are filled in at random, either into the hole,
if founding under ground, or into the area between the walls, if above ground;
after this is done, the fire in the furnace is again lighted, and blown up and
augmented till such time as both the core and bricks are of a red heat, when
the fire is again extinguished, and the whole is left to cool; and when cooled,
the bricks are removed, and all is cleared away, and the space again occupied
by moistened earth to secure and steady the model. Nothing now remains but
running in the metal, which is performed, as has been before described for
smaller foundings of statues.
The casting of guns is performed in the Inanner already described for statues,
556 FOUND ING
excepting that no core is required, it being cast solid, and the cavity entirely
bored out, during which operation the gun is turned and finished on the outside.
(See CANNoN, and BoriNG MACHINE.) The composition of which cannon is
formed in this country is 10 lbs. of tin to 100 lbs. of copper, whereas, in the
brass of statues, zinc is employed instead of tin. © g
Founding in Bronze.—The Egyptian bronze consisted, according to Bessari,
of two-thirds brass and one-third copper. Pliny says, that the Grecian bronze
was formed by adding one-tenth lead and one-twentieth silver to the two-thirds
of brass, and the one-third of copper of the Egyptian bronze; and that this was
the proportion afterwards made use of by the Roman statuaries. The modern
bronze is commonly made of two-thirds copper, fused with one-third of brass;
and recently, owing to the great demand for ornaments and decorative furniture
of this alloy, lead and zinc in small proportions have been added to the copper
and brass. These additions, it is said, increase the fusibility of the alloy, and
facilitate the process of casting. Bronze casting is employed in forming eques-
trian statues, colossal and other figures in alto relievo, to adorn public places, its
peculiar tint finely contrasting with the stone or marble of architecture, espe-
cially when the artist displays taste in his design and skill in his execution.
The casting in bronze is performed in the following manner: first, the figure or
pattern to be cast must have a mould, and this is prepared and laid on a plaster
cast, previously wrought and finished by the sculptor. The mould is made of
plaster of Paris, moistened with water, to which is added brick-dust in the
proportion of one-third of the former to two-thirds of the latter. This is
carefully laid on the mould, with strength in proportion to the weight of metal
intended to be used in the founding. In its joints should be cut small channels
tending upwards and from different parts of the internal hollow, to allow of
vent for the air to escape, as the heated metal runs in upon the mould.
A thin layer of clay should be spread over the inside of it, and of the
thickness which it is intended the bronze should be. Withinside of the clay a
filling-up of plaster and brick-dust, in the proportions as before described, will
be required to compose the core; but if the work to be cast be large, before
the plaster and brick-dust are poured into the mould to form the core, a skeleton,
composed of iron bars, as a support for the figure, should be prepared and fixed;
after which the filling up of the core may be proceeded in. When this is done
the mould must be opened again, the layer of clay taken out of it, and the
core thoroughly dried, and even burned, with a charcoal fire, or with straw;
for if the least damp remain the cast will be blown to pieces when the hot
metal comes in contact with it, in running it into the mould, and the workmen
employed about the work be maimed or killed by the dispersion of the heated
bronze. After the core, &c. has been properly dried and is deemed ready for
the work, it should be laid in the mould, and supported in its place by short
rods of bronze, which should run through the mould into the core. All being
so far advanced, the mould should be clad and bound round with iron, of
strength proportionate to the size of the work to be cast; after which the
mould should be laid in a situation for running in the metals, and must be
supported for that purpose by bricks, &c. Great care should be taken that
every part be perfectly dried before any metal be run into the mould, or, as has
been before observed, the most fatal consequences will arise to those who may
be about the work. A channel must be made frôm the furnace in which the
melted metal is, in order to its running to the principal jet of the mould, and
with a descent to promote its flowing rapidly. The jets, furnace, &c. &c. are
all contrived, as has been before described, for casting figures in brass.
Founding of Iron.—Owing to the immense demand for cast iron in most of
our great public works, such as bridges, rail-roads, columns, girders, fences, gas
and water pipes, house-building, framing of machinery, and innumerable objects
of less magnitude, iron founding has become one of the most interesting and
important of our national manufactures. Wherever a foundry is to be formed,
a dry situation should be selected for it, as dampness would totally prevent any
thing being cast with tolerable accuracy, besides rendering the founding, in such
places, dangerous to the workmen employed. The floor of a building for this
FOUND IN G. 557 .
business should be about ten feet deep, and composed of a kind of loamy sand;
and if the place selected does not afford this convenience naturally, the ground
must be made hollow, and such sand brought to fill up the excavation. This
loamy sand is for the purpose of burying large moulds beneath its surface, so
that the metal may be conveyed to them by channels or soughs hollowed out of
the sand, and through which it runs from the furnace to the mould to be cast.
A foundry, or casting-house, is provided with as many air or reverberating
furnaces, in addition to the blast furnaces, as is required for the extent of the
works to be founded at it; an air or reverberating furnace is only used occa-
sionally, either when the metal contained in the blast furnace is not sufficient,
or when the quality made in it is not proper for the work about to be cast.
The difference in the qualities of the metals arises from their containing too
much or too little carbon, and this is corrected by the founder, who mixes them
with better or worse metal till they are rendered fit for the purpose required.
Cupolas, as they are called, are also wanted in a foundry, and are similar to the
blast furnace, except being of somewhat smaller capacity; they are used to
melt small quantities of metal when it is wanted in haste, as the reverberatory
or blast furnaces will take more time in filling the charge of metal than the
cupola does, by reason of their being of larger capacity; but the founding by
cupolas requires more machinery, from which circumstance it is not so well
adapted to answer the purpose of the founder as the employment of a reverbe-
ratory or blast furnace. A much greater stock of flasks and other implements is
wanted to make the moulds with, than is required by the caster who performs
his work by means of either of the other furnaces ; these kinds of furnaces
are always in use at large foundries, as at such places can be employed the
whole charge of metal they are capable of containing. In a foundry worked
by a blast furnace, a pit is sunk at a convenient distance from it, and the
moulds for all large articles, such as pipes, &c. are placed vertically in it,
within reach of the crane, that they may be raised or lowered in the pit. The
metal is conveyed from the furnace by a gutter or trough made in the floor of
the foundry, and a small iron trough, filled with sand, conducts the fluid metal
into the moulds. This method of performing foundings at large works is an
improvement on the old one, (which consisted in burying the pattern in sand,)
and which has caused a great saving in labour and time. The flasks for this
method of casting are founded of iron. It is now a practice at most of our
large foundries to substitute sand for loam castings, in cases in which there are
a great number of articles of the same kind to be cast, so that the expense of
the flasks becomes an object of no great importance. When it happens that
the articles are intricate, the sand is wetted so much as to render it sufficiently
adhesive to make it mould, and receive the form of the pattern completely;
after this is done, it is necessary to dry the mould, to prevent accidents by the
explosion of the hot metal when running the cast; for this purpose stoves are
used in which an equal and moderate degree of temperature is produced, and of
a capacity adequate to contain a good number of the patterns. The moulds,
when ready to be dried, are placed upon a carriage adapted to the purpose, and
on which they are arranged and conveyed to the oven ; and when dry, which
generally happens in about half an hour, they are withdrawn, and a new set
placed upon the carriage. Every foundry should be provided with one or more
cranes, so placed as to be easily got at when it is required to raise, lower, or
remove, any large piece of casting. The moulding of large pieces of cast-iron,
when they are required to be hollow, is made in loam, and consists in laying
down an iron ring upon the ground, of the diameter of the proposed calibre of
the work to be cast, and which has a rod of iron in its centre; after this is done,
bricks, clay, and wet loam are mixed together, and built up within the ring and
round the iron rod, of somewhat less diameter than the cylinder about to be
cast, and for which this is to form the core. The whole, when built, is bound
round with iron hoops to protect it, and a fire is made inside to dry it; and when
properly dried, a coating of loam is spread all over and smoothed; this coat fills
up and makes it the proper size for the inside of the cylinder, and is called the
core of the mould. Another cylinder is built and plastered in the same manner,
4 B
#58 FOUNDING,
but without hoops, whose diameter is the same as the outside of the cylinder to
be founded. When this is finished, it is covered over with charcoal dust, or
ground charcoal, which is mixed up with water-like paint, and laid on with a
brush; and a thin coating of loam, mixed up with hair, is then laid over the
charcoal, previously spread upon the inner cylinder. When all these are quite
dry, a man gets into the cylinder, and with a picker pulls away from the core
the bricks, and then with a trowel cuts away also the loam, leaving the inside
of the external cylinder, which is called the mould, quite smooth; this part
of the work is effected by the coat of charcoal, which prevents the two coats of
loam from adhering together. While this is doing, a deep pit is dug, and into
this the core is let down by a crane; when this is done, the mould is lowered over
the core; as soon as the adjustment is perfected, sand is thrown in and rammed
round about it, to about the half of its height; after which a flat cover of dried
loam is put on the top of the mould and core, and pieces of rounded wood are
put into the holes, which had been before made for pouring in the metal. The
plugs which keep open these holes are carefully taken out, and small channels
prepared for the metal to run through from the furnace. Before the metal is
run into the mould, the latter should be carefully examined, to ascertain that it
is quite dry, and in other respects in a perfect condition to receive the metal.
Sand, or open casting, is used for such articles as will allow of cutting into two
pieces, or even more, the models of which are indented in the sand, and the
metal is run in between flasks.
A patent for an improved mode of casting metallic cylinders was taken out
in 1826 by Mr. William Church, of Birmingham, the object of which was to
produce perfectly sound castings of uniform solidity. The process consists in
exhausting the air from the moulds by means of an air-pump, and afterwards
in forcing the fluid metal, from an air-tight reservoir beneath, upwards into the
mould by the aid of a condensing pump. As the apparātus for this purpose
may be constructed in a variety of ways, and be adapted to the description of
articles to be cast, the patentee has described only one arrangement, which he
adopts and recommends for the purpose of casting large cylinders, rollers,
cannon, &c. The mould prepared for casting is enclosed in a cast-iron air-
tight casing, and suspended in a vertical position, by means of chains, to the
jib of an ordinary crane, over the vessel containing the fluid metal; to the
lower end of the mould, an earthen tube (the materials similar to the crucible
ware,) descends and forms the channel for conveying the metal upwards into
the mould at the proper period of time; this earthen pipe is covered with a cap
at its lower extremity, which is luted to it so as to be air-tight, and the material
and thickness of the cap is such that it will melt a short time after being im-
mersed in the fluid metal. As soon as the metal has arrived at the proper
temperature the suspended mould, with its appendage, as before mentioned, is
lowered by means of the crane, so that the earthen tube is immersed into the
liquid metal in the chest beneath; this metal chest is then closed air-tight with
a flange fixed on the upper part of the earthen tube, by proper contrivances
for that purpose, such as a conical rim, an elastic metal hoop and luting; the
perfect closing of which is effected by the pressure of the mould in its descent
to its seat on the top of the metal chest. The apparatus so far prepared is
next connected by short pipes with union joints, to pipes leading from an air-
#. of large dimensions, which both exhausts and condenses. First, the air
is exhausted from the mould, and from above the surface of the melted metal
in the chest; by this time the cap of metal at the lower end of the earthen
tube becomes fused, the fluid metal ascends that tube, and is then forced by the
condensing operation of the air-pump into the mould above, which, being pre-
viously exhausted, the metal is uniformly pressed into every cavity. . As the
vacuum in the mould is of course imperfect, from the previous exhausting ope-
ration, and the remaining portion of air becomes condensed by the rising of the
metal, to prevent any ill effects from its pressure, a stop cock, communicating
with the exhausting end of the air-pump, is opened, by which it is withdrawn.
For the purpose of rapidly cooling the mould after being filled with the liquid
metal, the cast-iron mould case is surrounded with an outer case or jacket, with
FOUNDING, 559
a vacant space between, which is charged with cold water whenever, desired,
as in some castings this application must be of great utility in hardening their
surfaces.
In 1825 a patent was taken out by Messrs. White and Sowerby for an air
furnace for melting iron, for the use of founders, in which the requisite degree
of heat is obtained without the necessity of resorting to mechanical aid, but
simply by the production of natural currents of air through lateral openings or
passages, with the further advantage of causing a body of flame to be con-
ducted over that portion of the metal lying in a fluid state at the bottom of the
furnace, by which it is kept from solidifying prior to the whole contents being
discharged. On these principles the patentees state that the furnaces may be
made square, round, oval, octagonal, or any other convenient form, with pas-
sages for the admission of atmospheric air in various parts and in different
directions, according as they may be required to direct the heat. The annexed
figures are intended to illustrate one convenient mode of carrying it into effect.
Plan.
a represents the body of the furnace, in which the coke and metal is deposited;
b and c are flues leading from the same into the vertical chimney d, the capacity
or depth of the flues is regulated by dampers e e : ff show the situation of two
of the lateral air chambers, (of which there may be any number;) one of these is
shown as opening into the outside of the structure, and the other into an open
archway or passage between the chimney and the body of the furnace; a man hole,
for clearing out the bottom or bed of the furnace whenever required, is situated
at g. To set the furnace to work, the cover h is removed, and coke or other
fuel thrown in, which may be lighted, if required, at either of the air passages ff;
when the heat has been raised to the proper degree for the fusion of the iron,
the metal and coke are thrown in alternately, in such quantities and proportions
as may be required for the casting, when the furnace is again to be closed by
the cover h. When the whole of the metal is reduced to the fluid state, it is
run off from the bed by means of a tap hole in the lower part. By the
arrangement of the furnace, it will be perceived that a body of flame is made
to operate upwards in melting the metal, and another takes a downward course,
passing over the bed of the furnace, preserving that portion of the metal which
has been already melted, and lying upon it, in a fluid state, until the whole
contents of the furnace are melted.
The founding of iron cannon is conducted in a similar manner to other cast-
ings; the pattern is meulded in the sand, and the metal run into the mould


560 FOUNDING.
through a gutter. Small guns are moulded on tables, one half of the mould
being formed on one table, and its counterpart on another; they are fitted
together by pins, and screwed up by nuts and bolts to keep them firm together
whilst the hot metal is run in. About fifty years ago cannons were cast with a
hollow cavity for the bore, which was afterwards enlarged and cleaned out by
a machine adapted to the purpose. Guns are now invariably cast solid, owing
to the difficulty of getting them perfectly sound by that mode of casting, being
more or less spongy in some parts, which the subsequent turning did not wholly
remove. For the method of boring and turning great guns, see the article
CANNoN. - -
The manner of casting bells is similar to that of statues, except that bell-metal
contains about one-fifth of tin to four-fifths of copper, while the metal of statues
contains no tin. The dimensions of the core and wax in modelling a bell, it
it be one of a ring of several, must be formed on a kind of scale or diapason,
which will give the height, aperture, and thickness of the shell necessary to the
several tones required. Our proportions of bells consist in making the diameter
fifteen times as thick as the brim, and its length twelve times. See the article
BELL, under its initial letter.
We now come to the description of that department of the foundry art which
must be regarded as the most valuable and important when its effects in ame-
liorating our condition as intellectual beings is considered : we allude to the
art of founding type. This invention is supposed to have originated at Mentz,
in the early part of the fourteenth century, when types were carved out of wood.
Some time afterwards they were cut of metal, and one Laurentius was honoured
as the inventor of this improvement, which, however trifling it may appear as
an advance in any mechanic art, proved to be of vast importance in its result.
The art of founding or casting types quickly succeeded, which appears to have
had its origin also in Germany, as we find they were first introduced into Hol-
land from Strasbourg. By the mercantile activity of the Dutch at this period
the new metal type was rapidly dispersed into all the capital cities of Europe.
The earliest use of them in this country was at Oxford, in 1468, when a book
was printed there by one Bouchier. F. 1471 Caxton, who had studied the art
in Holland and the Low Countries, established several printing presses in this
country. The art of reading, which, but a short time before, was chiefly con-
fined to a portion of the clergy and nobles, was soon extended to the other
gradations of society; and the ability to read was no longer considered the
highest climax and finish of an education, but was made the first step to it, by
the introduction of printed books into every school and seminary. As the
rudiments of education became improved, books became rapidly multiplied, print-
ing encouraged, and ever since a progressive improvement has been gradualty
developing itself. Until the seventeenth century types continued to be cast with
very few improvements, excepting such as arose from alterations in the form
of the letters. Caslon set up a foundry in 1720, and succeeded in making
several improvements, to which some valuable additions were added by Basker-
ville, of Birmingham. Messrs. Fry and Son's foundry was established in 1764
In 1770 Mr. Jackson cut some very extraordinary and beautiful types, by a
mould and matrix, which were previously cast in sand. Mr. V. Figgins, in
1792, produced some beautiful types for the Persian, Greek, and Hebrew
characters, never before attempted in this country. In 1800 Messrs. Caslon
and Catherwood set about recutting and improving the whole business; and
the superior taste and elegance displayed in their manufacture occasioned a
spirit of rivalry in the other type founders, particularly Messrs. Fry, Figgins, and
Thorne, who exerted themselves individually so as not to be surpassed by their
competitors; the effect of which has been the production of types of that high
degree of excellence, which marks the character of all our books printed since
that period. The preparation of the moulds and matrices for the purpose of
casting the letters requires the utmost precision of workmanship ; the matrix
itself is simply a piece of copper or brass, about an inch and a half long, and
of a thickness in proportion to the size of the letter to be cast. In this piece
of metal is sunk the face of the letter, by means of a steel letter-punch. These
FOUND ING. 561
punches being made with every size and kind of letter, are, of course, very
numerous; and the making of them, requiring the utmost nicety of execution,
necessarily forms a branch of the type-founder's business of considerable im-
portance. There are about twenty different sizes of each kind of type in general
use, all of which are cast in moulds and matrices, besides several larger sorts,
which are cast from patterns in sand. The following table gives the designation
of the twenty sizes alluded to, and the spaces they occupy in printing. They
are sold to the printer by the pound, at prices varying from two to thirteen
shillings, according to their size —
Lines to each foot. Lines to each foot.
Diamond type . . . . 204 Great Primer . . . . . 51
Pearl . . . . . . . 178 Paragon . . . . . . 44%
Nonpareil . . . . . 143 Double Pica . . . . . 41%
Minion . . . . . , 128 Two-line Pica. . . . . .353
Brevier . . . . . . 1 12# Two-line English. . . . 32
Bourgeois . . . . . 102 Two-line Great Primer. . 25.4
Long Primer . . . . 89 Two-line Double Pica . . 20%
Small Pica . . . . . 83 Canon . . . . . 18
Pica. . . . . . . . 71% | Four-line Pica. . . . , 17%
English . . . . . . 64 Five-line Pica. . . . . 14%
When the moulds and the set of matrices are duly prepared, they are brought
to the furnace, and consigned to the hands of the caster. The furnace is built of
bricks upright, with four square sides; the stove for the fuel is at the top, with
a round hole made through it, to receive the pan which holds the metal. In a
large foundry there are several of these kinds of furnaces. The caster begins
his work by taking the mould in his left hand, and with his right puts back a
spring, which keeps the matrix close up to the face of the mould, and then
with a small ladle adapted to the size of the work, he dips out of the pan over
the furnace a sufficient quantity of fluid metal to fill the mould, and at the
same instant that he turns the metal from out of the ladle into the mouth of it,
he throws up his hand, in which is held the mould, with a sudden jerk or shake,
and by this movement forces the melted metal down into the face of the matrix.
In this operation great expertness is necessary. After the letter is thus cast, he
relieves the spring, and takes the face of the type from the matrix, which is
done by pressing the thumb of the right hand against the top of the matrix;
he then picks out the type, and goes on with the casting. Thus, in the casting
of every single type, there are several distinct operations to be performed; yet,
owing to the admirable adaptation of the apparatus to the purpose, an expert
caster can, on an average, cast from six to seven thousand letters a day. When
the workman has cast as many types of the same letter as are required, he ex-
changes the matrix for one containing another letter, and proceeds as before.
The types, after being cast, are received by the “break-off boy,” who takes off
the break or rim of the letter;-this operation is performed with so much expe-
dition that some boys will break off from 5 to 6000 in an hour. From the
break-off boy the new types are put into the hands of a “rubber,” to have their
rag or beard removed, which is effected by rubbing them over a stone. A great
number of boys are employed in a type foundry besides those mentioned in the
various processes of the manufacture, — such as “kerners,” “setters up,”
“dressers,” &c., their operations being directed to the perfecting of the form
and finishing of the type, a circumstantial account of which our limited space
will not admit of. The metal of the type-founder consists of lead and anti-
mony fused together, the proportions of which are regulated by the size of the
type to be cast. The smallest sized types require the hardest metal, the alloy
for which is 25 of the regulus of antimony to 75 of lead, in 100 parts; in the
larger sizes the proportions are varied accordingly, down to 15 parts of
antimony to 85 of lead. The usual method of casting the larger kind of types,
is by cutting the letter through a plate of brass, and afterwards riveting to it a
back to form a matrix; these moulds are hung up, and the liquid metal
562 FOUND IN G.
simply poured into them; the very large letters are cast in open sand, in the
usual way of brass casting. The moulds and matrices of the type-founder are
extremely valuable, and are therefore secured every night in strong rooms of
Iron Or Stone.
By the common method of type-founding, which we have now briefly described,
only a single letter is cast at a time, and the operation has been nearly the same
for upwards of seventy years; a scheme was, however, set on foot by a Mr.
White, about seventeen years ago, to enable the founder to cast a great number
of letters at one time—thirty or more; but it was not carried into practice by
any of the founders. About the same time a Monsieur Didot, assisted by
Mr. Donkin the engineer, constructed a machine for a similar purpose, which
was also intended to perform all the operations of the work by the assistance of
a boy only.
The invention which we have now to describe is an improvement by Monsieur
Didot upon his former highly ingenious machine, now rendered capable of
casting 200 types at once, and to repeat the operation two or three times in a
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minute. A patent for this country was taken out by Mr. John Louis Pouchée,
who a few years ago established a type-foundry in Little Queen-street, Holborn,
where the machinery is at present in full and successful ºperation, The great
number of drawings which accompany the specification ºf this patent obliges us to
select such portions only as will best give a just idea of its nature and construc-
tion; and we have for the same reason thrown the side views intº perspective,























FRACTION. 563
which exhibits the machine entire, as at Fig. 1. Fig. 3 represents one side of
the mould separated into its component parts. Fig. 2 is a section of the several
bars composing both sides of the mould. Fig. 4 exhibits a plan of the same,
fitted into and encompassed by a frame of iron, a horizontal and perspective
view of which is given at Fig. 1. The same letters refer to the same parts in
each of the figures. a (Fig. 3) is a steel bar, with horizontal grooves, in which
are formed the bodies of the types; b b is the bar which holds the matrices c c,
each of which is arranged opposite to its respective groove in the bar a, to which
it is screwed fast; the bar d is then screwed down to the bar b, which holds the
matrices c c firmly in their places. The bar e is next laid upon the bar a, which
covers the grooves, and forms the upper sides of the square recesses, shown also
at e e, Fig. 4. f is the break-bar, and is placed in front of the bar a ; a series
of small nicks or openings are made in this bar, through which the fluid metal
passes into the grooves and matrices, where the body and letters of the type
are cast; the grooves are closed by the spaces between the nicks of the
break-bar coming against them, and forming the feet of the types. The bar
g is laid upon the break-bar as a cover to it, and the whole six bars thus com-
bined form one side, or one half, of a pair of moulds, shown in section, Fig. 3.
This section likewise exhibits the form of the apertures through which the fluid
metal has to pass into the grooves and matrices; h is a receptacle between the
moulds for the fluid metal, previous to its being forced into them, as we
shall presently describe. In preparing the moulds for casting, the several bars
composing them are connected together as before mentioned, and laid upon a
solid metallic bed upon the table k k, as shown at Fig. 4: the sides of the iron
frame l l, which turn upon joints, are then brought to bear sideways against the
moulds; the top piece m, which also turns upon a joint, is brought down
over the mould bars, which it firmly secures by bringing the looped part of the
swinging lever n, shown at Fig. 1, over the end of the top piece m, which is
effected by the aid of the hand lever p forcing the tongue o against the lower
end of the swinging lever, when the latch & falls and makes all fast. Thus
prepared, a sufficient quantity of the fluid metal is poured out of a ladle into
the receptacle between the moulds; a trigger at r is then pulled, when a string
connected to it draws back a bolt or catch s, which supports the long lever t,
and allows it to fall with the rammer q into the receptacle, which “drives with
considerable force the fluid metal from thence into the moulds and matrices.”
On each side of the rammer q is fixed “a guard or housing, to prevent the
liquid metal from being splashed over the operator.” In order to withdraw the
types from the moulds, the workman places his foot upon the step u, when the
compound lever v acts upon the pin w, under the leg z, and forces out the
rammer from between the moulds, which is then lifted up by the workman,
until it has passed the catch s, which supports it in the position shown in the
figure. The mould is now opened by throwing up the hasp a ; the swinging
lever n then releases the end of the top piece, and allows the frame to be
opened, and the moulds to be removed to a table, where the bars which compose
it are placed under cramps, and separated by means of wrenches: the types are
then removed, and undergo the operations of dressing, &c. as mentioned in the
early part of our subject.
FOUNT, or Font, among Printers, a set of types, sorted for use, that includes
running letters, large and small capitals, single letters, double letters,
points, lines, numerals, &c.; as a fount of english, pica, bourgeois, &c. A
common fount consists of 100,000 characters. See PRINTING and TYPE-
Foux DING.
FRACTION, in Arithmetic and Algebra, is a part or parts of something
considered as a unit or integer. Fractions are distinguished into vulgar fractions
and decimal fractions. Vulgar fractions consist of two parts or quantities
written one over the other, thus #, #, &c.; the quantity above the line is called
the numerator, and that below the line the denominator. Decimal fractions
are written with a dot to the left hand of the series, thus, 1, '02, '003, and may
be considered, and are read, as vulgar fractions, whose denominator is always
1, with as many cyphers annexed as there are figures in the decimal, and the
56 # FRICTION.
decimal will then be the numerator; thus, '1, '02, '003, are to be read as
i. ñº is
FlèANKINCENSE, or OL1BANUM, is a gum resin, the product of the Junipus
lycia of Linnaeus, brought from Turkey and the East Indies, usually in drops
or tears. The best sort is of a yellowish white colour, solid, hard, and brittle.
When chewed it impresses an unpleasant bitter taste; laid on burning coals
it yields an agreeable odour, and is for this reason much used by the Catholics,
the Jews, and various idolatrous nations, in their religious ceremonies, the
powerful perfume having a tendency to prevent the communication of infection
amongst a dirty people, and of moderating the disgust created by the slaughter
of the victims of the sacrifices.
FREEZING. See CoNGELATION, FRosT, and C11EMISTRY.
FRICTION, in Mechanics, the rubbing of the parts of engines or machines
against each other, by which means a great part of their effect is destroyed. A
body upon a horizontal plane should be capable of being moved by the smallest
application of force; but this is not the case, and the principal causes which
render a greater or less application of force necessary are, first, the roughness
of the contiguous surfaces; secondly, the irregularity of figure, which arises
either from imperfect workmanship or the penetration of one body by another;
thirdly, an adhesion or attraction, which is more or less powerful according to
the nature of the bodies in question; and fourthly, the interposition of extra-
neous bodies, as dust, moisture, &c. Innumerable experiments have been made
to determine the amount of friction or obstruction which is produced in parti-
cular circumstances; but the results of apparently similar experiments which
have been made by different experimenters do not agree, nor is it likely they
should, since the least difference of smoothness or polish, or of hardness, or,
in short, of any of the concurring circumstances, produces a different result:
hence no certain and determinate rules can be laid down on the subject of
friction. Mr. Vince, who has done much on this subject, infers, first, that
friction is a uniformly retarding force in hard bodies, not subject to alteration
by the velocity except when the body is covered with cloth, woollen, &c., and
in this case the friction increases slightly with the velocity; secondly, friction
increases in a rather less ratio than the weight of bodies; the rate of increase,
however, is various in different bodies, nor is it sufficiently determined for
any one body what proportion the increase of friction bears to the increase of
weight. The smallest surface, at least up to a certain point, has the least
friction, the weight being the same; but the ratio of friction to the surface is
not yet accurately known. The friction of mechanical engines not only
diminishes the effect, or, which is the same thing, occasions a loss of power,
but is attended with the corrosion and wear of the principal parts of the
machine, besides producing a considerable degree of heat, and even actual fire;
it is therefore of great importance in mechanics to contrive means capable of
diminishing, if not quite removing, the effect of friction.
The methods of obtaining the important object of diminishing friction are of
two sorts, viz. either by the interposition of unctuous or oily substances between
the contiguous moving parts, or by particular mechanical arrangements.
Olive oil is the best and perhaps the only substance that can be used in delicate
work, as clocks and watches, when metal works against metal ; but in large
works the oil is liable to drain off unless some method be adopted to confine it.
The best contrivance with which we are acquainted, for preventing the waste
of oil, and for keeping gudgeons or axes properly supplied with it, is Barton's
Patent Lubricator, a section of which is shown in the accompanying engraving,
with the manner of applying it to the shafts of mill work. a shows a section
of a metallic vessel filled with oil, and closed by a lid to prevent the admission
of dust or other adventitious matter; b is a small tube rising to nearly the top
of the vessel, and with the lower part extending an inch or two below it, and
inserted into an aperture made through the plummer block, directly over the
shaft c, shown also in section ; through this tube a few threads of woollen yarn
are drawn, which reach to the bottom of the vessel, and conduct the oil by
capillary attraction, as a syphon, in minute but regular quantities to the shaft
FRICTION. * * * 565
or gudgeon; the whole of the oil in the vessel is thus carried over, entirely free
from dust or other impurities, and in the precise quantity required, which is easily
regulated by the number of threads. It must be obvious that the economy of
T
—r ºr-
this contrivance is very considerable; that machinery, where it is applied, wilí
run with less friction, last longer, and require less power. Since the above
cut was executed, Mr. Barton has greatly improved these lubricators, and
materially extended their utility. From some experiments which have been
made, it appears that when the strain is very great the solid unguents appear
to be more effectual in diminishing friction than oils, and in this case tallow
or swine's grease is generally employed. The celebrated “Anti-Attrition Com-
position” is simply a mixture of hog's lard and plumbago, in the proportion
of four parts of the former to one of the latter. In launching ships the
“ ways” are smeared with soft soap. The mechanical contrivances for the
diminution of friction consist either in avoiding the contact of such bodies as
produce much friction, or by substituting a rolling for a sliding motion, as far
as it may be practicable. As an instance of the first method we may notice
that in mill work, the wooden axes of large wheels terminate in iron gudgeons,
turning generally in brass bearings, which produces less friction than wood
upon wood; and as the iron gudgeon can be made of smaller diameter than
wooden ones of the same strength, the friction is also diminished from that
cause in nearly the same ratio. The conversion of a sliding motion into a
rolling motion is effected by interposing cylindrical bodies between the moving
parts of machines, which, according to their size and arrangement, are denomi-
nated rollers, wheels, and (although improperly) friction rollers. In order to
understand the nature of rollers, and the advantages attending their use, it
must be considered that when one body is dragged over the surface of another,
the inequalities of the surfaces of both bodies meet and oppose each other,
which is the principal cause of friction or obstruction; but when one body,
such as a cask, a cylinder, or a ball, is rolled upon another body, the surface
of the roller does not rub upon the latter, but its parts are successively
applied to or laid upon it, and are afterwards lifted up from it; therefore,
in rolling, the principal cause of friction is avoided, and other advantages also

4 C
566 FUEH,.
obtained: thus, in mounting a carriage upon wheels, instead of placing it
upon skids or a sledge, the only friction arising from the sliding of one part
over another is that which takes place between the axle and the box in which
it works. The diminution of friction from this cause will be in the proportion
of the diameter of the wheel to that of the axle, and it is further diminished
by the friction being that of metal sliding upon metal, which offers much less
resistance than the best made road could be brought to do, and also that the
friction may be further reduced by means of lubricating substances. When the
sliding motion in machinery is not in a rectilinear direction, but arises from the
revolution of axes in their bearings, a great part of it may be converted into a
rolling motion by supporting the axes upon the peripheries of four wheels instead
of the usual fixed bearings; an instance of this is seen in the elegant machine
invented by Mr. Atwood for illustrating the laws by which the descent of falling
bodies is regulated. But although friction detracts from the effect of machines,
and it is therefore generally an object to reduce it to the utmost, yet the action
of some parts of machinery depends upon friction, as in the case of the brake
of a crane or the drag of a coach. For light machinery, also, wheels are some-
times made to turn by contact, by simply covering their periphery with buff
leather, the resistance of the work not being sufficient to overcome the friction
between the two surfaces.
FRIT. The matter or ingredients of which glass is made, after they have
been calcined in a furnace. These ingredients are chiefly soda and flint, or
silicious sand.
FRIZING OF CLOTH. . A term applied to the forming the nap of
woollen cloth into a number of little hard burs or prominences covering almost
the whole of the ground. It is commonly performed by a machine or mill
worked by water or horses; the structure is as follows:—The principal parts
are the frizer, the frizing table, and the drawer or beam ; the two first are
two equal planks or boards, each about ten feet long and fifteen inches broad,
differing only in this, that the frizing table is covered with a coarse kind of
woollen stuff, with a rough sturdy nap, and the frizer is incrustated with a kind
of cement, composed of glue, gum arabic, and a yellow sand, with a little aqua
vitae, or urine. The beam or drawer, thus called because it draws the stuff
from between the frizing table and the frizer, is a wooden table, beset all over
with little, fine, short points or ends of wire, like those of cards used in carding
of wool. The cloth, being stretched along the frizing table with that side upper-
most which is to be frized, is drawn slowly over the table by the beam or drawer,
whilst the frizer, which is suspended at such a distance from the table as merely
to allow the cloth to pass between the two surfaces, and which has a very slow
semicircular motion, meeting the long hairs or maps of the cloth, twists or rolls
them into little nobs or burs; the workman supplying and stretching the cloth
at one end of the table as fast as it is drawn forward by the drawer at the
other end.
FROST. Such a state of the atmosphere as causes the congelation or
freezing of water or other fluids into ice. In the more northern parts of the
world even solid bodies are affected by frost, though this is only or chiefly in
consequence of the moisture they contain, which being frozen into ice, and so
expanding, as water is known to do when frozen, it bursts and rends any thing
in which it is contained, as plants, trees, stones, and large rocks. Many fluids
expand by frost, as water, which expands about one tenth part, for which reason
ice floats in water; but others again contract, as quicksilver, and thence frozen
quicksilver sinks in the fluid metal.
FRUSTRUM, in Geometry, is the part of a solid next the base left by
cutting off the top or segment by a plane parallel to the base, as the frustrum
of a cone, a pyramid, a conoid, or of a sphere, which is any part comprehended
between two parallel circular sections; and the middle frustrum of a sphere is
that, whose ends are equal circles.
FUEL. Those substances which receive and retain fire until they are wholly
or partially consumed. Dr. Black divided fuel into five classes. The first com
prehends the fluid inflammable bodies; the second, peat or turf; the third,
l’UE L. 567
charcoal of wood; the fourth, pit coal charred; and the fifth, wood or pit coal
in a crude state, and capable of yielding a copious and bright flame. The fluid
inflammables are considered as distinct from the solid on this account—that
they are capable of burning upon a wick, and become in this way the most
manageable sources of heat, though, on account of their price, they are never
employed for producing it in great quantities, and are only used when a gentle
or small degree of heat is sufficient. The species which belong to this class
are alcohol and the different oils. The first of these, alcohol, when pure and
free of water, is as convenient and manageable a fuel for producing moderate
heats as can be desired; its flame is perfectly clean and free from any kind of
soot; it can easily be made to burn slower or faster, and to produce less or more
heat, by changing the size or number of wicks upon which it burns;––for
as long as these are fed with spirit in a proper manner, they continue to yield
flame of precisely the same strength. The cotton, or other materials of which
the wick is composed, is not scorched or consumed in the least, because the
spirit with which it is constantly soaked is incapable of becoming hotter than
1740 Fahr. ; it is only the vapour which arises from it that is hotter, and this,
too, in the parts most remote from the wick, and where only the combustion is
going on, in consequence of communication and contact with the air. At the
same time, as the alcohol is totally volatile it does not leave any fixed matter,
which, by being accumulated on the wick, might render it foul and fill up its
pores; the wick, therefore, continues to imbibe the spirit as freely, after some
time, as it did at the first. These are the qualities of alcohol as a fuel: but
these qualities belong only to a spirit that is very pure. If it be weak, and
contain water, the water does not evaporate so fast from the wick as the more
spirituous part, and the wick becomes, after some time, so much soaked with
water that it does not imbibe the spirit properly : the flame becomes much
weaker, or is altogether extinguished. When alcohol is used as a fuel, there-
fore, it ought to be made as strong or as free from water as possible. Oils,
though capable of burning in a similar manner to alcohol, are not so conve-
nient in many respects; the soot which they emit accumulates at the bottom of
the vessel exposed to it, and checks the transmission of heat. By employing
numerous very small wicks, or the argand burners, we may chiefly prevent the
formation and deposit of soot ; but the wicks become scorched or charred, and
are soon rendered incapable of absorbing the oil so fast as before. Attempts
have been made to obviate this difficulty by making wicks of incombustible
matter, as asbestos or wire; nevertheless, as the oil does not totally evaporate,
a small quantity of gross carbonaceous matter fixes itself to the wicks which,
by degrees, absorb less and less of the fluid, until they become quite useless.
The second class of fuel mentioned, peat or turf, is so spongy, that, compared
with the more solid fuels, it is unfit to be employed for producing strong heats.
It is too bulky for this; we cannot put into a furnace at a time a quantity
that corresponds with the quick consumption that must necessarily go on when
the heat is violent. There is, no doubt, a great difference in this respect among
different kinds of peat, but this is the general character of it; however, when
we desire to produce and keep up by means of cheap fuel an extremely mild
uniform heat, we can hardly use any thing better than peat; but it is best to have
it previously charred or burnt to a black coal. When prepared in this manner
it is capable of being made to burn more slowly and gently, or will bear, without
being extinguished altogether, a greater diminution of the quantity of air with
which it is supplied than any other of the solid fuels. According to Clement
and Desormes peat affords only about one-fifth of the heat that is given out by
an equal weight of charcoal. Mr. Tredgold states, that the weight of a cubic
foot varies from 44 to 70 pounds, and that the dense varieties afford about 40
per cent. of charcoal; the other varieties nearly in proportion to their density.
The third class mentioned, the charcoal of wood, is capable of affording an
intense heat. Mr. Dalton, by heating water, obtained a result equivalent to
melting 40 lbs. of ice with 1 lb. of charcoal. Dr. Crawford's experiments give
69 lbs. of ice melted by 1 lb. of charcoal. Lavoisier, Clement, and Desormes,
about 95 lbs. ; and Hassenfratz, 92 lbs. Mr. Tredgold considers 47 lbs, of ice
568 FUEL:
melted to be the real average effect of 1 lb. of charcoal: a cubic foot weighs
about 15 lbs. -
The fourth mentioned class of fuel, pit coal charred or coke, , possesses
similar properties to wood charcoal, although it is a much stronger fuel,--that
is, it contains the combustible matter in a more condensed form; it is, there-
fore, consumed much more slowly, and is better adapted for long-continued
intense heats. It has, however, a defect, from which wood charcoal is free; it
leaves dense ashes in the grate, which in time collect in such quantity as to
obstruct the passage of the air; and when the heat is intense, these ashes
vitrify into a tenacious substance, which clogs the furnace. It is preferable to
wood coal for melting metals, as affording a greater quantity of heat before it
is consumed, and at a less expense.
The fifth class of fuel, according to Dr. Black, is wood and crude coal; these
differ from their charcoals in affording copious and bright flames when plenty
of air is admitted to them. If but little air be admitted sooty vapours are
given out without flame, and with greatly diminished heat. Wood and candle
coal do, however, differ from each other so much, as respects their useful pro-
perties in manufacturing operations, that we deem it necessary here to drop the
generalization of Dr. Black, and consider wood and coal, and the varieties of
each, separately. First, as respects—
Wood; its effect in producing heat depends greatly on its state of dryness.
Several experiments made by Count Rumford show the effect of dry wood to
be much greater than that of unseasoned; the latter containing about one-third
of its weight of water. The kind of wood is also a cause of some difference;
lime-tree wood was found, by Count Rumford, to give out most heat in burn-
ing. With 1 lb. of dry pine-wood, the Count caused 20.10 lbs. of ice-cold
water to boil. The same weight of dry beech made only 14.33 lbs. of ice-cold
water to boil. A cubic foot of dry beech weighs about 49 lbs. By the experi-
ments of Fossombroni, wood was found capable, by its combustion, to evapo-
rate twice its weight of water, or to prepare two-thirds of its weight of salt.
Rumford made the effect about one-third more than Fossombroni, owing, pos-
sibly, to superior management in the former. By an experiment made at the
Opera House, in Paris, 160 lbs. of wood were found to be equal in effect to
58 lbs. of coke. -
As respects coal, there is a considerable difference in the effects of the several
varieties. The caking or binding coal with which London is supplied from the
great coal fields in Northumberland and Durham, under the general name of
Newcastle coal, is much esteemed, from its affording a great heat, and burning
with a lively flame; but those of Wall's End are regarded as superior to the
latter for domestic use, as they burn with a whiter and more brilliant flame, and
do not cake so hard in the grate. The Tanfield Moor coals are preferred for
forges and furnaces, as they burn slowly, and afford a strong and long continued
heat. From the experiments of Mr. Watt, it appears that a bushel of New-
castle coal, which weighs about 84 lbs. is competent to convert from 8 to 12
cubic feet of water into steam, from the mean temperature of the atmosphere;
and that a bushel of Swansea coal will produce the same effect. Dr. Black
states, 7.91 lbs. of the best Newcastle coals will convert one cubic foot of water
into steam capable of supporting the mean pressure of the atmosphere ; and
this statement appears perfectly to accord with the more extended experiments
of Watt. Smeaton makes it require 11.4 lbs. of coal to produce the same
result in steam ; but Smeaton has omitted to state the kind of coal. If he
employed the Staffordshire coal, there is no discrepancy, as will appear from
the table of Mr. Tredgold's experiments and calculations, which we shall subse-
quently insert in this article. Mr. Tredgold found, that after the brickwork, &c.
of the boiler of a steam-engine was warmed, a little less than 1 lb. of Wall's End
coals would make a cubic foot of water boil, from the mean temperature of
529. To produce the same effect with inferior coals a stronger draft and more
time and attention are necessary. Splint coal, or hard coal, called by Kirwan
slaty cannel coal, is regarded as equally valuable for many purposes as the
Newcastle caking coal. It does not produce so much flame nor so much
FUEL. 569
smoke; it does not kindle so quickly, nor does it agglutinate, like caking coal.
A large body of splint coal makes a strong and lasting fire. Cherry coal, or
soft coal, readily catches fire, and burns with a clear yellow flame, giving out
much heat, and the flame continues till nearly the whole coal is consumed. It
burns away more rapidly than either caking or splint coal, and leaves a white
ash; it is easily distinguished from caking coal by its not melting or becoming
soft when heated; it makes a more agreeable fire, and does not require to be
stirred. It requires care and management in an open grate, even to burn the
small fragments which are made in breaking up the pieces to a fit size for the
fire : hence the small coals are often mixed with clay, and made into balls.
When these balls are dry, Mr. Gray says, they make an excellent addition to
the fuel for an open fire, producing a very durable heat. Mr. Watt calculated
that 112 lbs. of these coals produced the same effect in raising steam as 84 lbs.
of the Newcastle coal.
The following table, by Mr. Tredgold, shows the comparative and real effect
of the principal varieties of solid fuel in converting water into steam.

Fraction of a pound that | Pounds of fuel that
Kind of fuel. will heat one cubic foot | will convert one
of water one degree of cubic foot of water
Fahrenheit’s scale. into Steam.
Newcastle, or caking coal 0.0075 8.40
Splint coal . . . . . 0.0075 8.40
Staffordshire cherry coal. 0.01 ()0 } | .20
Wood (dry pine) . . . . 0.0172 - 19.25
, (dry beech) . . 0.0242 27.00
, (dry oak) . . . 0.0265 30.00
Peat of good quality . . . 0.0475 - 53.60
Charcoal . . . . . . 0.0095 10.60
Coke . . . . . . . . 0.0069 | 7.70
Charred peat . . . . 0.0205 23.00
Mr. S. F. Gray is of opinion that fire-balls, of the size of goose eggs, composed
of coal and charcoal in powder, mixed with a due proportion of wet clay, and
well dried, would make a much more cleanly and in all respects a pleasanter fire,
than can be made with crude coals, and not more expensive. He states, that in
Flanders and Germany the practice of making equal weights of clay and coals
together, and forming them into cakes, is common, and that the labour of the
preparation is amply repaid by the improvement of the fuel, the coals thus mixed
burning much longer, and giving more heat, than when they are burnt in their
crude state; that although clay is an incombustible body, the fact is certain
that coals so mixed afford more heat. For the purpose of lighting a fire speedily,
Mr. Gray recommends the formation of “kindling balls,” composed of equal
parts of coal, charcoal, and clay, the two former reduced to a fine powder, well
mixed and kneaded with clay moistened with water, and then formed into
balls of the size of hens' eggs, and thoroughly dried, which, he says, may be used
with great advantage, instead of wood. These kindling balls, he further observes,
may be made so inflammable as to take fire in an instant, and with the smallest
spark, by dipping them in a solution of nitre, and then drying them again ; if
made of pure charcoal mixed with a solution of nitre, they would be still more
inflammable. In situations where coals are scarce or dear we think that the
mixtures recommended by Mr. Gray might be found convenient and economical;
but when it is considered that the average price of coals in England is not more
than a shilling for a hundred weight, we can hardly conceive it possible that
the same weight of fire-balls, of the size of hens' eggs, could be manufactured
for the sum mentioned. It would appear, from Mr. Gray's remarks, that he
was not aware that several patents had previously been taken out for the very
objects mentioned by that gentleman; and although the advantages of them
may not be very apparent in most situations, there are doubtless many localities
where it may be otherwise; for the latter reason we shall, therefore, insert a
57() FUMIGATION.
§
brief notice of some of them. Mr. Sunderland's patent dated 1825, is for a
fuel, in which gas-tar, clay, and refuse woody matter, are combined in various
proportions, according to the degree of inflammability required. One part of
gas-tar, one of clay, and two parts of any convenient woody matter, such as
saw-dust, tanners' spent bark, dyers' refuse wood, or peat, burn extremely well.
If equal parts of the tar, clay, and saw-dust be employed, they make a com-
position which burns vividly and with a brilliant flame. The materials are, of
course, to be thoroughly mixed, made up into lumps, and dried either artificially
or in the open air, preparatory to their being used as fuel. Messrs. Christie
and Harper's patent, dated 1824, was for various mixtures of culm and stone
coal (or anthracite) with bituminous or caking coal, depending upon the nature
of the heat required; for the boiler furnaces of steam engines, where the bars
are half an inch apart, the patentees state that one-fourth of the bituminous
coal answers well for invigorating the other three-fourths. In 1800 Mr. Peter
Devey had a patent for an improved artificial fuel, and the same gentleman, in
1821, had another patent for fuel balls, the particulars of which will be found
in the specifications of their patents in the Inrolment offices in Chancery.
FULCRUM, in Mechanics, the prop or support upon which a lever turns.
FULLER'S EARTH. A soft, greyish brown, dense marl. When dry it is
of a greyish ash-coloured brown, in all degrees, from very pale to almost black,
and it has generally something of a greenish cast; it is of a compact texture,
smooth to the touch, and does not stain the fingers. Thrown into water it
makes no ebullition or hissing, but swells gradually in bulk, and falls into a fine
soft powder. Fuller's earth is of great use in scouring cloths, stuffs, &c., imbibing
all the grease and oil used in preparing and manufacturing the wool; but owing
to the almost general use of soap for these purposes, it is not now in such
request in this country as formerly. In England it is found chiefly in Hamp-
shire, Bedfordshire, and Surrey; it consists of
Silex . . . . . . . . . . . . . . . 51.8
Alumine . . . . . . . . . . . . . . 25.0
Lime . . . . . . . . . . . . . . , 3.3
Magnesia . . . . . . . . . . . . . . 0.7
Oxide of Iron . . . . . . . . . . . . 3.7
Water . . . . . . . . . . . . . . 15.5
FULLING. A process by which woollen cloths are divested of the oil they
imbibe by the operation of carding, and the texture at the same time rendered
much closer, firmer, and stronger. This process, also called milling, is per
formed by a mill, thence called a fulling mill, the machinery of which consists
of a number of wooden stampers or beetles, working in a large trough by
means of cams or wipers on the shaft of a water wheel. The cloths are laid
in the trough, and a quantity of warm water, in which is put a portion of fuller's
earth or soap, being poured upon it, it is subjected to the action of the stampers,
the repeated blows of which cause the fibres to felt and combine more closely
together. After a time it is taken out, and the grease and filth wrung therefrom,
and again returned to the fulling mill, from which it is occasionally taken to be
stretched, and to undo the plaits it has acquired in the trough. When it is
sufficiently milled and brought to the quality and thickness desired, it is scoured
in the trough in clear water until perfectly clean, after which it is hung upon
tenter-hooks to dry.
FULMINATING POWDERS. A variety of chemical combinations,
which explode, by the application of certain degrees of heat, with instantaneous
combustion and prodigious noise. See DETon ATING Powders.
FUMIGATION. A process for destroying contagious miasmata or effluvia,
by the fumes of various substances. The most efficacious substance for this
purpose is chlorine, which may be readily applied in the state of gas by placing
in the apartment to be fumigated an earthen pan, containing sea salt and black
oxide of manganese, and pouring dilute oil of vitriol upon the mixture; but a
FURN ACES 57.1
solution of chloride of lime is generally preferred. Next to chlorine in efficiency
is the vapour of nitric acid; and, lastly, of muriatic acid ; but the fumes of
heated vinegar, burning sulphur, or exploded gunpowder, deserve little confidence.
FUNNEL. A conical or bell-mouthed instrument with a narrow tube, for
facilitating the transferring of liquids or small substances from one vessel to
another. Any pipe or passage is sometimes called by this name, in particular
the small shaft or tube of a flue.
FUR, in Commerce, signifies the skins of several species of animals, dressed
in alum, with the hair on, and used for the purposes of dress. The kinds mostly
made use of are those of the ermine, sable, beaver, hare, rabbit, &c. The fur,
properly so called, of various amphibious animals, as the seal and beaver, is
protected by a coating of long coarse hair; this hair requires to be removed
prior to the short fur being sheared off for the purpose of covering hats. This
is generally effected by hand, for which purpose women and children are em-
ployed; but a patent has recently been obtained by Mr. A. Bell for a machine
for performing the operation, the mechanical arrangements of which appear
to be simple and effective. The skin passes round a projecting bed, and is
advanced by machinery arranged for that purpose, the tension of the skin being
duly maintained by weights. In front of the projecting bed are two cylinders
of greater length than the width of the skins, and four or five inches in diameter.
Over the circumference of each of these cylinders, but in contrary directions,
is wound, in a spiral line, a projecting rib; each of these ribs making only one
revolution of the cylinder in spirally traversing its entire length. These cylin-
ders are driven by means of a rigger on the axis of the lower one, and are
placed so near to each other as to occasion the ribs to come in contact and to
press whatever hair or fur comes between them. As the skin is drawn forward
over the edge of the projecting bed the long hairs stand nearly at right angles
to the ribs on the cylinders, which, in their revolution, forcibly seize the hairs,
and extract the same. In order that the pressure of the ribs may be somewhat
elastic, and take better hold of the hairs, they are covered with leather.
FUR LONG. A measure of length, equal to the eighth part of a mile, or forty
voles.
} FURN ACE. A vessel or apparatus, wherein fuel is burnt in chemical, manu-
facturing, and culinary operations. Furnaces are as various, and even more so,
than the particular objects for which they are designed ; to accomplish these so
that they shall perform their offices in the most economical and convenient
manner, is the proper study of those who have to construct or employ them.
The proper choice of materials, adapted to the degree of heat and other circum-
stances, is also of the greatest importance; indeed, the resulting products of
furnaces greatly, and often wholly, depend upon the combined application of
chemical knowledge, manufacturing experience, and inventive skill. The fol-
lowing appear to be the essential qualifications of a good furnace : first, to be
able to concentrate the heat, and direct it as much as possible to the sub.
stances to be acted upon ; second, to prevent the dissipation of the heat after
it is produced; third, to obtain the greatest quantity of heat from a given
quantity of fuel; fourth, to be able to regulate at pleasure the necessary
degree of heat, and have it wholly at the operator's management. Under the
articles BoILER, IRoN, AIR, Foun DRY, and various others that occur in this
work, numerous practical examples are given of the construction of furnaces;
it will therefore be our business, under the present head, to supply the defi-
ciencies that are left on the subject, which we shall premise by some observations
on the nature and proper construction of furnaces in general. In the construc-
tion of furnaces for boilers every thing should be combined that has a tendency
to add to the effect of the fuel, and to avoid that which is calculated to diminish
its effect; but without a knowledge of the nature of burning, we should be
like seamen traversing the ocean without a compass. When a portion of fuel is
ignited in a close fire-place it must be supplied with air to enable it to burn :
and the fuel itself in the process of burning is partly converted into gaseous
matter, which escapes up the chimney with a portion of the air supplied to the
fire; but the greater part of the air so supplied ought (as Mr. Tredgold observes)
572 FURN ACES.
to be changed in the process, by its oxygen uniting with the carbon, and other
combustible parts of the fuel, forming carbonic acid gas, vapour, &c. Now, in
order that perfect combustion, or burning of the fuel, may take place, the air
should have free access to every part of the fuel, which is heated sufficiently
to burn; as fuel must be heated in a certain degree, otherwise its elements
will not combine with the oxygen of the air. And we see clearly the advan-
tages of a regular supply of fuel: this advantage is greater in proportion to the
quantity of hydrogen contained in the same; for if a large body of such fuel be
at once put upon the fire, much of the hydrogen will escape in a gaseous state
unconsumed, carrying off with it a very considerable portion of heat; whereas
if the fuel be thinly scattered over the surface of the fore part of the fire the
hydrogen would most likely be consumed in passing over the red hot embers in
the after part of the fire, and the product go off in steam ; and that the latent
heat of such steam may not be lost, it will be desirable to have a horizontal flue
of metal for the smoke to pass along after it has left the boiler, when the steam
can be condensed, and the heat applied to warm water for the boiler or other
useful purposes. But to succeed in consuming the combustible gases, it is
necessary that they should mix with the air that has become hot by passing (as
expressed by Mr. Watt, in the specification of his patent in 1785,) “through,
over, or among, fuel that has ceased to smoke,” or by being drawn through small
flues or channels in the brickwork round the fire, in such a manner as to
be heated before it mixes with the gas to be consumed; but unless hydrogen,
or some of its combinations, are constantly passing off, the introduction of a
stream of air into the fire-place will only take away the heat from the boiler;
and therefore in a slow fire, consisting chiefly of carbon, it will do more harm
than good; while in a quick fire of cherry coal, or cannel coal, in which
hydrogen is abundant, it must be a great advantage, and particularly when
the fire is regularly supplied with fuel. The quality of the air to supply the
fire, Mr. Tredgold remarks, is worthy of being considered, although any
dirty wet hole is usually esteemed good enough for the fire place. Now
the air ought to be dry, for air charged with moisture is improper, and only
takes away heat; but where there is a very low chimney, and consequently
an imperfect draft, some water in the ash-pit will increase the draft, by
being converted into steam by the heat of the ashes, the mixture of the steam
rendering the smoke much lighter than common air. The air should be cool
when it enters the ash-pit, that it may pass with greater velocity through
the fire, and the fire-place shed should be dry, in order that the apparatus
may be durable, and be kept in order with little attention. The opening to
admit air to the fire should be sufficiently large for producing the greatest
quantity of steam that can be required, but not larger, and it should be
constructed so as to increase in size as it approaches the fire. The area of
the spaces between the bars should clearly be much greater than the area of
the place that admits air to the fire. The fire should be made immediately
under the boiler or other vessel to be heated, that its full effect may be exerted
upon the bottom ; and after quitting the fire, the mixture of flame and smoke
should pass through a wide and shallow aperture, called the throat;-wide, that
it may spread under the greatest surface of the boiler; and shallow, that it may
pass through with considerable velocity, and consequently be impelled against
the bottom of the boiler. In making the flue circulate, according to the usual
mode, round the sides of a long boiler, the heat never extends far enough to
render it effectual throughout its length, and the action being oblique the
advantage gained is very trifling; for the same reasons, the making of a flue
to return through the boiler offers no advantage that compensates for its com
plexity of construction, since the heat may as well be confined to act upon the
bottom, and have less depth of water. The depth of fuel to be on fire at the
same time should be sufficient to ignite the fresh fuel, without impairing its
action on the boiler in a sensible degree. From the observations and experi-
ments made by Mr. Tredgold to determine this point, it appears that the depth
of burning fuel should be about three or four times the depth of what is added
at a time in feeding the furnace; that is, four times when you feed frequently,
FURN ACES. 573
and three times when you feed seldom ; and according to the nature of the
fuel, there will be greater or less space wanted between the bars and the
boilers. In the construction of furnaces, the slowest conductors of heat should
be used; some metal work is absolutely necessary—that is, simply the bars and
a frame at the mouth, where the fuel is put in, with or without a door; in the
latter case, the space is to be filled with fuel. The rest of the brickwork should
be built with hard well burnt bricks; and in order to confine the heat to the
boiler, it will be proper to leave cavities in the brickwork; and, with the excep-
tion of the necessary ties, to form a double wall, with a hollow space between,
keeping the maxim of Morveau always in view—to insulate the fire-place from
all bodies that are rapid conductors of heat. Between the fire door and the bars
there should be a dead space; on this the fresh coals are laid, previous to their
being pushed forward on the grate, which should not be done until they have
given out their gas over the brightly ignited fuel on the bars. . This dead space
is usually covered with an iron plate, called a dead plate, but it is preferable to
floor it with fire tiles, as the latter are less liable to affect the fittings of the door
and frame. The bars are of course proportioned to the size of the furnace;
they are usually from 13 to 3 inches in depth, and the thickness varying from
# to 14 inch ; the length seldom exceeds three feet; and where a more extended
grate is required, they are generally laid in separate lengths upon transverse
bearing bars, which receive both ends. The spaces between the bars are from
# to 3 an inch. The whole area of the grating should be about one-fourth the
area of the bottom surface of the vessel to be heated; each foot of such grating is
adapted, according to Mr. Tredgold's calculations, to burn one-eighth of a bushel
of coal per hour. The same area will answer for either a slow or a quick fire,
but in a slow fire a greater depth of fuel is necessary; and also for equal bulks
of any other kind of fuel, the same area will apply as for coals; but it will be
obvious from this rule that the areas to produce equal quantities of steam
will be inversely as the power of the fuel. The damper is best situated at the
opening into the flue; it should be supported in its slide by a counterbalance
weight, and its action be rendered easy and certain. . The door should be made
to shut as close as possible; but there is a difficulty in keeping it so, when
exposed much to the action of the fire; they are best defended by making
them double, with a hollow space for air between them. Mr. Atkinson's mode
of constructing them is good; he rivets on the inside a hollow cast-iron box,
which just fits the doorway; the depth of the sides of the box so strengthens
the door as to prevent its warping, while the hollow space of confined air
prevents the escape of heat. A sliding door, balanced by a weight, in the
manner of a sash window, has many advantages; it is more easily opened and
shut; is out of the way when open, and shuts close : when any thing is to be
done at the fire, a smaller opening suffices.
Delasme's Furnace.—The invention of a mode of constructing furnaces cal-
culated to burn all the smoke given out by the fuel, is usually attributed to our
celebrated countryman, Mr. James Watt; but it appears from the volume of the
Academy of Sciences, at Paris, for 1699, that some successful experiments
were made by M. de la Hire, which had reference to an invention of many
years previous date, by Delasme, a French engineer. The latter, we are told,
exhibited his furnace for consuming its own smoke at the fair of St. Germain,
in the year 1685. The fire-place of Delasme consisted of a long tube,
bent into the form of a syphon, and inverted, the longest leg of which formed a
chimney, and the shortest the furnace. The fuel was deposited on a grating
near the top of the shortest leg, being supplied from above. Soon after the
ignition of the fuel the heat was communicated to the longest leg or chimney,
and by that means a current of air was caused to pass downward through the
fuel, and under the grate, where the smoke was consumed.
Watt's Patent.—The earliest application in this country of apparatus for
consuming the dense smoke of furnaces, that we are acquainted with, is the
invention of Mr. Watt, in 1785, before alluded to. It is thus described by him in
his specification : “My newly improved methods of constructing furnaces or
fire-places, consist in causing the smoke or flame of the fresh fuel, in its way
4 D
574 FURN ACES.
to the flues or chimney, to pass, together with a current of fresh air, through,
over, or among fuel which has already ceased to smoke, or which is converted
into coke, charcoal, or cinders, and which is intensely hot; by which means
the smoke and grosser parts of the flame, by coming into close contact with, or
by being brought near unto, the said intensely hot fuel, and by being mixed
with the current of fresh or unburned air, are consumed or converted into heat,
or into pure flame, free from smoke. I put this in practice, first, by stopping
up every avenue or passage to the chimney or flues, except such as are left in
the interstices of the fuel, by placing the fresh fuel above or nearer to the
external air than that which is already converted into coke or charcoal; and by
constructing the fire-places in such manner that the flame and the air which
animates the fire must pass downwards, or laterally, or horizontally, through
the burning fuel, and pass from the lower part or internal end or side of the
fire-place to the flues or chimney.” Mr. Watt then gives an example and
a description of the application of this principle in his specification, which we
do not here insert, as there have been some improved arrangements introduced
which we shall have occasion to notice elsewhere. The specification next
proceeds to state as follows: “In some cases, after the flame has passed through
the burning fuel, I cause it to pass through a very hot funnel, flue or oven,
before it comes to the bottom of the boiler, or to the part of the furnace where
it is proposed to melt metal, or perform any other office, by which means the
smoke is more effectually consumed. In other cases, I cause the flame to pass
immediately from the fire-place into the space under a boiler, or into the bed
of a melting or other furnace.” We annex the inventor's example of this
arrangement of the furnace, as it is simpler than the former, and equally effec-
tive. a a represents a reverberatory furnace, for melting iron, of which b is the
YS's |, \"
(*~~ {{
Frºm a
flue; e is the ash-pit, and f a door thereto ; g is a hopper-like receptacle for
the fresh fuel, which gradually sinks down as it is consumed beneath ;-about
the middle of this mass of fuel it is intensely hot, as it consists of coals and
coke that have ceased to smoke. At i is an opening or openings to admit fresh
air, and regulate the fire. At the opposite end of the furnace is another door,
to be used either for charging the furnace or stopping its operation, which is
effected by the counter current produced by the opening of the door. The fire
is first lighted upon the brick arch l, and when well ignited, more fuel is
gradually added, until it is filled up to g, care being taken to leave prope.
interstices for the air to pass, either among the fuel, or between the fuel and
the front wall; and as much air is admitted at the opening i as can be done,
without causing the smoke to ascend perpendicularly from 9, which it would
do if too much be so admitted. “Occasionally the opening at g is closed with














FURN ACES. 575
a cºver, to cause the air to enter wholly or partially at i.” By this addition, it
will be noticed, Mr. Watt first applied the closed hopper, now so much used
in the feeding of furnaces. -
The following figure exhibits another admirable contrivance of Mr. Watt's,
which many succeeding inventors have claimed as their own, as well as that plan
Me
tº sº.
already described. Mr. Watt observes,—“In some cases I place the fresh fuel on
a grate, as usual, as at a, and beyond that grate, at or near the place where the
flame passes into the flues or chimneys, I place another smaller grate b, on
which I maintain a fire of charcoal, coke, or coals, which have been previously
burned, until they have ceased to smoke, which by giving intense heat, and
admitting some fresh air, consumes the smoke of the last fire.”
Thompson's Patent.—Mr. Thompson had a patent in 1796 for a furnace on
the same principle as Watt's, but it was a less deviation from the ordinary con-
struction. The fire-bars were made about one third longer than usual, and at
two-thirds of their length from the front a low arch was thrown across the
fire-place, under which the smoke rushed from the fore part of the fire, and
was thus impelled through some intensely heated coked fuel, lying under and
beyond the arch upon the bars, and was thereby consumed. By the manage-
ment of a good stoker, this fire-place appears to us calculated to answer well.
Roberton's Patent.—In 1801 Messrs. Roberton, of Glasgow, patented some
improvements upon Mr. Watt's plans, which rendered the apparatus more com-
plete and convenient. To these gentlemen, indeed, is usually attributed the
first successful application of the principle patented by Watt, of burning the
smoke owing, we are inclined to believe, to the indifference of the public
in the early part of Mr. Watt's career to the nuisance of dense smoke; as,
from the comparatively small number of engines at that time, the adoption of
means to burn the smoke was not so much sought after. Joined to this cir-
cumstance may be reckoned the unskilful manner in which bricklayers, pre-
tending to an adequate knowledge of the subject, executed the work; which
caused the principle to get into disrepute, rather than the bungling attempts to
carry it into effect. It was, in consequence, given in evidence, by numerous
witnesses before a committee of the House of Commons, that more coals were
consumed by burning the smoke than allowing it to pass off unconsumed ! in other
words, that inflamed gas afforded less heat than cold smoke. The probability
is, that more air was admitted than was requisite to supply the necessary
quantity of oxygen to the carbonaceous matter, and that in consequence of such

576 FURNACIES.
management, the temperature of the furnace or of the boiler was reduced,
requiring an additional quantity of fuel to get up the requisite heat.
Sheffield's Patent.—In the year 1812, Mr. William Evetts, of Sheffield, took
Qut a patent for improved reverberatory furnaces for melting metals, in which
he introduced what he termed an air conductor, for the purpose of conveying a
stream of pure air upon the surfaces of the metallic substances under reduc-
tion. This air conductor consisted of a vertical passage or tube, made in the
bridge or wall of brickwork at the back of the furnace, the lower end of which
opened into the ash pit, where it was widened, and the size of the aperture
regulated by a valve, which valve was operated upon by a long rod passing
through the front enclosure of the ash pit; the upper extremity of the air tube
or passage did not pass vertically through the bridge, but had a horizontal turn
given to it, by which the jet was thrown upon the substances under operation,
or against the current of heated vapours, before they passed over the bridge;
and this minor stream of fresh air was found to impart sufficient oxygen to the
carbonaceous matter of the smoke, and burn it.
Legislative Enactment.—The annoyance and permicious effects experienced by
the public from a sooty atmosphere, drew the attention of the legislature to the
subject, and a Select Committee of the House of Commons was appointed, in
1819, “to inquire how far it might be practicable to compel persons using
steam engines and furnaces in their different works, to erect them in a manner
less prejudicial to public health and comfort; and to report their observations
thereon to the House.” The committee having ascertained and reported to the
House that the reduction of smoke from furnaces might be practically accom-
plished, a bill to embrace that object was brought into the House and passed;
it was entitled—“An Act for giving greater facility in the prosecution and
abatement of nuisances arising from furnaces used in the working of steam-
engines:", to commence Sept. 1, 1821. Among its enactions are the follow-
ing;—“That it shall and may be lawful for the court before whom any such
indictment shall be tried, in addition to the judgment pronounced by the said
court, in case of conviction, to award such costs as may be deemed proper and
reasonable to the prosecutor or prosecutors, to be paid by the party or parties
so convicted.” It was also enacted—“That if it shall appear to the court before
which any such indictment shall be tried, that the grievance may be remedied
by altering the construction of the furnace, or any other part of the premises
of the party or parties so indicted, it shall be lawful to the court, without the
consent of the prosecutor, to make such order touching the premises as shall
be, by the said court, thought expedient for preventing the nuisance in future,
before passing final sentence upon the defendant, or defendants, so convicted.”
Gregson's Patent.—Mr. Joseph Gregson, who was one of the gentlemen
examined before the Committee of the House, gave it as his opinion, that the
principal causes of the nuisance were, the putting on the fire too much crude
fuel at a time, and the chimney being in general too low. Mr. Gregson had a
patent for a plan of a furnace for consuming the smoke, the principle of which,
he stated, consisted, “first, in causing all the smoke, after it has arisen from the
fire, to return into the heat of the fire before it enters the flue or chimney, and
so be consumed; secondly, in putting on no more fuel at any one time, than
the smoke of which can be consumed, and that without opening the door for
the purpose; thirdly, in supplying the fire with a current of air to coun-
teract the effect of those winds that operate against the draft. The engraving in
the next page represents a vertical section of the apparatus. The fire-place G and
the feeding-door F are made as usual; the smoke passes over the bridge D,
under which is an aperture, where an intense heat is produced, which inflames
the smoke in the descending flue by means of a supply of air through the
aperture C; it then passes into the flue and the chimney, A, formed in the
usual manner. ZZ is an air shaft and drain to supply the fire with air through
a valve situated under the fire-place. It may be deserving of remark, that
the objects aimed at by Mr. Gregson in this arrangement would be considerably
promoted, by making the partition between the ascending and descending fluº;
A and Z, of iron or copper, instead of brick; and that an economy of fuel
FURN ACES. 577
would result from the partial exchange of temperatures between the opposite
currents. But in thus abstracting the waste heat through the medium of good
conducting substances, a sufficient temperature must be left in the ascending
column to maintain the draft. -
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Losh's Patent.—The entire specification of this gentleman's improvements
is inserted in the Repertory of Arts, and is deserving of perusal by those who
are interested in the subject; the leading arrangements may however be un-
derstood by the following extract. . . . The plan arranges “the furnace
bars as near as possible under the middle of the boiler, or other vessel's bottom,
and to have the aperture or apertures for the escape of the rarefied air and
smoke above the door through which the fuel is put in, so that the heated air
and gases, by their expansive force and diminished specific gravity, shall pre-
vent the cold air of the atmosphere from penetrating beneath the bottom of the
boiler, in order that the cold air admitted at the door where the fuel is intro-
duced, shall, in its passage to the chimney, have no tendency to mix with the
leated gases until after they have ceased to act upon such parts of the boiler
as are required to be submitted to their action alone. A division of cast plates,
extending from the ends of the bars next to the door, separates the grate-room
from the ash-hole and air-duct, and prevents any air from passing into the
grate-room which does not pass through the ignited fuel.” Another peculiarity
in Mr. Losh's arrangements, consists in the employment of two fires, which we
will call A and B, with a wall between them, which supports the middle of the
boiler across its width. Each of these fires has a common flue, which termi-
nates in the chimney, and they communicate with each other by means of an
open arch under the partition wall; each fire is supplied alternately with fuel;
and the arrangement of the dampers is such, that the gas from the fresh fuel
in A shall be compelled to descend, pass under the arch of the division wall,
and through the grate bars of the fire B, along with the fresh air that supplies
it where the smoke is consumed; the current of heated air from both, thus
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578 FURN ACES.
united, takes its course around the flue into the chimney. By the time that
the fuel in A has burned bright, that in B requires replenishing; the dampers
are then reversed, which removes the current to the chimney; then the gas
from the fresh fuel in B descends under the beforementioned arch up through
the grate bars of A, along with the fresh air of supply, and being thereignited,
is conducted to the chimney. In this alternate manner the operation of feeding
is continually repeated.
Steel's Improvement.—Mr. Steel's fire-place was of a circular form, and made
to revolve on an upright axis by a gear connected to its lowest extremity;
motion was also given, at the same time, to a fluted roller, turning in bearings
underneath a hopper filled with coals; this roller broke or crushed the coals to
a sufficiently small size, and projected them down an inclined shoot, which dis-
tributed them over the circular grate as it turned round, as represented in the
annexed section. o o o shows a high pressure tubular boiler, set in masonry;
§
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i i is the ring or rim which surrounds the circular grate, made somewhat deeper
than the bars, and turning round in an iron trough 33, filled with sand, which
prevents the air from passing by the rim; N is a metallic plate to receive the
ashes which fall; D a toothed wheel, turned by any convenient means in the
step at C, and in a cross bar at L above. At F is the receptacle for the fuel;
E the breaking and supplying roller, which projects them down the inclined
shoot G R, into the revolving grate, which, continually presenting fresh surfaces,
*-














FURN ACES. 579
the fuel is pretty uniformly distributed thereon. The grate is made to turn in
such a direction that the fresh coals are, immediately after they are deposited,
presented to the fire door contiguously situated, where, by the due admission of
air, vivid combustion immediately takes place, and the fresh fuel is in bright
ignition before more is thrown on the same part, the revolution of the grate
being low.
Brunton's Patents.-Mr. Brunton had a patent in 1819 for a revolving fire-
grate of a similar kind; but whether Mr. Steel's was antecedent to it (as would
appear from the dates given, together with the circumstances), we do not know.
Mr. Brunton has, however, the credit of carrying his apparatus into successful
use, and of having rendered it very complete. Among many judicious con-
$rivances, may be noticed a revolving scraper, which gathered up the ashes as
they fell upon the ash plate. In the following year, 1820, Mr. Brunton took
out a second patent for improvements upon the former; these chiefly con-
sisted in a mode of raising or lowering the furnace at pleasure, so as to diminish
or increase the heat of the boiler as required; also in a new mode of feeding
the fire. The shaft of the circular fire-grate upon which it revolves, is made
to pass through a hole in a bearer of iron, built in the brickwork, and receives
its support at bottom upon another bearer of iron, which is capable of sliding
up and down in grooves, so as to elevate or depress the fire, by means of a rack
and pinion, acted upon by a lever or winch. Round the periphery of the cir-
cular grate is a double rim of sheet-iron, rising up three or four inches, the space
between being filled with sand, so that when the grate is raised, another ring of
iron, attached to the wall of the furnace, may fit into the groove and form a sand
valve, to prevent the passage of air, and check the transmission of heat. Two
or more passages, provided with sliding doors, are made through the brickwork,
for the purpose of admitting a current of air to the top of the fire, in order to
assist in igniting the smoke, if necessary. The fire feeder is shaped like a
hopper, placed over the feeding hole, and the delivery aperture at bottom is
capable of contraction or expansion, as may be required. Below this is a plate
of iron, placed in an inclined position, and suspended upon pivots for the pur-
pose of being agitated, in order to distribute the fuel equally upon the grate;
there is also a shovel upon rollers, moved by means of a rod and chain
actuated by the engine. By the very equal distribution of the coal upon the
grate, a thin fire and a sharp draft is maintained, owing to every piece of
coal upon the grate being successively exposed to a current of the fire
passing constantly in one direction across the grate; the continual dropping
of the coal in minute quantities, instead of opening the door to charge as
usual, produces a great advantage in convenience, besides a saving of fuel.
The introduction of the coal is likewise completely governed by the steam
generated, so as to admit no more for combustion than is actually needed for
the due performance of the work of the engine. The whole apparatus acted
independently of the skill or of the carelessness of the fireman. Small coal,
of greatly inferior cost to that generally used, answers well with a furnace
of this kind, and thereby effects an important saving. A thin fire with a sharp
draft produces the maximum effect, because the greater the quantity of
oxygen brought into contact with the coal in combustion, the greater heat is
obtained.
Murray's Improvement.—It has doubtless been observed by most of our
readers, that the very dense black smoke which issues from the chimneys of
steam engines and other furnaces, is not constant; that it commences at the
time of putting on fresh fuel, and continues for a few minutes afterwards. At
this time the air finds its way through the fuel with less opposition, and the
evolution of dense smoke ceases until the next charge of coals. To supply the
requisite quantity of air to burn this black smoke, the late Mr. Murray (the
celebrated steam-engine manufacturer of Leeds), devised a very ingenious
machine. It is described in a letter addressed to the Editor of the London
Journal of Arts, dated February 15, 1821, wherein he observes, -“The most
effectual method yet known for consuming smoke, is by the admission of a large
quantity of air to the hottest part of the fire, at the time the smoke is bursting
580 FURN ACES.
from the recent charging of coal. The necessary quantity of air to be admitted
ought not to be less than may pass through an aperture of four square inches
for each horse power that the boiler or fire is equal to ; this will consume the
smoke in from three to five minutes, according to the quantity and quality of
coal put on at each time;--the times of charging being not more, than five
times in an hour, nor less than three. The air rushing into the flue is the
moving force for giving motion to my new regulating machine, which continues
in motion during the consumption of smoke, but no longer.” The machine
may be thus described, without the drawings given in the work before alluded
to. It consists of a light fan-wheel, from which proceeds a capacious tube,
communicating with the fire-place, and containing a turning valve, which opens
or closes the passage. When the fire-door is opened to take in-fresh fuel, it
discharges (by means of a slip catch connected to the door) a pall, which sets
at liberty a suspended weight; the descent of this, turns a ratchet wheel,
which places the turn-valve edgeways against the current, and leaves a free
communication between the atmosphere and the upper side of the fire. In this
state of rest the machine remains until the fire-door is shut, when the current
of air enters the machine, turning rapidly the fan-wheel, which having a pinion
on its axis of only one tooth, gives a slight motion to a light spur-wheel of
many teeth; this wheel, through the medium of a catch-rod, and other simple
mechanism, gradually closes the turn-valve. The smoke having been consumed,
the fire continues burning until a fresh supply of fuel is necessary, when the
fire-door is opened, which puts the machine in a state for measuring off the
required quantity of air to be admitted to consume the smoke of each charge ;
the operation is then repeated.
Pritchard's Patent.—Mr. William Pritchard took out a patent in 1821 for
the same object. He fixed a small cylinder in some convenient place con-
tiguous to the furnace, with an air-tight piston to rise and fall within it. At
the upper end of the piston-rod a chain is attached, which passes over pulleys,
and its reverse end is connected to the top of the fire door or air-flue doors,
by means of which connexion, when the fire door is raised, the piston descends
in the cylinder by its own gravity; and when the fire door is shut down, the
piston rises. On the outside of the cylinder is placed a branch pipe or channel,
through which the air passes (as the piston ascends or descends) from the upper
to the lower part of the cylinder, and vice versä. In the middle of this branch
pipe is a valve or stop-cock, which may be so adjusted as to suffer the air to
pass slowly, or by a very small stream, through the channel; by this means
the ascent of the piston is retarded, and hence the entire descent, or closing of
the fire doors, or air-flues, does not take place, until the air is nearly all expelled
from the upper part of the cylinder, allowing time for the requisite quantity of
atmospheric air to pass into the air-flues over the fire, for the purpose of con-
suming the smoke; the time of closing the doors is regulated, as above, by
the valve or stop-cock in the branch pipe.—London Journal of Arts.
Stanley's Patent.—This invention, which we have seem repeatedly and suc-
cessfully applied, forms a distinct appendage to the front of the furnace. At
the upper part of the apparatus is a hopper, containing a supply of small coals
adequate to an hour or two's consumption. Through an aperture at the lower
extremity of this vessel, the coals drop between two grooved rollers, which
revolve in opposite directions, and break those which are too large to pass
without reduction between them; they then fall upon a flat plate of iron, whence
they are continually projected by the arms of a kind of revolving fanner, which
scatters them evenly over the burning fuel on the grate, where it lies in a thin
bed, in order that the air may pass upward through them the more easily. The
apparatus is, however, usually adjusted to throw a larger proportion of the fuel
near the fire bridge, so that it may lie there heaped up or in a thicker stratum.
in order that the small quantity of smoke arising from the fresh fuel in front
may be consumed in passing over the bridge.
Chapman's Purnace.—In 1824 Mr. Chapman received a reward from the
Society of Arts for a different mode of introducing air into the furnace. He
casts the grate bars hollow from end to end, so that they form a series ...”
FURNACES. 581
parallel tubes, which open into two boxes, one placed in front, and the other
behind the grate. In the front box, directly underneath the fire door, there is
a register to open and shut to any extent, at pleasure; the other end is con-
nected with the brickwork, directly under the fire bridge, which fire bridge is
made double, with a small interval between, about one inch, the interval to go
across the furnace from side to side, and rather to incline forward, or towards
the fire door, so as to meet and reverberate the smoke on to the ignited fuel in
the grate, which causes it to inflame and become a sheet of bright fire under
the bottom of the boiler. By this arrangement it will be perceived, that if the
front register is open, or partially so, there will be a great draft of air through
it, along the intérior of the grate bars, thence into the flue of the fire bridge,
and out of the orifice at top, which air will be heated in its passage through the
bars before it comes in contact with the smoke, when it will give out its oxygen,
and cause it to inflame. Mr. Chapman's mode of supplying the coals to the
furnace is also simple and excellent, which will be explained with reference to
the subjoined engraving. Fig. 1 is a section of the furnace, with a boiler
Fig. 1.
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fixed therein; and Fig. 2 a view of the hollow bars as they open into the box i.
a is the boiler; b the fire-place; c the feeding hopper, with a cover d, and its
type or turning bottom, having a lever or counterpoise e, by means of which
the coals are delivered into the fire-place; f is a rake, by means of which the
half-burnt coals are pushed forward previously to letting in a fresh charge; g a
slit below the furnace door, through which the state of the fire is seen; i i is an
air-tight box, into the back of which the bars open, and in front of which is a
register for the admission of air; k one of the hollow bars, the whole of which
are shown in Fig. 2 as they open into the box i above mentioned; l a flue in
the fire bridge, through which the air having passed into the box i, and thence










































'4 E
582 FURN ACES.
through the hollow bars k, enters into the furnace, and consumes the smoke.
Hollow bars are said to be more durable than solid.
Gilbertson's Patent.—This differs but little from the former. Mr. Gilbertson's
plan is to heat the air by causing it to pass through “hollow plates” fixed to
the sides of the furnace, and thence into a cavity at the back of the fire, where
it comes in contact with the smoke, and causes it to be ignited. -
, Chemical Furnaces.—The forms of furnaces employed by experimental as
well as practical chemists are extremely diversified. Those which are employed
in manufactories; in metallurgical, distillatory, and other operations on the great
scale, will be found under the denomination of the article produced, such as
IRoN, GAs, ZINc, &c. In this place, therefore, we shall confine our notice to
those portable furnaces which are generally employed by British chemists.
Reverberatory Furnace.—Annexed is the common reverberatory furnace. At
a a is the ash pit and fire-place; b b the body of the furnace; c c the dome or
d
• * *** * ~...
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reverberating roof; d the chimney; e door of the ash pit; f door of the fire-
lace; g handles of the body; h aperture to receive the head of the retort; ;
his of the dome; k receiver; l stand of the receiver; m retort, represented
in the body in dotted lines. . -
Aikin's Portable Blast Furnace is represented in the figure on the following
i. , it is composed of three parts, all made out of the common thin black
ead melting pots, sold in London for the use of the goldsmith. The lower
i. c, Fig. 1, is the bottom of one of these pots, cut off so low as only to
eave a cavity of about an inch deep, and ground smooth above and below.
The outside diameter, over the top, is five inches and a half. The middle-piece,
or fire-place a, is a larger portion of a similar pot, with a cavity about six
inches deep, and measuring seven inches and a half over the top outside
diameter, and perforated with six blast holes at the bottom. These two pots
are all that are essentially necessary to the furnace for most operations; but
when it is wished to heap up fuel above the top of a crucible contained, and
especially to protect the eyes from the intolerable glare of the fire when in full
height, an upper pot b is added, of the same dimensions as the middle one, and
with a large opening in the side, cut to allow the exit of the smoke and flame.
It has also an iron stem with a wooden handle (an old chisel answers the pur-
pose very well,) for removing it occasionally. The bellows, which are double
(d), are firmly fixed by a little contrivance, which will take off and on, to



FUSEE. 583
a heavy stool, as represented; the nozle is received into a hole in the pot c,
which conducts the blast into its cavity. No luting is necessary in using this
furnace, so that it may be set up and taken down immediately. Coke, or
common cinders, answer well for fuel; and the heat which this little furnace
affords is so intense, that its power was first discovered by the fusion of a thick
piece of cast-iron.
Chevenia's Wind Furnace is represented in the following engraving. It is, in
some respects, Dr. Ure observes, to be preferred to the usual form. The
sides, instead of being perpendicular, are inclined, so that the hollow space is
pyramidical. At the bottom the opening g
is thirteen inches square, and at the top $
eight. The perpendicular height is seven-
teen inches; the form appears to unite the
following advantages: 1st, A great surface
is exposed to the air, which, having an easy
entrance, rushes through the fuel with
great rapidity; 2d, The inclined sides act
in some measure as reverberating surfaces;
and 3d, The fuel falls of itself, and is
always in close contact with the crucible
placed near the grate. The late Dr. Ken-
nedy, of Edinburgh, whose opinion on this
subject claims the greatest weight, found
that the strongest heat in our common wind furnaces was within two or three
inches of the grate: this, therefore, is the most advantageous position for the
crucible, and still more so when we can keep it surrounded with fuel. It is
inconvenient and dangerous for the crucible to stir the fire often to make the
fuel fall; and the pyramidal form renders this unnecessary. It is also more
easy to avoid a sudden bend in the chimney, by the upper part of the furnace
advancing in this construction.
Lamp. Furnaces.—The flame of an argand lamp is very often employed for
chemical purposes, and it is very convenient. To a vertical rod is fitted to slide
thereon a number of metallic rings projecting from it horizontally, which
become the supports to retorts, or other vessels suspended over the flame of
the lamp.
ºn. Furnaces, such as stoves, grates, ranges, &c. are described under
the article FIRE-PLAce.
FUSEE, in Clockwork, the conical barrel drawn by the spring, and about
which the chain or cord is wound; for the use of which see Horology. -


584 GALLON.
FUSION, in Chemistry, the application of heat to produce the dense fluid
state of bodies.
FUSTIAN, in Commerce, a kind of cotton stuff, which seems as if it were
whaled on one side. Right fustians should be made entirely of cotton; but they
are frequently made with a warp of flax.
FUSTIC, or YELLOW WOOD. This wood, the Moras tinctoria, is a
native of the West Indies, and affords much colouring matter, which is very
permanent. The yellow given by fustic without any mordant is dull and
brownish, but stands well. The mordants employed with weld act upon fustic
in a similar manner, and by their means the colours are rendered more bright
and fixed. The difference between them is, that the yellow of fustic inclines
more to orange than that of weld; and as it abounds more in colouring matter,
a less quantity will suffice.
G. * f
GALBANUM. A resinous and gummy juice that exudes from the Bubon
galbanum. The commercial article is in the state of white, yellow, and brownisa
tears, unctuous to the touch, and softening between the fingers, and generally
full of bits of stalks, leaves, &c. of the plant; it has a bitter acrid taste, and
strong smell. One pound of galbanum yields to alcohol nine and a half ounces
of resin, and to water about three ounces of gum. The peculiar smell and
taste of galbanum reside in an essential oil, six drachms of which are obtained
by distillation from one pound of the substance.
GALENA. The native sulphate of lead. -
GALLEY, in Printing, a frame into which the compositor empties the line
of type out of his composing stick, and in which he arranges and ties up the
whole matter of the page when it is completed. The galley is an oblong square
board, with a ledge on one of its sides and one of its ends, to support the type
in drawing it up into a compact mass; it has sometimes a groove to admit a
false bottom, called a galley-slice.
GALLEY. A kind of low, flat-built vessel, furnished with a deck, and navi-
gated with sails and oars; chiefly used in the Mediterranean. This term is also
given to a light species of open boats employed in the river Thames, which is
rowed with six or eight pair of oars. -
GALLIC ACID is found most abundantly in the vegetable substance galls
whence it derives its name; but most astringent vegetable matter contains it.
The simplest mode of obtaining it is probably that recommended by Mr.
Fiedler. An ounce of powdered galls is to be boiled in sixteen ounces of
water until reduced to eight, and then strained. Dissolve two ounces of alum
in water, precipitate the alumina by carbonate of potash; and after edulcorating
it completely by repeated ablutions, add to it the decoction, frequently stirring
the mixture with a glass rod; the next day filter the mixture; wash the pre-
cipitate with warm water till this will no longer blacken sulphate of iron; mix
the washings with the filtered liquor, evaporate, and the gallic acid will be ob-
tained in fine needle crystals. The gallic acid, placed on a red-hot iron, burns
with flame, and emits an aromatic smell like that of benzoic acid. It is soluble
in twenty parts of cold water, and in three parts at a boiling heat. It is more
soluble in alcohol, which takes up an equal weight if heated, and one-fourth of
its weight cold. The distinguishing characteristic of gallic acid is its great
affinity for metallic oxides, so as, when combined with tannin, to take them
from the powerful acids. The more readily the metallic oxides part with their
oxygen, the more they are alterable by the gallic acid. To a solution of gold
it imparts a green hue; mercury it precipitates of an orange yellow ; copper,
brown; bismuth, a pale yellow; lead, white; and in iron, a black; whence its
use in making ink, and in the operations of the dyer in making various shades
of black, and in improving or fixing other colours. -
GALLON. An English measure of capacity, which, until recently, varied
considerably with the kind of goods measured by it; thus— sº
GAS. 585
The gallon wine measure contained 231 cubical inches.
Ditto beer measure, 95 282 93
Ditto dry measure, 35 268: 35
But by an Act of Parliament passed in 1824, it was altered on the 1st of May,
1825, to an uniform measure called the imperial standard gallon. By that act
it was determined to be such measure as shall contain ten pounds avoirdupois
of distilled water, weighed in air at the temperature of 620 Fahr., and the
barometer at 30 inches; and such measure is declared to be the “Imperial
Standard Gallon,” and shall be the unit and only standard measure of capacity to
be used, as well for wine, beer, ale, spirits, and all sorts of liquids, as for dry goods
not measured by heap measure; and that all other measures shall be taken in
parts or multiples of the said imperial standard gallon, the quart being the
fourth part of such gallon, and the pint one-eighth part; two such gallons
making a peck, eight such gallons a bushel, and eight such bushels a quarter of
corn, or other dry goods not measured by heaped measure.
GALLS. The protuberances on various kinds of trees, supposed to originate
in the puncture of an insect. Some are hard, and are therefore called nut-
galls; others soft, which are called berry, or apple-galls. The best are the nut-
galls of the oak; and the most esteemed of this species are brought from
Aleppo. They are not smooth on the surface, but tubercular, small and heavy,
and should have a bluish or blackish tinge. By infusing 500 grains of Aleppo
grains broken into small pieces in distilled water, Sir H. Davy obtained, by
evaporating the fluid, 185 grains of solid matter, which, on analysis, gave 130 of
tannin; 12 mucilage and insoluble matter; gallic acid, with a little extractive
matter, 31; remainder calcareous earth and saline matter, 12. The extensive
use of galls in dying, tanning, and in making ink, is well known, for which see
the separate articles under their initial letters.
GALL-STONES. The calculous concretions occasionally found in the
gall-bladders of animals. Those found in oxen, used by painters, are of this
nature.
GALVANISM. A species of electricity excited, not by friction, but by
establishing a communication between two different metals through the medium
of a liquid. See CHEMISTRY.
GAMBOGE. A substance obtained from the Stalagmites cambogioides, a
tree that grows wild in the East Indies, from which it is had by wounding the
shoots. It is brought here in large cakes, which are yellow, opaque, and
brittle. With water it forms a yellow, turbid liquid, used in painting. In alcohol
it is completely dissolved. If taken internally, it operates violently as a
cathartic.
GARLIC. The root of the Allium. This root has been found, by chemical
analysis, to consist of albumen, mucilage, fibrous matter, and water.
GARNET, in Mineralogy, a species of the flint genus, of which there are
two sub-species, viz. the precious and common. The precious, or oriental, is
red, but of various shades; it occurs most commonly crystallized, either as a
dodecadron, or as a double eight-sided pyramid. Garnets are found in almost
every country where primitive rocks exist. Switzerland and Bohemia are the
two countries which furnish them in the most abundance.
GAS. The name given to all elastic aeriform fluids (except the atmospheric
air) which retain that state at all ordinary temperatures and pressures. For a
long time the gases were supposed to be permanently elastic ; but about the
year 1823 Sir Humphrey Davy, assisted by Mr. Faraday, succeeded in reducing
several of them to a liquid state by subjecting them to great pressure, and an
extreme degree of cold; upon removing the pressure, and restoring the natural
temperature, the liquids became again converted into gases. This discovery
induced these gentlemen to institute a series of experiments with the view of
ascertaining whether the vapours arising from the gases thus liquefied might not
be rendered available as mechanical agents in lieu of steam, and be applicable
to the same purposes. These experiments were detailed in a paper read at the
Royal Institution, and from this paper we select the following results:—
- Sulphuretted Hydrogen, which condenses readily at 3° Fahr, under a pressure
586 GAS LIGHTING.
equal to the elastic force of an atmosphere compressed to one-fourteenth, had
its elastic force increased to that of an atmosphere compressed to one-seven-
teenth by an addition of 470 of temperature. Liquid muriatic acid at 3°Fahr.
exerted an elastic force of 20 atmospheres; by an increase of 229 of tempera-
ture, its force was increased to 25 atmospheres; and by a farther addition of
269, its force became equal to 40 atmospheres. Carbonic acid at 12° Fahr.
exerted a force of 20 atmospheres; and at 320 Fahr. its pressure was equal to
36 atmospheres, making an increase of pressure equal to 13 atmospheres by
an increase of 200 of temperature; and this immense force of 36 atmospheres
being exerted at the freezing point of water. From the above experiments, it
will be seen that great accessions of force are obtained by very slight additions
of heat; and Sir Humphrey observes, in the Memoir, that—“if future experi-
ments should realize the views here developed, the mere difference of tempera-
ture betwixt sunshine and shade, and air and water, will be sufficient to
produce results that have hitherto been obtained only by a great expenditure
of fuel.” Upon this subject Mr. Tredgold, in his excellent Treatise on the
Steam Engine, observes, “I think it will be found that two other circumstances
should be considered in estimating the fitness of compressed gases as me-
chanical agents. First, the distance through which the force will act; for if
this distance of its action be less in the same proportion as its force is increased
by compression, no advantage will be gained; the power of a mechanical agent
being jointly as its force, and the space through which that force acts.
Secondly, the quantity of heat required to produce the change of temperature,
is also to be considered; for if the mechanical power requires as great an
expenditure of heat as common steam, no advantage will be gained; in fact,
the only prospect they afford of being useful, is through lessening the extent of
the surface to be heated.” Mr. Tredgold then gives the following Table of the
gases liquefied by Mr. Faraday, with their densities as far as can be ascer-
tained, and with a column to show their mechanical power as compared with
steam, according to the spaces through which they act, from which it will be
seen that in effect they are all inferior to the latter. The quantity of fuel requi-
site for their vaporization is not known.

Spec. Grav.
Spec. Grav. of Liquid, Tempera- Pressure in
Air—1. Water—1. ture. Atmosphere
Carbonic acid gas 1.527 320 36
Sulphuric acid gas . . 2,777 1.42 45 2 426
Sulphur. hydrogen gas . 1.192 .9 50 17 530
Euchlorine gas . . 2.365
Nitrous oxide . . 1.527 45 50
Cyanogen . . 1.818 .9 45 3.6 395
Ammonia . o .596 .76 50 6.5 1057
Muriatic acid gas. 1.285 50 40
Chlorine . º . . 2,496 1.33 50 4 440
| Steam of water .48 1.000 212 1. 1711
\
Prº-
GAS LIGHTING. The art of procuring and applying to the purpose of
illumination the inflammable gases evolved by animal and vegetable matter
when exposed in close vessels to a high temperature. This important and
highly beneficial invention originated in the researches of modern chemists;
but a long period, elapsed between the scientific discovery of the facts upon
which the process is founded, and their successful application to practical pur-
poses. The fact that a permanently elastic and inflammable aeriform fluid is
evolved from pit coal during its destructive distillation, appears to have been first
ascertained experimentally by the Rev. Dr. Clayton, whose account of his dis-
govery was published in the Transactions of the Royal Society, Vol. XLI., for
the year 1789. Dr. Hales subsequently made experiments on pit coal, and
found that, when distilled in close vessels, nearly one-third of the weight of coal
GAS LIGHTING. * 587
assed off in inflammable vapour. ... Further experiments were made by Dr
atson, Bishop of Llandaff, in 1767; but no practical application appears to
have been made of these discoveries for a long period. The merit of such
application appears to belong to Mr. Murdock, who, in 1792, commenced a
series of experiments at Redruth, in Cornwall, upon the quantity and quality
of the gases contained in different substances, as coal, peat, and wood; in the
course of which experiments it occurred to him, that, by confining and con-
ducting the gas in tubes, it might be employed as an economical substitute for
lamps and candles. The distillation was performed in iron retorts, and the gas
conducted through tinned iron and copper tubes to the distance of seventy feet.
At this termination, as well as at the intermediate points, the gas was set fire
to as it issued through apertures of different diameters and forms, purposely
varied to ascertain which would answer best; amongst these forms were the
argand burner and the cockspur burner, which are the two most generally
employed at the present day. Bags of leather and of varnished silk, and vessels
of tinned iron, were also filled with the gas, which was set fire to and carried
from room to room, in order to ascertain its applicability as a movable light.
Mr. Murdock's constant occupations prevented his pursuing the subject further
until 1797, when he renewed his experiments upon coal and peat, at Old Cum-
nock, in Ayrshire. In 1798 he constructed an apparatus for lighting the works
of Messrs. Bolton and Watt, at Soho; and in 1802, on the occasion of the re-
joicings for the peace, the whole of the works were illuminated with gas. In
1803 and 1804 Mr. Winsor made public exhibitions of the general nature of
gas lighting at the Lyceum Theatre, and proposed to light the public streets by
means of gas; but the extravagance of his statements respecting the advan-
tages of the scheme were prejudicial to the plan; and although an experiment
was made by lighting up a portion of Pall Mall, it was soon abandoned, and
the practice did not come into successful operation until the year 1813, when
the Chartered Gas Company erected their works at Peter-street, Westminster.
Since this period the practice of gas lighting has come into general use with
astonishing rapidity; important improvements have been made in the various
processes connected with it, and gas is now extensively procured from numerous
substances beside pit coal, such as oil, tar, resin, &c. We shall now proceed
to give a general view of the subject, by describing the process of gas making
as usually conducted at the Coal Gas Works.
A number of cast-iron vessels, called retorts, generally of a cylindrical or of
an oval shape, and set in a brick furnace, are heated to redness, and then about
half filled with coal, and the mouths of the retorts closed and carefully luted.
In a short time the decomposition of the coal commences, and the volatile parts
separating from the fixed parts, are conducted by bent tubes called dip pipes,
into a large horizontal cast-iron tube called the hydraulic main, from its being
half full of water, into which the ends of the dip pipes are immersed, so that
the gas and vapours may be forced to pass through the water, which condenses
a portion of the tar and ammonia, whilst the gas ascends to the upper part of
the hydraulic main ; from this it passes by a pipe to the condenser, which
consists of a number of metallic pipes or compartments, surrounded by cold
water. In its passage through this vessel the gas becomes so much cooled as
to occasion the remaining portion of the tar and ammonia to be condensed,
which latter products pass into the tar cistern, whilst the gas passes into the
purifier, where it undergoes a process by which the carburetted hydrogen, which
is the gas employed for illumination, is freed from the sulphuretted hydrogen,
and carbonic acid evolved with it; it then passes through the gas meter, in
order that the quantity may be registered on its way to the gas holder (or
gasometer, as it is improperly called), in which it is stirred up till wanted for
use, being conveyed in any required direction by pipes connected with the
gasometer. For the further elucidation of the subject, a general view of the
apparatus, with explanatory remarks, will be found on the following page. a
Fig 1. in the following engraving, represents a portion of a bench of retorts, in
which five elliptical retorts b b are exhibited, set in an oven, the mouth of which
is covered by the cast-iron plate c, having apertures for the introduction of the
588 GAS LIGHTING.
retorts, which are secured to the oven plate by flanges at their mouths, and the
other extremity is supported by a cast-iron stud projecting from it and resting
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in a cast-iron socket at the back of the oven. This plan of setting retorts,
º


























































GAS LIGHTING.. " 589
which affords great facilities in their removal when burnt out, and in replacing
them with others, was first employed at the Westminster Gas Works, and is
the invention of Mr. Malam, of that establishment. The fires for heating the
retorts are not seen, being situated at the back of the oven, by which arrange-
ment the annoyance of the heat to the men who charge the retorts from the
elevated platform d, is considerably diminished; the coke, as it is raked from
the retorts, falls through apertures e e in the platform, to which apertures are
fitted trap doors, or movable gratings; ff are the dip pipes, by which the gas
enters the hydraulic main g, a transverse section of which, upon a larger scale,
is shown in Fig. 2; h is the pipe by which the gas is conveyed from the
hydraulic main to the condenser, to be divested of the tar and ammoniacal
liquor. Various arrangements have been employed for this purpose; that
shown in the engraving, and which we believe to be generally preferred, is the
invention of Mr. Perks, and consists of a close vessel k divided into compart-
ments ll, each communicating with the adjacent one by parallel rows of bent
pipes m m, which are surrounded by water contained in the tank n, erected upon
the top of k. The gas entering the condenser by the pipe h passes succes-
sively through the several rows of bent pipes until it arrives at the exit pipe o,
which conveys it to the purifier; by which prolonged contact with a great extent
of cooling surface, the tar and ammoniacal liquor become condensed, and fall to
the bottom of the compartments l l, and from them are conveyed to the tar
vessel p, in which the tar, from its greater specific gravity, occupies the lower
portion, and is drawn off by the lower cock, whilst the ammonia, which lies
above it, is drawn off by the upper cock; q represents the most approved con-
struction for a purifier when cream of lime is the material by which the car-
buretted hydrogen is freed from the sulphuretted hydrogen and carbonic acid,
with which it is still contaminated after leaving the condenscr. In this arrange-
ment of the purifying vessels, three cylindrical vessels r r r are placed one over
another, and from the top of each descends a smaller cylinder s ss, which does
not reach the bottom of the larger cylinder, and which has attached to its lower
end a broad flange or shelf. The larger cylinders are filled with cream of lime
to about one-half their depth, which is kept in constant agitation by broad vanes
t t attached to the spindle u, passing through stuffing boxes in the several
cylinders. The gas entering the lower small cylinder by the pipe o depresses
the liquid therein below the shelf, and then rises up through the fluid into the
upper part of the outer cylinder; from whence it is conveyed by the bent pipe v
to the second interior cylinder, and from it, in a similar manner, to the third, from
which it escapes, as before described, to the outer cylinder, and from thence
passes by the pipe w to the gasholder, or gasometer w, as it is commonly
termed. The gasholder consists of a large outer cylindrical cast-iron vessel or
trunk y, nearly filled with water, in which is inverted another cylinder z of
sheet iron, a few inches less in diameter, and open at the bottom; the inner is
usually suspended by a chain passing over pulleys, and having counterbalance
weights attached to them, so as to allow the vessel to rise easily by the upward
pressure of the gas upon its entering. For the purpose of suspending the inner
vessel, a heavy frame, or bridge, was formerly erected over the whole; but a
much superior method is now generally employed; in the centre of the vessel
z is a tube of about three feet diameter, through which rises a cast-iron pillar
2 to a plate, on the top of which are fixed the balance wheels, the weights 33
rising and falling within the pillar. From the gasholder the gas is conveyed
by the eduction pipe to the street mains, and from there, or from the various
service pipes branching from them, it is conveyed, by small wrought pipes, to
the street or private lamps. In order to regulate the flow of gas into the main,
at the junction of it with the eduction pipe is placed a regulating valve, and
from the main is supplied a lamp kept constantly burning, whilst an attendant,
by partially opening or closing the valve, maintains the flame of the lamp at the
proper height.
The engraving on the following page represents an improved description of
regulating valve, which has been introduced at the Bath Gas Works by Mr.
Eastwick, the engineer of that establishment. The valve consists of a circular
4 F
590 GAS LIGHTHNG.
plate of metal, nine inches in diameter, sliding over the mouth of the main pipe
in a chamber; the face of the index is a representation of the valve itself, so made
in order that the superintendent may know the precise position of the valve
at any time. The disc A is a thin plate of metal attached to a rod coming up
from the valve behind the index frame, in which there is a slit for the pin,
which carries the index, to pass. The portion of the circle B, which is un-
covered by the disc, represents the aperture or gasway into the main pipe. G
is a pressure gauge connected with the main on the gasometer side of the valve,
and T another pressure gauge, also connected with the main on the town side;
there is a burner supplied from the town side of the valve placed before the
A
|-
eye of the person who adjusts the valve. From repeated inspection of the town
lights at all hours of the night, as well as of the burner before the index, the
requisite pressure is known and regulated; as the night advances, the valve is
lowered more and more, and in the morning (when the lamps ought to be all
out) it is depressed to one-tenth of an inch, that being sufficient to cause the
exit of the gas in the lowest situations.
The opposite engraving exhibits a new construction of a retort and of a puri-
fying vessel, for which Mr. Hobbins, of Walsal, in Staffordshire, obtained a
patent. The objects sought by these new arrangements are, first, an increased
facility of charging and discharging the retort without the necessity of luting
the joints; and a more rapid decomposition of the coal, by spreading it in a thin
stratum equally over the bottom of the retort; and the subsequent purification
of the gas, without employing mechanical labour to produce a constant agita:
tion with the lime or other purifying materials. Fig. 1 shows a longitudinal
section of a retort, supposed to be placed in a furnace occupying the space
between the dotted lines a a ; the two ends of the retort are flanged on to the
body, and, projecting beyond the brickwork, are removed from the influence of

GAS LIGHTING. 591
the fire; b and c are two scrapers, with long rods attached to them, which pass
through the flanged ends of the retorts, and have cross handles at their ex-
tremities. From each end of the retort a tube projects horizontally, which
serves to support and guide the scraper rods, which slide through them. The
form of the scraper b is shown by the separate figure 2, and the form of c by
Fig. 3; in each of them are two square notches, which, sliding upon square
bars of iron, placed longitudinally on the upper side of the interior of the
retorts, are thereby suspended to it, and kept uniformly in their proper
positions. . The process of working the retort is as follows:–previous to
charging it, the scraper c is drawn outwards from the body of the retort close
up to its end, and the scraper b is pushed inwards so as to come in contact with
e; both scrapers being then beyond the opening d, the charge of coals is
admitted through the latter by opening the cover e, the scraper b is then drawn
%ack from its position beyond d, and thus spreads the coals in an even layer
over the bottom of that part of the retort exposed to the fire. About a foot
‘rom each scraper, the rods are connected by a solid and a hollow screw, so that
7t-H ==
when the rods are drawn out, they may be renewed by unscrewing them at
these parts. As the distillation of the coal proceeds, the gas escapes by the
tube f and from thence passes through the condenser to the purifying vessels.
When all the gas has been separated from one charge of coals, the scraper c is
thrust forward, pushing before it, and clearing out all the coke, which falls into
the coke box g, from which it may be discharged by the mouth piece h into a bar-
row, and wheeled away. As it is necessary that the apertures at d and h should
be closed air-tight during the extrication of the gas, the lids or doors are lined
with lead, which, being screened from the heat of the furnace, serves to close
the joints as effectually as the troublesome process of luting them at every
charge. Fig. 4 gives an external view of that end of the retort where the coke
is discharged, and Fig. 5 a similar view of that end at which the coals are put
in ; the letters have reference to the like parts in each figure. Fig. 6 gives a


592 GAS LIGHTING.
vertical section of a series of three vessels, i,j }, which constitute the purifying
vessels; the lower parts of them are occupied with a stratum of lime as high
as the dotted line l l ; the impure gas passes from the retort into the tube m, and
by its pressure descending along the bent arm, it passes out at the bell-mouthed
end, and mixes with the lime contained in the vessel i, wherein it deposits
much of its impurity by condensation; from this vessel the gas again rises and
enters the tube n, thence filtering through the second lime vesselj, it reascends
and enters the tube o into the third filtering vessel k; thence it proceeds by the
tube r, to the gasholder, for subsequent distribution. The covered tubes ppp
above the filtering vessels are for the purpose of charging them with lime; the
dotted circles are perforations in the sides of the vessels (furnished with plugs)
for the purpose of ascertaining the depth of the stratum of lime, or other purify-
ing material; and the three tubes q q q at the bottom of the vessels are for dis-
charging the lime when saturated with the various matters that have been
condensed during the purifying process. To aid the complete discharge or
ciearing of these vessels of their contents, three bars of iron are employed as
scrapers, one in each vessel, and a rod, as a handle, is screwed into each, and
passes through a stuffing box in the side of each vessel. We are not aware
whether the preceding apparatus has been adopted in practice. Retorts of a
semicircular form in their transverse section have been tried, but although the
coal was very rapidly and effectually decomposed, they were so speedily
destroyed that we believe retorts of this figure are no longer employed. Upon
the subject of retorts generally, it may be observed, that they, together with
the hydraulic mains, and other necessary connexions, form one of the principal
items of charge in the erection of gas works on the ordinary plan; and that in
conducting works on the same principle, an enormous expense is annually in-
curred by the oxidizing or burning away of the retorts. Indeed the oxidation
of these vessels is so rapid, that however the time of their duration may vary
from a difference of their form, the quality of the iron, or the mode of setting
them in the furnace, they eannot withstand, on an average, more than eight or
nine months' wear. To avoid these sources of expense, and with a view to
other advantages, Mr. S. Broadmeadow, of Abergavenny, devised the following
process, which he secured by patent. The plan was adopted at the Aber-
gavenny Gas Works, but has not come into use elsewhere; and although it may
not realize all the advantages contemplated by the inventor, is deserving of notice
in this place. The plan consists, first, in substituting brick ovens for iron
retorts; secondly, in exhausting the ovens of gas, as fast as it is generated,
by means of an exhausting cylinder, or any equivalent apparatus; and thirdly,
in purifying the gas so generated, either wholly or partially, by admitting into
the gasometer a certain portion of atmospheric air. The engraving on
page 593, with the following description, will sufficiently explain the process;
a is the oven in which the gas is generated; b the oven door; d door of
the fire grate; e a pipe through which the gas is conveyed from the oven
to the condenser f, into which a small hand-pump g is inserted to draw off
the coal tar; h a pipe through which the gas passes from the condenser into
the top of the tº: cylinder i : the piston of this exhausting cylinder
receives its motion from a small steam engine, which is supplied with steam
from a boiler fixed in the flue, and heated by the waste fire of the furnace. k k
two pipes, one leading from the top and the other from the bottom of the ex-
hausting cylinder to the purifier l; m the outlet pipe to convey the gas from
the purifier into the gasometer; and n is a pipe branching from the pipe h to
convey the gas, at the alternate vibration of the beam, into the lower part of
the same cylinder. Some ovens on this principle have, as we have already
mentioned, been erected at the Gas Works at Abergavenny, and it is stated, that,
after being kept constantly at work for two years, they were not apparently the
worse for wear, whilst the charges for repairs had not reached twenty shillings
each per annum. Another advantage is, that as these ovens contain a charge
equal to about six full sized iron retorts, and require to be charged but once
in twenty-four hours, there is not only a saving in the first cost of erection, and
in the annual wear and tear, but in all the daily labour consequent upon the old
GAS LIGHTING. 593
process, in which much time, as well as labour, is usually expended in the
drawing off the charge, and in recharging.
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The next improvement, and which indeed constitutes a principal feature in
Mr. Broadmeadow's invention, is that of his patent application of an exhaust-
ing cylinder, or other apparatus, to exhaust the gas from the condenser, thereby
causing a partial vacuum, and enabling the gas to flow from the ovens as fast
as it is generated. By means of this exhausting apparatus a portion of atmo-
spheric air, equal to about one-eighth part of the entire quantity of gas, is
admitted into the gasometer, when the oxygen of the atmosphere mixing with
the suphuretted hydrogen precipitates the sulphur, and gives to the lighted gas
a greater degree of brilliancy. This mode of purifying gas is said, by the
patentee, to be so efficient, that, when the coal used is of good quality, no other
purifying process is required. As the admission of too great a quantity of
















594 GAS LIGHTING.
atmospheric air would prove injurious, the requisite speed at which the exhauster
should be worked is shown by a water gauge.
We shall now proceed to describe Mr. Ibbetson's patent process of preparing
inflammable gas by decomposing water, in conjunction with coal, in a furnace
of a peculiar construction. . The following engraving represents a vertical
section of the apparatus employed. In the central compartment at a is an
iron door and frame, opening above the fire-place for supplying the fuel thereto;
immediately under the arched top of the fire-place is a small aperture b, for the
admission of the air requisite for the combustion of the fuel; there is another
small door, (shown by dots at c,) for the purpose of lighting the fire; d is the
ash-pit, e e e is the flue which descends, and then takes the course pointed out
by the direction of the arrows to the chimney, thus enveloping the decomposing
chamber, which occupies the space between the flues and the central furnace.
The coals or other substances to be decomposed are introduced through an
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iron door h; this door, as well as the two other doors, l l (shown by dotted lines),
for extracting the coke, are kept closed air tight, by luting, during the process
of distillation; and for clearing out the ashes under the gratings, there are
apertures at i i, fitted also with doors, and kept closed like the last mentioned,
whilst the decomposition is going forward within. The steam is introduced at
two places:in the decomposing chamber; one at f by a pipe of retort earth, from
whence it ascends among the ignited coke, passing round the chamber in the
direction shown by the arrows; the other at k, where a tube of retort earth is
extended across the chambers horizontally, the steam escaping from it through
numerous small holes at the bottoms and sides. The gases and vapours pro-
duced by these combined circumstances make their exit by a pipe at 0. B
this apparatus, the patentee also professes to decompose tar and oil along wº

GAS LIGHTING. 595
the coal; in which case, these fluids would be introduced on the right hand
side, (opposite to k,) through tubes, regulating the quantity by means of
stop-cocks, which quantity should of course never be more than will become
decomposed, whilst circulating through the burning coal, without reaching the
bottom of that side where it enters. The patentee observes, that the coals
should be broken into pieces not exceeding the size of walnuts, before they are
put into the decomposing chamber; and that the charges should be made from
time to time by fresh layers of an inch and a half in thickness, after the pre-
vious charge has become red hot.
We have already stated that Mr. Murdoch experimented upon wood and
peat, as well as pit coal, in order to ascertain the qualities and quantities o
illuminating gas furnished by each. Shortly after the introduction of gas light.
ing into public use, experiments were made upon various other substances,
with the same view ; as coal tar, pitch, pine knots, and sawdust; and in 1815
Mr. John Taylor obtained a patent for an apparatus for the purpose of preparing
inflammable gas from any kind of animal, vegetable, or mineral oil, fat,
bitumen, or resin, which can be rendered fluid by heat. The process may be
briefly described as follows: the liquid material is allowed to flow in a very
minute stream into a retort heated to redness, and containing a quantity of coke,
hard broken bricks, or other porous and refractory substances; here the oil is
º converted into a very fine and brilliant gas, which is conducted to a
close vessel surrounded by water, in order to condense any oil which may have
come over, not decomposed, or in the state of vapour, which oil is returned to
the retort by a very simple arrangement. From the condenser the gas enters
a vessel containing the liquid from which the gas is prepared, by which a
further condensation of any condensible vapour which the gas may contain is
effected, and the gas then passes into the gasometer.
Mr. Philip Taylor some time afterwards obtained a patent for an improved
apparatus for obtaining gas from various substances in a liquid state, a section
of which apparatus is exhibited in the following engraving. When the liquid
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matter introduced into the retort is of easy decompositioi, o, øistiliation of it

596 GAS LIGHTING.
through a single retort will be in general sufficient to separate the gas in a
tolerably pure state; when they are, however, such as to require a longer pro-
cess, the gaseous products of the first distillation are passed into a second retort,
to complete the separation of the contaminating matter. As many as ten
retorts similar to those shown in the engraving may be conveniently arranged
over one furnace. In the case of a single distillation it is therefore to be
understood that these are all supplied at once with the fluid matter, and the
product of each retort respectively is carried from them direct to the gas holder;
but when a second distillation is necessary, the ten retorts before mentioned
would be employed as five pair, and the diagram is drawn so as to show the
operation either by a single or by a pair of retorts, which we shall now explain.
The figure gives a vertical section of two cast-iron retorts, a and b, fixed over a
furnace constructed with fire-bricks; the retorts are about four feet long, of a
cylindrical form, with covers accurately fitting their necks so as to render the
vessels air-tight, when they are luted on and fastened down with keys or screws.
They are placed erect in the brickwork by resting on their projecting flanges,
leaving open spaces around them as at e c c, by which very extended surfaces
are exposed to the direct action of the fire. Within each of the retorts a casing
or shell of wrought iron is placed, exactly fitting the interior; these are filled
with fragments of brick or coke, &c. and as these materials require to be fre-
quently changed, each case is provided with ears or lugs, for the convenience of
drawing them out, or letting them down into the cast-iron retorts. Vertical
tubes, e.g., are placed in the centre of each retort; they are connected at their
upper ends by the horizontal tube f and, passing through the covers, their other
ends descend to the bottom of the retorts, when they are perforated with holes,
as shown in the figure. The internal cases, previously empty, are then filled
with broken bricks or other substances before mentioned, and the covers and
joints being all properly luted and secured, the retorts are exposed to the action
of the fire until the material contained in them acquire a red heat. Thus pre-
pared for operation, the fluid to be distilled is allowed to flow through the pipe
d in a small quantity into the retort a , here, falling upon the red hot materials,
the process of decomposition commences, which is assisted by the filtration of
the liquid through these substances. Having arrived at the bottom, the gaseous
portion, passing through the perforations, rises up the tube e : thence, pro-
ceeding along the branch f, it descends into the second retort b, by the pipeg,
and passing out again through the holes at the bottom of g, the gas reascends
among the ignited materials, being purified in its progress, until it arrives at the
tube h, which conducts it to the gasholder. When the operation consists of
only a single distillation, the fluid is introduced by a pipe i, shown by the
dotted lines. In this case the tube g does not extend higher than the cap of
the retort, in the centre of which the pipe enters, and passes down the middle
of the tube g, within six inches of the bottom; from thence the liquid, flowing
through the perforations among the red hot materials, becomes quickly decom-
posed, and the resulting gas, filtering as it ascends, reaches in nearly a pure
state, the tube h, which, as in the former case, conducts it to the gasholder.
Coal tar has already been noticed as one of the products resulting from the
distillation of coal, and at the first establishment of public gas works, great
Fº were expected to be realized from the sale of this article; but from the
arge quantities produced, and from its inapplicability to most of the purposes
for which vegetable tar is employed, it was soon found difficult to find a market,
and it became an object to utilize the material by converting it into gas. For
this purpose various processes were resorted to, nearly resembling that just
described, for converting oil and other liquid matters into gas; but a serious
inconvenience was found to result from the deposition of asphaltum in the pipes,
(owing to the imperfect decomposition of the tar,) which quickly choked them
up, and rendered them unserviceable, whilst the gas afforded but a feeble light,
and emitted much smoke... Numerous plans have since been proposed for the
remedy of these evils, of which we shall only notice the invention of Messrs. Were
and Crane; the apparatus, it is stated in the specification, is also applicable to
the distillation of all animal or vegetable solid or liquid matters, from which
GAS LIGHTING.. " 597
carburetted hydrogen may be obtained. The process consists in introducing into
the retort a constant stream of water, or a current of steam into the exit pipe,
which, mixing with the volatile matters arising from the substance under
decomposition, causes them to fall down again into the retort without proceeding
further to choke up the pipe, while the more gaseous products pass on through
the steam in a purer state to their destination, to be afterwards treated in
the usual way. Fig. 1 is a front elevation of the improved retort set in the
brickwork of the furnace; and Fig. 2 is a vertical section of the same ; the
Fº §
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* *
letters have a reference to the same parts in each figure, a is the ash-pit, h
the furnace, c c the flue winding round the retort; d the retort, with its lid
fastened in the usual way by a cross bar and screw; e the exit pipe, through
which the gas escapes as it is generated; f is a wrought-iron pan or tray, to
hold tar or other liquid matter to be distilled; g a supply pipe to f leading
from the cistern or reservoir h; i is a water pipe, and k a cistern of water.

4 q
598 GAS LIGHTING,
When tar, for instance, is to be operated upon, the retort, partly filled with coke
or broken bricks, is to be brought to a bright red heat, which may be ascertained
by inspection through the holes o o, shown in Fig. 1, which are provided with
stoppers; the cock of the water pipe is then opened, to admit the water to flow
in a slender stream into the retort, the heat of which immediately converts it
into vapour. This done, tar is to be admitted from the reservoir h to flow
through the pipeg into the pan f, where it is quickly decomposed; the gas, as
it ascends, enters the exit pipe, and necessarily passes through a large volume
of steam, which, the patentees state, causes an instant precipitation of the car-
bonaceous matters, which would otherwise lodge in the pipes, and ultimately
obstruct the passage of the gas through them. The gas thus relieved in the
earliest stage from the principal contaminating matters, has then to pass
through the ordinary purifications, by which it is ultimately delivered to the
burners, in a state of great purity, for consumption. When coal or other solid
matters are to be decomposed to obtain the gas, the pan f, the pipe g, and the
reservoir h, are to be removed, and the operation conducted without them,
retaining however the use of a current of steam as before.
The subjoined engraving represents Mr. Gordon's portable gas lamp. The
idea of employing gas as a substitute for lamps and candles, occurred to
Mr. Murdoch, as we have seen, so early as the year 1792, when he made
some experiments with that view, but seems to have subsequently aban-
doned the idea ; but to Mr. Gordon is due the merit of realising it, and
thus at length rendering inflammable gas applicable to every purpose of arti-
ficial illumination. These lamps consist of strong wrought-iron vessels of
various dimensions and forms, in which the gas is compressed into one thirtieth
of its bulk at the ordinary atmospheric pressure; the flow of the gas being
regulated with the utmost exactness, according to the degree of light required,
by a valve, which we shall subsequently describe.
A company having been formed to carry Mr. Gordon's invention into effect
upon an extensive scale, works have been established in London, and at some
of the principal country towns, at which the gas is manufactured; and the lamps
being charged therewith, are furnished to the consumer as occasion requires.
The gas with which the lamps are charged is usually procured from oil, on
account of its greater purity, and of its occupying less space than coal gas, one
foot of oil gas being equivalent in illuminating powers to nearly three feet of
coal gas. The gas is generated by the usual processes, and the following en-
graving represents the apparatus employed at the London Portable Gas Works
for charging the lamps; a is the main horizontal shaft of a steam engine, upon

GAS LIGHTING. 599
which are fixed two spur wheels b b ; the teeth of these take into the teeth of
two similar wheels c c fixed on the axis of a three-throw crank, to which is
thereby communicated a rotatory motion. The crank imparts (in the usual
manner) an alternating motion to the rods e ee, which work three force pumps:
for a description of the forcing pumps originally employed for this purpose,
(which were of a singularly ingenious construction, although we believe they
have since been replaced by others more nearly resembling the ordinary
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force pump,) we refer the reader to the article AIR PUMP. As the plunger of
each pump is successively raised, a quantity of gas equal to the space pre-
viously occupied by the plunger flows from the gasholder into the chamber at
the opposite end, by means of a pipe of communication, part of which is
brought into view at f. The valve by which the gas enters, opens inward, so
that it cannot return the way it came ; but there is another valve which opens






600 GAS LIGHTING.
outward, and this is kept closed by a spring of sufficient power to prevent the
escape of the gas in the uncompressed state; upon the descent of the plunger
the strength of this spring is overcome, the gas is forced out, and the valve
closes again. . From the pumps the gas proceeds along the tube g, and enters
by the jointed valve h, into a strong wrought iron recipient i ; in this vessel it
is evident the gas might be collected and condensed to any required number of
atmospheres; but the valve j being opened (by the cross-handled key shown),
the gas is suffered to flow through the pipe k k, which is extended along the
upper side of the “filling table” m, and from thence into the reservoirs (“port-
able lamps”) llll, by which arrangement the pressure of the gas becomes
equalized in all the vessels, however great their number. The degree of con-
densation at which the gas has arrived by the continued action of the pumps, is
shown throughout the process by a mercurial guage, applied in the following
manner. The pipe n, which proceeds from the recipient i, conveys the gas
under compression into the reservoir of mercury, at the bottom of the guage
o of the pressure of the gas upon the surface of the mercury causes the latter
to rise in a long glass tube, hermetically sealed at top, and inclosing a portion
of atmospheric air above the surface of the mercury; this air becomes com-
pressed into a smaller space by the rise of the mercury, as the condensation of
the gas advances, and the diminution of its volume indicates, upon a scale
attached to the tube, the degree of condensation or pressure in the lamps; and
when the mercury arrives at the line denoting thirty atmospheres, the valve j is
shut by means of the cross handle. All the lamps attached to the pipe in con-
nexion with the closed valve being now filled, are taken away by unscrewing them
from the sockets in the tube. The external pressure being removed by turning
off the gas, the lower valves of the lamps close by the pressure of the gas
within them, and the contents are further secured from escaping by a workman
screwing a cap over the lower valve as he successively removes each of them
from the tube. To ascertain whether there is any leakage, the lamps are im-
mersed one by one in a contiguous trough of water, where, if any leakage
exists, it is immediately shown by the gas bubbling up. The perfect state of
each lamp being thus ascertained, they are arranged in extensive racks or
stands, ready to be taken out to the consumers by the Company's carts, which
are regularly dispatched to all parts of the town.
To complete the subject, we shall proceed to describe the construction of these
valves, of the uses of which we have only yet spoken : they are of three kinds,
and were the subject of a patent granted to Mr. Gordon.
The annexed engraving gives a sectional view of an improved stop-valve
(similar to those attached to the principal
recipient i), especially adapted for transfer-
ring the compressed gas from one vessel to
another, without occasioning loss during the
process. It is composed of two pieces of
metal, A and B, which are screwed together º
with a soft metal collar between them at a º \\\\\\\\\
a ; e e represents the openings through
which the gas is allowed to pass. The piece i. § {
A has the regulating steel screw c tapped Nº.
through it, being formed at the lower part | ||
with a double cone, one part of which cone is ||
adapted to fit correctly into the cavity in the
under side of the piece A. Now when the is º
lower cone of the regulating steel screw is
screwed or forced tight down into the conical
seat in the piece B, it prevents all escape of .
the gas; and when it is desired to transfer
compressed gas from one lamp or reservoir to
another, the regulating screw c is to be turned -
until its upper cone fits and applies correctly into the conical cavity of the piece
A, and thereby prevents all escape of the gas up the threads of the regulating

GAS LIGHTING. 601
screw during the process of transferring, allowing, at the same time, free pas-
sage of the gas from one reservoir to another, through the openings e e.
The next valve to be described is the one
which is fixed at the bottom of each reservoir
or lamp, for the purpose of filling them in the
manner described in the preceding part of our
subject; the annexed cut represents a sec-
tion of one of those valves. This filling valve
consists of a small conical plug g, which is
T.
fitted into a conical cavity or seat in the piece i
of metal c, similar to the valves of an air-gun, º is
being closed by a slight steel spring h, and §N jº §.
guided in its way by a metal pin, which slides \ §: §
through a hole in a small brass cap or per- §i. º
forated cover i, represented as screwed over § º
it; d shows a brass plug, which is intended to ... Tº Tri-----rºy
be screwed into the lower aperture of the -: Ž
# , ºff
W
piece c, after the filling is completed. The
upper surface of this screw-plug is furnished
with a soft metal ring or collar, b b (as in the
before-mentioned valve), which being pressed,
by the force of the screw, into contact with the under side of the piece c, effec-
tually prevents any escape of the gas from that end of the reservoir, even if
the filling valve g should not be quite air-tight.
The following figure represents a section of the third and last of these valves,
and its use is to permit the flow of gas to the burner to be regulated with great
nicety and precision. The passages for the
gas, ee, are drilled out of one solid piece of & ſºvº
metal, and the regulating screw c is tapped *
into the side of the same piece; the lower part sº
of it is adapted to screw into an lº at j
one end # the reservoir of the lamp, when š= |||ſil |-
the regulating steel screw c is screwed up so §§
that º.# end fits tightly into the º a
cavity,–it closes it perfectly, and prevents all
escape of gas to the burner a ; but on turning § N sº
the regulating screw slightly round by its -
square head, the gas escapes through the pas-
sages e e to the burner, in any degree that may be desired. Previously to in-
serting the regulating screw, it is dipped into a mixture of bees' wax and oil,
which fills up every minute cavity or space which may be left between the
threads of the two screws.
The engraving on page 602 represents a contrivance for delivering gas to the
consumers in its natural volume, under atmospheric pressure. It consists of a
collapsing gasholder, capable of containing upwards of 1000 cubic feet of gas;
it is mounted on wheels; and being charged at the gas works, the gas is con-
veyed wherever required. The invention forms the subject of, a patent to
Messrs. Coles and Nicholson, and is, we believe, made use of by the Portable Gas
Company at Manchester, in addition to the gas-condensing apparatus erected at
their works at that place. Fig. 1 represents a plan of the cart, with the top of it
removed; Fig. 2 is a side elevation, and Fig. 3 a front elevation; Fig. 4 is
merely an enlarged section of the box marked d in Fig. 2. The recipient is
composed of two distinct parts or halves, a and b; the upper part a is made of
some flexible material, impervious to gas; and the lower part b of some com-
paratively stiff and inflexible substance; when the vessel is empty, the part a,
turning itself inside out, falls down inside of b; the vessel is filled by forcing
the gas from the works through a pipe, which is screwed into a nozle at f pro-
vided with a stop-cock, which is turned off after the recipient is fully inflated,
and the supply pipe from the works removed. The machine then travels
through the streets, and stopping at a customer's door, one end of a flexible













602 GAS LIGHTING.
pipe is screwed into the gasholder of the house, and the other end into a nozle
in the box d, which communicates with the interior of the recipient by means
of intermediate valves shown at Fig. 4. The gas-exhauster c is then put in
motion by the handle at the top, and at every exhausting stroke is filled with
|
|
|
|
|
|
. |
|
|
|
Fig. 3.
gas from the gas cart through the valve g, Fig. 4; and at each forcing stroke,
the gas is discharged through the valve h, and along the flexible pipe into the
gasholder of the house, until the required quantity is transferred. The gas cart
thus proceeds from house to house, until the whole load is discharged. Along
the bottom of the cart is a pipe e, connected at one end with the stop-cock j.
and at the other with the box d of the exhauster, and perforated with nume-
rous small holes, for the purpose of allowing the passage of the gas along the
bottom of the cart when the flexible top lies over it. Since the foregoing
account of the Portable Gas Machinery was prepared for the press, we have
been informed that it has been nearly superseded by subsequent improvements
in the manufacture and management of coal gas; nevertheless, the subject pos-
sesses sufficient intrinsic merit for our pages, as much of the mechanism is
applicable to other purposes.
The “Domestic Gas Apparatus,” shown in the following engraving, is an


























GAS LIGHTING. 603
invention of Mr. Pinkus, for the manufacture of gas on so small a scale as to
be adapted to private houses. An apparatus of the kind was exhibited in use
; : -------------
#ssssss Sºs
Pig. 4.
Fig. 5.
=sº**.*.*.*.*.*
f
s
-
|§
E
§
-|:i.|:
º
:
s|N
f
É
!t--*-
;:És
-.--º:*
..-- -•.
s
--
*
|
ñº, - -W
E
H
§§
jºis;
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intº -
T=
㺠#: jº,
for a considerable time in the Strand, and we believe the invention has been
adopted in various extensive private establishments and small manufactories.
*ig. 1 is a front elevation; Fig. 2 a lateral section of the apparatus; Fig. 3 a
section of the retort; and Fig. 4 a section of a retort of a different construc-































604 GAS LIGHTING
tion; Fig. 5 is a section of the condenser. In each bottom figure the same
letters refer to the same parts. a, Figs. 1 and 2, shows its application to a
kitchen range, but it is equally adapted to any other common fire-place; b b,
Fig. 2, is a recess or furnace built in brick at the back of the fire-place, covered
in front by an iron plate c, and having a flue d opening into the chimney; e,
Figs. 1, 2, and 3, is a cylindrical retort, divided by two or more internal par-
titions, radiating from a conical pipe f as shown in Fig. 3. The retort is turned
with a small rim or flange at the fore end, which fits into the plate c, and the
hinder end is supported by a stout pin projecting frcm the back of the retort,
and resting in an iron socket let into the brickwork. The hinder end of the
pipe f terminates in a cup or cavity g, pierced with several holes, and serving
as a chamber for the gas to collect in ; the pipe f is also pierced with numerous
small holes, to allow the tar, as it forms, to fall through them upon the burning
fuel, where it, as well as that portion which runs down the conical pipe f and
the cup g, is decomposed and converted into gas. In the fore end of the pipe
f is screwed a stuffing box, through which passes the pipe h, leading to the con-
denser. Each compartment of the retort has a door or mouth-piece m m, by
which the coal or other material for making gas is introduced, and the door is
secured by screws, the joints being either ground true or luted; n is an iron
plate, sliding in grooves, and, when lowered down, serving to defend the face of
the retort and the pipe h from the action of the fire. Fig. 5 is a vessel divided
into two parts, the lower part o, which is air tight, containing a quantity of tar,
into which the pipe h dips a few inches; it is supplied with tar from another
vessel p, by means of a bent pipe g; r is a pipe for drawing off the tar when
required, and s an opening by which the tar runs down the pipe k into h, and
thence into the retort. The upper division of Fig. 5 contains a range of bent
pipes t t surrounded by water, one end of which, v, opens into o, and the other
end, w, leads to the gasometer; from the lower bends of these pipes short pieces
y y descends into the tar in o, by which means the tar condensed in the
pipes t t descends into o, whilst the gas cannot escape through the short
pipes. The operation is as follows:–the retort being charged, and the doors
secured, the retort is turned till the chambers are in the position shown in Figs.
1 and 3; the shutter n is then let down and the fire lighted, a portion of the
heat and flame from which passes through an aperture in the back of the
range (shown by the black space between the bars in Fig. 1,) into the furnace
b, causing, in a short time, the lower part of the retort to become red hot, and
the coals or other materials in the interior to give out gas, which, collecting in
the chamberg, passes through the pipes f and h to the condenser; at the same
time the tar given out by the coals in the upper chambers of the retort,
descends through f and g on to the burning fuel in the lower chamber, and
becomes decomposed. When it is supposed that the materials in the lower
compartment have given out all the gas contained in them, the retort is turned
j round, so as to bring another compartment immediately over the flame,
when the gas is again given out as before. The gas thus formed contains tar
and other impurities, from some of which it can be freed by a reduction of tem-
perature; the pipe h is therefore made to dip a few inches into the tar vessel o,
and through this tar the gas has to rise to enter the condenser, by which means
it is divested of a portion of its impurities, and, upon entering the condenser,
it passes through a great length of pipe surrounded by cold water, when all the
condensable impurities are separated, and descend into the tar vessel by the
pipes y y. The tar, as we have before stated, returns to the retort by the F.
k and h, and is decomposed by falling on the burning coke in the retort. From
the condenser the gas passes to the purifier, and thence to the gasholder; but
the method of purifying the gas, either upon a large or a small scale, forms the
subject of a separate patent to Mr. Pinkus, which we shall now proceed to de-
scribe, observing only that Fig. 4, in the preceding engraving, merely repre-
sents an oblong retort, which may be substituted for the one before described,
when the length of the fire-place will admit of it; it will then of course be
fixed, instead of turning upon a pivot, and the gas will pass off by the pipe h;
and the tar return by k, inserted in the top of the retort.
GAS LIGHTING. 605
The purifying substances employed by Mr. Pinkus, are the chlorides of soda
or of lime. The following engraving represents two arrangements of the
purifying vessels; the one adapted to the use of gas works on a large scale,
and the other for the use of private houses, to ºff, the gas as it passes from
the public main to the burners. The method is as follows: the gas, upon
leaving the condenser, passes through a solution of the chlorides of soda or of
lime, which may be contained in a vessel resembling that shown in section at
Fig. 1, through which the gas may be made to pass, acting under a pressure
Fig. 2.
E
==
... --~~
- ää #: -
l Hill
º
of from ten to twenty inches of water, by which means it will be purified, and
its obnoxious odour and bad smell removed; in addition, the patentee recom-
mends to pour a quantity of the same solution into the feeder A, Fig. 2, from
whence it flows into the tar vessel b b b, through the bent tube c. In this
vessel, (which communicates with the retort by the pipe d') the solution will mix


4 H
606 GAS LIGHTING.
with the condensed matter that falls into it through the branch pipes connect-
ing the refrigerator tubes fff, (which are immersed in a vessel of water gg,)
with the tar vessel. The compound thus formed, and kept agitated by the gas
issuing from the dip pipe h h, is made to flow in a small stream through the
pipe d, into the retort, while in action; upon coming in contact with the ignited
materials within the retort, other vapours or gases will be generated, which,
combining or mixing with the carburetted hydrogen gas, a chemical action will
take place, whereby the gas, while in the retort and during its passage through
the refrigerator, will become partly purified, or will be so altered as to be more
easily acted upon in its passage through the solution of the chloride of lime,
when its purification will be finished. In preparing the solution, the patentee
directs to employ one part of chloride to about thirty-five parts of water, and
when the chloride is in *..." concentrated state a diluted acid, sulphuric or
muriatic, may be added tº the solution to assist the liberation of the chlorine
gas from the lime; and the quantity of water may then be increased to forty or
fifty parts, with one of the chloride. Fig. 3 represents the apparatus for the
more perfect purification of the gas on its passage from the street mains to the
burners, i is a recipient, intended to contain and supply the purifying liquid;
this vessel is connected with another vessel k by a syphon or by a bent tube l,
inserted through the centre and top of the lower vessel k, and having a stop-
cock m. The lower vessel k is made gas tight, and formed of tin, copper, or
sheet iron, and is a receptacle for gas, which flows through it, and for the
purifying liquid that falls from the upper vesel i ; n is a common sponge placed
on a shelf of coarse wire gauze of p is a manhole made in the side of the vessel
AE, sufficiently large to admit the hand and sponge; q is a pipe leading the gas
from the main; and r is another pipe to supply the gas in a purified state to the
burners; s is a waste pipe to let off the liquid when it has become too much
impregnated with the impurities of the gas; and t is a washing pipe leading
from a cistern; u and v are stop cocks for admitting and drawing off the liquid.
The operation of this apparatus is as follows: into the recipient i pour a mix-
ture of one measure of the concentrated liquor of the chloride of lime, diluted
with from twenty-five to thirty measures of water. When gas is required to
supply the burners, turn on at the same time the stop-cocks m, in the bent tube
l, and the leading pipe q; the purifying liquid will then flow through the bent
tube l, on to the sponge n, which will absorb a portion sufficient to keep it
always wet, and will permit the liquid to filter through, and fall to the bottom
of the vessel k; at the same time the gas will continue rising through the
moistened sponge n, where it will be acted upon by the purifying liquor, and
its obnoxious odour will be removed before it arrives at the burners through the
supply pipe r.
One object of great convenience and utility to which gas lighting has
within these few years been applied, is the illumination of public clocks. This
we believe was first put in practice at Glasgow, where a clock with two faces,
supported at the extremity of a projecting bracket, was lighted by jets placed
above it, the light of which was reflected on each face from mirrors placed
within the wings of an elegant representation of a phoenix, which sur-
mounted the clock. In order to light the burner without sending up a per-
son for that purpose, in addition to the pipe which supplied it with gas, was
another extending from the main to the burner, having a stop-cock at its
junction with the main, and being perforated with numerous small holes
throughout its length. Upon opening the cocks, the gas flowed through both
pipes, and issued at the small holes in the flash pipe as it was called; and a light
being applied below, quickly communicated along the whole length of the
flash-pipe, and upon reaching the jet, ignited the gas issuing from it; after
which, the cock on the flash pipe was shut. Various methods have since been
proposed of lighting up clocks, one of which is as follows: a dial plate, out of
which the figures representing the hours are cut, in contrary succession to the
usual representation of them, is made to revolve on the axis that would other-
wise receive the hour hand. Behind it is a solid field, out of which a sufficient
space is cut to show the hour, half hour, or quarter; each half hour is repre-
GAS LIGHTING. 607
sented by a star, and each quarter by a dot; and the time is reckoned by the
hours and quarters which have passed the centre of the opening Behind the
revolving plate is placed a gas light, which is ignited by the jet of gas being
directed on to a piece of spongy platina.
A somewhat superior method to the preceding is exhibited in the following
engraving. A is the dial plate of a common clock, with the hours, &c.
marked upon it, as usual; B is the proposed addition to it, for the purpose of
exhibiting the time distinctly during the night; C is a light cog-wheel, placed
immediately behind the day dial; having its centre fitted in the arbour of the
hour hand, and revolving with it. The
night dial B is designed to be made of
plate glass, with the hours painted upon
it in black, and to revolve on an axis in
its centre. The index represented by
an arrow is fixed. The periphery of
the glass plate is encompassed by a rim
of brass, having cogs in its outer edge,
which fits into the cogs of the wheel C;
consequently they move together, and
being of equal diameters, they perform
their revolutions in equal time. The
time represented in our engraving, is a
quarter past X; when the hour hand
has moved on to XI. (for instance), the
transparent dial B will have moved an
equal space past the fixed index, and
denote the same precise time. Both
dials must, by this simple contrivance,
invariably agree in their respective indi-
cations of the time. During the day,
the time is observed on the large dial as usual; and at night a lighted lamp
placed behind the transparent dial will always exhibit the time as distinctly.
But the most perfect and ingenious mode of illuminating public clocks which
has come under our notice, is that by which several of the church clocks in
London are lighted. By the revolution of the hands, and the addition of only
one wheel and pinion to the clock, the gas is lighted and extinguished at regular
stated hours, which hours may be varied monthly to suit the increase or decrease
in the length of daylight, by simply adding or withdrawing a pin. . The
inventor is Mr. Paine, from whose account in the Transactions of the Society of
Arts we have taken the following abbreviated description.
Reference to the Engraving.—Fig. 1 represents a skeleton frame dial, cast all
in one piece; the eight central divisions are very thin, and curved, so as not
to coincide or interfere with the hands while passing over them ; the spaces are
all filled up with transparent red glass, ground rough on the inside. This by day
is sufficiently dark to relieve and render distinctly visible the gilt hour numbers;


6()8 GAS LIGHTING.
but at night, when the gas burners behind the dial plate are lighted up, the
hours, minutes, and hands appear black, and the rest of the dial glows with 3.
dusky red light. Fig. 2 is a horizontal section across the aperture a q in the
church tower at the back of the dial b b, c the tube which carries the hour
hand, having a balance weight and the wheel 48 on its inner end; through
this passes the shaft d d, holding at one end the minute hand, and at the other
end the pinion 14 and balance weight e : fiftwo gas burners; g g the tubes
supplying the gas; the aperture a a, not being so large as the dial, is cham-
ferred off at i i, to give a clear passage from the lights all over the dial; jj a
curved reflector, made of sheets of tin; k k a bar crossing the aperture a a
within, to support the motion wheels, and the additional twenty-four-hour
wheel, 96; the long axis d d receives motion from the clock (as usual) by a
bevel wheel; 14, 42, 12, and 48, Fig. 3, are the usual motion wheels and
Fig. 1. ºrwºrrºr- - 21 Fig. 2.
ST
Tºl
&
Á
S.
22:22-2
pinions; an additional pinion of 12 is put on the wheel 42, to turn the wheel
96; this has thirteen pins, one hour's motion apart; these pins raise up the
weighted lever l, in Fig. 3, and let it drop; while this is up, (as shown by the
dotted lines,) its opposite end m, by means of the connecting rod n, keeps the
lever handle o of the gas cock p down, and thus nearly closes it, allowing the
passage of only just enough gas to keep the burners alight; but at eight o'clock,
when the weight l drops, it raises the handle o and quite opens the cock p,
by which the dial is instantly illuminated. Thus, Fig. 3 represents the lever !
down, and the pins nearly beginning to raise it; by removing two pins, one at
each end, the clock will open the gas-cock one hour sooner, and nearly close it
one hour later. By successively removing the pins as the days shorten, and
replacing them as the days lengthen, the clock is accommodated to all seasons.
The whole space is kept clear between the lights and the dial, except only the



GAS LIGHTING. 609
axis e, Fig. 2; and the lights being placed on each side of this, and having a
large reflector, no shadow is perceived from it.
With respect to the quantity of gas obtainable from a given weight of coal,
it depends greatly upon the quality of the coal, and also upon the construction
of the retorts, and the method of working them. Mr. Peckston, in his valuable
treatise on gas lighting, whilst writing on this branch of the subject, observes that
pit coal may be divided into three classes, according to the proportions of its
component parts. Such coals as are chiefly composed of bitumen are to be
considered as belonging to the first class. These coals burn with a bright
yellowish blaze during the whole process of combustion; they do not cake,
neither do they produce cinders, but are reduced to white ashes. At the head
of this class is to be placed Cannel coal; and most of the varieties of Scotch
coal, as well as some of those found in Durham and Northumberland, belong to
it, likewise the coals from Lancashire and the north-western coasts of England.
When ellipsoidal retorts are used, (which is the form which Mr. Peckston
decidedly prefers,) and charged with 13 bushel, or about 126lbs of coal, the fol-
lowing quantities of gas may be obtained in the manufactory, or on the large
scale. From a ton of
Lancashire Cannel ... . . . . . . . 11,600 cubic feet of gas.
Newcastle (Hartley's) . . . . . . . 9,600 32
Staffordshire (best kind) . . . . . . 6,400 33
The coke obtained from coals of this class is in small quantity, and of very
inferior quality. The second class of coals comprehends those varieties which
cake in burning. These contain less bitumen and more charcoal than the first
class. They produce less ashes, but afford hard grey cinders, which when
burnt over again with fresh coals, produce a very strong heat. The gas obtained
from these coals is not of so rich a quality as that from the first class, but the coke
is extremely well adapted for domestic and culinary purposes. When ellipsoidal
retorts are used, charged as before, with about a bushel and a half, from a
ton of
Wallsend, may be obtained . . 10,300 cubic feet of gas.
Temple Main . . . . . . . 8,100 95
Primrose Main. . . . . . . 6,200 99
Pembry . . . . . . . . . 4,200 39
The third class of coal consists of such as are chiefly composed of charcoal,
chemically combined with different earths, and containing little or no bitumen.
Amongst the varieties of this coal are the Kilkenny coal, the Welch coal, and
the stone coal. None of the coals comprised in this class can be profitably
used for making gas.
Mr. Peckston gives the following table, exhibiting the comparative quantity
of gas obtainable from the following different species of coals comprehended
in the first and second classes, the Scotch Cannel coal being considered the
standard, and estimated at 1000.
Scotch Cannel. . . . . 1000 Temple Main . . . . 690
Lancashire ditto . . . . 986 | Manor Wallsend . . 650
Yorkshire ditto . . . . 949 || Forest of Dean—Middle
Bewicke and Craister's Delf . . . . . . 612
Wallsend . . . . . 875 | Eden Main . . . . . 562
Russell's ditto . . . . . 861 | Staffordshire coal, 1st kind 546
Tanfield Moor. . . . . 850 i Ditto ditto, 2d ditto 514
Heaton Main . . . . . 822 | Ditto ditto, 3d ditto 492
Hartley's . . . . . . 810 | Ditto ditto, 4th ditto 490
Killingworth Main . . . 792 | Pembry . . . .354
Pontops. . . . . . . 762
With respect to the best form of retorts, and the mode of working them, so
as to produce the largest quantity of gas, we give the following summary of
three sets of experiments detailed in Mr. Peckston's work; the coals in each
instance were of the same quality. 103 chaldron 12 bushels, distilled in
61 () GAS ENGINE.
circular retorts, charged with 2 bushels of coals, and each charge worked off in
6 hours, afforded 8300 cubic feet of gas per chaldron, and required 43 chaldron
14 bushels of coals for heating the retorts, = 42 per cent. on the quantity
employed for making gas. By cylindrical retorts charged with 2 bushels at
each charge, and which was worked off in 8 hours, 85 chaldron, 27 bushels
of coals yielded 10,000 cubic feet of gas per chaldron, and required for car-
bonization or heating of the retorts 21 chaldrons 16 bushels of coals, or about
25 per cent of the quantity carbonized. With ellipsoidal retorts, the two
diameters of which were 20 inches and 10 inches respectively, charged with 13
bushel, and each charge worked off in hours, 61 chaldron 8 bushels of coals
yielded 14,000 cubic feet of gas per chaldron, and required for carbonization 19
chaldrons 27 bushels of coals, or 32 per cent. of the quantity carbonized. Mr.
Peckston likewise states that five elliptical retorts are capable of carbonizing
45 bushels, or 33 cwt of coals, in 24 hours, but their average work may be
taken at 1 chaldron, or 27 cwt. in that time.
Mr. Anderson, of Perth; made a great number of experiments, to determine
the comparative quantity of light afforded by candles and coal gas; the size of
the candles which he employed, was short sixes. The following are some of
the results:—
A 3-jet burner consumed per hour 2,074 cub. in. = 6 candles.
An Argand of 5 holes 33 2,592 , 8 :,
Ditto 10 93 - 3 y 3,798 39 12 95
Ditto 14 , 3 y 5,940 ,, 19%. ,
Ditto 18 ,, 33 6,840 , 21 ,
The mean of these results is, that 324 cubic inches of coal gas yield light
equal to that of one candle for an hour; but this is the coal gas of Perth, the
specific gravity of which, Mr. Anderson says, is 650.
GAS ENGINE. An engine in which the motive force is derived from the
alternate expansion and condensation of the liquefiable gases. For the discovery
that certain gases may be reduced to the liquid form, and for the suggestion of
such gases as prime movers of machinery, we are indebted, (as we have
already noticed under the word GAs,) to Sir Humphrey Davy and Mr.
Faraday. The important advantages which seemed likely to be realized by
this discovery, naturally attracted the attention of engineers and scientific
mechanists, and many of the most eminent occupied themselves in endeavour-
ing to devise such arrangements as would render it applicable in practice.
The person who pursued the subject with the greatest perseverance was Mr.
Brunel, who obtained a patent for an apparatus, in which the liquefiable gases
are employed to furnish the moving power, and more especially the carbonic
acid gas. This gas may be obtained by decomposing any of the carbonates
by the action of the common acids. The mode of obtaining the liquid from
the gas is by forming the gas under a gasometer, and condensing it afterwards
in another vessel by means of a condensing pump, and continuing the opera-
tion until it passes to the liquid state.
The engraving on the next page represents Mr. Brunel's apparatus. This
apparatus, as shown at Fig. 2, consists of five distinct cylindrical vessels; the
two exterior vessels a and b contain the carbonic acid, reduced to the liquid form,
and are called the receivers; from these, it passes into the two adjoining vessels
c and d, termed expansion vessels; these last having tubes of communication
with the working cylinder e, the piston therein (shown by dots) is operated upon
by the alternate expansion and condensation of the gas giving motion to the
rod f, and consequently to whatever machinery may be attached thereto. As
the working cylinder e is of the usual construction, no further description of
that part of the apparatus is necessary; and as the two vessels on one side of
the cylinder are precisely similar to those on the other, a description of the
receiver a and the expansion vessel c will apply to their counterparts b and
d; the two former (a and c) are therefore given in a separate Fig. 1 on a
larger scale, in section, that their construction may be seen, and their operation
better understood. The same letters of reference designate the like parts in
both figures. The communication of the condensing pump (before mentioned)
GAS ENGINE.
611
, which can be stopped at pleasure
by the plug or stop-cock h. When the receiver has been charged with the
with the receiver a, is through the orifice g
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612 GAS WACUUM ENGINE.
prevent the absorption which would otherwise be occasioned by the thick sub-
stance of the metal. The expansion vessel is connected through a pipe m to
the working cylinder e, these vessels contain oil, or any other suitable fluid
shown at n, as a medium between the gas and the piston. The receiver is
a strong gun metal vessel, of considerable thickness, in the interior of which
are placed several copper tubes, as represented at o o o, the joints of these
tubes through the top and bottom of the receiver are made perfectly tight by
packing. The use of these tubes is to apply alternately heat and cold to
the liquid contained in the receiver, without altering very sensibly the tem-
perature of the cylinder. . The operation of heating and cooling through
the thin tubes o o o may be effected with warm water, steam, or any other
heating medium; and cold water, or any other cooling medium. For this
purpose, the tubes o o o are united by a chamber and cock p p, by the opening
of which, with the pipes o o, hot and cold water may be alternately let in
and forced through by means of pumps, the cocks being worked in a similar
manner to those in steam engines. Now if hot water, say at 1200, be let in
through the tubes of the receiver a, and cold water at the same time through
the receiver b, the liquid in the first receiver will operate with a force of about
90 atmospheres, while the liquid in the receiver b will only exert a force of 40
or 50 atmospheres. The difference between these two pressures will therefore
be the acting power, which through the medium of the oil will operate upon
the piston in the working cylinder. . It is easy to comprehend that by letting
hot water through the receiver b, and cold water through the opposite one a, a
re-action will take place, which will produce in the working cylinder e an
alternate movement of the piston, applicable by the rod f to various mechani-
cal purposes, as may be required. It is to be observed, that the use of the
gasometer, and of the forcing, pumps, is simply for obtaining the gas, and
for charging the receivers with the liquid. When the receiver is once
charged, and has been closed with the stop-cock h, the gasometer and forcing
pumps are to be disconnected from the receiver by unscrewing the pipe à at the
joint. The same pipe may however be used as the means of connecting the
receiver with the expansion vessel; the adoption of two distinct pipes for these
purposes is intentionally avoided, as it would become necessary in consequence
to have two orifices as well as two stop-cocks. It is obvious that no difficulty
exists in connecting the forcing pump with both receivers, as the small pipes
used for that purpose may be made to reach either.
Several years have elapsed since the engine just described was patented, but
hitherto no machine upon the same principle has been brought into operation;
and as the mechanical talents of Mr. Brunel are unquestionable, and as he is
known to have devoted much time to bring the invention to perfection, it is
probable that the cause of the want of success lies in the principle itself, and that
owing to one or both of the causes noticed in Mr. Tredgold's remarks upon the
subject, which we have quoted under the word GAs, the liquefiable gases are not
so applicable as mechanical agents as the vapour of water or steam. Another
difficulty attending such application arises from the very imperfect means we
are at present acquainted with of producing the degree of cold necessary for
the purpose of condensing the gases; for the present, therefore, there seems
little hope of advantageously substituting these gases for steam as a prime
mover of machinery.
GAS WACUUM ENGINE. An engine working by the pressure of the
atmosphere, a partial vacuum being obtained by the combustion of hydrogen
gas in a close vessel. The first person who proposed obtaining power by this
means we believe to have been the late Mr. Cecil, of Cambridge, who published
some account of his plan, the details of which we do not rightly recollect. In
1824 Mr. S. Brown took out a patent for an engine upon this principle, and at
that time the invention excited considerable interest, and was by many looked
upon as likely to supersede the steam engine; but although the inventor has since
been perseveringly employed, and at a great expense, to bring the machine to
perfection, we apprehend he has met with no great success, as the only instances
in which we have heard of it being brought into actual use was on one occasion
GAS WACUUM ENGINE. 613
i. raising water on the Surrey. Canal, at Croydon, and at another time,
or a similar purpose, upon a canal in Oxfordshire; and very contradictory state-
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4 I
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raising water, which, by being led on to a water wheel, may also impart a rota-
tory motion to machinery; but this latter purpose may be effected by means
of pistons working in cylinders. The method of producing the vacuum is as
follows:—inflammable gas is introduced along a pipe into an open cylinder or
vessel, whilst a flame placed on the outside, but near to the cylinder, is kept
constantly burning, and at times comes in contact with the gas therein, and
ignites it; the cylinder is then closed air-tight, and the flame is prevented from
coming in contact with the gas in the cylinder. The gas continues to flow into
the cylinder for a period, and is then stopped off; during that time it acts
by its combustion on the air within the cylinder, and, at the same time, a part
of the rarefied air escapes through one or more valves, and thus a vacuum is
effected; the vessel, or cylinder, is kept cool by water. The two cylinders c
and d are the vessels in which the vacuum is to be effected; from these descend
the pipes gig and hjh, leading into the lower cylinders waſ, from which the
water rises along those pipes to fill the vacuum cylinders alternately. The water
thus supplied is discharged through the pipes B into the tank or trough Z,
whence it falls upon the overshot water wheel, and by the rotatory motion thus
produced, gives power to any machinery which may be connected with it. The
water runs from a wheel along a case surrounding the lower half into a reser-
voir v, from which the lower cylinders a w are alternately supplied. In order
to produce the vacuum, the gas is supplied to the cylinders by means of the
pipe k k k attached to a gasometer. The gas also passes along the small pipe
ll (communicating likewise with the gasometer), and being lighted at both ends
of that pipe is kept constantly burning for the purpose of igniting the gas
within the cylinders. The water in the reservoir v passing down one of the
pipes winto one of the lower cylinders w, causes the float y in that cylinder to
rise, and pushing up the rod o raises the end b of the beam, which of course
draws up with it the cap f and forces down the cap e of the other cylinder c.
The gas being admitted along the pipe k, the flame from the pipe h is now
freely communicated to the gas in the cylinder, through the orifice, by the
opening of the sliding valve s, which is raised by the arm r, lifted by the rod o
by means of the beam. To produce the intermitting action of each cylinder,
some intermediate machinery is put in operation by chains and rods attached to
a glass or iron vessel p, partly filled with mercury, and turning upon a pivot;
each end receives its movements of elevation and depression from the rise and
fall of the projecting arms q, by the action of the beam above, the mercury
being employed for the purpose of regulating the supply of gas into the cylin-
ders, and the movement of the slide in the trough v. By the action thus com-
municated the water from the reservoir flows down the pipe winto the vessel ar,
and produces the elevation of the float y and of the rod n, and raises the cap e
by the ascent of the beam at a. The motion thus caused in this part of the
machinery acting upon its duplicate parts on the other side, of course produces
by its action a corresponding movement, and the slider in the trough v, moved
by the action of the mercurial tube p being moved from its position, allows the
water to fall into the pipe w, and as it ascends, suffers the float y to descend,
and rising into the main cylinder, thus lifts again the beam at 5 and its con-
nexions, and forces down the cap e on the top of the other cylinder. After the
vacuum is effected in the cylinders, the air must be admitted to allow the water
to be discharged, and the caps to be raised; this is accomplished by means of a
sliding valve in the air-pipe m m, acted upon by chains t t attached to floats in the
reservoir, and as motion is given to them, the valve is made to slide backwards
and forwards, so as to allow of the free admission of atmospheric air- Chains
w u with suspended weights open the cocks in the pipe # k, and produce the
alternate flow of the gas, and regulate and modify its supply. In the pipes gig
and hj h, are docks to prevent the return of the water when the air is admitted
into the cylinders. -
GATE, in Architecture, a large door leading or giving entrance into an open
area, as a field or court-yard, or into a considerable building, as a palace or
prison. An excellent method of hanging gates of large dimensions, has been
introduced by Mr. H. R. Palmer, which is a useful application of his suspen-
GAUGES. G15
sion railway (see RAILWAY). The following cut represents some sliding or
rather rolling gates at each end of the northern avenue of the London Docks,
between the warehouses and the basin, forming not only a useful barrier to
prevent the intrusion of improper persons during the intervals of cessation of
public business, but producing also an ornamental effect. During the hours of
business these gates are rolled back against the side walls of the end ware-
houses, to which they stand close and parallel, occupying no useful room. In
opening or shutting them nothing need be moved out of the way, and it is done
with great facility and dispatch. Being suspended entirely from above, and not
even touching the surface of the ground, it is not subjected to the adventitious
obstacles common to other gates. . a a is intended to represent part of the wall
of the ranges of warehouses, and b the extremity of the range of sheds on
the opposite side of the avenue; c c a double railway, extended entirely across
the avenue from a to b, and likewise to the width of a gate beyond on each
side; it is supported by slightly curved arches of wrought iron, with ornamental
scroll-work between the arches and the double rail, the superstructure resting
upon lofty columns of cast-iron. One of three gates d (each of which fills up
e ^ &
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the space between two columns) is shown in the act of being closed, by a man
pushing it along; from its large dimensions and great weight (though chiefly
composed of wood) this could not be easily effected by the simple force of one
man, but being constructed on the principle of Mr. Palmer's patent railway, the
friction is reduced to very inconsiderable amount, the whole weight of each
gate being entirely suspended by iron rods to the axles of the little wheels
which run on the top of the railway, which are kept in their tracks by their
peripheries being flanged; the gates do not rest upon or even touch the
ground, but are merely guided in their course by means of a projecting edge
fixed in their path: this will be easily explained by means of the annexed
diagram, which represents a transverse section
of these parts. ff are two plates of iron, with
raised edges in the middle, which are screwed
down to open sleepers gg, and above these is
shown an edge view of the lower ends of the
gates, which run on either side of the column h.
Gates upon the same principle have been put up
at the court-yard at the Admiralty, and various
other public situations.
GAUGE. An adjustable standard of measure
employed in various arts where a number of articles of the same kind are re-
quired to be as nearly as possible of the same dimensions. Gauges are various,
constructed according to the purposes to which they are to be applied. The
cut on the following page represents a gauge contrived by Mr. H. R. Palmer,
for the purpose of making a line along the centre of any parallel or tapering



616 GAUGES.
solid. It answers all the purposes of a common carpenter's gauge, whilst it is
peculiarly serviceable in other respects, for which the common gauge is wholly
inapplicable; in making mortices, and enabling workmen to measure from a
centre line, and to work with greater accuracy and facility; and in many other
cases it will be found a very convenient instrument. a is a square bar of hard
wood, having two sliding cheeks b d
fitted tightly to it; the cheek b is
fixed fast on one end of the bar,
whilst the other slides upon it, but it
may be made fast at any required
place by means of the thumb screw
c; at the end b a common scribing
point is fixed in the bar, and with
this and the sliding piece d it forms
the common gauge used for drawing
parallel lines from the edge of any
piece of wood work. The addition -
made by Mr. Palmer consists of the two brass arms f and g, of equal lengths,
and which are centered in the two sliding cheeks at a a ; the other ends are
jointed together by the screw h, which is formed into a sharp conical point
beneath to mark the work with. In using this gauge it is evident that the point
of the screw h will always keep in the centre between the two cheeks b d. If
the work is not parallel in its width, then the screw c must be loosened, and
the two cheeks b d must be kept pressed towards each other, so as to be in
contact with the sides of the work, when the point g will traverse along the
centre of the piece as correctly as if the sides were parallel, because in all
situations it preserves an equal distance from the two cheeks b and d, these
cheeks have grooves made in them to receive the brass arms f and g when the
cheeks are brought into contact. ,
GAUGE, PREssure. An instrument to determine the pressure exerted in
hydrostatic or pneumatic machines, as the hydrostatic press, air pump, and
steam engine. When the pressure exerted is less than the pressure of the
atmosphere, as in the condenser of a steam engine, the gauge is usually termed
a barometer, and consists simply of a barometer tube, the lower end of which
plunges in a cup containing mercury open to the atmosphere, whilst the upper
end communicates with the condenser, and the degree of exhaustion or vacuum,
as it is usually termed, is measured by the altitude of the column of mercury in
the tube above the surface of the metal in the cup. When the pressure exerted
does not exceed two or three times the force of the atmosphere, it may be
measured by means of an inverted syphon or bent tube of wrought iron con-
taining a portion of mercury; one leg of the tube communicates with the vessel
in which the pressure is exerted, and the other leg is open to the atmosphere, and
contains a float by which the rise of the mercury is indicated; but when the
pressure is very great, a tube of sufficient length to support the corresponding
column of mercury would be extremely inconvenient, and it is usual then to
measure the pressure by the compression of a volume of air contained in a
glass tube, the upper end of which is sealed, whilst the communication of the
air in the tube with the chamber in which the pressure is exerted is intercepted
by a quantity of mercury in the lower part of the tube, and the pressure in the
chamber acting upon the surface of the mercury exposed to it causes the mer-
cury to rise in the tube, and to compress the air therein into a smaller space,
which space will be inversely, as the pressure exerted. The figure on page 617
represents a pressure gauge upon this principle, described in No. LXIII. of the
Philosophical Magazine, by Mr. H. Russell. The gauge consists of a glass tube,
sealed at one end, with a ball blown very near the other, leaving only as much
beyond the ball as may be necessary for connecting it with the pipe leading
from the vessel containing the condensed steam or gas, or other elastic vapour.
This ball, when the tube is filled with air, and subject only to atmospheric
pressure, should be about three quarters full of mercury, and the whole capa-
city need not exceed that of the tube more than as two to one. That the

GAUGES. 617,
divisions in the scale may be in geometrical progression, the tube is placed in a
horizontal position; this renders the instrument altogether so simple in appear-
ance, that persons totally unacquainted with instruments of this description,
may at once be brought to understand its mature, and be able to affirm with
confidence the degree of pressure to which it is subject. To determine
the degree of pressure at any point, ascertain the distance from the sealed end
of the tube, and by that measure divide the length contained between the
sealed end and the bulb, the quotient will be the number of atmospheres. Thus
in general terms, where T represents the whole tube, P the part into which the
column of air is compressed, and A the number of atmospheres, we have
†—A. Thus, suppose the tube 8 feet long, and the column of air compressed
into half that length, then w have #=2 atmospheres. If this column be again
** * * * tº , a 3 e
compressed into half its volume, it will be represented by 3–4 atmospheres;—if,
again, compressed into half its volume, we have ; =8 atmospheres;--if, again,
(8 feet=96 inches) # =16 atmospheres;—and lastly, *=32 atmospheres. In
the above figure the mercury chamber is blown in the tube itself, so that in this
plan we have no joints whatever to make in the instrument; and being placed
in a horizontal position at a convenient distance from the floor, all parts of the
scale may be examined with equal facility. For the internal diameter of the
tube, perhaps one-sixteenth of an inch will be found preferable.
GAUGE, RAIN. An instrument for showing the depth of rain or quantity
falling on a given surface at any place. These instruments are variously con-
structed; the one shown in the engraving on the following page is the inven-
tion of Mr. Crossley, and is an elegant application of his patent liquid metre.
The principal parts of this machine, which are enclosed in a small box a a and b,
are, a small tin vessel or tumbler e,f, which is divided into two equal parts by a
vertical partition, where it is supported by pivots on the upright stem I. The
pivots are placed below the centre of gravity of the tumbler, so that when it is
tilted (as represented in the engraving), it will remain in that position till the
upper half receives such a quantity of water as will overbalance it, when the
end c will be depressed by the weight of the water, and emptied; the end f
will, in consequence, be elevated and brought under the spout to receive the
water until it becomes sufficiently loaded to preponderate, when it will again
take the position in the figure. Attached to this tumbler is a forked projection,
that at every change of position, acts on a lever at h, and thus communi-
cates motion to a train of wheels, which, by the index and the dial face i, is
made to register the number of times the divisions of the tumbler have been
filled. The rain is received and conveyed into the tumbler by the hopper-
shaped vessel c c, the mouth of which must be made of an area, having such a
relation to the other parts that the index will point out the number of inches
of rain falling on that extent of surface; or, in other words, how deep the
water would have become had it remained on the surface of the earth during a
single shower, a day, a month, or even a year, if required, and this, too, without any
attention or care being bestowed upon it—for the apparatus is so simple in con-
struction, that it is not subject to derangement of its parts; and as it registers
during the falling of the shower, it requires no estimation to be made of the

618 GAUGINC.
T.
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quantity of water evaporated between the falling of the rain and the time of
observation.
GAUGING.—The art of measuring the capacities of all kinds of vessels.
Gauging of course forms a part of mensuration, and is accordingly treated
of by most writers on that branch of science; but as casks are seldom of any
exact mathematical forms, the rules laid down by such authors must be con-
sidered as merely theoretical; and in practice, gauging is performed mechani-
cally, by means of the gauging or diagonal rod, or by the gauging sliding rule.
" ne diagonal or gauging rod is a rod or rule adapted for determining the con-
tents of the casks, by measuring the diagonal only ; viz. the diagonal from the
bung to the extremity of the opposite stave next the head. It is a square rule,
having four sides or faces, and is usually four feet long, and folds together by
means of joints. Upon one face of the rule is a scale of inches, for taking
the measure of the diagonal ; to these are adapted the areas, in gallons, of
circles to the corresponding diameters. Upon the opposite face is a scale,
expressing the contents of casks, having a corresponding diagonal; and these
lines constitute the difference between the diagonal rods and the slide rules.
To use the diagonal rods, put the rod in at the bung hole of the cask, until its
end touch the opposite stave at the farthest possible distance from the bung-
hole, and note the inches and parts cut by the middle of the bung; then draw
out the rod, and look for the same inches and parts on the opposite face of it,
and on them will be found the contents, in gallons. The sliding rule is similar
to the common sliding Gunters, (see GUNTER’s ScALE,) but having certain divi-
sors, or gauge points at different points of the scale, pointed out by small brass
pins, which divisors are the number of cubic inches in any particular measure,
as malt bushels, or imperial gallons, the casks are gauged approximately as

GAUGING. 619
cylinders, taking a mean diameter, for which purpose they are generally
reduced to what is called four varieties; and if the difference between the head
and the bung diameters does not exceed six inches, their mean diameters may
be found by multiplying the difference of the first by '68; of the second, by
•62; of the third, by 55; and of the fourth, by 5; the respective products of .
these numbers, added to the head diameter, will make a mean diameter.
Having found a mean diameter, the contents are found by setting the length
of the cask upon the line marked B, on the brass slider, against the gauge-
point, for gallons, on the upper line A, upon the rule, and against the mean
diameter upon the lower line D; upon the rule will be found the contents on
C upon the slider. On the back of the rule are four other lines, differently
marked. The first line is marked D, and is similar to the same line upon the
opposite side, and upon this line are set the circular gauge-point for wine, and
various other gauge-points; the second line is upon the slider—it is marked C,
and is similar to the same line C upon the opposite face; the third and fourth
lines on this instrument are two lines of segments, for ullaging the casks, as it
is termed, that is, finding the contents of a cask, only partly full. One of these
lines is marked S S, for segment standing, and the other S L, for segment
lying; these lines are set upon the rule, and are both numbered alike, from 1
to 10, and from 10 to 100. To find the ullage of a lying cask by the line of
segments, having the bung diameter, the depth of the liquid in inches, and the
contents of the cask, set the bung diameter on C to 100, on the line of seg-
ments marked S L, and opposite the depth of liquid on C will be a number on
the line of segment, which call the reserved number; then set 100 on A to the
contents of the cask upon B, and against the reserve number before found upon
A is the contents of the cask upon B. To find the ullage of a cask standing,
substitute the length for the bung diameter, and the line SS, for the line S L,
and proceed as before.
To facilitate computations in gauging, Mr. W. Gutteridge has invented a
series of new units of measure, which has received the approbation of every
individual member of the Commission of Weights and Measures. These units
of measure are numbered 1, 2, 3, 4, 5, 6, 7, 8, No. 4 being the common
decimal foot, which is introduced to complete the series. These units are all
decimally subdivided into 100 equal parts, and are the roots of the cubic and
superficial measures in which the capacities of vessels, or solid contents of
bodies are reckoned, as gallons for liquids, and cubic feet for timber. By this
means, no division is necessary in computing contents or capacities, for the area
expressed in Mr. Gutteridge's system of notation multiplied by the depth gives
the contents; whereas, when the dimensions are taken in inches, after multi-
plying the area by the depth, it is necessary to divide the product by the num-
ber of inches in a gallon or a foot to find the contents. Mr. Gutteridge's units
of measure, with their data, are as follows:
For imperial Gallons.
No. 1. W 277,274. . . . . . = 6.52083 Inches. = 1 Units.
2. 4% 277.274 × 4/ '#. . = 7-35784 » = 1 »
3. V 277; . . . . . = 7-0676 , = 1 ,
4. is the common foot.
For Feet.
No. 5. A/ 'H. . . . . . . = 1.12836 Feet. = 1 Units,
6. V ºr . . . . . . = 1.08383 , = 1 .,
7. * - . . . . . . . = 1.2732 22 = 1 »
7854
8, 4% 144. . . . . . . = 5-2415 Inches. = 1 22 \
In connexion with the subject of gauging, we may notice a singular circum-
stance related by Mr. Gutteridge. He had been called in to gauge a new vat
for Messrs. Booth & Co. distillers, and his own system was employed as affording
620 GAUGING.
greater accuracy than the inch method in common use. After the dimen-
sions had been taken, a glass tube was fixed on the outside of the vat, for
reading off the quantities within, as a means of comparison with the interior
dip. That no difference might arise from the effect of capillary attraction,
the tube was made of more than an inch bore, and was fixed perpendicularly,
with a graduated scale placed closely, so that the zero of the scale coincided
with the top of the ungula, which exactly covered the bottom, without pro-
ducing any sensible depth of wet at the dipping place, from which it was
inferred that the interior dip, and the exterior indications of level would be
always the same; and upon putting in several determined quantities, those
quantities were indicated by the tube exactly; but a difference was afterwards
perceived between the interior dip and the exterior level, and the greater the
quantity, the greater the difference. The experiment was frequently repeated,
with every precaution to guard against error, one source of which was the
difference of temperature in the vat and in the tube, amounting in one
instance to 23 degrees, which would cause a difference of about 085 of an
inch, (the spirit being 41.6 per cent. over proof) but to save computations
of this sort, the time chosen for the principal experiment was when the tem-
perature was alike. With 1400 gallons in the vat, the difference was about ºff of
an inch; 2200 gallons more were then pumped in, and the difference increased
to # of an inch, and on adding 700 gallons more, the difference amounted to
1; inch. It appearing highly improbable that the timbers could compress so
much more under the dipping place than under where the tube was fixed, a
level of the two surfaces was taken, and, extraordinary as the fact may appear,
there was a difference found in the levels, of , of an inch, the liquid being
that much higher in the vat than the tube. This difference, Mr. Gutteridge
imputes to a difference in the specific gravity of the spirit within the vat, and
that within the tube, and upon assaying them the former was found to be nearly
5 per cent. stronger than the latter. This variation must have been caused
by a greater evaporation on the tube, and it shows that with spirits of such
great strength, evaporation is very rapid, and cannot be too carefully guarded
against. The remaining difference between the dip and the level in the tube
Mr. Gutteridge supposes to have arisen from a compression of the timbers under
the dipping place.
The following diagrams of the vat, tube, and timbers, will render the subject
more intelligible. Fig. 1 represents a section of the vat, a b being the tube
fixed into a metal pipe b c, with a cock at c d, the level of the spirit in the
vat; f the level in the tube, and h i the dipping place. Fig. 2, shows the sup-
- Fig. 2. 33
rºl. 2-Tºs.
złº-ºº::::::==T=14 #F Eº
ſºlº || |*| HR
h;
#
THIL
| | | | | | | |
WH T-I-H H
Ž
&
Ports of the vat ; B the back, and F the front, of which the seven similar parts
a a are the immediate rests, each four inches square; b b b the three timbers
upon which the former rest, 104 inches deep, and 12% broad; c c the two
sleepers upon which the beams are laid. The places d ddd are supported upon
fºur upright posts, and under k was placed another support; l the orifice for
the tube pipe, and o the dipping place.


GEARING. 621
GAUZE. A thin, transparent kind of stuff, woven sometimes of silk, and
sometimes of thread. To warp the silk for the making of gauze, a peculiar
kind of mill is used, upon which the silk is wound: it is a wooden machine,
about six feet high, having an axis perpendicularly placed in the middle thereof,
with six large wings, on which the silk is wound from off the bobbins by the
axis turning round. When all the silk is on the mill, another instrument is
used to wind it off upon two beams; this done, the silk is passed through as
many little beads as there are threads of silk; and thus rolled on to another beam
to supply the loom. The gauze loom is much like that of the common weaver's,
though it has several appendages peculiar to itself. Some gauzes are wrought
into figures and flowers of gold and silver, upon a silk ground.
GEARING. A train of toothed wheels, for transmitting motions in
machinery. There are two sorts of gearing in common; viz. spur gear and
beveled gear. In the former, the teeth are arranged round either the concave
or convex surface of a cylindrical wheel in the direction of radii from the
centre of the wheel, and are of equal depth throughout. In beveled gear,
the teeth are placed upon the exterior periphery of a conical wheel in a
direction converging to the apex of the cone, and the depth of the tooth
gradually diminishes from the base. For the rules for setting out these wheels,
and for the best form of teeth, we refer to the article MILL Work, and shall,
in this place, only notice a new system of gearing, invented simultaneously
by Mr. Dyer, in America, and by Messrs. MºDougall, of Ferry Bridge,
in Yorkshire, and communicated by the former gentleman to Mr. H. Burnett,
who took out a patent for the same. The object of this invention is to
obtain a great difference in the relative velocities of the wheel and pinion, by
a construction which in some respects resembles what is called a worm
wheel, or a wheel driven by an endless screw, but is at the same time free
from the objections attending the ordinary arrangement of the wheel and
endless screw. The common application of the wheel and endless screw is
in the direction of a tangent line, (or very nearly so) to the wheel to which
it is applied, and the force exerted upon it or by it, is constantly in a direc-
tion coincident with its longitudinal axis, and never in that of its radius,
whilst a rubbing action takes place between the threads of the screw and the
teeth of the wheel, thus producing excessive friction, not only at the point of
contact, but also against the pivot or resisting point of the screw. In the
patent gearing, the axis of the 'screw, or spiral pinion, is not a tangent to the
wheel, but lies in the same plane as the axis of the wheel in ordinary gear,
whether it be spur gear or beveled gear. The consequence of this arrange-
ment is, that the power of the screw or spiral is exerted in the direction of its
radius; consequently, it can be driven by the wheel with the same facility with
which the wheel drives it (difference of leverage, according to their respective
radii, excepted), which is not the case with the ordinary wheel and screw.
Another advantage is, that there being but one point of bearing in action at
once, and that uniformly on the line of centres, and that action passing uniformly
over equal spaces, in equal times, and in the same direction; the action which
takes place between the wheel and the spiral pinion is not a sliding, but a perfect
rolling action, whereby nearly the whole of the friction which would otherwise
occur, is avoided. One valuable property of this invention is, that any required
strength may be given to the arbor, without affecting its power or velocity; this
will be rendered evident by an inspection of Fig. 3 on the following page, in which
the external lines e e and ff represent the sections of two arbors of very different
sizes, and consequently strengths, while their mechanical action is precisely similar,
for it will be seen that, notwithstanding the difference of magnitude in the two
sections, they have but one common pitch-line, marked i i in both figures, so
that both can work in the same wheel, and their power and velocity must be
equal. Fig. 4 represents the arbor or pinion engaged with the tooth of a wheel.
Another most important advantage belonging to this system of gearing, is the
simplicity which may be thereby introduced into machinery, and the consequent
diminution of friction; for since each tooth of the wheel will be equivalent to
an entire revolution of the arbor, a great saving may be effected; thus, for
4 K - -
62% GEARING.
instance, if a common wheel has 100 teeth, and works into a pinion of ten
leaves, the same power or velocity may be obtained by the new mode of gear-
ing, by using a wheel of only ten teeth, working into one spiral groove upon
the arbor; as an example of which Fig. 1 is a side, and Fig. 2 a front elevation
Fig. 1.
*...*
sº
sº
Fig. 2.
=
of a regulator clock, which is capable of showing hours, minutes, and seconds,
and will go for a whole year with once winding up, by a weight of only a few
pounds. The curve of the spiral groove on the arbor may be found by covering
the face of the wheel with a strip of thin paper, and marking the bevel of one
tooth upon it, when the extension of that tooth may be cut off and wrapped
round the arbor, which will give the form of the spiral, which may be marked
and Gut; but this is only a proximate method, and as the action of the improved
gearing, like that of all other gearings, depends mainly upon the perfect work-
ing ºf the teeth and grooves, it is better to cut the groove on the arbor, in a
regular and proper machine for cutting spirals and screws.


GEOMETRY. 623
GELATIN. An animal substance soluble in hot water, capable of assuming
a well known elastic or tremulous consistence by cooling, when the water is not
too alundant, and liquefiable again by increasing its temperature. This last
property distinguishes it from albumen, which becomes consistent by heat. It
is precipitated in an insoluble form by tannin, and it is this action of tannin on
gelat'n which is the foundation of the art of tanning leather.
GEMS. This word is used to denote such stones as are considered by man-
kind as precious. These are, the diamond, the ruby, sapphire, topaz, chrysolite,
beryl, emerald, hyacinth, amethyst, garnet, tourmalin, opal; and to these may
be added, rock crystal, the finer flints of pebbles, cat's eye, hydrophanes, chal-
cedony, moon-stone, onyx, cornelian, sardonyx, agates, and Labrador stone,
for which, consult the several articles respectively.
GEOMETRY. One of the most important of the mathematical sciences;
as it relates to the form, extension, and magnitude of bodies, and is conse-
quently the foundation of Mensuration. The most generally useful portion of
this science has been selected for our pages, which we here annex under the
usual distinctive appellation of Practical Geometry.
DEFINITIons.—A point is that which hath position, but not magnitude.
A line hath length, but not breadth or thickness, and may therefore be con-
ceived to be generated by the motion of a point.
A right line is what is commonly called a straight line, or that tends every
where the same way.
A curve is a line which continually changes its direction between its extreme
oints.
p Parallel lines are such as are equally distant from each other, and which, if pro-
longed ever so far, would never meet: such are the lines A B and CD, Fig. 1.
An angle is the space or corner between two lines meeting in a point, as
A B C, B denoting the vertex, or angular point.
A right angle is represented when one line stands upon another, so as not to
lean more upon one side than upon the other, as in the angles A B C in Fig. 3;
all right angles are equal to each other, being all equal to 90° ; and the line
A B is said to be perpendicular to CD.
Fig. 3.
Fig. 2. A.
Fig. 1. J.
*: -
A- <!?
C B IC)


Beginners are very apt to confound the terms perpendicular, and plumb or
vertical line. A line is vertical when it is at right angles to the plane of the
horizon, or level surface of the earth, or to the surface of water, which is always
level. The sides of a house are vertical. But a line may be perpendicular to
another, whether it stand upright or incline to the ground, or even if it lie flat
upon it, provided only that it make the two angles formed by meeting with the
other line equal to each other; as, for instance, if the angles A B C and A BD
be equal, the line A B is perpendicular to CD, whatever may be its position in
other respects.
When one line BE, Fig. 3, stands upon another, CD, so as to incline, the
angle E B C, which is greater than a right-angle, is called an obtuse angle;
and that which is less than a right angle, is called an acute angle, as the
angle E B D.
Two angles which have one leg in common, as the angles A B C and A B E,
are called contiguous angles, or adjoining angles; those which are produced by
the crossing of two lines, as the angles E B D and C B F, formed by CD and
E F crossing each other, are called opposite or vertical angles.
624 GEOMETRY.
A figure is a bounded space, and is either a surface or a solid.
A superficies, or surface, has length and breadth only. The extremities of a
superficies are lines.
A surface may be bounded either by straight lines, curved lines, or both
these. Every surface, bounded by straight lines only, is called a polygon. Pſ
the sides be all equal, it is called a regular polygon. If they be unequal, it is
called an irregular polygon. Every polygon, whether equal or unequal, has
the same number of sides as angles, and they are denominated sometimes
according to the number of sides, and sometimes from the number of angles
they contain. Thus, a figure of three sides is called a triangle, and a figure of
four sides, a quadrangle. -
A pentagon is a polygon of five sides.
A hea agon has six sides.
A heptagon has seven sides.
An octagon has eight sides.
A nonagon, nine sides.
A decagon, ten sides.
An undecagon, eleven sides.
A duodecagon, twelve sides.
When they have a greater number of sides, it is usual to call them polygons
of 13 sides, 14 sides, and so on.
Triangles are of different kinds, according to the length of their sides. . .
A right-angled triangle is that which has one right angle, as A B C, Fig. 1.
An acute-angled triangle, is a triangle which has all its sides acute, as Figs.
A and B.
An obtuse-angled triangle, is a triangle having one obtuse angle, as Fig. C.
An equilateral triangle, is a triangle having all its sides equal, as Fig. A.




A.
Fig. 1.
Tº C
- 4—A -
An isoceles triangle, is a triangle having two equal sides, as Fºg. B. ...
A scalene triangle, is a triangle having no two of its sides equal, as Fig. Q. .
Quadrangles or quadrilateral figures are of various denominations, as their
sides are equal or unequal, or as all their angles are right angles or not.
- E- v / 7
Every four-sided figure, whose opposite sides are parallel, is called a parallelo.
gram. Provided that the sides opposite to each other be parallel, it is
immaterial whether the angles be right or not. Figs. DE F and G, are all
parallelograms. -
When the angles of a parallelogram are all right angles, it is called a
rectangular parallelogram, or a rectangle, as Figs. E and D.
A rectangle may have all its sides equal, or only the opposite sides equal.
When all its sides are equal, it is called a square, as Fig. D. -
When the opposite sides are parallel, and all the sides equal to each other, but
the angles not right angles, the parallelogram is called a rhombus, as Fig. G.
!—a



GEOMETRY. " 625
A parallelogram, having all its angles oblique, and only its opposite equal,
is called a rhomboid, as Fig F.
When a quadrilateral, or four-sided figure, has none of its sides parallel, it is
called a trapezium, as Fig. H, consequently, every quadrangle or quadrilateral,
which is not a parallelogram, is a trapezium.
A trapeziod has only one pair of its sides parallel, as Fig. I. . .
A circle is a plane figure, bounded by a curve line returning into itself, called
its circumference, b d e, Fig. O, every where equally distant from a point within
the circle, which is called the centre, c.
The radius of a circle is a straight line drawn from the centre to the circum-
ference, as c d, Fig. O. The radius is the opening of the compass when a circle
is described; and consequently, all the radii of a circle must be equal to each
other.
A diameter of a circle is a straight line drawn from one side of the circum-
ference to the other through the centre, as a b, Fig. P. Every diameter divides
the circle into two equal parts.
A segment of a circle is a part of a circle cut off by a straight line drawn
across it. This straight line f h, Fig. R, is called the chord. A segment may
be either equal to, greater, or less, than a semi-circle, which is a segment formed
by the diameter of the circle, and is equal to half the circle, as in Fig. P.
A tangent is a straight line, drawn so as just to touch a circle without cutting
it, as de, Fig. T. The point where it touches the circle, is called the point of
contact; and a tangent cannot touch a circle in more points than one.
A sector of a circle is a space comprehended between two radii and an arc,
as a c b, Fig. T.
The circumference of every circle, whether great or small, is supposed to be
divided into 360 equal parts, called degrees; and every degree into 60 parts,
called minutes; and every minute into 60 seconds. To measure the inclina-
tion of lines to each other, or angles, a circle is described round the angula,
point, as a centre, as a b, Fig. T, and according to the number of degrees
minutes, and seconds, cut off by the sides of the angle, so many degrees,
seconds, and minutes, it is said to contain. Degrees are marked by 9, minutes
by ', and seconds by "; thus an angle of 48 degrees, 15 minutes, and 7 seconds
is written in this manner, 480 15' 7".
PRoBLEM I.—To divide a given line A B into two equal parts.
From the end of the line A and B, Fig. 1, as centres, and with any opening
of the compasses greater than half A B, describe arches, cutting each other in
c and d. Draw the line c d, and the point E, where it cuts A B, will be the


626 GEOM ETRY.
Iniddle required. This is often effected by practical men assuming a distance
as half, and setting off from each end of the line, and then bisecting the
space between the distances set off by the eye.
PRoBLEM II.--To raise a perpendicular to a given line A B, from a point
given at C.
Case 1. When the given point is near the middle of the line, on each side of
the point C, Fig. 2. Take any two equal distances, C d and C e, from d and e,
with any radius or opening of the compasses greater than C d or C e, describe
two arcs cutting each other in f. Lastly, through the points f, C, draw the
line fg, and it will be the perpendicular required.
Case 2. When the point is at, or near the end of the line, take any point d,
Fig. 3, on the side of the line on which the perpendicular is to be drawn, and
with the radius or distance d c, describe the arc e c.f., cutting e B in e and c.
Through the centre d, and the point e, draw the line e d.f, cutting the arc
e cf. in f. Through the points f c, draw the line fe, and it will be the per-
pendicular required.
PROBLEM III.-From a given point f. to let fall a perpendicular upon a given
line A B.
Case 1. From the point f Fig. 2, with any radius, describe the arc de, cutting
A B in e and d. From the points e d, with the same or any other radius,
describe two arcs, cutting each other in g. Through the points f and g draw
the line fg, and f C will be the perpendicular required.
Case 2. If the point be nearly over the end of the line, from it as at f Fig. 3,
draw a line e f obliquely to the other end; bisect ef, in d, and with the
radius d e draw the arc fee, cutting the given line at c, to which the required
perpendicular from f is to be drawn.
Fig. 2. Fig. 3,
Fig. 1. *>k
ProBLEM IV.--To make an angle equal to another angle which tº given, as a B
From the point B, Fig. 4 with any radius, describe the are a b, cutting the leg
B a, Bºb, in the points a and b. Draw the line D b, and from the point D,
with the same radius as before, describe the arc bf, cutting D b in b. Take the
distance b a, and apply it to the arc bf, from b to f. Lastly, through the points
Df, draw the line D f, and the angle b Df will be equal to the angle b B a, as
was required.
ProBLEM W.—To divide a given angle, A B C, into two equal parls or angles.
From the point B, Fig. 5, with any radius, describe the arc A. C. From A
and C, with the same, or any other radius, describe arcs cutting each other in d.
Draw the line B d, and it will bisect the angle A B C as was required.
Problem VI.--To lay down an angle of any number of degrees.
There are various methods of doing this. One is by the use of an instrument
called a protractor, with a semicircle of brass, having its circumference divided

GEOMETRY. 627
into degrees; similar to Fig. 6. Let A B be a given line, and let it be required
to draw from the angular point A a line making, with A B, any number of
degrees, suppose 40. Lay the straight side of the protractor along the line A B,
and count 400 from the end B of the semicircle; at C, which is 400 from B,
mark; then, removing the protractor, draw the line A C, which makes, with
A B, the angle required. Or, it may be done by a divided line, usually drawn
upon scales, called a line of chords. Take 600 from the line of chords, in the
compasses, and setting one at the angular point B, PRob. IV., with that open-
ing as a radius, describe an arch, as a b : then take the number of degrees of
which you intend the angle to be, and set it from b to a, then is a Bb the angle
required.
Fig. 4. Fig. 5.
a. -
IB
p B
sº
A C
Z ID 3×
PtobleM VII.-Through a given point C, to draw a line parallel to a given
Mine A B
Case 1. Take any point d, in A B, Fig. 7, upon d and C, with the distance
C d, describe two arcs, e C, and df, cutting the line A B, in e and d. Make
df equal to e C; through C and f draw C f, and it will be the line required.
Case 2. When the parallel is to be at a given distance from A B. From
any two points c and d, in the line A B, with a radius equal to the given d’s-
tance, describe the arcs e and f: draw the line C B to touch those arcs without
cutting them, and it will be parallel to A B, as was required.
Fig. 7.
JB
__* C Cr
DT) P-e-si-7-st
V 62 A. *— d. B
43- 13
ProbleM VIII.— To divide a given line A B, into any proposed number of
equal parts.
From A, Fig. 8, one end of the line, draw A C, making any angle with A B;
and from B, the other end, draw B 9 parallel to A C, making the angle A B 9
equal to B A C. In each of these lines A C, B 9, beginning at A and B, set off
as many equal parts, of any length, as A B is to be divided into. Join the
points C 5; 4,6; 3, 7; and A B will be divided as required.
PRobleM IX. — To find the centre ºf a given circle.
Draw any chord A B, Fig. 9, and bisect it with the perpendicular CD. Bisect
CD with the diameter E F, and the intersection O will be the centre required.
Or the intersection of two lines drawn perpendicularly through two of its
chords, will be the centre of a circle.

628 GEOMETRY.
ProBLEM X.--To draw a tangent to a given circle that shall pass through a given
point, A.
From the centre O, Fig. 10, draw the radius O A. Through the point A,
draw D F perpendicular to O A, and it will be the tangent required.
Fig. 9. Fig. 10.
A.
PROBLEM XI.--To draw a tangent to a circle, or any segment of a circle A B C
through a given point B, without making use of the centre of the circle.
Take any two equal divisions upon the circle, Fig. 11, from the given point B
towards d and e, and draw the chord e B. Upon B, as a centre, with the dis-
tance B d, describe the arc f d g, cutting the chord e B in f. Make d g equal
to df; through g draw g B, and it will be the tangent required.
PRoBLEM XII.-Given three points, A, B, C, not in a straight line, to describe a
circle that shall pass through them.
Bisect the lines A B, BC, Fig. 12, by the perpendiculars a b, b a, meeting
at d. Upon d, with the distance d'A, d B, or d C, describe A B C, and it will
be the required circle. *
Fig. 12.
Fig. 11.
ProBLEM XIII.--To describe the segment of a circle to any length A B, and
height CD.
Bisect A B, Fig. 13, by the perpendicular D g, cutting A B in c. From c
make c D, on the perpendicular, equal to CD. Draw A D, and bisect it by
a perpendicular ef, cutting D g in g. Upon g the centre, describe A D B, and
it will be the required segment.
Fig. 13.
Yū




GEOMETRY. 629
PROBLEM XIV.- To describe the segment of a circle by means of two rules, to
any length A B, and perpendicular height CD, in the middle of A B, without
making use of the centre.
Place the rules to the height at C, Fig. 14; bring the edges close to A and
B; fix them together at C, and put another piece across them to keep them
fast. Put in pins at A and B, then move the rulers round these pins, holding a
pencil at the angular point C, which will describe the segment.
PROBLEM XV.-In any given triangle to inscribe a circle.
Bisect any two angles A and C, Fig. 15. with the lines A D and D C. From
D, the point of intersection, let fall the perpendicular D E; it will be the radius
of the circle required.
PROBLEM XVI.-In a given square, to describe a regular octagon.
Draw the diagonals A B and CD, Fig. 16, intersecting at e. Upon the points
A, B, C, D, as centres, with a radius e C, describe the arcs hel, ke n, meg, fei.
Join f n, m h, k i, lg, and it will be the required octagon.
PROBLEM XVII.-In a given circle, to describe any regular polygon.
Divide the circumference into as many parts as there are sides in the polygon
to be drawn, and join the points of division. Or divide 360° by the given
number of sides, and set off from the radius of the circle, an angle equal to the
quotient, and its chord will be one side of the polygon, Fig. 17.
Fig. 15. Fig. 16. Fig. 17.
A. t Z
A: \\
/.
G 7/8, 7t; T J's
PRoblem XVIII.—Upon a given straight line, A B, to form a polygon of any
number of sides.
Produce the side A B to P, Fig. 18, and on A P from the centre B describe
a semicircle A C P; divide the semicircumference A C P into as many equal
parts as the number of sides intended; through the second division, from P,
draw the line BC; bisect A B and P C by perpendiculars cutting each other
in S; from S with the radius A S, BS, or CS, describe a circle A B C D E,
then carry the side A B or B C round the remaining part of the arc, which will
be found to contain the remaining sides of the number required. Fig. 18 is
an example of a pentagon; we shall give in Fig. 19 an example of a hexagon,
as in this figure we need not proceed by the general method: we have only to
make a radius of the given side A B, and take the points A and B as centres;
form the arcs A G and B G, and strike a circle with the radius G A or G B,
which will contain the six sides,


630 GEOM ETRY.
PRobleM XIX.-Öpon a given line A B, to construct an equilateral triangle.
Upon the points A and B, Fig. 20, with a radius equal to A B, describe arches
cutting each other at C. Draw A C and B C, and A B C will be the triangle
required.
PROBLEM XX. —To make a triangle, whose sides shall be equal to three given
lines DE F, any two of them being greater than the third.
Draw A B, Fig. 21, equal to the line D. Upon A, with the radius F, describe
an arc C.D. Upon B, with the radius E, describe another arc intersecting the
former at C. Draw A C and C B, and A B C will be the triangle required.
Fig. 20. Fig. 21.
A. AX i;
PRoblem XXI-To make a figure equal and similar to a given irregular figure,
A B C D.
Divide the given figure as A B C D, Fig. 22, into two or more triangles, by
the diagonal D B. Make E F equal to A B; upon E F construct the triangle
E F H, whose sides shall be respectively equal to those of the triangle A BD,
by the last problem. Upon H. F, which is equal to DB, construct the triangle
H F G, whose sides are respectively equal to D B C, then EFG H will be the
figure required.
A figure having more than four sides must necessarily be divided into more
than two triangles.
PRoBLEM XXII.--To make a square equal to two given squares.
Make the sides D E and D F, Fig 23, of the two given squares A and B, on
opposite sides of the same straight lines, they will form the sides of a right-
angled triangle F D E; draw the hypothenuse FE; on it describe the square
E F G H, and it will be the square required.
Fig. 23.
Fig. 22.
X)
4.
PROBLEM XXIII-Two right lines A B, CD, being given, to find a third
proportional.
Make an angle H E I, Fig. 24, at pleasure; from E make E F equal to A B,
and EG equal to CD: join F G. Take E I equal to E F, and draw H I parallel
to F. G.; then E H will be the third proportional required; that is, E F: E G : :
E. H. : E I, or A B : C D : : C D : E I.



GEOMETRY. 631
ProaleM XXIV.-Three lines being given, to find a fourth proportional.
Draw G H and GI, Fig. 25, making any angle H G I; take G. H. equal to
A B, G. I equal to CD, and draw H. I. Make GK equal to E F; draw K L,
through K, parallel to H. I; then G L will be the fourth proportional required,
that is G. H. : G. I. : : G. K. : G L, or A B: C D : : E F : G. L.
PROBLEM XXV-To divide a given line A B, in the same proportion as another
CD, is divided.
Make any angle K.H.I, Fig. 26, and make H I equal to A B; then apply the
several divisions of CD, from H to K, and join K. I. Draw, parallel to IK,
the lines e,f, g, h, i, k, l, by which the line H I will be divided as was required.
Fig. 24, Fig. 25. Fig. 26.
C—D A- TR
A i. C — I) A --- B
T. R C1 r 4. -*. y * tº a *D
x AG J.
la
lº Jº R' Gº Tºt Jº H.
PitoBLEM XXVI.-Between two given lines A B and CD, to find a mean
proportional.
Draw the right line EG, Fig. 27, in which make E F equal to A B, and FG
equal to C D. Bisect E G in H, and with H E or H G, as radius, describe
the semicircle E I G. From F draw F I perpendicular to E. G., cutting the
circle in I; and I F will be the mean proportional required.
ProBLEM XXVII.--To describe an ellipsis.
If two pins be fixed at the points E and F, Fig. 28, a string being put about
them, and the ends tied together at C; the point C being moved round, keeping
the string stretched, will describe an ellipsis.
The points E and F, where the pins were fixed, are called the foci.
The line A B passing through the foci, is called the transverse aris.
The point G bisecting the transverse axis, is the centre of the ellipsis.
The line C D crossing this centre at right angles to the transverse axis, is
the conjugate aris,
The latus rectum is a right line passing through the focus at F, at right
angles to the transverse axis terminated by the curve: this is also called the
parameter.
A diameter is any line passing through the centre, and terminated by the
CUIrVe.
A conjugate diameter to another diameter, is a line drawn through the centre,
parallel to a tangent, at the extreme of the other diameter, and terminated by
the curve.
A double ordinate is a line drawn through any diameter parallel to a tangent,
at the extreme of that diameter terminated by the curve.
Fig. 27.
A
*R

C-D
9.
632 GEOMETRY.
PROBLEM XXVIII.-The transverse aris A B, and conjugate aris CD of any
ellipsis, being given, to find the two foci, and from thence to describe the ellipsis.
Take the semi-transverse, A E, or EB, Fig. 29, and from C as a centre,
describe an arc, cutting A B at F and G, which are the foci. Fix pins in these
points; a string being stretched about the points, F, C, G, the ellipsis is described
as above.
PROBLEM XXIX.-The same being given, to describe an ellipsis by a trammel.
The trammel, Fig. 30, is an instrument consisting of two rulers fixed at right
angles to each other, with a groove in each. A rod, with two movable nuts,
works in this groove, and, by means of a pencil fixed in the end of the rod,
describes the curve. The operation is as follows:–Let the distance of the first
pin at B, from the pencil at A, be equal to half the shortest axis, and the dis-
tance of the second pin at C, from A, to half the longest axis; the pins being
put in the grooves, move the pencil at A, which will describe the ellipsis.
Fig. 29. Fig. 30.
*s
ProBLEM XXX. — To describe an ellipsis similar to a given one A D B C, to any
given length I K, or to a given width M. L.
Let A B and CD, Fig. 31, be the two axes of the given ellipsis. Through
the points of contact A, D, B, C, complete the rectangle G E H F ; draw the
diagonals EF and GH: they will pass through the centre at R. Through I
and K draw P N and O Q parallel to CD, cutting the diagonals E F and GH,
at P, N, Q, O. Join PO and N Q, cutting C D at L and M ; then I K is the
transverse, and M L the conjugate axis of an ellipsis, that will be similar to
the given ellipsis A D B C, which may be described by some of the foregoing
methods.
PRoBLEM XXXI.--To describe a parabola.
If a thread equal in length to B C be fixed at C, Fig. 32, the end of a square
A B C, and the other end be fixed at F; and if the side A B of the square
be moved along the line A D, and if the point E be always kept close to the
edge B C of the square, keeping the string tight, the point or pin E will describe
a curve E G I H, called a parabola.
Fig. 32.
Fig. 31.
G- ID Tº
~N t
A I \ - B
P M O
yº C JHI


GEOMETRY. 633
The focus of the parabola is the fixed point F, about which the string revolves.
The directria is the line A, D, which the side of the square moves along.
The axis is the line L K, drawn through the focus F, perpendicular to the
directrix.
The verter is the point I, where the line L K cuts the curve.
The latus rectum or parameter, is the line G H passing through the focus F,
at right angles to the axis I K, and terminated by the curve.
The diameter is any line M N, drawn parallel to the axis I K.
A double ordinate is a right line R. S, drawn parallel to a tangent at M, the
extreme of the diameter M. N, terminated by the curve.
The abscissa is that part of a diameter contained between the curve and its
ordinate, as M. N.
PRoBLEM XXXII.--To describe a parabola, by finding points in the curve; the
aris A B, or any diameter being given, and a double ordinate CD.
Through A draw E F, Fig. 33, parallel to CD; through C and D draw D F
and C E parallel to A B, cutting E F at E. and F. Divide B C and BD, each
into any number of equal parts, as four ; likewise divide C E and D F into the
same number of equal parts. Through the points 1, 2, 3, &c. in CD, draw the
Mines 1 a, 2 b, 3 c, &c. parallel to A B; also through the points, 1, 2, 3, &c. in
C E and D F, draw the lines 1 A, 2A, 3 A, cutting the parallel lines at the
points a, b, c ; then the points a, b, c, are in the curve of the parabola.
PRoBLEM XXXIII.--To describe an hyperbola.
If B and C, Fig. 34, be two fixed points, and a ruler A B be made movable
about the point B, a string A D C being tied to the other end of the rule, and
to the point C; and if the point A be moved round the centre B, towards G,
the angle D of the string A DC, by keeping it always tight, and close to the
edge of the ruler A B, will describe a curve D H G, called an hyperbola.
Fig. 34.
Fig. 35.
Fig. 33.
E. A. F
an sº
º
I ſ |
É
à l ſ
2 2 AZA).
\\ 2
2 3.
a-3T3TTT2-35
5-4-3-i-fi Hà-3-&
If the end of the ruler at B were made movable about the point C, the string
being tied from the end of the rule A to B, and a curve being described after
the same manner, is called an opposite hyperbola.
The foci are the two points B and C, about which the ruler and string
revolve.
The transverse aris is the line I H terminated by the two curves passing
through the foci, if continued.
The centre is the point M, in the middle of the transverse axis I H.
The conjugate aris is the line NO, passing through the centre M, and termi-
nated by a circle from H, whose radius is M. C, at N and O.
A diameter is any line VW, drawn through the centre M, and terminated by
the opposite curves.

634 GILDING.
Conjugate diameter to another, is a line drawn through the centre, parallel to
a tangent with either of the curves, at the extremity of the other diameter
terminated by the curves. -
Abscissa is when any diameter is continued within the curve, terminated by
a double ordinate and the curve; then the part within is called the abscissa.
Double ordinate is a line drawn through any diameter parallel to its conjugate,
and terminated by the curve.
Parameter, or latus rectum, is a line drawn through the focus, perpendicular
to the transverse axis, and terminated by the curve.
PROBLEM XXXIV.--To describe an hyperbola by finding points in the curve,
having the diameter or aris A B, its abscissa B G, and double ordinate D.C.
Through G draw E F, Fig. 35, parallel to CD; from C and D draw CE
and D F, parallel to B G, cutting E F in E and F. Divide C B and BD, each
into any number of equal parts, as four; through the points of division, 1, 2, 3,
draw lines to A. Likewise divide EC and D F into the same number of
equal parts, viz. four; from the divisions on C E and D F, draw lines to G; a
curve being drawn through the intersections at G, a, b, &c. will be the hyper-
bola required.
GILDING. The art of applying to various substances an extremely thin
coating of gold. If the substances to be gilt be metallic, this is effected by
simple adhesion of the surfaces; but if not, the gold is attached by means of
some adhesive medium. The simplest of all the kinds of gilding on metal is
that by which ‘. or silver wire is gilt. The bar, before it is given to the
wire drawer, is plated with gold by having several layers of gold leaf burnished
down upon them whilst hot; and being then subjected to the stronger compres-
sion which takes place in wire drawing, the gold and the other metal become
so perfectly united as to form, in fact, one substance; but the most usual way
of covering the face of metals with gold is by means of an amalgam, or, as it
is technically termed, water gilding. If the metal to be gilt be silver, it is first
soaked in warm muriatic acid, that the surface may be rendered perfectly clean,
and then washed in clean water, changed two or three times to get rid of the
whole of the acid; being afterwards dried and made moderately warm, a little
gold amalgam, also warm, is to be carefully and evenly spread upon the silver,
to which it will immediately adhere. The plate is then placed upon a con-
venient support over a charcoal fire, and the mercury is driven off by heat,
when the plate will be found entirely covered with a thin coating of pale dull
gold. The small roughnesses are now to be removed with a scratching brush,
composed of extremely fine brass wire, which renders the surface perfectly
smooth and bright; after which the colour is heightened by warming the piece
and smearing it over with gilder's-wax, which is a composition of bees'-wax,
red ochre, verdigris, and alum. The wax being burnt off over a charcoal fire,
and the piece quenched in urine, the colour of the gilding will be found to be
much heightened, after which it may be burnished or not, as may be desired.
The affinity of copper and its alloys not being so great as that of silver for
mercury, the adhesion of the amalgam is promoted by the action of nitric acid
in the following manner:—the piece of copper, a button for instance, after
being cleaned and burnished, is dipped in a solution of nitrate of mercury,
which, owing to the superior affinity of the copper for the nitric acid, is quickly
decomposed, and the mercury becomes deposited in a metallic state over the
whole surface of the copper, to which it strongly adheres; the gold amalgam
is now applied, and the rest of the process goes on as already described, Gild-
ing is rarely applied to other metals than silver, copper, and the alloys of
the latter metal. There are two methods of gilding wood, viz., oil gilding and
burnished gilding. Oil gilding is thus performed:—the wood is first primed or
covered with two or three coatings of boiled linseed oil and white lead, to fill
*p the pores of the wood, and to render the surface smooth and even. When
the priming is quite dry, a thin coat of gold size must be laid on; this is pre-
pared by grinding together some strongly calcined red ochre with the thickest
drying oil that can be procured; and previous to using it, it must be mixed with
GLASS. 635
a little oil of turpentine, that it may work freely. When the gold size is suf-
ficiently dry, leaf gold, cut into strips, is taken up by the point of a fine brush
and applied to the parts to be gilded, and is then gently pressed down by a ball
of soft cotton; the gold instantly adheres to the sticky surface, and, after a few
minutes, the dexterous application of a camel's-hair brush sweeps away the
loose particles of gold leaf without disturbing the rest. In a day or two the
size will be perfectly dry, and the operation is then finished. This method is
simple and durable, but will not admit of burnishing, and therefore wants the
high lustre produced by the next process: it is chiefly used for out-door work.
Burnished gilding, or gilding in distemper, is thus performed –the surface to
be gilt must be first covered with a thick coating of strong parchment size;
this coating being dried, eight or ten more must be applied, consisting of the
same size, mixed with fine plaster of Paris or washed chalk; and when the whole
is perfectly dry, a moderately thick layer must be applied of size, mixed with bole
or yellow ochre. While this last is yet moist the gold leaf is to be put on in the
usual manner; it will immediately adhere on being pressed by the cotton ball,
and before the size is perfectiy dry, those parts which are intended to be most
brilliant are to be carefully burnished with an agate or dog's tooth. This kind of
gilding will not withstand rain or even damp, and is therefore only applied to
in-door work, as picture frames, &c.; it may be cleaned with a soft brush and
hot spirit of wine, or oil of turpentine.
GIMBALS, in Sea Affairs, the brass rings by which a sea compass is sus-
pended in its box, forming a universal joint upon the principle of Hooke's, so
as to counteract the effect of the ship's motion, and f , keep the card hori-
zontal.
GIN, in Mechanics, a machine for driving piles, fitted with a windlass and
winches at each end, at which eight or nine men heave the rope from the
barrel or windlass, passing over the wheel at the top.
GLAIR. The white of eggs used as a varnish for paintings; for this pur-
pose it is beaten to an unctuous consistence, and commonly mixed with a little
spirit of wine to make it work freely, and a little lump of sugar, to give it body
and prevent it from cracking; it is then evenly spread over the picture with a
fine brush.
GLASS. A well-known transparent and brittle factitious substance, of which
the basis is silica, brought into complete fusion by the addition of one of the
fixed alkalies. There are several different kinds of glass, adapted to different
uses. The best and most beautiful, are the flint and the plate glass; these,
when well made, are perfectly transparent and colourless, heavy and brilliant.
They are composed of fixed alkali, pure silicious sand, calcined flints, and
litharge, in different proportions. . The flint glass contains, likewise, a large
quantity of oxide of lead, which, by certain processes, is easily separated.
Crown glass is that used for windows, and is made without lead, chiefly of
fixed alkali fused with silicious sand, to which is added some black oxide of
manganese, which is apt to give the glass a tinge of purple.
Bottle glass is the coarsest and cheapest kind; into this little or no fixed alkali
enters the composition: in this country it is composed of sand, and the refuse
of the soap boiler, which consists of the lime employed to render his alkali
caustic, and of the earthy matters with which the alkali was contaminated. The
most fusible is flint glass, and the least fusible is bottle glass; flint glass melting
at the temperature of 100 Wedgwood, crown glass at 309, and bottle glass at
470. Although glass when eold is exceedingly brittle, when heated to redness
it becomes one of the most ductile bodies known, and may be drawn into
threads so very delicate as to become almost invisible to the human eye : it is
extremely elastic, and one of the most sonorous of bodies. In making glass,
the materials undergo a preparatory process called fritting, which consists in
mixing them in the proper proportions, and submitting them to a moderate
heat for six hours, by which they are reduced to a pasty consistence, and form
what is called frit, which is cut into squares, and stored up for use; and as
the quality of the glass depends upon the age of the frit, the principai manu-
facturers endeavour always to keep a considerable stock of frit on hand. This
636 GHASS,
frit is introduced into large pots made of prepared clay, and in these is exposed
to a heat sufficient to melt it completely. When the fusion has continued the
proper time, the furnace is allowed to cool a little; in this state the glass is
exceedingly ductile, and will assume any shape, according to the fancy of the
workman. The vessels thus formed must not be permitted to cool very
quickly; hence they are put into a furnace, that the heat may pass off very
gradually, and this is called “annealing.” Having said thus much to give a
general idea of the process, we shall now proceed to describe, somewhat in
detail, the manual operations in the manufacture of glass; observing that,
owing to the excise laws, the different branches of the manufacture, viz. crown,
flint, plate, and bottle glass, are not carried on at the same works, but require
to be in separate establishments; we shall, therefore, select for description the
manufacture of flint glass, by which the various utensils in glass are produced.
The other branches differ principally in the number and arrangement of the fur-
naces; but in all of them, with the exception of plate glass, the glass is brought
into the desired form principally by means of a blowing pipe: the operation is
exceedingly simple: the workman has a tube of iron, the end of which he dips
into a pot of melted glass, and thus gathers a small quantity of it on the end
of the tube; he then applies the other end of the tube to his mouth, and blows
air through it; this air enters into the body of the fluid glass, and expands it
out into a hollow globe similar to the soap bladders blown from a tobacco pipe,
and by varied management of these globes while in a soft state, and with the
aid of a few simple tools, they are reduced into the forms of the different ves-
sels in common domestic use. The first thing to be described is the furnace:
it consists of two large domes set one over the other; the lower one stands
over a long grating, which is on a levé! with the ground; on this grating the
fuel is laid, and beneath it is a large arch, by which the air is admitted, and by
which the ashes may be removed. In the sides of the lower dome as many
holes or mouths are made as there are workmen to make use of the furnace,
and before each mouth a pot of melted glass is placed; the pots are very large,
like crucibles, and will hold from three to four hundred-weight of liquid glass;
they are supported upon three small piers of brickwork, resting on the floor of
the furnace. The form reverberates the flame from the roof down upon the
pots, and they are placed at some distance within the furnace, that the flame
may get between the wall and the pots. The upper dome is built upon the
other, and its floor made flat by filling up round the roof of the lower dome
with brickwork; there is a small chimney opens from the top of the lower dome
into the middle of the floor of the upper one, which conveys the smoke away
from it, and a flue from the upper dome leads it completely from the furnace ;
the upper dome is used for annealing the glass, and is exactly similar to a large
oven; it has three mouths, and in different parts a small flight of steps leads
up to each. The implements employed in the formation of glass vessels are
few and simple; the following are the principal : a blowing-pipe, which is
simply a tube of wrought iron about three feet long, and covered with twine
towards the mouth-piece, pliers and calliper compasses, a pair of common
shears to cut the glass, a very coarse flat file, and several small iron rods;
there is also a bench or stool with two arms, another stool or table with a
smooth cast-iron plate upon it, and upon the ground behind this stool is another
plate of iron.
We shall now proceed to describe, somewhat more minutely, the manufac-
ture of flint glass. The melting pots are charged with frit, thrown in by
shovelsful from time to time, allowing each portion to melt before a fresh
quantity is added. When the whole is converted into a clear transparent glass,
and is become perfectly pure and free from particles of sand or bubbles of air,
the gatherers and blowers commence operations, and continue working night
and day until the batch is exhausted. The process of blowing is varied accord-
ing to the form of the piece to be manufactured ; to illustrate it, it will be suf-
ficient to describe the method in which a wine glass is formed. When the
blower has received from the gatherer the blowing pipe charged with a sufficient
quantity of metal, he seats himself in a chair provided with two arms or elbows,
GLASS. 637
one of which is plated with iron, and placing the blow pipe across the elbows,
so that the heated end may rest on the iron plate, having first formed the glass
into a hollow ball, he rolls the pipe backwards and forwards, and laying hold
of the glass on the farther side of the ball with a small pair of pliers, draws
it out to form the stalk of the glass, while the part next the blow pipe is
fashioned into the bowl. In the mean time another blower, having formed a
smaller ball, opens it by a sharp cut, and presses it while red hot against the
end of the stalk held by the former workman, to which it immediately adheres;
the workman then with a piece of iron, which he wets with his mouth, touches
the globe intended for the bowl of the glass, which is still very hot, although so
much chilled as to retain its shape; in a second or two it cracks all round, and
by giving it a gentle knock it is detached from the blowing pipe. The workman
then instantly heats it, and with a pair of shears cuts the mouth smooth
and even; but as the shears have put the glass out of the circular form, he heats
it again, and by a dexterous twirl and swing round his head gives it the
desired shape almost without the use of any tools. The wine glass now finished,
the iron at the foot is detached by a smart blow, and the glass is carried by a
boy, upon a long forked iron, to the annealing oven. After the glass is annealed
it may be required to be cut before it is ready for sale: this, when the articles
are small, and can be easily held in the hand, is performed upon small grit
grindstones, or by circular plates of iron, revolving in troughs of sand and
water; and for beaded mouldings, as upon decanters, a corresponding groove is
formed upon the periphery of the plate. The operations are concluded by
polishing the cut parts by means of revolving straps covered with polishing
owder.
p In the manufacture of bottle glass, after the metal is brought into fusion,
which requires an intense heat during eighteen hours, it is reduced to the work-
ing temperature, which is steadily maintained by a due supply of fuel, and
being scummed, is ready for blowing. For carboys and similar articles it is
merely blown into a globular form; but for common wine bottles, or for square
or octagonal bottles or jars, it is blown within moulds. Each piece, as it is
blown, is handed over to the finisher, who forms the ring at the mouth of the
neck, and delivers it to a boy, to be placed in the annealing oven.
In making crown glass, as soon as the metal is ready for blowing, a workman
gathers on the blowing pipe a quantity of metal sufficient for forming a sheet
or table of glass, which he blows, and, by frequent rolling on a polished table.
brings it into a globular or cylindrical form; he then inflates it gently into an
oblong ball called a parisienne, and immediately heats it again at the mouth of
the furnace, in order farther to expand it; in this stage a solid iron rod, charged
with melted glass, is made to adhere to the centre of the expanded part oppo-
site the extremity of the blow pipe, and this latter is detached from the glass by
a cold iron, leaving an orifice, which is gradually enlarged by heating the glass
at the small hole of the flashing furnace, and afterwards at the larger hole of
the same furnace, the workman all the while wheeling the rod which supports the
glass on a hook in a cross wall, built to defend him from the heat. By degrees,
in consequence of the heat and the centrifugal motion, the opening of the glass
is continually enlarged, until it expands suddenly with great violence into the
form of a large circular plate, four or five feet in diameter, and of uniform
thickness, except at the centre, where it is attached to the supporting iron ; from
this iron it is separated by the application of cold, leaving in the centre a thick
nodule called the bull's eye; and when the plate is sufficiently firm to prevent
warping, it is carried to the annealing oven and placed on its edge in a proper
frame, to keep it flat till all the tables are ready for removal into the crates in
which they are kept.
Plate glass is formed either by blowing or casting: by the former method is
made the glass for carriage windows; and by the latter, the large plates for
looking glasses. Of late it is said that the art of blowing plate glass has been
so much improved, that plates measuring 60 inches in lengthſ by 21 in breadth
have been produced by this method; but by casting, much larger plates are
produced, and the establishment at Ravenhead has exhibited at their warehouse
4 M
638 GLASS.
near Blackfriars' Bridge plates of the extraordinary dimensions of 12 feet by 6.
The most perfect furnace for manufacturing plate glass appears to be that
which is employed in France. It consists of a central melting furnace of an
oblong form, with a double arched roof; it is capable of containing, upon a
raised bench on each side of the fire grate, two large melting pots and a cis-
tern ; in each angle of the furnace, and on each side, are two or three openings
for introducing the materials, transferring the melted metal from the pots to the
cistern, and withdrawing the latter when filled with metal: at each angle of
the principal furnace is another of an oblong form communicating with the
central one by flues, through which the flame reflecting from the arches of the
melting furnace reverberates on their contents. Each of these smaller fur-
naces has two openings, a smaller one for producing a current of air, and a
larger one for introducing and removing what is placed within them. Three of
them are usually employed for burning the melting pots and cisterns, which
are made of fire-clay; and the fourth is used for preparing the frit. Around
the plate glass house are several annealing furnaces like baker's ovens, with
capacious mouths. For receiving the melted metal from the pots, square cis-
terns of sufficient capacity to contain melted metal enough for one plate are
used, and when these are filled they are withdrawn from the furnace by means
of large iron tongs, supported upon an axle running upon two wheels; another
pair of tongs made to encompass the cistern by entering a groove on its sides,
and furnished at each end with a handle for the more convenient management
of it, is attached by four chains to a sort of crane for suspending and raising the
cistern into a proper position with regard to the table. The casting table con-
sists of an oblong frame of wood, covered on its upper surface with a thick
sheet of smooth copper, having at its sides two iron rulers of the thickness of
the intended plate, their distance asunder being regulated by the proposed
breadth of the plate. An iron roller of considerable weight, furnished with a
handle at each end, resting on the iron rulers at one end of the table, is made to
pass over the melted metal when poured upon the table, in order to form it into
a plate of uniform thickness. The apparatus just described is used only for
casting plate glass, that for blowing being so simple as to need no particular
description. In preparing the materials for plate glass they are first reduced
to powder, well mixed together and calcined in the fritting furnace before
described; they are then removed as quickly as possible into the melting pots
previously heated, and after being melted, which generally requires about ten
hours, the heat is continued at its utmost degree till the metal becomes perfectly
fine; it is then ladled from the pots into the cisterns, which are then drawn out
on projecting ledges, and conveyed to the casting table, over which they are
suspended by the crane, and by means of the handles of the tongs they are
inclined so as to allow their contents to flow over the table: the iron roller is
then immediately passed steadily over the surface of the melted metal, sweeping
off the superfluous matter into troughs placed at the sides of the table; and
when the roller reaches the further extremity of the table, it is expeditiously
lowered on a tressel, which prevents its interfering with the plate. The opera-
tion of casting is performed before the mouth of the annealing oven, in which
it remains exposed to a moderate heat for fourteen days, the heat being at last
suffered to die away as gradually as possible. When quite cool it is withdrawn,
carried to the magazine, examined, and cut square by a glazier's diamond, and
is then ready for the operations of grinding and polishing. The casting table
and tressel, as also the crane, are all mounted upon wheels, for the convenience
of removing them from one annealing furnace to another. When plate glass is
made by blowing instead of casting, after the materials have been fused as
before described, and become fine, the further admission of air is prevented by
closing all the openings of the furnace, and every thing is suffered to remain
stationary for nine or ten hours. This gradual cooling has been found necessary,
to enable the melted glass to adhere sufficiently to the blowing pipe. The mode
of blowing plate glass greatly resembles that used in the manufacture of
table glass, except in the quantity of metal gathered on the blowing pipe,
which is sometimes nearly 100lbs. When plates of the largest size are to be
GLASS, SOLUBLE. 639
formed, the metal is gradually blown and worked into the form of a cylinder,
which is cut open at one side with a pair of shears, and the soft glass is spread
on a heated floor, covered with a thick stratum of sand, and from thence is
speedily conveyed to the annealing furnace. In grinding plate glass, two plates
are always ground together, one being imbedded in plaster of Paris upon a
table, whilst the other, also imbedded in plaster, is placed upon the former, and
being loaded with great weights, is moved uniformly but pretty quickly over its
surface. Sand moistened plentifully with water is from time to time sprinkled
between the plates, and grinds away all the prominences of the glass until both
plates become smooth and even. As the grinding proceeds, sand of greater fine-
ness is employed; and towards the conclusion, it is exchanged for emery, also of
varying fineness. As by grinding the surface is roughened and rendered in-
capable of transmitting the rays of light, it becomes necessary to restore its
lustre by polishing, which is performed by rubbing the surface with a block of
wood, covered on the lower side with a woollen cloth. The workman keeps it
supplied with fine polishing powders, as tripoli and putty, changing from coarse
to fine, as the polishing advances to a conclusion. To regulate the pressure a
springing pole is put on the back of the block, which, being bent to a curve, is
supported from the ceiling of the workshop.
GLASS, (SoLUBLE.) A simple silicate of potassa or soda, which unites perfect
solubility in boiling water to some of the general properties of common glass.
In the liquid state, it may be applied to cloth or wood, for the purpose of ren-
dering them incombustible. In fact, by the evaporation of the water in which
it is dissolved, a layer of a substance capable of fusing when heated, is depo-
sited on these bodies, that protects them from the contact of air necessary for
their combustion. The following account of its manufacture and uses is
derived from a translation by Professor Renwick, of the Traité de Chimie
appliqué aux Arts, par M. Dumas.
Preparation.—Soluble glass may be obtained by dissolving pure silica, obtained
by precipitation, in a boiling solution of caustic potassa; but this process, being
both inconvenient and costly, cannot be practised upon a large scale. When
sand and carbonate of potassa are heated together, the carbonic acid is never
wholly driven off, except when the sand is in excess; but the whole of the car-
bonic acid may be expelled by adding powdered charcoal to the mixture, in
such proportion that the carbonic acid of that part of the carbonate which is
not decomposed may meet with a sufficient quantity of carbon to convert it
into carbonic oxide. In this way the silica first forms a silicate in the propor-
tions contained in common glass, and drives off the appropriate equivalent of
carbonic acid; then, at a high heat, the rest of the carbonate of potassa is
decomposed by the carbon, the carbonic oxide escapes, and the potassa thus
freed, either sublimes, or combines with the glass already formed.
The sand (freed from lime and alumina) and carbonate of potassa (pearl ash)
are taken in the proportion of 2 of the latter to 3 of the former, and to 10
parts of pearlash and 15 of sand, 4 parts of charcoal are added. A less
portion of charcoal must not be taken; on the contrary, if the form of
potash employed be not sufficiently pure, a larger proportion of charcoal
may be advantageously employed. This substance accelerates the fusion
of the glass, and separates from it all the carbonic acid, of which there
would otherwise remain a small quantity that would have an injurious
effect. In other respects, the same precautions that are employed in the
manufacture of common glass are to be observed. The materials must
be first well mixed, then fritted, and finally melted in a glass pot, until the
mass becomes liquid and homogeneous. The melted matter is taken out of
the pot with an iron ladle, and the pot is then filled with fresh frit. Thirty
pounds of pearlash, 45 of sand, and 12lbs., of powdered charcoal may be
taken for a charge; with this quantity the heat must be continued for five
or six hours. The crude glass thus obtained, is usually full of air bubbles;
it is as hard as common glass, of a blackish gray colour, and transparent at the
edges; sometimes it has a colour approaching to whiteness, and at others is
yellowish or reddish : these are indications that the quantity of charcoal has
64() GLASS, SOLUBLE.
not been sufficient. If it be exposed for some weeks to the air, it undergoes
slight changes, which rather tend to improve than injure its qualities. It
attracts a little moisture from the air, which slowly penetrates its mass, without
changing its aggregation or its appearance; it merely cracks; and a slight
efflorescence appears at its surface. If it be exposed to heat, after it have
undergone this change, it swells up, owing to the escape of the aqueous matter
it has absorbed. In order to prepare it for solution in boiling water, it must
be reduced to powder by stampers; if this were not done, it would dissolve too
slowly. One part of glass requires from 4 to 5 of water for its solution.
The water is first heated to ebullition in an open boiler, the powdered glass is
then added by degrees, and must be continually stirred, to prevent it from *
adhering to the bottom. The ebullition must be continued three or four hours,
until no more glass is dissolved: the liquor will then have acquired the proper
degree of concentration. If the ebullition be checked befores this state is
attained, carbonic acid will be absorbed by the potassa from the air, which will
produce an injurious effect; for the same reason, too great a quantity of water
must not be employed, for during the long evaporation which will then become
necessary, the carbonic acid of the water will readily combine with the potassa,
and cause a precipitation of the silica. When the liquor becomes too thick,
before the whole of the glass is dissolved, boiling water must be added. When
the solution has acquired the consistence of syrup, and a density of 1.24 to
1.25, it is sufficiently concentrated, and fit for use. It is then permitted to rest,
in order that the insoluble parts may be deposited; while it is cooling, a pellicle
forms upon the surface, which after a time disappears of itself, or may be redis-
solved by depressing it in the liquor. This pellicle begins to appear during the
ebullition, and indicates its concentration. When the crude glass is of a proper
composition it contains but a few saline impurities, and no sulphuret of potas-
sium, it may be treated in the way we have described; but if it contain any
notable proportion of these substances, they must be separated before it is dis-
solved; this separation may be effected in the following manner: — The pow-
dered glass is exposed to the action of the air for three or four weeks, during
which time it must be frequently stirred; and if it run into lumps, which will
happen in moist weather, they must be broken up. The glass, as we have
stated, attracts moisture from the air, and the foreign substances either separate
or effloresce. It then becomes easy to remove them from the glass. It is
sprinkled with water, and frequently stirred. At the end of three hours the
liquor is removed, it will then contain a part of all the saline impurities, and a
little of the silicate of potassa; the powder is again to be washed with fresh
water. Soluble glass thus treated readily dissolves in boiling water, and the
solution leaves nothing to be desired. To preserve it in the liquid form no
particular care is necessary, as even after a long space of time it undergoes no
perceptible change, if the solution have been properly prepared. The only pre-
caution is not to allow air too free an access to it. A similar product may be
obtained by using a carbonate of soda instead of one of potassa. In this case,
two parts of the soda of the shops is required for one of silica. This glass has
the same properties as the other, but is more valuable in its uses. The solu-
tions of these two kinds of glass may be mixed in any proportion whatever,
and this mixture is more serviceable in some cases, than either of them
separately.
Properties.—Soluble glass forms a viscid solution, which when concentrated
becomes turpid and opalescent: it has an alkaline taste and reaction. The
solution mixes in all proportions with water. When the density of the solu-
tion is 1.25, it contains nearly 28 per cent of glass; if the concentration be
carried beyond this point, it becomes so viscid that it may be drawn out in
threads like molten glass. Finally, the liquor passes to the state of a vitreous
mass, whose fracture is conchoidal; it then resembles common glass, except in
hardness. When the solution is applied to other bodies, it dries rapidly at
common temperatures, and forms a coat like a varnish. Soluble glass when
dried does not undergo any perceptible change when exposed to the air, nor
does it attract from it either moisture or carbonic acid; neither has the carbonic
GLASS, SOLUBLE. 641
acid of the atmosphere any well marked action on the concentrated solution;
but when a current of carbonic acid is passed through the solution, the glass is
decomposed, and hydrate of silica deposited. But a weak solution becomes
turbid on exposure to the air, and is after a time decomposed wholly. When
the glass is impure, an efflorescence is formed after a while, which may be pro-
duced either by the carbonate and hyposulphate of potassa, or by chloride of
potassium. Soluble glass dissolves gradually without residuum in boiling water;
but in cold water the solution is so slow as to have led to a belief that it does
not dissolve at all. It however never becomes entirely insoluble, except when it
contains a much larger proportion of silica, or when it is mixed with other bodies,
such as the earths, metallic oxides, &c., with which double or triple salts are
formed, as is the case in the common glasses. Soluble glass which has been
exposed to the air, and is afterwards submitted to the action of heat, swells and
cracks at first, and melts with difficulty; it then loses about 12 per cent. of
its weight. It therefore contains, even when solid, a considerable quantity of
water, which it does not lose when simply dried by exposure to the air. Alcohol
precipitates it unaltered from its solution in water. When the solution is con-
centrated, but little alcohol is required for precipitation, and it need not be
highly rectified. Pure soluble glass may therefore be easily obtained from an
impure solution by the use of alcohol. The alcohol being added, the gelatinous
precipitate is permitted to settle ; the supernatant liquor is decanted, the
precipitate collected, rapidly stirred after the addition of a little cold water,
and subjected to pressure. In truth, however, this process is attended with
some loss, for even cold water will rapidly dissolve the precipatated glass in
consequence of its minute division. The acids decompose the solution of
glass. They also act upon it when solid, separating the silica in the form of
owder.
P Uses.—The properties of soluble glass fit it for numerous and varied applica-
tions. It has been used in the theatre of Munich as a means of safety from
fire. All sorts of vegetable matter, wood, cotton, hemp, linen, paper, &c. are,
as is well known, combustible; but in order that they shall burn, two conditions
are requisite, an elevated temperature, and free contact of air, to furnish the
oxygen necessary for their transformation into water and carbonic acid. When
once set on fire, their own combustion develops the heat necessary to keep up
the chemical action, provided they be in contact with air. If deprived of such
contact, and made red hot, they will, it is true, yield inflammable volatile pro-
ducts, but the carbon which is left will not burn, as it is deprived of air, and
thus the combustion will stop of itself. Such is the part which all the fixed
fusible salts are capable of performing, if they be, in addition, composed of
substances incapable of yielding their oxygen at a low red heat, to either carbon
or hydrogen. These salts melt as the vegetable matter becomes heated; they
form upon it a coat impenetrable to the air, and either prevent altogether, or
limit its combustion. The phosphate and borate of ammonia have such a cha-
racter, but they are so readily soluble in cold water, as to be liable to objections
which cannot be urged against soluble glass. Although soluble glassis of itself
a good preservative from fire, it fulfils the object better when it is mixed with
another incombustible body in powder. In this case the solution of glass acts
in the same manner as the oil of painters. The several coats have more body,
become more solid, and more durable; and if the substance which is added be
af proper quality, coagulate by the action of fire into a strongly adhesive crust.
Clay, whiting, calcined bones, powdered glass, &c. may all be employed for
this purpose; but we cannot yet say with certainty which of them is to be
preferred. A mixture of clay and whiting appears to be better than either
used separately. Calcined bones form with soluble glass a very solid and
adhesive mass. Litharge, which, with the glass, makes an easily fusible mix-
ture, does not give a product fitted for coating wood, as the mixture contracts
in drying; it therefore cracks, and is easily separated. Flint glass and crude
soluble glass are excellent additions. The latter ought to be exposed to the
air after it is pulverized, in order to attract moisture. If it be mixed with the
solution, and be then applied to any body whatever it in a short time ferms a
642 GLASS, SOLUBLE.
coating as hard as stone, which, if the glass be of good quality, is unalterable
by exposure, and resists fire admirably. The scoriae of iron and lead, felspar,
fluor, may all be employed with soluble glass; but experience alone can decide
which of these substances is best, and in what proportion they are to be
employed. We should advise that the first coat should always be a simple
solution of the glass; and that a similar solution be applied over coats
composed of its mixture with other substances, particularly when such a
coat is uneven and rough. The last named substances form a solid and
durable coating, which suffers no change by exposure to the air, does not
involve any great expense, and is readily applied; but, in order that it
may not fail, particular care is to be taken both in preparing and employ-
ing it. In order to cover wood and other bodies with it, the solution must
be made of a pure glass, for otherwise it would effloresce and finally fall
off. However, a small degree of impurity is not injurious, although after
a few days a slight efflorescence will appear; this may be washed off by water,
and will not show itself a second time. When a durable covering is to be
applied to wood, too strong a solution must not be employed at first; for in
this case it will not be absorbed, will not displace the air from the pores,
and in consequence will not adhere strongly. It is a good plan to rub the
brush several times over the same place, and not to spread the coating too
lightly. For the last coats a more concentrated solution may be employed;
still it must not be too thick, and must be spread as evenly as possible. Each coat
must be thoroughly dry before another is applied; and this will take, in warm
and dry weather, at least twenty-four hours. After two hours the coat appears
to be dry, but is still in a state to be softened by laying on another. The same
inconvenience will then arise, which occurs when a thick coat of a concentrated
solution is applied; the coat will crack, and does not adhere. This, however,
is only the case when potassa is the base of the glass, for that formed from
soda does not appear to crack. In applying soluble glass to the woodwork of
the theatre at Munich, 10 per cent. of yellow clay (ochre?) was added. After
six months, the coat had suffered but little change; it was damaged only in a
few places where it had need of some repair. This arose from a short time only
having been allowed for the preparation and application of the glass, and they
were therefore done without proper attention. When this mode is employed
for preserving a theatre from fire, it is not enough to cover the woodwork, it is
also necessary to preserve the scenery, which is still more exposed to danger.
None of the methods yet proposed for this purpose appears as advantageous as
soluble glass, for it does not act upon vegetable matter, and completely fills up
the spaces between the thread; it fixes itself in the web in such a way that it
cannot be separated, and increases the durability of the fabric. The firmness
which it gives to stuffs does not injure them for use as curtains, because it
does not prevent them from being easily rolled. So far as the painting of
scenes is concerned, the glass forms a good ground for the colours. To pre-
vent the changes which some colours, Prussian blue and lake for instance,
might undergo from the alkaline matter, it will be necessary, before painting,
to apply a coat of alum, and then one of whiting. There is no great difficulty
in applying soluble glass to cloths; still this operation is not so easy as might
at first be imagined. It is not sufficient to coat or dip them in the solution;
they still require after this operation to be subjected to pressure. This object
might perhaps be best attained by passing them between rollers plunged in the
solution. When a cloth is only coated with soluble glass, and put into the fire, it
will remain incandescent after it is taken out. This is not the case when it has
been properly impregnated with this solution. A still better purpose is answered
in this case, when litharge has been added to the solution. The stuff in
drying yields to the shrinking of the mixture, and becomes inseparable from it,
which is the reverse of what happens when it is applied to wood. A single
part of litharge in fine powder is sufficient for fourteen parts of concentrated
liquor. Soluble glass is capable of many other applications, and particularly as
a cement; for this use it is superior to all those which have hitherto been
employed for uniting broken glass, porcelain, &c. It may be used in place of
GH, AZING, 643
glue or isinglass in applying colours, although when employed by itself it does
not make a varnish which will preserve its transparency when in contact
with air.
GLAUBER SALT. The sulphate of soda.
GLAZING, as it is now practised, embraces the cutting of all the varieties of
glass manufactured for windows, together with fixing it in sashes by means of
brads and a stopping of putty; also the forming of casements, and securing the
glass by bands of lead fastened to outside frames of iron. The most ancient
species of glazing was in head-work, as our numerous cathedrals and religious
houses still extant demonstrate; and fixing glass in leaden frames is still con-
tinued for the same description of buildings. The business of a glazier, if
considered in its most simple operations, consists in fitting al’ une various kinds
of glass manufactured and sold into sashes previously prepared to receive
them. The sashes, as they are now made, have a groove or rebate formed on
the back of their cross, and vertical bars adapted to receive the glass; into
these rebates the glazier exactly fits the squares, which he beds in a compo-
sition called putty. The putty consists of pounded whiting beaten up with
linseed oil, and so kneaded and worked together as to make a tough and tena-
cious cement, and is of great durability; this the glazier colours to suit the
sashes he may have in hand; if they are common deal sashes, the putty is left
and used as first manufactured; but if they are mahogany, it is coloured with
ochre till it approaches more nearly that of the sashes. In glazing windows the
colour of the glass is that on which the greatest beauty is given to the work;
and to effect this successfully, many different manufactories have been esta-
blished. The most usual kind of window glass now employed by the glaziers is
called crown glass; it is picked and divided at the manufactory into the several
different kinds, which are known as first, seconds, and thirds, and which par-
ticularly denote the qualities of the several kinds of glass, the first being known
as best crown, the next in quality second crown, and the last, thirds, or third
crown, the price of each varying according to the quality. The glass is in
pieces called tables, of about three feet in diameter each, and, when selected
and picked as above, they are packed in crates, twelve of such tables being put
in each crate of best glass, fifteen in the seconds, and eighteen in the thirds.
Green glass is another of these species, and which is greatly in demand for
all the purposes in which colour is not so particularly sought for. This sort of
glass is used in the glazing of the windows of cottages, also for green and hot-
houses, to which it is found to answer every purpose: it is not more than one-
half the cost of the crown glass. The green glass appears to have been the most
ancient kind made use of, as most of the vestiges remaining in the old win-
dows approach very nearly in their quality to what is now sold under that
designation. The glaziers also prepare the crown glass so as to produce an
opaque effect, to prevent the inconvenience of being overlooked; it is technically
called ground glass, which is not improper, inasmuch as it is rendered opaque
by rubbing away the polish from off its surface, to do which the glazier takes
care to have the sheets or panes of glass brought to their proper size; then they
are laid down smoothly as well as firm, either on sand or any other substance
which is adapted to admit of its lying securely; he then rubs it with sand and
water, or emery, till the polish be completely removed; it is then washed,
dried, and stopped into the window for which it was prepared. There was a
species of glass made at Venice originally, which was manufactured wholly for
this purpose, and is now to be seen in many counting-houses and old buildings;
its general appearance presented an uneven surface, appearing as though indented
all over with wires, leaving the intervening shapes in the form of lozenges. This
glass was very thick and strong, and is of the description known as plate glass;
it is now, however, generally substituted by the ground crown glass. A very
beautiful plate glass is manufactured by the British Plate-Glass Company, at
Ravenscroft, in Lancashire, and at their depôt in Albion-place, London, plates
of every size, up to those of very great dimensions, may be obtained, the
thickness varying from an eighth to a quarter of an inch. The cheapest kind
of glazing is the old fashioned mode, in small squares of the diamond or
644 GLOBES.
rhombus shape, technically called quarries, which are fixed in rebated leaden
bars in outbuildings, cottages and in some kind of church windows. The
lead for this purpose is cast and drawn through an instrument called a glazier's
vice, which gives it the exact form required, and perfects the grooves for the
reception of the quarries. These leads being cut to the proper lengths, they
are soldered together at the intersections. This metal, which is used instead of
the cross bars of sashes, is so soft as to be easily bent where the groove is left
in it for the glass, and to be bent up again to inclose the glass after it is in-
serted. Window lights of this kind are further strengthened by vertical or
horizontal bars of iron or wood, secured to them by bands of lead twisted
around the bar. Glaziers now cut all their glass with a diamond; whereas,
formerly, an instrument was made use of for the purpose, called a grozing-iron.
The diamond used by glaziers is left in its natural state, or with its outward
coat; when polished, it is said to lose its property, making a perfect fracture of
the glass; it is fixed in lead, and secured by a ferrule in a handle of hard wood,
and is used by drawing the diamond point over the glass, straight lines being
effected by the assistance of a straight edge, also of hard wood. The other
tools used by the glazier chiefly consist in “stopping-knives,” for spreading
the putty over the edges of the glass and rebates of the frames; in “hacking-
out tools,” which are strong-backed knives, capable of bearing the blows of a
hammer, and used in clearing out the old putty, or making repairs; also in a
pair of compasses, a three-foot rule, and a few other common tools, the uses of
which require no explanation. New sashes should always be primed, that is
painted once over before they are glazed, as the putty thereby holds much more
firmly to the work.
GLOBE, or SPHERE, in Geometry, a solid figure described by the revolution
of a semicircle round its diameter, which remains unmoved; or it may be
defined as a solid, bounded by a uniform convex surface, which is in every part
equally distant from a point called the centre.
GLOBE, in Practical Mathematics, an artificial sphere, on which are repre-
sented the countries and seas of our earth, or the face of the heavens, the circles
of the sphere, &c. That with the parts of the earth delineated upon it is
called the “Terrestrial Globe,” and that with the constellations of the heavens,
the “Celestial Globe.” These globes are mounted on frames with other appur-
tenances. Their principal use, besides serving as maps to distinguish the out-
ward parts of the earth, and the situation of the fixed stars, is to illustrate the
various phenomena arising out of the diurnal motion of the earth. The globes
commonly used are constructed of plaster and paper in the following manner:
a wooden axis is provided somewhat less than the intended diameter of the
globe, and into the extremities iron wires are driven for poles; on this axis are
applied two hemispherical caps, formed on a spherical wooden mould by pasting
several sheets of paper on the mould one over the other to about the thickness
of a crown piece, and cutting them through the middle when they are dried,
and slipping them off the mould. They are now applied to the poles of the
axis, and the two edges are sewed together with packthread. The rudiments
of the globe thus laid, they proceed to strengthen it and make it regular. In
order to do this the two poles are hasped in a metallic semicircle of the size
intended, and a plaster made of whiting, water, and glue, well incorporated
together, is daubed all over the surface; in proportion as the plaster is applied,
the ball is turned round in the semicircle, the edge of which pares off whatever
is superfluous, and beyond the due dimensions, leaving the rest adhering in
places that are short of it; the ball is then set to dry, after which it is again
set in the semicircle, and fresh plaster applied; and thus they continue to
apply fresh composition, and to dry it, .# the ball every where accurately
touches the semicircle, in which state it is perfectly smooth and regular. The
next thing is to paste the map on it: in order to this the map is projected in
several gores or gussets, all of which join accurately on the surface, and cover
the whole ball. To direct the application of these gores, lines are drawn by a
semicircle on the surface of the ball, dividing it into a number of equal parts,
corresponding to the number of gores, and subdividing those again answerably
GLOBES. 645
to those of the gores. The paper thus pasted on, there remains nothing but
to colour and illuminate the globe, and to varnish it, the better to resist dirt
and moisture. The globe itself thus finished, is suspended in a brass meridian
with an hour circle and a quadrant of altitude, and then fitted into a wooden
horizon, which is supported by the legs of the frame.
Major Muller, G.L. has contrived a new arrangement of the globes, to which
he has given the name of the cosmophere, and which forms the subject of the
annexed engraving. The celestial globe consists of a hollow glass sphere, on
º-cº
WEA
5-
º-3
E-
§º-
WH
- -- --
-º-º-º-º: tº sº
s::=>tº:r Nº.:
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which are depicted the stars constituting the various constellations. This sphere
is furnished with brass circles, representing the equinoctial, the ecliptic, the
N

646 GLUE.
colures, and the polar circles. The glass sphere separates at the equinoctial into
two hemispheres, for the purpose of admitting within it a terrestrial globe,
which is manufactured in the usual way: this globe is also furnished with
brass circles, which are adjustable, to represent at pleasure the meridian and
the horizon of any assigned place. The axis of the globe passes through the
sphere, and supports both in a strong brass ring, which may be either attached
to a stand, and made to rest upon a table, or suspended from the ceiling of a
room, with a counterpoise w, as represented in the engraving, which will render
the construction clear when compared with the following references, a a
represents the equinoctials, where the two hemispherical glasses g g are united,
and from which the declination of the stars is to be measured; c represents one
of the colures, and f one of the terrestrial meridians; h one of the polar cir-
cles, and m m the large brass circle or general meridian, in which the apparatus
is suspended by the poles N and S. By the cosmosphere, as we have described
it, the position of the earth, with respect to the fixed stars, may be shown at
any given time; and by placing on the celestial sphere patches to represent
portions of the sun, moon, and planets, the position of the earth with respect
to these bodies may also be represented with facility; hence many of the
astronomical phenomena arising from the position of the earth, with regard to
the other bodies, can be familiarly illustrated, and numerous useful problems
readily solved. But to extend its usefulness, the patentee has made arrange-
ments for removing the globe from the interior of the system, and placing in its
stead the sun and planetary system; and by this means the relative positions
of the planetary bodies may be interestingly represented. He has likewise pro-
vided brass graduated circles, by which, when they are attached to the celestial
sphere, the nature of the various astronomical and nautical problems depending
upon spherical trigonometry may be pleasingly explained.
GLUE. A tenacious viscid substance, used chiefly for binding or cementing
pieces of wood together: it is usually prepared from the cuttings and parings
of hides, and from the hoofs and horns of animals. For this purpose the
materials are first steeped in water for two or three days, then well washed, and
afterwards boiled to the consistence of a thick jelly, which is passed, while hot,
through ozier baskets, to separate the grosser particles of dirt, bones, &c. from it,
and then allowed to stand some time to purify it farther; when the remaining
impurities have settled at the bottom, it is then melted and boiled a second
time. It is next poured into flat frames or moulds, from which it is taken out
pretty hard and solid, and cut into square pieces or cakes, and afterwards dried
in the wind in a coarse kind of net. This is the ordinary method of preparing
the common glue for carpenters' work; but some few years back Mr. Yardley,
of Camberwei, obtained a patent for manufacturing glue from bones, which,
as chemists have long known, contain nearly one-half their weight of solid
gelatin, besides a considerable portion of fat. The glue thus obtained is said
to be of very superior quality.
In the engraving on the next page a represents a section of the principal vessel
of Mr. Yardley's apparatus, which is in the shape of a sphere or hollow globe of
great magnitude, and made of cast or wrought iron; copper should not be
used, as gelatin has a powerful action upon that metal. The first part of the
process is to cleanse the bones by immersing them in a pit or cistern of water,
where they are to remain about twelve hours; the water is then to be drawn
off, and fresh water added to them; this operation may be repeated several
times, to get rid of the adhering dirt. The water being withdrawn from the
bones, a solution of lime, in the proportion of one bushel of the earth to five
hundred gallons of water, is to be poured into the cistern for the more perfect
cleansing of the bones, and the removal of superfluous matters. After three or
four days' saturation the Yimy solution should be drawn off, and fresh water
added, to get rid of the lime. Thus prepared, the bones are brought to the
globular vessel a called the extractor, which is filled with them by removing
the interior plate which covers the man-hole b ; this aperture is of an elliptical
form, and allows the plate (which is of a similar figure) to be slipped round and
refixed in its place by turning the nut c, which draws it up tight against the
GLUE. 647
interior surface of the globular extractor; and the junctures are made air-tight
by luting. The extractor turns upon a horizontal cylindrical shaft in the bear-
ings e e : one-half of this shaft is made hollow, or consists of a strong tube ff.
which tube also proceeds downwards from the centre of the vessel, to conduct
the steam beneath the grating g, upon which the bones are laid. The steam, of
about 15 lbs. pressure to the inch, is admitted from the boiler by turning the
cock h, and, passing along the pipe by the safety valve i and the stuffing box
k, it enters and proceeds first to the bottom of the extractor, then rises up
through the grating, and amongst the bones, until the vessel is completely
charged; previous to this, however, the air contained in the vessel is got rid of
by opening the cock l for the steam to blow through, and afterwards closing it.
Whilst the steam is acting upon the bones the extractor is occasionally turned gently
round by hand at the winch m, the shaft of which carries a small pinion that takes
into the teeth of the wheel n, and the latter being on the same shaft as the
extractor, consequently gives it a rotatory motion. When at rest, as shown, a
quantity of fluid gelatin is collected in the bottom of the extractor at 0, from
whence it is discharged by the cock p into a tub beneath, after opening the air-
cock l to allow it to run off. This done, steam is again admitted from the
boiler into the extractor to act upon the bones for another hour, when the
second portion of condensed liquor is to be drawn off. When the products thus
obtained have become cold, the fat which has formed upon the surface is to be
carefully removed by skimming, and the gelatinous portion only is to be returned
into the extractor, by means of a funnel at the cock l. The steam is then re-
admitted to the extractor for another hour, after which it is finally drawn off into
another vessel to undergo a simple evaporating process, until it arrives at a
proper consistency to solidify when cold, previous to which some alum is added
to clarify it. When the gelatin has become cold and solid, it is cut out into
square cakes, and dried as usual in the open air. g
Mr. Bevan found that when two cylinders of dry ash, 1% inch in diameter, were
glued together, and, after twenty-four hours, torn asunder, it required a force of
1260lbs. for that purpose, and consequently that the force of adhesion was

648 GOLD BEATERS’ SKIN.
equal to 715 per square inch of surface. From a subsequent experiment on
solid glue, he found that the cohesion is equal to 4000lbs. on the square inch,
and hence infers, that the application of this substance as a cement is suscep-
tible of improvement. Glue is frequently prepared for more delicate purposes
in the arts from parchment or vellum cuttings, or from isinglass., Parchment
glue is made by boiling gently shreds of parchment in water, in the proportion
of one pound of the former to six quarts of the latter, till it be reduced to one
quart. The fluid is then strained from the dregs, and afterwards boiled to the
consistence of glue. Isinglass glue is made in the same way; but this is im-
proved by dissolving the isinglass in common spirit by a gentle heat: thus
prepared, it forms a cement much superior to paste for joining paper, or for
stretching it on wood.
GLUTEN. A substance found combined with the feculent and saccharine
matter, which constitute the principal part of nutritive grain. It is obtained in
the largest quantity from wheat (amounting to the twelfth part of the whole
grain) by kneading the flour into paste, which is to be washed very cautiously
by kneading it under a jet of cold water till the water carries off nothing more,
but remains colourless; what remains is gluten: it is ductile and elastic, and
has some resemblance to animal tendon.
GOLD. A yellow metal of specific gravity 19.3, which is greater than any
other body in nature, except platina. It is soft, very tough, ductile, and
malleable, unalterable and fixed, whether in the atmosphere or in the heat of
the hottest furnaces; but it has been volatilized by powerful burning mirrors,
as also by the oxy-hydrogen blow pipe. No acid acts readily upon gold, except
the nitro-muriatic acid, called aqua regia, in which it may be dissolved, occa-
sioning at the same time an effervescence; but from the slight affinity of gold
for oxygen, it is precipitated from its solvent by the alkalies, earths, and most
of the other metals. Its precipitate with ammonia forms a compound, which
detonates with great violence, as has been already mentioned under the article
FULMINATING Powders. Most metals combine with gold, increasing its hard-
ness, but considerably impairing its ductility. For the purposes of coin,
Mr. Hatchett considers an alloy of silver and copper in equal parts to be
preferred, and copper alone as preferable to silver only : but the gold coins of
Great Britain are composed of eleven parts of gold, and one of copper. Gold
is mostly found in the metallic state, although generally combined with silver,
copper, or iron, or all three. It is found either in separate lumps or visible
grains amongst the sands of rivers, in many parts of Europe, and elsewhere.
The quantity is for the most part insufficient to pay the expense of separating
it; but it is thought to be more universally diffused in sands and earth than
any other metal, except iron. Some sands afford gold by simple washing, the
heavy metallic particles subsiding first; but when it is imbedded in earths and
stones, these substances are first pounded, and then boiled with one tenth of
their weight of mercury, together with water. The mercury after a certain
time forms an amalgam with the gold, from which it is separated by pressure
through leather bags, and subsequent distillation. Gold is seldom used for
any purpose in a state of perfect purity. In estimating its fineness, the whole
mass spoken of is supposed to weigh 24 carats, of 12 grains each, and the pure
gold is called fine. Thus, if gold is said to be 23 carats fine, it is understood
that the mass consists of 23, parts of fine gold, and one part of alloy. The
principal use of gold is to make coin, trinkets, gold leaf for gilding, and gold
wire and thread.
GOLD-BEATERS’ SKIN.—The gold-beaters use three kinds of membranes,
viz. for the outside cover common parchment, made of sheepskins, is used; for
interlaying with the gold, first the smoothest and closest vellum, made of calves'
skin; and afterwards the much finer skins of ox-gut, stript off from the large
straight gut slit open, curiously prepared for the express purpose, and hence
called gold-beaters' skin. According to Dr. Lewis, the preparation of these
last is a distinct business, practised only by two or three persons in the kingdom.
The general process is supposed to consist in applying them one upon another,
by the smooth sides, in a moist state, in which they readily cohere and inite
GOLD WIRE, {549
inseparably, stretching them very carefully on a frame, scraping off the fat and
rough matter, so as to leave only the fine exterior membrane of the intestine,
at the same time beating them between double leaves of paper, to force out
what grease may remain in them, and then drying and pressing them. Not-
withstanding the vast extent to which gold is beaten between these skins, and
the great tenacity of the skins themselves, they yet sustain continual repeti-
tions of the process for several months, without appearing to extend or grow
thinner.
GOLD-BEATING. The gold is prepared for leaves by melting it in a
blacklead crucible, with some borax, in a wind furnace; and as soon as it is in
perfect fusion, it is poured out into an iron ingot mould, then forged and
passed between steel rollers, until they become long ribbons, as thin as
writing paper: each of these ribbons is then cut into 150 pieces, and each of
these pieces is next forged upon an anvil, till it is about an inch square.
These squares, which weigh 6; grains each, and are about # part of an inch
thick, are now well annealed, preparatory to the next operation, which consists
in interlaying the plates of gold alternately with pieces of very fine vellum,
about four inches square, and about twenty vellum leaves are placed on the
outsides; the whole is then put into a case of parchment, over which is drawn
another similar case, so that the packet is kept tight and close on all sides.
It is now laid on a smooth block of marble or metal, of great weight, and the
workman begins the beating with a roundfaced hammer, weighing sixteen
pounds; the packet is turned occasionally upside down, and beaten till the
gold is extended nearly to an equality with the vellum leaves. The packet is
then taken to pieces, and each leaf of gold is divided into four, with a steel
knife, having a smooth but not very acute edge. The 600 pieces thus produced
are interlaid with pieces of animal membrane, (see GoLDBEATERs’ Skin,) from
the intestines of the ox, of the same dimensions and in the same manner as the
wellum. The beating is continued, but with a hammer weighing only twelve
pounds, till the gold is brought to the same dimensions as the interposed mem-
brane. It is now again divided into four, by means of a piece of cane, cut to an
edge, the leaves being by this time so thin, that any accidental moisture conden-
sing on an iron blade, would cause them to adhere to it. The 2400 leaves hence
resulting are parted into three packets, with interposed membrane as before, and
beaten with the finishing hammer, weighing about ten pounds, till they acquire
an extent equal to the former. The packets are now taken to pieces, and the
gold leaves, by means of a cane instrument and the breath, are laid flat on a
cushion of leather, and cut one by one to an even square, by a little square
frame, made of cane; they are lastly laid in books of twenty-five leaves each,
the paper of which is previously smoothed, and rubbed with red bole, to
keep the gold from adhering. By the weight and measure of the best
wrought leaf-gold, it is found that one grain is made to cover 56% square inches;
and from the specific gravity of the metal, together with this admeasurement,
it follows that the leaf itself is #; part of an inch thick. This, however, is
not the limit of the extensibility of the metal; for by computing the surface
covered in silver gilt wire, and the quantity of gold used, it is found to be only
one-twelfth that of the gold leaf, or sº, part of an inch thick; nevertheless
it is so perfect as to exhibit no cracks when viewed by a microscope.
GOLD THREAD, as it is called, consists of a silk thread covered with gold
wire. It is formed by passing gold wire between two rollers of nicely polished
steel, set very close together, by which means it is rendered quite flat, but
without losing any thing of its polish or gilding, and becomes so exceeding!
thin and flexible that it is easily spun upon a silk thread, by means of a .
wheel, and so wound upon a spool or bobbin.
GOLD WIRE. That which is commonly called gold wire is in fact merely
silver wire gilt. The following is the proeess employed for this purpose.
First an ingot of silver of 24 pounds is forged into a cylinder of about an inch
in diameter, which is reduced by passing it through eight or ten holes of a
large coarse drawing iron, to about three fourths of its former diameter. It is
tiven filed very carefully all over, to remove any dirt from the forge, and after-

650 GRAVITY
wards cut through the middle into two ingots, each about 26 inches long, which
are drawn through several new holes to remove any inequalities left by the file,
and to render the surface as smooth and equable as possible. The ingot thus
far prepared, it is heated in a charcoal fire: then taking some gold leaves,
each about four inches square, and weighing 12 grains each, four, eight,
twelve, or sixteen of them are joined, as the wire is intended to be more or less
gilt, and when they are joined so as to form a single leaf, the ingots are rubbed
reeking hot with a burnisher, and the leaves applied over the whole surface of
the ingot to the number of six over each other, well burnished or rubbed
down. When gilt, the ingots are again laid in a charcoal fire, and raised to
a certain degree of heat, when they are gone over a second time with the bur-
nisher, both to solder the gold more perfectly, and to finish the polishing. The
gilding finished, the ingot is passed through twenty holes of a moderate draw-
ing iron, by which it is reduced to the thickness of the tag of a lace; from this
time the ingot loses its name, and commences gold wire. Twenty holes more
of a lesser iron leaves it small enough for the least iron, the finest holes of which
last, scarcely exceeding the hair of the head, finish the work. Each time that
the wire is drawn through a fresh hole it is rubbed afresh with new wax, both
to facilitate its passage, and to prevent the silver appearing through it.
GONIOMETER. An instrument for measuring the angles formed by two
or more planes, and chiefly, in crystallography, to determine the angles of
crystalline substances.
GOUGE. A sort of round hollow chisel, for cutting holes, channels, grooves,
&c. in wood or stone.
GRANARY. A storehouse for grain. The construction of this class of
buildings has not, we believe, received that attention from the scientific which
the importance of it deserves. The best which we have met with in print con-
sists º a plain rectangular building, about twice the height of the distance
between the opposite walls, that is 20 feet high by 10 feet in width on each
side, and provided with numerous air-holes, declining outwards, to prevent the
entrance of rain or snow; from each air-hole to a corresponding one on the
opposite side is fixed an inverted angular spout or gutter, which permits the
air to pass through unimpeded by the corn lying above it. As many of these
gutters are fixed, as there are holes to receive the ends after crossing the build-
ing; and the extremities of the holes are covered with wire gauze, to defend
them from vermin. The first floor of the granary is divided into a series of hop-
pers, that empty themselves into one large hopper underneath, provided with a
sliding door to regulate the passage of the grain into a sack or other receptacle.
At the top of the building is a loft, to which the corn is first hoisted by a tackle
or crane, and is discharged over a cross bar into the body of the building, which
may be continued until it is filled to the top. Upon drawing off any corn at the
bottom, the whole of it is put into motion, and the airing of every part is pro-
moted; the process of airing is however continually going forward through the
numerous passages under the inverted gutters, the angles of which, it is said,
do not fill up by the lateral pressure of the grain.
GRANULATION. The method of dividing metallic substances into grains
or small particles to facilitate their combination with other substances, and
sometimes for the purpose of readily subdividing them by weight. This is
done either by pouring the melted metal into water, or by agitating it in a box,
until the moment of congelation, at which instant it becomes converted into a
powder. Copper is granulated for making brass by pouring it through a per-
forated ladle into a covered vessel of water, with a movable false bottom.
The small shot made of an alloy of lead with arsenic is produced in like manner,
by pouring the liquid metal through a perforated colander, and allowing it to
fall from a considerable elevation through the air, which causes the drops to
assume a spherical shape. See SHOT, SoldeR, &c.
GRAVITY, in Physics, the natural tendency of bodies towards a centre.
Terrestrial or particular gravity is that by which bodies descend or tend towards
the centre of the earth; the phenomena of which are as follows:–1. All
circumterrestrial bodies tend towards a point which is either accurately or nearly
GRAVITY. 651
the centre of magnitude of the terraqueous globe. 2. In all places equidistant
from the centre of the earth the force of gravity, cateris paribus, is equal. The
force of gravity is not equal on all parts of the earth's surface for two reasons;
first, because, as the earth is not a sphere, but a spheroid, all parts of its surface
are not equidistant from its centre; and secondly, the gravity is different in
different latitudes, by reason of variations in the centrifugal force, occasioned
by the earth's rotation, the increment of gravity on this account being as the
square of the cosine of the latitude. 3. Gravity affects equally all bodies,
without regard either to their bulk, figure, or matter; so that in a perfectly
unresisting medium, the most compact and the loosest, the greatest and the
smallest bodies would descend through an equal space in the same time. The
space through which bodies do actually fall in vacuo is 164 feet in the first
second of time in the latitude of London, and for other portions of time either
greater or less the spaces are as the squares of the times. 4. Gravity is greatest
at the earth's surface, from whence it decreases both upwards and downwards,
but not at the same ratio in each direction; the diminution of the force upwards
being as the square of the distance from the earth's centre; whilst downwards,
the decrease is in the direct ratio of the distance from the centre.
General, or Universal Gravity, is that in consequence of which all the planets
tend to one another; and indeed all the bodies and particles of matter in the
universe tend to one another.
Gravity, specific, is the relative gravity of any body or substance, considered
with regard to some other body which is assumed as a standard of comparison,
and this standard by universal consent and practice is rain water or distilled water,
and by a very fortunate coincidence, at least to English philosophers, it happens
that a cubic foot of water weighs 1000 ounces avoirdupoise, and consequently
assuming this as the specific gravity of rain water, and comparing all other
bodies with this, the same numbers that express the specific gravity of bodies
will at the same time denote the weight of a cubic foot of such bodies in avoir-
dupoise ounces. From the preceding definition may be drawn the following
laws of the specific gravity of bodies. 1. In bodies of equal magnitudes, the
specific gravities are directly as the densities, or as their weights. 2. In bodies
of the same specific gravities, the weights will be as the magnitudes. 3. In
bodies of equal weights, the specific gravities are inversely as the magnitudes.
4. The weights of different bodies are to each other in a compound ratio of
their magnitudes and specific gravities. 5. When a body is specifically heavier
than a fluid it loses as much of its weight when immersed in it as is equal to
the weight of a quantity of the same fluid of equal bulk. , 6. If the gravity
of the fluid be greater than that of the body, then the weight of the quantity
of fluid displaced by the part immerged, is equal to the weight of the whole
body. The specific gravity of solid bodies is usually determined experimentally
by means of the “Hydrostatic Balance,” (See BALANCE;) but for —f
ascertaining the specific gravity of liquids, an instrument termed (,
a “Hydrometer” is usually employed. A description of a variety
of these instruments will be found under the head HYDROMETER.
The late Professor Leslie invented a new and singularly simple
and ingenious method for ascertaining the specific gravity of b
solids. All substances of this class are more or less porous; and r
the pores being filled with air which is not expelled when the sub-
stance is immersed in water causes their specific gravity when ascer-
tained by the hydrostratic balance to appear less than it really is.
In Mr. Leslie's method this source of error is avoided, and some of
the results obtained in consequence are extremely curious. The
instrument employed consists of a glass tube a c, about three feet
long, and open at both ends; the wide part a b is about four-
tenths of an inch in diameter; the part b c about two-tenths.
The two parts communicate at b by an extremely fine slit, which
suffers air to pass, but retains sand or powder. The mouth at a G
is ground smooth, and can be shut so as to be air-tight by a small
glass plate f. The substance whose specific gravity we wish to find is first

652 GRENADE.
reduced to powder, which is then put into the wide part of the tube a b, which
may either be filled or not. The tube being then held in a vertical position
has the narrow part immersed in mercury, contained in an open vessel w,
till the metal rises within to the gorge b. The lid is then fitted on air-tight
at a. In this state it is evident there is no air in the tube, except that
mixed with the powder in the cavity a b. Suppose the barometer at the
time to stand at 30 inches, and that the tube is lifted perpendicularly upwards,
till the mercury stands in the inside of b c, at a point e 15 inches, (or one half of
30,) above its surface, in the open vessel; it is evident, then, that the air in
the inside of the tube is subjected to a pressure of exactly half an atmosphere:
and of course it dilates and fills precisely twice the space it originally occupied.
It follows, too, that since the air is dilated to twice its bulk the cavity ab contains
just half what it did at first; and the cavity be now containing the other half,
the quantity of air in each of these parts of the tube is equal. In other words,
the quantity of air in be is exactly equal to what is mixed with the powder in
a b, and occupies precisely the same space which the whole occupied before its
dilatation. Let us now suppose the powder to be taken out, and the same expe-
riment repeated, but with this difference, that the cavity a b is filled with air
only. It is obvious that the quantity being greater it will, when dilated to
double the bulk under a pressure of fifteen inches, occupy a larger space, and
the mercury will rise, let us suppose, only to d. But the attenuated air in the
narrow tube always occupies exactly the space which the whole occupied at
ordinary atmospheric pressure; and this space is therefore, in the one case, the
cavity be, and in the other b d. Hence it follows that the cavity ed, which is
the difference between these, is equal to the bulk of the solid matter in the
sand. Now by marking the number of grains of water held by the narrow
tube be on a graduated scale attached to it, we can find at once what is the
weight of a quantity of water, equal in bulk to the solid matter in the sand;
and by comparing this with the weight of the sand, we have its true specific
gravity. Aware that some solid bodies, such as charcoal, hold much condensed
air in their pores, and that probably they retain part of this even when reduced
to powder, Professor Leslie obviates the chances of error arising from this
source by comparing the dilatation which takes place under different degrees
of pressure, under 10 inches and 20 for instance, or 7} and 15. Charcoal, from
its porosity, is so light that its specific gravity, as assigned in books, is generally
under 0.5 less than half the weight of water, or one seventh the weight of
diamond; taken in powder by the above instrument it exceeds that of diamond,
is one half greater than that of whinstone, and is, of course, more than seven
times heavier than has usually been supposed. Mahogany is generally estimated
at 1.36; but mahogany sawdust proves by the instrument to be 1.68; wheat
flour is 1.46; pounded sugar 1.83; and common salt 2.15; the last agrees very
accurately with the common estimate. Writing paper rolled hard by the hand
had a specific gravity of 1.78, the solid matter present being less than one third
of the space it apparently filled. One of the most remarkable results was with
an apparently very light specimen of volcanic ashes, which was found to have
a specific gravity of 4.4. These results are, however, given as approximations
merely by the first instrument constructed.
GRENADE. A kind of small bomb or shell filled with an explosive com-
position, and fired by a fusee inserted in the touch-hole. Their principal use is
in a close assault, when they are thrown by hand from the tops of ships or
ramparts of fortresses, whence they are frequently styled hand grenades. They
are usually about three inches in diameter, and weigh about three pounds.
Their employment in war is not so general as formerly,
owing partly to the uncertain action of the fusee, which ren-
ders it difficult to ensure their explosion so as to produce the
greatest effect. To obviate this defect, grenades have been
invented which are fired by means of a cap containing a
priming of percussion powder instead of a lighted fusee.
The annexed engraving represents a section of a grenade
upon this principle. a the shell of cast-iron supposed to be

GUM. 653
filled with combustible matter, and having a conical hole into which an iron
pin, surrounded by a piece of cork, fits easily; the other extremity of the pin
is formed to receive a percussion cap, in which is put a small quantity of per-
cussion powder. The shell being thrown, it will naturally fall on the head of
the pin projecting on the outside; the detonating powder is kindled by the
blow, and the contents of the shell, as well as the shell itself, are scattered in
all directions.
The annexed engraving represents a percussion
hand grenade, invented by Capt. Norton of the
34th Regiment. Its construction is precisely the
same as that of the foregoing one, but there is in
addition a sheet of brown paper, or a piece of
common cloth tied to a button, on the outside of
the shell, forming a handle to throw it by, and
guiding its descent, so that the head of the bolt
will infallibly strike the ground, and thereby insure
the explosion.
GRINDING. A mechanical process, in which
certain effects are produced by the attrition of two
surfaces. The process of grinding is of extensive
use in various mechanical arts; and great diffe-
rences exist in the mode of conducting it according
to the purposes for which it is employed, which are very varied; thus, in grinding
corn, the object is to reduce the grain to an impalpable powder; in grinding
lenses, it is to give them a certain figure and polish; cocks and valves are
ground into their seats to promote intimate contact; colours are ground to
promote the intimate mixture of the colouring matter with the oil; and cutlery
and tools are ground, to impart to them a sharp edge. The latter operation,
as is well known, is performed by applying the articles to be ground to the
periphery of a cylindrical stone of a rough, gritty texture, revolving with great
rapidity; and to reduce as much as possible the heat caused by the friction of
the two surfaces, the stone is mounted over a trough containing water. Some
curious experiments are detailed in Nicholson's Journal upon this point, from
which it appears that tallow is much more effective than water in keeping the
temperature low ; for in trying to grind down the teeth of a file with the grind-
stone immersed in water, the file soon became too hot to hold, and the teeth
were scarcely touched, but by applying a tallow candle to a dry grindstone as
it revolved, so as to give an even coating of tallow, he was enabled to grind
down the teeth rapidly, and the temperature of the file was scarcely raised until
the tallow became melted. This effect Mr. Nicholson attributes to the heat
absorbed or rendered latent in bringing a solid substance into a fluid state.
GRINDSTONE. A flat circular stone, mounted on a spindle, and turned
by a winch handle, used for the purpose of grinding edge tools. In districts
where cutlery and edge tools are manufactured, great numbers of these stones
are used in one building, called a blade mill or grind mill. The stone suited
to form grindstones is composed of a coarse species of sandstone. The finer
sorts of grindstones, and what are called whitening or polishing stones, by the
Sheffield cutlers, are from different rocks in the upper part of the great Derby-
shire Coal Series; others are from Staffordshire, Warwickshire, &c.
GUITAR. A musical instrument with five double rows of strings, of which
those that are bass are in the middle.
GUM. . A vegetable juice, or thick, transparent, tasteless fluid, which some-
times exudes from certain species of trees. It is very adhesive, and gradually
hardens without losing its transparency; but easily softens again when mois-
tened with water. The gum most commonly used is that which is procured
from different species of the Acacia in Egypt, Arabia, &c.; it is known by
the name of gum arabic. Gum likewise exudes abundantly from the common
wild cherry tree of this country: it exists also in various plants in the state of
mucilage, especially in the roots and leaves. It is most abundant in bulbous roots;
and of these, the hyacinth affords the largest quantity. Gum readily dissolves

4 o
651. 5
GUN.
in water, and the solution, which is thick and adhesive, is known by the name
of mucilage. It is also soluble in the vegetable acids, but is decomposed by the
sulphuric, nitric, and muriatic acids. It is insoluble in alcohol and ether.
GUN. A fire-arm or weapon chiefly composed of a barrel or long tube,
from which shot and other missiles are discharged by means of inflamed gun-
powder; ignition being effected by the percussion of flint and steel, or that of
detonating powder, through the instrumentality of a piece of mechanism called
the lock, which is fixed to the handle or stock, and in connexion with the lower
extremity of the barrel, where the charge is deposited. The word gun, how-
ever, is indiscriminately applied to almost every species of fire-arm, and is
usually divided into two classes, namely, great guns, and small arms. The
former include cannon, artillery, and various species of ordnance, that are
moved on wheels, pivots, trucks, and slides, which are described under their
separate heads; the latter class, which embraces muskets, blunderbusses, car-
bines, fowling-pieces, and pistols, being such as are manufactured by gun-smiths,
we propose to describe in this place.
The principal parts of a gun are the barrel, the lock, and the stock. The
following are the requisite properties of the barrel:—first, lightness, that it may
incommode the person who carries it as little as possible; secondly, sufficient
strength, and other properties requisite to prevent its bursting by a discharge ;
thirdly, it should be constructed in such a manner as not to recoil with violence;
and fourthly, it should be of sufficient length to carry the shot to as great a
distance as the force of the powder employed is capable of doing. The best
barrels in this country are formed of stubs, as they are called, or old pieces of
horse-shoe nails. About twenty-eight pounds of these are requisite to form a
single musket barrel. The method of manufacturing them from this material
is as follows:—a hoop of about an inch broad, and six or seven inches diameter,
is placed in a perpendicular position, and the stubs, previously well cleaned,
piled up in it with their heads outermost on each side, till the hoop is quite
filled and wedged tight with them. The whole then resembles a rough circular
cake of iron, which being heated to a white heat, and then strongly hammered,
unite into one solid lump. The hoop is now removed, and the heatings and
hammerings repeated till the iron is rendered very tough and close in the grain,
when it is drawn out into pieces of about twenty-four inches in length, half an
inch or more in breadth, and half an inch in thickness. Four of the pieces, pre-
pared as has been described, are required for one barrel; but in the ordinary
way, a single bar of the best soft iron is employed. The workmen begin
with hammering out this into the form of a flat ruler, having its length and
breadth proportioned to the dimensions of the intended barrel. By repeated
heating and hammering, this plate is turned round a tempered iron rod called
a mandril, the diameter of which is considerably smaller than the intended bore
of the barrel. One of the edges of the plate being laid over the other about
half an inch, the whole is heated and welded by two or three inches at a time,
hammering it briskly, but with moderate strokes, upon an anvil, which has a
number of semicircular furrows in it, adapted to the barrels of different sizes.
Every time the barrel is withdrawn from the fire the workman strikes it gently
against the anvil once or twice in a horizontal direction. By this operation the
particles of the metal are more perfectly consolidated, and every appearance of
a seam in the barrel is obliterated. The mandril being then again introduced
into the cavity of the barrel, the latter is very strongly hammered upon it in
one of the semicircular hollows of the anvil by small portions at a time, the
heatings and hammerings being repeated until the whole barrel has undergone
the operation, and its parts rendered as perfectly continuous as if they had
been formed out of a solid piece. To effect this completely three welding heats
are necessary when the very best iron is made use of, and a greater number for
the coarser kinds.
The next operation in forming the barrels is the boring of them, which is
usually done in the following manner:—Two beams of oak, each about six
inches in diameter, and six or seven feet long, are placed horizontally, and
parallel to one another, having each of their extremities mortised upon a strong
GUN. 655.
upright piece about three feet high, and firmly fixed; a space of three or four
inches is left between the horizontal pieces, in which a piece of wood is made
to slide by having at either end a tenon let into a groove, which runs on the
inside of each beam throughout its whole length. Through this sliding piece
a strong pin or bolt of iron is driven or screwed in a perpendicular direction,
having at its upper end a round hole large enough to admit the breech of the
barrel, which is secured in it by means of a piece of iron that serves as a
wedge, and a vertical screw passing through the upper part of the hole. A
chain is fastened to a staple on one side of the sliding piece, which runs between
the two horizontal beams, and passing over a pulley at one end of the machine,
has a weight hooked on to it; an upright piece of timber is fixed above this
pulley and between the ends of the beams, having its upper end perforated by
the axis of an iron crank furnished with a square socket, the other axis being
supported by the wall, or by a strong post, and loaded with a heavy wheel of
cast-iron to give it force. The axes of this crank are in a line with the hole in
the bolt already mentioned. The borer being then fixed into the socket of the
crank, has its other end, previously well oiled, introduced into the barrel, whose
breech part is made fast in the hole of the bolt; the chain is then carried over
the pulley, and the weight hooked on ; the crank being then turned with the
hand, the barrel advances as the borer cuts its way till it has passed through
the whole length. The boring bit consists of an iron rod somewhat longer than
the barrel, one end of which fits the socket of the crank; the other is adapted
to a cylindrical piece of tempered steel, about an inch and a half in length,
having its surface cut after the manner of a perpetual screw, with five or six
threads, the obliquity of which is very small; the breadth of the furrows is the
same with that of the threads, and their depth sufficient to let the metal cut by
the threads pass through them easily; thus the bit gets a strong hold of the
metal, and the threads being sharp at the edges, scoop out and remove all
the inequalities and roughness from the inside of the barrel, and render the
cavity smooth and equal throughout. A number of bits, each a little larger
than the former, are afterwards successively passed through the barrel in the
same way, until the bore has acquired the magnitude intended. By this opera-
tion the barrel is very much heated, especially the first time the borer is passed
through it, by which means it is apt to warp : to prevent this in some measure,
the barrel is covered with a cloth kept constantly wetted, which not only pre-
serves the barrel from an excess of heat, but likewise preserves the temper of
the bit from being destroyed. The equality of the bore is of the utmost con-
sequence to the perfection of a barrel, insomuch that the greatest possible accu-
racy in every other respect will not make amends for any deficiency in this.
The method used by gunsmiths to ascertain this is by a cylindrical plug of
tempered steel highly polished, about an inch in length, and fitting the bore
exactly; this is screwed upon the end of an iron rod, and introduced into the
cavity of the barrel, where it is moved backwards and forwards; and the places
where it passes with difficulty being marked, the boring bit is repeatedly passed
until it moves with equal ease through every part. In forming the breech, a
tap is introduced into the barrel, and worked from left to right, and back again,
until it has marked out the first four threads of the screw ; another less conical
tap is introduced; and when this has carried the impression of the screw as far
as it is intended to go, a third one, nearly cylindrical, is made use of scarcely
differing from the plug of the breech intended to fill the screw thus formed in
the barrel; the plug itself has its screw formed by means of a screw plate of
tempered steel, with several female screws corresponding with the taps em-
ployed for forming that in the barrel. Seven or eight threads make a sufficient
length for a plug; they ought to be neat and sharp, so as completely to fill the
turns made in the barrel by the tap. The breech plug is then to be case-har-
dened, or to have its surface converted into steel by covering it with shavings
of horn, or the parings of the hoofs of horses, and keeping it for some time red
hot, after which it is plunged in cold water.
The above is the usual method of making the common barrels, especially for
fowling pieces; but there are some other methods of manufacture by which
656 GUN.
, they are thought to be considerably improved. One kind of these are called
twisted barrels, and by the English workmen are formed out of the plates made
of stubs, as above described. Four of these, of the size already mentioned,
are requisite to make one barrel; one of them heated red hot for five or six
inches, is turned like a cork-screw by means of the hammer and anvil, the
remaining parts being treated successively in the same manner until the whole
is turned into a spiral forming a tube, the diameter of which corresponds with
the bore of the intended barrel. Four are generally sufficient to form a barrel
of the ordinary length, that is from 32 to 38 inches; and the two which form
the breech or strongest part, called the reinforced part, are considerably thicker
than those which form the muzzle or fore part of the barrel: one of these tubes
is then welded to a part of the old barrel to serve as a handle; after which the
turns of the spiral are united by heating the tube two or three inches at a time
to a bright white heat, and striking the end of it several times against the
anvil in a horizontal direction with considerable force, which is called jumping
the barrel; and the heats given for this purpose are called jumping heats. The
next step is to introduce a mandril into the cavity, and to hammer the heated
portion lightly, in order to flatten the ridges or burrs raised by the jumping at
the place where the spirals are joined. As soon as one piece is jumped
throughout its whole length, another is welded to it and treated in the same
manner until the four pieces are united, when the part of the old barrel is cut
off as being no longer of any use. The welding is repeated three times at
least, and is performed exactly in the same manner as directed for plain
barrels; and the piece may afterwards be finished according to the directions
already given. The advantages of twisted barrels are, after all, somewhat pro-
blematical, where there is so much of welding; and that in a spiral form, the
welding is more likely to be done in a careless manner, or with some imper-
fection in some part, than when it is a plain, is an obvious business; nor have
we observed that twisted barrels are less liable to burst than plain ones, where
the latter have been well and carefully forged. The manufacture of rifle bar-
rels, in their first formation, is exactly similar to that of other barrels, except
that their external form is generally octagonal : instead of being smooth on the
inside, like the common pieces, they are formed with a number of spiral chan-
nels resembling those of a screw, except only that the threads or rifles are less
deflected, making only one turn, or a little more, in the whole length of the
piece. This construction of the barrel is employed for correcting the irregu-
larity in the flight of balls from smooth barrels. The rifle barrels which have
been made in England, where they are not very common, are contrived to be
charged at the breech, the piece being for this purpose made larger there than
in any other part; the powder and bullet are put in through the side of the
barrel by an opening, which, when the piece is loaded, is filled up with a screw;
by this means, when the piece is fired, the bullet is forced through the rifles,
and is projected with greater truth. The principal imperfections to which gun
barrels are liable are the chink, crack, and flaw; the first is a small rent in the
direction of the length of the barrel; the second across it; and the third is a
kind of scale or small plate adhering to the barrel by a narrow base, from
which it spreads out like the head of a nail from its shank, and, when sepa-
rated, leaves a pit or hollow in the metal. The chink or flaw are of much
worse consequence than the crack in fire-arms, the force of the powder being
exerted more upon the circumference than the length of the barrel. The flaw
is much more frequent than the chink, the latter scarcely ever occurring but in
plain barrels formed out of a single plate of iron, and then only when the
metal is deficient in quality: when flaws happen on the outside they are of no
great consequence; but in the inside they are apt to lodge moisture and foul-
ness, which corrode the iron, and thus the cavity enlarges continually till the
piece bursts. This accident, however, may arise from many other causes
besides the defect of the barrel itself; the best pieces will burst when the ball
is not sufficiently rammed home, so that a space is left behind it and the
powder; a very small windage or passage for the inflamed powder between the
sides of the barrel and ball will be sufficient to prevent the accident; but if
GUN. 657
the ball has been forcibly driven down with an iron ramrod, so as to fill up the
cavity of the barrel very exactly, the piece will almost certainly burst, if only
a very small place is left between it and the powder; and the greater the space
is, the more certainly does the event take place. A piece will undoubtedly burst
from having its mouth stopped up with earth or snow; which accident some-
times happens to sportsmen in leaping a ditch, in which they have assisted
themselves with their fowling-piece, putting the mouth of it to the ground;
and when this did not happen, it is only to be accounted for from the stoppage
being extremely slight. For the same reason, a musket will certainly burst if
it is fired with the muzzle immersed only a very little way in water; it will
also burst from an overcharge; but when such an accident happens in other
circumstances, it is most probably to be attributed to a defect in the workman-
ship, or in the iron itself. These defects are principally an imperfection in the
welding, a deep flaw having taken place, or an inequality in the bore; which
last is the most common of any, especially in the low priced barrels. The
reason of a barrel's bursting from the inequality of the bore is, that the elastic
fluid set loose by the inflammation of the powder, and endeavouring to expand
itself in every direction, being repelled by the stronger parts, acts with addi-
tional force against the weaker ones, and frequently bursts through them,
which it would not have done had the sides been equally thick and strong
throughout. With regard to defects arising from the bad quality of the iron,
it is impossible to say any thing certain, as the choice of the materials depends
entirely on the gunsmith. The only way to be assured of having a barrel made
of proper metal, is to purchase it of a manufacturer of known reputation, and
to give a liberal price for the piece.
The recoil of a gun becomes an object of importance only when it is very
great, for every piece recoils in some degree when it is discharged. The most
frequent cause of an excessive recoil is an inequality in the bore of the barrel;
and by this it will be occasioned even when the inequality is too small to be
perceived by the eye. The explanation of this upon mechanical principles,
indeed, is not very obvious; for as it is an invariable law that action and re-
action are equal to one another, we should be apt to suppose that every time a
piece is discharged it should recoil with the whole difference between the velo-
city of the bullet and that of the inflamed powder. The cause to which too
great a recoil in muskets has been usually attributed, is the placing of the
touch-hole at some distance from the breech-plug, so that the powder is fired
about the middle, or towards its fore part, rather than at its base; to avoid this,
a groove or channel is often made in the breech-plug as deep as the second or
third turn of the screw, the touch-hole opening into this channel, and thus
firing the powder at its very lowest part. It appears, however, from a number
of experiments made upon this subject by M. Le Clere, that it made very little
difference with regard to the recoil, whether the touch-hole was close to the
breech, or an inch distant from it. The only circumstance to be attended to
with respect to its situation, therefore, is, that it be not quite close to the breech-
plug, as in such a case it is found to be more apt to be choked up than when
laced about a quarter of an inch from it. It was formerly supposed, that the
i. gun barrels were made the greater would be the distance to which they
carried the shot, and that without any limitation. This opinion continued to
prevail till near a century ago, when it was first proposed as a doubt whether
long barrels carried further than short ones. Mr. Robins informs us, that “if
a musket barrel of the common length and bore is fired with a leaden bullet
and half its weight of powder, and if the same barrel is afterwards shortened
one-half, and fired with the same charge, the velocity of the bullet in this
shortened barrel will be about one-sixth less than what it was when the barrel
was entire; and if, instead of shortening the barrel, it is increased to twice its
usual length, when it will be near eight feet long, the velocity of the bullet will
not be augmented more than one-eighth part; and the greater the length of
the barrel is in proportion to the diameter of the bullet, and the smaller the
quantity of powder, the more inconsiderable will these alterations of velocity
be.” From these considerations it appears that the advantages gained by long
658 GUNPOWDER.
barrels are by no means equivalent to the disadvantages arising from the weight
and incumbrance of using them; and from a multitude of experiments, it is
now apparent that any one may choose what length he pleases without any
sensible detriment to the range of the piece. The most approved lengths are
from 30 to 36 inches. An opinion has generally prevailed among sportsmen,
that by some unknown manoeuvre the gunsmith is able to make a piece loaded
with small shot, throw the contents so close together, that even at the distance
of 40 or 50 paces the whole will be confined within the breadth of a hat. From
such experiments as have been made on this subject, however, it appears that
the closeness or wideness with which a piece throws its shot, is liable to in-
numerable variations from causes which no skill in the gunsmith can possibly
reach. So variable are these causes, that there is no possibility of making the
same piece throw its shot equally close twice successively. In general, how-
ever, the closer the wadding is the better disposed the shot seems to be to fall
within a small compass. In firing with small shot a curious circumstance
sometimes occurs, viz. that the grains, instead of being equally distributed
over the space they strike, are thrown in clusters of 10, 12, 15, or more;
whilst several considerable spaces are left without a grain in them. Sometimes
one-third or one-half of the charge will be collected into a cluster of this kind;
nay, sometimes, though much more rarely, the whole charge will be collected
into one mass, so as to pierce a board near an inch thick at the distance of 40 or
45 paces. Small barrels are said to be more liable to this clustering than large
ones; and M. de Marolles informs us that this is especially the case when the
barrels are new, and likewise when they are fresh washed; though he acknow-
ledges that it did not always happen with the barrels he employed, even after
they were washed. It is probable, therefore, that the closeness of the shot depends
on some circumstance relative to the wadding rather than to the mechanism of
the barrel.
The lock of the gun, which comes next to be considered, was originally only
a cleft piece of iron, moving on a pin fixed in a stock. To this succeeded the
wheel lock, so called from a small wheel of solid steel, which being let off by
a spring, by its rapid evolutions elicited fire from the flint, and ignited the
priming. This was superseded by the Snaplance, in which a motion was given
to the cock which held the flint, and a movable plate of steel called the frizel,
or hammer, was placed vertically above the pan to receive it. A great many
improvements in gun locks have been made during the last twenty or thirty
years, which have contributed to render this part of the gun admirably efficient.
Our space will not permit us to enter into details; we therefore refer the reader
to the periodical works descriptive of patent inventions. The important requi-
sites in a gun lock are, that the action of the cock be as rapid as possible, and
that it should be so placed, that on uncovering the pan the flint may point into
the centre of the priming, and as near to it as possible, without touching it;
the main spring should have a smooth and active motion; the hammer spring
should be light, and should give a slight resistance to the cock on its striking
the steel, which ought to move on a roller.
The stocks of guns have assumed a great variety of forms. Sportsmen's
guns, till within these thirty years, were made very crooked in the stock, and
no regard was then paid to the balance of the piece; since that period straight
stocks have been universally adopted, and the length of the stock has been
accommodated to the stature of the person for whom it is made.
GUNNERY.. The art of employing artillery and other fire-arms against an
enemy with the best effect, including every thing that is necessary to a com-
plete knowledge of the most approved methods of mounting, transporting,
charging, directing, discharging, &c. the above. It includes also a knowledge
of pyrotechny, the theory, force, and effect of gunpowder, the proportions of
powder and ball required to produce a proposed effect; and rules for computing
the range of the projectile, the elevation of the piece, &c.
GUNPOWDER. The origin of the invention of gunpowder is a question
upon which the learned are by no means agreed; some attributing it to
Schwartz, a German monk, in 1320, others to Roger Bacon, who lived nearly
GUNPOWDER, - 659
a hundred years prior to that date; whilst other writers again contend, and
with every appearance of probability, that the invention had its rise in the
East, and that it has been known to the Indians and Chinese for thousands of
years. The most improved proportions for the composition of gunpowder are
75 parts by weight of nitre, to 16 of charcoal, and 9 of sulphur, which being
separately reduced to a fine powder, are intimately blended together with a
small quantity of water. This operation was formerly performed in wooden
mortars, with wooden pestles; in the large way by means of a mill, wherein
the mortars were disposed in rows, and in each of the mortars a pestle was
moved by the arbor of a water wheel. The heat, however, produced by the
blows of the pestle, occasioned such frequent explosions, that an Act of Par-
liament was passed in the 12th of Geo. III. prohibiting their use, and limiting
the licenses to mills similar in principle to the one which we shall describe
towards the close of this article. The mixture is, from time to time, mois-
tened with water which serves to prevent its being dissipated in the pulverulent
form, and likewise obviates the danger of explosion. When the process of
blending the materials together in this manner is complete, (which requires
several hours,) the gunpowder is in fact made, and only requires to be dried, to
render it fit for use. The granulation of gunpowder is effected by placing the
mass, while in the form of a stiff paste, in a wire sieve, covering it with a
board, and agitating the whole; by the pressure of the board, it is thus cut
into small grains or parts. The powder is smoothed or glazed, as it is called,
for small arms, by the following operation : a hollow cylinder or cask is
mounted on an axis, and turned by means of a water-wheel or other power;
this cask is half filled with powder, and turned for six hours, and thus by the
mutual friction of the grains of powder, it is smoothed or glazed. The fine
mealy part thus separated from the rest is again granulated. The granulation
causes it to take fire more readily, as the inflammation is more speedily propa-
gated through the interstices of the grains. The variations in the strength of
different samples of gunpowder are generally owing to the more or less minute
division and intimate mixture of the parts; the reason of this may be easily
deduced from the consideration, that nitre does not detonate until in contact
with inflammable matter, consequently the whole detonation will be the more
speedy the more numerous the points of contact. For this reason also the
ingredients should be very pure, as the mixture of any foreign matter not only
diminishes the quantity of effective ingredients, but prevents their contact by
its interposition. The elastic product obtained by the detonation of gunpowder
was found by Berthollet to consist of two parts of nitrogen gas, and one part
of carbonic acid gas. The sudden extrication and expansion of these gases are
the cause of the effects of gunpowder. -
We shall now proceed to describe an improved gunpowder mill invented by
Mr. James Monk, the manager at the gunpowder mills of Messrs. Burton,
Children, and Burton, near Tunbridge. Some few years ago a model and descrip-
tion of it was presented to the Society of Arts, who voted to Mr. Monk their
silver medal and twenty guineas, as a mark of their sense of its merits. a a Fig. 1,
on the following page, is a compound lever, formed of two iron bars, the extre-
mities of which terminate above the bedstones of the pair of mills, A B; these
levers are connected at their other extremities by a bolt at b, forming a joint, and
permitting the levers to move so as to form a very obtuse angle, when a power
from below upwards is applied to either of the ends of the levers aa as shown by the
dotted lines. c c are two oblong holes in the lever bars, through which two screws
are put, which, being screwed into the two uprights, constitute the two fixed
fulcrums of the levers; d d are two uprights, with an eye or loop in each to
receive and steady the ends of the lever, which are made long enough to allow
the bars to take the position indicated by the dotted lines; ee are two blowers,
made of thin sheet iron, in the form of hollow three-sided pyramids, and are
suspended by two iron rods to the ends of the levers a a. These blowers are
placed as near as possible to the tops of the upright stone shafts, and as close
to the wheels as the timber will allow; ff are two copper chains attached by
one end to the lever bars, and by the other supporting two copper valves, which
660 GUNPOWDER.
are not seen in Fig. 1, being inside the tubs; but one of them is shown at g in
the section of a tub, Fig. 2. h h are two oval tubs capable of holding six
gallons of water, and having a circular hole at the bottom ; surrounding this
hole is a grooved block having a cylindrical channel all round it, into which the
bottom edges of the cylindrical valves fit, shown in section at Fig. 2. č i are
two small spring catches fastened to the two uprights. The lever bars are laid
on the top of these catches, so that when the ends of the levers rise, that part
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of the lever which is on the catch moves downwards, as shown by the dotted
lines, till it slips over the end of the catch, and thus the lever is prevented from
resuming its horizontal position till released from the catch. In order to fit
that part of the apparatus above described for action, bring the lever to a hori-
zontal position, place the valve g in the circular channel at the bottom of the
tub so as to cover the hole; fill the channel with mercury, and then fill the tub
with water; hence it is evident that the water is prevented by the mercury
from escaping out of the tub so long as the valve remains in its place. Now,
if an explosion happen in either of the mills, the blower e hanging over the
bedstone will be thrown up, and the lever will, in consequence, be brought into
the position indicated by the dotted line, and will be retained there by the
spring catches i i ; at the same time the valves g will be drawn up out of the

























HAIR. 661
mercury, and the water in both tubs will pour down on their respective bed-
stones, extinguishing in one the inflamed powder, and in the other preventing
it from taking fire. In a certain stage of the grinding the materials are apt to
clot and adhere to the runners; parts of the bedstones are thus left bare, and
the runner and bedstone coming in contact, an accidental spark may be
elicited, and an explosion ensue. To prevent this most usual cause of acci-
dents, Mr. Monk fixes to the axles of the wheel a scraper formed of a curved
piece of wood k shod with copper, which, being placed behind and almost
touching each of the runners, scrapes off the powder as it collects, and thus
keeps each of the bedstones always covered. l is the greater water-wheel,
which gives motion to the rest; m m are two vertical beveled wheels, fixed on
the axis of the great wheel; n n two horizontal bevel wheels working in m m,
and turning the vertical shafts, upon the upper part of which are also fixed two
horizontal wheels o 0, which drive the wheels p p. To the shafts of these latter
wheels are fixed the runners q q, which traverse on the bedstones u u : v v are
the curbs surrounding the bedstone to keep the powder from falling off. The
mill A presents a view, and the mill B a section of the bedstone and curb.
Fig. 2 shows the position of the apparatus after an explosion has taken place;
the valve being raised up out of the channel, and the water pouring down on
the bedstone.
GUNWALE, or GUNNEL, is the piece of timber in a ship which reaches
on either side from the half-deck to the forecastle, being the uppermost bend,
which finishes the upper works of the hull in that part.
GYPSUM. A substance which is very abundant in nature, and is now de-
nominated, according to the new chemical arrangement, the sulphate of lime.
It forms immense strata, composing entire mountains; it is found in almost
every soil, either in greater or less quantities; it is contained in the waters of
the ocean, and in almost all river and spring water. In these its presence is
the cause of the quality termed hardness, which may be known by the water
being incapable of forming a solution of soap, the sulphuric acid seizing on the
alkali of the soap, and the oil forming a compound with the lime. Sulphate of
lime is insipid, white, and soft to the touch; water will not hold a five-hun-
dredth part of it in solution. Exposed to heat it appears to effervesce, which
phenomenon is caused by the expulsion of water; it becomes opaque, and falls
into powder. This powder, when its water has been driven off by the appli-
cation of a red heat, absorbs water rapidly, so that if it be formed into a paste
with water, it dries in a few minutes. In this state it is called plaster of Paris,
and is employed for forming casts, and for a variety of purposes in the art of
statuary.
H.
HACKLE. An instrument or tool used in hackling or straightening the fibres
of flax. It consists of several rows of long sharp iron teeth, fixed in a piece
of wood, and placed with their points upwards before the workman, who strikes
the flax, which he holds in his hand, * the teeth of the hackle, drawing it
quickly through them. According to the quality of the flax, or the purpose
for which it is designed, the workmen use a hackle with finer, coarser, or wider
teeth; but generally using a coarse one first and a finer afterwards. See FLAx.
HAEMATITES. An ore of iron. *
HAIR. Slender filaments issuing out of the pores of the skins of animals,
and serving most of them as a covering. All hair appears round; but the
microscope shows them to be of various shapes, as square, triangular, hexan-
gular, &c. The human hair forms a considerable article of commerce, princi-
pally for the manufacture of perukes. The hair of northern countries is
preferred on account of its greater strength and length. Hair is sometimes
bleached on the grass like linen, after previous washing and steeping in a
bleaching liquid; it may then be dyed of any colour. When it does not curl
naturally, it is made to do so by first boiling it and then baking it in an oven.
4 P
662 HAND-MILLS.
M. Vanquelin, who investigated the chemical constituents of hair, found that
red hair differs from black only in containing a red oil instead of a blackish
green oil; and that white hair differs from both these only in the oil being
nearly colourless, and in containing phosphate of magnesia, which is not found
in them. Hair is usually distinguished into various kinds; the stiffest and
strongest, such as those on the back of swine, are called bristles. The soft and
pliable, like that on sheep, is called wool; and the finest of all is called down.
Hair is also woven into cloth (of which it forms only the weft) for covering the
seats of chairs and sofas, besides other purposes.
HAIR POWDER. The starch of wheat finely pulverized, and variously
scented.
HALBERT, or HALBERD. A kind of spear having a staff about six feet
long, much in use formerly, but now chiefly confined to the serjeants of
foot.
HAM. The leg or thigh of pork, dried, seasoned, and prepared to make it
keep, and give it an agreeable flavour. Westphalia hams, which are most
esteemed, are prepared by salting them with saltpetre, pressing them for eight
or ten days, then steeping them in juniper water, and drying them in the smoke
of juniper wood. The curing of hams in this country is, first, by common
salting, to extract the blood; the hams are then wiped dry, and afterwards
salted in a mixture of common salt, saltpetre, and brown sugar; in this pickle
they remain for about three weeks, and are afterwards dried in a chimney, or
on the great scale, in a stove constructed for the purpose.
HAMMER. A well-known instrument used by workmen, of which there
are numerous varieties, adapted to the peculiar work they are designed for.
The general form is that of an iron head, having a handle at right angles to it.
The class called rivetting hammers have the handle fixed to them by passing it
through a hole in the head, where it is made to fit or be wedged firmly; the face
is formed of steel, as well as the rivetting end (called the pans), which are welded
to the iron. These hammers are used by carpenters, smiths, engineers, and
numerous artisans, and vary in some peculiarities of form; and as respects
weight, from an ounce to many pounds, or that of a sledge-hammer. Of the
last mentioned there are various sorts and sizes; also of hand or up-hand
hammers, which are a medium size between the two before mentioned, and
are so called from the capacity of the wrkman to use them with one hand. A
variety of hammers having two claws, called claw hammers and Kent hammers,
are extensively used by carpenters and other trades, as the claw, together with its
handle, forms a powerful lever for drawing nails and other purposes requiring
great force. The late Mr. Walby, of Islington (who is succeeded by his son),
distinguished himself by the construction of a very ingenious apparatus, by which
he worked a hammer at the rate of 800 blows per minute, in the manufacture of
a very superior quality of bricklayers’ trowels. For the construction and mode
of working those prodigious hammers, called tilt-hammers, see the article IRoN.
HAMMOCK. A suspended bed, usually consisting of a piece of sacking
about three feet wide and six feet long, gathered or drawn together at the two
ends, and suspended from only one point at each end. They are chiefly used
on ship-board, and between decks; in warm countries they are likewise
employed for persons to sleep in the open air, by suspending them to posts
Or to trees.
HAND. A measure of four inches, or that of the clenched fist.
HANDCUFFS. Two circular pieces of iron, provided with hinge joints to
open and shut them by, and a lock to secure them when together; employed
to secure prisoners or malefactors. -
H AND-MILLS. This term does not properly apply to any specific kind of
mill, but to all that are worked by hand, such as those employed in the domestic
offices of grinding coffee, pepper, &c. There are, however, mills of a larger
description, which are also worked by hand for grinding malt, wheat, and other
substances; and in the houses for the reception and employment of the
poor, it is not uncommon to employ the united force of a great number of
persons in grinding corn and dressing the meal for the establishment; and the
HAND-MILLS. 663
Inode of applying their power is almost uniformly that of turning a winch or
crank, made of sufficient length for that purpose. The winch undoubtedly
possesses the advantages of great simplicity and convenience; and it has pro-
bably, on those accounts, been generally adopted. It has, however, been the
opinion of many eminent mechanics, that the most effective mode of employing
human force, is the action of rowing a boat. On this point the ingenious
Dr. Desaguliers observed, that more muscles are employed at once for over-
coming the resistance, than in any other position; and that the weight of his
body assists in the act of pulling backwards. The following mechanical
arrangement for carrying the principle into effect is given in Brockler's
Theatrum Machinarum. The ver-
tical shaft e carries a large N /
toothed wheel c ; the latter being
intended to operate partly as a U i
regulating fly. Upon the crank
a hangs one end of an iron b, the J’
other end of which hangs upon the
lever h l, the motion being per-
fectly free at both ends of the bar
l. One end of the lever h l hangs
upon the fixed hook f about which,
as a centre of motion, it turns;
then, while a man, by pulling at
the lever h l, moves the extremity
l from l to k, the bar b, acting upon 7
the crank a, gives to the wheel * * * - - - * * |
e half a rotation; and the momen- || `
tum it has acquired will carry them
on, the man at the lever suffering it to turn back from k to l, while the other
half of the rotation of the wheel is completed. In like manner another
sufficient pull at the lever h l gives another rotation to the wheel c, and so
on at pleasure. The wheel c turns by its teeth the trundle d, the spindle of
which carries the upper mill-stone. If the number of the teeth in the wheel
c be six times the number of the cogs in the trundle d, then the labourer, by
making ten pulls at the lever h l in a minute, will give sixty revolutions to the
upper mill-stone in the same space of time.
We have given insertion to this “rowing-mill,” as it is termed, on account
of the great praise bestowed upon it by succeeding eminent, writers; but we
cannot regard it as a very judicious mode of carrying the principle into effect,
for two reasons;–First, the large wheel making but ten revolutions per minute,
will not become a very efficient regulator of power; if fixed upon the first
motion, it must be made inconveniently large or weighty to collect the requisite
force to be useful. If a fly-wheel be used at all, it should be put on the axis
of the trundle d, where the velocity is six times greater ; the increased
momentum it would here acquire, would far more than compensate for the
small loss of effect by its removal farther from the motive force. But we doubt
much the use of a fly-wheel at all in the present case, because a heavy mill-
stone is put into operation; and that is, in effect, a far more efficacious fly-
wheel than the above described. Second, because we think the inventor has
imitated the defects as well as the advantages of the rowing action. . In this
mill the workman is supposed to pull the lever h 1 through the arc of a circle
l k; and this indirect action, it will be noticed, is performed in a horizontal
plane, by which a contortion of the man's body results that must be unfavour:
able to his health, and the most efficient exercise of his strength. To avoid
these defects in the rowing-mill, we propose the following simplified, and, we
trust, improved arrangement. a represents a seat for one or two men; b a
board to press their feet against in pulling back by the cross handle c, which is
connected to a rod d that slides straight through brasses fixed in a standard e :
at f is a hinge joint, which permits the connecting rod g to vibrate with the
revolution of the crank h, whose axis actuates the wheel i, the pinion or

664 HARMONICA.
trundlej, on the axis k of which, is fixed the runner-stone l, serving also the
office of a fly-wheel. In applying the labour of more men to an apparatus of
this kind, there would be some advantage in placing them opposite to each
other so that a pull should be made each way. For this purpose the rod dd
might be lengthened, another seat be placed on the other side of the standard e,
and another cross handle between d and f; the men sitting here on each side
of the rod d. -
Having now explained what is deemed the most advantageous application of
manual labour to mills, and the undefined nature of the term which heads this
article, we refer the reader for more information on the subject, and that of mills
generally, to the article MILL,
HANDSPIKE. A name given to a simple lever consisting of a bar of wood
or iron, chiefly used on board ship for heaving round the windlass.
HAR BOUR. A place where ships may lie at anchor, secure from storms.
The principal qualities of a good harbour are, sufficient depth of water to float
the largest ships, and sufficient breadth and depth for them to enter with facility,
and without danger of foundering. The ground should be firm, and free from
rocks. It is desirable that they be surrounded by lofty hills or mountains, to
screen them from high winds, and the better if so far inland as to derive there-
from increased security against being bombarded by an enemy at sea. They
should also be provided with a good light-house to direct ships at night, and
with numerous buoys, posts, moorings, &c. Harbours are sometimes formed
artificially, either wholly or partially, by the building of moles, breakwaters,
piers, and sometimes by large floating masses of timber, which rise and fall
with the tide. See the articles Buoy, BREAKwATER, and CAIsson.
HARDNESS. The resistance opposed by a body to the separation of its par-
ticles. This property depends on the force of cohesion, or on that which
chemists call affinity, joined to the arrangement of the particles to their figure,
and other circumstances. The differences between hard bodies, such as are
soft, and such as are elastic, have been thus defined. The soft body yields to
pressure without spontaneously returning to its previous form on taking off the
pressure; the elastic body returns to its original form upon removing the force
applied; while that which is strictly hard breaks asunder when overcome by the
force brought against it. It is, however, justly doubted whether there is any
body in nature that is perfectly hard, perfectly soft, or perfectly elastic ; for all
bodies seem to possess these three qualities, though in proportions indefinitely
War IOU.S.
HARDENING and CASE-HARDENING. See IRoN and STEEL.
HARMONICA. The name given to a musical instrument invented by

HARPOON. 665.
Dr. Franklin, in which the tones are produced by friction against the edges of a
series of glasses. The glasses are blown as near as possible into the form of hemi-
spheres, having each an open neck or socket in the middle. The thickness of
the glass near the brim is about one-tenth of an inch, but thicker as it comes
nearer the neck, which, in the largest glasses, is about an inch deep, and an
inch and a half wide within ; these dimensions lessening as the glasses them-
selves diminish in size, except that the neck of the smallest ought not to be
shorter than half an inch. The largest glass is nine inches in diameter, and
the smallest three inches. Between these there are twenty-three different
sizes, differing from each other a quarter of an inch in diameter. The glasses
being chosen, and every one marked with a diamond the note for which it is
intended, they are to be tuned by diminishing the thickness of those that are
too sharp. This is done by grinding them round from the neck towards the
brim, the breadth of one or two inches, as may be required, often trying the
glass by a well-tuned piano-forte or harpsichord. The largest glass in the
instrument is C, a little below the reach of a common voice, and the highest G,
including three complete octaves; and they are distinguished by painting the
apparent parts of the glasses within side, every semitone white, and the other
notes of the octave with the seven prismatic colours; so that glasses of the
same colour (the white excepted) are always octaves to each other. The glasses
being tuned, they are to be fixed on a round spindle of hard iron, an inch in
diameter at the thickest end, and tapering to a quarter of an inch at the smallest.
For this purpose the neck of each glass is fitted with a cork, projecting a little
without the neck; these corks are perforated with holes of different diameters,
according to the dimensions of the spindle in that part of it where they are to be
fixed. The glasses are all placed one within another, the largest on the biggest
end of the spindle, with the neck outwards; the next in size is put into the
other, leaving about an inch of its brim above the brin of the first; and the
others are put on in the same order. From these exposed parts of each glass
the tone is drawn by laying a finger upon one of them as the spindle and glasses
turn round. The spindle thus prepared is fixed horizontally in the middle of a
box, and made to turn on brass gudgeons at each end. A square shank comes
from its thickest end through the box, on which shank a fly-wheel, to equalize
the motion, is fixed. This wheel is made of mahogany, eighteen inches in
diameter, and pretty thick, to conceal near its circumference about 25lbs. of
lead. An ivory pin is fixed to the face of this about four inches from the axis,
and over the neck of this pin is put the loop of a string from a treadle, by which
the machine is put in motion. The whole is put in a neat case, and stands on
a frame with four legs. The case is three feet long; eleven inches wide at the
largest end, and five at the smallest; it is made with a lid, which opens at the
middle of its height, and turns up by back hinges: the instrument is played
upon by sitting before the middle of the set of glasses, turning them with the
foot, and wetting them now and then with a sponge and clean water. The fin-
gers should be first a little soaked in water, and quite free from greasiness; a
little fine chalk is sometimes useful to make them catch the glass, and bring out
the tone more readily. Both hands are used, by which means different parts
are played together. “The advantages of this instrument are,” says Dr.
Franklin, “that its tones are incomparably sweet beyond those of any other;
that they may be swelled and softened at pleasure by stronger or weaker pres-
sures of the finger, and continued to any length, and that the instrument being
once well tuned, never again wants tuning.”
HARNESS. The furniture and equipments of horses, to adapt them for
drawing carriages, and for being driven, guided, and controlled. The con-
stituent parts of harness are noticed under their separate heads. See Collar,
SADDLE, CARRIAGE, &c.
HARP. A stringed instrument, consisting of a triangular frame, the chords of
which are distended in a parallel direction from the upper parts, to one of its sides.
HARPOON, or HARPING-IRon. A javelin used to pierce whales, in the
Greenland and South Sea fisheries. It has a broad, flat, triangular, barbed
head, well sharpened, to penetrate easily, and a shank about two feet long, to
.e.
666 HARROW.
the extremity of which is fastened a long line, which lies carefully coiled in the
boat, in such a manner that it may run out easily, and without entangling.
As soon as the boat has come within a competent distance of the whale, the
harpooner launches his instrument, and the fish, immediately he is wounded,
descends with amazing rapidity, carrying the harpoon along with him, and a
considerable length of the line, which is purposely let down to give him room
to dive. Being soon exhausted with the fatigue and loss of blood, he re-ascends,
in order to breathe, where he presently expires, and floats upon the surface of
the water; when they approach the carcase by drawing in the whale line.
This line is from sixty to seventy fathoms long, and made of the finest and
softest hemp, that it may slip easily. To prevent the boat taking fire by the
friction of the line against it, it is constantly watered as it passes out. The
harpoon is also employed to catch sturgeons, and other large fish. About a
century ago, guns were tried for discharging harpoons, on the presumption that
they could strike the whales at greater distances than by hand. They were
tried for several seasons, but their employment has been ever since abandoned. .
HARPSICHORD. A stringed instrument contained in a large case of
wood, having a double or treble row of distended strings, of brass and steel
wires, supported by bridges. It is played upon similarly to the piano-forte, but
instead of hammers covered with leather, the tone is produced by little upright
pieces of wood, called jacks, furnished with pieces of crow-quill, which strike
the wires. The piano-forte has now almost wholly superseded the harpsichord.
HARROW. An agricultural implement, used for raking and levelling the
earth. There are two principal distinctions; namely, the common, and the
jointed chain harrow. The common harrow is usually made by framing toge-
ther a number of stout parallel bars, by means of the like number of similar
bars, equidistant, and crossing the others at right angles, thus leaving
uniform square spaces between them. To strengthen this frame, a bar is
fixed diagonally across them. The spikes or tangs, which are made from
four to twelve inches in length, (according to the nature of the soil, or work
to be performed,) are fixed to this frame either by nuts and screws, or by rivet-
ting them down upon iron washers, after passing them through the wood. The
frame of course lies flatways upon the ground, with the tangs to the ground,
and it is drawn across the field by cattle yoked to a chain fastened to one corner
of the harrow. The chain or screw harrow is made to divide diagonally into
two parts, thus forming, as it were, two triangular harrows, which are hooked
and chained together. This contrivance adapts itself better to the ridges and other
inequalities of the ground. Sometimes, in lieu of this, two common harrows
are chained together, and applied to effect the same object.
HARTSHORN SHAVINGS. These shavings, although originally taken from
the horns of stags, or harts, which are a species of bone, are now obtained
chiefly by shaving down with a plane the bones of calves. They afford a
nutritious and speedily formed jelly.
HARTSHORN, (SPIRIT of,) is now usually obtained by the distillation of
bones, hoofs, horns, and in general the refuse of slaughter-houses. An iron
still or retort is generally used with a pipe leading from it into a worm con-
denser. The retort is filled with bones roughly broken, or other materials, and
a strong heat applied. Water, and a tar-like oil, accompanied with a foetid inflam-
mable gas, result; carbonic acid also comes over, but this is mostly taken up
by the ammonia, which is formed at the same time, and received in the state of
carbonate of ammonia. When the different substances have been condensed in
the worm, they should pass into a receiver, which has no communication with
the open atmosphere, (on account of the overpowering nuisance of its odour,)
but which should have a pipe inserted into the upper part of it, and connected
with the ash-pit of the still. The inflammable gas and the smell are conveyed
to the fire, where the former ignites; but care must be taken to avoid any
explosion, for when the evolution of the inflammable gas becomes slow,
or ceases ſentirely, the common air passes along the pipe into the close
receiver, which is filled with the same inflammable gas; and, under these cir-
cumstances, an explosion will take place, which will not only burst the receiver,
HAT'MAKING. 667
but do other injury. This evil, Mr. Gray observes, may be avoided by placing
a valve in the pipe opening outwards, to allow the passage of the gas; and
another valve into the receiver, opening inwards; by this means the flaming gas
will be stopped in its passage to the receiver; as the valve into the receiver open-
ing, will admit the common air to fill up the vacuum. Thus, by means of this
apparatus, if it be well constructed, and proper luting be employed, the distilla-
tion of hartshorn may be carried on almost without any smell, although the
odour of animal oil is so remarkably offensive. The first product consists of
water, animal tar, and volatile salt. A great part of the tarry oil may be sepa-
rated mechanically; the rest, in a great measure, by a second distillation with
a gentle heat. The liquid which comes over consists of a solution of sesqui-car-
bonate of ammonia, with a fetid animal oil, which gives it a peculiar odour.
This liquid is still sold in the shops under the name of spirit of hartshorn, as
the alkaline liquor obtained from that substance was at one time thought to
possess certain medical virtues, not to be found in the alkaline liquor obtained
from other animal matters.
HATS. A well-known covering for the head, and distinguished from a cap
or bonnet by a brim. They are made by various methods, according to the
nature of the substance of which they are composed; but by far the greatest
number are formed of the fur of different animals, by a process called felting:
this manufacture has of late years become of considerable commercial impor-
tance, and numerous improvements have been introduced into it. The materials
for making hats are chiefly rabbits’ fur, cut off from the skin, together with
wool and beaver, to which may also be added mole fur, and kid hair. These
are mixed in various proportions, and of different qualities, according to the
value of the hats intended to be made; but the beaver is now wholly used for
facing the finer hats, and not for the main body or stuff. The first process in
the manufacture of hats is termed bowing, which has for its object to separate
the fibres, and break up any clots, so as to form the whole into a kind of light
down: it is performed as follows—the workman is provided with a pole of ash,
or white deal, about seven feet long, having a bridge at each end, over which is
stretched a catgut about , of an inch thick; and a portion of the material being
laid upon a hurdle of wire, he holding the bow horizontally in his left hand,
nearly in contact with the material, gives the string a pluck with a wooden pin,
held in his right hand. The string, in its return, strikes the fur, and causes it to
spring up in the air, and fall in a light open form, at a little distance from the
mass. By repeated strokes, the whole is subjected to the bow; and having thus
fallen together in all directions, it forms a thin mass or substance for the felt.
The quantity thus treated at once is called a batt, and never exceeds half the
quantity required to make one hat.
When the batt is sufficiently bowed, it is ready for hardening, which is the
term for the commencement of the felting. The prepared material being evenly
disposed on the hurdle, is covered with a linen cloth, and pressed backwards and
forwards in its various parts by the hands of the workman. The pressure is gentle,
and the hands are very slightly moved backwards and forwards, at the same
time, through a space of perhaps a quarter of an inch, to favour the hardening
entangling of the fibres. In a very short time, the stuff acquires sufficient
firmness to bear carefully handling. The cloth is then taken off, and a sheet
of paper, with its corners doubled in, so as to give it a triangular outline, is laid
upon the batt, which last is folded over the paper as it lies, and its edges,
meeting one over the other, form a conical cap. The joining is soon made good,
by pressure with the hands on the cloth. Another batt ready hardened is in
the next place laid on the hurdle, and the cap here mentioned placed upon it
with the joining downwards. This last batt being also folded up, will have its
place of junction diametrically opposite that of the inner felt, which it must
therefore greatly help to strengthen. The principal part of the intended hat is
thus put together, and now requires to be worked with the hands a considerable
time upon the hurdle, the cloth being also occasionally sprinkled with clear water.
During the whole of this operation, which is called basoning, the felt becomes
firmer and firmer, and contracts in its dimensions. The use of the paper is to
1668 HAT-MAKING. w
prevent the sides from felting together. The basoning is followed by a still
more effectual continuation of felting, called working, which consists in plunging
them into a cauldron containing water slightly acidulated with sulphuric acid, and
then working them upon some planks forming the frustrum of a cone, meeting
in the cauldron at the middle. The imperfections of the felting now appear;
and the workman picks out the knots and other hard substances with a bodkin,
and adds more fur upon all such parts as require strengthening. . This added
fur is patted down with a wet brush, and soon incorporates with the rest.
Towards the close of this working, the beaver for the nap is laid on. By these
means, the substance of the hat is formed into a felt of close texture, pliable, and
capable of extension (although with difficulty), in every direction, but the figure
is still conical; the next thing to be done, therefore, is to give it the required shape.
For this purpose the workman turns up the edge or brim to the depth of about
an inch and a half, and then returns the point back again through the centre
or axis of the cap, so far as not to take out this fold, but to produce another
inner fold of the same depth. The point being returned again produces a
third fold, and thus the workman proceeds until the whole has acquired the
appearance of a flat circular piece, consisting of a number of concentric folds
or undulations with the point in the centre : this is laid upon the plank, where
the workman, keeping the piece wet with the liquor, pulls out the point with
his fingers, and presses it down with his hands, at the same time turning it
round on its centre in contact with the plank until he has by this means rubbed
out a flat portion equal to the intended crown of the hat. In the next place he
takes a block, to the crown of which he applies the flat central portion of the
felt, and by forcing a string down the sides of the block, causes the next part
to assume the figure of the crown, which he continues to wet and work until it has
. disposed itself around the block. The brim now appears like a puckered
or flounced appendage round the edge of the crown; but the block being set upright
on the plank, the requisite figure is soon given by working, rubbing, and extending
this part. Water only is used in this operation of blocking or fashioning; at the
conclusion of which it is pressed out by the blunt edge of a copper implement
called a stamper. Previous to the dying, the nap of the hat is raised or
loosened out with a wire-brush or carding instrument. The fibres are too rotten
after the dying to bear this operation. The dying materials are logwood, a
little oak bark, and a mixture of the sulphate of iron and of copper, known in
the marts by the common name of green copperas and blue vitriol. The hats
are boiled with the logwood, and afterwards immersed in the same solution. The
dyed hats are, in the next place, taken to the stiffening shop. One workman,
assisted by a boy, does this part of the business; he has two vessels or boilers,
one containing the grounds of strong beer, and the other containing melted
glue, a little thinner than what is used by carpenters. The beer grounds are
applied in the inside of the crown to prevent the glue from coming through to
the face, and also to give the requisite firmness, at a less expense than could
be produced by glue alone. The glue stiffening is therefore applied after the
beer grounds are dried, and then only upon the lower face of the brim and the
inside of the crown. The dry hat, after this operation, is always rigid, and its
figure irregular. The last dressing is given by application of moisture and
heat, and the use of the brush, and a hot iron, as before mentioned, somewhat
in the shape of that used by tailors, but shorter and broader on the face. The
hat being softened by exposure to steam, is drawn upon a block, to which it is
securely applied by the former method of forcing a string down from the
crown to the commencement of the brim. The judgment of the workman is
employed in moistening, brushing, and ironing the hat, in order to give and
preserve the proper figure. Before the hat is quite finished, the brims are cut
by a knife attached to a radius rod so as to describe a circle; the cut is not
carried entirely through, so that one of the last operations consists in tearing off
the redundant part, which, by that means, leaves an edging of beaver round
the external face of the brim. When the hat is thus finished, the crown is tied
up in gauze paper, which is neatly ironed down, and it is then ready for the
subsequent operations of lining, &c. for sale.
HAT-MAKING. 669
in that ably conducted work, Nicholson's Journal, Vol. IV. 4to, are several
suggestions for effecting many of the foregoing operations by machinery.
Amongst other subjects proposed for inquiry are the following:—whether
carding, which is rapidly and mechanically done, be inferior to bowing; whether
a succession of batts or carding might be thrown on a fluted cone, which rapidly
revolving in contact with three or more cylinders, might perform the hardening
and even the working with much more precision and speed than they are now
done by hand; and whether blocking or shaping be not a process extremely
well calculated for the operation of one or more machines. These ingenious
suggestions have recently been in some measure acted upon.
In 1826 Mr. G. Borradaile obtained a patent for an apparatus for the making
or setting up of hat bodies, as it is termed, in which several cones or frustrums
of cones are made to revolve upon their axes; and the frames in which these
Pº T
Fig. 1.
| l—!
Ti
DE-l —-mº.
*º-
cones act being made to vibrate horizontally on a fixed pivot and swivel, the
filaments of wool are caused to traverse each other diagonally, as they are
wound upon a double cone, and by that means to produce a matted substance,
which is afterwards to be wetted, shrunk, and felted together in the usual
manner. The bodies of two hats, each of a conical figure, are thus made over
the surface of a double cone, which are separated by cutting them along their
middle or base line, and slipping them . at the end. a a in the diagram,
represents this double conical block, and b b two conical rollers, of which there


- 4 Q
670 HATCHING OF FISH
are two more on the opposite side of the machine, not seen in this view. The
axes of these four rollers are placed in such an inclined position as to admit the
double come a a to bear equally upon them. The two front cones b b have
fixed upon their bases two bevelled toothed wheels, which gear into one another
as shown ; and rotary motion is given to both by the teeth of one of them
taking into a bevelled tooth and pinion that revolves upon a vertical spindle, to
which motion is communicated by a band and rigger. The large double cone
a a, therefore, is made to revolve slowly by the friction of its surface against the
four comical rollers underneath. The sliver of wool being conducted from the
doffer of a carding engine, placed behind the machine, to the upper side of
the double cone a a, and the cones b b being made to revolve as before
described, causes the sliver of wool to be wound round the periphery of a a in
an uniform layer. In order to give a diagonal crossing to the filaments, as
they are wound upon the double cone, the machine is made to turn partly
ound horizontally upon the pivot k in front, and upon a swivel joint l at top,
to which the back part of the machine is attached by a bent rod m m, the form
of which bent rod is explained by the separate Fig. 2. The gearing, by which
the vibrating motion of the machine is effected, is not brought into view in the
figure, as it could not be distinctly exhibited; but it may be easily compre-
hended that a rotary crank and lever will effect this movement. The plan
above described, it will be seen, very closely resembles that suggested by
Mr. Nicholson for preparing the bodies of hats; that which we are about to
describe as nearly resembles his plan for finishing them.
Mr. Ollerenshaw, of Manchester, about the year 1824, took out a patent for
a machine for assisting in the dressing and finishing of beaver or felt hats, by
which the ordinary labour in those operations is materially reduced, and the
work is completed in much less time. It is constructed on the principle of the
lathe, and the apparatus consists of three principal parts or lathes, which are
all fixed in one strong frame, and motion is given to them by means of a band
passing from any first mover, (as a steam-engine, water-wheel, &c. &c.) The
first of these lathes is constructed the same as the common wood-turner's lathe,
and is used for the purpose of ironing or dressing the sides of the crown; the
block upon which the hat is fixed is made to fit on the chuck of the lathe, and
as the hat revolves, the hot iron is applied to the surface by the workman,
which quickly smooths the hat, giving it the usual glossy appearance; the
velvet cushion, and the various brushes hatters use, are likewise applied, as
may be required, while it is thus revolving, till that part of the hat is finished,
when it is removed and placed upon the block of the next lathe. This second
lathe is constructed with a vertical shaft, so as to produce a horizontal rotary
motion to the hat, which is better suited for operating upon the flat part of
the crown, and the upper side of the brim, than a vertical motion. The hat
having undergone the usual manipulations in the second lathe, is removed to
the third, where it is introduced, in an inverted position, into a frame made to
receive it, which turns round very slowly in a horizontal direction (the axis
being vertical); here the workmen smooth the under side of the brim, by
drawing the iron across it from the centre outwards. The hat next undergoes
the usual examinations, and pickings-out of the extraneous and coarse hairs;
after this, it is again subjected to the former operations of ironing and brushing,
which finishes it. - 3.
HATCH, and HATCHWAY. Hatchway is the square or oblong opening
through a ship's deck; and the cover to it is the hatch, which is sometimes pro-
vided with a grating, to admit light and air beneath.
HATCHET. A small axe used with only one hand. See Axe.
HATCHING. The production of chickens, or other animals, alive, from
eggs, whether by incubation of the parent, or by artificial heat. Under the
article Eggs, we have described the mode of hatching chickens by the heat of
ovens. In the next article we shall notice the important art of hatching fish,
which is practised with much success in China.
HATCHING OF FISH. The Chinese hatch the spawn of fish, by collect-
ing it on the margin and surface of the water, and then filling the shell of a
HELIOMETER. 671
newly laid egg with the gelatinous matter that contains the spawn. The hole
in the egg is waxed over, and it is put under a sitting hen. At the expiration
of a certain number of days, they break the shell in water warmed by the sun.
The young fry are presently hatched, and are kept in pure fresh water till they
are large enough to be thrown into the pond with the old fish. The sale of
spawn for this purpose forms an important article of trade in China.
HATCHMENT. The coat of arms of a dead person, usually placed in the
front of the house.
HAUTBOY. A musical instrument provided with keys like a flute, but
blown by a reed at one end, and spreading out conically towards the other end.
HAY. Grass dried in the sunshine. The risk of this operation being suc-
cessfully completed, owing to unfavourable changes in the weather, is well
known; and the loss to the farmer in consequence of long continued rains and
floods, after the grass is cut, is sometimes very severe. It has occurred to us
that a remedy for so serious an evil might be found, in providing some
simple temporary erections in the hay field, the cost of which would be far less
than the value of the crop saved. Four posts, or hop poles, might be fixed in
the ground, so as to form a quadrangle, with one in the middle, of greater
height, as a central support, and to form the apex of a conical top or roof. At
about a foot from the ground, some very coarse netting might be stretched
horizontally from pole to pole, and thereto tied; a quantity of the green hay
might be thrown lightly upon this. Then, above this layer, a second floor of
net work might be laid, with a sufficient space underneath for the free passage
of the air, and upon it a second stratum of the wet hay may be thrown; proceeding
in this manner, tier above tier, as high as may be convenient; which, by the
assistance of a waggon as a stage, might easily be raised to twelve feet, and be
covered either by a tarpaulin, or a conical top of hay. In erections of this
kind, the hay would thoroughly dry, and the materials of which they are formed
would last many years, might easily be stowed away, and be useful for other pur-
poses. The coarse netting in which woollen rags are packed, made of the tarred
strands of old cables, would be very cheap, strong, and durable. The Tyrolese
have a method of preserving their hay crops which seems to deserve imitation
in this country, as it may be perhaps more generally and easily practised. It
is thus described by Mr. Brockedon, in a letter to the Society of Arts, &c.
“I have observed, in the course of my journeys in the Alpine districts, that
the hay is preserved in the meadows and on slopes, in situations where the
cocks are exposed to the action of torrents, by being cocked upon stakes
having two or three transverse pieces of wood fixed in them. The stake is light,
about five or six inches in circumference, and about four or five feet long.
These are kept by the farmers in large quantities, and stowed away compactly
during winter, under the overhanging roofs of their dwellings. When used,
they are driven upright into the ground at convenient distances, and the grass
when cut is thrown upon them: it is supported upon the cross pieces or arms
of the hay-stake, on which a large cock may be formed; the lower part is free
from the ground, while the outside, raked smooth, carries off the rain; in this
manner it is often left for weeks, if necessary; the air freely entering and
circulating, dries the hay, and frequently it is never spread, except during part
of the favourable day in which it is housed.
HEARTH. The pavement or surface on or over which fuel is burned in
apartments. But the term hearth, in naval affairs, implies, the grate and appa-
ratus employed on board ship for preparing the food or messes for the ship's
company. It is fixed upon deck, in a small covered building, fitted up with a
variety of conveniences for the cook and his operations. The modern apparatus
usually comprises a steam boiler, coppers, ovens, hot closets, in addition to a
large open fire.
HEAT. See CALoric, also CHEMISTRY.
HELIOMETER, or ASTROMETER, is an instrument invented by Bougeur,
for measuring with exactness the diameter of the sun, moon, and planets.
This instrument is a telescope, having two object-glasses of equal focal distance,
placed side by side, so that the same glass serves for both. The tube of this
672 HELM.
instrument is of a conical form, larger at the upper end (which receives the
two object-glasses) than at the lower, (which is furnished with an eye-glass and
micrometer.) Hence, two distinct images are formed in the focus of the eye-
glass, the distance of which depending upon that of the two object-glasses from
one another, may be measured with the greatest accuracy.
HELIOSCOPE. A telescope fitted for viewing the sun, without dazzling
the eyes, by being provided with object and eye-glasses, that are coloured red
or green. Huygens used only a plain glass blacked over the flame of a candle,
which he placed between the eye and the eye-glass.
HELIOTROPE is a sub-species of rhomboidal quartz. It is regarded as a
precious stone; the colour green, of various shades, and streaked with red
veins. . The blood and scarlet-red, and the yellow dots and spots are owing to
disseminated jasper.
HELM. In naval architecture, the apparatus for steering or guiding the
motion of a ship. The helm is usually composed of three parts—the rudder,
the tiller, and the wheel, except in small vessels, where the wheel is unneces-
sary. The rudder is a long and flat piece of timber, or assemblage of timbers,
suspended along the hind part of a ship's stern-post, and turning upon hinges.
The tiller is a long beam or lever fitted into the head of the rudder within the
vessel, by means of which the rudder is turned to the right or left, as occasion
requires. In order that the steersman may remain stationary, so as to see the
compass placed in the binnacle, ropes, called tiller ropes, are attached to the
end of the tiller, and, passing through leading blocks in the vessel's side, are
pulled by the steersman; where an increased power is required, small tackles
are employed: but in large vessels, the tiller ropes are wound upon a barrel or
cylinder, which is turned by means of a wheel set upon the same axis, and fur-
nished with six or eight projecting spokes. The effect of the rudder in changing
the direction of a ship's head, according as it is turned to either side, arises
from the current produced by the vessel's passage through the water striking

HELLEBORE. 673
more forcibly upon the side which is turned against the current, than upon
the opposite side which is turned from it; and, as the rudder placed at the
extreme end of a ship may be considered as appended to a lever, the fulcrum
of which is somewhere about the centre of the vessel, the pressure thus
exerted against it naturally causes the ship to turn upon the centre of gyra-
tion, the effect being proportioned to the velocity of the current, and to the
angle at which the rudder stands opposed to it. Ships which have what is
called a full buttock, that is, carry their breadth very far aft, are found not to
answer the helm readily, owing to the water not coming easily to the rudder.
To remedy this defect, a false stern-post is sometimes bolted on, and the breadth
of the rudder increased. Mr. E. Carey, surveyor of shipping at Bristol, pro-
poses, as a more effectual remedy for vessels having the above defect, to bolt on
to the keel a piece one foot six inches abaft, running its breadth two-thirds for-
wards, then tapered off to nothing as far as the gripe, and to bolt another piece
of equal breadth on to the bottom of the rudder (as shown in the drawings,
Fig. I and 2, on the preceding page,) which will make the ship hold a better
wind, and answer her helm quickly, and steer perfectly easy. By reference to
Fig. 3, it will be seen that the effect of the water upon the additional piece will
be fully equal to that upon the whole of the rudder before it was put on ; for
the water rushing along the flat bottom of the vessel, and along the side of the
keel, without obstruction, strikes upon the new piece with great force, and at an
advantageous angle, and necessarily makes the vessel answer her helm quickly.
Ships of war, and other large vessels, if they happen to strike the ground when
riding heavily at anchor, or by tailing on a sand bank, are very liable to injure
the rudder by tearing it away from its fas- º
tenings. To prevent this, Mr. Hillman, yºv-->~~~~~
of Deptford, proposes that the lower part
of the rudder should be made capable of
sliding up into a cavity prepared to receive
it, and of descending by its gravity into
its original position, as soon as the vessel
gets clear again. The changes in the
construction of the rudder which Mr. Hill-
man's plan would occasion, are represented
in the subjoined figure, which is a broad-
side view of it. a the stern post; b part
of the keel; c the rudder, the bottom of
which is cut away to the dotted lines d d,
ff is a metal segment, turning upon the
ping, and sliding within the case e e : this
segment is made hollow from the top on
two compartments, as shown by the dotted
lines h h; it falls by its own weight into
the position shown in the figure, and is
prevented from coming further by a projection from its top, lodging on a step
at i, within the case e e. The cavity.jj, from the bottom of the case e e to the
dotted lines d d, is made large enough to receive the whole of the segment ff.
If, therefore, the vessel should touch the ground, so as to endanger the rudder,
this segment would slide into the recess, and thereby avoid the blow, and would
fall out again to restore the length of the rudder when clear of the ground.
The Society of Arts plesented to Mr. Hillman their large silver medal for this
invention.
HELIX, in Geometry, is a term generally used synonymously with spiral;
but some authors make a distinction between the helix and the spiral. Daviler
says, that a staircase is a helix or helical when the steps wind round a cylin-
drical newel; but that a spiral winds round a cone, and is continually approach-
ing nearer and nearer to its axis.
HELLEBORE. The root of a plant formerly used in medicine, but
now nearly discarded from practice, on account of the violence of its
operation.

6'74 HINGES.
HELMET. A defensive armour for the head, composed usually of the skins.
of animals and of metals. -
HEMATIN. The colouring principle of logwood, which is obtained by
digesting alcohol for a day on the aqueous extract of logwood; then filtering
the solution, evaporating partially, and leaving the liquid to rest, hematin will be
deposited in small crystals, which, after washing with alcohol, are brilliant, and
of a whitish red colour, having a bitter, acrid and slightly astringent, taste.
Hematin forms an orange-red solution with boiling water, becoming yellow as
it cools, but recovering with increase of heat its former hue. Excess of alkali
converts it first to a purple, then to violet, and lastly to brown. Metallic oxides
combine with hematin, forming blue-coloured compounds. Gelatin throws down
reddish floculi; peroxide of tin and acid redden it.
HEMISPHERE. One-half of a globe or sphere, formed by a plane passing
through its centre.
HENBANE. A poisonous narcotic plant, common in our ditches and road-
side. It is sometimes used in medicine. See HyoscIAMA.
HENNA. A plant growing in Africa and many parts of the East; the
colouring matter being much in request for dyeing the finger nails of the inha-
bitants of the East, and the mains, tails, and hoofs of their horses. The
colouring matter of the plant is very abundant, and might be advantageously
used for dyeing woollens yellow and brown, of various shades, by combining it
with alum and sulphate of iron. The leaves are dried, powdered, and made
into a paste for the above-mentioned purposes. The powdered leaves form a
large article of export to Persia and the Turkish possessions.
HEPATIC AIR. Sulphuretted hydrogen gas.
HERMETICAL SEALING, is used to denote the perfect closing of vessels
so as to prevent the ingress or egress of the most subtle fluids or bodies. In
stopping glass vessels, for chemical operations, it is usual to heat the neck until
it is quite soft, and then twisting it by a pair of pincers; sometimes a plug
well luted serves the purpose effectually.
HIDES. The skins of beasts; the word being, however, distinctively applied
to the skins of oxen, cows, horses, and other large thick-skinned animals. Raw
or green hides are those which have not undergone any preparation. Seasoned
hides are those which have been salted with alum and saltpetre, to preserve
them until they undergo the process of tanning and currying. See LEATHER.
HIGH-WATER. That state of the tides when they have flowed to the
greatest height, in which state they remain nearly stationary for about
fifteen or twenty minutes, when the water begins to ebb. The time of
high-water is always nearly the same in the same place at the full of the moon;
and at all other times the time of high-water depends upon the age of the
moon; the rule for finding which, the age of the moon being given, is as fol-
lows: viz. Add four-fifths of the moon's age, as so many hours, to the time of
high-water at the full of the moon, and the sum is the time of high water
answering to that day, nearly.
HINGES. The joints on which doors, lids, gates, shutters, and an infinite
number of articles are made to swing, fold, open, or shut up, Independently
of a great variety of kinds and sizes kept ready made by ironmongers, there is
a constant demand for others of novel forms or properties to adapt them to
particular objects. The chief varieties are the following:—cross-garnets, made
in the form of the letter T, for gates and out-house doors, from 6 inches to 36
inches long; and a nearly similar kind made with long straps and hooks to fix
in the stiles, to enable the gates or doors to be lifted off their hinges at plea-
sure. Those used in common for the doors of apartments are termed butts, of
which there are many varieties. Those used for shutters are called backflaps :
similar hinges are used for the joints of bedsteads, and very nearly the same
kind for Pembroke and other tables; another sort, called H and HL hinges, from
their resemblance to those letters, are extensively employed for common pur-
poses. There are also many other sorts, distinguished by appellations that
designate their uses, and are too numerous to mention. All the various sorts
are, or may be made in the different metals, and most of them are to be found
HINGES. 675.
ready manufactured in wrought-iron, cast-iron, and brass, and differently
finished. The chief manufactories are at Birmingham, Wolverhampton,
Tipton, and several parts of Staffordshire. The best of the wrought-iron kind
are made in Lancashire, and the heavier sort at Newcastle. We have several
excellent hinge manufacturers in London; amongst whom should be particu-
larly noticed §. Collinge and Son, and Mr. Redmund, on account of their
admirable improvements, which have been the subject of patent rights. Instead
of the ordinary plan, of a cylindrical joint working round a fixed central pin,
Messrs. Collinge form the end, as it were, of the pin, into a sphere, over which
a hollow spherical cap fixed to the other limb of the hinge is made to fit accu-
rately; this is provided with a cavity for the reception of oil, having a small
perforation to conduct it between the two spherical surfaces, which work with
great truth and freedom. The principle of the invention is unquestionably
good, and by paying great attention to the manufacture of the article, the
inventors have succeeded in obtaining for them a high reputation; they are, in
consequence, extensively adopted, especially in turnpike-gates, where their
neatness, efficiency, and durability, have established them almost as an indis-
pensable appendage.
Mr. Redmund, of the City Road, has likewise, with great skill and assiduity,
bent his attention to the improvement of hinges, in giving them new features
and properties, and in finishing them in a style of unusual excellence. We
have been informed by an architect of great eminence, that Mr. Redmund pos-
sesses a rare degree of ingenuity in adapting hinges to apparently impracticable
situations, in giving them an ornamental or a symmetrical appearance where they
would in general be deemed a disfigurement, and in rendering them invisible
when the style of architecture does not admit of any variations or additions;
and that it was on this account that he was employed in rehanging the doors in
Windsor Castle, in the recent splendid improvements made in that palace by
the late king. This excellent mechanic was educated a carpenter, and being
now an engineer and iron founder of some repute, he unites, as it were, within
himself, all the resources of his art. Our assigned limits will not permit us to
give a detailed description of the variously formed hinges made by this manu-
facturer, but we will just notice one of them, which is upon the door of the room
where we are writing. Those hinges termed rising-butts, whose rubbing sur-
faces move in a spiral, or rather a helical line upwards on opening the door,
causes the latter to descend below the level of the carpet, are probably familiar to
enabling it to pass above the carpet on the floor, and which, on shutting the door,
most persons; in that case it will not have escaped their notice that doors so
hung possess this inconvenience, that they will not stand open of themselves,
but are disposed to shut-to, nearly. To obviate these disadvantages, Mr. Redmund
cuts from the helical curves two small horizontal planes, so that they come opposite
to each other when the door is opened so far as to be at right angles to the stile,
that is, having made a quadrant of its circle, at which place the door is conse-
quently at rest, and to shut it when in this position requires a slight pull, which
causes the horizontal plane to slide off its support, and the door then returns by
its descent on the helix. Persons seldom open a door more than 50 or 60° on
entering or leaving a room; consequently, doors hung with these hinges, always
shut when left to their own action, and stand open only when they are turned
to the full quadrant. In some cases Mr. Redmund assists the door to shut—to
closely when opened only a very little way, by the introduction of a very small
spring. A variety of these patent hinges may be seen at the manufacturer's
warehouse in Frith-street, Soho, London.
Having noticed, a few years ago, the inconvenience (attended with per-
sonal danger in some situations) of outside shutters to windows, we contrived
a simple addition to the common outside shutter hinges, which completely
obviated it. Outside shutters when open, are generally fastened back to the
wall by means of those common appendages driven into the wall called turn-
backles, which often become loose, broken, or lost; the consequences of which,
in windy weather, are, not unfrequently broken windows and broken shutters,
besides other inconveniences, which need not be specified. Fig. 1 represents
6
7
6 HINGES.
the ordinary hinge shut: and Fig.2 shows it open. A square hole is cut out
at A, and into it is strongly rivetted a semicircular piece of iron AB, a portion
of it being split in the manner shown, to form it into a spring, and the extremity
Fig. 1. Fig. 2.
*
-------
--
being turned upwards to form a stop, as shown at C. Upon opening the hinge
the flap B passes over the arc, pressing on the spring, and when arrived at the
stop C, it has passed the spring, and is completely open with the shutter fas-
tened flat against the wall. When it is required to close the shutter, the spring
(which is close to the window) is to be pressed down to allow the flap B to come
back over it; and when shut it presents the appearance shown in Fig. 1. These
hinges are manufactured at only sixpence per pair more than the common sort
(the arc being fixed to only the lower one of a pair), and as the troublesome
turnbuckle is thereby superseded, the improvement cannot be considered as
enhancing the expense.
By the ordinary method of
hanging doors to libraries, the
hanging-stiles are fixed to the ver-
tical partitions of the shelves, and
being necessarily of a greater
width than the latter, the books -
behind them cannot be got out | !!!
|
º
|
Ž
|
|
ing. To remedy this inconve-
nience, the following exceedingly
simple and effectual contrivance
has been lately adopted by Mr.
Nettlefold, of Holborn. a is a | * ........... t;
brass plate, which is screwed to |*||
an upright partition; b b are two (1
projecting parts (cast in one piece ©
with a) with the extremities (ii) éjà
rounded off, and perforated to -
receive the centre pin, which & f
passes alike through them and (#3 H (#)
the joint of the common butt- |
hinge c. To the flaps of the latter à
are screwed the doors d and e,
|
without displacing those adjoin-
|
#A
é
É
-
portions of which are only brought |im
into view to save room. It will | | |
be observed that the door e lays
back quite level with the (sup- | | |
posed) shelves, and that the door

HINGES. 677
d folds close against e, so as to lie parallel with it, and quite out of the
way. This being the case, as represented in the figure, it is equally obvious
that when the door d is turned back the contrary way, both doors are thereby
shut, and lie quite flush and close; and that the door e may then in like manner
be folded over d, . The greatest facilities are thus afforded by a single hinge
instead of two hinges, and without the necessity of any additional hanging
stile.
Whitechurch's patent hinge, for enabling doors and windows to be opened
either on the right or left hand, from its utility and convenience, besides the
ingenuity of the contrivance, deserves particular notice. It is equally applicable
to window-sashes, book-cases, and the show-cases of shops; but its advantages
will be most conspicuous in packets, steam-boats, and those situations in par-
ticular where the utmost convenience in a small compass is the object of study.
The engraving on the following page represents the application of the invention
to the sash windows of houses; and its chief utility in these consists in the
facility afforded in cleaning that part of the window in perfect safety which has
heretofore been done at considerable personal peril, and in very many instances
has caused fatal accidents. . Its application to a door is, in principle, the same
as to a sash thus made (which opens on either side like a door); and our descrip-
tion of the hinges and fastenings therefore will, in a great measure, apply to
both. a represents the lower sash, suspended over pulleys by lines and weights
in the usual manner. To open the upper sash b, a false or movable sill is taken
out from the lower part of the sash-frame, which enables the sash a to descend
lower in the frame, and the upper sash, which was previously behind it (or
deeper in the frame) to pass over it, and to swing on its hinges on either side.
At c c c is a pair of long double acting hinges, shown connected on one side of
the window, and separated on the side where the window is open. A pair of
these hinges is shown shut up and complete by the distinct figure d. At ee e
is shown a pair of small auxiliary hinges; and a single hinge of the kind at the
separate figure f shows their precise construction. A brass bolt g is fixed on the
lower stile of the sash, and extending its whole length; about two inches from
the end of the bolt it is jointed, so that when either end is shot into its mortice,
it acts as a kind of support, and as a centre for the lower part of the sash to turn
upon. h h exhibit two small latches for securing or opening the sash on either
side. Now when the window is opened on that side which is at present closed,
exactly the same appearances will be presented, only on the opposite side. It
is therefore clear that the hinges must alternately separate and connect them-
selves at the joints. The manner in which this is done will be partly under-
stood by reference to the separate figure f where each flap of the small
secondary hinges is shown apart, as also their connecting themselves by the
jointed parts of one flap hooking into another. The long hinges used in the
upper part are, however, of a more complex nature, and it is very difficult
to give an intelligible description of them without the aid of several more
figures, giving different views of their parts, which would occupy too much
of our space. Any person, however, who may be desirous of investigating
their principles and mode of action, will, we doubt not, have every facility
afforded them at the office of the patentees. In applying the invention
to a room-door, the arrangement is somewhat different; the long hinges are
placed at top as in the case of the window-sash, and the small auxiliary hinges
are fixed near to the bottom. On the middle stile of the door, the bolt, or
locking bar, is situated, which is either let in flush with the door, or lies in a
mortice passing from one side to the other, and is consequently entirely out of
sight. A mortice lock is placed on each side of the door, for opening and shut-
ting it by means of the knobs, and the bolt springs to and fastens the door
itself, when shut in the ordinary way; and when it is required to open the door
the contrary way to that which it was the last time, an extra half-turn of the
knob throws back the bolt, and locks the opposite side; it is thus opened on
either side instantaneously, and is hung on the opposite side at the same
moment with never-failing security. The door is, in fact, more securely hung,
is better supported, and, consequently, turns on its hinges with greater ease and
4 R
678 HOE.
smoothness. It cannot be taken off its hinges without the aid of a turn-screw,
as in other dools.
| ||
|
HIP ROOF. A roof, the ends of which rise immediately from the wall-
plate, with the same inclination to the horizon as its other two sides. The
backing of a hip is the angle made on its upper edge to range with the two
sides or planes of the roofs between which it is placed.
HIV.E. A receptacle for bees. See BEE-Hive and HoNEy.
HOD. A portable receptacle in which bricks, mortar, &c. are carried by
labourers in house-building. -
HOE. An instrument employed in agriculture in breaking-up earth, an
drawing it around plants. It consists of a broad blade of iron or steel, with an
eye or socket in the middle of its upper side, through which a handle is put.
Garden and field-hoes are generally about three inches deep in the blade, and
from one inch to ten inches in length; but there is a much larger kind, made of









HOLLOW WALL. 679
various forms, equal in dimensions to ordinary spades and shovels, which are
manufactured in this country for colonial use, chiefly for the cultivation of the
sugar-cane. The demand for these articles, not only for the British settlements
but for most other parts of the world, is so extensive as to constitute a con-
siderable manufacture at Bristol, Birmingham, Sheffield, Newcastle, and other
places.
HOGSHEAD. A measure of capacity, or a cask of a certain determinate
size, for holding liquids. The wine hogshead is three-fourths of a puncheon,
one-half of a pipe, and one-fourth of a tun; it contains a tierce and a half, or
63 gallons, or 252 quarts, or 504 pints, or 14,553 cubic inches. The beer and
ale hogshead is half a butt, and contains a barrel and a half, or 3 kilderkins, or
6 firkins, or 54 gallons, or 216 quarts, or 432 pints, or 15,288 cubic inches;
consequently, the wine hogshead is to the beer or ale hogshead as 539 to 564.
There are also hogsheads for sugar, flour, peas, and other dry goods; but of
these the capacities are not fixed.
HOLD. The whole interior cavity of a ship comprehended between the
floor and the lower deck throughout her entire length.
HOLDFAST, Carpenters', is the name of a very useful tool, employed not
only by carpenters, but by other mechanics, for holding fast their work upon
the bench whilst being operated upon. It usually consists of a round bar of
iron, thickening a little upwards, and bent at the upper end, almost into a right
angle, and flattened. An oblique hole is bored in the bench; and if a piece of
wood, or any other article, is wanted to be secured, it is placed under the hold-
fast, and a few strokes of the hammer are sufficient to make it bite firmly. In
order to loosen it, nothing more is necessary than a blow of the hammer
applied at the lower end of the bar.
Mr. W. Dungey, of Compton-
street, Soho, has succeeded in
improving this instrument, for
which he received a reward
from the Society for the Encou-
ragement of the Arts, &c. It
is represented in the subjoined
cut. The jaw a, instead of being
one piece with the rest of the
bar, is movable on the screwed
axis b, and is prolonged back-
wards. In this latter part is a
hole for the reception of a
cranked screw, which bears
on a projection d of the main
bar; e is the hole in the bench,
and f is a flat square piece fixed
by a loose joint to the jaw a, and therefore capable of bearing by its whole
surface on any piece of work placed under it. By turning the screw c in one
direction the work is held fast; and by turning in the other direction it is
released. It is considered as likely to be of service to coachmakers, carvers,
and chair and cabinet manufacturers, as the pressure of it is under perfect
regulation, and it is not liable to bruise the work which it is employed to
hold.
HOLDFASTS. A general term applied to a variety of flat-sided iron spikes,
that are driven into the joints of brick-work, against which it is desired to
fasten any kind of wood-work; for this purpose, the other ends of the holdfasts
are spread out so as to lie flat against the wood, whereto these are nailed or
screwed through holes made in the iron. The term holdfast is likewise applied
to those iron ties in the form of the letter S, which are commonly fixed to walls
to keep the mass from separating.
HOLLAND. A closely woven kind of linen cloth, of a peculiar fabric, so
called from its having been originally imported from Holland.
HOLLOW WALL. A wall built in two thicknesses, leaving a cavity

G$0 HONEY.
between, which may be either for saving materials, or for preserving an uniform
temperature in apartments.
HOLOMETER. A mathematical instrument that serves universally for taking
all measures, both on the earth and in the heavens.
HOMBERG’S PHOSPHORUS. Ignited muriate of lime.
HONE. A fine grained kind of stone, used for sharpening razors, pen-
knives, and other cutting instruments. The exquisite edge given by cutlers to
razors, lancets, &c. can rarely be produced by those persons who are not in the
habit of using them. This arises partly from ignorance of the properties in
which consists the difference between a good and a bad hone, and partly from
a want of that skill and slight of hand in the use of a hone, which long and
constant practice only can give in perfection. Mr. Fayrer, of Pentonville, has,
however, constructed a novel kind of hone, by the use of which the unskilled
and inexperienced operator may, without difficulty, produce a good edge. This
hone consists of a plate of brass a about an inch wide, and of any convenient
length, ground to a perfectly smooth surface on both sides, one of which is
marked R and the other S.; part of each end is cut or filed away, leaving only
two pins or pivots, on which the hone turns or swings. In the frame c c are
two uprights d d, with notches to receive the pivots ; e e are two boxes, one to
hold a coarser and the other a finer powder, made of oil-stone ground down and
washed over: for the latter, finely pulverized water-of-Ayr stone may be sub-
stituted. To use this hone, first place the side marked R. uppermost, and put
on it a few drops of oil and a little of the coarser powder, then draw along it
in the usual manner the edge of the instrument to be sharpened. As the hone
swings on two pivots, the surface necessarily applies itself quite evenly along
the edge of the blade, in whatever direction the pressure of the hand is made
that holds the tool; and the particles of the powder, as the operation pro-
ceeds, are continually becoming smaller and smaller, and therefore giving
a finer and finer edge. To finish the setting, turn uppermost the surface
of the hone marked S, apply to it oil and the finer powder, and proceed as
before.
HONEY. A sweet and scarcely fluid substance, which is collected by
bees from the nectaria of flowers, and deposited in the cells of the combs for
the support of the bees and their offspring. Naturalists are not agreed whether
honey undergoes a particular elaboration in the bodies of bees, thence deriving
its flavour and consistence, or whether it is merely collected and deposited by
them in its pristine state. M. Cavezzali has proved that honey is composed
of sugar, mucilage, and an acid. The sugar may be separated by melting
the honey, adding carbonate of lime, in powder, as long as any effervescence .
appears, and scumming the solution while hot. The liquid, thus treated,
gradually deposits crystals of sugar. There are three distinctions of honey,
according to its purity and the manner it has been obtained from the honey-
combs. The first and finest kind is virgin honey, or the first produce of a
swarm, obtained from the combs without pressing, these being only set to drain,
in order to its running out. The second kind is that known by the name of
white honey, being thicker than the former, and often, indeed, almost solid; it
is procured by pressing the combs, but without the assistance of heat. The
third and worst kind is the common yellow honey, obtained from the combs
first heated over the fire, and then pressed. Honey was a domestic manufac-
ture of great importance before the introduction of cane sugar; and in those
countries where cane sugar is still scarce, the preparation of honey is verv

HOPS. 681
extensively conducted. It is not uncommon for a peasant of the Ukraine to
have 4 or 500 hives; and for a parish priest in Spain to have as many as 5000
hives. In the Hanoverisches Magazin, it is stated that the Jews in Moldavia
have a method of making honey into a hard and white sugar, which is
employed by the distillers of Dantzic, to make their liqueurs. The process
consists in exposing the honey to the frost during three weeks, sheltered
from the sun and snow in a vase of some material which is a bad conductor
of heat. The honey does not freeze, but becomes transparent, and hard as
Sugar. - -
HONEY-COMB. The cellular fabric made by bees in wax, in which they
deposit their honey. Hence, in the casting of iron or other metals, when the
work is not solid, but cellular or spongy, it is denominated honey-comb.
HOOD. A cowl or covering, placed on the top of any thing.
HOOD and MOUTH PIECE, invented by Roberts, the miner, for descend-
ing mines, or going into houses on fire, is described under FIRE Escapes.
HOOFS. The horny substance that covers the feet of various animals; it
chiefly consists of coagulated albumen. See HoRN.
HOOP. A pliant piece of wood or metal made into rings, or circular ban-
dages for casks, &c.
HOPPER. A trough or funnel employed to supply corn to a mill, fuel to
close furnaces, and to a great variety of other purposes.
HOPS. The dried flower buds of a British climbing plant, which grows
wild in many parts of England; but for the purposes of commerce and brewing,
they are usually cultivated in extensive plantations, where they require the
growth of some years before they attain perfection. To cultivate it with suc-
cess requires extreme care, considerable experience, and a large capital; yet
perhaps of no plant is the harvest so precarious, from an unfavourable season,
and the depredations of insects. There are several varieties of it, as the red
bind, the green bind, and the white bind. It is propagated by nursery plants,
or by cuttings. These are planted in little hillocks, formed by digging a hole
12 inches deep and 18 inches in diameter, and filling it up with fine mould, mixed
with manure, and the original soil. In the centre of the hill is set a single
plant, and round it half a dozen others. The hills are about 9 feet asunder.
Cuttings are set in February and March, but sets, or nursery plants, in autumn.
In April, if the season be favourable, the binds require tying to poles, which
are stuck in the earth. About Midsummer they are pruned, and the produce
given to cattle. In September they are usually ready for pulling. Chestnut
is reckoned to make the best poles, and ash the next—the poles are from 18 to
24 feet in length; three poles are sufficient for a single hill, or two poles where
the plants are vigorous. The large poles are not required till the first winter
after the plantation has been formed, and it is advisable not to take any produce
the first year. The picking is performed by men, women, and children.
Proper baskets and bins or cribs being in readiness, the plants are cut off close
to the ground, and the poles drawn up; these are placed upon the bins, with
the plants upon them, and three or four persons on each side piek off the hops.
After this, they are dried in a kiln; and when dry they are carried into, and
kept for five or six days in a room called the stowage room, until they are in
a state to be put into bags. This is done through a round hole or trap, cut in
the floor of the stowage room, exactly equal to the dimensions of the mouth of
the bag, and immediately under which, to a frame of wood, this mouth is fastened.
In each of the lower corners of the bag a small handful of hops is tied ; and a
person called the packer places himself in it, and by a heavy leaden weight,
which he constantly moves round in the places where he is not treading, presses
and forces the hops down in a very close manner into the bag, so fast as they
are thrown to him by another labourer. The work thus proceeds until the bag
is quite full, when each of the upper corners has a few hops tied in it in the
Same Iſlall Il 61'.
. The usual way of extracting hop poles, by pushing them backwards and for-
wards till they are sufficiently loosened to be raised up out of the ground by
hand, subjects the hops to injury, by shaking and bruising them, while the poles
682 HORN.
themselves are frequently broken. These inconveniences are avoided, and a
considerable time is saved, by the application of an apparatus invented by Mr.
John Knowles, of Farnham, who took out a patent for it in 1830. The nature
of the contrivance, and the intention of the inventor, are well expressed on the
title of the patent, which is for “a certain instrument or machine for drawing
up hop poles out of the ground previous to picking the hops, and which, by
drawing the poles perpendicularly, will greatly save them, as well as prevent
the hops from being bruised, called a hop-pole-drawer, by lever and fulcrum.”
In the annexed engraving, Fig. 1, is shown a portion of a hop pole, and the appli-
cation of the lever and fulcrum in raising it out of the ground; a a is the pole
Fig. 2.
(4
º
b the lever, and c is its fulcrum, which has a broad base, with a short spike
to prevent its slipping when the pressure is applied to it. Fig. 2 shows a plan
of the lever with its iron jaws, which are made to approach each other, that
some part of the opening may fit all sizes of poles; and they are serrated to
prevent their slipping upon the poles.
HORN. An animal substance, composed of coagulated albumen, with a
little gelatime, and about a two-hundredth part of the phosphate of lime. But
the horns of the buck and hart are of a different nature, being intermediate
between bone and horn. The horns of oxen are prepared for lanthorn leaves
in the following manner. They are first softened by roasting over a fire made
of the stalks of furze, and then slit lengthwise, on one side, and kept expanded
flat between a pair of tongs, and afterwards placed in a press between iron
plates that are greased. Here the horns remain till they are cooled; they are
next soaked in water till soft enough to be pared down to the required thinness,
with a large knife worked horizontally on a block. Their transparency is
thus acquired ; and after being immersed in ley, they are polished with
whitening, and the coal of burnt willow. Horn for making into snuff boxes,
combs, and other ornamental articles, are stained to imitate Tortoise SHELL,
which see.
HORN. A musical instrument of the wind kind : the earliest, from which
the instrument derived its name, were the horns of animals, and these are still
used extensively in remote or uncivilized districts. Considered as a modern
musical instrument, they are chiefly made of metals, and of various kinds or forms.
The French horn is a long tube, narrow at the top, and increasing in diameter
to the end, where its mouth is very wide. It is curled up in several rings, for
the convenience of carriage and performance. The trumpet and the bugle
horn are noticed under their respective heads.

HOROLOGY. 683
HORN, ARTIFICIAL, or TANNED GELATINE. Considerable manufactories
have, it is said, been established in France, for the construction of a variety of
articles with this substance. . The gelatine is usually obtained from bones, by
treating them with a weak solution of muriatic acid; and it is afterwards tanned
by the common process, as in making leather. Upon becoming hard and
dry, it assumes the appearance of horn or tortoise shell, and is employed
for the same purposes as those substances. It is softened by being boiled
in water with potash, when it may be formed into any shape, and the figure
preserved by drying the articles between moulds. In the soft state, it may
also be inlaid with gold, silver, or other metals, and is streaked with various
coloured materials, so as to resemble the finest woods and other natural pro-
ductions. -
HORNBLENDE. A species of the clay genus, of which there are three
varieties; viz. the common, hornblende slate, and basaltic hornblende.
HORN-ORE. One of the species of silver ore.
HORNSTONE. A sub-species of rhomboidal quartz, according to
Jameson, who divides it into splintery hornstone, conchoidal hornstone, and
woodstone. **
HOROGRAPHY. The art of DIALLING, which see.
HOROLOGY. The art of constructing machines for measuring time; but
from the circumstance of clocks and watches having very generally superseded
all other contrivances for this purpose, the term is now usually understood as
referring to these latter instruments solely. In these machines a pendulum, or
a spiral spring, connected to a flat wheel turning freely on its axis, (called a
balance wheel,) is made to vibrate; and it being a property of these bodies,
that all the vibrations, whether through large or small arcs, (within certain
limits,) are made in equal times, all that is necessary to measure time by this
means, is to register the vibrations, and to prevent the vibrating body from
being brought to rest by the resistance of the atmosphere, or the friction of its
parts, about the centre of oscillation; and these objects are effected by means of
a train of wheels put in motion by the descent of a weight, or by the action of
a coiled spring, the velocity of the wheels being regulated by the vibrations of
the vibrating body. The essential difference between clocks and watches con-
sists in the nature of the regulator employed; which in clocks is the pendulum,
and in watches the balance wheel. The pendulum requires to be suspended from
steady points of support, that its vibrations may be constantly performed in a
vertical plane, hence clocks cannot be made portable; but from the pendulum
being acted upon by the force of gravity, which is a constant force, its motion is
more equal than that of the balance spring, the force of which varies greatly,
from changes of temperature, and other causes; clocks are therefore always
preferred in observatories; but as the balance will perform lying in any position,
watches have the advantage of being portable.
We shall now proceed to describe the construction of an ordinary eight-day
clock, which we hope will be rendered sufficiently clear with the help of the
accompanying engraving, which exhibits a front view of the works, the dial
plate being removed to show the manner in which the hour and minute hand
are made to revolve with different velocities upon the same centre. A portion
of the front frame plate is likewise represented as broken away to exhibit more
clearly the escapement; the striking parts, and the wheels and pinions com-
posing the train, being hidden by the frame plate, are represented simply by
dotted circles, and instead of letters of reference, they are indicated by figures,
which express the number of teeth contained in them. The striking parts, as
usually constructed, are so very complex as to render it extremely difficult to
convey a clear idea of their operation without a very lengthened description, and
several diagrams; we have therefore preferred introducing in their stead an
extremely simple and ingenious arrangement for the purpose, invented by Mr.
Prior, of Nessfield, in Yorkshire, and for which he received a reward from the
Society of Arts. A clock of this kind contains two independent trains of
wheelwork, each with its separate first mover; one is constantly going to indi-
cate the time by the hands on the dial plate; the other is put in motion every
684 HOROLOGY.
hour, and strikes a bell to tell the hour at a distance; the dotted circle a is the
barrel of the going part; it has a catgut b wound round it, suspending the
weight c which keeps the clock going; 96 is a wheel (called the first or great
wheel,) of that number of teeth, upon the end of the barrel, turning a pinion
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of eight leaves, on an arbor which carries the minute hand. 64 is a wheel of
64 teeth, on the same arbor, (called the centre wheel,) turning the wheel 60, by
a pinion of eight leaves on its arbor: this last wheel gives motion to the pinion
of eight, on the arbor of the swing wheel 30, of 30 teeth; d h are the pallets of
the escapement, fixed on an arbor e, going through the back plate of the clock's
frame, and carrying a long lever, which has a small pin projecting from its





HORO LOGY. 6öö
lower end, going into an oblong hole, made in the rod f of the pendulum. The
pendulum consists of an inflexible metallic rod, suspended by a very slender
piece of steel spring, from a brass bar, screwed to the frame of the clock, having
a weight or bob at its lower end, in the present case 39.125 inches from the
point of vertical suspension; when this pendulum is moved from the line in
either direction, and suffered to fall back again, it swings nearly as much beyond
the vertical on the contrary side, and then returns; this it will continue to do
for some time, and each of these vibrations will be performed in one second of
time, when the pendulum is of the above length. This is the measurer of the
time; and the office of the clock is only to indicate the number of vibrations it has
made, and give it a small impulse each time to keep it going, as the resistance of
the air, and elasticity of the spring, would otherwise in a few hours cause it to
stop. By the action of the weight applied to the cord b, (which is called the
maintaining power,) the wheels are all turned round; and if the pallets dh were
removed, the swing wheel 30 would revolve with great velocity in the direction
from 30 to d, until the weight reached the ground ; the teeth of these pallets
are so made that one of them always engages the wheel, and prevents its turn-
ing more than half a tooth at a time. In the drawing, the pallet d has the
nearest tooth of the wheel resting on it, and the pendulum is on the side h of
the perpendicular; when it returns it moves the pallet d so as to allow the
tooth of the wheel to slip off; but in the mean time the pallet h has interposed
its point in the way of the tooth next it, and stops the wheel till the next vibra-
tion or second; the distance between the two pallets dh is so adjusted that only
half a tooth of the wheel escapes at each vibration; and as the wheel has 30
teeth, it will revolve once in 60 vibrations of one second each, or one minute;
consequently a hand on the arbor of this wheel will indicate seconds on a circle
on the dial plate divided into 60; the pinion of eight on its arbor is turned by a
wheel of 60, which consequently will turn once in seven turns and a half of the
other, or in seven minutes, 30 seconds, or one-eighth of an hour; its pinion of
eight is moved by a wheel of 64, or eight times itself, which will turn in one-
eighth part of the time, this will be an hour; the arbor of this wheel, therefore,
carries the minute hand of the clock. The great wheel of 96 being twelve times
the number of the pinion eight, will turn once in 12 hours, and the barrel a
with it. The catgut goes round 16 times, so that the clock will go eight days.
The hour-hand of the clock is turned by the wheel work shown upon the front
frameplate; on the end of the arbor of the centre wheel 64 a tube is fitted, so
as to go round with it by friction; this carries the minute hand, but if the clock
should require correction, the hand may be slipped round without moving the
wheels: this tube has a pinion of 40 teeth -on its lower end, indicated by a
dotted circle; this turns another wheel 40, of 40 teeth, which has a pinion of 6
teeth on its arbor, turning a wheel 72, of 72 teeth; the two wheels 40 will both
turn in an hour, and 72 in 12 hours; the arbor of this wheel has the hour-
hand, and is a tube going over the minute-hand, so that the two hands are con-
centric. The barrel a is fitted to an arbor coming through the plate of the
clock, and is filed square to put on a key to wind up the weight; the great
wheel 96 is not fixed fast to the arbor, but has a click on it, which takes the
teeth of a ratchet wheel cut upon the barrel; so that the barrel may be turned
in the direction to wind up the weight without the wheel; but by the descent
of the weight, the wheels will be turned by the click.
In commencing our description of the striking parts, we should observe, that
Mr. Prior not having exhibited their connexion with the going parts of a clock, we
have chosen the mode of unlocking the detent which appeared the simplest, and
admitted the easiest explanation; but various other and perhaps better modes
might be contrived for effecting this: the dotted circle k has a weight m sus-
pended from it by a catgut passing round it like that which passes round the
going barrel a , n is a scape-wheel of 78 teeth, connected with the barrel by a
ratchet and click, and having 12 pins projecting from its face, a portion of
which are seen, marked 2, 3, 4, 5, 6, 7, 8; these pins are ranged in a circle at
unequal distances, corresponding to the number of strokes to be struck at each
4 s
686 H() f.O.F.C. (; Y.
successive hour; o is the scapement similar to that previously described; on
its arbor is fixed a pendulum p, of about nine inches in length, and which will
therefore vibrate half seconds nearly: but in order to regulate the rate of
vibration at pleasure, the rod of the pendulum is prolonged beyond the point of
suspension, and carries a small ball q moving stiffly upon it, and by raising or
lowering this ball the vibrations become retarded or accelerated. To the lower
end of the pendulum rod is attached a hammer r, which strikes upon a bells at
every second vibration; this effect is obtained by placing the bell sufficiently
oblique to allow the hammer to swing past it at one vibration, and to impinge
upon it at the returning one. The barrel k and escape-wheel n are retained at
rest by the locking detent t, which engages each of the pins in succession on
the face of the escape-wheel; this detent is fixed on to the arbor of the arm or
lever v, which is pressed by the spring w against a snail or cam a fixed upon the
hollow arbor which carries the minute-hand. The snail is consequently carried
round once in an hour, during which time the lever v is gradually elevated, and
moves the detent in like manner until the lever arrives at the highest part of
the snail, when the pin on the escape-wheel is released from the detent, and the
wheel immediately begins to revolve and imparts motion to the pendulum, which,
as before said, strikes upon the bell at each second vibration. The rotation of the
snail having carried its highest point past the end of the lever, the latter
(pressed by the spring wy falls past the straight side of the snail to the foot of
the same, and brings the detent into its locking position; and when, by the
revolution of the escape-wheel, the next pin comes in contact with the detent,
the motion of the wheel is arrested. Clocks are sometimes impelled by springs
instead of weights, as in the one just described, and are very convenient for
placing in chambers on account of their occupying less room than weight-
moved clocks. The construction of these spring clocks resembles that of the
other, with the exception that for the oarrel and weight are substituted a fusee
and spring barrel, resembling the same pieces in a pocket-watch, to the descrip-
tion of which we shall now proceed. -
The essential difference, as we have before observed, between a clock and a
watch, consists in the former being regulated by a pendulum, and the latter by
a balance; for as to the maintaining power, it is sometimes the same in both,
since although watches are not impelled by weights, clocks (as just mentioned)
are sometimes kept in motion by springs like watches. The balance is a small
wheel fixed on an arbor or axis called the verge, and moving freely upon pivots
at the ends of the arbor. To the axis of the balance the inner end of a very
elastic helical spring called the pendulum is attached, and the outer end is made
fast to some fixture. In this state the balance will remain at rest when the
spring is in that position which it would assume if detached from the balance,
and at perfect liberty; but if the balance be turned on its pivots in either
direction, so as either to wind up or unwind the spring, the latter will, upon
the external force being removed, tend to resume its natural position ; but the
momentum which is thus imparted to the balance will carry it past the position
of rest, which will again alter the spring, and the balance will again be returned
past the position of rest, and will thus continue to vibrate until the friction of
the pivots and the resistance of the air destroy the original impulse. The
vibrations of such a balance, which passes through equal spaces, will be per-
formed in equal times; these vibrations, therefore, form the real measure of
time, and the remaining apparatus in a watch is for the purpose of registering
the vibrations, and of maintaining the motion of the balance; and this is
accomplished in watches by means of a train impelled by a spring and fusee.
The spring employed for this purpose consists of a long flat plate of steel, coiled
up in a helical form; it is inclosed in a cylindrical box called the spring barrel,
to which its external extremity is attached, whilst its internal end is connected
to a fixed axis, round which the barrel revolves. As the strength of the spring
is greater the more it is coiled up by turning the box, its action would be
unequal in impelling the work of the clock; and to remedy this inconvenience,
the fusee has been contrived. The fusee consists of a conical barrel, round
HOROLOGY. 687
which a spiral groove is cut, which receives a chain previously wound round
the barrel, by which, as it is turned round, it coils up the spring; the groove
receives the chain first near the base of the cone, and as the barrel revolves,
gradually brings it nearer the axis; by this means the stronger the spring is
coiled up, the shorter is the lever by which it acts upon the work; and as it
gradually uncoils and becomes weaker, on the contrary the lever of action
becomes longer.
Having thus explained the nature and operation of the regulator, and of the
maintaining power, we shall endeavour to describe the construction of an ordi-
nary watch, with the assistance of the annexed engravings. Fig. 1 represents
3. - Wi
-
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º i
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i
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the works, the upper plate being removed; Fig. 2 is the upper plate, with the
cockremoved to show the balance; and Fig. 3 a general elevation, supposed to be
set out upon a straight line, in order to show the whole at one view. The same
letters of reference are used to denote the same parts in all the figures. 6. "
the spring barrel; b the chain attached by one end to the barrel, and after
being wound several times round the barrel, hooked by the other end to the
fusee c, mounted on pivots turning in holes in the two plates e ex one of these
pivots f projects a considerable distance, and is cut square to receive a key, by
turning which the fusee is turned round so as to wind the chain upon it, which
causes the spring barrel to revolve also, and coils up the spring into a closer
spiral than it was when at liberty; and upon the key being removed, the spring
reacts upon the chain, and by that means turns the fusee. To prevent OV elſ-
winding, a guard is added, which consists of a small lever 9, which, when the
fusee has received a certain number of turns of the chain, presses against, *
stop h on the top of the fusee. k is the great wheel attached to the base of the
fusee by a ratchet and click, by which means the fusee can be wound up with-
out turning the great wheel; this latter has 48 teeth, and turns a pinion of 12
teeth on an arbor in the centre of the watch, which carries the minute-hand.
upon this arbor is fixed the centre wheel m, of 54 teeth, working in a pinion
fixed upon the arbor of the third wheel, n, of 48 teeth, which turns the
pinion of the contrate wheel o, of 48 teeth; the contrate wheel gives motion




































688 HOROLOGY.
to a pinion of 6 teeth, which is fixed upon the arbor of the crown or balance-
wheel p, which has 15 large teeth, that stop against two pallets alternately
upon the verge or arbor of the balance q ; these pallets are two small teeth
projecting from the verge at nearly right angles to each other, and constitute
the escapement, the object of which, as in a clock, is to prevent the train run-
ning down rapidly by the action of the main spring, as would be the case if
there were no check to it; but at each vibration of the balance, one of the
pallets engages a tooth of the crown, thereby retarding the motion of the train,
and imparting fresh impetus to the balance; and no sooner has the pallet
swung clear of the tooth, but the other pallet engages another tooth on the oppo-
site side of the wheel. One of the pivots of the balance works in a small
frame r called the potence; the lower pivot of the verge works in it also, and
the upper pivot turns in a cock s screwed to the plate e. The minute-hand t is
fixed upon the outer end of a tube which fits tight upon the arbor of the cen-
tral wheel, and which carries upon its inner end a pinion of 12 teeth; this
pinion turns a wheel v of 48 teeth, on whose arbor is a pinion of 16 teeth
turning another wheel of 48 teeth, the arbor of which is a tube fitting upon
the other tube on the central arbor, and carries the hour-hand w. The tension
of the main spring is adjusted in the first instance by the maker, who turns its
arbor, on the head of which is fixed a ratchet y, in which a click takes and
thereby holds it fast when wound up to the proper pitch; subsequently, when
a watch is perceived to gain or lose time, it is regulated by strengthening or
weakening the pendulum spring 1, Fig. 2, which will cause it to move quicker
or slower. This adjustment of the pendulum spring is effected thus: the spring
is fixed to a stud 2 upon the plate e by one end, and to the verge of the balance
by the other; 3 is a lever lying betwixt the spring and the plate, and turning
in a collar in the plate concentric with the centre of the balance, the verge of
which passes through a hole in the lever; upon the lever is fixed a small stud
4 with a notch in it to receive the spring; the acting part of the spring is from
4 to the centre, therefore by turning the lever in either direction, the length of
the spring is altered, and in order to regulate this length with precision, the arc
through which the end of the lever can be made to traverse on the plate, is
divided into a number of equal parts or degrees. In Figs. 1 and 3 are shown
four pillars, by which the two plates of a watch are held together; and in
Fig. 2, the heads of the same pillars are represented coming through the
upper plate, with small pins put through them to keep the plate down.
Chronometers are portable time-keepers, in which, by the nature of the
escapement, and the compensations for heat and cold, mean time is kept with
sufficient accuracy to determine the longitude at sea. The relation between
time and longitude, will be found explained under the head LoNGITUDE. As
the principal differences between chronometers and other watches consist in
the escapement and the balance, we shall not detain the reader with a descrip-
tion of the other parts of these machines, but shall proceed to describe more
fully the various modes of constructing those grand essentials in all time-
keepers, the regulator and escapement, noticing particularly those employed in
chronometers.
Amongst the various steps by which horological machines were brought
to their present state of perfection, the most important is the addition of the
pendulum, which furnishes at once the most simple and accurate measure of time
that we are yet acquainted with. Various claims have been made for the honour
of this grand improvement, but the person to whom mankind is really indebted
for bringing it into universal notice, is the celebrated Christian Huygens, of
Zuylicherh, who, in his excellent treatise De Horologio Oscillatoreo, has described
the construction of a pendulum clock, and proved that he made one before the
year 1658. His method of supporting the pendulum in the figure, on the
following page, in which a contrivance is resorted to for the purpose of insuring
its isochronous motion, is ingenious, although it is not quite correct, as
has been shown by Mr. Cummings, in his Treatise on Watch-Making. It
consists of two cycloidal cheeks of brass, forming a curve, in which the
HOROLOGY. 689
silk line by which the pendulum is suspended moves. When
the art of clock-making had attained a high degree of perfec-
tion, and the application of this instrument to astronomical
observations rendered the utmost accuracy desirable, it was soon
perceived that the varying length of the pendulum rod, in con-
sequence of its expansion by heat, and contraction by cold,
was a source of irregularity, which it was deemed difficult to
overcome. To diminish as much as possible these variations,
we are indebted to that eminent artist, George Graham, for
the first application of the principle, which, under various
modifications, has since been applied to preserve unchanged the
centre of oscillation in a pendulum, and thus to insure the
performance of all its vibrations in the same length of time.
Those substances which were found to be least alterable by
changes of temperature, such for example as wood, and par-
ticularly deal (pine), were employed in the best clocks. As
the different metals are affected by heat in different degrees,
Graham conceived the idea that the greater expansion of one might he
employed to counteract the less expansion in another. After a series of trials,
during a period of five or six years, he succeeded perfectly, by attaching to the
pendulum rod a vessel containing mercury, which liquid, when the rod was
expanded by heat, rose, from the same cause, in the vessel which contained it,
so as to compensate for the downward expansion of the rod. This improvement
was completed in the year 1721. Five years afterwards John Harrison, a car-
penter in Barton, in Lincolnshire, subsequently so celebrated for his improve-
ments in chronometers, invented and applied to a clock of his own manufacture
the pendulum, which from its form is called the gridiron pendulum. In this
the expansion of the iron rod is corrected by the greater expansion of rods of
brass or of zinc, which tend to raise the bob in the same degree in which the
expansion of the main rod tends to lower it, and it of course is retained in the
same place : in this form the compensation pendulum is, to the present day,
most commonly made. The principle upon which these pendulums were con-
structed has received various modifications in the hands of different artists;
Harrison's rods, for example, instead of being arranged in the form of a
gridiron, have been inclosed in a tube, and greater elegance and compactness,
with a more easy mode of adjustment, have been attained; these, however, we
believe, comprise the whole merit of the
modern improvements.
The annexed figure represents the mode
of compensation proposed by Dr. Fearn. a
is the pendulum rod suspended by a flexible
spring, in the usual manner, from the cock w
b; c is a rod or bar of zinc attached to the
|
back plate of the clock, by a screw at its
lower end. The head d of this bar works
upon a pin, which forms a joint, as repre-
sented in the drawing. Through this head
there is a mortice, which allows one end of
the lever ee to pass through it, and within º
which it may be fixed firmly by means of a a'. .
|
tightening screw. The lever e e is attached
to the clock-plate by a screw, which is also
its fulcrum. Through a slit in the inner
end of this lever the suspending spring
passes, and is closely embraced by it on its
lower side. The operation of this apparatus
will readily be conceived ; as the rod a |
lengthens by heat, or contracts by cold, the ©
rod c will be similarly affected. The expan- &^2/
sion of c will cause the inner end of the º


690 HOROLOGY.
lever to descend, and, consequently, to embrace the suspending spring at a
lower point, and thus to diminish the effective length of the pendulum. The
mode of adjustment is obvious, as a greater or lesser motion may be given to
the lever, the upper end of the rod c being made to approach or recede from
its fulcrum. To obtain the requisite accuracy, an adjusting screw may be made
to act upon the head d. © º e
In the year 1818 a reward was given to Mr. Reid for a compensation pen-
dulum, in which the bob rested in a hollow cylinder of zinc, through which the
rounded end b c of the steel pendulum rod is passed,
the zinc itself being supported by the nut e at the
end of the rod. As, therefore, the rod lengthened
by heat, carrying the bob downward, so the upward
expansion of the zinc raised the bob; and if the rela-
tive lengths of the steel and zinc were so propor-
tioned that the amount of their expansions was
equal, it is evident that the compensation above
described would be perfect; but it is extremely
difficult to effect this accurate proportioning of the
lengths of the two metals. The length of the zinc
at first must be such that its rate of expansion shall
be in excess, and it must be cautiously reduced by
repeated trials till the requisite accuracy is attained;
this, however, is not done, except at a considerable
expense of time and attention, to avoid which Mr.
Reid has introduced the following modification.
He forms a hollow screw in the cross bar f of the
bob g, and an external screw on the same rake on
the end of the zinc cylinder d, this latter is pur-
posely made too long for due compensation, but its
effective length may be commodiously and accu-
rately reduced to what is required by screwing it
up as represented in the figure; but after this has
been done, supposing the nut e to have remained
stationary, it is evident that the extent of gravity of
the pendulum itself will have been lowered by the
bob descending exactly as much as the upper end
of the cylinder has advanced through the hole in
the cross-bar f; an adjustment for time is therefore
required after that for compensation has been
effected, which is done in the usual way, by screw-
ing up the nut e. This latter compensation, how-
ever, will not be required, if the rakes of the screws f and c are proportionate
to each other, as the weight of the bob alone is the sum of the weights of the
bob, the zinc cylinder, and the nut. Thus, if the former weight be assumed as
ten, and the latter as eleven, the screw at f must have ten
threads, in the same length that the screw at c has eleven i-2
threads. Care must be taken in screwing the cylinder of zinc .
up or down, to place the finger and thumb at the same time |
on the nut, so that the two may turn together; or the nut
may be fastened to the cylinder.
In connexion with this branch of the subject, we may notice
the inverted spring pendulum, invented by Mr. W. Hardy, of
Wood-street, Clerkenwell. The object of this invention is to
ascertain the stability of the support of clocks, for which pur-
pose the weight at its upper extremity is screwed down until
it will perform its vibrations in the same period of time as the }
pendulum of the clock. The inventor states that when the |
weight a is screwed up to the top of the steel rod b, it
vibrates only once or twice in eight or nine seconds, which |
renders it remarkably susceptible, and that its sensibility is
|


HOR OLOGY. 691
so great that the attraction of the sun and moon, or of mountains, may be
observed by it : it serves also for ascertaining the stability of buildings. a is
the weight screwed upon a steel rod b, which is supported at bottom by a small
piece of steel watch-spring c, and contained in a glass tube; d is a cap or
stopper to the upper end of the tube, and carrying underneath a small gra-
duated scale, over which ranges the index at the top of the weight. For this
invention Mr. Hardy received a reward from the Society of Arts. His com-
munication to them was accompanied by testimonials to the value of the inven-
tion from several eminent scientific characters, amongst whom was Captain
Kater, who employed the instrument to assure himself of the stability and
freedom from tremor of the base upon which his clock rested during his
experiments.
Before the application of the pendulum as a regulator in clocks, balances had
been employed for that purpose, but were quickly superseded after the intro-
duction of the pendulum; but as external motion is destructive of the regularity
of the pendulum's performance, the balance was still the only regulator which
could be applied in portable machines, and the great improvement made in
that regulator by the addition of a spring has caused it to approach the pen-
dulum in point of correctness. The first invention attaching a spring to give
to the balance, by its elasticity, a power which renders the action of this sort
of regulator similar to that of gravity in a pendulum, is undoubtedly due to
Dr. Hooke, but he appears to have applied it only in a straight form. Huygens,
improving upon this idea, substituted a spiral spring, which is much more
favourable to the vibrations of the balance.
The alterations to which the length of the pendulum is exposed by variations
of temperature, and which affect the going of clocks, have already been noticed;
but watches with a balance are still more exposed to irregularity from that
cause, as not only the balance expands or contracts according to the rise or fall
of the thermometer, but the regulating spring itself suffers the same changes.
As the balance contracts, and its diameter becomes less, it will be more easily
carried round by the vibrating forces, and will then vibrate more quickly; and
as the spring attached to the balance becomes contracted at the same time, it
will likewise act with greater force when cold, and on this account the vibra-
tions will be farther quickened. There are two ways of correcting these irregu-
larities; the first, which was invented by Harrison, consists in lengthening or
shortening the spring when heat or cold may have given it more or less force;
the other method is to cause the balance to expand instead of contracting by
cold, by which means the spring, when in the state of great rigidity, has more
work to do; this method originated with Peter Leroy, and has since been
carried to great perfection by Arnold. Harrison (whose application of the dif-
ferent expansion of two metals to correct the variations in the length of the
pendulum, has been already noticed), applied the principle in a manner not
before thought of, and made it act on the spiral spring so as to produce the
desired compensation in the regulator. His method is described as follows,
(Principles of Mr. Harrison's Time-keeper, p. xii—Notes.) “The thermometer
kirb is composed of two thin plates of brass and steel, rivetted together in
several places, which, by the greater expansion of brass than steel by heat and
contraction by cold, becomes convex on the brass side in hot weather, and con-
vex on the steel side in cold weather; whence, one end being fixed, the other
end obtains a motion corresponding with the changes of heat and cold, and the
two pins at the end, between which the balance spring passes, and which it
alternately touches as the spring bends and unbends itself, will shorten or
lengthen the spring, as the change of heat or cold would otherwise require to
be done by hand in the manner used for regulating a common watch.” This
method of effecting the compensation, although it evinces considerable inge-
nuity, is now seldom used, owing to the extreme difficulty of effecting an accu-
rate adjustment; recourse is therefore had to the principle introduced by
P. Leroy, a modification of which is seen in the figure on the following page,
which represents the balance of a chronometer as commonly constructed. A
circular groove is turned in the flat face of a piece of steel, and into this groove
692 HOROLOGY.
a piece of good brass is driven, and a little of the solution
of borax is applied to prevent oxydation. This compound &
piece being then put into a crucible, is made sufficiently
hot to melt the brass, which in these circumstances ad-
heres firmly to the steel without requiring any solder. o
The face of the steel is then cleaned, and by proper appli-
cation of the mechanical means of turning, boring, and & 3"
filing, the superfluous steel is taken away, and the balance
is left, consisting of two, or sometimes three, radii, and a
rim, the external part of which is of brass, and the internal part of steel, the former
metal being about twice the thickness of the latter. In this state the arms of
the rim are then cut through and diminished in their length, as in the figure;
and near that extremity of each arc which is farthest from its radius, is put on
a piece or weight, which can be slided along the arm, so as to be adjusted at
that distance which shall be found, upon trial, to produce a good performance
under the different changes of temperature; the flexure of the arms by the change
of temperature carrying the weights nearer to the centre in hot than in cold
weather, and the more the greater the distance of the weights from the radius.
The small screws near the ends of the radii afford an adjustment for time, as
the balance will vibrate more quickly the further these are screwed in ; and the
contrary will be the case if they be unscrewed or drawn further out.
The accompanying cut shows a balance according to the construction of
Arnold, and specified by him to the com-
missioners of longitude. The expansion
weights are cylindrical, and are adjusted
upon the arms by screwing; and there is
an inner rim, upon which three weights are
adjusted by sliding, which serve to regulate
the going of the time-piece in different posi-
tions. The necessity of a different adjust-
ment of the balance, according as the balance
is to vibrate with its axis vertical to the
horizon, or parallel to it, will be obvious
when we consider that the pivots of the axis
bear, very differently according to the position of the chronometer; and it
requires some management to make the frictions the same, whether the axis be
turning upon one of its ends, or upon the two cylindrical faces of the pivots;
and still more than this, since the balance itself has a permanent figure com-
pared with the spring, which, in every part of its vibration, alters its distance
from the axis, and in every part of its length has a different degree of rotatory
motion ; it cannot be expected, nor does it happen, that a balance, which is
found to be in poize along with its spring when out of the chronometer, will
make equal vibrations, as to time, in all positions when in its place; and in
addition to these difficulties, there is one part of the vibration where the force
of the spring and the inertia of the balance are not simply in opposition to
each other, but are combined with the maintaining power, viz. during the action
of the escape. The remedy for all these difficulties, which is happily adopted
in chronometers for use at sea, is to place the axis in a vertical position, by
which means the balance itself is not affected by gravity; but for pocket time-
pieces, the ingenuity of the artist is called upon for expedients of which it
would not be easy to exhibit a complete theory. The general principle com-
monly used, is to consider the balance, when out of adjustment for position, as
a pendulum when above and below the centre of suspension, acted upon by
gravity, and, at the same time, urged to a quiescent point by the force of elas-
ticity. In these circumstances the vibrations will be quickest when the point
of stable equilibrium is downward, and they will be slowest in the opposite
positions of the machine. This leads to the remedy of diminishing either the
radius or the weight on that side which is lowest when the rate is most quick.
Thus, if one of the two adjusting screws in the first of the preceding balances
were downwards in the position of quickest rate, that screw would require to

HOROLOGY, 693
be screwed a very little quantity inwards, and the opposite screw to be screwed
a like quantity outwards, in order to remedy this imperfection without much
alteration of the other adjustments. And if a like imperfection were found in
the vibrations of the balance when tried in a vertical position, having the lowest
point at rest in a line at right angles to a line passing through the radii, a
similar alteration must be made in the expansion weights, either by a careful
flexure of the circular arcs, or by altering the quantities of those weights; or
else by means of small circular screws tapped into the weights themselves, and
directed towards the centre like the weights at the extremities of the radii. By
these, and other correspondent means, the balance may be made to keep time
in all those positions wherein its plane shall be perpendicular to the horizon;
but even in these trials very great pains and labour may be required to produce
a high degree of accuracy; and, after all, as the quantity of action in the
spring must alter the quantity of pendulous effect in this curious and delicate
time measurer, it may be doubted whether the adjustments for position in the
vertical balance can be effectual any longer than while the arcs of vibration
remain the same. This consideration points to the necessity of an adjustment
in the maintaining power, in order that the vibrations shall not fall off; the
means of effecting this will be shown in treating of the different sorts of escape-
ments, to the consideration of which we shall now proceed.
The escapement is a general term for the manner of communicating the
motion of the wheels to the pendulum of clocks or balance of watches. One
of the most ancient escapements is that which is now applied in almost all
common pocket watches; it is represented in Fig. 1, and is best suited to the
long vibrations of the balance, which was invented earlier than the pendulum.
a b denotes the rim of a contrate wheel, Fig. 1.
called the crown wheel, having its teeth
pointed and sloped on one side only, so that 21-->

the points advance before any other part of
the teeth during the motion. c and d are
two pallets or flaps, proceeding downwards
from the verge ef. The pallets are nearly
at right angles to each other; and when t A-. Af
the balance fg, fixed on the verge, is at inſſº, Dºº
rest, the pallets remain inclined to the plane ºf: Cl
of the wheel, in an angle of about forty- esºłº
five degrees; but when it is made to vibrate, ſ
one of the pallets is brought nearer to the
perpendicular position, while the other becomes more nearly parallel. The wheel
must be supposed to have one of its teeth resting against a pallet by virtue of
the maintaining power. This tooth will slip off or escape as the pallet rises
toward the horizontal position, at which instant a tooth on the opposite side of
the wheel will strike against the other pallet which is down. The returning
vibration, by raising this last pallet, will suffer that tooth to escape, and another
tooth will apply itself to the first-mentioned pallet. By this alternation, the
crown wheel will advance the quantity of half a tooth each vibration, and the
balance or pendulum will be prevented from coming to rest, because the impulse
of the teeth against the pallets will be equal to the resistances from friction, and
the reaction of the air. This escapement not being adapted to such vibrations
as are performed through arcs of a few degrees only, another construction has
been made, which has been in constant use in clocks for this century past,
with a long pendulum beating seconds. Fig. 2, on the next page, a b represents
a vertical wheel, called the swing wheel, having thirty teeth. c. d represents
a pair of pallets connected together, and movable, in conjunction with the
pendulum, on the centre of axis f. One tooth of the wheel in the present
position rests on the inclined surface of the inner part of the pallet c, upon
which its disposition to slide tends to throw the point of the pallet further
from the centre of the wheel, and consequently assists the vibration in that
direction. While the pallet c moves outwards, and the wheel advances, the
point of the pallet d, of course, approaches towards the centre, in the opening
4 T
(.94 ii () ROLOGY.
between the two nearest teeth; and when the
acting tooth of the wheel slips off, or escapes
from the pallet c, another tooth on the opposite
side immediately falls on the exterior inclined face
of d, and by a similar operation tends to push that
pallet from the centre. The returning vibration is
thus assisted by the wheel, while the pallet moves
towards the centre, and receives the succeeding
tooth of the wheel after the escape from the point
of d. In this manner the alteration may be con-
ceived to go on without limit. The celebrated
George Graham improved this escapement very
much, by taking off part of the slope furthest from
the points of the pallets; instead of which part
he formed a circular or cylindrical face, having its
axis in the centre of motion. Pallets of this kind
are seen on the opposite side of the wheel at e
and g, having h for their centre or axis. A tooth
of the wheel is seen resting upon the circular inner O
surface of the pallet g, which is not therefore j
affected by the wheel, excepting so far as its motion,
arising from any other cause, may be affected by the friction of the tooth. If the
vibration of the pendulum be supposed to carry g outwards, the sloped surface will
be brought to the point of the tooth, which will slide along it and urge the pallet
outwards during this sliding action. When the tooth has fallen from the point of
this pallet, an opposite tooth will be received on the circular surface of e, and will
not affect the vibration, excepting when the slope surface of e is carried out so
as to suffer the tooth to slide along it. In the two former escapements, there is
always a certain portion of vibration takes place after the drop which drives
the pallet back, and causes the index also to recede through a small arc: this
has been distinguished by the name of a recoil. The escapement of Graham,
and all such as have no recoil, have been called dead beat escapements, because
the index for seconds falls directly through its arc, and remains motionless on
the line of division till the next vibration. It may be observed, that the main-
taining power in Graham's escapement, may be applied during a small
portion only of the vibration; and that an increase of the maintaining
power tends to enlarge the arc of vibration, but scarcely interferes with
its velocity. In the escapements just described, the escape wheel is in continual
contact with the pallets belonging to the axis of the balance, and the friction
arising from this circumstance may be considered as a principal cause of the
irregularity in the going of watches. If we suppose a regulator to be made so
perfect as to be perfectly isochronal, while vibrating in a free position, that
advantage would be diminished, or lost, as soon as it was placed in connexion
with a train of wheels; and the errors would be more or less, according to the
nature and quantity of friction in the escapement. It would be, therefore,
extremely useful to secure to the regulator a perfect liberty of vibration,
except during the short intervals of time which may be necessary for the action
of the escape wheel, to give it a new impulse. This ingenious idea was first
started, and also carried into execution by P. Leroy, who in 1748 presented to
the Academy of Sciences in Paris a model of a detached escapement, the
effect or action of which may be briefly described as follows: an escape wheel
is kept in repose by a lever detent; the balance unlocks the detent, and
receives an impulse or stroke on a pallet through a part of every second vibra-
tion, and during great part of its course it is free and detached. A great
variety of escapements have been contrived by various ingenious men; those
in which springs are used in the locking pieces instead of pivots are at present
generally preferred; we shall, therefore, proceed to describe the escapement of
Mir. Arnold, who we believe is the author of this improvement. The engraving
on the next page is a representation of this escapement. The teeth of the
escape wheel are of a cycloidal shape, in the face part, which is intended for
•

HOROLOGY. 695
action, the sections of which, with those of the two other sides, form a sort of
mixed triangle, b b d represents the detent, which is formed of a lexible
piece or spring, bending between c and n, and in the part n b d, which is
stronger than the other, is fixed the locking pallet a, opposite an adjusting
screw f. The pallet projecting below the spring detent locks upon the interior
angle of the tooth, suspending the
motion of the escape wheel, and
leaving the balance to vibrate free,
as pointed out in the preceding
escapements. The action of the
spring detent (for the joint of the
detent is itself a spring) presses the
locking pallet against the screw f,
except at the time of unlocking the
wheel. A very delicate spring n e,
called the discharging, or unlocking
spring, (and also the tender spring,)
is attached by one end n to the
spring detent c b n b a ; and passing
under the adjusting screw f, extends
a little beyond the extremity d, by
the detent itself; h h h is a circular
piece attached to the axis of the
balance, and o the discharging pallet.
This pallet when the balance is in motion from e to d presses against the end
of the discharging spring n e ; and carrying it together with the locking spring
b b d disengages the locking piece a out of the internal angle of the tooth,
with which it was in contact; and the escape wheel then communicates a new
power to the balance by its impulse on a pallet m, which is fixed or set in the
aperture of the circular piece. As soon as this is done, the spring detent, or
locking spring, falls back to its position against the adjusting screw fj and the
pallet, by receiving or intercepting the next tooth, stops the motion of the
escape wheel. When the balance returns from d to e, the unlocking pallet acts
again on the extremity of the discharging spring, but this being very delicate,
gives way without disturbing the detent, or locking spring; and the balance,
after suffering a trifling degree of resistance by that contact, continues its free
vibrations. At the next vibration the unlocking takes place, and the action of
the escapement proceeds successively, as explained before. The detached
escapement was applied first to chronometers or time-pieces, but is now also
used for astronomical clocks; and various excellent constructions have been
invented by different artists, amongst which we may mention those of Hardy
and Reid. In 1812, Mr. Prior, jun. was rewarded by the Society of Arts for
the construction of a detached remontoire escapement for clocks, which pos-
sesses considerable merit. The advantages of this escapement consist in the
freedom of its parts from friction; in the exact and equal impulse which it will
continue to give to the pendulum, unaffected by the clogging of , oil and
increased friction of the train; and in the small power required for restoring
the tension of the remontoire spring, which does not require to be wound up
quick, or to be pushed beyond any catch or spring to keep it in its proper
situation. The engravings on page 696, with the following description extracted
from the Transactions of the Society, will explain the construction. The
swing-wheel, Figs. 1 and 3, has thirty teeth cut in its periphery, and is constantly
urged forwards by the maintaining power which is supplied by the small weight;
two spring detents are used to catch the teeth of the wheel alternately; these
are, at the proper intervals, unlocked by the parts marked 1 and 3 upon the
pendulum rod, intercepting two small pins projecting from the detents, as it
vibrates towards the one or the other; the renovating or remontoire spring is
fixed to the same stud as the detents; it is wound up by the highest tooth of
the wheel, as seen in Fig. 1, (its position when unwound being shown by the
dotted lines.) This being the case, suppose a tooth of the wheel is caught by
—l

696 HOROLOGY.
one of the detents, this prevents the wheel from moving any further, and keeps
the renovating spring from escaping off the point of the tooth; in this posi-
tion, the pendulum is quite detached from the wheel; now, if the pendulum be
caused to vibrate to the right, the part of it marked 2 comes against the upper
pin, seen in Fig.2, projecting from the renovating spring, and pushes this spring
from the point of the wheel's tooth; on vibrating a little further, the pendulum
removes the detent which detained the wheel, by the part 3 striking the lower
pin, Fig. 2, which projects from the detent; the maintaining power of the clock
causes the wheel, thus unlocked, to advance until detained by a tooth resting upon
#
º
the end of the other detent on the opposite side; by this means the renovating
spring will be clear of the tooth of the wheel as it returns with the pendulum, and
gives it an impulse with its pin pressing against the part 2 of the pendulum,
until the spring comes to the position shown by the dotted line, in which position
it is unwound, and rests against a pin fixed against a cross bar of the plate ;
the pendulum continues vibrating to the left, nearly to the extent of its vibra-
tion, when the part 1 meets the pin in the same detent, and removes it from
the wheel, and unlocks it; the maintaining power now carries it forward,
pushing the renovating spring before it until another tooth is caught by the
first detent, which detains the wheel in the position first described, the renovating
spring being wound up ready to give another impulse to the pendulum. The
pin is not fixed to the renovating spring itself, but is part of a piece of brass,
which is screwed fast to the renovating spring, and is made very slender near
the screw which fastens it; this permits the renovating spring to give way, if,
by the weight being taken off the clock, or any other accident, the escape
wheel should be wound backwards, so as to catch on the detents improperly.
The weight in the preceding figures merely represents the means by which
the escape wheel was put in motion in the model presented to the Society, which
consisted merely of the escapement; but when attached to a clock, the remon-
toire spring is wound up by the maintaining power of the clock transmitted to
the escape wheel by means of the train.
. Chronometers and clocks for astronomical purposes, in which extraordinary
dicety in the exact measurement of time is necessary, have, besides the com-
pensation pendulums or balances, and detached escapements, before described


HOROLOGY. 697
jewelled pallets, and all their pivot-holes jewelled : they are likewise provided
with a contrivance for continuing their motion during the time of winding up,
when the action of the maintaining power is suspended. For this purpose ‘a
second larger ratchet wheel is added on the same arbor which admits the clock
to be wound up, but with teeth pointing the contrary way; a strong spring, usually
the greatest portion of a circle, connects this large ratchet wheel with the great
wheel of the clock, which is on the same axis with it, one end of this spring
being attached to the great wheel, and the other to the large ratchet; and a
catch proceeds from the inner face of this back plate to the teeth of this ratchet,
which prevents its moving back when the clock is winding up, and serves as a
support for the reaction of the maintaining spring. When the clock is left to
the action of the weight, the small ratchet turns round the larger one, and con-
tracts or coils up the spring till it has strength sufficient to impel the great
wheel and train; and when the action of the weight is suspended, as in wind-
ing up, the spring, freed from the contracting power of the weight, expands
itself and forces round the great wheel, its action in the contrary direction on
the great ratchet being prevented by the catch before mentioned. Leroy is
considered to be the inventor of the spring impeller to prevent loss of time in
winding up, but the idea of continuing the motion of the train during this
time originated with Huygens, for he contrived a method by which the weight
of his clock should continue to act on his train whilst it was drawing up; the
weight in his clock having been made to draw up in a similar manner to that
used in common wooden clocks, instead of being wound up as in our metallic
clocks. -
What has been already advanced, will, we trust, be sufficient to convey a
clear idea of the nature and general construction of horological machines; but
great diversities in their form and a variety of curious movements have been
introduced by the taste and ingenuity of artists in this branch : some of these
excite admiration by the number and intricacy of the component parts, and the
admirable precision with which they act, whilst others evince equal ingenuity
by the simplicity of the means adopted to obtain the end proposed. Of this
last description of clocks, none have as yet exceeded that invented by the cele-
brated Dr. Franklin; it shows the hours, minutes, and seconds, and yet con-
tains but three wheels and two pinions in the whole movement. The lowest
wheel contains 160 teeth, and goes round once in four hours; it carries the
hand on its axle, which points out both the hours and the minutes, as will be
described, and it turns a pallet above it of 10 leaves, on the same axis with
which is a wheel of 120 teeth, that gives motion to a pallet of 8 leaves: the
second-hand is annexed to the same axis with this latter pallet, as also the
swing-wheel, which carries 30 teeth, that gives motion to the pallets of an
anchor escapement, and to its pendulum that vibrates seconds. The dial of this
clock is of singular formation; the external circle on it contains 240 divisions,
numbered from 1 to 60, in four successive notations; this circle shows the
minutes; within it the hours are arranged in three concentric circles, or in a
volute of three revolutions along four radii, which form right angles with each
other. By this arrangement, while the point of the hand shows the minute, its
side exhibits the hour; or, more strictly speaking, shows that the hour is one
of three; but so that it will hardly ever happen that any doubt will remain of
which it may be, as there are four hours difference between the figures next to
each other on the same radial line. A small circle is placed above the great
one, and divided into 60 parts for the seconds. This clock was wound up by a
line going over a pulley and ratchet, on the axis of the great wheel, by which
the weight was drawn up in the same manner as in the common wooden clocks.
Many of these clocks have been made which are found to measure time exceed-
ingly well. The small imperfection in this clock, of its leaving the uncertainty
mentioned as to which of three hours it denotes, though so easily corrected by the
judgment, has given rise to some ingenious contrivances to obviate it. Of these
the most curious is that which forms the subject of the engraving on page 698. To
the great wheel of this clock two concentric plates are annexed, the external
one of which has a groove cut through it along the line of a volute of three
698 HOROLOGY.
revolutions. This groove forms a trough, in which a metal ball is placed, part
of which is seen through the excavation beneath the hour 11 in the figure; as
the plate and groove turn round, the ball rolls along the volute, still approaching
nearer the centre as it proceeds; and when it at last arrives at the centre, it
falls into another trough, by which it is again conveyed to the external part of
the volute. The hours are engraved between the revolutions of the volute,
º w
l º } |
Slſº
|
A
|''
|;
| dº
f
º
* : * - - - - - - - - ~~~ **** -...-----...- --- - - ---~~~~~~-e---> -- r ---re--rr --->er..... . . . ....+:
*Sºrºrº
and the minutes are marked in four divisions of 60 each, upon an external
fixed circle, to which an index annexed to the volute plate points. Several
of these clocks were to be seen in the watchmaker's shops in London some
years ago, but we believe the author of this ingenious contrivance is unknown.
In addition to the parts which measure and register time, and therefore
alone constitute a watch or clock, various appendages are at times connected
with them for pleasure or convenience, as chimes and puppets to clocks,
musical and repeating movements, &c. to watches; but as these are not strictly
comprised under the head of horology, we shall merely notice one or two
inventions of this class, our limits not allowing us to do more.
One very useful addition which is frequently made to clocks and watches, is
the alarum, or contrivance for calling attention at any fixed period of time. An
excellent arrangement of this kind is the patent detached alarum watch, invented
by Mr. Berollas, of the City Road, which is an improvement upon a former
invention of the same gentleman called the warning watch. In the present
invention all the useful parts of the watch are retained, while those that were
inconvenient or had a tendency to disturb its regular movements are here in
a detached state. The advantages that result from this arrangement are, first,





IHOROLOGY. 699
the applicability or adaptation of the invention to all kinds of watches, what-
ever may be the principles of their construction ; second, the alarum being
detached from the watch, it can be made to produce a noise sufficiently loud for
a house alarum; third, alarum watches as before constructed were inconvenient,
from their bulk, to wear—by this contrivance they may be made as flat and
thin as may be desired; and, lastly, the expense is much less than any watches
hitherto made of similar performance. Fig. I represents the mechanism
attached to the watch, by which
the alarum is locked and unlocked,
as it appears when the dial-plate is Fig. 1.
removed. The index by which the
alarum is set to the proper time of
going off, is attached to a hollow
axle fitted upon the arbor of the
ordinary hour-wheel. This index
may be set by hand; but a prefer-
able method is to attach a toothed
wheel 4, which works into an inter-
mediate wheel 7, which works into
the wheel 6, and this latter works
into a wheel 3, fixed at right an-
gles to it upon the square end of
the steel arbor 1, which runs through
the pendant, and has at its other
extremity a milled nut 2, by turning
which nut it is obvious that motion
will be conveyed to the alarum
wheel and index to set it at any
particular hour. To prevent the
train being turned the wrong way,
and to retain the index in its place, a small ratchet wheel is fixed upon the
square part of the steel arbor 1, into which ratchet a spring-pall 5 falls. The
hollow axis of the alarum index is made of steel, and on its underside is formed
into a flat circular plate, as at 44, which represents the
reverse side of the wheel 4; and in this plate a notch is cut sº
straight down on one side, and sloping on the other, as £3 1? º
shown at 45, which is a section of the wheel and hollow § (5) W3
a'
axle, the straight side of the notch lies in the direction of a
radius of the flat plate in 44. The hour-wheel, marked ^.
A, Fig. 2, lies immediately underneath the alarum wheel,
and has on its under side an oblong steel plate, 1, 2, 3,
in the detached figure A of Fig. 2, which is called the
detent. The detent is spring-tempered, has a hole in its
centre for the free passage of the cannon arbor, and is ==TF-
fixed flat upon the hour-wheel by a small screw and steady
* . . & '* g sº 4 º'
pin at 2; into the opposite end of the detent plate at 1,
is rivetted a small pin of sufficient length to pass through
a hole in the hour-wheel, and to project beyond the upper A
surface of the same in such manner, that when the hour- … } º
wheel and the alarum-wheel are put together in their right ... ---ſº
places, and this pin presses upon the flat surface of the steel : 2ſº
plate 44, the end 1 of the detent is depressed below the º
.#
under face of the hour-wheel, but when it comes over the
notch it falls into the same, and allows the end of the
detent to rise and lie flat in the recess in the hour-wheel. The end 1 of the
detent acts upon the circular end 2 of a flat steel spring C, Fig. 1, and shown
detached in the following page ; it is called the elevator, and is fixed in its
place by the screw and steady-pin at Z, which end is thicker than the other
parts of the spring, so that the end 2 is raised above the plate on which it is
fixed ; the degree of elevation may be adjusted by turning the screw-top at ,


700 HOROLOGY.
which works freely through a hole in the elevator. The
end 1 of the detent presses upon the elevator in such
manner, that whilst the detent is depressed it holds
down the end 2 of the elevator; but so soon as the pin
in the detent enters the notch, and the detent rises, the
pressure is withdrawn from the elevator, and it likewise
rises to discharge the alarum, which it does through the
medium of another piece called the propeller, drawn in
its proper place and form at D, Fig. 1, and also shown
in the detached figure in the margin. It is a steel lever
without spring, and turning upon the screw aſ as a ful-
crum; it has a projecting piece. W, which is formed ,--
into an inclined plane, and highly polished and har- JY.
dened; this inclined plane falls directly under the end 2 -
of the elevator C, also polished at this part; consequently,
whenever the elevator is depressed by the detent, its
end 2 will press upon the inclined plane W of the pro-
peller, and drive its end W outwards; this end is formed {(Q.
into a portion of a circle not concentric with a, and
presses against the locker E, Fig. 1, which is a cylin-
drical piece of steel, having in its outer end a small pin s projecting through
the case of the watch; the locker E moves between two pins, and is pressed
against the end of the propeller D by the spring F, and kept at all times in
contact with it. The combined effect of the several parts may be briefly
recapitulated as follows:—whilst the detent is depressed, it presses down the
circular end of the elevator c, which acting upon the inclined plane W of the
propeller D, forces its circular end against the locker E, and causes its small
pin s to protrude beyond the case, in which state it will remain until, by the
revolution of the hour-hand, the pin in the detent falls into the notch on the
alarum arbor; when the elevator rises, and the pressure being withdrawn from
the inclined plane of the propeller, the locker E is pushed in by the spring F,
and remains in that position until the sloping side of the notch 44 has been
moved round sufficiently to depress the detent spring again. The above is all
that is necessary to form the union between the going parts of any watch, and
a detached alarum, because it will be evident that such alarum may be dis-
engaged or set off by the sudden withdrawal of the locker; we shall therefore
proceed to describe the manner in which the alarum movement is operated
upon, whether the alarum of the bell, rattle, or any other kind.
An alarum movement in
its separate state is repre-
sented at G. H., in the an-
nexed figure, and consists of
a frame, the upper plate of
which is nearly half an inch
less than the pillar plate, in
order that the works may be
covered by, and contained
within the bell, as shown at
Fig. 2, which is a section or pro-
file of the alarum movement.
A going barrel, which contains
the mainspring, is placed in -
the centre of the said frame, /
and a steel wheel cut with
ratchet teeth to work the } * *
hammer is fixed on the upper part of the said barrel, its other side, carrying
the main wheel to drive the train, which generally consists of three wheels and
four pinions. The alarum hammer has a spring and a regulating spring on the
opposite side of the plate as shown at K, Fig. 4. The fly pinion has an arm of
steel fixed on its arbor, and as this comes in contact with the projecting pin,
Fig. 2.


HOROLOGY. 701
the works are locked, and the alarum prevented from running down; but so
soon as the pin H is moved, the whole is at liberty, and free to move; the
pin H passes through a hole in the plate, and rises from the locking lever H
on the other side of the plate, as shown in Fig. 4, where it may be seen that this
locking lever turns on a screw pivot at its inner end, and is constantly pressed
to one side by the force of the spring P, which operates in such a direction as to
throw the pin out of contact with the steel arm of the fly arbor, and consequently
always keeps the alarum work in a free state for motion; but it may be locked
at any time by pushing the locking lever H, Fig. 4, back-
wards, or against the action of its spring P; a wire tail, I,
rises perpendicularly out of the outer end of the locking
lever H, and it is this wire tail that is to be engaged with
the small end s of the locker Es, Fig. I, whenever the
alarum is to be wound up and set. This locking lever
H, with its two pins, is here shown in a detached state.
Fig. 5 shows a watch having all the above described
parts appertaining thereto, and placed upon one of the
aforesaid detached alarum movements; I being the case
of the alarum, formed of open-work, chased or otherwise
º
| |||||ITTTIlºſſº
Ujj ||| iTºº -
"||||||Immiſſil
ornamented, and having the appearance, when empty, of the ordinary receptacle
of an external watch case; M being the usual rim that shuts down over the watch
with a spring catch, and thereby holds it steadily in its proper position; the
alarum movement is fixed in this external case, with the pillar plate upwards,
and the works and bell downward; consequently, the wire tail I, Fig. 4, projects
upwards into the case, and in placing the watch within, it is necessary to observe
that the projecting end of the locker s, Fig. 1, comes behind, and engages
with this wire tail, as seen at H F, Fig. 5, in such manner, that it may push
back the locking lever, H, Fig. 4, and thereby lock the train of the alarum
when the rim M is to be shut down, and the alarum hand set as aforesaid


- 4 U.
702 II OROLOGY.
to the time upon the dial, when it is to be discharged. The alarum may
then be wound up by the key, or milled head K, Fig. 2, which is screwed
upon the main spring arbor, ... aºğ
so that it can only turn it Fig. 4. ſº
in one direction without un-
screwing, and the machine
will be ready to operate ; be-
cause at the assigned hour
and minute, the ends of the
locker will be withdrawn into
the watch, thereby releas-
ing the wire tail I, and the
locking lever H, Fig. 4, by
which the alarum will be dis-
charged, and will instantly run
down.
What has been said of
the bell alarum movement,
equally applies to rattle move—
ments, because they consist
of the same parts, and are
constructed and used in the
same manner, except only that the bell, the hammer, and the steel ratchet
wheel for working the same, and the springs connected there with, are dis-
pensed with, and in lieu thereof, the rattle movement, shown in Fig 6, is sub-
stituted. This consists of two strong steel wheels N N, so fixed or screwed
upon the outside of the upper
plate that they may both press
in the same direction against
the two strong pins or studs ºf 7
to receive them, and the upper
plate may in this construction
be made of the same diameter
as the lower plate, because
there is no bell to go over it.
A coarse steel pinion M is fixed
on to a square upon the con-
tinued arbor of the first wheel
in the movement, and which
wheel for this purpose is brought
nearer to the edge of the plate,
in such manner that the lever
of the said pinion may engage
with the ends of both the
springs N N, and by its revo-
lution may carry them some
distance towards r, and on their return they strike against the pins q q, and
produce a powerful rattling noise; more or less springs may of course be used
for a similar purpose, according to the extent of noise required.
Of late years, the ingenuity of watch-makers has been much exercised in
the winding up of watches, without the employment of detached keys; but
from the difficulty of applying such an improvement to watches having fusees,
their efforts have been solely directed to the winding up of those having going-
barrels; and various contrivances have been proposed and adapted to the latter
for that purpose. Mr. Berollas, whose patent detached alarum watch we have
just been describing, has, however, overcome all the obstacles which the sub-
ject opposed to him, and has contrived the means of winding up watches of both
construction without keys, by a contrivance exhibiting great simplicity as well
as ingenuity. For this invention he has taken out a patent, and from the
specification of it we make the ‘ollowing extracts; which, together with the


HOROLOGY. 703
annexed engraved figures, will give the reader a full insight into the arrange-
ment and the mode of constructing this useful improvement. “The first
mover, or power, in most horological works, is obtained either by the action of
a weight or spring. In pocket watches, the power is obtained by a spring
called the main spring, which is enclosed in a box called the barrel. Now there
are two distinct ways of applying the power of this main spring to the first
wheel of a watch; one of them consists in the intervention or agency of a fusee,
which is put upon the first wheel; in the other, the first wheel is put upon the
barrel itself that contains the spring, which arrangement is distinguished from
that having a fusee by the term “going-barrel.” Watches having going-barrels
are wound up by turning round the barrel arbors; and watches having fusees,
by the fusee arbors. My invention consists in a new mechanical arrange-
ment, applicable to the winding up of horological works. First, as respects
what is termed a going-barrel, the following are the contrivances that I have
invented as applicable thereto : Fig. 1 represents a watch with a going-
barrel, to which my invention is applied; in which figure a part of the dial-
plate is represented as broken away, for showing the novel parts, the operation
* Sºs % Fig. 8.
Fig. 7. º h §
o - * º »
| | || º * f.s
of which will be understood by first describing the separate figures, 2, 3, 4, 5.
6, 7, 8, all the same letters of reference in which refer to similar parts. Fig. 2
is the barrel ratchet with its click and spring, which keeps the maintaining
power up ; this ratchet is put on the barrel arbor, which is squared, and the
plate is sunk in which it lays—it is on the side of that part of the plate under
the dial; this barrel ratchet is sunk or turned out as far as the teeth to receive
another ratchet with its click and spring, shown at a, Fig. 3, which I call the
recoiling ratchet. This recoiling ratchet is fastened on to the barrel pulley 6;
the upper side of this barrel pulley is sunk to receive a spring, shown in Figs. 1
and 5, which is the recoiling spring; on the edge of the barrel pulley there is
a groove to receive a chain d, shown at Figs. 1 and 8, which is hooked on a


7() { HOROLOGY.
pin in the said groove. Fig. 7 gives a perspective view of the stud which
keeps the barrel pulley steady and close to the barrel ratchet; the centre of this
stud is round, and the centre of the recoiling spring is hooked on to it; the
other end of the recoiling spring is hooked on the barrel pulley. Figs. 1 and 8
show the impendent, made of the same metal as the case; it turns freely
on a piece of steel g, Fig. 8 ; this steel arbor has a small knob on one side, h,
shown at Figs. 1 and 8, to prevent the impendent from slipping off; on the
other end it is split to receive the end of the chain which is pinned on; the
pendent of the case is perforated, through which the chain passes. I shall
next describe the manner it is to operate, and how it is to be put on the wind-
ing up arbor. When the barrel ratchet before mentioned is put on the square
arbor, the recoiling spring is put on the barrel pulley, and placed over the
barrel ratchet, so as to act on its click; the chain, which is no longer than to
produce one revolution of the pulley, is put through the pendent, and hooked
on to the pulley : the stud is then hooked on to the recoiling spring; by this
stud the recoiling spring is set up one turn, more or less, and the stud is screwed
on the plate. To wind up the watch, the impendent is drawn from the pendent
as far as the chain will permit it; the recoiling spring will bring the impendent
back again to the pendent; and this operation is repeated till the impendent
remains on the pendent, and cannot be more drawn from it, which indicates
that the main spring is wound up. When the works are to be wound up by a
fusee arbor, the ratchet, which keeps the maintaining power, is on the fusee
itself; the fusee arbor, squared, is on the same side of the plate as the going-
barrel under the dial. The recoiling ratchet, Fig. 4, is put on the fusee arbor;
its click and spring are on the barrel pulley, Fig. 6. Here it is to be observed,
that when any works are to be wound up by a fusee, the fusee with the first
wheel and its arbor returns back again, which is not the case with a going-
barrel. h is the relieving click, which has a double action; first, it acts as the
recoiling click, by its action in the ratchet; secondly, it acts as a reliever of the
said click; it is planted on the under side of the barrel pulley, Fig. 6, with its
spring, and must be made in the form shown in the drawing. That part which
is near the edge of the barrel pulley has a small pin, which pin goes through
an aperture of the barrel pulley into the groove where the chain lies. When
the works are wound up, the impendent rests upon the pendent, and the chain
lays round the pulley, which is the same as with the going-barrel. The pin of the
relieving click, which goes into the groove of the barrel pulley, receives a pres-
sure from the chain; it brings the click part out of the ratchet, and gives free
action to the ratchet on the fusee arbor to return back again without any drag
or incumbrance of the click. l, Fig. 1, is the finger touch : it is made of gold,
or some metal which will not rust. By referring to the drawing, it will be seen
that it is a kind of cup with a milled edge, and the minute-hand is fastened to
it: when the hands are to be set, a slight pressure with the end of the fore-
finger is required to turn the hands. In case it is desired to have a watch or
clock wound up in one pull, the multiplying of the turns of the chain round
the barrel pulley will have that effect.
The engraving on the next page exhibits a simple but very ingenious contri-
vance, termed by the inventor, (Mr. Knight, of Birmingham,) the “Patent Duty
Register,” which is designed to operate as a check upon public watchmen, and
to ensure vigilance upon their part, by causing them to register the time at
which they go their rounds, in a manner that will admit of no deception.
Its uses, however, are not limited to this purpose, as it is equally serviceable as
a check upon servants in general, and as a conviction of the correct informa-
tion which it will infallibly afford to employers, it has a tendency to ensure
punctuality on the part of those from whom it may be required. The train of
wheel-work in Mr. Knight's machine being similar to those in ordinary clocks,
the invention must be regarded as an addition or appendage, which is capable
of being applied to clocks already made, as well as to those which are manu-
factured purposely to receive the new combination. The only essential variation
consists in causing the circular dial-plate, which is usually fixed, to revolve, and
the hand or index, which usually revolves, to be fixed. This stationary index
~
HOROLOGY. 705
is placed at the top of the circle, and the hours, as they successively come
under it, denote present time. This index forms part of a bended lever, the
fulcrum of which is in the interior or back of the clock, and the other extremity
of it is attached to a bell wire, with suitable cranks to carry the line of com-
munication to the required place, where a handle is connected to it, for the
individual who is upon duty or guard, to pull at stated times; this operation
raises the power end of the lever, and depresses the index, which makes a
mark upon a temporary scale of hours fixed to the dial-plate, and indicates the
precise time at which each mark was made. As the lever has only one centre
of motion, it follows that the index, which forms a part of it, moves in the
arc of a circle, and consequently would only strike upon a point; but to
enable it to make a line, there is a spring joint where the lever is bent to a
right angle, which allows the extremity of the index to move in a right line

706 HORSE POWER.
*...*
over the plate. The clock face has two concentric circles of hours, the outer
permanent and of a full size, the inner temporary, and of small dimensions.
The latter is an engraved print, the divisions upon which correspond radially
with those on the outer circle, and it is intended that a fresh card should be put
on the dial-plate every day; it is contrived so as to enable them to be put on
with accuracy and expedition ; the card taken off forming a register of the
duty performed, a is the revolving metal dial-plate; b the revolving card; c
an ornamental metal shield, to confine the card down to the plate, which is
fixed to it by means of a thumb screw d, l is the marker, formed of a little
sharp-edged wheel, revolving in a cleft at the extremity of the index, like a spur
rowel, only without teeth; at f is the spring joint of the lever, before mentioned,
forming the upper extremity of the lever. On depressing the lever, the end f
takes the position of e, while c descends on the card dial and makes the mark.
In our drawing, the time expressed is two o'clock; and if the handle be pulled,
the index will descend from the position represented, and make the line drawn
between the II, marked s ; there are two other lines made upon the drawing, also
marked s, which are intended merely as examples to show that such marks were
made at the time expressed by the person on duty. The projection of the
index in front of the dial is exhibited by the projection of its shadow thereon.
HORSE POWER. The force with which a horse acts is compounded of
his weight and muscular strength. If, then, the weight of one horse exceed
that of another to which it is inferior in muscular strength, the weaker and
heavier horse will overcome a resistance which the stronger and lighter horse
cannot, provided the excess of his weight in the smallest degree exceeds his
deficiency in strength. When a horse draws in a mill or machine of any kind,
care should be taken that the horse-walk, or circle in which he moves, be large
enough in diameter, otherwise he can only exert a part of his strength; for, in
a small circle, the tangent in which he draws deviates more from the circle in
which he is obliged to go than in a larger circle. The diameter of the walk for
full-sized horses ought not to be less than forty feet; but if such a space cannot
be obtained, and the circle be reduced, it is advisable to procure horses of
similarly reduced proportions; for it has been found that the same horse loses
two-thirds of his effective strength in being removed from a walk of 40 feet in
diameter to one of only 19 feet. In drawing a carriage, a horse works to the
best advantage when the line of draught inclines a little upwards to his breast,
making a small angle with the horizontal plane. With respect to the quantity
of power a horse of average strength can thus exert, experimentalists have
materially differed, owing probably to the limited extent of their trials, with
horses of different degrees of strength, and under different circumstances; for
much will depend upon the nature of the ground, the proper shoeing, the angle
of draught, the fitting of the collar, &c. As a variation in these points will
fatigue or cramp the full exertion of a horse, a great difference in the amount
of a whole day's work must result; but if we take the average of the data thus
furnished to us by the different authors and experimentalists on the subject, we
shall find it to amount to 160 pounds’ weight, raised at the velocity of 24 miles
per hour, the correctness of which has been most satisfactorily shown by some
experiments on a very extensive scale by Mr. Bevan, that were recently commu-
nicated to the editors of the Philosophical Magazine. Mr. Bevan states, “ In
the period from 1803 to 1809 I had the opportunity of ascertaining correctly
the mean force exerted by good horses in drawing a plough, having had the
superintendance of the experiments on that head at the various ploughing
matches, both at Woburn and Ashridge, under the patronage of the Duke of
Bedford and the Earl of Bridgewater. I find among my memoranda the result
of eight ploughing matches, at which there were seldom fewer than seven teams
as competitors for the various prizes.
lbs.
The first result is from the mean force of each horse in six
teams of two horses each team, upon light sandy soil . . . 156
The second result is from seven teams of two horses each team,
upon loamy ground, near Berkhempstead . . . . . . 15.
HORSE POWER. 707
lbs.
The third result is from six teams, of four horses each team,
with old Hertfordshire ploughs . . . . . . . . . . 127
The fourth result is from seven teams, of four horses each team,
upon strong stony land (improved ploughs) . . . . 167
The fifth result is from seven teams, of four horses each team,
upon strong stony land (old Hertfordshire ploughs) 193
The sixth result is from seven teams, of two horses each team,
upon light loam . . . . . . . . . . . . . . . 177
The seventh result is from five teams, of two horses each team,
upon light sand land . . . . . . . . . . . . . 170
The eighth result is from seven teams, of two horses each team,
upon sandy land . . . 160
The mean force exerted by each horse, from 52 teams or 144 horses, is equal to
163 lbs, each horse; and although the speed was not particularly entered, it
could not be less than at a rate of 23 miles per hour. As these experiments
were fairly made, and by horses of the common breed used by farmers, and
upon ploughs from various counties, the numbers may be considered as a
pretty accurate measure of the force actually exerted by horses at the plough,
and which they are enabled to do without injury for many weeks; but it
should be remembered, that if these horses had been put out of their usual
pace, the result would have been very different. The mean power of the
draught horse, deduced from the above-mentioned formula, exceeds the calcu-
lated power from the highest formula of Mr. Lesslie, and, we may add, that of
Mr. Tredgold. The latter gentleman has, however, furnished us with a most
valuable table, showing the maximum quantity of labour that a horse of average
strength is capable of performing, at different velocities, in drawing boats on
canals, and carriages on railways and turnpike roads.
Useful effect of one horse working one day,
Duration of the in tons, drawn one mile.
& 2 & day's work at *** * =
mºtºiº on, am. || "º" ºf
Miles. Hours: Lbs. | Tons. Tons. Tons.
2} 113 § 520 115 14
3 8 83% 243 92 12
3# 5% 833 153 82 10
4 4; 83 102 72 9
5 2; 83 52 57 7.2
6 2 83 30 48 6.0
7 13. 83% 19 41 5.1
8 l; 83% 12.8 36 4.5
9 0. 83% 9.0 32 4.0
10 0% 83 6.6 28.8 3.6

It will be seen by the foregoing, that the loss of effect is very considerable
upon increasing the velocity of a horse beyond that of 23 miles per hour; this
speed has, indeed, been considered by all writers on the subject, as the fittest
for obtaining the greatest quantity of power from horses, as they can exert it
without being overstrained, throughout a whole day's work. At the highest
speed of 10 miles per hour, which is that of many of our stage-coach horses.
it will be observed that they cannot keep up this pace for more than three
quarters of an hour; that is, 74 miles per day is as much as they can perform
without being soon exhausted. The amount of useful effect assigned by Mr.
Tredgold for this day's work of only three quarters of an hour, is 3.6 tons
drawn one mile, which is equivalent to nearly half a ton drawn 74 miles. Now
the weight of an ordinary stage-coach and its load is about four times the lest
708 HORSE-SHOES.
mentioned quantity, or two tons; consequently we perceive the necessity of
four horses being employed, as is customary, to do the work at that high
velocity which one horse would easily perform at the velocity of 2% miles per
hour. In stating the power of steam engines, it is usual to say the number of
horses' power it exerts, each horse power being estimated as equivalent to
raising 33,000 lbs. one foot high per minute. See the article STEAM.
HORSE-SHOES. Curved pieces of iron, made to fit accurately the horny
hoofs of horses, to which they are nailed in a peculiar manner; the use of the
shoes being to preserve the hoofs from the destructive effect that would take
place by their collision and friction against the hard substances of which our
common roads are formed. It is a common rule to make the shoes three times
as thick at the toes as at the heels, so that by this means the frog (which is a
central projection in the foot) may come down to the ground. The nails are
all placed forward, four on each side, but not approaching too near the heels,
and are countersunk in conical or wedge-shaped holes. For horses which go
in shafts, or are used in hunting, it is usual to make shoes with only one heel,
which should be outward. The horse's heel is rather lowered on that side, and
the inner heel of the shoe somewhat thickened, so as to balance and bear
equally. The best breadth for the shoe of a medium-sized horse is said to be
one inch at the toe, and three quarters at the heel; the weight, about eighteen or
twenty ounces. In order to fit the shoe without causing the horse to stand too
much on his heels, the under part of the crust, or wall of the hoof, is pared
away to receive the excess of thickness in front; for the bottom of the shoe, it is
generally conceived, ought to be perfectly flat, without any stubbings or calk-
ings in front. Paring away the heels is a most destructive practice, except in
case of absolute excrescence in those parts; nor should the bars (or diagonal
ridges) that extend from the heels to the frog, or central projection, ever be cut
more than is absolutely necessary for the purpose of keeping them in a clean
and healthy state. . A good open heel is the indication of a powerful foot;
hence the sides of shoes ought not to be much contracted; when the heels are
tender, what is called a bar-shoe ought to be applied. On the frog the horse
chiefly depends for a spring or resistance at the bottom of the foot : if this part
does not touch the ground, the whole motion will be derived from the upper
parts of the limb, and a very uneasy gait will inevitably follow : this points
out the propriety of leaving it fully at liberty to come in contact with the
ground. Mr. Colman, the distinguished professor of the Veterinary College,
says, that “no animal, nor any part of the animal, can be preserved in health,
where the natural functions are perverted; and he strongly urges the necessity
of some great alterations being made in the practice of shoeing horses, so that a
portion of the weight of the animal may be sustained by the frog, which, from
its central projection in the foot, and the tough elastic nature of its substance,
was evidently designed for that purpose. In a recent paper on the same subject,
from the pen of Mr. Cherry, that gentleman entirely coincides with the author
just quoted, and considers that not only the frog, but the sole also, (which is that
horny portion of the foot between the frog and the exterior wall or crust of the
hoof,) should be made to sustain its proportion of the superincumbent weight;
and, he adds, that any treatment which deprives these parts of pressure, must,
according to true physiological principles, induce disease. It is evident that a
horse in a state of nature presses with the whole surface of his foot upon the
ground, the rim of the hoof, by its angular projection, preventing slipping, and
the frog serving as a cushion to prevent any ill effects from violent concussion.
By the ordinary mode of shoeing, however, the whole weight of the horse is
thrown upon this angular rim, or wall of the hoof, contrary to the designs of
Providence, and the plainest dictates of common sense; for, being shod with a
thick bar of iron on this part, the foot is thereby lifted up, forming a hollow
cavity within the shoe, which, as Mr. Cherry says, “deprives the foot of that
support which it would otherwise receive from the earth, and greatly deranges
the mechanisin of the whole foot.” The same author p oceeds to observe, that
the feet of fan m horses, though usually in that condition termed a state of
neglect, will, upon examination, be found generally “moist, cool, and healthy;
HORSE-SHOEING. 709
while a foot kept clean, is dry, brittle, and full of cracks;” which is evidently
owing to the shoes of the former being usually clogged with earth, by which the
whole surface of the foot is made to sustain the pressure, instead of the mere
rim; the earth likewise contributes to the healthful condition of the feet by a
supply of moisture for absorption. “Perhaps,” Mr. Cherry continues, “it may
be possible to prepare some compressible and adhesive substance to fill up the
cavity after the shoe is on, which shall give support to the whole foot, yet
without impeding the full action of its elastic properties.”
The late Mr. Robert Dickenson entertaining the same views of the subject
as the above-mentioned eminent authorities, took out a patent for some
improvements in horse-shoes, of which the following is a description. In the
annexed engraving, Fig. 1 exhibits a plan, and Fig. 2 a side view of the im-
proved shoe as fitted on to the foot. Fig. 3 represents the ordinary English
Fig. 1. Fig. 2. Fig. 3.
mode of shoeing, which has been here introduced merely by way of contrast.
By Mr. Dickenson's plan, a piece of stout leather is cut to cover the whole
under surface of the hoof; and on this is rivetted a plate of iron of a shape
and magnitude to cover the frog, which it is designed to protect against injury
in travelling upon hard stony roads; under the leather covering is stuffed into
the hollow of the hoof a quantity of sponge, and the shoe being nailed on
through the leather, the whole is thus simply and permanently secured until the
iron shoe is worn out, the leather lasting out several iron shoes, owing to its
compressible elastic nature. The absorbent nature of the sponge keeps the foot
always moist, and the whole surface of it is brought to sustain the pressure. It
will be observed that the iron rim of Mr. Dickenson's shoe is curved after the
French manner, as shown in Fig. 2. From the rapid action of a horse's foot
it is not easy to discover the precise kind of motion which he makes in
stepping out and relieving his foot for the next step; but it is ascertained to be
a rolling from heel to toe. Now the flat shoe represented in Fig. 3, which is
the common English form, evidently presents an obstruction to this particular
action; frequent stumbling from an unnatural effort to overcome the difficulty,
and a straining of the muscles and tendons, to which nature has assigned due
limits, seem to be the unavoidable consequences. On the contrary, the French
shoe is so curved as to conform to the natural figure of the hoof, and consequently
presents no impediment to the natural action of the foot; to this circum-
stance may therefore probably be attributed the well-known superior sure-
footedness of French horses. The impropriety of a perfectly flat shoe is
manifested by the toe part being generally worn down as thin as a sixpence,
while the sides are frequently half an inch thick.
With the view of obviating the presumed necessity of fastening the iron
shoes to herses by nailing them to the hoofs, Mr. William Percival, of
Knightsbridge, took out a patent in 1828 for a mode of securing them to
horses' feet by means of straps or sandals. In the engraving on the following
page, Fig. 1 represents a plan of the shoe, which is of the kind called the frog-
bar shoe; in the front is a tongue a, turning upon a hinge, and having two slits
in it to receive the band or strap, and keep it in its place; at the extremities of
the frog-bar are two double loops or rings, bb, turning upon hinges or holes in
the ends of the bar. Fig. 2 shows the shoe attached to the foot of a horse,
the strap c, of elastic web, is passed through the lowermost of the two rings;
through the lowermost slit in the tongue; through the lowermost ring on the
opposite side; then through the uppermost slit in the tongue; and afterwards

4 x
710 HORSE-SHOEING,
through the buckle on the other end of the strap, and drawn tight. The strap a
is passed through the uppermost of the two rings on one side, and over a pade,
Fig. 1.
placed under the heel of the animal, then through the uppermost rings on the
opposite side, over a pad f. and secured by a buckle on the other end of the strap.
Mr. Benjamin Rotch, the barrister, has distinguished himself by his atten-
tion to this subject, which so intimately concerns not only the welfare, but the
utility of the most interesting and valuable animal in the creation. In 1810 he
had a patent for a flexible elastic horse-shoe; and in 1830 a second patent,
entitled “improved guards or protectors for horses' legs and feet under certain
circumstances;” and as this patent may be regarded as an improvement upon
the former, we shall notice the latest only. These “improved guards are to
be made of caoutchouc, or Indian rubber; when one is to be applied to a horse's
foot, the neck is to be cut from a caoutchouc bottle, which is then to be softened
by immersion in hot water, and drawn over a block made of the shape and size of
the foot for which it is intended. On this block it is permitted to cool, when it will
retain its shape; and by its elasticity it will adhere to the horse's foot when drawn
on to it. On the exterior of this shoe is to be applied a sole of sheet-iron, made
of sufficient size to allow of its edges being cut and turned up round the hoof, to
keep it on the foot; but it is also fastened to the Indian rubber by means of rivets
with very broad and thin heads; and to the sheet-iron sole is to be fastened, if re-
quired, horse-shoes of the usual forms. In the preparation of the guards for the
legs of horses, both the top and the bottom of an Indian rubber bottle are to be
cut off, and after being soaked,
softened, stretched on a block,
formed, and cooled, is to be ap-
plied to such of the legs or knees
of the animalas require protection.
For the purpose of ensuring a
perfect fit to a horse's foot at a
small expense, Mr. Dudley, of
King-street, Soho, took out a ſºft
patent in 1823 for a horse-shoe ſh
of cast-iron, an under side, or ||
ground view of which is repre-
sented in the annexed cut. After
being cast to the precise model
of the foot taken from a plaster
cast, it undergoes that process of
amnealing (now so well under-
stood and practised) by which it
is rendered so soft and malleable
as not to be liable to break by
concussion in travelling over the
roughest pavement. At A A is


HOT-PRESSING. 711
a raised border, or cord, the use of which is to strengthen the inner vein or
web, also to prevent pieces of flint or gravel, &c. from being forced on the sole
of the foot, which frequently happens with the common shoe, as that affords no
such protection. This form is also considered by the patentee to give great
security to the tread of the horse, either over pavement, road, or field. At the
ends B of the shoe, concavities are formed, which become stops, equal in effect
to the rough shoeing, or turning up at the heel, without altering the even
bearing of the horse's feet upon the ground, so essential to his true motions,
and the security of both horse and rider. If proper attention be paid to the
manufacture of these shoes, especially the annealing process, they would prove
of great utility, as they can be quickly made of any size, figure, or pattern,
exactly suited to the feet of any particular horse, and supplied in any quantity,
all precisely alike.
HOSE. A term given to a flexible tube attached to hydraulic engines, for
conveying water or other fluid to any required point. Fire-engine hose was
originally made of leather sewed up, which being very liable to get out of
order, many attempts have been made to discover some cheaper and more
durable material. Flax, or hempen hose, woven without a seam, have long
been employed on the continent; and the Society of Arts, in London, have for
years past been in the habit of offering a reward for its production in this
country. According to Beckmann, however, a manufactory for this article
existed in the neighbourhood of Bethnal-green, towards the end of the eigh-
teenth century, but the speculation did not succeed. One of the London
Insurance Offices a few years since imported a length of the best hempen hose
from the continent, but it did not answer, being found not near so convenient
in use, nor so durable as leather. Mr. Hancock has manufactured some hose
of canvas, with layers of caoutchouc between them, which has been found
useful in many cases where leather would have been ineligible. , Leather hose
was formerly made by sewing with strong twine, and subsequently with copper
wire; neither of these methods, however, was found sufficient to keep the hose
constantly water-tight, and all the best hose now made is not sewn at all, but
rivetted. The fire-engine establishments of London and Edinburgh make their
own hose; the method adopted by them is as follows: the leather, levelled to a
proper thickness, and in lengths of about four feet, is gauged to the breadth
required; holes are punched, four at a time, all down the sides, by means of a
small press. The ends of each piece of leather are cut crosswise, at an angle of
about 370; the different pieces of leather necessary to form a length of hose
(forty feet) are then rivetted together at the ends. The length of leather thus
formed is then placed on a bench, and a long flat iron bar laid upon it; the
rivets are next put into the holes on one side of the leather, and the holes on
the other side brought over them; washers are then placed on the rivets, and
struck down with a hollow punch. The points of the rivets are then hammered
down over the washers; this done, the bar of iron is shifted along, and the
operation continued until the whole length is completed. A piece of rivetted
hose made in this manner has been found capable of resisting a column of
water nearly 500 feet high. The following composition has been found most
efficacious for the preservation of leather hose, viz. one gallon of neat's-foot oil,
two pounds of tallow, and a quarter of a pound of bees'-wax, melted together,
and applied warm, the hose being in a moist state.
HOT-BEDS, in Gardening, are beds made with fresh horse dung, or tanner's
bark, and covered with glasses to defend them from inclement weather.
HOT-HOUSE. A garden erection, similar to a green-house, employed either
for forcing plants, or for the training of exotics, provided with a stove or flue
for the diffusion of artificial heat, and the means of duly regulating it.
HOT-PRESSING is, strictly speaking, the art of applying heat in conjunction
with mechanical pressure; but it is generally understood to mean the employ-
ment of that process to paper, linen, and similar fabrics, by which they acquire
a smooth and glossy surface; and the mode of operating is as follows. A number
of stout cast-iron plates are heated in an oven constructed for the purpose ;
when they have acquired the proper temperature, they are taken out and put
712 HOT-PRESSING.
into a screw-press, in alternate layers, with the goods to be pressed, in the
manner shown in the subjoined engraving; and when paper is the material to
be hot-pressed, in addition to the heated iron plates, a highly-glazed pasteboard
is put alternately between every sheet of paper; the hard polished surfaces of
the pasteboards, in consequence, produce upon the soft and spongy sheets of
paper that smooth and elegant appearance by which hot-pressed paper is
distinguished. The great inconvenience and labour attending the drawing of
the heavy hot iron plates from the oven, then carrying them to, and lifting
them into the proper situations in the press, struck the editor of this work as
susceptible of amendment. With this view of the subject he devised a press
from which the plates never required removal, and wherein they are constantly
kept at the required temperature by hot air from a small furnace beneath. By
this arrangement, fuel, time, labour, and space, may be saved. The press itself,
as shown in the subjoined elevation, does not materially differ from those in
general use. The bed b, and the head-piece c, must be of the most solid and
tenacious materials; these parts are braced and held together by four stout cast-
iron hollow columns or cylinders da, having a longitudinal slot mortice throughout
their length for the reception of the corner pieces of the plates, as shown by the

HYDRATES. - 713
annexed diagram, which exhibits a plan of
a plate, with its four corner pieces inserted
in the slots of the cylindrical columns, the
dark central parts of each being the space
where the hot air acts upon the corners of
the plates; the heat from which, by the
conducting power of the metal, is quickly
communicated throughout. A series of
these plates is shown in the elevation,
attached to each other by means of short pieces of chain, which allow the
plates to be pressed nearly close together, or the drawing of them further apart
by the action of the screw, e. The ends or corner pieces of the plates are
shown by dotted lines, as inserted in the hollow columns. The furnace or
fire-place is placed underneath at f; at g is the ash-pit, and at h is the hot-air
chamber. The bars of the furnace are made hollow, which, being heated by
the burning fuel, the cold air rushes through them, abstracting caloric in its
passage, and is received at the back into the hot-air chamber, which lines the
sides, top, and part of the back of the fire. The air in this chamber derives a
great increase of heat by radiation through the iron partition which separates
it from the fire. The hot-air chamber is of course kept closed, the front plate
being merely removed in the drawing to show its form; a sliding plate should
be made to fit the front ends of the hollow bars, by which the quantity of air
admitted may be lessened or augmented; and by a due attention to the
management of the fire, the heat may easily be regulated with sufficient
exactness for the nature of the operation. The hot-air is conducted from the
chamber h, by means of four iron pipes, and to each of the cylindrical pillars;
two of these are shown by the dotted lines ii. As the hot-air issues from these
pipes it ascends the columns, impinging in its progress upon the ends of the
º: and heating them to the degree required for hot-pressing. For fire-proof
ouses, see the article FIRE.
HOUSE. A building constructed for the purpose of habitation. The recent
improvements made in the construction of the constituent parts of houses,
such as windows, shutters, roofs, chimneys, &c. we have given under-their
respective heads; and as it would be trespassing far beyond the assigned limits
of this work to introduce into it a regular treatise on the subject of house-
building, it is with satisfaction that we can recommend to the attention of the
inquiring reader, Nicholson's Practical Builder, in which the modern practice
of this most important art is clearly developed in all its details.
HOWITZER. A kind of artillery between a cannon and a mortar; being
longer than a mortar and shorter than a cannon, and from that circumstance
adapted to throw either shot or shells; it is usually mounted as a cannon upon
a travelling carriage.
HULK. A large vessel moored and fitted up for the purpose of taking out
or putting in the masts of other ships, and for various other purposes that may be
required in nautical affairs. They are sometimes employed to contain stores,
and sometimes for the secure detention of prisoners.
HUNGARY WATER is made by distilling, in a water bath, two pounds of
fresh-gathered flowers of rosemary, with two quarts of the rectified spirit of wine.
HURDLES. A light fence of open rails, made in convenient detached
pieces, for fixing separately in the ground by stakes or prongs; the hurdles
being afterwards tied together, end to end, constitute a continued fence. Until
recently they were almost wholly made of split oak or other tough wood; but
now, from the low price of iron and the facilities of manufacturing, iron hurdles
are extensively used.
HYACINTH. A sub-species of pyramidal zircon. Colours red, brown,
green, and grey, and more rarely yellow. The darker varieties are deprived of
their colour by heat, a fact of which artists avail themselves to make zircon
resemble diamond. It is esteemed by lapidaries as one of the gems.
HYDRATES. Compounds, in definite proportions, of metallic oxides
with water.

714 HYDRAULICS.
HYDRAULICS is the term applied to that collection of facts, which
describe the phenomena of fluids in motion. In treating of hydrostatics, we
have shown that fluids press in all directions, and that the pressure is as the
depth: hence if a small hole be made in the bottom or side of a vessel, the
velocity with which the water will issue will depend on the pressure above it,
that is on the depth of the hole. If a vessel be kept quite full of water, so
that the height may remain fixed, and holes be made at various depths beneath
the surface, it will be found that the velocity of the issuing fluid will be as
the square root of the depth of the hole. Hence to produce the velocities
1, 2, 3, 4, the corresponding depths must be 1, 4, 9, 16, which are the squares
of the velocities. To produce a double velocity we see a fourfold pressure is
required. To explain this, we must bear in mind that when the velocity is
doubled, a double quantity of fluid must issue, and as this issues with a double
velocity, the power requisite to produce this effect must be four times greater.
In like manner three times the quantity of fluid issuing with three times the
velocity, will require a power mine times greater, and so on. This law, it will
be seen, is coincident with that of bodies falling in free space by the power of
gravity. To produce a double velocity, a fourfold height is required; to
produce a threefold velocity, a ninefold height is required. Thus it appears if
a particle of water were to fall unresisted from the surface of the fluid to the
orifice, it would acquire the same velocity as the issuing water actually exhibits.
If a small tube were attached to the orifice and turned upwards, the water
would ascend to a height equal to its source, were it not for the resistance of
the air, and the friction against the sides of the tube. The absolute velocity of
the fluid cannot be ascertained by calculation alone, and must therefore depend
partly upon experiment. In the annexed cut it will be seen
that the particles of water, on account of the equality of pres-
sure on all sides, will so far interfere with each other's motion,
that the stream will be contracted a little below the orifice.
This contracted part was called by Sir I. Newton, who first
observed it, the vena contracta, or contracted vein; and its
magnitude compared with that of the orifice, was found to be
as one to the square root of two nearly, or as 1000 to 1414.
Now the velocity found by the rule we have before stated is
the velocity at the vena contracta. But as the velocity of fluids in a channel varying
in diameter is inversely as its sectional area, the velocity at the orifice is less than at
the vena contracta in the proportion of 1 to 2, or as before stated, as 1000 to 1414.
Hence it follows, that the velocity at the orifice is that which a body would
acquire in falling through half the altitude of the fluid above the orifice. From
this theorem we may easily calculate the quantity of water that would escape
through a given orifice in any time. Let a cistern or other vessel be six feet
high, and kept full of water, and it be required to ascertain what quantity of
water would run out through a hole a quarter of an inch area, near the bottom,
in ten minutes. By the laws of mechanics we find that the velocity acquired
by a body falling through half the height, viz. three feet, is fourteen feet in a
second; if, then, we multiply the area of the orifice, namely a quarter of an
inch by 14, and then by 600, the number of seconds in ten minutes, we shall
obtain 2100 cubic inches, or seven gallons and a half as the issuing quantity.
The quantity of water that issues through a hole in the bottom of a vessel
may be varied by inserting small tubes in the holes. Thus it was found by
Venturi that when a small tube was applied whose length was equal to twice
the diameter of the hole, it discharged eighty-two quarts of water in one hun-
dred seconds, while the hole without the pipe discharged but sixty-two quarts
in the same time. If the pipe, instead of being level at its top with the bottom
of the vessel, projects some distance within it, it diminishes the discharge to
less than would occur with the simple hole. In the preceding view of the
velocity of discharge we have considered the surface of the water as maintaining
the same level; but in ascertaining the time in which a vessel would empty
itself through a given hole, it must be evident that attention must be given to
the varying depth of the fluid. If the fluid flow with a velocity of sixteen feet

HYDRAULICS. 715
per second, when the vessel is full, it will flow with a velocity of eight only
when the vessel has discharged three-fourths of its contents, that is, when the
height is reduced to a quarter of its original altitude. If it be considered that
the pressure is continually diminishing with the flow of water, it will easily be
conceived that the quantity of water that will flow out will be only one half of
that which would be discharged if the vessel were kept full. In this case the
surface would sink with a gradually retarded motion; and if the sides of the
vessel were marked with a series of numbers representing the hours of the day,
it would form the clepsydra, or water-clock of the ancients, the surface of the
water being the index. The same law applies to the conveyance of water
through valleys in pipes, as we have shown to exist in the issue of water from
holes in the bottoms of vessels. If it were required to convey water across a
valley of considerable depth, the pipe employed must have great strength to
withstand the pressure arising from the height of its source. If a small hole
were made in the pipe the height to which the water would
ascend, would indicate the great pressure existing. In
this way various fountains may be constructed. In
conveying water from a higher to a lower level, when
it is inconvenient to form a channel, the syphon may be
employed. This consists of a bent tube, A, B, C, having a
shorter and a longer leg. The shorter leg is placed in the
water to be removed, and the air being then drawn out
through a tube communicating with the longer leg, or by
means of a stop-cock, the water will rise in the shorter leg
by the pressure of the external air, and going over the bend
of the tube, will run in a continuous stream as long as the level * ..
of the water at A is lower than that at C. In the flowing of water through
holes in the sides of vessels, the same proportions obtain as in the discharge
through holes in the bottom. If A B repre-
sent a vessel kept full of water, and holes
be made in the sides at a b c, the water
will be found to spout to different distances,
and yield different quantities according to
the depth of the orifice. Thus the quantities
of water that would flow from a and c would
be as 1 to 2, because their depth are as 1 to
4; and from any other hole the quantity
would still be as the square root of its depth.
If a semicircle be imagined to stand with
its diameter on one side of the vessel,
and lines be drawn perpendicular to the
diameter, as a d, be, and cf. these lines will show the proportionate distances
to which the fluid will spout. The vena contracta, in this case, being very near
the vessel, the velocity of projection at this point must be considered as the true
velocity; and this is equal to that acquired by a body falling through the whole
height of the fluid above the hole. The curve c C described by the water, is a
parabola, whose vertex is at c : and by a property of the parabola, B C, the
distance to which the fluid spouts from B is equal to twice the square root of
(Bc multiplied by c A) which is equal to twice c f. In a vacuum, therefore,
double the lines a d, e b, e,f, represent the distances to which the fluid would
spout. If the water, instead of flowing through a very small hole, had to flow
through a long slit, the velocity would differ at the top and bottom, and in this
case, the point which may be taken as that of the mean velocity, is two-thirds
of that at the lowest point. In the action of liquids, as in solids, a considerable
quantity of power is constantly consumed in friction; hence the velocity of
water through pipes or jets is considerably diminished, as is also the motion of
rivers, a circumstance which is essentially beneficial to navigation; for otherwise,
the velocity of the water, continually increasing in its fall, would become so
great as to be unmanageable. For further information in this science, con-
sult the articles, PUMPs, WATER-WHEELs, and the various hydraulic machines.


716 HYDRAULIC ENGINES.
HYDRAULIC ENGINES, are all kinds of machines which either
receive motion from the weight or impulse of water, or are employed in raising
it; but the term is sometimes used to denote a machine which in its general con-
struction resembles a steam engine, but the piston of which is impelled by the
pressure of a column or head of water, The annexed figure is a representation
** a statical hydraulic engine erected by Mr. Manwaring, at Messrs. Cook &
|
Ill
H H A - F- Tur
— — i. ſº- 'º- |
| Alsº ſº. ---
I gº | *_nſ
=#######sº ===llºns
t s' "
* .
ſ
F- #TTTTTTTTTT
ſl T T #= W
}*. — *===--------> ====—- .
T_ — H --- T-- P
Co.'s Alum Works, near Whitby. A is the pipe by which the supply of water
is brought from a head 170 feet above the engine; B is a vessel containing air,
the continual elastic pressure of which prevents the blow that would otherwise
be occasioned by the descent of the water; c. is a throttle valve; d d is a
hollow open cylinder, working within an exterior one, and closely applied to
that cylinder, at the parts e ee e, but elsewhere leaving a vacant space between
the two cylinders for the reception of the water; h h are packings, in order to

HYDRA U LIC ENGINE S. 7 17
prevent the escape of the water between the two cylinders; and i ; are adjust-
ing screws, to tighten the packing in proportion as it is worn away; f fare two
passages that lead into the upper and lower ends of the pipe g, in which the
piston w works. When the cylinder d d is in the position represented in the
cut, the communication is open by means of the upper pipe f, for the water to
flow into the pipeg above the piston w; at the same time the passage is open for
the water in the cylinder g, below the piston, to flow out through the lower pipef
and through the lower part of the open cylinder d, into the pipe w, which is some-
what more than 30 feet long, and terminates in a cistern of water. There is there-
fore, above the piston w, a hydrostatic pressure equal to 170feet of water, and below
it a partial vacuum ; the piston consequently descends to the bottom of the pipe
g. By the time that it has arrived in this position the cylinder d will also
have descended so far as to have opened the communication between the
entering water and the lower pipe f, and to have shut off its communication
with the upper pipe f; the hydrostatic pressure is therefore transferred to the
under part of the piston, which consequently rises, while the water above the
piston pours into the top of the cylinder d, and escapes through the pipe a.
The alternate motion of the slide or cylinder d is thus effected. The rod of
the piston pp is attached at its top to one end of the beam; at the other end of
the beam is a rod, terminating below in the crank m ; the oscillating motion on
this crank is transferred, by means of the connecting bar l, to the axis k, on
which is placed the curved tooth or cam n ; the latter is enclosed within the
rectangular frame (or cam box) j, and, being movable in a horizontal position,
is consequently made to perform a backward and forward motion, by the cam
passing first on one and then on the other side of the box. To the outside
of the box are fixed two guide bars, supported on thin bearings oo, the con-
necting rod p at one end to the guide bar, and at the other end to the arm q of
a bent lever, having for its fulcrum the pivot r, the other end of the lever is
forked, and embraces the pipe a , one of these forks s is connected with the
lower end of the upright rod t, and the other fork is connected with a similar
rod. These rods are fastened at top to the two ends of a cross bar, to the middle
of which is fixed the rod u, which works in the stuffing box v, and gives motion
to the slide d. The slide remains stationary nearly half a stroke of the piston,
in order to allow the water to act with its full force; and this is effected by its
being necessary for the cam, after it has moved the box in one direction, to per-
form about a quarter of a revolution before it can act on the opposite side of
the box. The reason for making the passages ff as large as represented, is to
diminish as much as possible the friction of the water, which otherwise would
retard the motion of the piston. Engines upon the principle of the above
have been long known, and some were erected in Cornwall more than sixty years
ago. Some of the earlier attempts to construct hydraulic engines upon the
principle of the steam engine failed, because water, not being elastic, could not
be made to carry the piston onwards a little, so as to close one set of valves,
and open the other. In an engine erected by Mr. Trevethick, about thirty years
ago, a tumbler connected with the valve gear performs the office instead of
the expansive force of the steam at the end of the stroke. This is now, how-
ever, much better effected by the introduction of an air vessel similar to that
shown in Mr. Manwaring's engine, which has besides, the effect of preventing a
concussion at the end of each stroke.
Mr. Seidler has taken out a patent for an engine, which he calls a hydraulic
engine, but which we think should rather be styled a pneumatic engine, as raising
water is merely one of the objects to which he proposes to apply the principle,
which is that of employing compressed air as a medium for transmitting the power
of any prime mover to machinery at a distance, or in situations where the ordi-
nary modes of connexion would be inconvenient or impracticable. The principle
itself is very old, having been employed by Papin as noticed under the word
AIR. The engraving on the next page represents the application of the prin-
ciple to the purpose of raising water from any depth, and through straight or
circuitous passages. a a represents a cylinder, in which a piston, p, works by
means of a steam engine or other power, h g are copper pipes, forming a
4 Y
7 || 8 HYDRAULIC MACHINES.
communication between the cylin-
der a a and the cast iron tank or
vessel k l ; oo is a large delivery
pipe, of copper or other material,
through which the water is conveyed
from the tank, and diseharged; at
r is an air-tight partition, dividing
the tank into two parts, k and l;
and s s are two air-tight partitions,
proceeding from the top nearly to
the bottom of the tank; e is a two-
way cock, for effecting an alternate
communication between a and k,
and between a and l. The other
parts of the machine will be ex-
plained in the following description
of its action. Suppose the piston p
to be raised from its present posi-
tion in the cylinder, the air above
it will be conveyed through the
valve c, and the pipe h into the
vessel k, and force the water cott-
tained therein through the valve ſ,
up the pipe o 0, while air will be
supplied to the cylinder below the
piston through the valve b. When
the piston descends, the air will
pass from the lower to the upper
side of it by the valve d'; this
operation is to be continued tº
all the water is forced out of k,
when the two-way cock e must be
turned to change the communication
through the valve c to the pipes , ,
and the part of the tank l at the
same time; the air which was
forced into k will be permitted to
re-enter the cylinder through the
pipe w, as shown by the dotted lines
in the cock e, so that no air will be
required to enter at the valve b
except at the commencement of
the operation, or when any of the
air is discharged with the water, or
otherwise dissipated. When the
air is liberated from the receptacle
% of the tank, it will be again filled
with water through the valve m, the
valve i being shut by the pressure of
the water in the pipe o o, During
this time, the water in l will be
forced through the valve w; in the
same manner from k, through the
valve i. The cock e to be turned by the hand or by the machinery, after
such a number of strokes of the piston in the cylinder as is sufficient to displace
the water in one division of the tank. For machines for raising water, see
PUMPs and WATER Works.
HYDRAULIC MACHINES. Under this head we propose to notice
various machines which are at times employed in lieu of pumps for raising
Water, or which have been proposed for that purpose. The most simple, as

HYDRAULIC MACHINES. 719
well, perhaps, as the most ancient (next to the bucket and windlass), is the Cochlion
Water Screw of Archimedes. It consists of a cylinder of wood, of about a foot
in diameter, and of any length at pleasure, and on this a leaden pipe of any
bore is wound from the bottom to the top. When the bottom of the cylinder
revolves in the water (by means of a common winch handle at top, and of a pintle
in the centre of its base, which rests in a bore or step for that purpose below,)
the reclined portion, as shown in the following figure, occasions the water to
enter the mouth of the pipe, and as by its gravity it naturally occupies the
lowest part of the pipe, whilst by the revolution of the cylinder the orifice of
the pipe is gradually elevated, and a different portion of the pipe occupies the
lowest position, the water advances progressively along the pipe, always occupy-
ing the lowest portion of the bends or turns of the pipe, until it at length reaches
the top of the cylinder, and is discharged into a vessel. This, however, raises
but a small quantity, although the height may be indefinite; therefore, when this
machine is used, it will be found eligible to cover the whole surface of the
cylinder with a number of pipes laid close together, or, what is a better method,
and is that which is usually adopted, is to wind a number of spiral feathers
round the cylinder, standing out from it at right angles like the square threads
of a screw, and covering these feathers with an exterior case closely fitting
in every part. These machines were formerly in great repute; but, owing
to their liability to become choked with weeds and mud, they are not often
employed at present.
The figure on page 720 represents what is called the horn-drum; it is formed
of a number of segments passing from the circumference of a large flat cylinder
to its centre. This affords an easy mode of raising water. The mouths or
scoops by turns dip into the water, and as they rise cause it to pass up the horn
or segment, until it is discharged into a trough placed under the end of the
axis, which is hollow, and is formed into a number of separate compartments,
each communicating with one of the horns or segments. One disadvantage
of this machine is that it raises water no higher than the axle, and is therefore
only applicable in situations where the water is required to be raised to an
inconsiderable height. This circumstance renders it necessary to construct it of
double the diameter of wheels that discharge their water at their tops. This
machine, however, might be altered to do so likewise, by confining the scoops
to near the periphery of the wheel, and discharging them by means of lateral
valves, to be opened by coming against a contrivance fixed at the top of the .

720 HYDRAULI(X MACHINES.
-------~~
--" .* ...” *~.
2- 22 >
wheel for that purpose. The Persian wheel, represented in the following engrav-
ing, is free from the defect of the last described. In this machine a number
of rectangular buckets a a a a are hung upon strong pins b b b b, fixed in
the side of the rim, the diameter of which must somewhat exceed the
height to which the water is required to be raised. As the wheel turns, the
buckets on the right hand descend into the water, where they are filled,
and return up full on the left hand, until they arrive at the top at k, where
they strike against the end m of the fixed trough m by which they are
overset, and thus discharge the water into the trough, from which it may be
conducted by pipes to wherever it is required; and as each bucket gets over
the trough, it falls again into a perpendicular position, and so goes down empty
until it comes to the water at o, where it is filled as before. On each bucket is a
spring r which, as it passes over the edge of the trough, elevates the end of the
bucket above the level of its mouth so as to discharge the whole of the water
into the trough. These springs are likewise useful in preventing the concussion
of the buckets against the trough. This machine, as well as the horn-drum, is
frequently driven by means of floats attached to the opposite side of the rim. .
The Hungarian machine, so called from its having been employed in drain-
ing a mine in Chemnitz, in Hungary, produces its action by the condensation


HYDRAULIC MACHINES. 721
of a confined portion of air, produced by the descent of a high column of water
contained in a pipe, and therefore acts with a force proportionate to the weight
of such column. Its general form is shown in the annexed cut, by which it will
appear that it is an exceedingly simple and useful machine, admitting of many
modifications and applications; but it can be used only in hilly countries, or situa-
tions where the source of water by which it is to be worked is as much above the
top of the well as the water to be raised is underneath it. In this figure a is
supposed to be a well, or the shaft of a mine, from the bottom of which it is
necessary to raise the water standing at the level b b. c. c is the surface of
the ground at the top of the well or
shaft, at which the discharged water
must have an opportunity of escaping, *
either by running to waste, or being con- d
verted to some useful purpose; and d is
the spring or other elevated source from
whence the supply of water for working
the machine may be obtained. The
machine itself consists of three cisterns,
chests, or reservoirs, two of which at
e and f must be made very strong, and
perfectly air-tight, while the third at d
may be weaker, and open at the top, as
it is merely for collecting and retaining
the spring, rain, or other water for
working the machine. The lowest close
chest or reservoir e must be sunk be-
low the surface b b of the water in the
shaft or well a, but must not come into
contact with its bottom, otherwise the
water would be prevented entering the
chest by the valve g, which opens in-
wards for its admission. An open pipe
h h passes from very near the bottom
of this chest, through its top, in an air-
tight manner, and proceeds upwards in
the shaft as far as the surface of the
ground, where it bends over to deliver
its water, as at h c. Another open pipe
i i, which may be of rather smaller
dimensions than the last, proceeds from
the top of the lower chest e to very
near the top of the second chest f; and
a third pipe, kl, of the same capacity
as the first, proceeds from very near the
bottom of the second close chest, up to
the bottom of the high reservoir d, but
has a cock, or valve at l, by which it can occasionally be shut or opened. A
cock or valve, of large dimensions, is also fixed at m, by which the second
chest f can be emptied of its water, and a smaller cock is fixed higher up, as at
n, for discharging its air. To set the machine in action nothing more is neces-
sary than to shut the cocks l and m, and open the cock n, from whish the
air previously contained in the lower chest will escape, and its place will be
filled up by the water b b, which will pass through the valve g, until the chest
e is completely filled. That done, the air cock n is to be shut, and the water
cock l opened, when a column of water, equal to the full height and pres-
sure of the cistern d, will rush down the pipe k l, and by filling the chest,
will expel its air, which has no other opportunity of escaping but by the open
pipe i i, down which it will pass, and produce a pressure on the surface of the
water in the lower chest equal to the entire height of the column k l ; and the
air thus thrown into the chest e, being in a condensed state, will form the
k

722 HYDRAULIC MACHINES.
water previously in that chest up the pipe h h, from whence it will be dis-
charged at c. The lower chest e will now be filled with air, while the upper
chest f will be occupied by water: therefore the cock l must be shut, and
that at m opened, when the whole of the water from f will be discharged at
c, and will give the air in e an opportunity of returning again into f through
the pipe i i ; and as the air from e escapes, its place will be occupied by
a new charge of water, which will rise through the valve g, and again fill
the lower chest e, and prepare it for a second discharge. All, therefore,
that is necessary to keep the machine in action is to open the cocks l and m
alternately, that is to say, to keep the cock l open as long as any water flows
from the discharging pipe at h c, and as soon as the efflux ceases, to shut the
cock l, and open m to discharge the water from f. and permit the lower chest e
to fill, which will be effected whenever water ceases to flow from m. The cock
m must then be shut, and l opened, and so on alternately, which may easily be
done mechanically, and without superintendence, by using a part of the impelling
water from d, or that which has been discharged from h c, and which may be
employed to turn a small water-wheel, or to fill two small cisterns in which
floats are made to act. Mr. John W. Boswell devised a contrivance for answering
this same purpose, which will be found fully detailed in the second volume of
Dr. Gregory's excellent Treatise on Mechanics, where this simple machine is
described under several forms and modifications. It must not be supposed that
filling the middle vesself with water will discharge the whole of the water out of
e, otherwise disappointment in its effects will ensue; because, although water is
nearly incompressible, air is highly elastic, and the air in e will be compressed into
less than its natural bulk, or will be condensed with a force equivalent to the
pressure of the perpendicular column of water h h, which it has to overcome;
and as atmospheric pressure was shown, when speaking of the pumps under
the second head or division, to be only equal to the support of a column of
water about 33 feet in height, so if we imagine this to be the height of the pipe
h h, that column of water would require one of double atmospheric elasticity
to support it, and hence the air in e will be condensed to half its former volume,
and, therefore, discharge but half the volume of water, although f should be
completely filled, Dr. Gregory further describes a curious phenomenon which
takes place in the working of this machine, and which never fails to create
surprise in the strangers who visit it, and to whom it is usually shown. That
is, when the efflux at he has stopped, if the cock n be opened, the water and
air rush out together with prodigious violence, and the drops of water, are
changed into hail or lumps of ice, issuing with such force as frequently to pierce
a hat if held against them, like pistol bullets. This rapid congelation is a re-
markable instance of the general fact, that air, by suddenly expanding, generates
cold, its capacity for heat being increased.
The Water Ram, or Bélier Hydraulique, as it was called by its inventor,
M. Montgolfier, of Paris, is a highly useful and simple machine, for the purpose
of raising water without the expenditure of any other force than that which is
produced by the momentum or moving force of a part of the water that is to
be raised. The effect of this machine depends entirely upon momentum, or
the new quantity of force that is generated whenever a body is put into motion;
and the effect of this is so great as to give the apparatus the appearance of
acting in defiance of the established laws of hydrostatic equilibrium; for a
moving column of small height is made to overcome and move another column
much higher than itself. The form and construction of the hydraulic ram is shown
in the figure on the next page. Suppose o to represent a reservoir, or the source
of a spring, which is continually overflowing and running to waste by means
of a channel a few feet lower than itself, as at the level line p p. Instead of
permitting the water to flow over the sides of o, let it be conducted to the level
of p p by means of pipes q q connected with the side of the reservoir, and
terminating by an orifice r, in which a conical or other valves is placed, so as to
be capable of effectually closing the pipe when such valve is drawn upwards; t is
an adjustable weight, fixed on the spindle of the valve s, by means of which the
valve is kept down and open; any water, therefore, that is in the cistern o will
HYDRAULIC MACHINES. 723
ſlow down the pipe q q, and escape at the orificer, so long as the valve remains
down; but the instant it is raised and shut, all motion of the water is suspended.
Thus situated the adjustment of the weight t must take place, and by adding
to, or subtracting from it, it must be made just so heavy as to be capable of
sinking or forcing its way downwards against the upward pressure of the water,
the force of which will depend upon the perpendicular distance from the surface
of the water in o, to its point of discharge at r (represented by the dotted line
ov); consequently, if the valve s be raised by the hand or otherwise, all motion
of the water in the pipe q Q will cease, but the instant the valve is released, it
will fall down and permit the water to escape. The water by its motion acquires
momentum and new force, and consequently is no longer equal to the column
o v, to which the valve has been adjusted, but is superior to it, by which it is
enabled to overpower the resistance of the weight t, and it carries the valve up
with it, and closes the orifice r. This is no sooner done than the water is
constrained to become again stationary, by which the momentum is lost, and
the valve and weight again become superior, and fall, thus reopening the orifice,
and permitting the water to flow again; and as the pressure of the water and
the weight of the valve each alternately preponderate, the valve is kept in a
constant state of vibration, or of opening and shutting, without any external aid
whatever. Such is the principle upon which the motion of the water in the
pipe q q is produced; but the motion generated cannot be instantly annihilated;
and it is not only of sufficient power to raise the valve s, but likewise to burst
open the lower end of the pipe Q q, unless a sufficient vent be provided, by
which this accumulated force can escape. Accordingly a second valve u is
placed near the lower end of these pipes, and is made to open upwards into an
air vessel w, with a discharging pipe a, and, consequently, whenever the valve
s is closed, the water which would otherwise have flowed from the orifice r
now opens the valve u and enters the air vessel, until the spring of the con-
tained air overcomes the gradually decreasing force of the momentum, when
the valve u closes, and that at S opens to permit the water to make a second
blow or pulsation, and in this way the action of the machine continues un-
ceasingly, without any external aid, so long as it is supplied with water and
remains in repair. A small running stream is necessary for this machine, as
the water at o should be kept at one constant elevation to ensure the perfection
of its action. A much greater quantity of water likewise escapes at the orificer
between the pulsations than can be raised in the delivery pipe ar, particularly
if it extend to any considerable height, for the comparative quantity of water
discharged through r, and permitted to run to waste at r, must always depend
upon the respective perpendicular heights of the pressing column o v and the
delivered or resisting column w ar, and the rapidity of the pulsations will like-
wise depend upon the same circumstances. Mr. Millington, from whose Epitome
of Natural Philosophy the above description is taken, and who has erected
several of these machines in different parts of England, which gave great satis-

724 HYDRAULIC MACHINES.
faction, in order to show their efficacy gives the following particulars of one,
which, at the time when he wrote, had been in constant use for about two years.
The reservoir o is a basin of about 10 feet square and 2 feet deep, formed
partly in limestone rock, and partly in brickwork, the supply of water being
from a natural spring. The pipe q q is of cast iron, 14 yards long, and 2 inches
in diameter. The piece at the end, containing the air vessel and the valves, is
about fifteen inches long; the valves 1% inch each in diameter, and made of brass;
contents of the air vessel, about 1 gallon. The height from the surface of the water
at o to its point of discharge at r, is 6 feet 4 inches, measured perpendicularly.
The delivery pipe a is of lead, 1 inch in diameter, and proceeds horizontally under
the ground 104 feet, and then rises perpendicularly to the height of 54 feet
3 inches above the discharge valve at r, where it delivers the water into a large
cistern. The water is thus raised 47.11 inches above the surface of the spring
which supplies it, and this by a fall of only 6 feet 4 inches. So circumstanced,
the valve s makes about 50 vibrations, or opens 50 times in a minute, when it
loses about two quarts of water, and injects nearly a quarter of a pint into the
elevated cistern at each pulsation; the water lost being to that which is raised
nearly as 17 to 1. This may appear a small quantity of water, but when it is
recollected that the machine is at work night and day (unless purposely stopped),
and furnishes six quarts of water every minute, this will be found to be a supply
adequate to a very large household establishment. The construction above
described is, however, incomplete, as, owing to the mutual incorporation which
takes place between air and water, the successive quantities of water that are
impelled into the air vessel would soon absorb the whole of the air contained
in it, and it would cease to afford that elasticity which is indispensable to the
working of the machine. This was discovered in France by M. Montgolfier,
who added an improvement to the machine by introducing a very small shifting
valve, opening inwards into the lower part of the air vessel, but kept shut by a
small spring. This is shown in the separate shaded figure above the last
described, and represents an improved form of the air vessel. This valve is
self-acting, and effectually prevents the escape of any air or water from the air
vessel; but when the water is thrown back by the shutting of the valve s, it
produces an instantaneous vacuum at the end of the pipe q, upon which the
shifting valve opens, and admits a sufficient quantity of the external air into
the air vessel to keep it constantly replenished, and by this simple addition the
water ram is rendered continuous in its action.
The cut on page 725 represents a machine for raising water, the invention of
Mr. Rudolph Cabanal, engineer, of Melina-place, Westminster-road. It con-
sists of a series of troughs fixed one above another in a frame-work, and so
inclined in contrary directions that each trough is united at one of its ends with
the trough next below it, and at the other end with the trough next above it.
The lower part of this frame-work forms the segment of a circle, and rests
upon a horizontal plane ; so that with a very slight impulse the whole
machine is put into a rocking motion; the lowest trough is thereby made to dip
at each oscillation into a reservoir of water, which enters the trough through
valves at the bottom; these opening only upwards, the water cannot return. As
the next oscillation raises the end that was before depressed, the water runs
along the trough to the opposite side of the machine, where it is discharged
into the depressed end of the trough above it; from this second trough it is at
the next oscillation thrown into the third trough; then from the third to the
fourth at the following oscillation : in like manner it ascends each trough suc.
cessively by the alternate rocking of the machine, until the water is raised and
discharged at the required height. As the number of troughs, and the height
of the machine, will depend upon the altitude to which it is required to raise
the water, and as three troughs will show the arrangement and the action of
the machine, as well as a greater number, we have, accordingly, reduced our
diagrams to the exhibition of only three; these are shown at a b c, Fig. 1,
attached to the framing ee ee e, with its curved segment d resting upon its
horizontal plane p. It is necessary here to notice that the frame-work is
double, that is, there are the same parts on this side the trough as are shown
HYDRAUI, I C M A CHINES. 725
in Fig. 1 on the opposite side, which will be better understood on reference to
the plan Fig. 2, where one side of the parallelogram marked e (as in Fig. 1),
corresponds with the opposite side marked f. Now it will be evident that when
the lowest end marked l of the trough a is depressed, it will dip into the reser-
voir g, and, by the opening of the valves, receive the water as shown; the
reverse motion of the machine, by which the end m is depresscd, then causes
ſiſ
Fig. 1.
Sºs šš=s
sºlºssºs ºss iss=} A:FE::=== -
RSS sºf:=#= . . . * * * -
º “e º: E: E: E:... -- º:*::::::::
*ś--~r:::::::::É=>s: Eºº
#########ºs===
Z2 ########
====
"& - --- É --- =
F
the water to run along a into b, and, at the next oscillation, from b to c, and so
on into any number of troughs in succession. In the plan, Fig. 2, but two
troughs could be shown ; these are the lowest, all the others being of the same
shape : l l is the depressed end of a, showing its long flap-valves, and that the
water runs from one to the other under the partition that seems to divide them.
The end m being depressed, the water flows in like manner into the double
chamber of b, and from b it is discharged into c, which, being above b, cannot
be shown in this plan. To the ends of each trough an inclined plane or board is
fixed to prevent the water from splashing over it; these are shown at h h under
the troughs a b. Contrivances of this kind are described in most of the old
writers upon hydraulics; and in France, where they are known as the “water-
balance,” several curious constructions have been invented.
A patent was taken by Mr. A. Bernhard for a novel mode of raising water
by the joint action of exhaustion, atmospheric pressure, heat, and condensation,
to a height exceeding fifty feet, with the view of applying the fall from that





- 4 z
726 HYDRAULIC MACHINES.
height as a motive power for impelling machinery. The water to be raised runs
from its level into a cistern contiguous to the foundation of a large boiler; and
from the latter proceeds downwards a curved pipe dipping into the cistern. At
the top of the boiler there is another pipe, which leads shortly into a vertical
pipe, upward of eighty feet in height, which the patentee terms the hot water
ascending pipe. To pieserve the temperature of the fluid in this pipe, the lower-
most portion of it, to the extent of 30 feet, is inclosed in the brick flue of the
furnace chimney; hence it is inclosed in an iron funnel pipe, which forms the
remainder of the flue to the top of the building, which is a pyramidal tower
100 feet high. Near the top of the tower is a refrigeratory, formed by a judi-
cious arrangement of two tiers of pipes placed horizontally in a wooden case;
into these pipes the hot water in the ascending pipe (which here terminates by
branching off from the flue) is discharged. Throughout the refrigeratory box,
and surrounding the pipes, a current of cold air is continually passing; this is
brought from the lowest part of the building through a large tube, and is dis-
charged through another proceeding from the top of the refrigeratory, and
extending to 25 feet above the altitude of the tower, to cause a strong draught.
The effect of this current of air is to cool the hot water distributed in its pipes,
from the lower tier of which it runs out and descends a vertical pipe 36 feet in
length, whose lower extremity is turned up and immersed in a cistern of water
to seal it from the air; this pipe the patentee calls the cold water descending
pipe ; the upper end of it communicates with the exhausting pipe of an air
pump, which is used in the first place to obtain a partial vacuum in the pipes
described, and afterwards to abstract the air disengaged from the hot water,
during the progress of the operation. The reader will now perceive, that when
the exhausting process is nearly completed by the working of the air-pump, the
º of the atmosphere will force the water out of the cistern on the lowest
evel up the curved pipes mentioned, into the boiler, and filling the same, the
water will rise up the vertical (hot water ascending) pipe, proceeding from the
top of the boiler to the height of about 30 feet. This being effected, the
patentee says that if heat be now applied to the boiler, the water will thereb
be made to rise 50 feet higher into the refrigeratory. Here, being distributed
in the small pipes, it is cooled, and descends to the cold water pipe, wherein the
pressure of the column of water being greater than that of the atmosphere, the
water will run out over the cistern, and will continue to do so until the equi-
librium is restored, which it is the object of the patentee to prevent, and thus
obtain a constant power by the fall of the water from the cistern. Having so
far explained the object of the patentee, and the principle upon which he
intends to operate, we shall now describe the apparatus more particularly with
reference to the engraving on the next page, which is merely a diagram of the
apparatus, as complete drawings of it would require several figures. a a represent
the walls of the building; b c de four floors in the same ; f the refrigeratory,
which communicates with the hot water ascending-pipe g; h h is the air-tube,
which receives its supply at i, and after blowing through the refrigeratory,
escapes by the tube j, which extends 25 feet above the tower (but is shown, for
want of room, as broken off); the water in the refrigeratory is prevented from
returning by the intervention of a valve, and after being cooled in passing
through the series of pipes, runs down the pipe k; at l is the air-pump with the
pipe n, which connects it with the top of the pipe k, through the medium of
which the other pipes are exhausted; q is the reservoir which receives the water
upon the natural level by a channel as at r ; the operation of the air-pump
causes the water to rise up the pipe s into the boiler t, thence up the pipe g as
high as the dotted line u, after which, heat being applied to the boiler by the
furnace v, the hot water rises to the refrigeratory. About midway of the pipe
g there is a stuffing-box at one of the junctures to allow of the expansion and
contraction of the metal by changes of temperature. The pipe g is shown as
extending vertically through the brick chimney up to w, thence through the
flue a to the box y; hence it proceeds to the refrigeratory, and the flue-pipe
takes a bend as at r, and proceeds to the top of the building. To prove the
truth of the principle, the patentee erected an apparatus on a considerable scale
HYDRAULICON. 727
in the Kent Road, near. Peckham, but the result was a eomplete failure; and
even had it been practicable, we doubt much whether it wºuld have been an
t (=?
º = . . . . ; 3% º .
Nºftº–l ºffiliº! ...? ...
economical mode of raising water to that height, when we consider the fuel that
must be expended to raise the temperature of the water, and the power required
to work the §§
HYDRAULICON, or WATER ORGAN. A musical instrument acted upon
by water; the invention of which is said to be of higher antiquity than that of
the wind organ.

728 HYDROMETER.
HYDRIODATES. Salts consisting of hydriodic acid, combined in definite
proportions with oxides.
HYDROCHLORIC ACID. A compound of chlorine and hydrogen.
HYDROCYANIC ACID. Prussic acid; which see.
HYDRODYNAMICS treats of the mechanical properties of fluids in general.
It is usually divided into hydrostatics, which explains the pressure and equi-
librium of liquids, such as oil, water, &c.;-Hydraulics, which points out the
laws and effects resulting from the motions of liquids;–and Pneumatics, or the
doctrine of elastic fluids or gases, as steam, air, &c.
HYDROGEN GAS. See CHEMISTRY.
HYDROMETER. An instrument for ascertaining the specific gravities of
different liquids. The most common description of these instruments consists
of a hollow ball, of either metal or glass, capable of floating in any known
liquid, and having two stems, the lower one terminating in a weight, in order
that the instrument may float with the stems upright, and the upper stem
(which is of the same diameter throughout), being graduated, to show the den-
sity of the fluid by the depth to which it sinks; as the heavier fluids will buoy
up the instrument more than such as are lighter. In this way, however, it is
clear that the stem must be of considerable thickness, in order that the instru-
ment may have an extensive range, in which case the smaller differences of den-
sity will not be perceptible. To obviate this imperfection various contrivances
have been resorted to; one of the most common of which is, to construct the
instrument as above described, but with a very slender stem, which is divided
into 100 equal parts; and to provide a number of movable rings, all of equal
weight, any one of which being slipped over the stem, when the instrument
floats in distilled water with zero on the stem at the surface of the water, will
cause it to descend until the top of the scale be at the surface; and the density
is estimated by the number of weights required to bring the lower part of the
scale below the surface, minus the number of divisions of the scale which remain
above the surface. But the method of Fahrenheit is both simpler and more
accurate. The hydrometer of Fahrenheit consists of a hollow ball with a
counterpoise below, and a very slender stem above, terminating in a small dish.
The middle or half length (the stem,) is distinguished by a fine line across, and
the instrument is always immersed up to this line by placing weights in the
little dish above. Then as the part immersed is constantly of the same magni-
tude, and the whole weight of the hydrometer is known, this last weight added
to the weights in the dish will be equal to the weight of fluid displaced; and if
the gravity of water be represented by 1000, and the weight be divided into
thousandth parts of the weight of the instrument when it sinks to the middle
of the stem in distilled water, the number of weights required to sink the
instrument to the mark on the stem when floating in any fluid, added to the
weight of the instrument, or 1000, will represent the specific gravity of the
fluid.
The engraving on the following page represents an instrument for ascertain-
ing specific gravities, invented by Dr. Hare, Professor of Chemistry in the
University of Pennsylvania. This instrument, to which the inventor has given
the name of Litrameter, owes its efficiency to the principle, that when columns
of different liquids are elevated by the same pressure, their heights must be
inversely as their gravities. Two glass tubes, of the size and bore usually
employed in barometers, are made to communicate internally with each other,
and with a gum elastic bag G, by means of a brass tube, and two sockets of
the same metal, into which they are severally inserted. The brass tube termi-
nates in a cock, in which the neck of the bag is tied. Between the cock and
the glass tubes there is a tube at right angles to an opening into that which
connects them. At the lower end of this tube, a small copper rod R enters
through a collar of leather. The tubes are placed vertically in grooves, against
an upright strip of wood, tenonned into a pedestal of the same material.
Parallel to one of the grooves, in which the tubes are situated, a strip of brass
is fastened, and graduated, so that each degree may be equal to # of the
whole height of j. tubes. The brass plate is long enough to admit of about
HYDROMETER.
729
1400. Close to this scale a vernier v is made to slide, so that the divisions of
the scale are susceptible of sub-division into tenths, and the whole height of the
tubes into about 2200 parts or degrees.
On the left side of the tube there is &
another strip of brass, with another §
set of numbers, so situated as to r|.
comprise two degrees of the scale
above mentioned, in one. Agreeably
to this enumeration the height of
the tubes is, by the aid of a corre-
spondent graduation on the vernier,
divided into 1100 parts or degrees.
A small strip of sheet-tim k is let
into a kerf in the wood, supporting
the tubes, in order to indicate the
commencement of the scale ; and
the depth to which the orifices of the
tubes must extend. At distances
from this of 1000 parts and 2000
parts, (commensurate with those of
the scale,) there are two other indices,
TT, to the right hand tube. Let a
= }
@
={
E-
*
Š
§
small vessel containing water be made #E}
to receive the lower end of the tube, by ºil"
the side of which the scale is situated; :-
and a similar vessel of any other -*;
fluid, whose gravity is sought, be TºS fe
made to receive the lower end of the t # E
other tube; so that the end of the s É
one tube may be covered by the i =-
liquid in question, and the end of si –2
the other tube by the water. The j| º,
bag being compressed, a great part s *-
of the contained air is expelled º | S
through the tubes, and rises through ºft © H
the liquid in the tumblers. When j
the bag is allowed to resume its shape, j|
the consequent rarefaction allows º
the liquids to rise into the tubes, §
in obedience to the greater pressure s
of the atmosphere without. If the §
liquid to be assayed be heavier than N J
water (as, for instance, let it be con- *
centrated sulphuric acid,) it should 3.
be raised a little above the first
index, at the distance of 1000 degrees
from the common level of the orifices
of the tubes. The vessels holding
the liquids being then removed, so
that the result may be uninfluenced by
any inequality in the height of the
liquids, the column of acid must be
lowered, until its upper surface co-
incide exactly with the index 1000.
Opposite the upper surface of the
column of water the two first numbers of specific gravity of the acid will
then be found; and, by duly adjusting and inspecting the vernier, the third
figure will be ascertained. The liquids should be at the temperature of
60°. If the liquid under examination be lighter than water, as in the case of
pure alcohol, it must be raised to the upper index. The column of water,
measured by the scale of 1000, will then be found at 800 nearly; which shows
that 1000 parts of alcohol are, in weight, equivalent to 800 parts of water; or, in








730 HYDROSTATICS.
other words, 800 is ascertained to be the specific gravity of the alcohol. The
sliding rod and tube at r, between the cock and the glass tubes, facilitates the
adjustment to the index of the column of liquid in the right hand glass tube.
When the rod is pushed in as far as possible, it causes a small leak, by which
the air enters; and the columns of the liquids, previously raised too high by the
bag, may be allowed to fall, till the liquid which is to be assayed is near the
index; then, by pushing the rod in, they may be gradually lowered, and
adjusted to the proper height, with great accuracy. A rod of this kind,
graduated, might answer the purpose of a vernier. &
Meikles' Syphon Hydrometer, represented in the annexed engraving, it will
be seen, is upon this same principle, but of a much simpler
construction. This instrument consists of a glass tube, open
at both ends, and bent into a kind of double syphon, having
four parallel legs; so that the open ends are pointed in the
same direction, or upwards, as in the annexed engraving. The
manner of usingitis very simple: let one of the ends be stopped
with a finger or cock, and water be poured into the other. The
fluid will only rise a small way into the second leg, because of
the included air : next, stop the other orifice, and open the
one first closed; and having poured into the latter the liquid
whose specific gravity is to be tried, open the top of the water
tube; then the instrument being held upright, the two liquids
will arrange themselves so as to press equally on the included
air. This pressure will be measured by the difference in
the heights of the two columns of either liquids multiplied
by its specific gravity, so that by dividing the difference of
the two columns of water by the difference of those of the
other liquid, we obtain the specific gravity of the latter; that
of water being unity. The difference between the columns
may be measured by applying any scale of small equal parts,
or the glass may be attached to a graduated plate furnished
with verniers, &c. The longer the columns of liquid employed, the more
accurate the process. The expansion of the glass or its capillary action cannot
affect the result, nor is it influenced by the expansion of the scale; the only
correction required will be to reduce the observations to one temperature.
HYDROPHANE. A variety of opal, which has the property of becoming
transparent on immersion in water. It is also called oculus mundi. We must be
careful to immerse them only in pure water, and to withdraw them whenever
they have acquired their full transparency. If we neglect these precautions,
the pores will soon become filled with earthy particles, deposited from the water,
and the hydrophane will cease to exhibit this curious property, and will remain
always more or less opaque.
HYDROSTATICS explains the pressure and equilibrium of liquids, or of
what have been generally termed inelastic fluids. A fluid is a body whose
parts are put into motion among one another by the slightest force, and which
return to their former state as soon as the impressed force is removed. Fluids
have been divided into elastic and inelastic; but recent experiments have
proved that there is no fluid that may not be compressed by a sufficient force,
and that will not return to its former state when the compressing force is with-
drawn. The terms may, however, without much inconvenience, be retained,
as the difference in compressibility is so great, that a sufficient distinction
obtains. Thus the same power that would reduce air to one half of its former
dimensions would effect a compression not exceeding one twenty-thousandth of
its bulk in water. Hydrostatics, then, is concerned with those fluids, the com-
pressibility of which may, for most practical purposes, be considered as inap-
preciable. The laws of this science are generally proved by experiments on
water, as a fluid that is most plentiful, and most easily adapted to the purpose.
The principal and most important propositions with respect to pressure are:-
1. That fluids press equally in all directions. 2. That in fluids of equal density
the pressure is proportional to the perpendicular distance from the surface.
That fluids press equally in all directions is seen in a variety of cases, and may

HY 1) ROSTATICS. 731
therefore be easily made evident. . If a cylindrical tin vessel have two holes of
equal size, one in the bottom and the other in the side as near the bottom as
may be, it will be found that each of these holes will permit the contents of
the vessel to run out in equal times. Now as the velocity of the running water
is dependent upon the pressure, it is manifest that the pressure upon the side,
or lateral pressure, is equal to that on the bottom, or downward pressure. That
the upward pressure is also equal is inferred from the fact, that water poured
into one of the legs of a bent tube will rise to an equal height in the other leg.
This upward pressure is a feature that distinguishes fluids from solids, and is
due to the extreme mobility of its particles, owing to the repulsive energy
which is exerted when the least compressing force is applied. We have next
to show that the pressure upon any particle in a fluid is proportional to its
perpendicular depth. In the annexed diagram, if a be
a particle of water, the pressure exercised upon it will
be proportional to the depth Ba: ; for if a hole were
made at a, the fluid (making allowance for the resist-
ance of the air) would spout up to A. e. In like manner
the pressure at C is equal to the perpendicular depth
B C ; and as every particle on the bottom is at an equal
depth, the whole pressure will be equal to that pro-
duced by a column filling the whole space B C D e.
From this it appears that the pressure on the bottom
of a vessel is equal to the area of the base multiplied by
its perpendicular height. In vessels having equal bases the pressure will be
proportional to the height, and in vessels of equal depths the pressure will be
as the area of their bases, and this without any regard to the quantity of fluid
employed. This has given rise to the hydrostatic paradox—“that any given
quantity of water, however small, may be made to balance any other quantity,
however large.” Also the hydrostatic bellows depend on the same principle.
In the cut, A and B are two circular boards connected by leather after the
manner of a pair of bellows, so as to be water-tight. A tube, C D, is made to
communicate with the interior. If a small quantity
of water be now poured in so as to separate the
boards, and a number of heavy weights be placed upon
the upper board, the water in the tube C D will be c
seen to rise till it balance the weights placed upon A.
If the quantity of water in the tube, above the level
A g, be noticed, it will be found to be so much less
than the weights upon A, as the area of the bore of
the tube falls short of the area of the board A. To
make the subject more evident, let us suppose the
sectional area of the tube C D to be half a square
inch, and that of the lower board of the bellows to be
one square foot, or 288 times greater ; it will then
be found that one pound of water in the tube CD
will support a weight of 288 pounds on the board # s—2%
A g. Hn a similar way, a long narrow tube may be j. s=3
inserted perpendicularly into a cask or other vessel; tº T}
after the vessel has been filled, a few ounces of water
poured into the tube will burst it. If a fissure in a rock should communicate
with an internal cavity of considerable magnitude, situated at some depth
below the top of the fissure, and filled with water, the pressure may be so
enormous as to burst the rock. The same effect may be produced by rain
falling into, and filling a long slender chink that may have been left in the
walls of a building; whether the chink is of equal diameter throughout, or
vary in its size, and whether it be straight or crooked, provided it be water-
tight, so as to get full of rain, the effect will be the same, the pressure being
always proportionate to the perpendicular height. This principle has been inge-
niously applied by the late Mr. Bramah, in what is termed the Hydrostatic
Press, a machine by which an almost incredible force may be clºtained in a
•y : A A.
C
º
º












732 HYDROSTATICS.
very small compass. (See Bramah's Press). From the equal pressure in all
directions arises the tendency in fluids to find their own level, so that the surface
of every fluid at rest is horizontal; and for a similar reason, if two fluids be in
the same vessel, and do not mix, their common surface will be parallel to the
horizon. From what has been stated on the nature of fluid pressure, it will be
easy to calculate the pressure on any horizontal surface. Thus, if a cubical
vessel be filled with water, the pressure on the base will be equal to the weight
of the fluid. The same pressure will obtain if the vessel be of a conical form,
provided the area of the base and the height be the same. The pressure upon
a perpendicular surface will of course vary with the depth. If a board one
foot square be placed perpendicularly in a vessel of water, and be divided into
horizontal sections, each one inch deep, then calling the pressure at the depth
of one inch 1, the pressure at two inches will be 2, at three inches 3, and so on;
hence the whole pressure will be equal to the sum of the series 0, 1, 2, 3, 4, 5, 6,
7, 8, 9, 10, 11, 12: this will amount to half the pressure which would have
occurred if the board had been situated horizontally 12 inches below the
surface. Now, as the centre of gravity of this surface is situated in the
middle of the board, it follows that the area of the board, multiplied by
the distance of its centre of gravity beneath the surface, will be equal to
the pressure. From a more extended investigation it is found that this rule
is general, that the pressure of a fluid against any surface, in a direction per-
pendicular to it, varies as the area of the surface multiplied into the depth
of its centre of gravity. From this we see that the pressure against the four
sides and bottom of a cubical vessel is equal to three times the weight of
the contained fluid. From this also may be calculated the pressure on dock
gates, on the lower parts of ships, and large cisterns, coolers, &c. In all
cases of pressure the amount, as determined above, must be multiplied by the
specific gravity of the fluid employed, as it will be evident, that if two vessels
of equal sizes and similar shapes be filled, one with water, and the other with
mercury, that the pressure on the base of the latter will be so much greater
than that on the former, as the weight of the mercury exceeds that of the water.
The equal pressure in all directions causes the surface of all large bodies of
water to be horizontal, and also the surfaces of any two bodies of water com-
municating by a tube or otherwise; hence the construction of water levels. In
the annexed cut A B is a tube turned up at each end,
and filled with mercury or water. Upon the surface
of the fluid at c and d are small floats, carrying an
upright sight, with a horizontal wire or hair across it.
When the instrument is held in the hand, on looking
through c its cross wire will cover that of d, because - -
the fluid stands equally high in both legs. If it be * P;
required to know whether any distant object be horizontal, it is only necessary
to point the instrument toward it; and if the two cross wires and the object
coincide, the object is in the same horizontal line. The common spirit level
consists of a small tube filled with spirits of wine, except a small space, which
contains a bubble of air. The tube is hermetically sealed; and when placed
on a horizontal surface, the bubble will be seen in the middle of the tube.
A little reflection on the nature of hydrostatic pressure will show its appli-
cability to the purpose of ascertaining the comparative weights of bodies, or,
what is commonly termed their specific gravities. If a body of any shape,
either as heavy as water, or heavier than it, be plunged into a vessel filled with
that liquid, it will of course displace a quantity of fluid equal to its own bulk,
and if the quantity be measured, we have a ready measurement of the mag-
nitude of the solid body that was immersed; for as the water displaced is
equal in bulk to the size of the irregular solid, a measurement of the one will
serve to ascertain the other. Again, if the quantity displaced be weighed,
and the immersed solid weighed also, we shall have the relative weights of the
two substances, or their specific gravities. If the whole of the water displaced
could be accurately collected and weighed, this method would furnish a ready
mode of ascertaining the relative weights of any two bodies, Thus, if two

HY GROMETER. 733
bodies of equal weight, successively plunged into water, were to displace one
and two ounces of water respectively, the relative weights of the bodies would
be as 2 to 1. As, however, considerable difficulty would arise in the use of
this method, the following process is used with bodies heavier than water.
Weigh the body in air, and also in water, observe how much of its weight it
loses by immersion in the water, and then divide the weight of the body in
air by the loss in water. Suppose a piece of gold to weigh 58 grains, by
weighing it immersed in water it would lose 3 grains of its weight; divide the
58 grains by 3, and it will give 194 as the specific gravity of gold; that is,
the gold would be 193 times heavier than an equal bulk of water. The weights
of solid and liquid bodies are usually compared with that of water, one cubic
foot of which contains just 1000 ounces avoirdupoise. Hence, by referring to tables
of specific gravities, we obtain the real as well as the relative weights of bodies.
Thus, in the example we have given, a cubic foot of gold would weigh 1000 × 194
= 19,333 ounces. If the solid consist of a substance that is soluble in water, it
must be covered with a coating of wax or varnish, and an allowance made for
the difference produced by the coating. When the solid consists of several small
pieces, a cup must be previously immersed in the water, and accurately coun-
terpoised; the fragments may then be placed in it, and the loss of weight ascer-
tained. . If the body whose specific gravity is required be lighter than water,
anotherheavier body must be attached to it, and the loss of weight in the compound
being noticed, the loss in the heavier body must be subtracted from it, and it
will give the loss of weight in the body under investigation. The specific
gravity of liquids is found by filling a small bottle (which holds a definite
quantity, say 1000 grains of water,) with the liquid under examination, and
then weighing the quantity contained, the proportion which this bears to 1000
is the specific gravity of the liquid. Thus, if the bottle be successively filled
with water, real alcohol, and nitric ether, the weight of the equal measures
would be 1000, 797, and 908, which represent the specific gravities of these
fluids. This experiment shows clearly the nature of specific gravity, which it
will be seen is simply obtaining the real weights of equal measures of different
substances. If we could obtain a cylinder or cube of copper, and another of
gold, of exactly the same dimensions, and compare their true weights with the
weight of a portion of water of the same magnitude, we should at once obtain
their relative or specific gravities; but as it is inconvenient to alter the shapes
of bodies, and, in many cases, would be next to impossible to obtain them of
precisely the same dimensions, the usual mode of weighing in water, by which
we obtain the weight of a quantity of water of equal bulk with the solid, is
infinitely preferable. For further information on the subject of this article see
BRAMAH's PREss, HYDROMETER, SPECIFIC GRAVITY, &c.
HYDROSULPHURETS. Compounds of sulphuretted hydrogen with the
salifiable bases.
HYDRURETS, compounds of hydrogen with metals.
HYGROMETER. An instrument for ascertaining the degrees of dryness
or moisture of the atmosphere; therefore whatever substance expands by mois-
ture or contracts by dryness, may be employed for the purpose, in connexion
with a suitable index and scale, showing the changes it undergoes. The
hygrometer invented by Saussure consisted of a hair, divested of its oil by
boiling it in water containing one per cent. of sulphate of soda. One of the
ends of the hair was attached to a fixed point, and the other to the circum-
ference of a movable cylinder, that carries a light index; the hair being kept
straight by a counterweight of three grains, suspended by a fine silk thread to
the cylinder, and wound thereon the contrary way of the hair. As the hair
lengthens or shortens by changes in the humidity of the air, the cylinder
is put in motion, and the index fixed thereto points out on a graduated circle
the degree. This pretty little contrivance of Saussure's was regarded as a
faithful indicator of the true condition of the atmosphere until M. de Luc
proved that hair was incapable of becoming a correct measurer of humidity,
and that this was owing to its organic reticular structure. The last men-
tioned philosopher made an hygrometer, in which ivory was employed as the
5 A
73.4 ICE.
medium of exhibiting the change of humidity. As ivory expands by moisture
and contracts by dryness, he formed a very thin hollow cylinder of this sub-
stance, open only at the upper end, into which he fitted the open end of a
very fine long glass tube, like that of a thermometer. Into these he introduced
a quantity of quicksilver, filling the ivory cylinder, and a part of the glass tube.
The consequence is this; when moisture swells the ivory cylinder, its capacity
incrgases, and the mercury sinks in the glass tube; and vice versä, when the air
is drier, the ivory contracts, and forces the mercury higher up the glass tube. As
this instrumentis susceptible of being influenced by heat and cold, like the ther-
mometer, as well as by that of humidity, its indications are not to be depended
upon. Hygrometers are constructed, in a great variety of ways, by means of
sponge, and a rod suspended like a scale-beam. The rod is to have one of its
ends pointed, to serve as an index, and at the other end a hook to which the
sponge is fastened. The sponge is prepared by first washing it thoroughly in
clean water, and when it is dry washing it again in either water or vinegar, in
which a quantity of salt of tartar or sal-ammoniac has been dissolved; after
which, the sponge being well dried, is fit for use. Then having fixed against
that part of a wall over which the point of the index will traverse, a graduated
circular arc, the index will show on this scale the state of the atmosphere; for
when the air is humid, the sponge will imbibe moisture from it, become heavier,
and consequently pull that arm to which it is suspended downwards; while the
other arm or index will move upwards, along the graduated are on the wall. On
the contrary, when the air becomes drier, it imbibes the moisture from the sponge,
which consequently becoming lighter, the index preponderates, and moves
down the graduated arc, thus showing the moisture or dryness of the atmo-
sphere. Instead of the sponge, Mr. Gould recommends oil of vitriol, which
grows sensibly heavier or lighter, as the moisture of the air increases or
decreases; so that being saturated in the dampest weather, it retains, loses, or
resumes its acquired weight, with the continuation, decrease, or increase of the
moisture in the air. So great is the alteration in the weight of this liquor from
the above cause, that in the space of fifty-seven days, it has been known to
change its weight from three to nine drams, and has shifted the tongue of a
balance thirty degrees. The curious on the subject of hygrometers may meet
with a great multiplicity of them in the Philosophical Transactions, and the
various scientific journals.
HYOSCIAMA. A new vegetable alkali, extracted by Dr. Brande from the
hyoscyamus nigra, or henbane. It is a strong poison. The vapour is extremely
prejudicial to the eyes; the smallest morsel of the alkali upon the tongue is
dangerous. Nevertheless preparations of it are very advantageous, given in
medicine, by eminent practitioners.
HYPER BOLA, is one of the conic sections, formed by the intersection of a
plane and cone, when the plane makes a greater angle with the base of the
come than that formed by the base and side of the cone.
HYPOTHENUSE, the longest side of a right-angled triangle.
I.
ICE. Water in a solid, crystallized state, owing to the abstraction of its com-
bined heat. Its specific gravity, according to Dr. Thomson, is .92. The force
of expansion exerted by water in the act of freezing has been found irresistible
in all mechanical experiments to prevent it. Advantage of this wonderful
phenomenon is taken to burst bomb shells, and other massive vessels, by fillin
them with water, plugging them up, and then exposing them to the frost. The
effects of this expansive force are often observable by the bursting of trees, and
the rending of rocks, attended with a noise resembling the explosion of confined
gunpowder. Water after being long kept boiling, affords an ice more solid,
and with fewer air bubbles, than that which is formed from unboiled water; also
pure water, kept for a long time in vacuo, and afterwards frozen there, freezes
much sooner than common water exposed to the same degree of cold in the
open atmosphere ; and the ice formed of water thus divested of its air, is much
ICE-HOUSE. 7.35
more hard, solid, heavy, and transparent, than common ice. Ice after it is
formed, continues to expand by decrease of temperature; to which fact is pro-
bably attributable the occasional splitting and breaking up of the ice of ponds
during the time of freezing, and sometimes, independent of other causes, the
separation of icebergs from the great frozen continent at the poles. According
to Dr. Black, ice requires 147 degrees of heat to reduce it to a fluid.
ICE-BOATS. There are two descriptions of boats which come under this
denomination; namely, those that are designed to sail upon the surface of the
ice, and those that are employed to open the navigation of frozen rivers or canals,
by breaking up the ice. The first-mentioned kind of boats is much used in
Holland, on the river Maeze and the lake Y. These ice-boats are propelled, it
is said, with incredible swiftness, sometimes so quick as to render respiration
difficult; they are found very useful in conveying goods and passengers over
lakes and great rivers in that country. . For this purpose a boat is fixed trans-
versely over a thick plank, or three-inch deal, under which, at the extremities,
are fixed irons, turned up forwards, resembling and operating as skates; upon
this board the boat rests, with its keel at right angles to it; and the extremities
of the boards serve as out-riggers to prevent the boat from upsetting, whence,
therefore, ropes are fastened that lead to the head of the masts, in the nature of
shrouds, and others passed through a block across the bowsprit. The rudder is
made somewhat like a hatchet, with the edge placed downwards, which, being
pressed down, cuts the ice, and serves all the purposes of a rudder in the water,
by enabling the helmsman to steer, tack, &c.
The other kind of ice-boat alluded to, is a strong and heavy-laden canal-
boat, fitted up for the purpose of breaking the ice, by arming the fore-part of
the keel and the bows with iron, which penetrate and break down the ice as the
boat is drawn forcibly along by an adequate number of horses towing it on the
path. This measure of opening the navigation of a canal is seldom adopted,
except when the ice is only a few inches in thickness, or when a thaw has ren-
dered thicker ice of little tenacity.
ICE-CREAM. A species of confectionary made by immersing cream,
variously flavoured, in a mass of ice, contained in a pail constructed for the
purpose, wherein the cream is congealed.
ICE-HOUSE. A repository for ice during the summer season. In London and
other places, ice is kept by the confectioners in deep cellars, from which the ex-
ternal air is excluded as much as possible, and provided with drains to keep them
dry. When the surrounding soil is moist, a frame-work, or case of carpentry is
constructed, having a grating at bottom, and is so placed in the cellar as to be two
or more feet distant from the floor, sides, and roof of the cellar. In this the ice
is said to be as perfectly preserved as in a dry cellar. Some market-gardeners
preserve ice in great heaps, by merely building it upon an elevated base in the
open garden, and covering it over and around by a very thick stratum of straw
or reeds. This plan of preserving ice is in accordance with Mr. Cobbett's
recommendation in his Cottage Economy, wherein he observes that “an ice-
house should not be underground, nor shaded by trees, but be exposed to the
sun and air;” that its bed should be three feet above the level of the ground,
and composed of something that will admit of the drippings flowing instantly
off; and he adds, that “with some poles and straw, a Virginian will construct
an ice-house for ten dollars, worth a dozen of those which cost the man of taste
in England as many scores of pounds.” The ice-houses built by the Virginians
consist of an inner shed, surrounded by an outer one, and having a sufficient
vacant space between the two to enable a person to walk round; the walls and
roofs of both the sheds are made of thatch, laid on about a foot thick; and the
ice is deposited in the inner shed on a bed of straw. In England and France,
the common form of ice-houses is that of an inverted cone, or rather of an
hen's egg, with the broad end uppermost. The situation of an ice-house should
be dry, as moisture has a tendency to dissolve the ice ; it should also be so
elevated that water may freely run off. It should be exposed to the sun and
air (as observed by Mr. Cobbett), not under the drip, or in the shade of trees,
in order that the external deposit of moisture may be readily evaporated. The
736 ICE-HOUSE.
form of the building may be varied according to circumstanº; but in the well
or receptacle for the ice, it is desirable to have sufficient room for the deposit of
two or three years' consumption, as a provision against mild winters. Where
the situation is of a dry, chalky, gravelly, or sandy kinº, the pit may be entirely
below the surface of the ground; in which case, an ice-house on the plan recom-
mended by the late Mr. David Gordon (which was considered by that gentleman
as an improvement upon the American and Italian methods) may be advan-
tageously introduced, of which the annexed sketch represents an elevation.
Dig a pit of about 12 feet deep, -
and wide enough to permit the erec- N
tion therein of a frame of rough wood -*--
posts. This frame is to be 14 feet
wide each way at the bottom, and 16
feet each way at the top, conformably
to the sketch. The posts may be
about 9 inches in diameter, placed
near enough to each other for thin
laths to be nailed upon them, and the
inside be dressed to an acute angle,
so that as little wood as possible may
touch the ice. On the inside let thin
laths be nailed at about two feet
apart. On the outside, at moderate
distances, nail rough boards, and fill
the place within with wheat, or rye
straw set on end. The inside of the
roof to be made in the same way,
and also the gables. Straw is to be
sewed on the inside, and heath or -
straw on the outside of the door. 30 O
The outside of the roof is to be ~ ºf
thickly thatched with straw or heath;
and heath, brushwood, or fir tops, to be filled in between the outside boarding
and the surrounding ground, and then neatly thatched or turfed over. The
bottom of the house, for two feet deep, should be laid with large logs or stones,
next with heath, fir-tops, or brushwood, and then with straw. The ice-house
thus completed, will look like a square bee-hive inverted, and is then ready to
receive the ice or snow. But unless the house be in a very shady place, Mr.
Gordon observes, it may be necessary to extend the roof, where the door is
placed, five or six feet, making a second gable and door, finished in the same
way as the first, and fill up the intervening space, except a passage, with heath
Or Straw.
Mode of filling the house.—When the ice (or snow, if ice cannot be procured,)
is put into the house, it must be well beaten down with a pavior's rammer, or
mallet, and the surface always kept concave, as by this means any snow or ice
that may melt will run to the middle, or interstices, and freeze. For the same
reason, the ice ought always to be kept concave when it is taken out for use.
Should the frost be very intense when the ice-house is getting filled, it may
be very beneficial at the close of each day's filling to throw in thirty or forty
pails of water, which will fill the interstices and freeze. When the house is
full, spread upon the concave surface a carpet, or sail split up the middle, and
upon the top thereof a foot thick of water. When ice is required for the use
of the family, or when it is necessary to put in fresh meat to lie on the face of
the ice for preservation, or to take out for use, the straw and carpet, or sail, is
to be opened in the middle. Should rats infest the place, an iron-wire frame or
case may be required to put the meat or fish, &c. into when lying on the ice.
A small open surface-drain ought to be dug round the house, to prevent any
Water running into it. Opening the door of the house does little harm.

d amp or dense substances touching the ice is much more prejudicial than
ry air.
* * * * wº- * * *- - - -
ICE-SAWS. 737
ICE-SAWS. Large saws used for cutting through the ice for relieving ships
when frozen up. The vessels employed in the Greenland fisheries, and others
that navigate the polar seas, are regularly furnished with these machines, as
the lives of the crew not unfrequently depend on the expedition with which a
passage can be cut, so as to disengage the vessel before the further accumu-
lation of ice renders it an impossible undertaking. The saw, with a weight
suspended to it, is introduced by means of a hole broken through the ice, and
is suspended by a rope passed over a pulley fixed to a triangle. A party of a
dozen or more men, run out and back again with a rope, and thus move the
saw up and down till it has cut its way so far as to hang perpendicularly from
the pulley. The triangle is then moved a foot or two farther, and the sawing
recommences, the services of the whole crew being required in this laborious
undertaking.
Lieut. W. J. Hood, of the Hyperion, R.N. has recently greatly improved
this apparatus; for the communication of which and the presentation of an
illustrative model to the Society of Arts, that gentleman was awarded the
Society's honorary medal. In Mr. Hood's machine, the saw is suspended by
a slight sledge, and is worked by the power of only two or three men at the
end of a lever; a bar, called a propeller, is fixed on the lever between the ful-
crum and the saw, the other end resting on the surface of the ice, and so
adjusted that each motion of the lever shall produce a cut of a given length,
and at the same time, by means of the propeller, push the sledge on, so that the
teeth of the saw shall always be in contact with the ice. The annexed figure
gives a side elevation of the machine. a a a is a sledge, of open frame-work, rest-
ing on the surface of the ice; b a transverse bar passing through the lever c c,
and forming the fulcrum on which it moves; this lever has a cross handle, as

738 IMPULSE.
represented in perspective in dotted lines; e a clamp or brace consisting of two
cheeks, one on each side of the lever, loosely pinned at top to the lever, and
at bottom to the saw f; g a clamp similar to e, by which the weight d (which is
of the shape of a double convex lens) is hung to the lower end of the saw ; ;
the propeller, an iron bar, terminating below in two claws, and at top in a fork,
and suspended on the lever by means of a transverse pin k; l a weight hung to
the propeller at m ; n a transverse bar, limiting the motion of the handle end
of the lever in an upward direction. It should be understood that there is a
duplicate frame similar to that brought into view, on the other side of the
machine, about 18 inches apart, and connected by transverse bars. To prevent
the lever from swerving laterally, there are at the handle ends two upright bars,
between which the lever moves. The saw, after having once entered the ice,
will only require from two to four men to work it; and it should not be taken
out of the ice till after the distance required to be cut through is accom-
plished. The saw can be guided by the lever in any direction, so as to cut
the ice into pieces most convenient for removal, either by pushing them under
the adjacent floor of ice, or by dragging them out of the ship's track into clear
Water.
ICHNOGRAPHY, in Drawing, is synonymous with the term plan, such as
is exhibited in an horizontal section of a building, or of any other object,
which shows the true dimensions to a scale of every part in the line or plane
through which the section is made.
IGNITION, in its general sense, properly signifies the setting fire to any
substance. But the sense is more usually limited to the kind of burning which
is not accompanied with flame, such as that of metals, stones, and other
substances, which become red hot without melting.
ILLUMINATING. A kind of miniature painting, anciently much prac-
tised for illustrating and adorning books, but now, comparatively to the other
modes of illustration, but little practised, being chiefly confined to very expensive
publications, of which a very few copies are intended to be taken, or to the
adornment of manuscripts. Formerly, besides the writers of books, there were
artists whose profession was to ornament and paint manuscripts, who were
called illuminators. . The writers of books first finished their part, and the
illuminators embellished them with ornamented letters and paintings. In old
manuscripts blanks are frequently found, which were left for the illuminators,
who never filled them up. Some of the ancient manuscripts are gilt and
burnished in a style superior to later times, and the colours are so excellent,
as to indicate the exercise of great skill in preparing them.
IMPACT, in Mechanics, the simple or single action of one body upon
another, to put the latter, if at rest, in motion; or, if it be moving, to increase,
retard, or alter the direction of its motion. The point against which the im-
pelling body acts is called the point of impact.
IMPALPABLE POWDERS. Powders so finely levigated, that the particles
of which they are formed cannot be distinguished by the senses, more especially
that of feeling. Fine pigments, prepared by a flat stone and muller, are
reduced to this state.
IMPENETRABILITY is commonly understood to imply that quality of a
body by which it cannot be pierced; but in Physics the term has a different,
or more refined signification. It is therein defined to be that property of a
body by which it prevents any other body from occupying the space in which
the former is. Two particles of matter cannot exist at the same time in the
same place, for as long as one retains its place, it must necessarily exclude the
other. Indeed, were the case otherwise, each body might be successively
absorbed into the substance of another, till the whole frame of the universe,
collapsing to a point, were lost in the vortex of annihilation. The fact of the
impenetrability of even water is easily demonstrated. If a solid body be
plunged into a vessel filled with water, a portion of the water will overflow
exactly equal to the bulk of the solid body immersed, which shows that it is
only a change of places of the substances.
IMPULSE, in Mechanics, the single or momentary action or force by which
INDELIBI,E. 739
a body is impelled by another body, striking it, and is distinguished from
continued force, such as pulling, pushing, or pressure. Mr. Adams, in his
Lectures on Natural and Eaſperimental Philosophy, justly observes, “We are
forced, by the evidence of every phenomenon in nature, by every experiment
in philosophy, to conclude that impulse is the only material cause of motion.
All the properties of matter are such as fit them to act, and to be acted upon,
in a mechanical way. They are all such as can be adapted to the known
principles of mechanism among artists. We are therefore bound by every
rule of sound reasoning, to consider it as the cause of all the motion, and
continuance of motion, in the material universe. It is the one certain and
only universally known cause; for neither the properties of matter, nor expe-
riment, nor observation, afford any other.”
INCENSE. See FRANKINCENSE. -
INCH. The twelfth part of a foot; it contains three barley-corns, or
twelve lines.
INCIDENCE, or LINE of INCIDENCE, in Mechanics, is the direction in
which one body presses or strikes upon another.
INCINERATION. The combustion of vegetable or animal substances, for
the purpose of obtaining their ashes or fixed residue.
INCLINATION, in Geometry and Mechanics, the mutual tendency of two
lines, planes, or bodies, to each other, making, at the point where they meet,
an angle, called the angle of inclination. Thus, the inclination of one line to
another, is the acute angle which those lines make where they meet.
INCLINED PLANE. One of the mechanic powers or simple machines by
which weights may be elevated with great facility. If a heavy body be sus-
pended freely in space, or against a vertical plane, it is manifest that a weight
equal to itself must be employed to sustain it. If, on the other hand, it rest on
a horizontal plane, the whole weight is sustained by the plane. But if the body
rest on a plane at all inclined to the horizon, a part only of the weight is
sustained by the plane. Let A B be a plane
inclined to the horizon; D, a body supported
on the plane by means of the weight or power
E; if the experiment be made by carrying a
cord over a fixed pulley, as in the diagram, it
will be seen that while the cord continues
parallel to the plane, the power E will bear to
the weight D the same proportion as B C to
B A ; that is, as the height of the plane to its
length. If the length of A B be six feet, and
the height one foot, a power of one pound will balance six pounds on the plane;
if the height be two feet, one pound will balance three, and so on. To ascertain
the power obtained by this contrivance we must therefore divide the length of
the plane by the height. If the power act parallel to the base, the power is to
the weight as the height is to the length of the base. When the power acts
parallel to the plane, the power, weight, and pressure on the plane will be
proportional to the three lines B C, B A, and A C. For if the weight be
represented by a b, by the resolution of forces this may be decomposed into a c,
c b, one perpendicular and the other parallel to the plane. Now it is clear that
the one which acts perpendicularly on the plane will exert an equivalent
pressure, while the part that is parallel to the plane must be sustained by the
power. Hence the power, weight, and pressure, are proportional to the sides
of the small triangle a b c, which is similar to the large one A B C. If the
end of the cord be raised above the parallel direction, the pressure on the plane
will be diminished, but if it be depressed below the parallel direction, the
pressure will be increased, but in both cases a greater power will be required
to move the body up the plane. It is, we apprehend, needless to state examples
of the application of this method of increasing our power, as its use in assisting
to raise bodies to small elevations must be abundantly obvious.
INDELIBLE. Something that cannot be cancelled or effaced, as indelible
ink. See ANACARDIUM and INK.

740 INKS,
INDEX, in Mechanism, is a light rod, similar to the hand of a clock
employed to point out the degrees marked upon a divided scale.
INDIGO. A blue colouring matter, extracted from the leaves and stalks of
the indigofera tincteria, or anil plant. The ancients were acquainted with this
dye under the name of Indicum. It is found both in the East and West
Indies, is spontaneous in China and Cochin. China, and is cultivated all over
those vast empires. The seed is sown in little furrows two or three inches
deep, and about twelve inches distance from each other. Though it may be
sown at all seasons, the moisture of the spring causes the plant to shoot up in
three or four days, and it is at maturity at the end of two months. When
gathered it is thrown into a large cistern, called the steeping vat, containing
sufficient water just to cover the vegetable. The matter begins to ferment,
sooner or later, according to the warmth of the weather, and the maturity of
the plant, generally occupying from six to twenty hours. When the liquor is
in a proper state of fermentation (which is known by its heat, its thickening, an
abundant froth that it throws up, and its blue colour, inclining to violet), it is
let out by cocks in the bottom, into another vat placed for that purpose. In
this second vat, called the beating vat, the liquor is strongly and incessantly
beaten with a kind of buckets full of holes, fastened to poles. This part of the
process requires the greatest precaution. If the beating, is ceased too soon, a
part of the colouring matter remains dissolved in the liquor; if continued a
little too long, a part of that which is separated is dissolved afresh. The exact
time for discontinuing the process is determined by taking up some of the liquor
occasionally in a little cup, and observing whether the blue fecula is disposed to
separate and subside. The whole being now suffered to rest till the blue matter
has settled, the clear water is let off by cocks in the sides, at different heights,
and the blue matter at the bottom is discharged by another cock into a third
wat, where it is suffered to settle for some time longer, then conveyed, in a half
fluid state, into bags of cloth, to strain off more of its moisture; and, lastly,
exposed to the air in the shade, in shallow wooden boxes, till it is thoroughly
drv.
†NERTIA of MATTER. The name given to a passive principle, by which
bodies persist in a state of motion, or rest, receive motion in proportion to the
force impressing them, and resist as much as they are resisted. See MEcHANIcs.
INFLAMMABILITY. That property in certain bodies which disposes
them to kindle or take fire readily.
INFUSION, is the operation of macerating or steeping any substance in
water or other fluid, hot or cold (but without boiling), so as to extract its soluble
parts. The liquid thus impregnated is called an infusion.
INGOT, is a term applied to small bars of gold, silver, copper, and other
metals, of a wedge-like shape in their transverse section. The metals are run
into this form for portability, the convenience of trade, and their easy application
in the arts.
INHALER. The name given to an apparatus having a breathing-pipe, by
which a patient inhales steam or other vapours, and sometimes particular gases
or airs, presumed to be beneficial in catarrhs, affections of the lungs, &c.
INJECTION. The operation of forcibly throwing any liquid or aeriform
fluid by means of a pump, syringe, or other suitable mechanism, into a vessel.
Thus, cold water is injected into the condenser of a steam-engine to effect a
V&Clill]]].
INKS, are fluid compositions designed for writing, drawing, and printing.
As there are a great variety of sorts, we shall treat them consecutively,
according to the following arrangement of the subject.
For Writing. 1. On black writing inks generally. 2. On common black
writing ink. 3. On best, or Japan ink. 4. Copying ink. 5. Indelible, or
indestructible ink. 6. Red ink. 7. Indestructible red ink. 8. Blue ink.
9. Yellow ink. 10. Green, and other coloured inks. 11. Cloth-marking ink.
12. Sympathetic, invisible, or secret inks. 13. Lithographic ink.
For Drawing. 14. Indian, and imitation Indian ink. I 5. Lithographic ink,
for drawing on stone or paper.
INKS. 741
For Printing. 16. Letter-press printing ink. 17. Red, and other coloured
ditto. 18. Copper-plate printing ink. 19. Lithographic printing ink.
For removing stains of ink, 20.
1. Black Writing Inks generally.—When any vegetable matter, containing the
gallic acid, is infused with a solution of iron in water, the gallic acid unites
with the iron, and a black liquor results, from which the colour, in the form of
an impalpable powder, is gradually precipitated. To prevent the latter effect,
it becomes necessary to render the liquor viscid, or of greater specific gravity;
and this is best effected by the addition of a gum which is perfectly soluble in
water, as this gum, besides keeping the black feculae suspended in the liquor,
serves also to prevent the ink from sinking or spreading on the paper, and
likewise to defend it, in the manner of a varnish, from the action of the air.
Ink may therefore be regarded as merely a gallate of iron, combined with a
little mucilage. It follows, from this view of the matter, that the same, or very
nearly the same, kind of black liquid may be produced from a great variety of
substances, and, therefore, to make
2. Common Black Writing Ink.—It becomes the business of the manufacturer to
select such materials as will produce the required quality at the least cost to
himself. . It is commonly supposed that nut-galls are employed on a large
scale for this purpose, but the low price at which common ink is sometimes sold
per gallon, renders this improbable ; and that such an expensive material
(however good) is not necessary, the reader has only to consider that the dyer
makes a variety of good blacks without it. Of all known vegetable matters,
sumach approaches nearest to galls, and forms a very cheap substitute; com-
bined with the sulphate of iron (green copperas) it makes a very rich black ink,
but it requires some peculiar management to prevent its becoming thick.
Logwood, from the great affinity of its colouring matter to the oxide of iron,
renders it a most desirable substitute for galls. It is well known to be partially
used with galls in making ink; but very good common ink may be made from
it without any other astringent matter. Valonia, the barks of the oak, chestnut,
and many other trees, may be very advantageously applied as useful substitutes
for galls in making common ink, and are well deserving of the attention of the
manufacturer who may not be acquainted with their properties. A good common
ink is made in the following manner: Take 8 ounces of Aleppo galls, in coarse
powder, and 8 ounces of logwood, in thin chips; boil these in six quarts of soft
water for an hour, and supply the waste from evaporation by the addition of
fresh water; strain the decoction through a hair sieve, and then add 5 ounces
of sulphate of iron, and 3 ounces of gum Senegal, of ordinary quality. Stir the
mixture until the latter is dissolved, then let it subside for twenty-four hours,
after which, decant the ink, and preserve it in bottles of glass or stone ware for
use. This recipe, it is evident from the preceding remarks, may be considerably
varied without material prejudice to the quality of the article; but it should be
borne in mind that galls possess more intrinsic value (without reference to their
prime cost) than their substitutes, as a given weight of them yields a greater
quantity of black precipitate than any of the others; the current price, as well
as the quality of the galls, will therefore have to be duly estimated, and in
apportioning the substitute a greater quantity must be used.
3. Best, or Japan Ink.—M. Ribaucourt, who has paid particular attention to
the process of making black ink, has drawn the following inferences from his
experiments. That logwood, from its disposition to unite with the solutions of
iron, is a valuable ingredient in the making of ink, rendering it not only of a
very dark colour, but less capable of change from the action of acids or of the
air. That sulphate of copper, in a certain proportion, gives depth and firmness
to the colour of the ink. That gum has all the advantages we have before
named. That sugar (although it has some bad qualities) is of use in giving a
degree of fluidity to the ink, which permits the dose of gum to be enlarged
beyond what the ink would bear without it. That water is the best solvent.
From these considerations M. Ribaucourt has given the following directions for
the composition of good ink, namely, 8 ounces Aleppo galls, 4 ounces logwood,
4 ounces sulphate of iron, 3 ounces gum arabic, 1 ounce sulphate of copper,
5 s
742 IN KS.
and 1 ounce of sugar candy The galls and logwood to be boiled in 12 lbs
of water, till reduced to 6 lbs. and after straining, the other ingredients are to
be added. This ink flows from the pen of a jet black, and from the gum being
in greater proportion to the liquid than in the previous recipe, the writing dries
with a gloss upon it; hence it has been called Japan ink. If it is desired to
give it more gloss, the gum may be increased, to which some more sugar must
be added to give it equal fluidity; but an excess in the latter ingredient renders
papers written upon with it liable to stick together, upon contracting the least
dampness.
M. Desormeaux, jun. an ink manufacturer of Spitalfields, gave an excellent
recipe for making ink some time since in the Philosophical Magazine; but as
his process does not differ essentially from those we have given, and as his
observations are confirmatory, as far as they extend, of our own, we shall only
notice the points of difference in his communication. He directs the sulphate
of iron to be calcined to a whiteness, and employs coarse brown sugar instead
of sugar-candy, the acetate of copper instead of the sulphate, and only in one-
fourth the quantity; and recommends the ink to be agitated twice a day for a
fortnight before it is poured from the dregs and corked up for use. These
variations appear to be judicious and deserving of imitation.
Dr. Lewis and others have recommended vinegar as the menstruum in pre-
ference to water; on which, as well as the sulphate of copper of Mr. Ribaucourt,
Dr. Ure acutely observes, “I have found an inconvenience in the use of either,
which, though it does not relate to the goodness of the ink, is sufficiently great,
in their practical exhibition, to forbid their use. The acid of the vinegar acts
so strongly upon the pen, that it very frequently requires mending; and the
sulphate of copper has a still more unpleasant effect upon the pen-knife. It
seldom happens that when a pen requires mending, that the ink is wiped very
perfectly from it; and often, when the nib is only to be taken off, it is done
without wiping at all. Whenever this is the case, the ink immediately deposits
a film of copper upon the knife, and by superior electric attraction of the
sulphuric acid, a correspondent portion of the edge of the knife is dissolved,
and is by this means rendered incapable of cutting until it has been again set
upon the hone.
4. Copying Ink,+for transferring writings to thin unsized paper is prepared
by the simple addition of a little sugar to common writing ink. The powerful
affinity of water to sugar, causes the damp paper to immediately absord the
ink by the powerful aid of the copying-machine. See Copying PREss.
5. Indelible Ink.-It is well known that common writing ink may be easily
obliterated by the application of oxymuriatic acid, or aqueous chlorine; it
therefore becomes an important object to employ those substances which shall
be indestructible by the application of any process that will not at the same
time destroy the material upon which it shall be used. For this purpose
Mr. Close has recommended twenty-five grains of copal in powder, dissolved in
two hundred grains of oil of lavender, by the assistance of a gentle heat, and
then mixed with two and a half grains of lamp-black, and half a grain of
indigo. A little oil of lavender, or of turpentine, may be added if the ink be
too thick. Mr. Sheldrake suggests that a mixture of genuine asphaltum, dis-
solved in oil of turpentine, amber varnish, and lamp-black, would be superior to
the foregoing. For many common purposes the introduction of a little lamp-
black into the composition of common ink will answer sufficiently. In the
Journal of the Royal Institution the following process of making an indelible
ink has been recommended:—Let a saturated solution of indigo and madder in
boiling water be made in such proportion as to give a purple tint; add to it
from one-sixth to one-eighth of its weight of sulphuric acid, according to the
thickness and strength of the paper to be used. This makes an ink which
flows pretty freely from the pen; and when writing which has been executed
with it is exposed to a considerable but gradual heat from the fire, it becomes
eompletely black, the letters being thoroughly burnt in, and charred by the
action of the sulphuric acid. If the acid has not been used in sufficient quantity
to destroy the texture of the paper, and reduce it to the state of tinder, the
INKS. 743
colour may be discharged by the oxymuriatic and oxalie acids, and their com-
pounds, though not without great difficulty. When the full proportion of acid
has been employed, a little crumpling and rubbing of the paper reduces the
carbonaceous matter to powder; but by putting a black ground behind them
they may be preserved; and thus a species of indelible writing ink is procured,
(for the letters are in a manner stamped out of the paper) which might be
useful for some purposes, perhaps for the signature of bank notes. (See the
inks for marking linen.) When writing with common ink has been effaced by
means of aqueous chlorine, the vapour of sulphuret of ammonia, or immersion
in water impregnated with this sulphuret, will render it again legible. Or if
the paper that contained the writing be put into a weak solution of prussiate of
potash, and when it is thoroughly wet, a little suphuric acid be added to
the liquor, so as to render it slightly acidulous, the same purpose will be
answered.
6. Red Inks.--Steep one pound of powdered Brazil wood, and one ounce of
pºrº cochineal, in two gallons of vinegar. Let them macerate for twelve
hours. Then put the whole on to a slow fire, with four ounces of alum, and
one ounce of lump-sugar, in a pewter vessel, until a good red colour is
obtained. When the ink is settled it may be decanted, pouring it through a
piece of cloth into bottles, and preserved for use. Cochineal is a very expen-
sive article, and although it is usual to recommend its introduction into red ink,
on account of the richness of its colouring matter, we know from experience
that it is by no means a necessary ingredient, and that a beautiful and very
permanent red may be obtained without it. We have before us a recipe,
written fifteen years ago in the identical red ink it is descriptive of the process
of making; the colour is extremely beautiful, nor in the least deteriorated by
the lapse of time. The process differs only from the above recipe in using no
cochineal, but it contained as much alum as the liquid would dissolve in its cold
state; the Brazil wood was macerated during a night, and was very gently
boiled in an unglazed earthen pot on the next day, for half an hour; afterwards
one pound of Senegal gum, and a quarter of a pound of lump-sugar, were
added. With so large a proportion of mucilage as just mentioned, and so much
alum, it is probable that vinegar may be dispensed with, and that water alone,
which is a good menstruum for the colouring matter of Brazil wood, will answer
very well, and materially cheapen the ink. Care should be taken to discontinue
the boiling after the full bright red is obtained, as by continuing it the colour
darkens; also, that copper or iron vessels should not be used, unless they are
perfectly coated with tin in every part. A solution of tin heightens the red
colour, and tends to restore it, if it has acquired a purple tint.
7. Indestructible Red Ink may be made by dissolving one ounce of copal in
seven ounces of oil of lavender, and adding thereto three ounces and a half of
}. vermilion. If found too thick for the pen, add a little more oil of
avender.
8. Blue Ink.—Take sulphate of indigo (indigo dissolved in sulphuric acid, it
may be had of the dyers), and dilute it with water till the desired tint is
obtained. It is with this sulphate, very largely diluted, that the faint blue lines
of ledgers and other books are ruled. If the ink were used strong, it would be
neces: a y to add chalk to it, to neutralize the acid.
9. Yellow Ink.—Half a pound of French berries, boiled with a little alum in
a quart of water, or vinegar and water.
10. Green and other coloured Inks.-A mixture of the above blue and yellow
inks will make a green; a mixture of the red and yellow will make an orange ;
of the blue and red, a purple ; of the black and yellow, a brown. Inks of all
colours may, however, be very readily obtained by rubbing down with water
any of the water-colours prepared in cakes, for artists; or by using a strong
decoction of any of the ingredients used in dyeing, with a little alum and gum.
11. Marking Linen.—Mr. Haussman has given some compositions for marking
pieces of cotton and linen, previous to their being bleached, which are capable
of resisting every operation in the processes both of bleaching and dyeing, and
consequently might be employed in marking linen for domestic purposes. One
744 INRS.
of these consists of asphaltun, dissolved in about four parts of oil of turpentine,
and with this is to be mixed lamp-black or black-lead in fine powder, so as to
make an ink of a proper consistence for printing with types. Another, the
blackish sulphate left after expelling oxygen gas from oxide of manganese with
a moderate heat; being dissolved and filtered, the dark grey pasty oxide left
on the filter is to be mixed with a very little of a solution of gum tragacanth,
and the cloth marked with this is to be dipped in a solution of potash or soda,
mild or caustic, in about ten parts of water. The anacardium, or cashew nut,
it is well known, yields an inflammable caustic liquor, which alone forms a
very useful marking ink, as any thing written on limen or cotton with it is of a
brown colour, which gradually grows blacker, and is very durable. The ordi-
nary marking ink sold in our shops is made in the following manner:—Take
lunar caustic (nitrate of silver), 5 scruples; gum arabic, 5 scruples; sap-green,
I scruple; water, 1 ounce; put these together in a small bottle, and the ink
is formed. In using it, the linen is first wetted with the following mordant;--
1 ounce of soda to 2 ounces of water. The marking ink should not be used
until the mordant has dried upon the linen.
12. Sympathetic, Invisible, or Secret Inks, are such as do not appear after they
are written with, but which may be made visible at pleasure, by certain means
used for that purpose. They are of considerable antiquity; for it appears that
Ovid recommends the maidens of his days, who wished to correspond secretly
with their lovers, to write with fresh milk, which when dried might be made
visible by rubbing over it ashes or rust. Pliny, who was better informed than
Ovid in such arts, though probably less inclined to practise them, recom-
mended the milky juice of certain plants for the purpose; but the use of such
things is superseded by the discoveries of modern chemists, who have intro-
duced to our notice a great variety of secret inks, the best of which we find
selected in the Oaford Cyclopædia ; they are as follow :—Dissolve some sugar
of lead in water, and write with the solution. When dry, no writing will be
visible. When you want to make it appear, wet the paper with a solution of
alkaline sulphuret (liver of sulphur,) and the letters will immediately appear of
a brown colour. Even exposing the writing to the vapours of these solutions
will render it apparent.—Write with a solution of gold in aqua-regia, and let
the paper dry gently in the shade: nothing will appear; but draw a sponge
over it, wetted with a solution of tin in aqua-regia, the writing will immediately
appear of a purple colour.—Write with an infusion of galls, and when you wish
the writing to appear, dip it into a solution of green vitriol; the letters will
appear black.-Write with diluted sulphuric acid, and nothing will be visible.
To render it so, hold it to the fire, and the letters will instantly appear black.--
Juice of lemons or onions, a solution of sal ammoniac, green vitriol, &c. will
answer the same purpose, though not so easily, nor with so little heat.
Green Sympathetic Ink. — Dissolve cobalt in nitro-muriatic acid, and
write with the solution. The letters will be invisible till held to the fire, when
they will appear green, and will disappear completely again when removed
into the cold. In this manner they may be made to appear and disappear at
pleasure. A very pleasant experiment of this kind is to make a drawing
representing a winter scene, in which the trees appear void of leaves, and to
put the leaves on with this sympathetic ink; then upon holding the drawing
near to the fire, the leaves will begin to appear in all the verdure of spring, and
will very much surprise those who are not in the secret.
Blue Sympathetic Ink. — Dissolve cobalt in nitric acid; precipitate the
cobalt by potass; dissolve this precipitated oxide of cobalt in acetic acid,
and add to the solution one-eighth of common salt. This will form a
sympathetic ink, that, when cold, will be invisible, but will appear blue
by heat. -
13. Lithographic Ink.-As the art of lithography is treated of generally
under its initial letter in this work, we shall in this place simply notice the
autographic ink, suitable for transferring to stone the writings or drawings which
have been executed on paper prepared for the purpose. This ink ought to be
mellow, and somewhat thicker than that used for drawing or writing immle-
• INKS, -- 745
diately on stone; so that when it is dry on the paper, it may be still sufficiently
viscous to cause it to adhere to the stone by simple pressure. The follow-
ing is the mode of preparing it: dry soap, 100 drachms; white wax, pure,
100 ditto; mutton suet, 30; shellac, 50; mastic 50 ; and lamp-black, (fine, from
the combustion of resin,) 30 to 35 drachms. These are to be melted over
a brisk fire in a metal pot over a chafing dish; first melt the soap and the
suet, then add the shellac very gradually; next the soda, a little at a time, and
after this the mastic, taking care to stir it from time to time with a wooden
spatula; lastly the lamp-black, stirring it all the time. When these materials
are well incorporated, they are poured on a plate of cast iron, made warm, and
oiled, in order that the composition may be easily detached from it. Ledges of
wood are put on the plate to keep the thickness of the composition uniform,
which when congealed, but still warm, is cut into sticks, like Indian ink.
14. Indian Ink.-The genuine article, which is used by the Chinese for
writing with a brush, as well as for painting upon their soft, flexible paper, is
ascertained by experiment and information to consist of lamp-black and size,
animal glue, with the addition of perfumes or of other substances not essential
to its quality as an ink. The fine soot from the flame of a lamp or candle,
received by holding a plate over it, mixed with clean size from shreds of parch-
ment of sheep and goat skins, will make an ink equal to that imported. We
have been in the habit of using, during many years, both the genuine and
the imitation Indian ink indifferently, without being able to discover that either
merits a preference.
15. Lithographic Drawing Ink.—This composition is the same as the ink
used for writing upon stone and lithographic transfer paper, already described;
the artist rubbing it down usually upon a slab, as Indian ink, for his use.
16. Letter-press Printing Ink is a very smooth and jet black oil paint.
The consistence and tenacity of the oil in this composition are greatly increased,
and its greasiness diminished, by means of fire. Linseed oil, or nut oil, is
made choice of for this use. The nut oil is supposed to be the best, and is
accordingly preferred for the black ink, though the darker colour it acquires
from the fire renders it less fit for the red. It is said, that the other expressed
oils cannot be sufficiently freed from their unctuous quality. Ten or twelve
gallons are set over the fire in an iron pot, capable of holding at least half as
much more; for the oil swells up greatly, and its boiling over into the fire
would be very dangerous. When it boils, it is kept stirring with an iron ladle;
and if it do not of itself take fire, it is kindled with a piece of flaming paper
or wood. It is found that mere boiling, without setting it on fire, does not
give it a sufficiency of the drying quality. The oil is suffered to burn for half
an hour or more, and is then extinguished by covering the vessel close, and
excluding the air. The boiling is continued with a gentle heat, till the oil has
attained the proper consistency, in which state it is called varnish. It is neces-
sary to have two kinds of this varnish, a thicker and a thinner, (from the
greater or less boiling it has received,) which are occasionally mixed together,
to suit different purposes; for that which answers well in hot weather, becomes
too thick in cold, and large characters or type do not require such stiff ink as
the small. The thickest varnish, when cold, may be drawn into threads, like
glue; and the workmen taking out small quantities, from time to time, judge
of the proper degree of boiling required, by testing its tenacity in that manner.
The oil loses by the boiling about one-eighth of its weight. The varnish readily
mingles with fresh oil, and it will unite with mucilages, into a mass that is after-
wards diffusible in water. About one-seventh part, by weight, of lamp-black
is added to the varnish, to give it the depth of colour. Boiled with caustic
alkali, a soapy compound is formed, and printers availing themselves of this
fact, are in the habit of cleaning their types by soap-makers' lees and a brush.
It is said that when very new oil is used in making ink, it does not readily
dry without the addition of litharge, or the oil of turpentine, and these addi-
tions (which are not necessary in old oil) cause it to stick very hard to, and
clog up the types.
17. Ited and other coloured Printing Inks, are made from linseed oil, boiled
746 INKSTANDS.
into a varnish, as described in the black ink, with the addition of some dry
pigment of the required colour, which is ground up with the varnish, with a
stone and muller in the manner of oil paint. Thus, for preparing the bright
red printing ink, vermilion is ground up with the varnish, in such quantity as
will give the required depth of tint. In like manner for blues, yellows, oranges,
greens, &c. the Prussian blue, indigo, orpiment, chrome, red and orange lead,
verdigris, and in general the pigments used by house painters, are similarly
combined with the varnish.
18. Copperplate Printing Ink is of a somewhat similar kind to that used for
type printing, but the oil is less boiled, and the varnish is in consequence much
more fluid; and instead of lamp-black, they either use the black imported
from Frankfort, (which is said to be the charcoal of vine twigs, prepared in a
peculiar manner,) or when this cannot be procured, or is too costly, the finest
ivory black they can obtain.
19. Lithographic Printing Ink differs from that used in typography, only in
being a much thicker varnish ; and the lamp-black which is used as the colour-
ing matter is not mixed with it in the mass, but small portions of the varnish
are taken from time to time, as it is required, and the lamp-black then only
ground up with it for immediate or very early use. See LITHogRAPHY.
20. Removing Stains of Ink. The stains of ink on cloth, paper, or wood, may
be removed by almost all acids; but those acids are to be preferred which are
least likely to injure the texture of the stained substance. The muriatic acid,
diluted with five or six times its weight of water, may be applied to the spot,
and after a minute or two may be washed off, repeating the application as often
as may be found necessary. But the vegetable acids are attended with less
risk, and are equally effectual. A solution of the oxalic, citric (acid of lemons),
or tartaric acids in water, may be applied to the most delicate fabrics, without
any danger of injuring them; and the same solutions will discharge writing,
but not printing ink. Hence they may be employed in cleaning books that
have been defaced by writing on the margin, without impairing the text.
Lemon-juice, and the juice of sorrel, will also remove ink stains, but not so
easily as the concrete acid of lemons, or citric acid.
INKSTANDS. Utensils for holding ink for the convenience of dipping a
pen into them. They were formerly chiefly made of horn, but now generally
of glass or metal. It is not our intention to describe the ordinary kinds, that
are familiar to every eye, but only the recent elegant improvements which have
been made upon them.
Edwards's Patent Inkstand is one
of great convenience and stability, ||||||||||
and not very liable to get out of order. .* ||
It is represented in the subjoined en-
graving, which affords a sectional view |
of the interior. a a shows the top and
bottom of an external cylindrical mº ill!!
casing of bronze, b is the ink imbibed | | #|| |
by a quantity of loose hair or wool, -- -55
contained in a cylindrical glass cup
c c, of considerable thickness, the upper
part of which is closed by a glass pis-
ton d, accurately ground to fit the
cylinder, and so as to permit it to move
easily up and down. On the upper
surface of the glass piston, a hollow
screw e with a disc of metal at the
end, is made to operate by pressure
downwards, when the top piece f is
turned by the finger and thumb; the
latter turns the solid screw, and causes
the hollow screw to advance or recede
with a sliding motion, so as to press
#:
&
||||||||||||||||||||||||
| | "lºſ lift
|il', tº it it.


INKSTANDS. 747
uniformly upon the piston without the friction of turning against its surface.
At the lower part of the reservoir, an aperture is made, into which a tube
is fixed that conducts the ink to a little pen-supplying cup g, when the wool is
compressed by a turn of the screw, forcing down the piston. The little cup,
previously empty, is thus instantly supplied with fresh ink, with no more trouble
than taking up a pen; and should a little more ink be forced into the cup than
is necessary, by carelessly turning the screw too far, it runs over, and is caught
in the little saucer shown below. When the inkstand is not in requisition, a
half turn of the screw the reverse way causes the ink to flow back again, as
the wool being thereby relieved of the pressure, re-absorbs the fluid. The ink
being thus returned into the reservoir, none can be spilled, even if upset; it is
preserved from the contact of the air, consequently from drying up, as well as
from dust, and it may be instantly brought into use whenever required. These
are decided advantages, which peculiarly recommend it for the use of persons
travelling.
Patent Caoutchouc Inkstand.—Mr. Doughty, the ingenious manufacturer of
pens with ruby and rhodium nibs, having discovered the injury that those pens
received from being incautiously struck against the glass of common inkstands,
contrived to manufacture an interior bottle of Indian rubber, of nearly the form
of the external ornamental case, as shown in the annexed section of one of his
&ººk
*
º
* *
º: *" ºr -º-º-º:
vºº: , ; ** - . . .
** - - - - - - - - -
... - % Rº N
É
º - %. § -
WSWAP-
r = -----
-----------ºr---------
- ". . . ºfflº-
Z(N -
.wº-w,
.*.
º
elegant inkstands. The stopper is of a conical form, and is so fixed in the
screwed head or cap as to have a little lateral play therein, which admits of
its adapting itself exactly to the conical neck of the inkstand, and when
screwed down, prevents the possibility of leaking; and that the ink may not
corrode the metal stopper, the latter is coated with gold or platinum.
Płorsley and Cooper's Patent Inkstand.—The peculiarity in this invention
consists in the forming of convenient and perfectly air-tight stoppers, in a
substance, not liable to corrode. It is effected by bringing into contact two
circular discs of glass, the flat surfaces of which being ground to true planes,
are opposed to each other and united by a central pivot, rivetted to a bar of
metal fixed above them, across the mouth of the vessel. Each plate has an
aperture of proper dimensions for dipping the pen, and the upper plate is













748 IODINR AND IODIC ACII).
rovided with two projecting studs, at equal distances from the central pivots.
The thumb and fore finger being applied to these two studs, the upper disc is
easily turned either to the right or left; one way brings the apertures opposite
to each other, which opens the inkstand, and being moved the other way, the
unperforated part of the upper disc is slided over the stationary aperture of the
lower, and perfectly closes it. The
rubbing surfaces are slightly oiled,
which renders the motion smooth
and easy, and the sealing perfect.
Fig. 1. affords a perspective view
of an inkstand of this kind, made
of very thick cut glass; the discs
or stoppers of which are sur-
rounded by a metallic ring, and
kept down in their places by an
horizontal metallic bar, into which
the pivot of the discs is fitted. In
this figure it will be perceived that
the inkstand is shut, the aperture
in the upper plate being over the
unperforated part of the lower. On
turning the studs a quarter round,
|
they are stopped by striking against § ºW º
the cross bar, when the two holes - sº sº º
coincide, (as shown in the annexed
sections), by which the inkstand is
opened. Underneath the bar (which
is shown by a transverse section) a
steel spring is fixed, which keeps the º ſº- :*
discs in close yet easy contact. The * º
º º º ‘....". tºº º
sists in the facility and expedition
with which the #ºnd . be opened and closed air tight, the simplicity of
the construction, and the incorruptibility of the materials. -
INSOLATION. A method of preparing certain fruits, drugs, &c. by expos-
ing them to the heat of the sun's rays, either to dry, to maturate, or to render
them acid; as is done in figs, raisins, vinegar, and many other products.
INTAGLIOS. Precious stones, on which are engraved the heads of eminent
men, such as are usually set in seals, rings, &c.
INTEGER, in Arithmetic, signifies a whole number, in contradistinction to
a fraction.
INTEGRAL, in Philosophy, is an appellation given to parts of bodies which
are of a similar nature to the whole. -
INTEGRAL CALCULUS is the reverse of the differential calculus, and is
the finding of the integral from a given differential, and corresponds with the
inverse method of fluxions.
INTERMEDIATES. A term made use of in Chemistry in relation to affi-
nity; thus, oil has no affinity to water unless it be previously combined with an
alkali; it then becomes soap, and the alkali is said to be the intermedium which
causes the union.
INTRADOS. The internal curve of the arch of a bridge.
INVERSE PROPORTION, or INverse RATIo, in Philosophy, is that in
which more requires less, or less requires more. Thus in the case of light and
heat flowing from a luminous body, the light and heat are less at a greater dis-
ance and greater at a less distance.
IODINE AND IODIC ACID. Iodine is a peculiar and compounded prin-
ciple; it was discovered in Paris in 1811 by M. Courtois, a saltpetre manufac-
turer, who observed a rapid corrosion of his vessels in his processes for obtaining
soda from the ashes of sea weeds; and in searching for the cause of the corro-
sion, he made the discovery of this important substance. It is from sea weeds
|
|
lº
ºfflººd
====E---------
*~wr.









IRIS METAL ORNAMIENTS. 749
alone that iodine can be obtained; it has not yet been decomposed; it is of a
greyish-black colour, and metallic lustre; soft and friable to the touch ; taste
acrid, and a deadly poison. It gives a brown stain to the skin, which speedily
vanishes by evaporation. The specific gravity of iodine at 629, is 4.948: it
dissolves in 7,000 parts of water, and the solution is of an orange yellow colour,
and in small quantities tinges raw starch of a purple hue. Iodine is incom-
bustible; but with azote it forms a detonating compound, and in combining
with several bodies it produces the phenomenon of combustion. The oxide of
sodium, and the subcarbonate of soda are completely decomposed by it. It forms
with sulphur a compound of greyish black, radiated like sulphuret of antimony.
Iodine and phosphorus combine with great rapidity at common temperatures,
and produce heat without light. Hydrogen, whether dry or moist, does not
seem to have any action on iodine at the ordinary temperature; but if we
expose a mixture of hydrogen and iodine to a red heat in a tube, they unite
together, and hydriodic acid is produced, which gives a reddish brown colour
to water. Charcoal has no action upon iodine. Several of the metals, as zinc,
iron, tin, mercury, attack it readily, even at a low temperature, provided they
be in a divided state. Iron is acted upon by iodine in the same way as zinc, and
a brown iodine results. Antimony presents with iodine the same phenomena
as tin. The iodines of lead, copper, bismuth, silver, and mercury, are insoluble
in water; this is at least the case with the above-mentioned metals. There are
two iodines of mercury; the one yellow, the other red; both are fusible and
volatile. When iodine and oxides act upon each other in contact with water,
its hydrogen unites with iodine to form hydriodic acid; while its oxygen, on
the other hand, produces with iodine iodic acid. Iodine of mercury has been
proposed for a pigment. Iodine has been most successfully applied medicinally
for reducing the goitre and glandular swellings, See Ure's Dictionary.
IRIDIUM. A new metal, to which that mame was given by its discoverer,
Mr. Tennant, from the striking variety of colours it affords whilst dissolving in
muriatic acid. On examining the black powder left after dissolving platina,
Mr. Tennant found it to contain two distinct metals never before noticed, which
he named iridium and osmium. Lead unites with iridium easily, but separates
by cupellation, leaving the iridium in the cupel as a coarse black powder.
Copper forms with it a very malleable alloy, which, after cupellation, with the
addition of lead, leaves a small proportion of the iridium, but much less than
in the preceding instance. Silver forms with it a perfectly malleable compound,
the surface of which is tarnished merely by cupellation; yet the iridium appears
to be diffused through it in fine powder only. Gold remains malleable and
little altered in colour, though alloyed with a considerable proportion; nor is it
separable either by cupellation or quartation. If the gold or silver be dis-
solved, the iridium is left as a black powder.
IRIS METAL ORNAMENTS. A patent was taken out a few years ago
by Mr. Barton, of the Mint, for a very ingenious method of ornamenting
steel and other metals with the prismatic colours. It is effected by engraving
with an engine lines on the surface of the metals of extreme minuteness, so as
to divide a lineal inch into from 2000 to 10,000 equal parts. Mr. Barton has
sometimes proved the correctness and stability of his engine, when drawing
lines 2000 in an inch, by leaving out one line intentionally, then taking the
machine to pieces; afterwards, on putting it together again, he has introduced
the omitted line in its place, without causing it to be distinguishable from the
rest.
In applying the principle of striated colours to ornament steel, the effect or
pattern is produced upon the polished surface by the point of a diamond; so
that either the whole, or a part of the surface, is covered with lines or grooves,
whose distance may vary from the one-thousandth to the ten-thousandth of an
inch. When these lines are most distant, the prismatic images of any luminous
body, seen by reflection from the polished surface, are nearest one another, and
the common colourless image; and when the lines are least distant, the coloured
images are farthest from one another, and the colours are most vivid. In day-
light the colours produced by these minute grooves are scarcely distinguished,
5 c
750 - IRON.
unless at the boundary between a dark and a luminous object. In sharp
lights, however, and particularly in that of the sun, the colours shine with €X-
traordinary brilliancy, and the play of tints which accompany every luminous
image can only be equalled by their matchless exhibition in the reflections of
the diamond. Steel dyes are engraved in this manner, from which impressions
are afterwards taken for the fabrication of various articles, in which the design
of the original is very faithfully transferred.
IRON. A metal of a bluish-white colour, of great hardness and elasticity;
very malleable, and exceedingly tenacious and ductile. It is the most abundant,
the most important, and the most valuable of all the metals. Although a simple
undecompounded substance, it is not naturally found in this state, except in
comparatively minute quantities, but is the product of art. Some specimens
of native iron, nearly pure, have been found in Siberia and South America;
also many iron stones, rich in the metal, supposed to be of volcanic or
meteoric origin, have been found in numerous parts of the earth ; but all the
iron of commerce is obtained by chemical means. Iron is so universally dif-
fused as to form a constituent part of almost all animal, vegetable, and mineral
substances. Unlike metals of inferior utility, its ores are not distributed in
thin veins, or scattered in minute particles, but are thickly stratified over
many thousands of square miles, chiefly in the northern regions of the earth,
where nature has been less profuse of her other benefits. The use of this metal
is of very great antiquity, though, on account of the difficulty of separating it
from its ores, and of working it, probably not so remote as the employment of
gold, silver, copper, and other comparatively soft metals, which are in many
places found in a pure metallic state. It is stated by some writers, that iron is
mentioned by Moses as the material of which knives and swords were fabri-
cated ; and that Herodotus mentions the presentation of a saucer, or vase of
iron, very curiously inlaid, by Alyattes, king of Lydia, to the Delphic oracle.
those ancient authors have been most incorrectly translated into our language;
and that the working and use of iron was unknown at those periods. At what
time the manufacture of iron was first attempted in Britain, cannot be precisely
ascertained. Some suppose (for it is in reality only a probable conjecture) that
the Phoenicians who wrought the tin mines of Cornwall, introduced into the
country men who were skilled in metallic ores, and capable of estimating their
value, by applying the minerals to such purposes as their own necessities or
the wants of the inhabitants might require. There is, however, much evidence
to favour the belief that iron was worked in this country during the time it was
in occupation by the Romans; and that during the establishment of the Danes
in England, the arts of mining and manufacturing the ores of iron were much
improved. It appears that the manufacture was at that period chiefly directed
to the fabrication of malleable iron, in what were called foot-blasts, of a similar
nature to those still used in remote uncivilized countries, of which Dr. Davy
has furnished us with an example in a Singalese smelting house of the present
day. The simplicity and cheapness of construction of this furnace is extremely
interesting, as showing what may be effected by very limited means, and that
the large capitals and immense laboratories employed by our present iron
manufacturers, however necessary they may be to the production of a large
quantity of the metal, are by no means essential to the production of a good
quality; for it has been generally remarked, that the ruder the method employed
in any country for the reduction of iron, the better the quality of the metal is.
The observation holds good in Ceylon, and there is obvious reason why it should
be correct. Where the art is little advanced, the most tractable ores are selected,
and charcoal is the fuel always used, circumstances which are alone sufficient
to account for the iron obtained being excellent. Each furnace was, at its
mouth, about 1 foot and 4 inches, by 8 inches in diameter; about 3
feet deep, and terminated in the form of a funnel, over a shallow pit inclining
outwards. They were made in a bed of clay about 3 feet high, and 3 feet
wide, against which a light wall, about 10 feet high, was raised to protect the
bellows and operator, who was situated immediately behind. Each bellows
*
IRON. 751
consisted of a circular rim of wood, about 6 inches in diameter, and scarcely 2
inches high, fixed on a clay floor, and covered with moist cow-hide; in the
centre of which was a hole to admit air, and to receive a cross stick, to which
a cord was attached that was fastened above to an elastic stick. Each pair of
bellows was worked by a boy, who rested his back against a rope for the pur-
pose of support, and stepped alternately from the orifice of one bellows on to
that of the other, at each step forcing a blast of air into the furnace through a
ºl
tube of bamboo. The furnaces were charged with a mixture of iron ore,
broken into small pieces, and charcoal. The fires were kept up as strong as
possible till the ore was reduced, and the fused metal collected in a cake in the
ash-pit.
A. time when foot-blasts were used for separating the metal, the art of casting
iron was either altogether unknown, or in a state that it could not be prosecuted
with advantage. In the reign of Elizabeth, blast furnaces were of a sufficient
size to produce, with ores and the charcoal of wood, from two to three tons of
pig-iron per day, or from fifteen to twenty tons per week. It was only, how-
ever, in the most favourable situations for obtaining water-power that such
great products were obtained, and the greatest proportion of it was converted
into bar-iron by means of the refinery fire; but in many of the small works
the iron was “matured,” that is, made malleable, before it was drawn from the
furnace. Wood, however, becoming scarce, or being engrossed by the great
manufacturers, induced several enterprising individuals to attempt the substi-
tution of pit coal for making pig-iron. Mr. Simon Sturtevant, 1612, had a
patent granted to him, for thirty-one years, for that purpose. By the terms of
his patent he was bound to publish the nature and process of his invention,
which he did, in a quarto book, entitled Metallica ; this book, Mr. Gray says,
does not contain a particle of useful knowledge, but that it is an extremely
curious specimen of the pedantry usual in James's reign. Sturtevant failed in
executing his proposed plans, and was obliged, the following year, to render up
his letters patent, or monopoly. John Ravenson, Esq. succeeded Sturtevant in
1613, had a patent granted to him, wrote his book, entitled “A Treatise of
Metallica, but not that which was published by Mr. Simon Sturtevant.” Ravenson
states, that at that time an iron work usually required from 1000l. to 1500l. to
set it a-going, but that on his plan a capital of 100l. was fully adequate to
commence a work. The furnace itself was to cost but 10l. except the stones,
such furnace being capable of producing a ton of sow iron from each ton of pit
coal. This man, however, failed in his attempts to prove the correctness of his
statements, and resigned his patent. Several other unfortunate adventurers
followed Ravenson in succession, who also obtained patents, failed in their
undertakings, and resigned their privileges. It is a singular fact, that although
pit coal was known long before this period, and great quantities of it were

752 IRON.
exported to Holland and the Low Countries, where it was used in the Smith's
forge, and in other manufactories that require a strong continued heat; yet in
England the prejudice against its use in the manufacture of cast iron was so
inveterate, that when it was first proposed and attempted, every obstacle that
could be devised was thrown in its way, and none of the adventurers succeeded,
until the year 1619, when Dudley had a patent, and manufactured pig-iron in
a blast furnace, but produced only three tons in a week. He became, however,
the object of jealousy to the other manufacturers, who contrived to get his
patent limited from thirty-one to fourteen years, and his devoted works were
destroyed by a lawless mob, urged, it is supposed, by his rivals in business.
Soon after this, Captain Buck, Major Wildman, and some others, constructed
air furnaces in the forest of Dean, in which they placed large clay pots (similar
to those used in glass-houses) for containing the requisite preparations of ore
and charcoal, the flame of pit coal being employed for heating the furnaces;
and it was expected, that by tapping the pots below, the separated material
would flow out. But the heat was not sufficiently intense to produce an entire
separation of the metal, the pots cracked, and the scheme was abandoned. At
this time iron was advancing, in consequence of many of the iron works having
stopped for want of fuel. To those manufacturers, therefore, who could still
be furnished with a supply of wood, the manufacture was highly profitable,
and they obstinately opposed any new attempt by which the price of iron
might be diminished. It was not till impelled by necessity, arising from the
rapid decline of the annual growth of timber, that pit coal became an object
of universal estimation. In this feeling the Hon. Robert Boyle seems to have
participated, for in his Usefulness of Natural Philosophy, published in 1663, he
expresses a desire that some method could be found to make coke without the
use of pots employed for that purpose, in order that it might be applied to the
smelting of iron ores. Two years after this, Dudley (according to Mr. Gray)
wrote his Metallum Martis, in which he states, that his father and himself had
smelted iron with coke in large quantity, but that Oliver Cromwell, and some
favourites of his, wishing, on a renewal of the patent, to become partners,
and other political circumstances, had ruined the establishment, which seems
never to have been revived; for even so late as the year 1747, Mr. Mason
says, in the Philosophical Transactions, that several attempts have been made
to melt iron ore with pit coal, but he thinks it had not then succeeded any
where, as no account of its being practised had been published, but that
Mr. Ford did, however, then make pig iron, brittle or tough, as he pleased,
from iron and coal, both of which were procured on the same spot.
The brittle or inferior quality of English bar iron, made from coke at this
period, and the great expense of that which was made from charcoal, owing to
the increasing scarcity of wood, was most likely the cause of the great decline
in the home manufacture of iron which then took place; recourse having been
had to Sweden and Russia for a supply, the importation of which on a great scale
at this time commenced. The home manufacture was, however, again renewed
by the general introduction of the steam engine, which afforded the manufacturer
the command of a power he had before no conception of The small furnaces
supplied with air from bellows worked by oxen, horses, or men, were given up;
larger furnaces were introduced, and blowing machines, with an increase of
the column of air for exciting a more vivid combustion. The steam engine
was found particularly beneficial in those situations where there was an abun-
dance of minerals for making iron, but a deficiency of water to supply the
power. Experience also soon taught the manufacturer, that the produce of his
furnace could be increased by enlarging the diameter of his steam cylinder
and rendering the vacuum therein more perfect. It was soon found, that by
increasing these effects, a quantity of pig-iron could be produced from the coke
of pit coal, which would be attended with an adequate profit. Owing to the
small quantity of air necessary to ignite, and preserve the required heat in a
charcoal furnace, the manufacturers very cautiously enlarged the dimensions of
their blowing apparatus in applying it to coke; consequently much of the
advantage resulting from a great blast (which is now extended to about 4000
IRON. 75.3
cubic feet of air per minute) was lost. These difficulties were, however,
gradually surmounted, and it appears, that before the year 1760, the coke of
pit coal was in general use for blast furnaces. The iron trade assumed new
vigour, and made most rapid progress, as will appear from the following state-
ment of the total quantity of iron made in Great Britain between the years
1740 and 1827. Since the latter period, the manufacture and trade has been
on the increase, notwithstanding the price has advanced.
In the year 1740, 17,000 tons were made from 59 furnaces.
25 1788, 68,000 tons 3 y 121 ,
55 1796, 125,000 tons º-
5 3 1806, 250,000 tons 4-
,, 1820, 400,000 tons º – ,
,, 1827, 690,000 tons 5 y 284 ,
Of which latter quantity there were produced—
By Staffordshire . . . . 216,000 tons from 95 furnaces.
By Shropshire . . . . 78,000 53 31 5 y
By South Wales . . . 272,000 3 y 90 }}
By North Wales . . . 24,000 27 12 3 y
By Yorkshire . . . . 43,000 52 24 } }
By Derbyshire . . . . 20,500 5 3 14 } }
By Scotland . . . . . 36,500 5 y 18 2 3
Total . . . . 690,000 ,, 284 33
In the foregoing statement, several furnaces in Gloucestershire, Cheshire, and
other places are omitted, which will render the produce in round numbers
700,000 tons. About three-tenths of this quantity are of a quality suitable to
the foundry, which is all used in Great Britain and Ireland, with the exception
of a small quantity exported to France and America. The other seven-tenths
are made into bars, rods, sheets, wire, &c., of which a large quantity is exported
to all parts of the world. Having thus given a brief historical sketch of the
rise and progress of this interesting and useful manufacture, we proceed to lay
before our readers a concise account of the process by which iron is obtained
from its ores, and brought into a crude or pure state, adapted to the wants of
mechanics, or to the various uses to which it is applied.
Making of Coke.—The first operation is the preparation of the coal, to reduce
it to the state of coke, which is accomplished either in kilns, or in the open air.
The latter plan has been, and is still, the most extensively adopted; we shall
therefore describe it the first. An oblong square hearth is prepared, by heating
the earth to a firm flat surface, and paddling it over with clay. On this the
pieces of coal are piled up, inclining toward one another; and those of the
lower strata are set upon their acutest angle, so as to touch the ground with
the least surface possible. The piles are usually from 30 to 50 inches high,
from 9 to 16 feet broad, and contain from 40 to 100 tons of coal. A number
of vents are left, reaching from top to bottom, into which the burning fuel is
thrown; and they are then immediately closed with small pieces of coal beaten
hard in. Thus the kindled fire is forced to creep along the bottom, and when
that of all the vents is united, it rises gradually, and bursts out on every side at
once. If the coal contain pyrites, the combustion is allowed to continue a con-
siderable time after the disappearance of the smoke, to extricate the sulphur,
part of which will be found in flowers on the surface. If it contain none,
the fire is covered up soon after, the smoke disappears, beginning at the
bottom and proceeding gradually to the top. In 50, 60, or 70 hours, the
fire is in general completely covered with ashes of char, formerly made, and
in twelve or fourteen days the coke may be removed for use. In this way a
ton of ordinary bituminous coal commonly produces from 700 to 1,100 lbs of
coke.
Coke and Tar Works.-The annoyance attending this process by the evolution
of the immense quantities of smoke from the ignited matter, besides the entire
754 IRON,
waste of the volatile products, induced Lord Dundonald, many years since, to
carry into effect a plan for preventing the former, and saving the latter. One
of these tar works, as they were called, was erected at Mr. Wilkinson's great
works at Bradley, another at Tipton, and a third at the Level Colliery and
iron works upon Dudley-wood. Being erected in the vicinity of large iron
and coal works, the iron masters furnished the tar works with raw coal, and
received, in return the cokes produced by such coal, the proprietors being com-
pensated by the volatile products, viz. tar, pitch, varnish, and ammonia.
Coke Kilns.—The last described process of making cokes, is now being
superseded in many places, particularly in the neighbourhood of Sheffield, by
the employment of kilns made of bricks, of a hemispherical form, about ten
feet diameter at the base, and about two feet at the top, where a circular opening
is left for the introduction of the coal. The manner of working these ovens is
thus described by Mr. Parker:—“When these ovens are once heated, the work
goes on night and day without interruption, and without any further expense
of fuel. It is conducted thus: small refuse coal is thrown in at the circular
opening at the top, sufficient to fill the oven up to the springing of the arch;
it is then levelled with an iron rake, and the doorway on the side built up with
loose bricks. The heat acquired by the oven in the former operation is always
sufficient of itself to light up the new charge, the combustion of which is
accelerated by the atmospheric air that rushes in through the joints of the
loose bricks in the doorway. In two or three hours the combustion gets to such
a height, that they find it necessary to check the influx of the air; the door-
way is therefore now plastered up with a mixture of wet soil and sand, except
the top row of bricks, which is left unplastered all might. Next morning, when
the charge has been in twenty-four hours, this is completely closed also, but
the chimney remains open till the flame is gone, which is generally quite off in
twelve hours more. A few loose stones are then laid over the aperture, and

--" --- --->4.
closely covered up with a thick bed of sand or earth. All connexion with the
atmosphere is now cut off, and in this situation the whole remains for twelve
hours to complete the operation. The doorway is then opened, and the cokes
are raked into iron wheel barrows, to be carted away. The whole operation
takes up forty-eight hours, and as soon as the cokes are removed, the ovens are
again filled with coal for another burning. About two tons of coals are put in
for each charge, and the cokes produced are ponderous, extremely hard, of a
light grey colour, and shine with metallic lustre; they acquire in the furnaces
an intense heat, and will sustain a great burthen of iron-stone and other
materials.” When coke is required to be more of the nature of charcoal, the
process is conducted in a different manner. The small coal is thrown into a
large receptacle, similar to a baker's oven, previously brought to a red heat.
Here the door is constantly open, and the heat of the oven is sufficient to
dissipate all the bitumen of the coals, the disengagement of which is promoted
by frequently stirring it with a long rake. The coke from the ovens, though
made from the same kind of coal, is very different from that produced by the
former operation, this being intensely black, very porous, and as light as pumice
stone. Under the article LIME-BURNING, a drawing and description of a patent
oven for making coke is given, in which the latter operation is made subservient
to the first. The mechanical arrangement and process therein exhibited, may be
advantageously applied to the roasting of ores instead of lime, and the coke
required for the smelting furnace might be made at the same time. As we
have extended our observations on the making of coke from pit coal to a
length which some of our readers may probably consider to be unsuited to its
real importance, we would observe, in the language of Dr. Colquhoun, that the
substance “has been the means of advancing the manufacture itself in this
country, to an extent which is unparalleled in the history of any other country or
nation. It has now been ascertained, by long experience, that there is no other
fuel which is so well fitted at once to supply the heat of the furnace, and, at the
same time, to endure the powerful blast which is incessantly forced upon it.
It may now be said to be essential to our iron manufacture, which would,
indeed, be almost annihilated were the supply of it withdrawn.” Without it
IRON. 755
we should be compelled to lay under wood immense tracts of what are now
fertile corn fields, in order to supply, at an enormous expense, a much more
imperfect fuel for the furnace. But the treasure of it seems to be inexhaustible,
and not less so the metal for which it is required, as will be seen upon reference
to the article CoAL, wherein we have given a section of Bradley mine, and the
arrangement of the numerous distinct strata cut through to arrive at the coal,
amongst which there occurs from thirty to forty feet thickness of iron-stone,
before the principal bed of coal is arrived at.
Roasting Iron-stone.—The ores of iron require different treatment in the
smelting process, according to the nature and extent of the heterogeneous
matter with which the metal is combined. In all ores the iron is in the state
of an oxide, and would require a strong heat in contact with combustible
matter for their reduction. In most species, the oxide of iron is combined
with a considerable proportion of earthy or stony matter, and they are thence
denominated iron-stones. But besides the earthy matter and oxygen, many of
these contain sulphur, arsenic, and manganese; and it is necessary that these
should be extricated previously to melting, which is effected by calcination, called
roasting. This is usually done by stratifying the ore, broken into small pieces,
with small or refuse pit coal, and burning it in great heaps, either in the open
air, or in a kiln; which dissipates the sulphureous, arsenical, and other volatile
matters, leaving behind the earth and oxide of iron, which are then easily
broken into convenient fragments for melting.
Teague's Patent Roasting Furnaces.— Mr.
Teague, of the Park End Iron Works, near
Calford, in Gloucestershire, took out a patent
in 1832, for improvements in smelting, in
which he proposes to economise the process of
roasting the ore, both as respects the labour
and the fuel. Instead of making the calcina-
tion a distinct process, conducted in another
part of the works, he combines the operations
of roasting and smelting, which go on simul-
taneously in the same furnace. For this pur-
pose he constructs around the chimney shaft,
near to the top or tunnel-head of an ordinary
smelting furnace, a series of four or more
small reverberatory furnaces or ovens, each
provided with a chimney, a damper at top, and a
lateral door, which opens externally. Through
these doors the ores to be roasted are in-
troduced, and deposited upon iron plates,
which form the bottoms, and incline down-
wards towards the shaft of the smelting fur-
nace. ' The ascending body of flame from the
latter, when at work, is prevented from passing
out vertically, as usual, by means of a valve
or trap door, which closes the orifice, and the
small chimneys to the surrounding reverbera-
tory roasting furnaces being opened, causes
the flame and heated matters to pass through
these, and in their progress to impinge upon
the ore, and deprive it of its volatile com-
binations, When the ores have been thus
sufficiently operated upon, they are thrust
forward by a proper tool into the body of the
smelting furnace ; and whilst the roasting
furnaces are being recharged, the valve or
trap to the smelting shaft is opened, that the
flames may take that course instead. Thus
it would appear that a considerable saving

7.56 1RON.
of labour is effected, and that all the fuel employed in roasting by the ordinary
process is likewise saved, as the flame which usually passes out of the tunnel-
head to waste in the air, is made to calcine the ore, and this being dis-
charged into the blast furnace at the high temperature it had acquired in the
oven, the subsequent fusion of it is greatly accelerated. In Fig. 1, on the
preceding page, is given a vertical section of one of these roasting ovens, in
connexion with the tunnel-head. a a represents a portion of the tunnel-head,
or upper end of the blast furnace, provided with a door or valve b, resting on
a ledge at c ; d is one of the four ovens; e the iron plate that contains the ore
or “mine,” supplied through a doorway at f; g the oven chimney, with its
damper h. Fig. 2 exhibits, on a smaller scale, a plan of the whole building,
taken just above the oven plates, as designated by the four letters e : the fifth
compartment i of the pentagon being for supplying the fuel and fluxes into
the tunnel a, into which all of the compartments directly lead; each of these
are closed externally by massive iron doors, suspended to stout iron lever beams
to the opposite ends of which are hung counterbalancing weights, that enable
the workmen to move them with facility. The dotted rectangle upon the plan
is designed to explain the precise nature of the sectional view given in Fig. 1.
Jefferies' Coke and Iron Ore Furnace.—A patent for economizing the process
of roasting ores was, however, taken out prior to the last-mentioned, by Mr. W.
Jefferies, of Ratcliff, which was specified in August 1827. By this plan the
roasting of the ore and the forming of the coke are performed together in one
furnace; the process is thus described in the Journal of Patent Inventions,
Vol. II. p. 66: “The ore is first broken by stampers, or crushed by rollers,
until it is reduced to such fragments as will pass through a sieve of eight or ten
holes to the square inch. After which, instead of introducing the pulverized
ore into a roasting oven or furnace, it is incorporated with a sufficient quantity
of small coal, and the mixture put into a coke oven, previously heated in the
usual way. Herein the ore is calcined by the heat of the coal, the latter being
thereby converted into coke; for this purpose the door of the oven is left open
until all the flame has passed off, in the ordinary manner, when the door is to
be closed, and all access of air prevented. After this the charge is to be with-
drawn, as if it were coke merely, and, when cooled, broken down into masses
of a proper size for the smelting furnace, into which it is thrown ; the metal is
here "smelted out’ from the coke with which it was combined; the coke serving
as the fuel to fuse and extract it.”
Fluates.—The coke and iron-stone having been duly prepared, the next consider-
ation is the nature and extent of the flux required to separate the metal by fusion
from those of its combinations which the previous process was inadequate to
perform. These differ in every degree and form, according to the nature of the
ore, and as their consideration at length would occupy a greater space than the
assigned limits of this work will afford, we purpose availing ourselves of a few
extracts from the valuable papers by Mr. David Mushet, inserted in Tillock's
Philosophical Magazine; and must refer those of our readers who may desire
more information to the original source for it. “To deprive an ore of its iron”
(says Mr. Mushet) “so that no portion of it shall escape in the scoriae
unrevived, two things are indispensable. First, the metal contained in the ore
must be presented to a portion of fuel sufficient to take up the oxygen of the
metal. Second, as this revivification goes on in the manner of a metallic per-
spiration upon the softened surface of the ore, another agent ought to be present
to facilitate the separation by uniting with the earthy parts of the ore, forming
a thinly divided lava, no longer capable of retaining the globules of metal, or
of preventing the congenial affinity of the carbonic principle from taking full
effect for the improvement of the quality of the iron.”—“Experience has
shown that an excess of any particular earth may be corrected by applying one
opposite in its effects; and that the addition of lime, in various proportions, is
found in most cases to answer the desired end.”—“If the various classes of
iron ore are fused in contact with charcoal, without the addition of a flux or
solvent, the result is, from calcareous iron-stone, a larger portion of iron propor-
tioned to the intrinsic richness of the ore, than from argillaceous iron-stone;
IRON. 757
and from the latter a larger produce of iron, than from an ore whose chief
mixture was silex; the scoriae produced from the respective operations always
demonstrate, from the colour and opacity, the probable quantity of iron which
still remains to be taken up.” There are some calcareous iron-stones which
contain lime almost sufficient to form the necessary scoriae, the colour of which,
when freed from the metal, possesses a considerable degree of transparency.
When a number of these stones are used in the blast furnace, a much less
quantity of calcareous earths are necessary. . It sometimes happens at iron
works, whose chief supply is derived from a calcareous field of iron-stone, that
by using a great proportion of an individual ore, surcharged with lime, the
operations of the furnace are obstructed, and consequences entailed fatal to the
interest of the manufacturer. From an excess of pure calcareous earth being
present in the furnace, the scoriae, thick and curdled, becomes attached to the
sides and bottom of the furnace; the quantity hourly increases, till it has
accumulated to such a degree as to intercept the ascent of the blast, and the
descent of the materials. The remedy suggested by Mr. Mushet for these
inconveniences, is, reducing the quantity of lime direct, or by an admixture
of clay or sand, whether combined with iron or not. An excess of clay in the
argillaceous ores has the same prejudicial effects which have led to their rejection,
though it has been owing to improper application. The fusibility of lime and
clay individually is much facilitated by the addition of sand. In all cases
where these earths exist in excess in the ores, they ought either to be combined
in the blast furnace with siliceous iron-stone, or treated with a lime-stone con-
taining a considerable portion of sand. When a scarcity of lime exists in the
blast furnace, and a superior quantity of clay and silex is combined with the
iron-stones, the lava will flow from the furnace comparatively cold, tenaceous,
and of a brown or pale dirty green colour, containing iron; when the mixture
is just, the colour of the scoriae is pure white, enamelled with a variety of blue
shades, waving, circular, or formed in straight delicate lines, arising from a
peculiar existing modification of a minute portion of the metal. Where nature
has bestowed mixtures productive of every quality of crude iron, the proper
management of ores would become simple and easy: just combinations super-
sede the necessity of changing the quality of the lime-stone added for a flux,
or of having recourse to various qualities of it, in order to assist or correct the
deficiency of the native mixture. Wherever the ores are of a structure thus
deficient, it then becomes the province of the manufacturer to ascertain the
mixture of the individual ores which compose his supply, and to restore that
equilibrium of parts by the proper application of superadded earths which
experiment and observation have proved to determine a certain quality of iron.
Many years ago, Messrs. Hill and Co. of the Plymouth works near Merthyr,
took out a patent for the use of the “cinder" produced in the refining and
puddling operations, as a substitute for a portion of mine in the smelting pro-
cess. This cinder or scoriae is an oxide of iron combined with but little foreign
matter, and usually contains from 50 to 70 per cent. of metal. All previous
attempts to smelt it economically had failed. Messrs. Hill and Co. mixed with
it such a portion of argillaceous matter as to assimilate it to the natural ore of
their district, and by this combination succeeded in its perfect reduction. The
patent was soon after invaded; and, upon an action being brought for infringe-
ment of right, the defendants proved a prior application of the process. The
patent was thereby quashed, and the iron masters, in consequence, generally
adopted the process; but, from injudicious management, much bad iron was
made, which got it into disrepute. With proper care, and in small proportion,
the cinder is now used advantageously at most of the iron works, in the making
of forge-pigs, under the subsequent process of puddling. It is usual, in most
furnaces, to make the coke always a fixed quantity, and to proportion the iron-
stone and the lime or other flux, to the quantity of iron to be made, and the
working order of the furnace; and in proportion to the latter additions, the
furnace is said to carry a greater or less burthen. Some furnaces carry so
little burthen as to produce only about 13 tons per week, while there are others
which yield as much as 70 tons per week. In these latter, the ore is in much
O D
758 IRON.
greater proportion to the coke than the former, but the product is inferior.
The burthen is varied according as the iron is required to possess more or less
carbon; thus in making No. 1, or best iron, (which contains the greatest pro-
portion of carbon, the burthen must be considerably less than that required to
make less carburetted iron, or what is called white-iron, or forge-pig. A
general idea of the proportions of the materials from an argillaceous ore, con-
taining about 27 per cent, of iron, with a strong carbonaceous coal, and a good
limestone, consisting of shells, is afforded by the operation of a furnace under
Mr. Mushet's direction. The furnace works with a bright tuyere, and receives
from the blast about 2500 cubic feet of air per minute, through a circular
aperture 2# inches in diameter. The quantity of calcined ore for the manu-
facture of good melting iron is upon a par with the coke; and forge-pig, or the
least carburetted variety, six of coke to seven of ore. The lime-stone, unburnt,
under the same circumstances, is to coke as 4 to 11 ; and for melting metal,
retains a similar ratio. -
Smelting Furnace.—The external figure of a blast furnace is that of a trun-
cated pyramid, while its interior form has been very aptly compared to that of
a decanter, supported upon a funnel. In the subordinate details of their con-
struction, there is much variation by different iron masters, which, however,
probably does not essentially affect the results. In the annexed sectional
representation of one of these great laboratories, we have not selected one of
*
2
Fig. 1.
4.
zº,
t
t—º-
*F
*
ſ
ºil
Pig. 2. 2][][2][...] §3 $
Fig. 2 #H#H §§§
W.
N
N
the latest mould, but one that was described and found to be very efficient by that
great master in metallurgic operations, Mr. David Mushet; since which, we
believe there have been no improvements of essential importance, except in the
blowing machinery, which we shall duly notice, a is the regulating cylinder, 8





HRON. 7.59
feet in diameter, and 8 feet high; b the floating piston, loaded with weights pro-
portionate to the power of the machine; c the valve by which the air is passed
from the pumping cylinder into the regulator; d the aperture by which the blast
is forced into the furnace; diameter of the pipes, 18 inches; e the blowing or
pumping cylinder, six feet diameter, 9 feet high, 7 feet stroke; f its piston,
with a view of one of its several valves; g solid masonry, on which the regu-
lating cylinder rests, and to which the flanch and tilts of the blowing cylinder
are attached. h the safety-valve or cock, by the simple turning of which, the
blast may be admitted to, or shut off from the furnace, and passed off to a
collateral tube in the opposite side. i the tuyere, by which the blast enters the
furnace. The end of the tapered pipe, which approaches the tuyere, receives
small pipes of various diameters, from 2 to 3 inches, called nose pipes, which
are applied at pleasure, according to the strength of the blast required. k is
the bottom of the hearth, 2 feet square; l the top of the hearth, 2 feet 6 inches
square; k l the height of the hearth, 6 feet 6 inches; l is also the bottom of
the boshes, which here terminate, of the same size as the top of the hearth,
only the former are round and the latter are square. m the top of the boshes,
12 feet in diameter, and 8 feet high; n the top of the furnace, 3 feet diameter,
at which the materials are charged; m n the internal cavity of the furnace of
the top of the boshes upwards, 30 feet high. nk, total height of the internal
parts of the furnace, 44% feet; o o the lining, which is built with fire bricks,
13 inches long by 3 thick, in the nicest manner; pp a vacancy left all round the
outside of the first lining, 3 inches wide, which is rammed full of coke dust, this
space being left for the expansion of the materials by heat; q q a second lining,
similar to the first; r a cast iron lintel, in which the bottom of the arch r s is
supported—this arch is 14 feet high on the outside, and 18 feet wide; v v the
extremes of the hearth, 10 feet square. Fig. 2 represents a plan of the foun-
dation of the furnace; a a are the bottom stones of the hearth; b stratum of
bedding sand; c c passages for the escape of vapour; d d pillars of brick; these
parts, in the dotted elevation, are indicated by similar letters of reference.
The subjoined, Fig. 3, affords an horizontal section of Fig. 3.
the diameter of the boshes, the linings and vacancy
being indicated by similar letters of reference to those
in the elevation. Fig. 4 exhibits a vertical side section
of the hearth and boshes, showing the tymp and dam-
stones, and the tymp and dam-plates, a the tymp-
stone ; b the tymp-plate, wedged firmly to the stone, to
hold it in case of splitting by the heat; c, dam-stone,
which occupies the whole breadth of the bottom of the
hearth, excepting about six inches, which, when the i
furnace is at work, is filled every cast with strong sand. ;
This stone is surmounted by an iron plate of great
thickness, called the dam-plate, the top of which is
about 3 inches below the tuyere hole. The space be-
tween the bottom of the tymp and the dotted line is
rammed full of strong sand or fine clay, called the tymp
stopping, which prevents any part of the blast being
wasted. The square of the base of this blast fur-
nace is 38 feet; the height from the false bottom to the top of the crater,
55 feet.
Mode of working furnace.—When the furnace is finished, the bottom and
sides of it for 2 feet up the square funnel, receive a lining of common bricks
upon edge, to prevent the stone from shivering or mouldering when the fire
comes in contact with it. On the front of the furnace is erected a temporary
fire-place, about 4 feet long, into the bottom of which are laid corresponding
bars. The side walls are made so high as to reach the under surface of the
tymp-stone. A fire being kindled upon the bars, the whole cavity of the fur-
nace serves as a chimney; the draught and heat is therefore considerable. In
the course of three weeks, the furnace is freed from damp, and ready to
receive the materials; the fire-place is then removed, but the interior brick


760 IRON.
lining remains till the operation of blowing commences. Some loose fuel is
then thrown upon the bottom of the furnace, and a few baskets of coke, which
are allowed to become thoroughly ignited before more are added, and the fur-
nace is then gradually filled. The furnace represented is capable of holding
99,000 lbs. of coke, equivalent to 198,000lbs. of coal. This quantity of mate-
rials is continually burning for several years together, without intermission 1 A
renewal of the total quantity occurs about every third day. There are, neverthe-
less, still larger furnaces in Wales. The first charges which a furnace receives
contain but a small proportion of iron-stone compared to the weight of the
coke, which is afterwards increased to a full burden. The descent of the bur-
den is facilitated by opening the furnace below, two or three times a day, throwing
out the cold cinders, and admitting, for an hour at a time, a fresh body of air.
This operation is repeated till the approach of the iron-stone and cinder, which is
always announced by a partial fusion, and the dropping of lava through the
iron bars, introduced to support the incumbent materials while those in the
bottom are carried away. The filling above is regularly continued; and when
the furnace at the top has acquired a considerable degree of heat, it is then
judged time to introduce the blast; the preparations of which are the follow-
ing:—The dam-stone is laid in its place firmly imbedded on fire-clay; the
dam-plate is again imbedded in this with the same cement, and is subject to the
same inclination. On the top of this plate is a slight depression, of a curved
form, towards that side farthest from the blast, for the purpose of concentrating
the scoriae, and allowing it to flow off in a continued stream, as it tends to sur-
mount the level of the dam. From this notch to the level of the floor a decli-
vity of brick-work is erected, down which the scoriae of the furnace flows in
large quantities. The opening betwixt the dam and side walls of the furnace,
called the fauld, is then built up with sand, the loose bricks are removed, and
the furnace bottom is covered with powdered lime or charcoal dust. The
ignited cokes are now allowed to fall down, and are brought forward with
Iron bars, nearly to a level with the dam. The space between the surface of
the cokes and the bottom of the tymp-plate is next rammed hard with strong
binding sands; and these cokes, which are exposed on the outside, are covered
with coke dust. These precautions being taken, the tuyere hole is then
opened and lined with a soft mixture of clay and loam; the blast is commonly in-
troduced into the furnace, at first with a small discharging pipe, which is afterwards
increased as occasion may require. In two hours after blowing, a considerable
quantity of lava is accumulated; iron bars are then introduced, and perforations
made in the compressed matter at the bottom of the furnace; the lava is ad-
mitted to all parts of the hearth, and soon thoroughly heats and glazes the sur-
faces of the fire-stone. Shortly after this it rises to a level with the notch in the
dam-plate, and by its own accumulation, together with the forcible action of the
blast, it flows over. Its colour is at first black; its fracture dense, and very
ponderous; the form it assumes in running off is flat and branched, sometimes
in long streams, and at other times less extensive. If the preparation has been
well conducted, the colour of the cinder soon changes to white; and the metal,
which is in the state of an oxide formerly coloured, will be left in a disengaged
state in the furnace. When the metal has risen to nearly a level with the
dam, it is then let out by cutting away the hardened loom of the fauld, and
conveyed by a channel made in sand to its proper destination; the principal
channel, or runner, is called the sow, the lateral moulds are called the pigs;
hence the name of the raw commercial article, “pig-iron,” of which many
hundred thousands of tons are annually made.
Phenomena attending the production of the different qualities of Pig-metal.—
When fine (No. 1,) or super-carbonated crude iron is run from the furnace, the
stream of metal, as it issues from the fauld, throws off an infinite number of
brilliant sparkles of carbon. The surface is covered with a fluid pellicle of
carburet of iron, which, as it flows, rears itself up in the most delicate folds;
at first the fluid metal appears like a dense ponderous stream, but as the colla-
teral moulds become filled, it exhibits a general rapid motion, from the surface
of the pigs to the centre of many points. Millions of the finest undulations
IRON. 761
move upon each mould, displaying the greatest nicety and rapidity of movement,
conjoined with an uncommonly beautiful variegation of colour, which language
is inadequate justly to describe. . Such metal, in quantity, will remain fluid for
twenty minutes after it has run from the furnace, and, when cold, will have its
surface covered with beautiful carburet of iron, already mentioned, of an
uncommonly rich and beautiful appearance. When the surface of the metal
is not carburetted, it is smooth, like forged iron, and always convex. In this
state iron is too rich for melting without the addition of coarse metal, and is
unfit to be used in a cupola furnace for making fine castings, where thinness
and a good skin are requisite.
No. 4, or oxygenated crude iron, when issuing from the blast furnace, throws
off from all parts of the fluid surface a vast number of metallic sparks, and,
while running, it is covered with waving flakes of an obscure smoky flame,
accompanied with a hissing noise. This is a slight sketch of the appearances
of the two extreme qualities of crude iron, when in a state of fusion. There
still remain two intermediate stages of quality to be described; these are,
carbonated, and carbo-oxygenated iron, that is, No. 2 and No. 3 of the
manufacturers. --
No. 2, or carbonated iron, exhibits, like No. 1, a beautiful appearance in the
runner and pig. The breakings of the fluid, in general, are less fine, the
agitation less delicate, though the division of the fluid is equal, if not beyond,
that of the other.
No. 3, or carbo-oxygenated iron, runs smoothly, without any great degree of
ebullition, or disengagement of metallic sparks. The partings upon its surface
are longer, and at greater distances from each other than in the former varieties;
the shape they assume is either elliptical, circular, or curved. In cooling, this
metal acquires a considerable portion of oxide. An infallible criterion of the
quality of the iron in the furnace is afforded by the colour of the scoriae upon
the working bars, which are from time to time inserted to keep the furnace free
from lumps, and to bring forward the scoriae. When No. 1, or super-carbonated
iron, is on the hearth, the vitriol crust upon the bars will be of a black colour
and smooth surface, fully covered with large and brilliant plates of plumbago.
As the quality of the metal approaches to No. 2, (carbonated,) the carburet
upon the scoriae decreases both in point of quantity and size. When carbo-
oxygenated (No. 3) is in the furnace, the working bars are always coated with
a lighter coloured scoriae than when the former varieties exist; a speck of
plumbago is now only found here and there; and when the quality of the metal
is oxygenated (No. 4), not only have the plates of carburet disappeared, but also
the crally colour on the external surface of the scoriae. It may perhaps be
proper here to mention, that although for convenience the manufacturer has,
from a just estimation of the value of the metal in a subsequent manufacture,
affixed certain numbers for determinate qualities of iron, yet it is difficult to
say at what degree of saturation of carbon each respective term commences;
suffice it then to say, that the two alterative principles, oxygen and carbon, form
two distinct classes—that in which oxygen predominates, and that in which
carbon predominates.
Mechanical arrangements for supplying the tunnel-head with the materials for
fusion.—The mode of supplying the lime, coke, iron-stone, &c. to the crater, or
tunnel-head of the furnace, was formerly by men carrying them in baskets up
an inclined plane or bridge. Subsequently small waggons or corves were em-
ployed to take the materials up an inclined railway to the crater, by means
of chains connected to the waggons, and passing round a drum or rigger,
actuated by the steam engine, or other prime mover. In some instances the
weight of a bucket of water descending into a pit was employed as the moving
force to draw the loaded corve up to the top of the furnace, or hopper leading
into it; where the corve, by being provided with a sliding bottom, to which was
fixed a projecting bar, discharged its contents, by the bar coming against an
obstruction, which pushed the bottom away, when over the discharging hole.
The bucket also, on reaching the bottom of the pit, was discharged of its water,
through a valve in its bottom being opened by coming in contact with a
762 | RON.
projecting pin at the bottom of the pit. The motion was then reversed by the
superior weight of the empty waggon, causing it to descend the inclined plane,
and raise up the empty bucket for a renewal of the operation, by refilling the
vessels, one with the mineral, and the other with the water. In some situations
the mode of raising the materials is by an endless chain passing round two
riggers, one at each extremity of the inclined plane, the chain carrying two
corves or buckets, one of which is being filled below whilst the other is being
discharged above, in continuous succession ; in a similar way to the scoops in
dredging and excavating machines, described under their initial letters.
Welsh Smelting Purnaces.—In South Wales and other mountainous districts
they usually contrive to build their blast furnaces beside cliffs or steep preci-
pices, which are sometimes walled up artificially to render them perpendicular,
so that the tunnel-heads of the furnaces shall be upon a level or somewhat
lower plane than the contiguous high ground, from which a bridge is thrown on
to the top of the solid masonry, after the manner expressed in the subjoined
cut. This cut also gives the external form of the fur-
nace described at page 758, with this difference merely, Ess
that instead of the open crater or tunnel-head, this has #:
a vertical cylindrical chimney of the same internal area
as the upper orifice built over it; on one side of which
there is a doorway for charging the furnace with the
mine and other materials. A parapet wall or iron
fence surrounds the upper edge of the square tower. Hº
The dotted lines in the figure indicate the form of the #
interior of the furnace. The coke-hearths and the
mine-kilns, and all other supplies to the furnace, are F-4
situated on the high ground, so that they can at once be shot across the bridge
into the tunnel-head. Various buildings, including the “cast-house,” where the
metal is run into pigs (or other forms to patterns as may be required) are situated
on the lower level, and are covered with roofs.
Anthracite used in Smelting.—Before closing our account of the smelting
department of the iron manufacture, we think it right to call the attention of
those who are interested in the iron trade to the consideration of the practica-
bility of employing anthracite, or stone coal, in the process of smelting. In
several parts of Great Britain and Ireland, but particularly in Scuth Wales,
there are many thousands of acres of iron-stone near the surface, with a vast
abundance of anthracite coal, lying in contiguous strata. This coal, notwith-
standing it consists almost entirely of carbon, has been alleged, and is
generally believed, to be incapable of smelting iron; and as there are in some
districts (that of Llanelly, for instance,) no bituminous coal sufficiently near to
these valuable beds of iron-stone, they remain unworked, under the presumption
that they cannot be worked with profit, owing to those circumstances. Whether
this prejudice is well or ill-founded, is a question that we cannot take upon
ourselves to solve; but we will place before the reader a few facts that appear
to bear directly upon the question, and leave the solution to those who are
more practically conversant with the subject.
In several parts of the United States of America, where (as in South Wales)
iron-stones and anthracite are plentiful, but bituminous coal wanting, recent
attempts have been made to smelt the iron with anthracite alone; and all the
reports that have reached us on that subject agree in stating that success has
attended those attempts.
Malin's Furnace for Smelting Iron with Anthracite Coal—Mr. Joshua Malin,
of Lebanon, in Pennsylvania, has described his furnace for this purpose in the
Franklin Journal. It is very similar to our common blast furnaces, the cru-
cibles and hearth alone differing materially. Mr. Malin's crucible, instead of
being square is round; anthracite coal being so much more dense than coke or
charcoal, its weight causes it to descend in the corners or angles of a square
hearth, where, being screened from the intense blast which is required, and
carrying with it a portion of the unmelted ore, it mixes with, and chills a
quantity of the fused ore and metal, which stops the operation of the furnace.


IRON. 763
tº)
For the smelting by means of anthracite, Mr. Malin states, that the blast
must be introduced under a pressure of at least two and a half pounds to the
circular inch ; and the quantity required for a common sized furnace will not be
less than 28,000 cubic feet per minute, or 7 cubic feet per minute for every
circular inch in the area of the hearth at the tuyere. The hearth of the furnace
in which Mr. Malin made his experiments, was only 11 inches in diameter at
the tuyeres, the blast being introduced as represented in the subjoined plan.
Mr. Malin had the diameter increased to 14 inches, and found that the blast
which he had at his command would not enable him to go beyond that point,
as, when he attempted it, the scoriae and metal chilled, and formed a tube from
the tuyere a part of the way across the hearth. Fig. 1 exhibits a vertical sec-
tion, and Fig. 2 an horizontal section drawn to a scale of an eighth of an inch
to the foot; the letters of reference in each figure that are the same indicate
Fig. 1. Fig. 2.
§: § ğı
§§ sº - § Sss:
º sis
§§ § §
§§ - jſ Jº §§§
§§§
§§
|S
§
§
$
º
corresponding parts. a is the crucible, being a part of what is commonly called
the hearth of the furnace; b are the boshes, or that part where the metal passes
from the solid to the fluid state as it descends; c is the bottom stone of the hearth,
bedded in sand, and supporting the crucible and boshes; d is the dam-stone;
ee the blast pipes; ff inner walls of the furnace of fire-brick, around which
is a space from 4 to 6 inches wide, filled with soft sand-stone; h tymp-plate;
i i lintels of cast-iron to support the inner walls over the tuyere and tymp-
arches; k k tuyere arches; l part where the metal flows out; m tymp arch; n
the tymp-stone, forming a part of the crucible, and supporting a part of the
boshes.
The prejudices in America against the use of anthracite were as strong as
they are here; but there they are now being rapidly dissipated by an irre-
pressible spirit of enterprise, guided by scientific intelligence; whilst we, out of
reverence to the ignorance of our forefathers, adhere to and cherish them. In
America anthracite was at first introduced into the parlour grates, where, having
gained a triumph, it descended into the kitchens, in spite of the vehement pro-
testations of the ministers of the victualling department; having, however,
here demonstrated its superiority over all other kinds of fuel, it next presents itself
to the notice of stea-furnace men and the iron masters; these, however, asserted
that there was something in its very nature which, in their occupations, forbade
its use; and they were so obdurate, Dr. Jones informs us, that “you might
as well have attempted to convince them that it was fit to be made into candles,





























764 IRON.
as that it might be employed for their purposes if their furnaces were suitably
constructed, and the fuel properly managed.” “It appears likely, however,” our
scientific historian continues, “that it will soon assert its claims to superior
excellence in these applications also, and triumph over the prejudices of the
managers of furnaces, as it has over those of the householder, the cook, and the
blacksmith.”
Improved Blowing Machinery—In continuing our account of the process of
obtaining iron in the smelting furnace, we omitted to notice that the blowing
apparatus delineated in connexion therewith, has, in a great measure, been
superseded by improved mechanism of that kind. The pumping cylinder, by
an arrangement of valves well understood, is made to draw air on both sides of
the piston, so that whilst the air enters on one side it is forced out on the other
into the regulating vessel, from whence it is usually conducted into the fur-
nace by two or three distinct pipes and tuyeres. But a most ingenious arrange-
ment of blowing cylinders was invented by Mr. Paterson, of Lanark, which is
described and figured in the article BLowING MACHINEs, wherein several others
are given. Water bellows have been extensively employed, but the objection
to these has been the humidity which the air acquired by the spray; to remedy
this defect, the air is forced into a dry regulator, which is simply a large air-
tight metal box, about 10 feet square and 40 feet long. At Bradley iron works
they have a regulating cylinder of still greater dimensions. The uniform elas-
ticity which the air acquires in these great chambers causes it to issue in a
constant equalized blast.
The blowing of heated air has recently been introduced at several foundries,
and likewise at the Clyde iron works. It is the invention of Mr. J. B. Neilson,
of Glasgow, whose patent was enrolled in March, 1829, and is designated an
improved application of air to produce heat in fires, forges, and furnaces, where
bellows or other blowing apparatus is required. He proposes that the air sup-
plied by any kind of machine shall, before it enters the furnace or cupola, be
made to pass through an air-vessel heated to very high temperature, a red heat
if possible, by which means a current of hot air will be thrown on the fire
instead of the cold current usually employed. It is recommended that the air
vessel be surrounded with some non-conducting substance, and imbedded in
masonry. The capacity of this vessel for a smith's forge he recommends to be
about 1,200 cubic inches, and for a cupola or blast furnace, about 10,000 cubic
inches. It was much doubted whether the increased temperature of the fire
thus blown would produce advantages equivalent to the expense of constructing
the air vessel and keeping it at the requisite heat; and as respects the smelting
of iron in particular, the theory seemed opposed to the well-known fact that a
much larger quantity of iron is yielded by the blast furnaces in the winter
season, or when the air is cold, than during the summer season, when the air is
warm. The experiments at the Clyde iron works, have however been reported
most favourably of, and the saving of coal attending it is so great, that it was
stated, in the Glasgow Chronicle, to be calculated to accomplish a saving in the
consumption of this island to the amount of 200,000l. annually. At the
Clyde iron works the air was heated to 2200 Fahr. before it was discharged
into the furnace; an effect which was produced by the expenditure of only one-
eleventh part of the cost of fuel it takes to heat it to the same temperature in
the blast furnace, which may be accounted for by the circumstance that Mr.
Neilson's air vessel is heated by coals, while the blast furnace is heated by coke.
Should further experience in this invention confirm the views of the patentee,
it may be regarded as a valuable improvement in metallurgic operations.
Refining Furnace. — The refining of pig-metal is a modern intermediate
process of conversion, which the experience of our iron masters has led them
to believe is the best economy in the preparation of the metal for being subse-
quently rendered malleable in the puddling furnace, although it is well
understood to be unnecessary to the production of wrought iron. The furnaces
employed for this purpose are small buildings, termed refineries; a vertical
section of one of them is given in the cut on the next page. a is a thick cast-iron
trough, having three of its sides made double, with a hollow space between,
around which water is caused to flow
from an external cistern b, the cool-
ing effect of the fluid serving to
prevent the fusion or other injury
of the metal sides of the furnace by
the intense heat; at c (in a line) are
two pipes, through which air is
forced from a blowing machine upon
the materials in the trough ; these
pipes are kept cool by a constant
stream of water always flowing over
them, brought on by small pipes d,
regulated by cocks. The bottom of
the furnace is of brick, on which
the fuel is laid, and over it the pigs
%
º - i
to be º . . is bº ºil
12 feet high, and the front, which is left open, has a projecting roof to cover
the workmen who attend to it. In Wales it is usual to make these furnaces
what is termed double; that is, the fire is somewhat larger though single, but
the blast is double, there being usually three pipes and tuyeres on each of two
opposite sides of the furnace; each of the pipes are generally about an inch in
diameter, and supplied with a blast equal to about 2 or 23 lbs. pressure upon
the square inch. The pigs are kept in a state of fusion for some time, exposed
to an intense heat from the powerful blast just mentioned, which drives off a
portion off the carbon united to the metal. When the operation, which usually
occupies two hours, is deemed to be complete, a hole in front of the hearth is
tapped, through which the liquid metal flows into a very thick oblong flat mould
of cast-iron, placed over a cistern of water; this causes the metal to be rapidly
chilled, which is thus brought into a cake about 2 feet broad and 20 feet long.
This plate of metal is extremely brittle, and presents on its fracture a silvery
whiteness: it weighs about a ton. In some refineries the furnace is lined with
firebricks or stones, without water running round it, and the refined metal is
cast upon sand in shallow moulds or depressions, and water is then thrown upon
the metal to cool it quickly. As inattention or neglect on the part of the refiner
would be productive of serious loss to the iron master, he is always paid
according to the metal produced. Great experience and practical skill are requi-
site qualities in a refiner; his occupation is one of great personal exertion, and he
is exposed to an intense fire, that no one unaccustomed to it could even approach.
He puts the charge of pigs upon the fire, attends to the progress of the melting,
supplies the fire from time to time with coke, frequently stirring it up to equalize
the heat; sees that the tuyeres are in good order, and that the water circulates
uninterruptedly; runs out the metal when it is ready; he removes the plate
from its mould when it has a little cooled, by means of a lever, on to a truck,
and wheels it out of his shed; he then prepares his mould for the next plate,
removes his cinders, and repeats the operation. The quantity of refined metal
thus produced by a “double” furnace in Wales, is from 60 to 70 tons per week,
of 6 days of 24 hours each, the men working in turns of 12 hours at a time,
and 12 hours rest. The refiner selects his materials according to the quality of
iron wanted. The best quality is from the dark grey pig, or No. 3, and the infe-
rior sorts from bright, mottled, and white in their order. The very “worst’”
white iron cannot be used by itself in the refinery; being almost infusible from
its deficiency of carbon, it is disposed to clog and settle on the hearth. To
work up such iron in the refinery, it is mixed with pigs of a “better quality,”
or those containing more carbon, the union conferring fusibility. When
No. 3 pigs are used, it requires about 22% cwt. of them to produce one ton of
refined metal; the “ yield” however varies, from causes before adverted to,
according to the degree of carbonation of the pig metal employed, the quality
of the coke, the management of the blast, and various other circumstances.
This reduction of weight is however not an entire loss, as a quantity of
3.
§
III;













5 E
766 IRON.
“cinder” is produced which floats on the top of the metal, and detaches itself as
it cools; this cinder contains usually about 50 per cent. of its weight of iron,
which is recoverable on the blast furnace.
The Puddling Furnace.—The next process consists in depriving the iron of
its remaining carbon and oxygen (or as far as that may be practicable), by
which it is rendered malleable and is constituted wrought-iron. For this pur-
pose the brittle plate of white refined iron is broken up into small pieces, and
brought to the puddling furnace, sometimes called the balling furnace, from
the circumstance of the iron being therein made up into balls, about the size
and shape of quartern loaves of bread. The furnace differs but little from an
ordinary reverberatory furnace, as will be seen upon reference to the subjoined
engravings, in which Fig. 1 exhibits a vertical and longitudinal section, and
Fig. 2 an horizontal section or plan. As a strong flaming fuel is required in
this operation, coal is employed in preference to coke, the gaseous portion of
the former being rendered available as fuel. At a is the ash-pit; b a series of
N
Fig. i. - º | Æ
2i.
: º
§ W
sºuliº
tºlº
*=º
Fig. 2.
loose grate-bars, on which is deposited the coals introduced through an aperture
c kept closed, except during the charging or stoking, by heaping up the small
coal against it externally, where it is formed into a cast-iron receptacle for the
purpose, resembling a coal scuttle; at d is the fire-bridge, frequently made
hollow by an iron casting, as shown in the drawing, and encased with fire-
bricks; this hollow casting is connected externally with a vertical pipe to
convey off the air, which is caused to pass through the fire-bridge; and by the
heat it thus abstracts, the fire-bridge is prevented from becoming fused by the
intense action of the flame. At e is the basin of a bed of sea sand spread into
a concave shape; it is supported upon a stratum of fire-bricks, which lie on
solid masonry fibeneath. On this bed the refined metal is placed and exposed
to the heat of the flames, which are made to impinge downward upon the
metal in a constant stream, owing to the curved form of the roof, against










IRON. 767
which the current of air that passes through the grate-bars strikes; from the
metal the flames again ascend, passing over a dam g, through the throath, into
the chimney i, which is carried up from 30 to 40 feet high, and is provided with
a damper at the top, by which the puddler regulates the degree of draft, and
consequently the heat of his furnace; for during some parts of his operations,
he requires a more intense heat than at others. The draft through these fur-
naces is frequently so great as to cause the flames to ascend above the chimney
top, and to make the damper, situated there, red hot. At j is a sliding door,
suspended by a chain, and raised or lowered by a lever k ; at the bottom of the
door is a small aperture (as shown in Fig. 1) employed as a spy-hole, and for
the introduction occasionally of the puddler's tools without opening the door.
There is also usually another small aperture at l, lined with a cast-iron box or
case, and divided by a partition into two cavities, through which the “shingler”
puts his iron bars to be heated, as will be hereafter explained. The dam g
before mentioned is deeply grooved or furrowed (as seen in Fig. 2) to allow the
cinder or slag to run off into a pit m, whence it is discharged through an open-
ing o out of the furnace. The chimney is bound together at different points
with iron, and the external sides of the body of the furnace is encased in iron
plates, bolted through the brick-work. All these precautions are, how-
ever, insufficient to prevent the early distortion of the fabric, and which would
without them soon fall into ruins by the destructive effects of the fire. The
employment of a sand bottom to the furnace, it is proper to mention, is now
getting into disuse in many parts, where, in lieu of the sand, a thick cast-iron
plate forms the bottom, on which is strewed a coat of the oxide or cinder made
in the puddling process. The puddler, is assisted in all his operations by an
inferior workman, termed his “under-hand,” who is not recognised by the
master, but paid by the puddler. The metal being put into the furnace, the
door is shut down and carefully closed to prevent the admission of air, as any
admission of air otherwise than through the grate-bars, tends to derange or
moderate the proper current. In about half an:hour the metal begins to fuse,
at which time the severe labours of the puddler begin. His first business is so
to dispose the pieces of melting metal, that those which are the least exposed
to the action of the flame may be drawn more immediately under its influence,
and that the whole quantity may be brought to the same fluid state, as nearly
as possible at the same time. If it is not so managed, that which is first melted
begins to burn and waste before the other is ready, and the yield is therefore
inferior than when all goes on well together. When the whole is melted, the pud-
dler, sometimes with a tool turned at the end like a hoe, and sometimes with a
flat one, stirs it about diligently in all directions, exposing every part of it in
turn to the action of the flame. In doing this he is obliged to be constantly
changing his tools, which soon become red hot, and are plunged, as they are
withdrawn, into a vessel of water to cool them. The liquid mass heaves and
boils as it is being stirred, showing the escape of elastic fluid. By degrees the
metal loses its fluid property, and assumes the appearance of a loose granulated
mass, the external particles of which appear in vivid cqmbustion, whilst the
main portion of it is less brilliant; these appearances indicate that the metal
is “coming round to nature,” as the puddler terms it; and to accelerate this
process, he frequently throws some water from a scoop on to the metal, and
occasionally adds a portion of the black oxide of iron formed in the subsequent
processes of the forge, by which the weight of his product of metal is increased.
He continues to move the mass about vigorously till it becomes so thick and
tenacious as to stick together and form into lumps. At this time the puddler
with great dexterity, exposed to a severely scorching heat, and a light of the
most dazzling brilliancy (which no ordinary person can even look at but for an
instant), separates the metal into masses resembling in size and figure quartern
loaves of bread, but weighing from 50 to 80 lbs. each, called “puddled balls,”
and having arranged his batch of metal upon their vitrified bed, they are left
there exposed to the continuation of the heat, until they can be successively
extracted and delivered by the under-hand to the shingler. By this mode of
puddling, a loss of time is incurred, by the heating of the fresh metal for the
768 IRON. S
next batch, amounting to nearly half an hour, besides the waste of fuel during
that period. To obviate these losses, various contrivances have been resorted to
for heating the fresh charge of metal, whilst the previous batch of puddled
balls are being shingled or rolled. The simplest and most improved plan deserves
mentioning. It is merely to make the body of the furnace longer than usual,
and to have a second door between that where the puddler works and the
chimney. This affords sufficient room for the succeeding charge of metal, which
is at the same time so near the workman that when .#. completed the heat
and sent the balls to the shingler, the newly-prepared charge is just in the
right state for him to bring forward and recommence his operations upon. By
the puddling furnaces first described, but seven heats could be completed in the
turn of twelve hours; but with the improved furnace, nine heats are effected in
the same time by one puddler, the results being two-ninths more of iron,
without any additional quantity of coals.
Malleable iron produced direct from the ore with stone coal.-A short time ago,
a patent was taken out in America, by Mr. B. Howell, of Philadelphia, for an
improvement in a “bloomery furnace,” “ by means of which, and the use of
anthracite coal exclusively for fuel, iron ore is directly converted into malleable
iron.” As this invention would be of immense importance to the country,
if it could be brought successfully into operation, (and we can discover no
reason why it should not,) we deem it right not to omit giving a description of
it in this work.
The specification, after adverting to the drawings, states, “By these, and the
notes and references appended thereto, it will be seen that this furnace combines
within itself the advantages of a close furnace and an open fire; in this respect
differing essentially from any other now in use for similar objects. In the
upper or close portion, being all that above the hearth, with anthracite coal
excited by a proper blast, a degree of heat is obtained much greater than can
possibly be generated in the ordinary fire with charcoal; while the lower por-
tion opening into the hearth, and permitting the free action of blast upon the
burthen, performs all the offices of the open fire, or forge. The size of the
furnace and the proportions may be varied, if the principle of the close and
open fire be retained. The furnace being first heated up in the manner
of a common cupola, the process is thus conducted ; the coal having settled
sufficiently for that purpose, it is charged with the proper burthen of ore,
which will vary according to the quality and kind. The charges are then con-
tinued alternately of coal and ore. The ore soon arrives at the tuyeres in a
state of partial fusion, and is then, by the intense heat of that part of the fur-
nace, quickly separated from its earths, and then rapidly descending into and
below the direct action of the blast, a large part of which is driven out at the
open front, first passing over that portion of the ore which has reached the
hearth, it is thereby brought, in the language of the workmen, “to nature,”
or, in other words, into malleable iron. As it sinks into the region of the blast,
the small masses may be driven into one, and a loup shaped by giving a proper
direction to the pipes at the different tuyeres, and the loup can be removed
with a proper instrument; another instrument, or strong iron bars, being intro-
duced at B, to hold up the burthen while this is doing. The loup may be drawn
into a bloom under a forge hammer, or passed through rollers. In either
operation, it will, of course, be necessary to renew the heats, which may be
done in a common chaffery, or in a heating furnace. This process is continued
at the pleasure of the workmen, and as soon as a quantity sufficient for a loup
accumulates, it is withdrawn, as above described. In the early stage of the
operation, it will be necessary to charge the furnace, nearly, or quite to the
top; but as the heat increases, the height of the coal may be gradually
diminished; and at a very high temperature, from two to three feet of coal will
be found sufficient. The cinder produced in this way will bear working a
second time; an appropriate flue facilitates the operation, and as it is first
fused, and sinks, and is thus interposed between the iron at the bottom of the
hearth, and the coal, it contributes to prevent a mixture of the two. Holes
may or may not be left in the sides of the furnace for the introduction of bars
IRON. 769
to aid in detaching the iron from the bottom and sides; but this will often be
necessary, if the back of the furnace be thrown sufficiently forward, and a
proper direction be given to the blast; for which purpose, tuyeres are placed
in different positions on three sides of the furnace, and at different elevations.
One or two pipes may be used at pleasure. From the foregoing, it must be
obvious that by the rapidity of the process, the saving thereby of time and labour,
the substitution of a cheaper, more powerful, and abundant fuel for that now
in use, and which is so made applicable to this object by the peculiar construc-
tion of this furnace,—a great and important improvement has been effected
in the conversion of iron ore into malleable iron. The following drawings,
Figs. 1, 2, 3, represent an elevation, and vertical and horizontal sections, all
drawn to a scale of one inch to three feet, the same letters referring to corre-
sponding parts of each. A is the tunnel head, where the furnace is charged;
Fig. 1.
}
º
|
º ||||}}
º i
º ;
:
º
to be provided with a cover, which is placed on in the intervals of charging,
when the coal is low. B a projecting, open, hollow hearth, for the reception of
cinder and iron, with a cinder hole at C, to be opened when it is wished to
draw off the cinder. D D are tuyeres
for the introduction of the blast, placed
Fig. 2.
in different positions on three sides of
the furnace, and at different elevations, ==r-s
to vary the direction of the blast at #### |
different stages of the process. The .
back and front walls may both or either ===
* * * EE
be thrown or inclined somewhat more ==
inward than is represented in the draw- É
ing, and as indicated by the dotted É
line on the vertical section; and with -->
advantage when the ore is not very
pure, and makes much cinder. The *H
furnace is to have over it 2. brick É
canopy or chimney, to aid in carrying JD *#
off the gas given out by the coal. The | _B
furnace is lined with fire brick, and is -
cased with cast-iron plates, secured by #
strong bolts, keys, and screws, and
between the casing and the lining,







































770 IRON.
common brick, with a thin packing
of sand; the latter, to prevent injury
from expansion. In a letter to Dr.
Jones, (the editor of the Journal ºf
the Franklin Institute) Mr. Howell,
the patentee of the furnace just
described, states that he had com-
pletely succeeded in making bar iron,
and even nails with it, without suf-
fering the iron to cool; and that
practical forgemen, who performed
the manual labour, were astonished
beyond measure at the result; the
iron being as good as that made at
the neighbouring forges in the old way.
Refining with Mineral Coal.—A patent recently granted in America, to Mr. C.
Lewis, (of Pine Creek, Alleghany County, Pennsylvania,) for refining pig iron,
seems also to be well deserving of the attention of the English manufacturer.
The process is chiefly effected by mineral coal, uncoked, but in such a manner,
that the metal while in a state of fusion is not brought into contact with the
mineral coal. A reverberatory furnace is employed; the mineral coals are put on
the grate-bars, and when the furnace has acquired a melting heat, a door at the
side of the furnace is opened, through which a bushel of charcoal is introduced
into a basin ten inches deep, previously covered with a stratum of silicious sand;
over the charcoal is distributed, so as to cover it, a bushel of hammer or forge
cinder, and then about a ton of pig metal, so laid around the basin as to leave
a space between each pig; thereby a greater surface of the metal is exposed to
the action of the flame. The fire in the grate is now to be well supplied, and
maintained; and all access of air prevented, except through the grate. In
about half an hour, the metal will be nearly melted, which, when the workman
perceives to be the case, he drags, by means of an iron rabble passed through a
hole in the door, the whole of the metal from the sides, into the basin. He
then introduces from three quarters to one bushel of charcoal upon the surface
of the metal in fusion. The fire being kept up, and the metal frequently
stirred, it will, in half an hour after the whole is melted down, be sufficiently
decarbonized to let it run out of the furnace. The consumption of mineral
coal in this operation is from 15 to 18 bushels, and two of charcoal of wood, to
each ton of metal; and the ton of metal is obtained from only 22 cwts. of pigs.
Owing to the intense heat of the furnace, the volatile parts of the coal are
consumed, or pass along the roof of the furnace into the flue, while the surface
of the metal is protected by the charcoal and the scoriae, which in all cases keep
uppermost without incorporating with the metal. Refining after the above
way will be of great advantage to forges that make their blooms by means of
charcoal, as it will greatly facilitate the procedure, and lessen the quantity of
charcoal used. The iron made in the manner described is said to be quite malle-
able, close in texture, and fibrous. It is worthy of observation, that this furnace
requires no machinery attached to it, and the process appears calculated to effect
some important savings to the manufacturer.
Salts employed in making Iron.—A patent was taken out a few years ago, by
Mr. Luckcock, an iron master of Edgebaston, near Birmingham, for the appli-
cation of the muriate of soda, (common salt,) to the iron in the puddling fur-
nace just as the metal is breaking down into fusion; the action of which was
said to be productive of that toughness and malleability which had previously
been only effected by laborious and expensive mechanical agency. The pro-
portion of salt to the iron was about two per cent. by weight. How far expe-
rience has proved the advantage of this mode of seasoning the puddlers' balls,
we are not informed; but it might be presumed to have been successful, from
its having excited the rivalry of others, who have since taken out patents for
salting iron ; amongst these we may particularly notice Mr. Josias Lambert, of
Liverpool Street, London, who appears to have availed himself of some hints
†

IRON. 771
out of an old fashioned receipt book. This gentleman adds (in his first
patent, 1829,) potash to Mr. Luckcock's soda, in the proportion of one part of
the former to two of the latter; and of this mixture he administers 15 pounds
to the ton of ore in the blast furnace; in the refining furnace 123 lbs., and in
the puddling furnace, 11 lbs. to the ton. Mr. Lambert, in the succeeding year,
1830, took out another patent, entitled “an improvement in the process of
manufacturing iron,” &c. This improvement consisted in the addition to the
former mixture of two parts of lime ! thus making it two parts of “salt,” one
part potash, and two parts lime. But notwithstanding this powerful and novel
auxiliary, he does not diminish the quantity of the mixture, but nearly doubles
it. After this explanation of the nature of these presumed discoveries, it will
be unnecessary to enter more into detail, as respects the quantities of the
fluxes to be used in the several successive processes of the iron manufacture.
We should not indeed have noticed these two last patents at all, were it not
from the circumstances that this species of iron cookery has been, and is pro-
bably, still conducted upon an extensive scale. . Of the novelty of the
scheme, every chemist must be aware, that all the substances mentioned
have been unscrupulously used as convenient fluxes in the assay furnace
for a century or more; and as respects the eligibility of their employment in
the great laboratories of the present day, we have the scientific and practical
authority of Mr. David Mushet, for observing that they are considered
useless.
The Forge, Rolls, &c.—For the purpose of introducing some recent improve-
ments connected with the previously described departments of the manufacture,
we broke off our narration of the usual train of proceeding of an iron work at
page 768, where we left the puddlers' balls in the furnace ready for subsequent
operations. Hitherto, we may observe, imagination has had to picture to itself
the intense action and changes that have been going forward, unseen, and
unheard; but henceforward, to the completion of the wrought-iron bar, the
rod, and the sheet, all is activity and motion. The departments where those
articles are produced are contiguous and open to each other; they are termed
the forge and the mill, and are more or less extensive, according with the mag-
nitude of the iron work. The impression upon a spectator, to whom the scene
is novel, is one of extreme interest, and one that he never forgets; he finds
himself in the midst of machinery of a peculiar character, and of extraordi-
nary magnitude, remarkable for its massiveness and its weight, and in its
effects astonishing. In the mill, at regular intervals of about a minute, he sees
the distant gloom dispelled by the rising of a furnace door, which opens to his
view a chamber full of dazzling light before which stands an invulnerable
workman, who pulls from the midst of it a lump of iron, blazing like a meteor,
and dashes it upon the ground. Almost as quick as thought, and before the
furnace door can be closed again, the ignited mass of metal is eagerly snatched
up by another workman, with a pair of tongs, who instantly applies it to the
largest grooves of a pair of solid cylindrical “rolls,” which are revolving with
great velocity, and with such immense force, that the mass of iron is, as it were,
shot through the rolls, and is so far altered in its figure, by the compression,
as to be doubled in its length. Notwithstanding the rapidity with which the
iron moves by the revolution of the rolls, it is uniformly seized as it comes out
by another workman, who, with his assistant, tosses it back over the top roll,
where it is again taken by the first workman, and passed through the next pair
of grooves, smaller than the former; it is again seized by the workman on the
opposite side, and treated as before; and thus it travels backward and for-
ward, spontaneously illuminating its path by bright scintillations, through half
a dozen or more successive grooves; all the while lengthening itself, perfecting
its shape, and improving its quality, till it arrives at the end of its journey in
about a minute after starting from its fiery chamber. The spectator, who may
have taken his stand at a convenient distance, and has scarcely been able to
comprehend more than the possibility of what he has seen done, from the celerity
of its execution, is probably obliged to move farther off by the scorching heat
of the still bright red, long, finished bar which has reached him. This bar has,
772 IRON.
however, not passed its last channel before the effulgent furnace again opens its
mouth, and another bright mass of metal is ready to follow the first ; and thus,
bar after bar is made till the contents of that particular furnace are discharged.
During this splendid operation, the spectator has perhaps scarcely looked around
him; to see a fly wheel, of twenty feet in diameter, and of ten tons weight, cutting
through the air at the rate of ninety revolutions per minute; (more than 60 miles
per hour,) driving by means of a massive cog-wheel on its axis, numerous other
wheels at different velocities, to communicate the requisite power and motion
to various other mechanism contiguous and remote; to observe that through the
medium of other gear of due proportions, the ponderous rolls are made to turn on
their thick axes or “necks '' twice as many times per minute as the great fly; to
trace the cause of motion of the latter, through a stout pinion on its axis, driven
by a great toothed wheel, which is turned by a crank attached to the lower
extremity of the heavy vibratory connecting rod of a magnificent steam engine,
which, in its own separate apartment or house, is quaffing its potent vapour in
silence, and distributing its constantly renewed energies around to all that
require it; not excepting the ponderous machine which we shall next describe,
the effects of which are the reverse of those which are complained of in the
trunkmaker's hammer.
Shingling or Blooming.—The “underhand” having drawn a ball out of
the furnace, his superior, the “shingler,” takes it up by a pair of tongs and
heaves it on to the depressed part a of an anvil b, which with its block (sunk in
the ground, and resting upon solid masonry) weighs several tons, at the same
time another shingler, whose turn it is, (there being two shinglers to each
hammer,) draws out of the furnace a stout flat bar, one of the two before men-
tioned, the end of which has been brought to a welding heat, and holding the
cooled end wrapped round with a piece of nail bagging, he lays the heated
end upon the ball under the hammer c, the first blow of the latter forces the
bar into the ball flush with its surface, and they are thus instantly welded
together, and form as it were, one piece; the bar thus becoming a long handle,
by which the shingler can move and turn the ball about upon the anvil
between every blow of the hammer. This hammer with its helve d weighs
between four and five tons, and makes upon an average about 150 blows per
minute; it is actuated by the revolution of a cylinder e, in the circumference
of which are fixed, at equal distances, four or more wipers or coggs ff which
successively come into contact with the underneath side of the extremity of the
hammer helve, and thereby lift it up after each blow about 18 or 20 inches,
whence it falls simply by its own weight; which operates so effectively as to
reduce by a very few blows, the shapeless ball into a bloom. This bloom is a
rough square bar, usually about 20 inches long, and 4 or 5 inches thick.
By reference to the foregoing figure, it will be observed that the hammer head

IRON. 773
has not an uniform flat face, but is of a varied form, and has several projections
which answer to the rounded ends of common sledge and hand hammers,
termed panes; by placing the bloom under these projections, crossways, the
bloom is extended lengthways; and by placing the bloom so that a pane shall
strike it lengthways, its breadth is increased, and the grooves or dents which are
thus made are worked out by bringing the bloom under the flat parts of the
hammer. The effect of the hammering is not confined to giving it a new form,
but a large quantity of dross is thereby worked out, and the sparks and scales
fly off with great force, so that the workmen are obliged to be protected with
thick leather aprons, leggings, &c. It sometimes happens, through mismanage-
ment on the part of the puddler, that a ball has not sufficiently “come round to
nature,” and it shows its indisposition to submit to the gentle correction of the
hammer by hissing and bubbling. This species of bloom is called a shadrach,
and it is thrown back to the puddler, who has to pay a fine for having drawn
it out of the furnace before it was sufficiently purged of its impurities.
Shingling Rolls.-In this early state of the manufacture of malleable iron, the
office of the hammer just described is generally confined to giving the bloom only
about fifteen or twenty blows, by which it is brought into a shape that will permit
of its being, while still of a bright red heat, passed through the shingling rolls.
The precise form of the grooves in these rolls is not material, and they differ
in most works; the intention is to reduce the bloom as quickly as possible into
a broad, flat bar, for a purpose that will presently be explained. In the annexed
sketch, which we have made to illustrate the subject, two different kinds of grooves
74
z : %
–
||
r-sº-
-
are introduced, both of which are employed. In the above figure, u u represent
the upper roll; l l the lower; ss are the standards through which the necks of
the rolls pass, and are therein made to revolve in opposite directions by the
action of the pinions pp in gear with each other, to the shaft of one of which
the power is applied; and by a continuance of such shafting, connected by
clutch boxes, motion is sometimes imparted to a series of pairs of rolls, arranged
in one line. In the preceding figure, the dark spaces between the rolls,
respectively marked a b c de fg, show the form given to the bars as they pass
through those grooves. The bloom is supposed to be first put through a, and
then through the others successively, until it is brought out at g in the form of
a flat bar four or five inches broad, and half, or five-eighths of an inch thick.
By the severe squeezing which the bar undergoes in passing through these
rolls, an additional quantity of cinder or foreign matter is forced out of it; and
it is worthy of remark that the grooves a b c powerfully contribute to this effect.
The form of them is not designed to be an equilateral hexagon, but that of a
square with the top and bottom corners taken off. In the horizontal line
the angles are right angles, the bar will therefore in that direction be made
wider than in its vertical breadth, where the angles are obtuse. Besides, there
are usually between the rolls, where they are intended just to touch each other,
little vacancies, into which the iron is compressed in its passage, and a burr is
thus formed upon its angles; now, by turning the bar so as to present the
right angles and burrs to the flat top and the flat bottom of the same, or the
J. F.


774 IRON.
next pair of grooves, they are thereby crushed down, and the dross is thus more
efficiently worked out of the metal, and by the time it arrives at g, in the form
of a flat bar, it is considerably improved in its toughness and malleability.
Nevertheless, the iron is of an unmerchantable quality; it is still impure; is
too easily broken; has a rough scaly surface, and its edges are imperfect.
Shearing the Bars.--This rough bar is therefore, immediately it has passed
through the rolls, and while it is still red hot, put between the jaws of a pair
of shears, worked by the engine, and cut into lengths of about a foot each. A
pair of shears for this purpose is represented in the engraving of the great
hammer at page 772, by reference to which the reader will readily comprehend
our explanation of them. That portion of the shears marked g g g, is one mas-
sive casting, and is fixed to the ground in the most solid and substantial
manner. The cutting edge of the lower chap at h is formed out of a stout
steel bar; it lies in a rebate, and is therein fastened by screw bolts. The chap
of the upper shear i i is similarly provided; this shear is the movable one, and has
its joint or centre of motion in the upright at g. By the revolution of the drum
e, it carries round with it an eccentric or solid crank k, to which is jointed a
stout iron bar l, which bar being jointed at its other end to the upper shear,
communicates its own vibratory motion to the shear, and makes it cut at
each alternation of the stroke or revolution of the drum. To prevent the steel
edges of the shears from being softened by the contact of the hot bars, a small
stream of water is made to flow over them constantly, brought on by a small
pipe, or other suitable channel, and regulated by a cock. The bars as they are
cut, fall into an iron barrow or truck, in which they are wheeled away to the
iler.
p Piling.—The piler piles the pieces of the rough bar together in the manner
shown in the annexed cut, putting as many upon
one another as will form a bloom or a finished bar of Er
the size and weight required. The piles are then ==
taken or deposited in a convenient situation for
being put into—
The balling or reheating Furnace—This furnace is in no essential respect dif-
ferent from the puddling furnace already described; but the men who work
them are usually called “ballers.”
Balling.—With an iron instrument of the shape of a baker's peel, the baller
places each pile on the bed of sand prepared to receive them, taking care not
to disturb them, so as to cause any of the pieces to project beyond the rest, as
these projecting pieces would, in consequence, be sooner heated, and sustain a
severer action of the fire than the others, causing those exposed parts to burn
or waste, and the whole mass to be deteriorated in tenacity. The number of
piles put into the furnace is regulated by their size, in order that when they are
sufficiently heated they may be quickly discharged; and as large heavy bars
take longer to roll than small light ones, a less number of large piles are put
into a furnace in making large bars, than of small piles in making small bars.
Notwithstanding the baller arranges his batch so that the piles may be com-
pletely heated in succession, he exercises his judgment upon them with his
eagle-like eyes, as to which bloom is in the most forward state. The ballers’
proceedings are likewise regulated by the state of the other balling furnaces of
the work, whose products are successively worked off. If a baller keeps his iron
too long in the furnace, it is thereby rapidly wasted and deteriorated; on the other
hand, he must be ready to a minute, that the rolls may be constantly at work,
and that the power of the engine may not be wasted. The blooms that are now
taken out of these reheating furnaces, are presumed to be of a quality adapted
to the manufacture of common bar-iron, of which there is a very extensive
variety of forms; but the great bulk consists of three kinds, namely, flat, square,
and round, the latter being usually termed bolts. Of the three last-mentioned
classes, there are very numerous sizes, as will be seen on reference to the tables
subjoined to this article.
Kariety of Rolling Apparatus.-For the manufacture of so extensive a variety,
a great number of rolls is required in an iron work. The stock of these

§
t
IRON. 775
ponderous tools, in some works, consists of upwards of a hundred pairs; and there
are commonly from ten to twenty pair of standards (fixed in the most firm and
solid manner that art is capable of) ready for their reception. A sufficient
example of this kind of mechanism for making flat bars has already been
given at defg, in the cut at page 773: in the illustration which follows, the rollers
for making round and square bars are shown. These rolls are called finishing
rolls, for the bar, previously to being brought to them, is passed through several
grooves of a pair of roughing rolls, which are of greater diameter than the
Fig. 3.
H
C]
Q
º
finishing rolls, and furnished with larger grooves. In these last-mentioned, the
bars are reduced to nearly the intended size, and they are then run through
two or three grooves of the finishing rolls; each time that a bar is passed
through, whether round or square, it is turned a quarter round to take off the
burr or fin, formed at the junction of the rollers, and through the last hole it is
usually passed twice, by which its figure is perfected. The effect of the piling
and reworking the iron, as just described, has been to weld the several layers of
the pile together, which thus become one solid mass, possessing a fibrous tex-
ture and an increased toughness; and during the operation, many of the
impurities that the iron had retained are expelled. In rolling flat bars, the
treatment is different from that of square and round; the pile is never presented
to the rolls with the edges of its layers upwards, but always with their flat
sides horizontal; for were the bar rolled upon the edges of the layers, the
welding would probably be very imperfect, and the bar comparatively weak.
Each bar after it is completed in the rolls, is taken by two boys with tongs,
who first put the marks on with steel punches; they then present its extremities,
which are usually ragged and uneven, to be cut off by a pair of shears that
are constantly opening and shutting by the action of the engine; the boys then
take the bar, and lay it along a solid cast-iron bench, perfectly flat, and having
a straight edge on one side; and as the bar is still hot, they easily make it per-
fectly straight by a few blows with wooden mallets.
Process of Rolling—Defects and Improvements.--To give the reader a clear
insight into the mode of working a bar through the rolls, it appears to be
necessary partly to repeat what has been before but imperfectly noticed. A bar
of iron, as it passes through each successive groove of a pair of rolls, is received
on the opposite side by two men, one of whom draws it out by the end with a
pair of tongs, and the other supports it by a lever to prevent its making too
sudden a bend; and when the bar is through, these men pitch it back again
over the top roll for it to pass through the next groove; and this operation is
repeated until the bar is reduced to the required size, Now it must be evident
upon reflection, that this returning of the bar over the rolls occupies about as
much time as the actual rolling; consequently that the iron becomes cooled in
proportion, harder, and requires more power to roll it; that the workmen have
a very severe labour to perform, and are all the while exposed to a scorching heat.
These defects in the ordinary process of rolling forcibly struck the writer

776 IRON.
several years ago, when he proposed two methods of continuous rolling,
by which it was estimated that the manual labour would be greatly reduced,
the personal inconvenience diminished, the cost of the machinery lessened, and
one-half of the power of the engine sayed. The first of these plans was to
place a series of pairs of small rollers (that is, short in their axes) one before
the other, so that the bar might pass in one continued straight line, from groove
to groove, until finished of its intended dimensions. This plan is explained
by the annexed diagram; a a, b b, and c c, represent the transverse sections of
three pair of rollers, with grooves of different depths; the bar is supposed to
enter at d, and by passing through the rollers a a to be reduced to the size e,
where the bar slides upon a form h, guided thereon in a straight line by a fur-
row of the shape of the bar, direct into the grooves of the rollers b b, the bar of
the size of e is here reduced to that of f, lying on another form h, which con-
ducts it through the rollers e e, and is thereby further reduced to the size of g,
or any other that may be required by a suitable extension of the apparatus.
By this method it was considered that a bar would be rolled in about one-third
the usual time; that the manual labour would be reduced to a trifling amount;
and that not one-half the usual power required of the engine would be
absorbed. The latter advantage results from the celerity of the operation; for
as the iron is much hotter, it is much softer, and requires a less amount of force,
even during the diminished time taken up by the process; but the most im-
portant advantage is, that a better bar is thereby made; when the maxim to
“strike the iron while it is hot,” has thus been duly attended to, the bar,
instead of being cracked at its edges or otherwise unsound from being rolled
when too cold, will be uniformly solid and of a more perfect form.
The second plan devised was to put Fig. 2
a series of small rollers one above *g. 4.
another, with the usual spur gear on
their axes, which would give every suc-
ceeding roller an opposite rotation, so
that the bar might enter between the
first and second roller, go back through
the second and third roller, then
through the third and fourth, the
fourth and fifth, and so on to comple-
tion. In the annexed, Fig. 2 affords a
side elevation, and Fig. 3, on the follow-
ing page, a vertical section of six small
rolls, a b c def, which, by their arrange-
ment, are in effect five pairs. In Fig. 3
the letters g h i kl, show the situation of
five shelves, (the proportionate length
of which cannot be shown,) on which the
iron slides; and the arrows in the same
figure indicate the course taken by the
bar through all the rolls. The shelf g is
supposed to be upon a level or some-
what lower than the mouth of the fur-
nace, the bloom from which is to be
slided down upon g, and pushed between
the rollers a and b, and as it passes
out of these, it gradually bends down,


IRON. 777
the end falling in the position of the
arrow at h, ready to enter between the
rollers b and c; then upon i between c
and d, upon k between d and e, upon l
between e and f, and so on to any num-
ber of rolls underneath, or be conducted
forward to another series of rollers
placed before it. Both the plans now
described may be employed separately
or jointly ; but for various reasons the
vertical series would be preferable for
roughing the work, while the hori-
zontal arrangement would probably be
best suited for finishing the work. It
is to be understood that the foregoing
diagrams are only designed as explana-
tory of the principle of construction, all
the subordinate details being omitted as
unnecessary in this place. Previous to
the year 1828, the writer had never
seen nor heard of iron being rolled on =
either of the plans described; he had
seen several iron works, one newly
built, in none of which, however, was
the principle adopted; he could find no
published account of any thing of the *R*= -—— . .
kind; his mechanical friends said the - f
plans were new and valuable, and a patent was determined upon if the opinions
of two or three respectable iron masters, whom he consulted, should be
favourable; when, singular to relate, two of these persons, who had very exten-
sive concerns, condemned the plans as useless and impracticable, while the
third said they were not only practicable, but highly advantageous; and he
proved the truth of his assertions by showing the writer his works, wherein
iron was at that time being rolled on the very principle of both plans, where
he was informed it had been practised for several years; and that similar rolls
were used in several of the works of Staffordshire I This fact has been men-
tioned with the view of inculcating circumspection in inventors before they
incur the expense of patents, and a disregard of dogmatical opinions when
unsupported by reason. It is worthy of remark in this place, that in none of
the recent treatises on the iron manufacture has any notice been taken of this
important improvement in rolling iron. The plan at the iron works where the
writer saw the principle in operation, is a modification of that which has been
described; it consists of only three rolls one above another, but of the same
kind as those delineated at page 775, so that a bar which has passed through
a groove between the top and middle roll is sent back through another
groove between the middle and lowest roll; and there being many grooves in
each of the three rolls, they are thus passed alternately through the upper and
lower range of grooves until completed; but in making vat hoops, the bar,
after being passed through several grooves, to roll it to a thin, yet rough
flat bar, proceeded onward horizontally (in the same manner as shown in the
diagram, page 776), and entered between a pair of plain polished rolls, where
it was reduced to the required thinness, and a smooth face was given to it.
Horton's mode of rolling large Bars.-For bars of still greater dimensions
Mr. Horton adopted the following process, for which he took out a patent a few
years back. Instead of rolling the single blooms, and then welding the bars toge-
ther, to get bars of the sizes required, he takes the blooms (“billets,” he calls
them,) from the puddling furnace, welds several of them together under the
great hammer, then submits the united mass to the operation of the rolls. Great
bars, thus prepared are said to possess a more laminated and fibrous texture lon-
gitudinally, than those which are united by welding together ready formed bars.

778 IRON.
The various Forms of rolled Iron,-Having seen that round iron is produced
by the junction of two semicircular grooves in the opposite rollers, the reader
will readily perceive, without the aid of a figure, that “half-round iron,” (that
is, semicircular in its transverse section,) will be produced by having only one
roller with a semicircular groove, and the opposite roller with no groove at all;
and that, by making the groove of less depth, that is, of an elliptical curve, a
semi-elliptical, or “half-oval” iron bar will be formed; also that by the junction
of two semi-elliptical grooves, “oval iron" will be the result. The two last-
mentioned sorts are extensively used by coach Smiths; also for the tops of
fenders, wire-guards, and such like. It will likewise be evident to the reader,
that as square iron is made by two angular grooves, one of such grooves opposed
to a plain roller will produce triangular, or “three-square iron;” that as flat
bars are made by grooves of this form -, it will be only necessary to make the
opposite groove deep and narrow, thus I, and let the latter groove come next to
one end of the former, to produce L or “angle-iron.” This angle-iron, though
of recent introduction, is, on account of its very great utility in making framing,
cases, boilers, and a thousand other things, a great favourite with all kinds of
smiths, as it enables them to execute superior work with much less labour.
Seeing how the angle-iron is made, it will be readily understood that, by placing
this I groove so as to come in the middle of this - groove in the opposite roll,
that “Tiron” will thereby be rolled; and this brings us to a clear understanding
how “railway-iron” is made, as the form is usually but a slight modification of
the T, by a little rounding of some of the parts; and by obvious combinations
of the foregoing, it will be seen how “iron mouldings,” of an infinite variety,
may be produced by a pair of rolls, and with far more facility and dispatch than
a joiner can make them of wood with his moulding planes.
Slit Rods,--The manufacture of this article is interesting from the wonderful
rapidity of its execution; and that it is of great importance in its results, it
need only be stated that in the neighbourhood of Birmingham alone, it furnishes
the highly-convenient raw material to upwards of sixty thousand people, men,
women, and children, who are employed in nail-making, besides being applied
to an infinite variety of other purposes. The slitting is performed by what we
would define to be a series of circular shears, formed by the continued contact
of a pair of deeply-grooved steeled rollers, which cut by the intersection of
their angular edges, as will be clearly understood by reference to the subjoined
engraving, which exhibits a pair of slitting
rolls, adapted to slit a flat bar or slab, of
about seven inches wide, into thirteen
equal parts. An end view of this slab is
intended to be represented at a, and by
presenting it between the two rolls at b b
it is obvious that the edges, as they inter-
sect each other in their revolution, will
divide the slab in the manner shown at a,
and force them into the cavities between
them, in which manner they will pass out
of the rolls in a finished state, requiring
only to be tied up into bundles afterwards,
of the usual weight of 56 lbs. To faci-
litate the operation of slitting, the bar
passes from the rolls where it has been
formed of the required dimensions, in its red-hot state, directly between the
slitters. In this manner upwards of thirty rods, of a small size, are made at
once by a single revolution of a pair of rolls. As the sizes and forms of the
rods required are extremely various, it is necessary in a slitting mill to have, at
the least, two pair of rolls for each size, that a freshly-turned pair may be in
readiness to supply the place of those which become worn or damaged. Slit
rods are always more or less ragged at their edges, but this is of trifling import
compared to the advantage of their great cheapness, especially in the making
of nails, where they have to be drawn out under the hammer. To prevent any

IRON. 779
considerable burr, or ruggedness of edge in the rods, the slitting rolls are turned
with great care and truth, so as accurately to fit each other
Rolling of Plate or Sheet Iron is performed between perfectly plain rolls, as
before mentioned, for hoops; but the rolls are necessarily of greater dimensions,
frequently as wide as five feet; and of course a very great power is required
to compress at once so extensive a line of surface. For ordinary sheet iron,
such as is called “double and single plate,” only one pair of rolls is employed
at a time, the rolls being set nearer together by regulating screws, each suc-
ceeding time that a sheet is passed through. In rolling boiler plates, which are
often more than half an inch in thickness, and weigh more than 2 cwt. each,
the manual labour is very severe. The iron for these plates is prepared by
making a pile of rough bars, which is heated in an air furnace, and then
subjected to the action of the great forge hammer, already described, which
reduces the pile to a thick slab, the forgers moving it under the hammer, so as
to give it somewhat of the figure, as to length and breadth, required for the
finished boiler plate. It is then heated again in the furnace, and rolled to the
required thickness by repeatedly passing the plate between the rolls, the rollers
adjusting the rolls nearer together each succeeding time, and taking due care to
present the plate in such positions as will extend it to the required shape and
dimensions, sometimes making it enter the rolls corner ways, sometimes length-
ways, and sometimes breadth ways; the skill and efforts of the workman being
directed to bringing the plate to the required form and dimensions at one heat,
and so as to require but very little superfluous edging to be subsequently taken
off by the shears.
Rolling Rods.-Round rods, and those of a square or flat shape, that are
required more perfect in their figure, and with a smoother surface than those
which are split by the process described, are made by rolling with small rolls
that are case-hardened, and have their grooves very nicely formed. They are
usually from six to seven inches in diameter, and make from 230 to 260 revo-
lutions per minute, and the rods, whilst between the rolls, are drawn through
them at the same velocity. They are rolled of great lengths, sometimes upwards
of forty feet, and are afterwards cut to the required lengths, and tied into
bundles of 56 lbs. each. Round rods are thus rolled so small (about three-
sixteenths of an inch), as to form a very useful and cheap substitute for wire.
It is extensively used by wire-workers, and in making “invisible fences;” also
by tinmen, coppersmiths, and other trades; but especially in those cases where
it is covered over, and employed to stiffen flexible substances.
Red-Short, is a term given to bar iron that has the defect of cracking or
breaking, when punched or bent, while at a red heat. It is generally very
strong when cold, and therefore useful in that state; and when it is worked,
care should be taken by the smith not to subject it to severe strains at that
peculiar heat in which it is disposed to give way.
Cold-Short, is that kind of iron that readily breaks when cold, but is easily
wrought under the hammer when heated.
Testing the Quality of Iron is usually performed by cutting a nick on one side
of it with a cold chisel, then bending it down, or giving it a blow with a sledge
hammer. If the iron be bad, or cold-short, it will break, and exhibit a re-
splendent, crystallized fracture; if, on the contrary, the uncut part bends back,
and exhibits the appearance of a bundle of silky-looking fibres, such iron will
probably stand the heated test of bending it double whilst at a cherry-red heat,
first in the direction of the pile, and afterwards at right angles to it. If the
iron does not crack by these tests, it is neither cold-short nor red-short, but of
a tough good quality. We have now given a pretty general outline of the
process of making common malleable iron, but there remains to be explained in
what respect the processes differ in the preparation of the superior kinds.
Best Malleable Iron.—The correct meaning of the term “best" is very
different to the signification of it in the iron trade, in which it now implies the
next better quality than common; and it is usually said to be made by a
repetition of the process at the balling furnace, the forge, and the rough rolls;
that is to say, the rough bar of the common iron already described, is cut, piled,
780 IRON.
and made into a bloom once more, which confers upon the metal a more fibrous
texture, and considerably increases its toughness and elasticity. We believe,
however, that much of the iron that is sold under this denomination undergoes
a different process, which does not improve the quality to the same extent. We
are informed that best iron is more commonly prepared from pig metal of a
better quality, namely, the dark grey, whose fracture is brilliant, and of a
silvery white colour. These are carefully refined and puddled, without any
admixture of inferior materials; the bloom is well hammered, and when rolled
out into rough bar, it is made thinner than for common iron; this is afterwards
cut into short lengths, piled, reheated, and rolled out to the required size, as in
common iron.
Scrap Iron.—There is another kind of best iron, distinguished by the name
of “scrap-iron,” being made up of all the scraps, short lengths, ends cut off
the finished bars, as before explained, and all the little bits of wrought iron
that can be collected together. Of these there is always a considerable quantity
accumulating in an iron work; the larger pieces are made up into piles, and
the smaller into balls. The piles may be heated to a welding heat, and rolled
at once into finished bars, but the balls, consisting of smaller pieces, are shingled
under the great hammer, to consolidate them and bring them into the form of
a bloom. This bloom is reheated, and when rolled, produces excellent tough
iron, superior to the piled scraps that have not been shingled. Scrap-iron, thus
reworked, often produces so excellent a quality, as to fall under the denomination
of the next described quality of iron, namely,
Best-best Iron, No. 3, Chain-cable Iron.—These names, and various others
intended to denote the superlative degree, are given by manufacturers to that
kind of iron which is deemed to be, in reality, of the best quality, prepared
with mineral coal. This metal is chiefly manufactured for the purpose of
enabling it to resist most effectually a longitudinal strain or tension ; and the
property is best acquired by the careful selection of the best materials, and
repeatedly cutting, piling, shingling, and rolling, as before explained. In the
preparation of this superlative quality of iron, the utmost attention to the process
is necessary; and any bloom or bar that may be incidentally injured in its
tenacity should be rejected by the manufacturer, whose reputation might be
injured by such iron receiving the mark that properly belongs only to the
primest quality. It is this kind of iron which is chiefly employed in the making
of chain-cables, in tie-rods and bolts, that are subjected to a powerful strain.
Charcoal Iron.—This term is originally applied to such iron only as had been
prepared solely with wood charcoal, from the ore to the malleable and finished
state; but now the name of charcoal iron is given to malleable iron, the ore of
which may have been smelted with coke, in the ordinary blast furnace; and it
acquires its distinguishing name from the circumstance of its being refined with
wood charcoal. The process of refining, and also that of puddling, are per-
formed as one in a puddling furnace, wherein it “comes round to nature,”
combined with less impurities than by the common mode described. The bloom,
when taken out of the furnace, is put under the heavy hammer, and brought
to the form of a flat cake, when intended for sheet iron, in which state it is
denominated stamped iron. The stamped iron is next broken into pieces, piled,
heated, and again put under the hammer, which reduces it to a slab of about
one hundred-weight. These slabs are used for a variety of purposes; but their
chief application is by the manufacturers of tinned plates, who reduce the
“charcoal slabs” to the required thinness preparatory to the tinning operation.
(See TINNING.) When the charcoal iron is required for bars, it is treated in all
respects in the same manner as in making of the very best chain-cable iron.
Owing to the large quantity and expensive nature of the fuel employed,
charcoal iron is much dearer than coke iron; yet, from its great toughness and
uniformity of texture, it is always preferred by engineers in the fabrication of
steam-engine boilers, and, generally speaking, for all the important parts of
machinery that are liable to severe tension.
. Re-manufactured Iron.—Worn-out and broken articles of iron, termed old
iron, are collected throughout the country, and purchased by a class of tradesmen
1RON. 781
called dealers in marine stores, who sort them into three kinds for sale. The
first is called “coach-tire,” and consists of the old wheel tire of carriages, and
other large pieces; the second is called “nut, or scrap iron,” and consists of
nuts, nails, screws, holdfasts, hinges, and an infinite variety of little solid
pieces; the third is called “bushel iron,” and consists chiefly of very thin
articles of iron, such as those which have been of rolled sheets or hoops. The
last-mentioned is of the least value, on account of the great waste by oxidation,
and the trouble attending it. The iron so collected and separated by the dealers
is so considerable in and near London, that although a large portion of it is
sent by the Grand Junction Canal to the works in Staffordshire, and another
large portion of it is shipped on board the coal ships, in lieu of ballast, for the
Newcastle works, still there is a sufficient supply for three iron works near
the metropolis; namely, one at Wandsworth, another at Chelsea, and a third
at Rotherhithe. The last-mentioned, called the King and Queen iron works, is a
very old establishment, and the most considerable of the metropolitan works,
the quantity of hoops and bars made there being from fifty to a hundred tons
weekly: the quality, also, of the iron manufactured at this work (well known in
the trade as King and Queen iron) is justly celebrated, which may be accounted for
by these circumstances—nothing but old iron being used, the machinery being
of the most improved kind, and a vigilant attention to the essential parts of the
process. By the liberality of the proprietor, Mr. Howard, we have had an
opportunity of inspecting this work, of which we shall give such a brief notice
as will enable us thereby to complete our account of the manufacture of English
malleable iron.
A number of poor women are employed in piling up the scrap-iron into balls,
as they are called; but the form is that of a short cylinder, resembling in size and
figure the crown of a man's hat, somewhat narrower at the top than at the
bottom. A flat circular piece of sheet iron forms the foundation, and on that
is raised the fabric, the larger pieces on the outside, the smaller in the inside, to
fill up the interstices, and the whole as solid and compact as can readily be
done. Care is especially taken not to put any little bits of brass or copper that
may be accidentally mixed with the iron into the piles, which would prevent
the consolidation or welding of the mass; and, to encourage the vigilance of
the pilers, they are allowed the copper and brass they may thus find as perqui-
sites. The balls are put into a reverberatory furnace, similar to the puddling
furnace we have described: when brought to the proper welding heat, they are
subjected to compression by a “squeezer;” this is necessarily a very strong
machine; it is composed of a fixed lower jaw, of great massiveness and breadth
(about a foot of superficies) on which the ball is laid, and is operated upon by
the motion and force of the upper jaw, which, being actuated by the engine, is
continually opening and shutting during the process, and thus it chews, as it
were, by half a dozen or a dozen bites, the great ball of iron into a suitable
shape to be passed between the shingling rolls, whereby it is, in a few seconds,
reduced to a short, very thick bar or bloom. This bloom is re-heated in an air
furnace, and then it is reduced between the rollers to a bar, a plate, or a hoop,
equal in quality to the “best iron” from pigs; but it is, nevertheless, the com-
monest iron made in this re-manufacturing process.
We have now to explain the mode of preparing the larger pieces of old iron
before-mentioned for re-manufacture. A number of men and boys are employed
in clipping, with large fixed hand shears, the old hoops into convenient lengths,
and other old articles into suitable sizes, to be afterwards made up into bundles,
called faggots. The wheel tire, which requires great force to cut through, is
effected with a pair of shears worked by the steam-engine: the materials, as they
are cut, fall into barrows, in which they are conveyed to the faggotting depart-
ment, where several men are employed in preparing the faggots at a stout bench,
on which are fixed convenient little machines, for facilitating the operation.
One of these is represented at page 782. a a is a stout bridge-piece, in the centre
of which works the screw b, by turning the handles c c, d d are two forked
bearers, in which are laid two soft iron bands e e, bended to fit the square to the
bottom of the bearers. On these bands is first laid a piece of wheel-tire f; on
sºf
3 G
782 IRON.
this tire, pieces of hoop and other thin stuff are then evenly laid, which last are
covered with another piece of tire g. Their crooked or curved forms prevent
their laying so close together as is desirable; the turning of the screw, however,
forces them together very compactly, as shown in the sketch. Thus held down
by the screw, the bands e e are brought together and twisted, which holds them
fast, and the faggot is completed. The screw is turned back, the faggot taken
out, and others are made in like manner. The sizes of the faggots vary much,
being proportioned to the size of the bar, or other article to be made of it. If
not more than twenty or thirty pounds each, as required for making puncheon,
butt, or vat hoops, or small bars, they are, after being duly heated in the
furnace, at once rolled out into their intended dimensions. If the faggots are
large, they are heated and shingled into blooms, which are again heated when
required to be rolled out. It is the practice at these works, as well as others,
to prepare large quantities of blooms, to be kept as stock; but there is a great
economy in finishing the work by the first heat of the faggot, and this is
facilitated by the quickness at which the rolls travel in making the lighter
articles above-mentioned; and when, as at these works, the rolling is effected
by three rollers, one above another, by which the iron is rolled both backwards
and forwards (as before explained), a very long bar or hoop is completed in
little more than half a minute, and, consequently, while the iron retains a good
heat.
The first quality, or best king and queen iron, is thus prepared:—a ball or
faggot, being duly heated, is first compressed a little by the squeezer, then rolled
to a flat bar in the shingling rolls; the bar is next cut into pieces, piled,
re-heated, and made into a best bloom under the shingling hammer. This best
bloom is next re-heated, passed through the roughing rolls, and then through
the finishing rolls, whereby it is brought to the form required. It is an important
consideration, that much of the old iron used in the re-manufacturing process
was originally the “best” iron of the first manufacturer; and that as the
greater part of the old iron has been improved at the blacksmith's forge, it may
safely be said, that where the processes of refinement of the first manufacturer
leave off, those of the re-manufacturer begin: and as it is universally admitted
that the more iron is worked, the better it becomes, (which is indeed proved by
the extreme tenacity of fine iron wire,) it seems to follow, that the re-manufac-
tured iron we have been describing must be greatly superior to that which is
newly made from pigs, however carefully the process may have been conducted,
or however often it may have been repeated.
Russian and Swedish Irons, which were formerly usually employed in our iron
manufactures, are still applied extensively at Sheffield and some other places, in
the fabrication of the superior kinds of steel and fine cutting instruments; but
their application to other purposes is extremely limited, on account of their much

IRON. 783
greater cost than our own best charcoal iron, which is scarcely inferior for most
purposes to which bar iron is applied. The Russian and Swedish irons are
entirely converted and refined with charcoal by processes so similar to our own
as not to need description. These valuable foreign irons are more particularly
noticed under the sub-head Steel in this article.
Malleable Cast-iron. A very extensive manufacture of iron articles is now
carried on at Birmingham, Sheffield, and other places, which although they are
cast from fluid metal, are nevertheless malleable. This property is derived
from two causes; first, the pigs are prepared from the rich and pure iron ores
of Cumberland; and the metal thus obtained is combined with but a small
quantity of carbon, so as nearly to resemble steel in colour, hardness, and the
brilliancy of its fracture; and it has in consequence been designated by some
manufacturers, run steel. An infinite variety of articles, including nails,
saddlers' ironmongery, (and particularly such goods as afterwards receive
another metallic coat, as those which are plated upon steel,) are cast from
this metal. The castings thus produced are exceedingly brittle ; but this
property is entirely destroyed by a process termed annealing, in which the
metal is deprived of the carbon to which its previous fusibility was owing,
and is in consequence brought to that state of wrought iron requiring only the
operations of the shingling forge and rollers to give it a laminated and fibrous
texture. Nails made by this process may be drawn out longer, and bent
backwards and forwards, without breaking. The metal is however not so
strong, or tough as hammered and rolled iron; the discovery of the process is
nevertheless of great value, as many excellent articles are produced in conse-
quence, which would not without it be made at double the cost. The discoverer
of this mode of converting cast-iron goods into malleable, was Mr. Samuel
Lucas, of Sheffield, who took out a patent for it in 1804; the specification of
which we shall annex, as there are some manufacturers who, while they avail
themselves of Lucas's process, assume it to be their own discovery, in conse-
quence of making some unimportant variations. “I declare that my said
invention of separating the impurities from crude or cast-iron without fusing
or melting it, and of rendering the same malleable and proper for the several
purposes for which forged or rolled iron was used, and also, by the same
method, of improving articles manufactured of cast-iron, and thereby rendering
cast or crude iron applicable to a variety of new and useful purposes, is thus
to be performed:—the pig, or cast-iron, being first made or cast into such form
as may be most convenient for the purpose intended, it is to be put into a steel-
converting, or other proper furnace, together with a suitable quantity of iron
stone, iron ore, some of the metallic oxides, lime, or any combination of these,
(previously reduced to powder, or into small pieces,) or with any other substance
capable of combining with, or absorbing the carbon of crude iron. A degree
of heat is then to be applied, so intense as to effect an union of the carbon of the
cast-iron with the substance made use of, and continued so long a time as shall be
found necessary to make the cast-iron either partially or perfectly malleable, accor-
ding to the purposes for which it may be wanted. If it be intended to make the
iron perfectly malleable, from one half to two-thirds of its weight of iron stone,
iron ore, or other substance, will be found necessary; if only partially so, a
much less quantity will be sufficient. Five or six days and nights will in
general be found sufficient, during which to continue the heat, which towards the
close of the process cannot be too great. Care should be taken that the pieces
of cast-iron be not of too great thickness, as it would have the effect of length-
ening the process. But the proportion of the several substances made use of,
and the degree and duration of the heat to be applied, must greatly depend, not
only on the nature of those substances, but also on the nature and quality of
the pig or cast iron employed, a knowledge of which can be obtained only by
experience. The cast-iron to be rendered malleable, and the substances to be made
wse of for that purpose, may be placed in the furnace in alternate layers ; and in
order to prevent the iron stone, or iron ore from adhering to the iron, a thin layer
of sand may be placed between them. For the improvement of articles manufac-
tured of cast-iron, the same directions may be observed; earcept that when the
784 HRON.
articles are small, a less proportion of the substances for producing malleability
will be required, and also a less degree and continuation of the heat.”
Steel. We place this well known invaluable substance under the head of iron,
in preference to its own initial letter, considering that we may, with far more
propriety, class it under that denomination than cast-iron; for the latter, which
every body maintains to be iron, contains more foreign matter than steel, and
of the very same kind; cast-iron containing about 7 per cent. of carbon or
other matter, and steel considerably less than one per cent. ; even so little in
some specimens, as a four-hundredth part. Steel is besides so much like malle-
able iron, in density and hardness, that few persons, comparatively speaking,
know how to distinguish one from the other. The difference between common
steel and common cast-iron we understand to be this; that steel is a very com-
pact and nearly pure iron, rendered more dense and hard by an intimate com-
bination with a minute portion of carbon, with which in some specimens is
found manganese and silex; and that cast-iron is a less dense and very impure
iron, combined in an almost granulated state with a large proportion of carbon
and other matters. We are supported in this view of the subject by the fact
that in the manufacture of steel with bar iron and charcoal, by the process
called cementation, the iron is increased in its specific gravity; but if the pro-
cess of cementation be continued beyond the proper limits, the iron will absorb
more and more carbon, until it becomes disintegrated, and runs down into cast-
iron, the loose texture of which is indicated by its greatly reduced specific
gravity.
The specific gravity of steel is . . . . . . 7.827
92 malleable iron is . 7.788
33 cast-iron is . . . 7.207
Now white cast-iron contains much less carbon than black cast-iron, and in
consequence approximates more to the nature of steel. But white pig metal,
obtained from the generality of British ores, and smelted with coke, contains so
much impurity, that our manufacturers, rather than make steel direct, by
abstracting the principal portion of the carbon from the pig, prefer purging the
latter entirely of its carbon and other matters, by the expulsion of which it is
converted into malleable iron, (as already fully explained in the iron manufac-
tures;) and then giving the malleable iron that small dose of carbon by which
it is made into steel.
Natural Steel—In those countries where iron ores are found extremely rich
and pure, and their reduction is effected by charcoal, excellent steel is produced
from cast-iron, without an intermediate process; and this kind of steel has in
consequence received the distinguishing name of Natural Steel. Formerly, this
kind of steel was fabricated and chiefly used in this country, and it is still made
in Styria and Catalonia, with great success. The French some time ago
attempted the imitation, but notwithstanding some of their most scientific men
were engaged in the undertaking, they failed in obtaining a natural steel equal
to that which they imported from Germany. It had been previously asserted
by Bergmann, that the natural steel of the Styrian and Nassau Liegen foun-
dries, derived its excellence from containing a portion of manganese; and this
opinion was subsequently corroborated by a writer in the Annales de Chimie, who
had made some comparative analyses of the ores used in France and Germany.
In support of his opinion, he mentions the fact that in the territories of Nassau .
Liegen, there are mines of manganese, and that the black oxide of that metal is
employed as a flux in smelting iron intended for steel when their ores are found
to be naturally deficient of that substance. This writer states, that steel in
general, but particularly natural steel, is essentially an alloy of iron and manga-
nese, combined with carbon, and that this alloy is the natural steel of Germany,
generally in these proportions:—
Iron . . . . . . . . 96.84
Manganese . . . . . . 2.16
Carbon . . . . . . . [.00
I00.00
IRON. 785
Hence he concludes that good natural steel ought to contain twice as much
manganese as iron. Several years ago, the writer of this article (having a dif-
ferent object in view) mixed some black oxide of manganese with melted cast-
iron, and the result was an exceedingly hard alloy, resembling steel. For
obtaining natural steel, the ore is smelted, as for iron in blast furnaces; but the
blast given is weaker, and is directed not upon the metal, but in a horizontal
direction above it. The metal is kept covered with slag, and is not disturbed
by stirring. When the iron is judged to be sufficiently refined, and has
become nearly solid, it is taken out of the furnace and forged; after this,
natural steel is withdrawn, there remains at the bottom of the furnace one or
more pigs of cast-iron, rather hard, which are generally employed in fabricating
implements of husbandry. The natural steel of Germany is extensively em-
ployed on the continent in the making of files, and various sorts of tools. The
celebrated steel from Damascus, called damask steel, and that from Bombay,
called Wootz, are both natural steels, being converted directly from the ore in
crucibles. These “fancy steels,” however, we shall take some further notice of,
after having explained the more important operations of our manufacturers.
Blistered Steel.—The first process employed by our manufacturers in the pre-
paration of steel is to stratify malleable bar iron with pounded charcoal in alter-
nate layers, in a close furnace, to cause a gradual absorption of the carbon by
the metal. In the engraving on p. 786, Fig. 1 represents a vertical section of
the kind of furnace employed for this purpose; and Fig. 2 represents a plan of
the interior structure, without the external conical walls which surround it, a
and b are the troughs, called cementing pots, in which the bars of iron are laid to
be converted into steel; the pots are made of a peculiar kind of fire-stone, not
liable to crack or fuse; their dimensions are usually from 10 to 15 feet long,
and from 24 to 30 inches in width and depth. The bars of iron, and the pow-
dered charcoal are laid in the pots in alternate strata; the upper stratum of
bars being covered with a thicker layer of charcoal than those underneath; above
which is . laid a mixture of sand and clay, to prevent the charcoal from entering
into combustion by access of the outward air. c is the external cone, of strong
masonry or brickwork, of from 40 to 50 feet high. Inside this superstructure is
a smaller conical dome d, called the vault, which is built substantially of fire-brick,
or other material, capable of withstanding an intense heat. The vault rests upon
external walls e e, at a distance from those which support the external cone, and
the space between them is filled up with rubbish, sand, &c. The cementing pots
a and b are supported upon a series of detached courses of fire-brick, leaving
spaces or flues between them to conduct the flame under the pots. In the same
manner the sides of the pots are supported from the vertical walls of the vault,
and from each other by a few detached stones, so as to intercept the heat. The
vault has a series of short chimneys to conduct the smoke into the great cone
c, as shown at ff. In the front of the furnace, an aperture is made through
the external building, and another corresponding in the walls of the vault;
these openings form the door, at which a man enters the vault to put in or take
out the iron; but when the furnace is lighted, these doors are closed by fire-
bricks, luted with fire-clay. Each pot has also small openings at each end,
through which the ends of two or three bars are left projecting in such a manner
that, by only removing one loose brick from the external building, the bars can
be drawn out without disturbing the process, to examine the progress of the
conversion from time to time; these are called tap-holes, and should be placed
in the centre of the pots to obtain a fair specimen of their product. The fire-
grate is shown in Fig. 1 at g, consisting of bars laid over the ash-pit h, which
must have a free communication with the open air. The attendant examines
the state of the fire from the ash-pit h, which has steps leading down to it, and
when he perceives any part of the fire not very bright or fierce, he thrusts, a
long hooked bar through the grating, and opens a passage for the air. The
fire-place has no door, being built open at each end; but a quantity of coals is
piled up before each aperture, so as to close the openings, and answer effectually
the purposes of doors; from this heap of coals the workman shoves in, with a
kind of long hoe, such quantity as may be required to replenish the furnace
786 IRON,
from time to time, and the renewal of the coals to the heap prevents any air
entering the furnace, but such as has passed upwards through the ignited fuel,
and contributed to the combustion. The heat and flames from the fuel are
reverberated by the dome d, and have passages underneath and around the
pots. The degree of heat at which the carbon begins to be absorbed, is found
to be about 700 of Wedgwood's pyrometer; this heat is kept up for about
7 or 8 days, according to the thickness of the bars, and the degree of carboni-
zation required. When the process is completed, the furnace is suffered to
E.
filmurunnmuniſiſ:
Fig. 2.
cool, which takes 6 or 7 days more; the contents of the pots are removed, and
the fresh charges put in, the charcoal serving again, as it is scarcely altered
from not having entered into combustion. The bars of iron are now found to
be covered with blisters and projections, to have acquired a brittle quality, and
to exhibit in the fracture a crystalline structure, which is uniform throughout
the bar if the carbonization has been complete. The degree of carbonization
is varied according to the purposes for which the steel is intended; and so


IRON. 787
likewise is the nature and quality of the iron employed for the purpose. For
the finest and most important purposes, the Russian and Swedish irons are
always employed for conversion, by reputable manufacturers; and there are
certain kinds, of long-established celebrity, to which a very general preference
is given; these are distinguished by well-known marks stamped upon them,
which the governments of the countries whence they are imported warrant the
authenticity of Amongst the chief of these marks may be particularly men-
tioned L inside a circle (called hoop L); G, with an L connected to the bottom
of the G (called G L); two small circles (called double bullet); a G, and an F
underneath, connected to it (called G F); an ellipsis, with some lines across its
shortest diameter (called gridiron); J B, the J being made out of the upright
line of the B (called J B); a stag's head and antlers (called stein-buck); a
crown, with a C close underneath (called C and crown). Of course there are
as many marks as there are manufactories or mines, many of which may furnish
as good iron, but they are not yet so well established. There is, however, pro-
bably some exceptions to this remark, and undoubtedly the Russian iron, branded
CCM) D, is an exception. The hoop L, which is the produce of the Dannimora
mines, in Sweden, is considered the most valuable; forty pounds sterling per
ton being readily paid for it, which is about four times the price of the best
English bar iron. However immense this difference of cost to the steel
manufacturer, it is of trifling importance compared to that of maintaining his
reputation for the production of an unexceptionable article. The paying of
threepence per pound more for the raw material, will make no perceptible dif-
ference in the cost of the artist's graver, the surgeon's lancet, or even the
writer's pen-knife—not to mention watch springs, and a thousand other appli-
cations of fine steel, in which, were it necessary to insure perfection of quality,
a hundred times the cost of the raw material added to the manufactured article
would be gladly paid.
Mackintosh's Patent. — A few years ago Mr. Mackintosh, of Crossbaskets, in
Lanarkshire, took out a patent for converting malleable iron into steel, by sub-
jecting it to a stream of carburetted hydrogen gas, evolved from coal under dis-
tillation. The iron is inclosed in a pot or crucible in the furnace, and when
arrived at a proper heat, a stream of gas is directed by a pipe into the crucible,
which has another aperture to allow that part of the gas to escape which has not
been taken up by the metal. The apparatus for conducting this process will
of course admit of various modifications. This invention appears to have
reason for its basis; for it must be evident that in the process of cementation
before described, the carbon must have entered into combination in a gaseous
state with the iron : the steel made by it was reported to be excellent.
Whether experience has proved it to be an economical process, is a point upon
which we are not informed.
Mushat's Patent Steel.—The preceding articles are descriptive of three dis-
tinct modes of preparing steel. First, by the careful refinement of cast-iron;
second, by the stratification of malleable iron with charcoal; and third, by the
application of gaseous carbon to the metal. A fourth process, materially dif-
fering from those, but producing very similar results, and attended with some
peculiar advantages, was patented in the year 1800 by Mr. Mushat, the gen-
tleman whose metallurgical labours we have before noticed. The specification
of the patent directs that malleable iron (in scraps or bars) is to be put into a
crucible, together with a due proportion of powdered charcoal, or pit coal,
plumbago, or any other substance containing the carbonaceous principle, and
subjected to an intense heat in an air or blast furnace until the metal is reduced
to a fluid state, when it is to be poured out into moulds to form ingots, or any
other article that may be required; which castings will be of a similar nature
to the steel produced by cementation. But in those cases when iron ore can
be obtained sufficiently rich and free from foreign admixtures, the patentee pro-
poses to save all the time and expense attending the tedious operations neces-
sary for the conversion of such ore, first into cast-iron, and afterwards into bar
iron ; for such ore, he observes, being previously roasted or torrified, may be
substituted for the malleable iron, and the result will be cast-steel, provided
788 | RON.
the proper quantity of carbonaceous matter be used, as for the common
and ordinary qualities of cast steel. The quantity of carbonaceous matter
required, is much less than had been previously supposed to be necessary. In
employing wood charcoal, from a seventieth to a ninetieth of the weight of the
iron being sufficient; and when the quantity is increased beyond a seventieth
to a sixtieth, or a fortieth of the weight of the iron, the steel becomes so fusible
that it may be run into moulds of any shape, and afterwards be capable of
being filed and polished. Hence, by casting, may be constructed stoves, grates,
kitchen utensils, wheels, mill-work, and a great variety of things which could
not be so made by the processes previously in use. By varying the proportions of
the carbonaceous matter, he can make as great a variety in the qualities of the
steel, as the various kinds of pig-metal differ from each other. Cast-steel, made
in the ordinary way, Mr. Mushat observes, is so volatile when in fusion as not
to admit of being run into any shape except straight moulds of considerable
diameter; but that steel of such density as to admit of being cast into any form
may be produced by his process, by increasing the quantity of charcoal, and
fusing the matter as before directed. To produce qualities of steel softer than
is usually manufactured by the common processes, he uses a very small propor-
tion of charcoal, sometimes so little as a two-hundredth part of the weight of
the iron; and he states that steel produced with any proportion of charcoal not
exceeding the one-hundredth part, will generally be found to possess every
property requisite to its being cast into those shapes which require great elas-
ticity, strength, and solidity; and will also be generally found capable of sus-
taining a white heat, and of being welded together like malleable iron.
Tilted Steel.—As blistered steel in its crude state is applicable to but few
purposes, it is moderately heated in a furnace, and subjected to the action of a
tilt hammer, which strikes about 700 blows per minute : this operation increases
its tenacity and solidity, and adapts it to numerous uses.
Shear Steel.—This 11ame was given to a steel that was first made by Crowley,
of Newcastle, about sixty years ago, in imitation of a peculiar kind of bar
steel that we formerly imported from Germany. Crowley, however, stamped
his production with the figure of a pair of shears, to indicate its suitable
application. The process of making it at Sheffield, where the manufacture
of this and all other kinds of British steel is conducted on an immense scale, is
as follows:—The bars of blistered steel are broken into pieces of from one to
two feet in length, which are then piled up into bundles or faggots of a size
and weight adapted to their subsequent applications. The faggots are then taken
up by means of a long bar having a ring at the end, into which one extremity
of the faggot is inserted; and by means of the bar as a handle, a workman puts
it into a reverberatory furnace, whence, after it is brought to a welding heat, it
is taken out and placed under a heavy hammer, by which it is drawn out into
a bar; this bar is then divided, the pieces laid together, brought again to a
welding in the furnace, and then under the hammer, or by rolling, reduced to
the size required. By this process the steel has lost much of its previous brit-
tleness, and has acquired a uniform texture, which adapts it to the manufacture
of a great variety of edge tools and other purposes to which it was before
unsuited. Various qualities of shear steel are made, distinguished by the terms
half-shear, single-shear, and double-shear, according to the number of times it
has been cut, piled, welded, and drawn out.
Sanderson's Patent.—In September, 1828, a patent was taken out by Mr.
Charles Sanderson, of the Park Gate Iron Works, entitled “A new process or
method of making shear steel,” which, the specification informs us, consists
in forming shear steel out of very small pieces of bar steel, instead of
pieces from one to two feet in length, as heretofore, whereby he is enabled to
form shear steel with fewer heats, and consequently with less waste, and
without the use of silicious sand, as heretofore practised. The patentee describes
his mode of operation in the following words:—“I take bar steel in the state
in which it comes from the converting furnace, and break it into very small
pieces of one inch to two inches long; a quantity of these small pieces being
ready, I procure a round stone of any quality which is capable of withstanding
IRON. 789
the strong heat of a reverberatory furnace without cracking or breaking; and
upon this stone the small pieces are piled as closely and compactly as possible;
the whole is then inclosed in a fire-clay crucible, and placed in a reverberatory
furnace, where it is allowed to remain until the whole mass becomes of a high
welding heat. It is then taken from the crucible and placed under a heavy
cast-iron hammer, usually called a metal helve, and exactly the same as those
used in the manufacture of bar iron : this hammer is driven by machinery, and
from the circumstance of the whole mass being in a semi-fluid state, it is almost
instantaneously hammered or manufactured into one solid mass or bloom of
steel, of from three to four inches square; this bloom is placed in a furnace, or
as it is more generally termed, a hollow fire, of two or three feet square, heated
with coke, and the heat increased by the application of a blast of air; and the
whole mass or body of steel so hammered or manufactured as aforesaid, is
raised to a high welding heat; it is then taken from the furnace, and placed
under the same metal helve or hammer before mentioned, and drawn into a bar
of shear steel, ready to be tilted or rolled into the various sizes or shapes which
may be required. For shear steel, to be used for inferior purposes, it might be
too expensive to place the piled steel in a crucible, but it might merely be placed
i. a reverberatory furnace, and drawn thence, when it is of a complete welding
eat.”
Cast Steel.—The finest and very best steel for most purposes, is that which
has undergone the process of fusion and a subsequent hammering, called cast
steel. It is about ninety years since this steel was introduced by one Hunts-
man, of Attercliffe, near Sheffield, whose name it continued to bear for a long
time; but his rivals at Rotherham and Sheffield, who subsequently undertook
the manufacture, gave it the more significant name which it now bears. The
process of preparing it on the large scale, is as follows:–Blistered steel is
broken into small pieces, and put without any admixture into crucibles that
hold about 40 lbs. each, and are covered with a lid. The crucibles are sepa-
rately deposited in a row of small melting furnaces, which are usually square
pots, about 15 inches wide and 3 feet deep, with a grating at bottom ; the tops
of these furnaces are open, and level with the floor of the foundry; and just
below their tops are lateral apertures or flues, leading into the common chimney
of all the furnaces; access to the fire-places and ash-pits is had in a vault under-
neath. The fuel employed is hard coke, in which the crucibles are entirely
imbedded and covered over; then each of the furnace mouths is stopped with
a trap-door of fire-bricks, inclosed in an iron frame. This being done, a very
sharp draught of air is produced from the ash-pits, through the fuel, into the
lateral flues, and a very intense heat is produced, which, being kept up for four
or five hours, the steel is thereby brought into perfect fusion, when it becomes
necessary to remove the crucibles, and pour out their contents into cast-iron
ingot moulds, prepared for their reception, which are either in the form of a
short thick bar, for being tilted, or a thick flat cake, to be lamellated between
the rolls. The melter has likewise to prepare himself against the terrible ordeal
of the operation just mentioned : to protect himself from the fierce fire of the
furnaces, as he bends over their mouths, which would otherwise set his clothes
on fire, he puts on an armour of coarse sacking; and then, with a pair of long
iron tongs, he gripes the blazing crucible, and, quickly lifting it out of its
chamber, pours the contents into the moulds. The subsequent processes upon the
ingots, bars, or plates of steel, cast in the moulds to bring them to the required
shapes, are in every respect the same as we have described for preparing iron
into similar forms; but on account of the greater value of steel, and the delicate
manner in which it is often wrought, the rolling and hammering processes
become more essential in perfecting the quality, and therefore they are more
carefully performed. For the best purposes, steel is always preferred that has
been drawn to its required sizes under a tilt hammer, which gives three or four
hundred blows per minute. It is however deserving of remark, that when
steel rods and bars have been repeatedly rolled at a low heat, they acquire the
same density, and more uniformity, than tilted steel.
Needham's Patent.—A patent for a new process of casting steel was taken
Q H
790 IRON.
out in 1824, by Mr. Needham, of Davis-street, Fitzroy-square. His plan is to
employ large fixed or stationary crucibles (made of fire-stone, or Stourbridge
clay), and allowing the steel, when melted, to flow from them, through suitable
apertures made in the sides, into the moulds, instead of moving the melting-
pots already described. The size and shape of these stationary crucibles, it is
stated in the specification, may be varied according to circumstances, but a
preference is given to an oblong form, with movable covers, fixed upon bearers
of fire-brick or stone, on a plane a little inclined from the horizontal line; at
the bottom of each crucible a perforation is made, to which is fixed a tube, that
passes through the furnace to the moulds, with a plug at the external end; this
being withdrawn, the fluid metal readily discharges itself into the moulds. In
this manner several melting-pots may be fixed in one furnace, so that a quan-
tity may be fused sufficient for articles of great magnitude; and as the different
descriptions of steel require different degrees of heat for their fusion, the
patentee recommends that those which require the least be placed in crucibles
above those which require the most; by which arrangement, in casting large
shafts or cylinders of steel, those parts that require it may be formed with the
best steel, while those parts wherein an inferior steel answers the purpose, may,
in like manner, be supplied with it. If it be required to cast a large cylindrical
steel roller, the exterior may be made of a superior quality of steel, and the
interior of a common quality, by placing a cylinder of wrought iron within
the hollow cylindrical mould; and then directing jets of fluid steel, of distinct
qualities, to flow into the opposite sides of this circular wrought-iron partition;
the steel will then adhere to the iron, and form one solid roller, of inferior cost,
but equal in quality to one made entirely of superior steel.
Thompson's Patent.—A short time after the granting of Mr. Needham's
patent, Mr. Thompson, of the Chelsea-street Works, took out another, having
a very similar object in view. He proposes, in the first place, to melt the steel
in a reverberating or puddling furnace, by which pit-coal may be used instead
of coke; secondly, instead of the movable crucibles in general use, he employs
stationary vessels, made of the usual materials, but of a semi-cylindrical shape,
having spherical ends, and a rebate or groove in the upper edges, to fit a cover
to it. These are to be fixed on a slightly-inclined plane, for the convenience
of the fluid discharging itself through a hole in the bottom, in which is inserted
a tube of platina; this tube is connected to another tube of fire-clay, passing
through the brick-work to the outside of the furnace, through which the metal
flows into moulds, through apertures previously stopped with clay, which are
tapped by means of a long rod tipped with platina.
Alloys of Steel—Messrs. Farraday and Stodart, a few years since, made a
series of experiments on the combinations of some other metals with steel, an
account of which was published by them in the Philosophical Transactions for
1822; amongst the results of these experiments the following appear to be most
worthy of notice. Silver can be alloyed with steel only to the extent of a five-
hundredth part; when more was used, it either evaporated, or separated as the
button cooled, or was forced out in forging. The alloy was said to be excellent;
and the addition of price was no obstacle to its use for fine instruments.
Steel, alloyed with one-hundredth part of platinum, though not so hard as the
silver alloy, has more toughness; where tenacity as well as hardness is required,
the extra cost was considered to be more than counterbalanced by its excellence.
As far as the experimenters could judge, neither gold, tin, nor copper, improved
steel. Messrs. Stodart and Farraday's memoir on this subject having been
noticed in the public journals, some of our Sheffield manufacturers wisely con-
sidered that it afforded them a favourable opportunity to advertise themselves to
the public, along with their wares made of “silver-steel; ” and, for a while,
knives and scissars, exquisitely finished, made of that “invaluable” alloy, were
alone the fashion. Rival manufacturers sought in turn to amuse the public
with Wootz, and Damascus, and Peruvian steel; and each of these were, for a
time, necessary to the novelty-loving part of the public. Time had, however,
swept nearly all the notices of these wonders of the day from our shop windows,
and old-fashioned steel was quietly resuming its sway, when suddenly meteor
IRON. 791
steel made its appearance, not from the clouds, nor the moon, nor from a
volcano, but from the patent office, as will appear from the subjoined account
of the enrolled specification. -
Meteor Steel.-The patentees of this manufacture (Messrs. J. Martineau, jun.
and W. H. Smith,) specify their object to be the preparation of an alloy of steel,
having that peculiar wavy appearance exhibited in the Damascus sword blades,
and likewise for producing their toughness and elasticity of temper. The process
of preparing the alloy is thus described: zinc 80 parts, purified nickel 16 parts,
silver 4 parts = 100 parts. These are put into a black lead crucible, and
covered with charcoal; the lid is then luted down to prevent evaporation, and
exposed to the heat of an ordinary steel furnace, until the metals are fused,
when the alloy is poured out into cold water, to suddenly cool it, which renders
it so brittle, that it is easily reduced afterwards, by a pestle and mortar, to
powder, which the patentees call meteor powder, and is incorporated with the
steel, together with other mixtures, in the manner following: 28lbs. of common
blistered steel, 10 oz. of meteor powder, 7 oz. of powdered chromate of iron,
1 oz. of charcoal, 2 oz. of quick-lime, and 3 oz. of porcelain clay, are put
together in a crucible, and fused in a cast-steel furnace. After casting, this
alloy is to be drawn out, under a hammer, into bars, when it will be found to
exhibit the damask wavy appearance on its surface. To bring out the damask
more fully upon any article made of this alloy, the surface is to be polished, and
then washed over with nitric acid, diluted with nineteen times its weight of
water. It could hardly have been supposed by the patentees that such a
variety of substances was necessary to producing the damask pattern upon
steel; the nickel and the chromium were probably introduced by them with the
view of imitating those natural phenomona called meteoric stones, in which it is
said one or both of these metals are constantly found: and as two or three of the
other ingredients of this patent steel mixture may be regarded as fluxes, it is not
quite so whimsical a compound as it might at first appear, especially as it was
introduced at a time when the public taste for steel-extraordinary was so much
excited.
Wootz.-This celebrated steel is made in India, at little furnaces supplied
with air by several pairs of small bellows, worked assiduously by men and
boys; and thus is produced the raw material of the famed Damascus sword
blades, the various patterns upon which have been imitated in our linen manu-
facture, and hence called damask. To ascertain the cause of this beautiful
appearance has given rise to a good deal of investigation, and several of our
chemists, as well as others on the continent, have entered upon the inquiry.
The wootz imported from Bombay is in form of a round cake about 2 lbs. weight.
Dr. Pearson, in an essay published many years ago in the Philosophical
Transactions, Vol. XVII., gave it as his opinion that it is made direct from the
ore, and, consequently, that it has never been in the state of wrought iron.
“For the cake,” he says, “is evidently a mass which has been fused; and the
grain of the fracture is what I have never seen in cement steel before it is
hammered or melted.” This opinion consists with the composition of wootz;
for it is obvious that a small portion of oxide of iron might escape metal-
lization, and be melted with the rest of the matter. The cakes appear to have
been cut almost through, while white hot, at the place where wootz is manu-
factured; and as it is not probable that it is then plunged in cold water, the
great hardness of the pieces imported above that of our steel must be imputed
to its containing oxide, and, consequently, oxygen. The particular uses to
which wootz may be applied may be inferred from the preceding account of its
properties and composition. A very general opinion is, that the waved appear-
ance is produced by an intermixture of steel and iron forged together, an
opinion that is in some degree founded upon experiment, as very close resem-
blances have been made by that process. Many sword blades, in no respect
inferior to the Eastern originals, have been fabricated in the dominions of
Austria and Prussia, by a process invented by Professor Crevilli, who had
given detailed, instructions for their manufacture in a small treatise published
at Milan, and entitled, Memoria Sull'Arte di fabbricare le Sciabole di Damasco.
792 IRON.
*
An epitome of Crevilli's treatise was published in the Allgemaine Militar
Zeitung, the following translation of which was given in a recent number of the
United Service Journal. “A long flat piece of malleable steel, of about one
inch and a half in breadth, and one-eighth in thickness, is to be first bound
with iron wire, at intervals of one-third of an inch. The iron and steel are
to be then incorporated by welding, and repeated additions (10 or 20) of iron
wire made to the first portion, with which they must be firmly amalgamated.
This compound material is then to be stretched and divided into shorter lengths,
to which, by the usual process of welding, grinding, and tempering, any wished-
for form may be given. By filing semicircular grooves into both sides of the
blade, and again subjecting it to the hammer, a beautiful roset-shaped Damascus
is obtained: the material can be made to assume any other form. The solution
by which the figures are made visible, is the usual one of aquafortis and vinegar.
The success of this method, and the excellence of the blades which have been
constructed according to these directions, have, by various trials, been placed
beyond all doubt. Professor Crevilli has had several sabre blades prepared
under his own instruction at Milan; similar experiments have, by the Emperor's
commands, been made at the Polytechnical Institution at Vienna; and finally,
the War Office has empowered Daniel Fischar, manufacturer of small arms in
that capital, to proceed with the manufacture on a large scale. These blades,
which, when made in large quantities, are but little dearer than those in common
use, have been submitted to the severest tests. . . . . An idea of their extra-
ordinary tenacity may be formed from the fact, that out of 210 blades that
were examined by a military commission, and each of which was required to
bear three cuts against iron, and two against a flat wooden table, not a single
one snapped, or had its edge indented. In Prussia this method of preparing
sword blades is stated to have been in practice several years, and to have been
attended with equal success.” M. Breant, examiner-general of assays at the
Royal Mint of Paris, investigated the nature and composition of wootz very
philosophically. In an interesting memoir which he published on this subject,
he observes, that if in the preparation of ordinary steel sufficient carbon has
not entered, the steel formed will only be in proportion to the quantity of
combined carbon, the rest will be iron, only mixed. The cooling then takes
place slowly, the more fusible particles of steel will tend to unite together and
separate themselves from the portion of iron. This alloy will therefore be
capable of developing a damask, but this damask will be white, and slightly
marked, and the metal will not be susceptible of great hardness, because it will
be mixed with iron. If the proportion of charcoal be exactly such as it ought
to be in order to convert the whole of the iron into steel, there will be only
one sort of combination; but if the carbon is a little in excess, the whole of the
iron will in the first place be converted into steel, afterwards the carbon remaining
in the crucible will combine in a new proportion with the part of the steel already
formed. There will in this case be two distinct compounds, namely pure steel,
and carburetted steel, or cast-iron. These two compounds, at first mixed con-
fusedly, will tend to separate when the liquid matter remains at rest. A
crystallization will then form, in which the particles of the two compounds
will arrange themselves according to their respective affinity or specific gravity.
If a blade made of this steel be put into acidulated water, a very apparent
damask will be developed, in which the pure steel parts will be black, and those
of carburetted steel will remain white. The carbon irregularly dispersed in the
metal, and forming two distinct combinations, is, then, that which occasions the
damask; and it is obvious that the slower the cooling, the larger the veins of
the damask should be.
“Plumbago,” says M. Breant, “has appeared to me in some circumstances to
soften the steel, which an excess of carbon would render too harsh; at least I
have obtained excellent results with a hundred parts of steel, one of smoke-
black, and one of plumbago. But a very remarkable experiment in regard to
the advantage which may be derived from it, in working on a large scale, is,
that a hundred parts of soft iron, and two of smoke-black, melt as easily as com-
mon steel.” From this announcement by M. Breant, it appears, that he was
IRON. 793
unacquainted with Mr. Mushat's patent process of converting malleable iron into
steel by fusion with charcoal, described at page 787. M. Breant continues, “It
must be supposed that the whole of the carbon does not enter into combination.
Some of our best blades are the product of this combination. It is evident from
this experiment that it is not necessary, in order to obtain very good steel, to
begin the operation by cementation with iron. The iron may be treated
immediately with the smoke-black, and this would greatly diminish the
expense of the manufacture. A hundred parts of the filings of very grey
cast-iron, and a hundred parts of similar filings previously oxidized, have pro-
duced a steel of a fine damask, and fit for the manufacture of bright arms;
it is remarkable for its elasticity, a quality not possessed by the Indian steel.
The more carbon the steel contains, the more difficult it is to forge. Most
of the specimens that I have prepared have not been drawn out, but at a
temperature the limits of which are extremely confined.” “I am convinced
from experience, that the orbicular veins called ronces by the workman, which
are seen on fine oriental blades, are the result of the manner of forging. If
we content ourselves with drawing the steel out lengthwise, the veins will be
longitudinal; if we extend it equally in all directions, the damask has a crys-
talline appearance. If we render it wavy in the two directions, there will be
shades and gradations as in the oriental damask. It will not require long trials.
to produce any variegated design we desire.”—Repertory of Arts.
Having explained the most approved modes of preparing the celebrated
damasked steel, as well as the various steels of our now no less celebrated British
manufacturers, we proceed to the consideration of another department of the
subject.
Case-hardening.—This is a process for converting the surface only of articles
made of malleable iron into steel, in order that they may afterwards receive a
high polish. The process is extensively applied to the pokers, tongs, and
shovels of our domestic fire-grates, and to an infinite variety of our iron manu-
factures. The following mode, recommended by Mr. Gill, editor of the Techno-
logical Repository, deserves confidence, from the extensive practical knowledge
of that gentleman in the treatment of iron and steel. This is effected, he says,
by inclosing the articles in carbonaceous compounds, either animal or vegetable,
and exposing them to heat in close vessels, until the change is completed, and
until the surface at least of the articles is converted into steel. For this pur-
pose, bones, from which the ammonia has been extracted by distillation at a high
temperature, and which are afterwards ground to a coarse black powder, are
chiefly used. The articles being surrounded with this powder, contained in cast-
iron vessels, are exposed to a high red heat, in an open fire-place, for several hours,
until the surfaces of the iron articles are sufficiently changed to steel; when, if
large enough, they may be taken out, whilst hot, and quenched in water, or if
too small and numerous, the whole contents of the vessel, bone-dust and all,
may be poured into the water. Any parts of the articles which are required to
remain iron after this operation, may be guarded from the action of the carbon,
by coating them with clay or loam. Sometimes the water is covered with a
layer of oil, two or three inches in depth, to prevent the small steel articles
from being cracked in quenching; and it is very convenient in this case to
have a wire sieve suspended in the water, at a proper depth beneath its surface,
to suffer the bone ashes to fall through, but to detain the smail articles. Other
substances are employed in case-hardening; leather, burnt till it can be pulve-
rised, is considered a good agent; also the hoofs and horns of animals, heated
in an oven until they can be beaten to a coarse powder: the latter are preferred
by gunsmiths for their work.
Hardening and Tempering.—In giving the requisite degree of hardness to cut-
ting instruments of steel, two distinct processes are employed; first, hardening,
and afterwards tempering. The hardening is effected by heating the steel to a
cherry-red, and immediately plunging it into cold water; by this process, the
steel becomes so hard as to resist, or turn the edge of the hardest file; likewise
so brittle as to be useless for most purposes, but particularly for cutting instru-
ments. To adapt the steel to the latter, the second process, called tempering,
794 IRON.
is resorted to, which is a species of annealing, or softening, or as the workmen
term it, letting down, to the degree of hardness which is necessary for the peculiar
purpose for which it is designed; for in proportion as the edge is harder
than is required, is its liability to break in use. It is a remarkable fact, that
the greatest part of our ordinary cutlery is hardened by a process which,
although well known to be a very defective one, is persisted in from the force of
habit, or from an indisposition in the workman to make any changes in the cus-
tomary routine of executing work, in which the remunerating prices are very
low. We allude in particular to the practice (which, we are informed, is general
at Sheffield,) of hardening direct from the anvil; that is, the articles are hard-
ened with the scale on the surface, which is produced by the act of forging.
The scale varies in thickness, according to the degree of heat the steel received
in forging; it is also a very bad conductor of heat, consequently the transition
from heat to cold (by which the effect of hardening is produced) is not so
sudden in one piece of steel as in another; and some are scarcely hardened at
all, owing to the temperature of the water having scarcely penetrated through
the scale. Hence, when such articles are afterwards tempered or “lowered,”
there are not two alike in temper out of a great number; a fact which can
hardly have escaped the observation of any man who has shaved for several
years. Instead, therefore, of the customary mode of hardening the blade
direct from the anvil, it has been recommended by an experienced manufac-
turer, that the blades be passed from the anvil to the grindstone. “A slight
application of the stone,” he observes, “will remove the whole of the scale or
coating, and the razor will then be properly prepared to undergo the operation
of hardening with advantage. It will be easily ascertained that steel in this
state heats in the fire with great regularity, and that when immersed, the
obstacles being removed to the immediate action of the water on the body of the
steel, the latter becomes equally hard from one extremity to the other. To
this may be added, that as the lowest possible heat at which steel becomes hard
is indubitably the best, the mode here recommended will be found the only
one by which the process of hardening can be effected with a less portion than
is or can be required in any other way.”
Considerable difficulty has been experienced in giving to articles about to be
hardened a perfectly uniform degree of heat in an ordinary fire; and one of
the best means of obviating it is probably that which has been published by
Mr. Nicholson, of his adoption, and which he had for some time previous, for
justifiable reasons, kept secret: this was to employ a bath of melted lead,
heated to moderate redness, and well stirred; into this the piece was plunged
for a few seconds, until, when brought near to the surface, that part did not
appear less luminous than the rest. The piece was then speedily stirred in the
bath, suddenly drawn out, and plunged into a large body of water. Instead of
employing simple water as the cooling medium, a variety of salts added to it
have been at different times recommended and boasted of. Not long ago,
mercury was cried up, and just now it is the fashion to extol a current of air,
grounded, we believe, on the report of travellers, that the sabres of Damascus
are hardened by cleaving the north wind with them. Although it is probable
that improvements in the present mode of hardening may be discovered, we
think it is improbable that they will be found in that fluid which is an inferior
conductor of heat, and that cannot be applied with equal uniformity to water.
A mode of tempering instruments of hardened steel was invented by
Mr. Hartley, in 1789, for which he obtained a patent; and we have never yet
heard of a better. Mr. Hartley's plan was to immerse the articles in a bath of
oil, heated to a regulated temperature, and measured by a thermometer. This
was certainly a very great improvement, both in point of precision and dispatch,
on the common method of heating the instrument over a flame till a certain
colour, produced by a film of oxide, appears on its surface. These colours are–
At 4300 Fah. a very faint yellow, for lancets.
450° ,, a pale straw colour, for razors, and surgeons' instruments.
470° ,, a full yellow,-for penknives.
IRON. 795
At 490° Fahr. a brown colour, for scissors and chisels for cutting old iron.
510° ,, a brown, with purple spots, for axes and plane irons.
530° ,, a purple, for table-knives and large shears.
550° ,, a bright blue, for swords, watch springs, truss springs, and
bell springs.
560° ,, a full blue, for small fine saws, daggers, &c.
600° , a dark blue, verging on black–is the softest of all the gra-
dations, when the metal becomes fit only for hand and
pit-saws, which must be soft, that their teeth may bear
sharpening by the file, and bending or “setting.”
If the steel be heated still further, it becomes perfectly soft. When tools having
a thick back and thin edge, like penknives, are to be tempered, they are some-
times placed with their backs in a plate of hot iron, or on hot sand; otherwise
they would become too soft at their cutting edges before their backs would be
sufficiently heated. It is evident that baths of any of the soft metals, whose
fusible points are above those required for tempering, may be used instead of
oil; and alloys of those metals might be so proportioned as to obtain points of
fusion at the exact degree of heat required. In these cases, however, to prevent
oxidation, it would be necessary to keep the fluid metal covered with grease, and
it would be advisable not to omit the use of a thermometer. Mr. Gill, in the
Technological Repository, has recommended several compositions for hardening
and tempering steel, to which work we must refer the reader for the formulae
and processes. We do not insert them here, because they are, for the most
part, apparently unsuited to operations on the great scale, although they are
certainly, in many respects, well deserving the attention of engineers. We shall,
however, avail ourselves of his instructions in the following article.
On restoring the Elasticity of hardened and tempered Steel Articles.—“Saws,
sword-blades, clock and watch springs, &c., which, after being hardened and tem-
pered, require to be ground and polished, or otherwise brightened, lose their elas-
ticity or springiness by these operations, so as to appear soft on bending them,
although they are as hard as ever; these qualities are again restored to them,
either by heating over a clear fire, made of cinders urged by bellows, or over
the flame of burning alcohol, or by inclosing them in a smouldering fire, made
of wood-ashes and embers, to a blue colour, which colour may either remain,
or be removed by the application of diluted muriatic acid wiped over them.”
The partial Conversion of Iron into Steel, which is often the case in the blistered
bars, owing to the carbon not having penetrated to the middle, is usually
regarded as a great defect; but an important advantage may be gained from
it in the steeling of edge-tools, which, Mr. Gill says, is adopted by Mr. Maudsley.
The bar is split down its middle into two parts, and these parts are sometimes
subdivided; the internal parts which remain unconverted are then welded to
the iron of the tool, leaving the steel outside, to form the cutting edges of the
tool.
TABLE,-Showing the Weight of Cast-iron Plates, twelve inches wide, and from
one-eighth of an inch to one inch thick.

PARTS OF AN IN CH IN THICKN ESS.
|
Width
in
Inches.
#
#
§
§
§ One Inch.
3.
4.
lbs. Oz. lbs. oz. lbs. Oz. lbs. oz. b. oz. lbs. oz. lbs. oz. lbs. oz.
12 || 4 133| 9 10; 14 8 19 5; 24 24; 29 0 || 33 133 38 103
796
IRON.
TABLE,-Showing the Weight of one Foot Length of Malleable Iron.

SQUARE IRON. ROUND IRON.
Scantling. Weight. Diameter. | Circumference.
Inches. Pounds. Inches. Y. * Inches. W. º
# 0.21 # O. 16 1 0.26
§ 0.47 § 0.37 1} 0.41
# 0.84 # 0.66 1; 0.59
§ 1.34 " ; 1.03 1% 0.82
# 1.89 # 1.48 2 1.05
# 2.57 # 2.02 2} 1.34
1 3.36 1 2.63 2} 1.65
1} 4.25 l, 3.33 2# 2.01
1% 5.25 l; 4.12 3 2.37
13 6.35 l; 4.98 3} 2.79
1} 7.56 1% 5.93 3% 3.24
1; 8.87 1; 6.96 3# 3.69
1} 10.29 13 8.08 4 4.23
1; I 1.81 1% 9.27 4; 5.35
2 13.44 2 10.55 5 6.61
2} 17.01 2} 13.35 5% 7.99
2% 21.00 2} 16.48 6 9.51
2# 25.41 2} 19.95 6% 11.18
3 30.24 3 23.73 7 12.96
3% 41.16 34 27.85 7% 14.78
4 53.76 3} 32.32 8 16.92
4} 68.04. 3# 37.09 8% 19,21
5 84.00 4 42.21 9 21.53
6 I 20.96 4} 53.41 10 26.43
7 164.64 5 65.93 11 31.99
END OF WOL. I.
R. CLA Y, PRINTER, BREAD-STREET HILL.
✉
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