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PRACTICAL 'I‘REATISE

Gas = ﬂight:

zA SUMMARY DESCRIPTION
or THE

‘APPAJRATUS‘AND MACHINERY

BEST CALCULAT I'D FOR

IILLlZAIlALdQTENT?
STREETS, HOUSES, AND MANUFACTORlES,

WITH

QIarhuretteu ibpnmgcn, .Ut Qliuabcﬂiaz:
WITH REMARKS

ON THE UTILITY, SAFETY, AND GENERAL NATURE OF THIS NEW BRANCH
OF CIVIL ECONOMY.

 

BY FREDRICK ACCUM’,
OPERATIVE CHEMIST,

Lecturer on Practical Claemistry, on Mineraloo , and on CLemiﬂvy
applied to the Arts and Mamfaetures; Member of the Royal
Irish Academy, Fellow qf the Linmean Society, Member/f
the Royal Academy of Sciences (3f Berlin, érc. é'c.

 

WITH SEVEN COLORED PLATES.

 

FOL RTH EDITION.

 

L 0 ND 0 N:
Printed by H". Clawes, Northumberland Court ;
FOR R. ACKERMANN, 101, STRAND:

LONGMAN, nunsr, arms, ORME, AND BROWN ; AND snsnwooo, NEELY
mm JONES, pu‘mmosmn ROW; AND J. HATCHARD, PICCADILLY.

PRICE TIVELVE SIIILLINGS, IN BOARDS.

 

1818

 

U ' ~(5

9 ' .
' W \' .x_ ‘
'° A‘.

 

 

PREFACE.

 

ll, Compton-Street, Soho.

THE following pages are intended to exhibit a
summary view of the new art of procuring light, by
means of carburetted hydrogen gas, obtained from
pit-coal, and which of late has been employed with
unparalleled success,as a substitute for candles and
lamps, and is known by the name of GASfLIGHT.

To accomplish this object, I have given, in the
ﬁrstipart of this Essay, a concise and p0pular View
of the chemical theory and production of artiﬁcial
light—J have explained the action of candles and
lamps—J have shown the methods of measuring
the comparative illuminating power of artiﬁcial
light - of different kinds, so as to appreciate their
economical value—I have stated the proportions

of combustible materials requisite for producing

a light of a certain strength; with such other pre- ,

liminary facts and observations as were deemed
necessary to enable the reader to understand fully
the nature of the new art of illumination, which
it is the object of this Essay to describe.

These positions are followed by a chemical view

gym»;
(7;; {

 

iv . PREFACE.

of the general nature and composition of (Seal—-
the chemical changes which this substance suf-
('81s, when employed in the production of gas;
light—the different products it. fulnishesﬁthe
modes of obtaining them—their properties and
applications in the various arts of life.

I have given a description of the apparatus and
machinery by means of which the coal-gas is pre-
pared, and the methods employed for distributing
and applying it as a substitute for candles and
lamps, to illuminate houses, streets, and manufac-
tories :——I have furnished the data for calculating
the expense that must attend the application of
this species of light under different circumstances,
so as to determine the relative cost or value of
gas~lights, when compared with the lights now in
use—together with such other practical directions
and facts as will enable the reader to form a proper
estimate of the gas-light illumination, and to put

this art into practice.
1 have stated the leadmo objects of public and

private utility to which the new system of lighting
may be successfully applied, candidly pointing out
those in which it cannot be made use of to ad-
vantage

PREFACE. V

I have detailed the most obvious effects which
the discovery of lighting with coal-gas must ine-
vitably produce upon the arts and upon domestic
.econOmy; its primary advantages—its views—its
limits, and the resources it presents to industry and
public economy. I have endeavoured to shew how
far its application is safe, and in what respect it is
entitled to public approbation and national en-
couragement. ’

It may not be improper, before concluding, to in-
form the reader, that my qualiﬁcations for the task
I have undertaken, are founded upon many years
experience, during which time, I possessed peculiar
opportunities to Witness and verify the most ex-
tended series of operations that ever have been
made for the purpose of ascertaining the practica-
bility, safety, and general nature of the art of apply—
ing coal—gas as a substitute for tallow and oil; and
which have, as it were, ﬁxed the fate of this art.
The numerous experiments I instituted, upon a large
scale, by desire of the Gas-Light Company, for the
purpose of adducing them in my evidence before
the House of Commons, and House of Lords, on
a former occas10n, have enabled me to collect such

information as could not have been obtained by

vi PREFACE.

other means. The substance of these results
(which are printed by order of Government) are in-
corporated in this Treatise, together with such other
facts and observations as have presented them-
selves in the routine of my profession elsewhere.
To generalize the results of my observations, and
to make them practically useful to the public, is the
aim of the present publication, and I need scarcely
add, that their suﬂ'rages to the zeal and industry,
at least, with which I have endeavoured to attain

my object, will be a source of inﬁnite satisfaction.

FREDRICK ACCUM.

ADVERTISEMENT

TO THE SECOND EDITION.

 

ll, Compton Street, Soho.

Encouraged by the rapid sale of the First Edi-
tion of this Treatise, which was disposed of in less
than four Months, the Publisher is induced to re-
print the Work, which I herewith present to the
reader.

The public sanction with which the Treatise
has been honoured, and the private thanks which I
have received from diﬂ’erent Proprietors of large —
Establishments, who have successfully put into prac-
tice, by means, (f this Treatise, the Art on which
it treats, are ﬂattering testimonies that the work
has proved useful.

The reader need not be informed that the pro-
gress of the net-z: mode of procuring and distri-
butingLight, has, within these six months, been
uncommonly rapid. A large part of this metropolis
is illuminated with Gas-Light, more than 4000

viii ADVERTISEMENT

. Argand’s lamps now burn coal-gas, in this metro-
polis, and arrangements are making to extend
rapidly the application of the new lights with a
zeal and industry which does signal honor to the
promoters of the Gas-Light illumination. The
total length of main pipes deposited in the Streets
of London, for conveying carburetted hydrogen
gas, exceeds twenty-six miles.

It is obvious that an art so entirely new, must
naturally be in a progressive state of improvement.
Indeed, several alterations have been made in the
present structure of the Gas-Light machinery, and
new plans for preparing, purifying, and apply-
ing coal-gas have been projected. A revolving gas-
ometer constructed on the principle of the hydrosta-
tic bellows, has been adopted by JD. Clegg, of
London, and .new modes of purifying coal-gas, and
of economising fuel in the production of it, have
been pointed out by Mr. John Grafton, (late pupil
of Mr. Clegg of ﬂIanc/iester, and are now carrying
into eﬂect under his direction, in the lighting up
of the town of Preston, in Lancashire. I do not,
however, feel myself warranted to speak on the pre-
sent occasion with conﬁdence, on the general nature
and merits of any of the alterations which have
been made by ingenious and scientiﬁc men: be-
cause they have not yet been brought fairly into
action, nor have they stood the test of experience to ,

ADVERTISEMENT. ix

, warrant their superiority over the methods now
successfully employed in this town, wed in numerous
manufactories. By my present forbearance, there-
fore, I trust I shall lceep up the character for
fairness and impartiality with which the First
Edition of this Treatise has been honoured; yet
the reader may rest assured that I shall not fail
hereafter to lay before the public all those improve-
ments, which time and practice shall have proved to
be superior to the methods now in use.

Some new matter will nevertheless be found in
the present edition of the work. With regard to
the economy of fuel in particular, I have given a
concise popular chemical view of the natural his-
tory of the various kinds of Pit-Coal met with
in the London market. I have explained the na«
ture of their varieties—their diﬁ'Mrences, and com-
parative economical value. I have pointed out the
sort of coal best calculated for domestic and culinary
purposes. I have adverted to the bad construction
of grates, as well as to the great waste ofﬁiel in
ordinary open ﬁre-places. I have shown the means
of preventing that waste, together with the best
construction of ﬁre—places designed for general
domestic purposes, and I have also added [some
observations and hints relative to the nefarious
practices too commonly resorted to in the coal-
trade.

X ADVERTISEMENT.

Under these considerations I ﬂatter myself
the work will not be unacceptable to the public.
And I have once more to assure my readers that I
am still actuated only by the wish of promoting
public and private utility, and that I have no in-
terest either direct or indirect, in any Gas-Light
establishment whatever, nor in any branch of em-
ploy connected with this art.

FREDRICK ACCUM.

’

London, November.
1815.

PREFACE

TO

THE FOURTH EDITION.

 

IN the lines preﬁxed to the Third Edition of
this Treatise, the reader is informed that it
was my intention to lay before the public,in a
future Edition, certain improvements which
have been proposed by different individuals; in
the construction of the Gas-Light Machinery ;

but as four Months have scarcely elapsed,

PREFACE

since this promise was made, and a new Edi.
(ion of this Treatise being demanded, I do
not yet feel myself justiﬁed to speak on the
present occasion with conﬁdence on the im-
provements under consideration. I have not
had sufﬁcient opportunity to become convinced
of their practical superiority, and I trust, there-
fore, that I Shall not be censured‘ on that ac-
count; but I shall not fail hereafter, to fulﬁl
the promise in laying before the public all
those alterations which have been proposed
by ingenious men in the construction of the
Gas-Light Apparatus, when time and expe-
rience shall have established their superiority

over the methods new in use.

I have carefully revised this Fourth Edition
of the Treatise; the typographical errors of

the preceding Edition have been corrected;

PREFACE;

some slight alterations have been made in
several places, and I ﬂatter myself, that What
has been done, as far as it goes, will not be

considered as altogether superﬂuous.

FREDRICK ACCUM.

ll, Compton Street, Soho.

Lmulzm, April mm, ‘

ms. (/54 3 Sb/

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REVIEWS OF THE.FIRST EDITION OF

ACCUM’S

PRACTICAL TREATISE ON

'.

. ‘.\

GAS-LIGHT.

“ OUR limits will not allow us to speak in detail of the
merits of this Work. The abilities of the Author have
been long known, as a Philosophical and Practical Che-
mist. In the present work he has di5played much can-
dour and impartiality, and knowledge of the subject on
which it treats. His book will be found highly useful to
those who wish to acquire a practical knowledge of the
subject on which it treats, and will enable mechanics to
erect the apparatus necessary for carrying the Gas-light
illumination into effect—And it will give to those who
are unacquainted with the nature of the Gas-light illumi-

nation, a fair, and not over charged, statement of the

o.

‘ merits and defects of this new art; whilst at the same
time, the chemist will meet with facts relating to the sub-

'I

‘ ject of the Gas-light illumination, which will- arrest his

a

‘ attention and add to the general stock of chemical know-

ledge.

“

“ Philosophical Magazine, May, 1815. p. 373.

“ This Work contains a perspicuous and popular view
of the subject, and may be of considerable utility to
those who, without being acquainted with chemistry,
wish to have some general notion of the nature of Gas-
“ light.

“

“' ﬂnvnals of Philosophy, Sep. 1815. p. 2283‘

 

This Day is Publislzed, Price ls.i6d.

A Descriptive Catalogue of the Apparatus and Instru-
ments employed in Experimental and Operative Chemistry,
in Analytical Mineralogy, and in the pursuits of the recent
discoveries of Electro—Chemical Science: with directions
for ﬁtting up Laboratories for Philosophical Chemistry, and
a list of those Chemical Preparations which are indispen-
sable for the modern practice and general study of Chemi—
cal Philosophy. Manufactured and Sold by ACCUlVI
and GARDEN, Operative Chemists, Compton-Street,
Soho, London.

 

   
 
   
  
 
 

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CONTENTS. 1

 

Page
Introductory Observation. 1

Pnocness of the arts.——Inﬂucnce of it upon the morals and condition
of mam—Beneﬁcial tendency of chemical and mechanical
improvements.——Highest cultivation and reﬁnement—How ef-
fected—State of pre—eminence of people with regard to civiliza-
tion.—-and to be estimated—Flourishing state of those nations
which have shown the greatest activity in cultivating the useful
arts, and establishing useful enterprises—Nations are ﬂourishing in
proportion to their activity, with regard to the introduction of new
channels of industry.——-Which gives rise to barter or exchange.—
Subdivision of labour.-Great beneﬁt of it.———General observations
on this subject.—-Extraordinary discoveries of modern times.—
Artiﬁcial production of light—Importance of this art—It has not
hitherto attained the extent of its possible perfection—Scheme of ‘
lighting houses, streets, and apartments with coal-gas.———In what
respect it is entitled to examination and_ support—New art of pro-
curing lig'ht.—Art of printing.——Navigation.——Gunpowder.—'-The
diving bell.—./Erostation.——Electricity.——The steam engine—Have
changed the course of human affairs—Object of the treatise.

 

P A R T I.
Theory of the Production of Artiﬁcial Light.
8

Production of the ﬂame generated during the combustion of certain

bodies—In what it consists—Characters of ﬂame when perfect.—- ,
Most luminous ﬂame, how produced with the least consumption of \
combustible matter.—~Conditions necessary for that purpose—Im-
portance of this subject, with regard to the production and supply
of artiﬁcial light—Origin of the light of ﬂaming bodies.———Opinions
on this subject—.The ﬂame of bodies may be tinged—Blue ﬂame,
red ﬂame, green ﬂame, 8w.

 

xii \ CONT INTS.

Theory of the Action of Candles and Lamps.
Page 12

Action of the instruments of illumination—Rude method of procu-
ring light employed in some countries—Chemical action of can-
dles and lamps—Agency of the tallow, oil, &c.—Oﬂice of the
wick—It is the ﬁre-place or laboratory where the whole operation
is carried OIL—Articles which demand consideration in the lamp.—
Continual current and maintemancc of ﬂame.——How effected.—
Considcrations with regard to the action of a candle—In what
respect it ditl'eis from the action of a lamp—Smoke of candles
and lamps, how produced—Lamps with large wicks—with small
wicks.——Reason why the wick ot' tallow candles should not be too
thin.~—VVhy tallow candles require continual snuﬁing and wax
candles snuff themselves—further observations on this subject.

Method of Ascertaining the Illmninating Pow-
er of Candles, Lamps, Gas-Lights, and other
Luminous Bodies. 20

Optical principle assumed as law for determining the relative strength

' of lights of different kinds.—Admeasurement of the intensity of
light—Quantity 0t wax, tallow, oil, &c. requisite for producing a
light of a certain strength.—I\Iethod of increasing the light of tal-
low candles, and to obviate the necessity of strutting them.—A
tallow candle placed in an inclined position 9;in more light than
when placed perpendicularly and studied with an instrument.—
Explanation of the fact—Further observations on this subject.—
Experiments of Mr. \Valker.—~Appear to prove that where com-
bustion is complete, the quantity of light produced by tallow
candles, is in the complicate ratio of their time of burning and
weight of tallow consumed—His method for investigating rules
of this kind.

JlIethods of Increasing the Light of Tallow
Candles, and to 0hviate the lVecessity of
Snaﬁi’ng them. 30

Alteration recommended to be made in the method of burning tal-
low candles, so as to render them to become substitutes for candles
made of wax—1n what it consists—Theory of it.—Advantages
which may be derived from candles which require no snutling and
afl'ord no smoke—Nature ot' tallow candles best adapted for the
purpose. Other inconveniences which attend the use of tallow
czmdles employed in the ordinary \vay.—'l‘abular view. exhibiting
the real and comparative expcncc of burning tallow candles of
ditl‘erent sorts and sizes—Observations of Dr. Franklin and Mr.
“'arrcn, on the ﬂame ot‘candles.—«.\ aturc of the so called Liverpool
lamp.

 

COPITENTS. xiii

\

PART II.

 

GAS-LIG HT.

_ . ' Page
Prehmmm'y Observations. 43

New art of procuring Artiﬁcial Light—nature of it.—Encouragement
given by the Legislature to the new system of procuring light.—
Gas-light company, incorporated by charter, to apply the new art
of illumination by way of experiment, on a large scale, to illumi-
nate the streets and houses of the metropolis.—Powcr and autho-
rities granted to this corporate body.~—are very restricted, and do
not prevent other individuals from entering into competition with
them.—The Company Is bound to furnish a stronger and better light
to such streets and parishes as chusc to he lighted with gas—and at
a cheaper rate than shall be paid for lighting the said places with
0il.—is not permitted to traﬂic in Gas—light machinery—Bounda.
lies of tieir experiments—limit of capital employed.——P0wer oi ,
His Majesty with regard to the Gas—light charter.

Natural History and Chemical Constitutioan
Coal; with Remarks on the Economy of this
kind of Fuel. 45

Natural History of pit—coal.—Immediate constituent parts of coal.—
are a carbonaceous base, combined with more or less earthy or sa-
line matters—relative quantities—are different in diﬂ'erent kinds
of coal.—general division of coal.——Characters of the ﬁrst class of
coal.—athey abound in bitumen—take ﬁre readily—blaze from be—
ginning to end—do not cake together on the ﬁre—require no stir-
ring.——give no Cinders nor slags.——aﬂ'ord light white ashes—Va-
rieties of this class ot' coals met with in the London market—Sc-
cond class—become soft when laid on the ﬁre.——cake together.-
putt up.—throw out tubercular scoriae with jets of ﬂame. require
the poker to prevent the ﬁre from going out—aﬂord scoriae, or
cinders.—-the colour of the ﬂame of this class of coal is not so
white and brilliant as the ﬂame of the ﬁrst class—produce excellent
coke or (ﬁnders—they possess a greater speciﬁc gravity than the
ﬁrst class—they produce, when mixed with the beﬁn‘e-mentioncd
class of coals, the most economical t'ueL—Varieties of this class of
coal met with in the London market—Third class of coals. are
those which are almost destitute of bitumen—are chieﬂy com~
posed of carbon and earthy matters.—-burn with little or no snIokP,
-——give almost no ﬂame. burn like charcoal.—do not cake.—al‘.'nl'd
no tar by distillation, or at least but a small portion—Cannot be
Used in the Gaslight manufacture—afford excellent coke.—Varie.

 

 

.L
s.

 

\

xiv ' CONTENTS.
0

ties of this class of coal.——Hypothesis concerning the origin of coal.
-——The most rational is, that they originate't'rom vegetables—Total
consumption of coals from the rivers Tyne and VVeare, as known
from the registers—Remarks with regard to economy ol'fuel. quan-
tity of heat produced from a given quantity of coal.—what it chieﬂy
lepends upon—great waste of fuel.—how to be obviated.——Best
form of ﬁre—grates calculated for domestic purpOScs.—Further ob-
servations on the economy of fuel.—size of coal.——remarks on it.—
great waste of small coals in open ﬁre grates—Proofs of this state-
ment—the loss in the use of small coal is most considerable to the
poor.——reasons why.—General remarks on the purchasing of coals
by measure.—T he act of Parliament does not take notiee of the
small measures of eoal-sheds.—If it be ever so bad, the public has
no redress—Scandalous abuses practised in the coal trade.—Pro-
posal to do away the present erroneous mode of selling coal by
measure—and to prevent the abuses to which the public is liable.
——so as to do justice to the revenue, to the consumer of coals, to
the coal merchant, as well as to the proprietors of collieries.

‘Thcory of the Combustion of Coal, in Elucida-
tion of the Nature and Production of Gas-
light. Page 68

Phenomena which happen during the combustion of pit—coal.———Ana—
lysis of coal by distillation.—-Great waste of matter capable of
producing light and heat, in the usual mode of burning coal.—
Proofs of this statement—Theory of the production of gas—light,
compared with the production of light obtained by candles and
lamps-place which the discovery of lighting with gas occupies in
the philosophical order of knowledge—leading principle of this art.
—which is justiﬁable by the universal mode in which all light is
produced. ‘

Sketch oflhe Rise and Progress of the Appli .
cation of Coal—gas as a Substitute for pro-
curing Artiﬁcial Light. 73

The discovery of the inﬂammable nature and application of coal-gas
for the production of artiticial light, cannot be claimed by any
body now litiiig.——Eat‘ly notices of theinﬂammable property of the
gas obtained by distilling coal.—Attempts to substitute it for tallow
and oil—Experiments made with coal—gas by Dr. CLAYTON, Dr.
HALES, and the Bishop of LlandatiL—l’irst successful attempt of
lighting manufactories with gas—Creditor and debtor account con-
cerning the expense of this mode of illumination. when compared
with the light obtained by tallow candles—Claims of Mr. MUR-
DOCH with regard to the economical application of coal-gas.—
Claims of Mr. Wimom—Experiments of Mrs NORTHERN, Mr.
CLEGG, Mr. COOK, Mr. ACKERMAhN.—l“.con()mical statements of
the Gas-light illumination when compared with the cost of the
same quantity of light obtained by means of candles and lamps.

 

CONTENTS. xv

Description Qf the Apparatus and Machinery
now successﬂtlly employed for illuminating
Streets, Ifouses, and Illanafactories with Car-
lmretted Hydrogen or Coal~gas. Page 93

Portable (‘hamber Apparatus, very convenient for exhibiting in the
small way, the general nature of the new art of illumination.—and
to ascertain also the comparative value of different kinds of coal
intended to be employed for the production of this species of light.
——construction of the summary parts of the apparatus, and theory
of its action.—Deseription of the Gas-light Apparatus employed for
lighting up Factories, Streets, or small districts—Description of
the retort furnace—of the tar cistern—lime machine—«gasomc—
ten—safety valve, &2e. action of the ditl‘ercnt parts of the appa-
ratus.-—Deseription of a Gas-light apparatus, calculated for lighting
towns or large districts of streets and houses—Action of its sum-
mary parts—Elegant contrivance invented by Mr. Clegg for regu~
lating the pressure of the gasometer.

 

Directions to W orhmen attending the Gas-light
Apparatus; and description of the various-
kinds of gas pipes employed as Illains for
conveying gas, and methods of connecting
them. 117

Philosophy of the Production of Coal-gas.——Its
chemical constitution, general habitades, and
practical remarks concerning the best methods
of obtaining it. 125

Philosophy of the production of coal—gas—Characters of the various
products which the gas-light process aﬂ‘ords, their quantities, and
modes of obtaining them.—Quantity of gas obtainable from a given
weight of coa-l.-—Illurninating power of a given bulk of coal- gas
compared with the illuminating power of a given weight of tallow
candles—Practical directions with regard to the production of the
gas from coal.—Its chemical constitution and analysis—Illuminat-
ing power ofcoal-gas.—~how ascertained and compared with the illu-
minating power of other bodies—quantity of gas obtainable from a
given quantity of coal.—Pit—coal is not the only substance which
aﬁords carburetted hydrogen gas—This gas exists ready formed
in nature.——Mode of collecting it when found native—ls given
out by all kinds of vegetable matter, submitted to distillation in
close vessels—Other sources of obtaining this gazeous ﬂuid.—
Practical directions with regard to the method of obtaining from
coal this gazeous substance, as best suited for illumination——
Chemical constitution of coal-gas.——how ascertained.

xvi . . CONTENTS.

P A RT 111.

 

Utility qf'the Gas-light illmicination with re-
gard to public and private economy. Page 137

Objects to which the new system of lighting with gas may be beneﬁ-
cially applied—Capital advantages of the gas—light illumination.—
there is nothing to spill.-—is well calculated for light-houses, 8w.—
Places and public ediﬁces lighted with coal—gas in this metropolis.
-——Situations best suited for the application of gas-lights.—Places
Where it cannot be used to advautage.——Illumination of barracks,
arsenals, dock yards. 8m. with coal—gas.—Furtber observations on
this subject. Great heat produced by gas-lights.—Reason why the
ﬂame of coal—gas produces more heat than the ﬂame of candles and
lamps—Admeasurcnicnt ot' the comparative degrees of heat pro-

\ duced by gas-lights, oil lamps, tallow and wax candles, Sac—Gas-
lamps and burners, various kinds of.—Ornamcntal chandeliers and
candelabras, for applying coal—gas as a substitute for oil.———Rod
Lamps—Pendent gas-lanips.—Swing branch lamps.—Cockspur
Lamps.—-&c. SLc.

Otker Products obtainable ﬂ'om Coal; namely,
Coke, Tar, Essential Oil, tj‘c. 157

Coke.-—~Its nature—Combustion of it.—Produces a more strong
and lasting heat than coal.—-Explanation of this fact—Advantages
resulting from the use of coke as fueL—Disadvantages of its ap-
plication in certain circumstances—Relalive ell'ect of heat pro-
duced by equal quantities of coke and charcoal.—Method of
measuring the comparative effect of ditl'crent kinds of fuel in pro—
ducing heat.——(‘apital advantages resulting from the application
of coke, as fuel, in the art of burning linic.~—Plaster ot' Pan's,
bricks, &c.———Quantity of coke obtainable from a certain quantity
of pit-coal.—Kind of coke best suited for metallurgical operations.
--—Mode of obtaining it in the Gas-light process.—Sort of coke best
adapted for kitchen and parlour ﬁres.——1\Ianuthcture of it.—Co.-u.
TAIL—How obtained.——Its properties—Earl of Dundonald’s me-
thod of manufacturing tar from coal.—-—Quantity of coal—tar pro-
duced in the Gas-light process from a given quantity of coal.—
Characters of coal-tar obtained from Newcastle coal, diﬂ'er from
that produced from canel COQJ.——COAL PH‘CH.———Process for ob-
taining it.——Properties of eoal-piteh.——Use of it in the arts—Quan—
tity of coal—pitch obtainable from a given quantity of tan—AM—
MONIACAL LIQL'nR produced during the distillation of coal—Its
chemical constitution.—Quantity obtained from a given quantity
of coal.——General observation respecting the scheme of applying
coal-gas as a substitute for candles and lamps.——Etl'ects which it
must produce upon the arts and upon domestic economy—Its
views—Primary advantages—Resources which it presents to in-
dustry and public ceouomy.—lnwhat respect it is entitled to pub-
lic approbation and national encouragement.—Ellects of prejudice

CONTENTS. xvii

against the introduction of new and useful discoveries—Have
operated strongly in retarding the Gas-light illumination .—Remark-
able slowness with which improvements of extended utility make
their way into common use, contrasted with the rapid adoption of
fashionable clianges.—-Other causes unfavourable to the adoption
of new and useful plans—14‘ urther observations on this subject.—
Thc new system of lighting with coal—gas can never supersede the
use ot'candles and moveable lights.——Gas—light illumination cannot
prove injurious to the Greenland ﬁshery—nor can it diminish the
coal—trade—must prove beneﬁcial to it.—The price of coal even
when it is the highest cannot materially affect the beneﬁcial appli-
cation of Gas-lights.—Striking advantages to be derived from the
introduction of gas—lights into manufactories.———Principal expense
which must always attend the gas-light illumination, is the dead
capital employed for erecting the machinery.——Floating capital is
small.—-Advice to private individuals with regard to the erection
of a gas—light apparatus calculated for their own use—Expense
which must attend the application of the new system of lighting
under different circumstances—Entire new scheme of illuminating
streets, or small towns with gas—lights; which would save all the
main pipes for conveying the gas through the streets as well as
the branch pipes which conduct the gas to the lamps—Manage-
ment of the gas—light machinery is extremely simple and easy.~—
The apparatus not liable to be out of order.-——Observations on the
safety of the gas-light illumination.—Misapprehension concerning it.
Causes that have alarmed the public concerning the application
of the new lights.—Gas-lights cannot give rise to those accidents
which have so often arisen from the careless snuﬂing of candles,
Sic—Produce no embers or sparks—Cannot fall, or be disturbed
without becoming extinguished.——~Are the safest of all lights.—
Impossibility of streets or towns lighted with gas to be thrown
suddenly into darkness by the fracture of the gas-pipes conveying
the gas to the lamps—or by the destruction of one or more of the
gas—light machineries employed for preparing the gas—Illustration

. showing the absurdity of such mistaken notions—Curious self-
extinguishing lamp, invented by Mr. Clegg.——His machine which
measures and registers in the absence of the observer, the quan-
tity of gas delivered by a pipe communicating with a gas-light
main.———Leading characters of the new lights—Objects and views
which this art embraces—It. must lessen the consumption of oil.
——-Occasion a defalcation in the revenue.

TABULAR VIEW, exhibiting the quantity of Gas, Coke, Tar,
Pitch, Essential Oil, and Ammoniacal Liquor, obtainable froma
given quantity of Coal; together with an estimate of the quantity
of Coal necessary to produce a quantity of Gas, capable of yield—
ing a light equal in duration of time and intensity to that produced
by tallow candles of diﬂ‘erent kinds.

ESTIMATE of the Price of a Gas-light Apparatus. 193

LONDON Price List of the most essential articles employed in
the erection of aGas-light Apparatus. 194

DIRECTIONS TO THE BOOK BINDER.

Plate l. facing the Title-page; Plate ll, facing page 95; Plate Ill,
facing page 151 ; Plate IV. faring page )54; Plate V, facing page 155;
Plates V1 and VII, at the end of the Book.

A

P RACTI CAL TREATISE

0N

GAS-LIGHT.

 

 

INTRODUCTORY OBSERVATIONS.

INFLUENCE

OF

THE PROGRESS OF THE ARTS

UPON THE

MORALS AND CONDITION OF MAN.

 

IT is an undoubted truth, that the successive
improvements in the condition of man, from a
state of ignorance and barbarism, to that of
the highest cultivation and reﬁnement, are usu-
ally effected by the aid of machinery and expe-
dients, calculated to procure the necessaries,
the comforts, and {elegancies of life; and that
the pre—eminence of any people in civilization is,
and ought ever to be, estimated by the propor-
tional state of industry, and useful labour exist-
ing among them.
B

Z A 'I‘REATISE ON GAS-LIGHT.

In proof of this great and striking truth, no
other argument requires to be offered, than an
immediate reference to the experience of all
ages and places; the various nations of the
earth, the provinces of each nation, the towns,
and even the villages of the same province,
differ from each other in» their accommodations;
and are in every respect more ﬂourishing, the
greater their activity in establishing new chan-
nels of useful employ, calculated to procure
the necessaries and comforts of life. Hence
the nations which have shewn the most inge-
nuity in this way, are not only the richest, but
also the most populous and the best defended:
the provinces of those nations, are seen to
ﬂourish likewise in proportion to their respec-
tive degrees of activity in this respect. And
from these exertions it is, as SMITH“~ empha—
tically remarks, that “the accommodation of
“the European prince does not always so
“ much exceed that of an industrious and fru-
“ gal peasant, as the accommodation of the
“ latter excecds’that of many an African king,
“ the absolute master of the lives and liberties
“ of ten thousand naked savages.”

It was a strange notion of Rousseau to main-
tain that mankind were happier when they
resembled wild beasts, than with all the ex-

” Wealth of Nations, CHAP. 1.

A TREATISE ON GAS-LIGHT. 3

panded knowledge of civilized life; and that
the cultivation of their understanding had tend-
ed to degenerate their Virtues. There can be
no virtue but what is founded on a compre-
hensive estimate of the effects of human ac-
tions, and an animal under the guidance of
instinct can form no such estimate.

The variety of production, of wants, and
fabrication has given rise to barter or ex-
change; mutual supply has increased the sub-
division of labour, and improved the means of
conveyance. Streams, roads, ships, and carri-
ages have extended their beneﬁcial intercourse;
conﬁdence between man and man has advanced
the moral principles of society, and afford-
ed a progression, of which the past gradation
may indeed be traced, but to the future part
of which the imagination can scarcely form
a probable outline. And as the moral and
physical powers of man expand, new resources
present themselves and new agencies are made
subservient to our command, which in an earlier
state of society, would have appeared alto-
gether visionary.

Who among the ancients would have listened
to the extraordinary scheme of writing books
with such rapidity, that one man, by this new
art, should perform the work of twenty thou~

4 A TREATISE 0N GAS-LIGHT.

sand amanuenses? What philosopher would
have given credit to the daring project of navi-
gating the widest ocean ?—or imagined the as-
tonishing effect of gunpowder—or the extended
application of the steam engine? What mortal
would have dared to dive at the bottom of the
sea—or soar aloft into the air—or bid deﬁance
to the thunder of the clouds P Discoveries which
have changed, as it were, the course of human
aﬂ”airs, and the effects of which have already.
carried the intellectual operations of the human
mind, to a height they could by no other means
have attained. The men of those early ages, in
the conﬁdence of their own wisdom, might have
delided these discoveries as impossible, or re-
jected them as visionary; but to those, who enjoy
the full effects of such, and numerous other suc-
cessful inventions, it becomes a duty to reason
upon different principles, and to exert all means
in their power to give effect to the progress of
useful knowledge.

The artiﬁcial production and supply of light
during the absence of the sun, unquestionably
holds a distinguished rank among the most im-
portant arts of life.

If we could for a moment suppose the priva-
tion of artiﬁcial light, it would follow as an imme—
diate consequence that the greatest part of the

A TREATISE ON GAS-LIGHT. 5

globe on which we dwell, would cease to be the
habitation of man. Whether he could ensnare or
overtake those animals upon Whose unprepared
remains he would then be compelled to feed——
whether he might store the ﬁ'uits of the earth for
his winter supply—what might be the physical- and
moral consequences of a state of such desolation,
may perhaps be conjectured; but no estimate can
show its dreadful magnitude. How much 'do our
comforts, and how greatly does the extent of our
powers, depend upon the production and supply
of artiﬁcial light. The ﬂame of a single candle
animates a family, every one follows his occupa-
tion, and no dread is felt of the darkness of night.
It might be a curious speculation to enquire how
far, and in what respect, the morals of men would
become degraded by the want of this contrivance.
But it is sufﬁcient on the present occasion, that,
previous to entering upon a dissertation respecting
a new art of illumination, a train of ideas has
slightly been hinted at, which cannot fail to show
its magnitude and importance. The methods of
procuring and distributing light, during the absence
of the sun, have not hitherto attained the extent of
their possible perfection: there is yet a wide ﬁeld
for improvement in the construction of the instru-
ments of illuminations, and the subject is highly
deserving the attention of every individual.

I!

6 A TREATISE 0N GAS-LIGHT.

The scheme of lighting houses, streets, and
manufactories, by means of the inﬂammable gas,
obtainable by distillation from common pit-coal,
professes to increase the wealth of the nation, by
adding to the number of its internal resources, and
on this ground it is entitled, at least, to a candid
examination.

The apparent slight that has been thrown upon
this new branch of civil economy by some indivi-
duals, who appear to be incapable of judging of
its nature, has contributed to deter sensible and
well disposed persons from wishing it success. It
is the more necessary to state this fact, because,
when a mistaken notion once becomes diffused,
concerning the nature of a new project, persons
of the best intention are liable to become affected
with wrong impressions on their mind. I am
neither a share holder, nor a governor, nor am I
directly or indirectly concerned in any gas-light
association.

The object of the succeeding pages, simply is
to rescue the art of illumination with coal-gas from
misconception and misrepresentation; and by a
fair, and not overcharged statement of its merits
and its disadvantages, to appeal from prejudice
and ignorance, to the good sense of the commu-

nity.

A TREA'I‘ISE 0N GAS-LIGHT. 7

PART I.

THEORY OF THE PRODUCTION

OF

ARTIFICIAL LIGHT.

THE ﬂame of burning bodies consist of such in-
ﬂammable matter in the act of combustion as is
capable of forming a substance called hydrogen
gas or inﬂammable air, more or less pure. When
all circumstances are favourable to the complete
combustion of this gazeous ﬂuid, the ﬂame is per~
fect; if this be not the case, part of the com-
bustible body, capable of furnishing the inﬂam-
mable gas, passes through the luminous ﬂame,
unburnt, and exhibits the appearance of smoke.
Soot therefore always indicates an imperfect com-
bustion. Thus originates the ﬂame of wood and
coal, when they are burned in their crude state.
They contain the elements of a quantity of matter,
which is capable of producing an inﬂammable gas

8 A ‘I‘REA’I‘ISE 0N GAS-LIGHT.

by the application of heat, and subsequent new
chemical arrangement of their constituent parts.

As the artiﬁcial light of lamps and candles ls
afforded by the ﬂame they exhibit, it seems a
matter of considerable importance to society, to
ascertain how the most luminous ﬂame may be
produced With the least consumption of combus—
tible matter. There does not appear to be any
danger of error in concluding, that the light
emitted will be greatest when the matter is com-
pletely consumed in the shortest time. It is there-
fore necessary, that the stream of volatilized
combustible gazeous matter should pass into the
atmosphere with a certain determinate velocity.
If the quantity of this stream should not be duly
proportioned ; that is to say, if it be too large, its
internal parts will not be completely burned for
want of contact with the air. If its temperature
be below that of ignition, it will not, in many
cases, burn when it comes into the open air. And
there is a certain velocity at which the quantity of
atmospherical air which comes in contact with the
vapour or inﬂammable gas will be neither too
great nor too small; for too much air will dimin-
ish the temperature of the stream of combustible
matter so much as very considerably to impede
the desired effect, and too little will render the
combustion languid.

A TREATISE ON GAS-LIGHT. 9

'~ We have an example of a ﬂame too large in the
mouths of the chimneys of furnaces, where the
luminous part is merely superﬁcial, or of the thick-
ness of about an inch or two, according to circum-
stances, and the internal part, though hot, will not
set ﬁre to paper passed into it through an iron
tube; the same defect Of air preventing the com-
bustion of the paper, as prevented the interior
ﬂuid itself from burning. And in the lamp of
Argand we see the advantage of an internal cur;
rent of air, which renders the combustion perfect
by the application of air on both sides of a thin
ﬂame. So likewise a small ﬂame is always whiter
and more luminous than a larger; and a short
snuff of a candle giving out less combustible mat-
ter in proportion to the circumambient air; the
quantity of light becomes increased to eight or
ten times what a long snuff would have afforded.
The light of bodies burning With ﬂame, exists
previously either combined with the combustible
body, or with the substance which supports the
combustion. We know that light exists insome
bodies as a constituent part, since it is disengaged

from them when they enter into new combina-
tions, but we are unable to obtain in a separate

state the basis with which it was combined.
That in many cases the light evolved by arti-
ﬁcial means is derived from the combustible
c .

ti

10 "A TREATISE 0N GAs-LIGHT.

body, is obvious, if we recollect that the colour
of the light emitted during the process of com-
bustion varies, and that this variation usually
depends not upon the medium which supports
the process of combustion, but upon the com-
bustible body itself. Hence the colour of the
ﬂame of certain combustibles, even of the purest
kind may be tinged by the admixture of various
substances.

The ﬂame of a common candle is far from be-
ing of an uniform colour. The lowest part is
always blue; and when the ﬂame is sufﬁciently
elongated, so as to be just ready to smoke, the
tip is red or brown.

As for the colours of ﬂame that arise from
coals, wood, and other usual combustibles, their
variety, which hardly amounts to a few shades of
red or purple, intermixed with the bright yellow
light, seems principally to arise from the greater
or less admixture of aqueous 'vapour, dense
smoke, or, in short, of other incombustible pro-
ducts which pass through the luminous ﬂame
unburnt.

Spirit of wine burns with a blueish ﬂame.
The ﬂame of sulphur has nearly the same tinge.
The ﬂame of zinc is of a bright greenish white.
The ﬂame of most of the preparations of copper,
or of the substances with which they are mixed,

A TREATISE 0N GAS-LIGHT. [l

is vivid green. Spirit of wine, mixedrwith com
mon salt, when set on ﬁre, burns with a very un:
pleasant effect, as may be experienced by looking
at the spectators who are illuminated by such
light. If a spoonful of spirit of Wine and a
little boracic acid, or nitrate of copper be stirred
together in a cup, and then be set on ﬁre, the
ﬂame will be beautifully green. If spirit of
wine be mixed with nitrate of strontia, it will,
afterwards, on being inﬂamed, burn with a car-
mine red colour. Muriate of lime tinges the
ﬂame of burning spirit of wine of an orange
colour.*

* See Chemical Amusement, comprising minute instructions for
performing a series of striking and interesting chemical experi-
ments, p. 8, 8w. '

(12)

THEORY

THE ACTION OF

CANDLES AND LAMPS.

 

 

BEFORE we consider the general nature of
Gas-light, it will be necessary to give a short
sketch of the theory and action of the instru-
ments of illumination employed for supplying
light, together with some other facts connected
with the artiﬁcial production and distribution of
light; such a proceeding will enable us to un-
derstand the general nature of the new system
of illumination which it is the object of this
Essay to explain.

To procure light for the ordinary purposes
of life, we are acquainted with no other ready
means than the process of combustion.

The rude method of illumination consists, as
is sufﬁciently known, in successively burning
certain masses of fuel in the solid state: com-

A TREATISE ON GAS-LIGHT. 13

. mon ﬁres answer this purpose in the apartments
of houses, and in some light-houses. Small, ﬁres
of resinous wood, and the bituminous fossil,
called canel-coal, are in some countries applied
to the same end, but the most general and useful
contrivance is that which fat, or oil, of an animal
or vegetable kind is burned by means of a wick,
and these contrivances comprehend candles and
lamps. .

In the lamp, the combustible substance must
be one of those which retain their ﬂuidity at the
ordinary temperature of the atmosphere. The,
candle is formed of a material which is not fusi—
ble but at a temperature considerably elevated.

All these substances must be rendered volatile
before they can produce a ﬂame; but for this
purpose it is sufﬁcient to volatilize a small quan-
tity of any of them, successively; for this small
quantity will sufﬁce to give a useful light; and
hence we must admire the simple, yet wonderful
contrivance of a common candle or lamp. These
bodies contain a considerable quantity of the
combustible substance, suﬂicient to last several
hours; they have likewise, in a particular place,
a slender piece of spongy vegetable substance,
called the wick, which in fact is the ﬁre-place, or
laboratory where the whole operation is con-
ducted.

14 A TREATISE AON GAS-LIGHT.

There are three articles which demand our at-
tention in the lamp-the oil, the Wick, and the
supply of air. It is required that the oil should
be readily inﬂammable; the oﬂice of the wick
appears to be chieﬂy, if not solely, to convey the
oil by capillary attraction to the place of combus-
tion; as the oil is decomposed into carburetted
hydrogen (gas and other products, other oil suc-
ceeds, and in this way a continual current and
maintenance ‘of ﬂame is' effected.

When a candle is for the ﬁrst time lighted, a
degree of heat is given to the Wick, suﬂicient ﬁrst
to melt, and next to decompose the tallow sur-
rounding its lower surface; and just in this part
the newly generated gas and vapour is, by admix-
ture with the air, converted into a blue \ﬂame;
which, almost instantaneously encompassing the
whole body of the vapour, communicates so much
heat to it, as to make it emit a yellowish white
light. The tallow now liqueﬁed, as fast as it boils
away at the top of the wick, is, by the capillary
attraction of the same wick, drawn up to supply
the place of what is consumed by the cotton.
The congeries of capillary tubes, which form the
wick, is black, because it is converted into coal;
a circumstance common to it with all other vege
table and animal substances, when part of the
carbon and hydrogen which enter into their com-

A TREATISE ON GAS-LIGHT. 15

position having been acted on by combustion, the
remainder and other ﬁxed parts are by (any means
whatever coVered and defended from the action
of v the air. In this case, the burning substance
owes its protection to the surrounding ﬂame.
For when the wick, by the continual wasting of
the tallow, becomes too long to support itself in
a perpendicular situation, the top of it projects
out of the cone formed by the ﬂame, and thus
being exposed to the action of the air is ignited,
loses its blackness, and is converted into ashes;
but that part of the combustible which is succes-
sively rendered volatile by the heat of the ﬂame is
not all burnt, but part of it escapes in the form of
smoke through the middle of the ﬂame, because
that part cannot come in contact with the oxygen
of the surrounding atmosphere; hence it follows,
that with a large wick and a large ﬂame, this -
waste of combustible matter is proportionately
much greater than with a small wick and a small
ﬂame. In fact, when the wick is not greater than
a single thread or cotton, the ﬂame, though very
small, is, peculiarly bright, and free from smoke;
whereas in lamps, with very large Wicks, such as
are often suspended before butchers’ shops, or
with those of the lamp-lighters, the smoke‘is very
offensive, and in great measure eclipses the light
of the ﬂame.

16 ' A TREATISE 0N GAS-LIGHT.

. 'A candle differs from a lamp in one very essen-
tial ,circumstance; viz. that the oil or tallow is
liquﬁed, only as it comes into the vicinity of the
combustion; and this ﬂuid is retained in the ho]
low of the part, which is still concrete, and forms
a kind of cup. The wick, therefore, should not
on this account, be too thin, because if this were
the case, it would not carry oﬂ‘ the material as
fast as it becomes fused; and the consequence
would be, that it would gutter or run down the
sides of the candle: and as this inconvenience
arises from the fusibility of the tallow it is plain
that a more fusible candle will require a larger
wick; or that the wick of a wax candle may be
made thinner than that of one of tallow. The
ﬂame of a tallow candle will of course be yellow,
smoky, and obscure, except for a short time after
snuﬂing. When a candle with a thick wick is
ﬁrst lighted, and the wick snuffed short, the ﬂame
is perfect and luminous, unless its diameter be
very great; in which case, there is an opake part
in the middle, where the combustion is impeded
for want of air. As the wick becomes longer,
the interval between its upper extremity and the
apex of the ﬂame is diminished; and consequently
the tallow which issues from that extremity, hav-
ing a less space of ignition to pass through, is less
completely burned, and passes off partly in smoke.‘

A TREATISE ON GAS-LIGHT. 17

This evil increases, until at length the upper ex-
tremity of the wick projects beyond the ﬂame
and forms a support for. an accumulation of soot.
which is afforded by the imperfect combustion,
and which retains its ﬁgure, until, by the descent
of the ﬂame, the external air can have access to
the upper extremity; but in i this case, the requi‘
site combustion, which might snuff it, is not
effected; for the portion of tallow emitted by
the long wick is not only too large to be per-
fectly burned, but also carries off much of the
heat of the ﬂame, while it assumes the elastic
state. By this diminished combustion, and in-
creased aﬂlux of half decomposed oil,‘a portion
of coal or sootis deposited on the upper part
of the wick, which gradually accumulates, and
at, length assumes the appearance of a fungus.
The candle then does not give more than one—
tenth of the light which the due combustion of
its materials would produce; and, on this ac-
count, tallow candles require continual snuﬂing-
But if we direct our attention to a wax candle,
we ﬁnd that as its wick lengthens, the light in-
deed becomes less. The wick, however, being
thin and ﬂexible, does not long occupy its place
in the centre of the ﬂame; neither does it, even
in that situation, enlarge the diameter of the ﬂame,
so as to prevent the access of air to its internal
D

18 A TREATISE ON GASeLIGHT.

part. When its length is too great fer the verti-
cal position, it bends on one side; and its extre-
mity, coming in contact with air, is burned to
ashes; except such a portion as is defended by
the continual afﬂux of melted wax, which is vola-
tilized, and completely burned, by the surround-
ing ﬂame. Hence it appears, that the difﬁcult
fusibility of wax renders it practicable to burn a
large quantity of ﬂuid by means of a small wick,
and that this small wick, by turning on one side
in consequence of its ﬂexibility, performs the ope-
ration of snuﬂing itself, in a much more accurate
manner than can ever be performed mechani
cally. From the above statement it appears, that
the important object to society of rendering tallow
candles equal to those of wax, does not at all
depend on the combustibility of the respective
materials, but upon a mechanical advantage in the
cup, which is afforded by the inferior degree of
fusibility in the wax: and that, in order to obtain
this valuable object, one of the following effects
must be produced: either the tallow must be
burned in a lamp, to avoid the gradual progres-
sion of the ﬂame along the wick; or some means
must be devised to enable the candle to snuff
itself, as the‘ wax-candle does ; or the tallow itself
must be rendered less fusible by some chemical
process. The object is, in a commercial point of

A TREATISE on GAS-LIGHT. ‘ 19

view, entitled to assiduous and extensive investi-
gation. Chemists in general suppose the hard-
ness or less fusibility of wax to arise from oxygen.
Mr. NICHOLSON’X‘ is led by various considerations
to imagine, that the spontaneous snuﬂing of can—
dles made of tallow or other fusible materials,
will scarcely be effected but by the discovery of
some\material for the wick, which shall be volu-
minous enough to absorb the tallow, and at the
same time sufﬁciently ﬂexible to bend on one
side.

’ Philosophical Journal, 4to Series, Vol. 1. p. 70.:

(20)

METHOD

OF

ASCERTAINING THE ILLUMINATING POWER

OF

CANDLES, LAMPS, GAS - LIGHTS,

AND OTHE R

LUMINOUS BODIES.

._~_._
.———

THOUGH the eye is not ﬁtted to judge of the
proportional force of different lights, it can dis-
tinguish, in many cases with great precision, when
two similar surfaces, presented together, are
equally illuminated. But as the lucid particles
are darted in right lines, they must spread uni-
formly, and hence their density will diminish in
the duplicate ratio of their distance. From the
respective situations, therefore, of the centres of
divergency, when the contrasted surfaces become
equally bright, we may easily compute their re-
lative degrees of intensity.

For this purpose it is assumed as a principle,
that the same quantity of light, diverging in all

A TREATIBE on GAB-LIGHT. 21

directions from a luminous body, remains undi-
minished in all distances from the centre of diver~
gency. Thus we must suppose, that the quantity
of light falling on every body, is the same as
would have fallen on the places occupied by the
shadow; and if there were any doubt of the truth
of the supposition, it might be conﬁrmed by some
simple experiment. _Theref0re, it follows, that,
since the shadow of a square inch of any surfaces
occupies at twice the distance of the surface from
the luminous point the space of four square inches,
the intensity of the light diminishes as the square
of the distance increases. If, consequently, we
remove two sources of light to such distances
from an object that they may illuminate it in
equal degrees, we may conclude that their ori.
ginal intensities are inversely as the squares of
the distances.

Hence, if two lights of unequal illuminating
powers shine upon the same surface at equal ob-
liquities, and an opake body be interposed be-
tween them and the illuminated surface, the two
shadows produced, must differ in blackness or
intensity in the same degree. For the shadow
formed by intercepting the greater light, will be
illuminated by the smaller light only, and re-
versely the other shadow will be illuminated. by
the greater light: that is to say, the stronger

22 A TREATISE 0N GAS-LIGHT.

light will be attended with the deeper shadow.
Now it is/easy, by removing the stronger light
to a greater distance, to render the shadow
which it produces at the common surface equal
to that afforded by the less. Experiments of this
kind may be conveniently made by fastening a
sheet of white paper against the wall of a room;
the two lights, of whatever nature they are, in-
tended to be compared, must then be placed so
that the ray of light from each shall fall with
nearly the same angle of incidence upon the
middle of the paper. In this situation, if a book
or other object be held to intercept part of the
light which would have fallen on the paper, the
two shadows may be made to appear as in this
ﬁgure; 7 i i I

where A represents the surface illuminated by
one of the lights only; B, the surface illuminated
by the other light; C, the perfect shadow from
which both lights are excluded. It will easily be
understood that the lights about D and E, near
the angle F, will fall with equal incidences when
the double shadow is made to occupy__the mid-

A TREATISE ON GAS-LIGHT. ‘23

dle of the paper; and consequently, if one or
both of the lights he removed directly towards or
from the paper, as the appearances may require,
until the two shadows at E and D have the same
intensity, the quantities of light emitted by each
will be as the squares of the. distances from the
paper. By some experiments made in this way,
the degree of illumination of different lights may
readily -be ascertained to the tenth part of the
whole. And, by experiments of this kind, many
useful particulars may be shewn. For, since the
cost and duration of candles, and the consump-
tion of oil in lamps, are easily ascertainable, it may
be ascertained whether more or less light is ob-
tained at the same expence during a given time,
by burning a number of small ca‘ndles instead of
one or more of greater thickness. It will therefore
be easy to compare the power of different kinds
of lamps, candles, or gas-lights, so as to deter-
mine the relative cost of each particular kind of
the combustible substance employed for furnishing
light :-for example, if a candle and a gas-burner
supplying coaLgas, adjusted by a stop-cock, pro-
duce the same darkness of shadow, at the same
distance from the wall, the strength or intensity of
light is the same. An uniform degree of intensity
of the gas-light may readily be produced, by
opening or shutting the stop-cock, if more or less

24 A ’I‘REATISE ON GAS-LIGHT.

. be required, and the candle is carefully snuffed
to produce the most regular and greatest quantity
of light. The size of the ﬂame in experiments of
this kind of course becomes unnecessary and will
vary very much with the quality of the coal-gas.
The bulk of the gas consumed, and the quantity
of tallow used, by weighing the candle before and
alter the experiment, furnish the data for ascer-
taining the relative costs of tallow and gas-light,
when compared with each other.

From experiments made by Count RUMFORD,
concerning the quantity of materials requisite for
producing a light of a certain intensity for a given
time: it was found that we must burn of wax
100, of tallow 101, of oil, in an Argand’s lamp,
129, of an ill-snuffed tallow candle 229 parts, by
weight. And with regard to the quantity of car-
buretted hydrogen or coal-gas, I have found that
from 18 to 20 cubic feet (according to the purity
of the gas) are required to give a light equal in
duratiOn and in illuminating powers to 11b. of
tallow candles, six to the pound, provided they
were set up and burnt out one after another.

A general statement of the illuminating power
of coal-gas, when compared with‘tallow light will
be given hereafter.

(25>

FURTHER ILLUSTRATIONS
or m mom: or
COMPUTING THE RELATIVE COST 0R VALUE
on

LIGHT,

EJIIT TED B Y

CANDLES, LAMPS, Sc OTHER BODIES.

 

IT is sufﬁciently known that the light of a can-
dle, whiCh is so exceedingly brilliant when ﬁrst
snuffed, is very speedily diminished to one-half,
and is usually not more than one-ﬁfth or one—sixth
before the uneasiness of the eye induces us to
snuff it.* Whence it follows, that if candles could
be made so as not to require snuﬂing, the average
quantity of light afforded by the same quantity of
combustible matter would be more than doubled.

When a lighted candle is so placed as neither
to require snuﬂing or produce smoke, it is reason—

. Ezekiel Walker.—-Nicholson’s Journal, Vol. IV. 8vo. Series.
E

26 A TREATISE 0N GAS'LIGHT.

able to conclude that the whole of the combus»
tible matter which is consumed is converted to.
the purpose of generating light; and that the in-
tensities of light afforded in a given time, by can-
~dles of different dimensions, are in proportion to
the quantity of matter consumed. That is to
say; when Candles are made of the same mate-
rials, if ene candle produce twice as much light
as another, the former will in the same time lose
twice as much weight as the latter.

To prove the truth of this position, Mr. Walker
made the experiments contained in the follow-

mg

 

 

 

 

 

 

 

 

 

TABLE.
No. of Weight of Distance of
a" No. of the Time me Candles Strength of the Candle-
Experi- Candles. of burning. Consumed in Light. ﬂow the
meat. 3 given time. WI"-
h. 111. oz. dr. Feet.
‘ 1 3 0 0 15 l 7
1 3 3 0 l I} 1 + 7
l Mould 3 o 0 15 1 7
y l 2 55 0 15 l 8
2 3 2. 55 l 0 l + 8
l Mould 2 55 0 15 l 8
1 3 0 0 151’; 1 8
3 { 3 3 0 1 2 1i 8}
Mould 3 0 l 0 1 8
f 5 3 o 1 5 1.13 8%
4 l Mould 3 o 1 1t s. s

 

 

 

 

 

 

 

 

 

A TREATISE 0N GAS-LIGHT. 27

These experiments, Mr. walker informs ‘us,
were made in the following manner :—

Three candles, the dimensions of which are
given in the table, against 1, 3‘, and mould, These
were ﬁrst weighed, and then lighted at the same
instant. At the end of the time inserted in the
third column of the above table, they were ex-
tinguished and weighed again, and the loss of
weight of each candle is contained in the fourth
c'olumn.

The three ﬁrst experiments were made under
such favourable circumstance, that there was little
doubt of their results being more accurate than
what practical utility requires, but the fourth ex-
periment cannot be depended on so much, in con-
sequence of the variable light of No. 5. This
candle was moved so often to keep the two sha-
dows equal, that it was found necessary to set
down its mean distance from the wall by estima;
tion; but as this was done before the candles
were weighed, the experimenter’s mind could not
be under the inﬂuence of partiality for a system.

The method which Mr. Walker employed in
comparing one light with another in each experi-
ment, was that which has been described page 22.

1. The experiments were made at different
times, and the light of the mould candle was
made the standard, with which the lights of the

28 A TREATISE 0N GAa-LIGHT.

others were compared; But it must not be under-
stoOd, that this candle gave the same strength of
light in every experiment.

2. The sign + in the ﬁfth column, signiﬁes that
the candle against which it is placed, gave a
stronger light than the others.

From the experiments contained in the table,
it appears to be an established law, where com-
bustion is complete, that the quantities of light
produced by tallow candles, are in the complicate
ratio of their times of buming and weights of
matter consumed.

For if their quantities of matter be equal, and
times of bm‘ning the same, they will giye equal
quantities of light, by the experiments.

And if the times of burning be equal, the
quantities of light will be directly as their weights
of matter expended. .

Therefore the light is universally in the com-
pound ratio of the time of burning and weight of
matter consumed.

It'the law which Mr. \Valker has endeavoured
to prore, both by reason and experiment, be ad-
mitted, we have a standard with which we may
compare the strength of any other light.

Let a small mould candle, when lighted, he so
placed as neither to produce smoke nor require
snuﬂing, and it will lose an ounce of its weight

,.
A TREATISI on eAs-Llenfr. 29

in three hours. Let this quantity of light pro-
duced under these circumstances, be represented
by 1.00.

Then should this candle at any other time, lose
more or less of its weight in three hours than an
ounce; the quantity of light will be still known,
because the quantity of light in a given time is
directly as the weight of’ the candle consumed“.

‘ To investigate rules for this purpose, 1. Let M represent the
mould candle, at its distance from the wall, on which the shadows
were compared, at its quantity of matter consumed in a given time,
(t) and Q the quantity of light emitted by M in the same time: 2. Let
I; represent any other candle, 1: its distance from the same wall, and
y its quantity of matter consumed, in the time t.

Then as the intensities of light are directly as the squares of the
distances of the two candles from the wall, we have as a‘ : Q :61:
b‘ x Q

a?-

 

= the quantity of light, emitted by m in the time.

Then let us suppose that the quantiﬁes of light are directly as the
quantities of matter consumed in the time t, and we have, As x:

Q : : 31:2?— = the quantity of light emitted by m in that time. by

hypothesis.
If x

a7.

YXQ (Theo. 2.) the quantiﬁer

Now, when Q (Theo. 1. is =

 

 

of light of M and m are directly as their quantities of matter cnn
mined in any given time.

(30)

\

METHOD

or INCREASING
‘ THE LIGHT 0F TALLOW CANDLES,

AND 1'0 OBVIATI THE

NECESSITY OF SNUFFIN G THEM.

Mr. EZEKIEL WALKER has shewn that, if a
triﬂing alteration be made in the method of using
common tallovv candles, they will become excel-
lent substitutes for those of wax.

A Common candle, weighing one-tenth of a
pound, containing fourteen single threads of ﬁne
cotton, placed so as to form an angle of 30 de-
grees* with the perpendicular, and lighted, re-
quires no snuﬁing; and what is much more valu-
able for some purposes, it gives a light that is
nearly uniform in strength without the least
smoke. These effects are thus produced : I

" Candlesticks may be made to hold the candle at this angle, or
they may be so contrived as to hold the candle at any angle at plea-
Iure. “ '

A TREATISE 0N GAS-LIGHT. 31

When a candle burns in an inclined position,
most part of the ﬂame rises perpendicularly from
the upper side of the Wick, and when viewed in
a certain direction, it appears in the form of an
obtuse angled triangle. And as the end of the
wick projects beyond the ﬂame at the obtuse an-
gle, it meets with the air, and is completely burnt
to ashes: hence it is rendered incapable of act-
ing as a conductor to carry off part of the com-
bustible matter in the form of smoke. By this
spontaneous mode of snuﬂing, that part of the
wick which is acted upon by the ﬂame continues
of the same length, and the ﬂame itself very
nearly of the same strength and magnitudei“.

The advantages which may be derived from can-
dles that require no snuﬂing and afford no smoke,
may be readily understood; but these candles
have another property which ought not to be
passed over in silence. A candle snuffed by an
instrument gives a very ﬂuctuating light, which,
in viewing near objects is highly injurious to the
eye; and this is an inconvenience which no shade
can remove. But when a candle is snuffed Spen-
taneously, it gives a light so perfectly steady and
,so uniformly bright, that the adjustments of the

’ The mck’s not being unifomly twisted throughout, may occasion
a little variation in the dimensions of the ﬂame.

32 A TREATISE ON GAS-LIGHT.

eye remain at rest, and distinct vision is performed
without pain, and without uneasiness.

Candles, on which Mr. WALKER has made ex-
periments, are described in the following

 

 

T A B L E.
No. Of candles to Length No. of single
No. the pound in threads of ﬁne cotp
avou-duporse inches. ton in the wick.
weight.
1 14 8.5 10
2 l3 9. 12
3 10 9.74 14
4 8 10. 20
I 6 10.25 24

 

 

 

 

 

Mould. f G 13.

 

Number 1, 2, and 3. These candles, when
lighted and placed to form an‘ angle of 30° with
the perpendicular, require no snufﬁng: they give
lights which are nearly equal, and combustion
proceeds so regularly, that no part of the melted
tallow escapes unconsumed, except from ac-
cidental causes.

No. 4, placed at the angle mentioned above,
and lighted, requires no snuﬂing: it gives a
light very little stronger than No. 1, but its colour
is not quite so white, nor its ﬂame so steady. »

A TREATISE ON GAS-LIGHT. 33

No. 5, This candle, placed at an angle of 30°
and lighted, requires no sun-ﬂing; its ﬂame is rather
ﬂuctuating, and not so white as No. _4, nor is its
strength of light much greater than'No.1. The
melted tallow sometimes overﬂows when the air
in the room is put in motion; yet thelight of this
candle is much improved by being placed in an
inclined position.

The mould candle, treated in the same manner,
affords a very pure steady ﬂame, without smoke
and without snuﬂing, and its strength of light is
about equal to that of No. l.

The experiments have not been sufﬁciently
numerous to determine with precision which of
these candles affords the most light at a given
expence, but the few experiments which hay;
been made, seem to indicate, that the“ quantity
of light is nearly as the quantity of combusti-
ble matter consumed, and thus a candle which
is used in the manner pointed out gives more
light than a candle of the same dimension set
perpendicularly and snuffed, because one part
of a candle that is snuffed, is thrown away,
and another part ﬂies off in the form of smoke.
And this is not the only inconvenience that
attends the using candles in this manner, and
which the other method is free from, for the

r

34 A TREATISE 0N GAS-LIGHT.

light which it gives is of a bad quality, on ac-
count of its being variable and undulating.

From the time that a candle is snuffed till it
wants snuﬂing again, its strength of light scarcely~
continues the same for a single minute. And
that variation which frequently takes place in the
height'of the ﬂame, is a matter of still more
serious. consequence.

The ﬂame of a long candle placed vertically
when it is snuﬂ'ed burns steadily, is about two
inches high, but it very frequently rises to the
height of four inches or upwards; drOps down
again in a moment, till it is less than three inches,
and then rises again. In this manner the ﬂame
continues in motion for some time before it re-
turns to its original dimensions. But it does
not continue long in a quiescent state before
it begins a ’new series of undulation. In this
manner the candle burns till the top of the wick
is seen near the apex of the ﬂame, carrying off
clouds of smoke. In this state of things the eye
becomes uneasy for want of light, and the snuf-
fers are applied to remove the inconvenience.

MR. WALKER further observes, that it is these
sudden changes, and not the nature of candle-
light itself, that do so much injury to the eye
of the student and artist; and that injury may

A TREATISE 0N GAS-LIGHT. 35

be easily prevented, by laying aside the snuﬂ'ers,
and in the place of one large candle, let two
small ones be used in the manner stated.

The following observations on this subject
are copied from the Monthly Magazine; 1805.
p. 206.

“ It is scarcely necessary to observe, that the
combustion of candles proceeds the quicker in
proportion as the inclination is greater. From
the experiments which I have made, I should
consider an angle of forty degrees with the per-
pendicular as the maximum of inclination, be-
yond which several considerable inconveniencies
would occur; and I should take 25 degrees
as the minimum of inclination, ‘ less than which,
does not sufﬁciently expose the point of the wick
to the action of the air.

“ By those who are much in the habit of read-
ing or writing by candle-light, it will also be
esteemed no inconsiderable addition to the ad—
vantages already mentioned, that the trouble of
seeking and applying the snuﬂ‘ers is superseded.
A candle of common size in a vertical position,
requires the application of the snuﬂ'ers forty
ﬁve times during its complete consumption.

“But I found an obstacle to the adoption of
MR. WALKER’S plan, which, from the inclined
position of the candle. it did not immediately

\

36 A TREATISE ON GAS-LIGHT.

occur to me by what means to counteract. Any
agitation of the air of the room, occasioned
either by the opening or shutting of a door, or
by the quick passage of a person near the can-
dle, caused the melted tallow to run over, or,
in more familiar ‘language, caused the candle to
gutterrwhich, with the candle in this position
became an insuperable bar to the use of it.
s,» “ For the prevention of this inconvenience, I
have had a wire skeleton-shade adapted to a
rod bearing the same inclination as the candle,
and which at bottom joins the candlestick in
an horizontal line of about two inches, termi—
nating in a nozzle ﬁtting that of the candlestick.
——The distance of this rod from the candlestick,
or, which is the same thing, the length of the
foot or horizontal line, is of course to be deter-
mined by the distance between the two circles
which form the upper and lower apertures of
the shade—It may serve, perhaps, more famili-
arly to describe this part of the apparatus, to state,
that it bears perfect resemblance to two ﬁrst
strokes of the written ﬁgure 4; and third stroke,
if ‘carried up as high as the ﬁrst and made slop-
ing instead of upright, will very well represent
the situation of the candle.

“'When a strong light, for the purposes of
reading or writing, is required, white silk or

A TR’EATISE 0N GAS-LIGHT. 37

paper may be used, as is common, over the skele-
ton; but when it is required that the light should
be dispersed over the room, a glass of a similar
shape may be adopted, for the purpose of pre-
venting the ﬂame from being inﬂuenced by any
agitation of the air of the room. If the upper
circle of the shade be four inches in diameter,
the apex of the ﬂame will be within it during
more than half the time of the complete consump-
tion of the candle; the shade will not, therefore,
require adjusting for the purpose of preventing
injury to the silk, or whatever else may be used
over the skeleton, more than once during that
time.

“ Being myself much averse to the interrup-
tions which a candle used in a vertical position
occasions, and which, though short, may, under
some circumstances, be highly vexatious, I wish
to extend to others a beneﬁt which I prize rather
highly.” '

Lord STANHOPE“ has published a simple me-
thod of manufacturing candles, which, according
to his Lordship’s statement, is superior to the
method usually employed. The principles upon
which the process depends are the following 2—-
First, the wick of the candle is to have only three-

’ Repository of Arts, Vol. I, p. 86.

38 A TREATISE ()N GAS-LIGHT.

fourths of the usual number of cotton threads, if
the candle be of wax or s'permaceti; and only
-two thirds of the usual number, if the candle be
of tallow. Secondly, it is required that the wick
in all cases be perfectly free from moisture, a
circumstance seldom attended to in the manufac-
turing of candles; and thirdly, to deprive the
wick of wax candles, of all the air which is en-
tangled in its ﬁbres, and this, may conveniently
be done, by boiling it in melted wax, till no more
air bubbles, or froth appear on the surface of the
ﬂuid.

If these circumstances be attended to, three
candles of any size thus prepared, last as long as
four of the same size, manufactured in the com-
mon way. The light which they aﬂbrd is superior
and more steady, than the light of common can-
dles; and lastly, candles made in this manner,
whether of wax, spermaceti, 0r tallow, do not
require to be snuffed as often. Besides all this,
they ﬂame much less, and are consequently bet-
ter for writing, reading, working and drawing,
than candles made by the common method.

The following observations will enable any
person who is willing to try the candles manufac-
tured according to Lord Stanhope’s plan, to
ascertain the real value of the improvements sug-
gested by his Lordship. It shews also the result

A TREATISE 0N GAS-LIGHT. 39

of some experiments, made to ascertain the ex-
pence of burning oil in lamps with wicks of va-
rious sizes. » ‘

A taper lamp, with eight threads of cotton, will
consume in one hour 7—3 oz. of spermaceti oil:
at six shillings per gallon, the expence of bum-
ing t“ elve hours is 13.71 farthings. i

At seven shillings, it is 15.995 farthings.

At eight shillings, it is 18.280 farthings.

N. B. This gives as good a light as tallow can-
dles of eight and ten in the pound. This lamp
seldom wants snuﬂing, and casts a steady and
Strong light. .

A taper, chamber, or watch lamp, with four
ordinary threads of cotton in the wick, consumes
1.664 oz. of spermaceti oil in one hour: the oil
at seven shillings per gallon, the expence of bum-
ing twelve hours, 7.02 farthings.

At eight shillings, it is 8.022 farthings,

At nine shillings, it is 9.024 farthings.

40

TABLE,

A TREATISE 0N GAS-LIGHT.

Exhibiting aseries of experiments, made with a
view to determine the real and comparative
. expence of burning "candles of different sorts

and sizes

 

 

 

 

 

 

 

 

l The expeneeln
The time twelve houn'when
Number of Weight of Time one that one Ecandles are at 123.
candles in one auntie. candle lasted pound will dozen, which also
1 'Ihen‘s the proportion
of expence at any
price, per dozen.
Farthings and
oz. hr. min. hr. min. hundredth parts,
Asmall 0 3 15 26 9.70
wick. 0 2 40 34 11.40
Alargc O 2 40 2 13.08
Wick. l. 3 27 24 13.92
1 3 36 24 15.00
2 4 9 12 17.88
2 4 15 0 16.94
2 5 19 15 19.06
Moulds at 14d.
per dozm.
With 7 20 39 15.74.
wax'd 9 3 20 18.56
wick. 17 30 30 16.825
;

 

 

 

The time each candle lasted, was taken from

an average of several trials on each size.
It has been suggested by Dr. FRANKLIN, that

the ﬂame of two candles used, gives a much

stronger light than both of them separately.
The same has been observed by Mr. WARREN,

to be the case with ﬂames of gas-lights, which,

A TREATISE ON GAS-LIGHT. 41

when combined, give a much stronger light than
they would afford, when in a separate state.

Indeed, in; all cases, Where ﬂames for producmg
light are placed near to each other, it is always
beneﬁcial to preserve the heat of the ﬂame as
much as possible. _One of the most simple
methods of doing this, is no doubt, the placing
of the several ﬂames together, and as near as
possible to each other, without touching; in
order that they may mutually cover and defend
each other, against the powerful cooling inﬂuence
of the surrounding cold bodies. This principle
is now employed in the Liverpool lamp, which
acts by several ﬂat or ribband‘wicks placed in the
form of a cylinder. The power of illumination of
this lamp is superior in effect and more economi-
cal than any other lamp in use—and as ﬂame is
perfectly transparent to the light of another ﬂame
which passes through it, there is no danger of
loss of light on account of the ﬂames covering
each other.

ii f‘ﬁ “ 9f?"- éiﬁiggab

{EMQ} mm ”mi-rm

éﬁih 3&5; ' gmd‘;
gﬂiywumnm 32R 73!»

'1 5d,} ﬂ“ Immﬁwm ”mm 3“

 

(‘53)

PA RT 11.

GAS-LIGHT.

 

PRELIMINARY OBSERVATIONS.

A New art of procuring artiﬁcial light, which
consists in burning the gazeOUS ﬂuid obtained by
distillation from common spit-coal, has of late en-
gaged the attention of the public, under the name
of gas-light. /

The encouragement that has been given for
some years past by the legislature to this system
of lighting, has induced certain individuals to
apply the coal-gas light for the illumination of
streets, houses, roads, and public ediﬁces. And
it is sufﬁciently known that a,company has been
incorporated by charter under the name of the
“ Gas Light and Coke Company,” to apply this
new art of procuring light, by Way of experiment,

44 A TREATISE 0N GAS-LIGHT.

on a large scale, in lighting the streets of the me-
tropolis.*

The power and authorities granted to this cor-
porate body are very restricted and moderate.
The individuals composing it have no exclusive
privilege; their charter does not prevent other
persOns from entering into competition with them.
Their operations are conﬁned to the metropolis
where they are bound to furnish not only a stron-
ger and better light to such streets and parishes
as chuse to be lighted with gas, but also at a
cheaper price than shall be paid for lighting the
said streets with oil in the usual manner. The
corporation is not permitted to trafﬁcin machinery
for manufacturing or conveying the gas into pri-
vate houses, their capital or joint stock is limited
to 200,000]. and His Majesty has the power of
declaring the gas-light charter void, if the com-
pany fail to fulfil the terms of it.

’ An Act for gmnting certain powers and authorities to a company
to be incorporated by charter, called the “ Gas Light and Coke Com—
pany," for making inﬂammable air for the lighting of the streets of
the metropolis, ism—Session 1810, 50th Geo. III.

(45)

NATURAL HISTORY

AND

CHEMICAL CONSTITUTION 0F COAL
WITH REMARKS

ON THE

ECONOMY OF THIS KIND OF FUEL.

PIT-COAL exists in this island in strata, Which, as
far as concerns many hundred generations after
us, may be pronounced inexhaustible; and is so
admirably adapted, both for domestic purposes
and the uses of the arts, that it is justly regarded
as a most essential constituent of our national
wealth. Like all other .bituminous substances,
it is composed of a ﬁxed carbonaceous base or
bitumen, united to more or less earthy and saline
matter constituting the ashes left behind when
this substance is burnt. The proportions of these
parts differ considerably, in different kinds of
coal; and according to the prevalency of one
or other of them, so the coal is more or less com-
bustible, and possesses the character of perfect

46 A TREATISE 0N GAS-LIGHT.

pit-c011]; and by various shades, passes from‘the
most inﬂammable canel-coal, into blind, Kilken-
ny, or stone-coal; and, lastly, into a variety of
earthy or stony substances ; which, although they
are inﬂammable, do not merit the appellation
of coal, hence pit coals may be divided into the
following classes.

The ﬁrst class comprehends those varieties of
coal which are chieﬂy composed of asphaltum or
bitumen, which take ﬁre easily and burn briskly
witha‘brilliant, bright, strong, and yellowish white
blaze from beginning to end, which do not swell
or coke on the ﬁre ; which require no stirring ;
which produce no slag, and by a single combus-
tion are reduced to extremely light white ashes.
Most of this class of coal when suddenly heated,
crackle, and split into pieces, especially if not
laid on the ﬁre in the direction of the cross frac-
ture of their laminae.

The coals found at Wiggan, in Lancashire, and
most of those raised on the western coast of En-
gland, belong to this class. Canel-coul deserves
to be placed at the head of this class of coals.
It occurs occasionally in the Newcastle coal-pits.
The Scotch splent coal is a coarse variety of
camel—coal ; indeed, most of the Scotch coals are
ofthis kind. This class of coal is well adapted
for the gas-light illumination. It requires less

i

A runnrssn ON GAS LIGHT. 47

heat to be carbonized than Newcastle coal. The
gas which it produces is readily puriﬁed._ It
yields also during combustion the least’sQuantity
of sulphuretted hydrogen, and gives a white bril-
liant light.

This class of coal passes into a vast number
of sub-species or varieties. The coals known in
the London market, by the names of Hartley,
Cowper’s Main, Tanﬁeld Moor, Eighton Main,
Blythe, Pontops, are when chemically consigered
evidently of this class of coal. They usually are
offered for sale in larger masses, than the other
classes of coals.

The second class of coals comprehend all those
varieties which contain upon the whole a less quan-
tity of bitumen, and. a larger quantity of carbon
than the ﬁrst class. They burn with a ﬂame less
bright, and of a yellowish colour: after having
lain on the ﬁre for some time, they become soft,
swell and pass into a state of semi-fusion; they
then cohere and coke, puff PP, and throw out
tubercular scoriae accompanied with small jets of
ﬂame with a hissing noise.

In consequence of the agglutination and tume-
faction, the passage of air, if the coal be burnt
in an open grate, is interrupted, the ﬁre burns as
it is called, hollow, and would become extin-
guished, if the tap, of ’ the coal were not from time

48‘ ' A TREATISE ON GAS-LIGHT.

. .. to time broken into with the poker. The pro—

duce of ashes which these coals aﬂ'ord, is smaller,
heavierthan those of the ﬁrst class and of :‘
grey or reddish colour. These coals afford a
porous hard grey scoriae or Cinders, which being

burnt over again with fresh portions of coal give

out an intense and lasting heat. The colour of
the ﬂame of this class of coal, is never so white
and brilliant as the ﬂame of the ﬁrst class: the
last bortion of ﬂame which they produce after
all the bituminous part is disengaged, is always
of a lambent blue colour; and the gas which
they produce, during this state of combustion, is
chieﬂy gazeous oxid of carbon mixed with a por-
tion of hydrogen and carbonic acid. The coke
which these coals aﬂbrd is more compact than
that produced by the ﬁrst class, and is excel-
lently calculated for standing the blast of the bel-
lows in metallurgical operations. The coals
belonging to this class are called in the market
strong burning coals. The difference of speciﬁc
gravity of a sack of this kind of coal compared
with all the other varieties met with in the coal
market, is from 28 to 30lb. per sack. The so
called Wall’s End coals deserve to be placed at
the head of this class. The following varieties
are suﬂiciently known, Russel‘s Wall End, Bell’s
Wall End, Bewick’s Wall End, Brown’s \Vall

A TREATISE ON GAS-LIGHT. g 49

End, Wellington Main, Temple Main, Heaton
Main, Killingsworth Main. The smaller kind!
of coals of this class are preferred by smiths,
because they stand the blast, they give the great
est heat and best Cinders. The Swansea coals
also belong to this class; some varieties abound
in pyrites, others are intersected with thin layers
of lime-stone and shell, these substances present
themselves as slates or stones among the ashes
which they afford. They require more heat for
being carbonized then the ﬁrst class; and the
carburetted hydrogen gas which they aﬂ'ord is
usually loaded with sulphuretted hydrogen. The
ﬂuid obtained from them by distillation, con-
tains a considerable portion of sulphate, carbonate
and hydrosulphuret of ammonia.

A due mixture of this and the former class of
coals produces the most economical and‘ best
fuel for domestic and culinary purposes, two
parts of strong or caking coal of class No.2,
mixed with one part of light burning or blazing
coal of class No. 1, forms an excellent fuel. As
the proportion of the light or blazing coal in-
creases, the fuel becomes more readily managed
and more cheaiful as is usually called; but its
duration and intensity of heat also decreases in
the same proportion.

The third class of pit-coal are those, which are

H

50 g A TREATISE 0N GAS-LIGHT.

almost destitute of bitumen, being chieﬂy com-
posed of carbon in a peculiar state of aggrega-
tion, evidenﬁr combined chemically with much
earthy matter. This class of coal requires a still
higher temperature to become ignited than any of
the former classes: they emit little or no smoke.
when laid on a ﬁre they burn away with a feeble
lambent ﬂame, indeed, some varieties give no
ﬂame at all, but burn merely with a red glow,
almost like charcoal, and at length become con-
sumed without caking. They leave but a small
portion of heavy ashes. When submitted to dis-
tillation they afford no tar, or at least a small
quantity only, and of a consistence almost resem-
bling pitch, and a gazeous ﬂuid chieﬂy composed
of gazeous oxid of carbon and hydrogen gas.
Hence they cannot be employed in the manufac-
ture of coal gas. The coke which they aﬂ‘ord
is nevertheless excellent. The Kilkenny coal,
Welch coal, and Stone coal belong to this class.

With regard to the origin or formation of coal
the most widely different opinions have been held,
and by those too, who have been the most com-
petent to form a proper judgment.

The great speciﬁc gravity, hardness, texture,
and inconsiderable degree of combustibility which
some kind of coal possesses, such as stone coal,
for example, has led many able mineralogists to

A 'I‘REATISE ON GAS-LIGHT. .. 51

conclude that coal is an earthy substance highly \
impregnated with petroleum and bitumen.

Others have been of Opinion," that pit-coal is
entirely of marine origin, and formed by the se—
baceous matter which have proceeded from the
innumerable tribes of animals which have peopled
the ocean. This mass of matter is supposed to
have accumulated and at last to have become
covered by various strata in consequence of the
different changes which the surface of the earth,
and the receptacles of the waters of the ocean
have experienced. Such is the opinion of Dr.
Hutton; be persuaded himself that coal thus ori-
ginated. from the deposition (as he calls it) of
fatty matters originating from the dissolution of
the various animals, and partly vegetable bodies
which are continually perishing on the surface of
the earth and in the waters of the sea.

Again others have laboured to prove that our
present coal strata originated from the decompo-
sition or disintegration of certain mountains. Mr.
Kirwan is of that opinion.

Waving as foreign to the objects of this trea-
tise, observations concerning the merit of these
opinions, and to which might be added many
others, we shall merely notice that the opinion
which the strictest examination of every circum-
stance seems best to warrant the adoption of,

52 A TREATISE ON GAS-LIGHT.

appears to be, that coal is a product of the vege-
table kingdom ; and when the different facts are
considered with regard to the situation of coal and
the various strata interposed between its several
beds, which have evidently been produced by
gradual deposition in water, no glaring incongru-
ity appears in the opinion that pit-coal is of sub-
marine origin. From the abundant vestiges of
vegetable remains with which coal strata abound,
the l‘igneous feature whichfrequently is presented
to our View in the most compact species, and
from the regular and gradual transition of bitumi-
nized wood to the more or less perfect coal, we
are certainly warranted to believe that this sub-
stance is of vegetable origin. 1

As to the precise mode and agent by which
the process of carbonization has been brought
about, the manner in which, and the period when
the successive strata which accompany coal have
been deposited, there exists, and probably ever
will exist, various theories more or less injurious
and consistent, which, although, in all probability
is very remote from the truth, are valuable as
exciting further enquiry, and as convenient me-
thods of arranging and collecting many curious
and important geological facts. To enter into
these would be deviating too far from the object
in view.

A TREATISE ON GAS-LIGHT. 53

To give an idea how long there is a probability
of Great Britain being supplied with coal from
the rivers Tyne and Wear only, it must be ob-
served:

lst. That the seams of coal which are now
worked at Newcastle and Sunderland, are equal
to a seam or bed of 15 miles by ‘20 miles.

2dly. That this seam, on an average, is at least
four feet and a half thick. ‘

3diy. That 1:6tl1 part of the above extent is
sufﬁcient for pillars to support the roofs of the
mines, &c.

And, 4thly. It appears, by experiment, that a
cubic yard of coal weighs 1 ton, or 20'cwt.

London Chaldrons.

The total consumption of coal from
the rivers Tyne and VVeare, known from
the register to be - - - — 2,300,000

The number of tons in the above
quantity, taking the London chaldron
at 27 cwt. is - - — -

3,100,000
Now a ton weight of coal is estimat-

ed to occupy in the earth the space of

one cubic yard.
The number of Cubic yards in a

square mile is — — ~ - 3,097,600
The beds or seams of coal are, on

an average, 4 feet and a half in thick—

54 A TREATISE ON GAS-LIGHT.

London Chaldrom.

ness, which increases the above number
of cubic yards in the square mile by
half the number of square yards to
And hence the square mile ‘of the
beds or seams of coal we are describ-
ing contains, of cubic yards and tons
of coal . -' - - - -
A deduction of l—6th for pillars to
support the mine, &c. - - - 800,000
The number of tons per square mile 5,445,000
We have already‘ mentioned the length and
breadth of the seams of coal to be equal to 20
miles by 15, making an area of 300 square miles,
and consequently a source of consumption for
375 years.

1,548,800

4,645,000

With regard to the economy of this kind of
fuel, or the quantity of heat produced during the 7
combustion of any given quantity of coal, or in-
deed, of any kind of fuel depends much upon the
management of the ﬁre, or the manner in which
the coal is burnt. When the ﬁre burns bright,
clear, and without smoke, much radient heat will
be sent oﬂ‘ from it; but when it is smothered up,
very little will be generated: most of the heat
produced will then be expended in giving elasti-
city to a thick dense vapour, or smoke, which is
seen rising from the ﬁre; and the combustion

A TREATISE 0N GAS-LIGHT. 55

being very incomplete, the carburetted hydrogen
gas of the coal being. driven up the chimney with—
out being inﬂamed, the fuel is wasted to little pur-
pose. ,

Nothing can be more perfectly devoid of com-
mon sense, and wasteful and slovenly at the
same time, than the manner in which chimney
ﬁres, where coals are burnt, are commonly ma-
naged by servants. They throw on a load of
small coals at once, through which the ﬂame is,
hours in. making its way; and frequently it is not
without much care and trouble that the ﬁre is
prevented from going quite out. During this
time no heat is communicated to the room; and,
what is still worse, the throat of the chimney
being occupied merely by a heavy dense vapour,
not possessed of any heating power, and, con-
sequently not having much elasticity, the warm
air of the room ﬁnds less difﬁculty in forcing its
way up the chimney and escaping, than when the
ﬁre burns bright, and the coal is ignited. And it
happens not unfrequently, especially in chimnies
and ﬁre-places ill constructed, that this current of
warm air from the room which presses into the
chimney, crossing upon the current of heavy
smoke and aqueous vapour which escapes slowly
from the ﬁre, obstructs it in its ascent, and beats
it back into the room. Hence it is that chimnies

56 A TREATISE 0N GAS-LIGHT

so often smoke when too large a quantity of fresh
coals is put upon the ﬁre. So many coals should
never be put on the ﬁre at once, as to prevent the
free passage of the ﬂame between them, or to
prevent them becoming quickly heated, so as to
give out the carburetted hydrogen gas which they
are capable of furnishing, and to cause it to be
inﬂamed. In short, a ﬁre should never be smo-
thered: and when attention is paid to the quan—
tity of coals put on, there is little use for the
poker; and this circumstance will contribute
much to cleanliness, and the preservation of fur-
niture. '

The author of a paper in the Plain Dealer
asserts, that, of the various perversions of abili—
ties, there is none that makes a human being
more ridiculous, than that of attempting to stir a
ﬁre without judgment; to prevent which he lays
down the following rules :—1. Stirring of a ﬁre
is of use, because it makes a hollow where, the
air being rareﬁed by the adjacent heat, the sur-
rounding air rushes into this hollow, and gives
life and support to the ﬁre, and carries the ﬂame
with it. 2. Never stir a ﬁre when fresh coals are
laid on, particularly when they are very small,
because they immediately fall into the hollow
place, and therefore ruin the ﬁre. 3. Always
keep the bottom bars clear. 4. Never begin to

A TREATISE ON GAS-LIGHT. 57

stir the ﬁre at the top, unless when the bottom is
quite clear, and the top only wants breaking.

As we have seen what is necessary to the pro-
duction and generation of radiant heat, it remains
to determine how the greatest proportion of it
generated and sent off from the ﬁre in all direc-
tions may be made to enter the room and assist
in warming it. Now, as the rays which are
thrown off ﬁ‘om burning fuel have this property
that they generate heat only when and where
they are stopped or absorbed, and also in being
capable of being reﬂected without generating
heat at the surfaces of various bodies, the know-
ledge of these prOperties will enable us to take
measures with certainty for producing the effect
required; that is, for bringing as much radiant
heat as possible into the room.

This must be done, ﬁrst, by causing as many
as possible of the rays, as there are sent oﬂ‘ from
the ﬁre, to come directly into the room; which
can only be effected by bringing the ﬁre as far for-
ward as possible, and leaving the opening of the
ﬁre-place as wide and as high as can be done
without inconvenience; and secondly, by making
the sides and the back of the ﬁre-place of such
form, and constructing them of such materials, as
to cause the direct rays from the ﬁre, which

I

58 A TREATISE 0N GAS-LIGHT.

strike against them, to be sent into the room by
reﬂection in the greatest abundance.

It will be found that the best form for the ver-
tical sides of a ﬁre-place, or the covings, as they
are called, is that of an upright plane, making an
angle with the plane of the back of the ﬁre—place
\of about 135 degrees. According to the usual
construction of chimnies, this angle is ninety de-
grees, or forms a right angle; but as in this case
the two sides or covings of the ﬁre-place, are
parallel to each other, it is evident that they are
very ill contrived for throwing into the room, by
reﬂection, the rays from the fire which fall on
them. Whereas the back of the ﬁre-place ought to
be only about one-third of the width of the opening
of the ﬁre-place in front, and, consequently, that
the two sides or covings of the ﬁre-place, in-
stead of being perpendicular to the back, are
inclined to it at an angle of about 135 degrees;
and in consequence of this position, instead of
being parallel to each other, each of them pre-
sents an oblique front towards the opening of
the chimney, by means of which, the rays which
they reﬂect are thrown into the room.

In regard to the materials which it will he most
advantageous to employ in the construction of
ﬁre-places, no great difﬁculty will attend the de-

A TREATISE ON GAS-LIGHT. 59

termination of that point. As the object in view
is to bring radiant heat into the room, it is Clea-i:
that that material is best for the construction of
a ﬁre-place which reﬂects the most, or which ab-
sorbs the least of it; for that heat which is ab-
sorbed cannot be reﬂected. As bodies which
absorb radiant heat are necessarily heated in
consequence of that absorption, the materials that
can be employed for constructing ﬁre-places are
best adapted for that purpose, we have only to
ﬁnd, by a very easy experiment, what bodies ac-
quire least heat when exposed to the direct rays
of a clear ﬁre; for those which are least heated
evidently absorb the least, and consequently re-
ﬂect the most radiant heat. And hence it appears
that iron, and, in general, metals of all kinds,
which are well known to grow very hot, when
exposed to the rays projected by burning fuel,
are to be reckoned among the very worst materi-
als that it is possible to employ in the construc-
tion of ﬁre-places of all kinds.

The best materials are ﬁre-stone, and common
bricks and mortar, which are fortunately very
cheap.

k When bricks are used they should be covered
with a thin coating of cement, and every part
of the ﬁre-place, which is not exposed to being
soiled and made black by the smoke, should be

60 A mums: on! GAS-LIGHT.

kept polished as much as possible. The current
.‘ air, going under the mantle into the chimney,
should be made gradually to bend its course
upwards, whereby it will unite quickly with the
ascending smoke, and be less likely to check it,
and repel it into the room. This may easily, and
should always, be effected by rounding 011' the
breast of the chimney, or back of the mantle,
instead of leaving it ﬂat, or full of corners or
holes. The height to which the covings and back
ought to be carried, will depend not only on the
height of the mantle, but particularly on the
height of the chimney breast, or that part Where
the breast ends and the upright canal begins.
The backward covings must rise ﬁve or six inches
higher thanvthis part, to form properly the throat.
Therepis no advantage to carry them up higher.

The best width for the throat of a chimney, is
four inches; three may do when the tire-place is
small and the chimney good and well situated;
but, to prevent the accidental puffs of smoke, some-
times made by putting on much coals too sud-
denly, and when the throats may be very narrow,
it has been found that upon the whole, four in-
ches are best for a ﬁre-place to burn coal. In ﬁre-
places for large halls, &c. it may be increased to
ﬁve or six inches.

The proper width of grates designed for mid-

A TREATISE 0N GAS-LIGHT. 6)

dling sized rooms is six to nine inches, and their
length may be diminished more or less, according
as the room is heated with more or less difﬁculty,
or as" the weather is more or less severe. When
the width of a grate is not more than ﬁve inches,
it will be very difﬁcult to prevent the ﬁre going
out.

Another important subject in the economy of
heat, is, the size of the coal. It is not generally
apprehended, how very wasteful the use of small
coals is in the ordinary open ﬁre-grates. Neces-
sity makes us use the poker, particularly, when
the coals are small; and habit prevails even when
they are large. By the constant stirring of the
ﬁre, almost the whole of the small coal passes
through the bars; and consequently a great deal
goes to the dust-hole Without being burnt at all.
To prove this, we need only take a shovel full of
ashes and put them into a pail, and then pouring
water over them, which being gently run off, will
carry nearly all the light and burnt parts: and
leave an astonishing quantityr of bright unburnt
coal, which has escaped from the ﬁre-place, in
consequence of being small.

When the grate of the ﬁre-place is large, and
the small coals are thrown behind; or when we
can have patience enough to bear the cold for
an hour or two, or contrive to have the ﬁre

62 A TREATISE ON GAS-LIGHT.

livhted along time before we want it, the small
coal may be of some use; but the ﬁre made with
it is never strong, nor so bright; and does not
burn so long as a ﬁre made with large or round
coals: it often requires the help, of the poker, and
produces a great quantity of breeze.

The loss in the use of small coals is more con
siderable to the poor, who cannot keep large
ﬁres. When they want their breakfast or dinner,
the time they can spare is limited; and to have
their water Seoner boiling, or their meals quicker
ready; they must make use of the poker, and
lose a great deal of coal. This fact is so evident,
that any body who wishes to make the experi-
ment before recommended, will ﬁnd that much
more bright coal goes to the dust-hole of the
poor man, than to the dust-hole of a rich family,
where, the ﬁre-place being large, the small coal
has more chance of burning.

The loss is still greater to the poor, in conse-
quence of the inferior sorts of coal which are sold
to them. If it is the light sort, it burns too quick,
and they consume double the quantity; if the
strong sort, it burns too slow, and is nearly as
wasteful; for a great quantity of it then goes to
the dust-hole without having been lighted at all.

An incorrect opinion is often entertained, that

the real quantity of coal contained. in a sack is

A TREATISE 0N GAS-LIGHT. 63

lessened by separating or screening the (small
from the round coals; but we must recollect, that
any compact body occupies less space than is
required to contain the same matter, reduced to
smaller irregular pieces, or to powder.——Now the
screening only takes away the ﬁnest duSty part

of the coals and admits more small pieces of
round coals to be ﬁlled into the sack.

a

l

t

n

a
n

“ And with regard to the measure of coal* as
offered in the market, it may be remarked that
many coal-merchants will promise to give 68
sacks to a room; but here it should be ob-
served, that much depends on the size and
shape, or, as it is called, the roundness of the
coal, viz. any of the \Vall’s End, .Wellington,
Benton, Heaton, Heborn, Percy-Main, Cow-
per, Blyth and Hartley, being all put on board
of ships in large masses and blocks, round as
out of the mine; it is certain, that in every
room of ﬁve chaldron and a half the ingrain,
when the round is broken, every room will
measure out from 6 to 65 chaldron again,
equal to 72 or 73 sacks; those of the inferior
kind being so small, will barely measure out
the same measure as they meted in the pool.
It is now become a general rule when a room

*Edington on the Coal Trade, p. 91, 92. 93.

64 A TREATISE ON GAS-LIGHT.

6‘

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‘

Os

l‘

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¢

¢

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Is
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of coals is bespoke, to send in 63 sacks and no
more, with the meters ticket, which if fairly
measured, is all that can be expected; the
pverplus the merchant claims himself.

“ In coal-sheds the measure as well as the
mixing one kind of coal with another is often
scandalous, for the act of parliament does not
take the least notice of the small measures.
It is a known fact when a fraudulent dealer
orders in a room of coals, for every chaldrou
0f 36 bushels, if he does not send them out at
the rate of 42 bushels again, he will be dis-
satisﬁed with his measure. This is extremely
hard upon the lower class of people, who are
only able to purchase a peck, or half a peek, '
at a time; and let the measure be ever so bad,
they have no means of redress.

“ But should the legislature determine to do
away the present erroneous mode of measur-
ing coals, in which the deception betWeeu
round and small coals is so great, there is no
way completely to remove the evil, but to have
them sold by weight, in preportion, which would
put it out of the power of the seller to defraud,
even in the. smallest quantity; and as to the
coal-waggons, instead of carrying the bushel
measure they use, let them have a pair of steel-
yards, so that a sack, or any quantity of sacks

a
a

A TREATISE 0N GAS-LIGHT. 65

of coal could be easily weighed at the over-end
of the waggon, and if the sack of coals weigh
255 pounds after deducting the sack, the pur—
chaser may be satisﬁed that he has his mea-
sure.” )

Mr. Edington observes,‘ that “ the difference
is so great between round coals; with regard to
absolute quantity, and small damp and dry
coals, that no means can be obtained to correct
and prevent abuse. Thus if a vat of Wall’s
End coals be measured from the ship, such
measure as the meter gives,——turn over the vat,
and break the round coals to the size the mer—
chant sends them out to his customers, then
ﬁll up the vat again, and it will be found to
over-run a bushel, more or less according to the
roundness of the coal. Secondly, a score is
measured out of VVall’s End coals in the pool,
into a barge having four rooms, each containing
ﬁve chaldrons and a half the ingrain; no sooner
does the barge arrive at the wharf, than the
round coals are broken, and if very dry, the coals
being wetted, will increase in bulk; nor is the
coal-merchant satisﬁed if he does not by this
practice send out from six to six and a quarter,

"' Edington’s Treatise on the Coal Trade, p. 191, 192, and 200.
K

66 A TREATISE 0N OAS-LIGHT.

“ or even six and a half chaldrons from each room.

‘6

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rs

Thirdly, if coals were sent out by weight the
deception by watering them may be supposed to
be heavier, but the contrary is the case; for if a
bushel of \Vall’s End coals be measured up dry
it will shew its weight to be from 84 to 85lb.
then try another bushel of the same coals well
Wetted, the weight will be. found not so great;
for the fact is, a bushel of dry coals, if ever so
round, has always a part small, which runs like
dry sand, and ﬁlls up every cavity, making the
whole a solid mass; whereas a bushel of wet
coals only closes up the hollow cavity, and they
clog together and will not weigh so much as
the dry coals. In meting coals by measure take
a bushel. of coals dry, turn them up and“ wet
them well, then ﬁll up the bushel again and they
willvover—run the measure considerably, for as
before observed, they ﬁll up hollows.

“ By the proposed method of adopting the sale
of coal, both weight and measurement, justice
would be done to the revenue, to the consumer
of coals, and to all coal-merchants and pr0pri-
etors of the collieries. But from the observa-
tions already shewn it is not to be wonder--
ed that the coal-merchants give so decided a
preference to the round coals, because the
larger they are, by breaking, &c. the greater

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‘¢

“

A TREATISE ON GAS-LIGHT. 67

the quantity will run over the measure they re-
ceive in the pool; nay, they see by the certiﬁ-
cates put up in the change on a market day, all
such ycargoes as are loaded by the spout only,
and they will give from 12d. to 18d. per chal—
dron, in preference to large cargoes, even of the
same coals; but from the size the ship being
obliged to take a part of her lading in by keel,
not so round as those wholly loaded by the

L”

SPODI.

(68)

THEORY

OF THE

0031B USTION 0F COAL,

IN

ELUCIDATION, 01? THE NATURE AND PRODUCTION

UP

GAS-LIGHT.

 

EVERY body knows that when pit-coals are
burning.in our grates, a ﬂame more or less lumi-
nous issues from them, and that they frequently
emit beautiful streams of ﬂame remarkably bright.
But besides the ﬂame, which is a peculiar gas in
the state of combustion, heat expels from coal an
aqueous vapour, loaded with several kinds of
ammoniacal salts, a thick viscid ﬂuid resembling
tar, and some gases that are not of a combusti-
ble nature. The consequence of which is, that
the ﬂame of a coal-ﬁre is continually wavering and
changing, both in shape, as well as brilliance and
in colour, so that what one moment gave a beauti-
ful bright light, in. the next, perhaps, is obscured
by a stream of thiek smoke,

A TREATISE 0N GAS LIGHT. 69

But if coals, instead of being suffered to burn
in this way, are submitted to distillation in close
vessels, all its immediate constituent parts may be
collected. The bituminOus part is melted out in
the form of tar. There is disengaged at the
same time, a large quantity of an aqueous ﬂuid,
contaminated with a portion of oil, and various
ammonical salts. A large quantity of carburet-
ted hydrogen, and other uninﬂammable gases,
make their appearance, and the ﬁxed base of the
coal remains behind in the distillatory apparatus
in the form of a carbonaceous substance, called
coke. .

All these products may be separately collected.
in different vessels. The carburetted hydrogen, or
coal-gas, may be freed from the non-inﬂammable
gases, and afterwards forced in streams out of
small apertures, which, when lighted, may serve
as the ﬂame of a candle to illuminate a room or
any other place. It is thus, that from pit—coal a
native production of this country, we may pro-
cure a pure, lasting, and copious light; which, in
other cases, must be derived from expensive mate-
rials, in part imported from abroad.

It is chieﬂy upon the power of collecting the
products aﬁbrded by coal, with convenience and
cheapness, that the promoters of the gas-light illu-
mination found 'their claims to publicencourage-

70 ' A TREATISE ON GAS-LIGHT.

ment. They conceive that the ﬂame which pit-coal
yields, as it is now consumed, is turned to very
little advantage: it is not only conﬁned to one
place, where a red heat is more wanted than a
brilliant ﬂame, but it is obscured, and sometimes
entirely smothered, by the quantity of incombus-
tible materials that ascend along with it and pollute
the atmosphere. '

That much inﬂammable matter is thus lost, is
evident from facts that come under our daily ob-
servation. \Ve often see a ﬂame suddenly burst
from the densest smoke, and as suddenly disap-
pear; and if a light be applied to the little jets
that issue from the bituminous parts of the coal,
they will catch ﬁre, and burn with a bright ﬂame.
A considerable quantity of gazeous ﬂuid, capable
of aﬂbrding light and heat continually escapes up
the chimney, whilst another part is occasionally ig-
nited, and exhibits the phenomena of the ﬂame and
light of the tire.

The theory of the production of gas-light is
therefore analagous to the action of a lamp or
candle. The wick of a candle being surrounded
by the ﬂame, is in the same situation of the pit-
coal exposed to distillation. The ofﬁce of the
wick is chieﬂy to convey tallow, by capillary at-
traction, to the place of combustion. As it is de-
composed into carburetted hydrogen gas it is con-

, A TREATISE 0N GAS-LIGHT. 71

sumed and ﬂies off, another portion succeeds;
and in this way a continued current of tallow and
maintenance of ﬂame are effected.

_T his combustion of oil by means of a lamp de-
pends on similar circumstances. The tubes form—
ed by the Wick serve the same ofﬁce as a retort
placed in a heated furnace through which the
inﬂammable liquid is transmitted. The oil is
drawn up into these ignited Ltubes, and is decom-
posed into carburetted hydrogen gas, and from the
combustion of this gas the illumination proceeds.
What then does the gas-light system attempt?
Nothing more than to generate, by means of suf-
ﬁcient furnaces and a reservoir of sufﬁcient capa-
city, desired quantities of the gas, which is the
same material as the ﬂame of candles or lamps;
and then by passing it through pipes to any de-
sired distance, to exhibit it there at the mouths of
the conducting tubes, so that it may be ignited for
any desired purpose. The only difference between
this process and that of an ordinary candle or
lamp, consists in having the furnace at the manu—
factory, instead of its being in the wick of a can-
dle or lamp—in having the inﬂammable material
distilled at the station, instead of its present ex— /
hibitions in oil, wax, or tallow, and then in trans-
mitting the gas to any required distance, and
igniting it at the oriﬁce of the conducting pipe

72 A TRENI‘IISE 0N GAS-LIGHT.

instead of igniting it at the apex of the wick.
The principal is rational, and justiﬁed by the uni-
versal mode in which all light is produced. In-
deed, this discovery ranks among the numerous
recent applications of chemical science to the
purposes of life, which promise to be of the most
general utility.

It is evident from the outline here given of the
production and application of coal—gas, that all
the uses of pit-coal are not exhausted; it will be
sufﬁcient to observe, that the complete analysis of
coal, which has been hitherto conﬁned to the la-
boratory of the chemist, requiring skill and nicety
in the operator, and attended with great trouble
and expence, is now so far simpliﬁed, that many
chaldrons of coals may be decomposed by one
gas-light apparatus in the space of six hours, and
all the component parts produced in their most
useful shape, at an expence out of all proportion
below the value of the products.

(73y

SKETCH
0F

KW THE RISE AND PROGRESS

i; or THE

DISCOVERY AND APPLICATION

COAL-GAS,

AS A SUBSTITUTE FOR PROCURING

ARTIFICIAL LIGHT.

T0 assist the reader in comprehending the nature
and object of substituting coal-gas for tallow or
oil, for the purpose of obtaining light, it may be
proper to touch slightly upon the successive dis-
coveries that have been made as to the decompo-
sition of coal, and the application of its different
ingredients. Such a Sketch will add to the many
examples that occur in the history of science and
art, Showing the slow progress of mankind in fol-
lowing up known principles, or extracting from
acknowledged facts every possible advantage.

In the Philosophical Transactions of the Royal
Society, V. XLI. so long ago as the year 1739, is

L

74 A TREATISE 0N GAS-LIGHT.

recorded a paper, exhibiting an account of some
experiments made by Dr. James Clayton, from
which it appears that the inﬂammable nature of
coal-gas was then already known. Dr. Clayton
having distilled Newcastle coal, obtained, as pro-
ducts of the process, an aqueous ﬂuid, a black
oil, and an inﬂammable gas, which he caught in
bladders, and by pricking these he was enabled to
inﬂame the gas at pleasure.

It is further known, that in the beginning of the
last century, Dr. Hales’* on submitting pit-coal to
a chemical examination, found, that during the
ignition of this fossil in close vessels, nearly one
third of the coal became volatilized in the form of
an inﬂammable vapour. Hence the discovery of
the inﬂammable nature of coal-gas can no longer
be claimed by any person now living,

In the year 1767, the Bishop of Llandaﬂ‘T ex-
amined the nature of the vapour and gazeous
products evolved during the distillation of pit-coal,
This learned philos0pher noticed, that the volatile
product is not only inﬂammable as it issues from
the distillatory vessel, but that it also retained its
inﬂammability after having been made to pass
through water, and suffered to ascend through

‘ Vegetab. Statics, Vol.1.
1t Watson's Chemical Essays, VOLII.

A TREATISE ON GAS-LIGHT. 75

two high curved tubes. The solid matters ob-
tained by this venerable prelate, were, an aqueous
ammoniacal ﬂuid, a tenaeeous oil, resembling tar,
an ammoniacal liquor, and a spongy coal, or coke.

The ﬁrst discovery and application of the use
of coal-gas for the purpose of illumination is
claimed by Mr. Murdoch.

Dr. W. Henry, of Manchester, has published
the following account* of this discovery.

“ In the year 1792, 'at which time Mr. Mun-
doch resided at Redruth, in Cornwall, be com-
menced a series of experiments upon the quantity
and quality of the gases contained in different
substances. In the course of these he remarked,
that the gas obtained by distillation from coal,
peat, wood, and other inﬂammable substances,
burnt with great brilliancy upon being set ﬁre to;
and it occurred to him, that by conﬁning. and con-
ducting it through 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 c0p-
per tubes to the distance of 70 feet. At this ter-
mination, as well as at intermediate points, the gas
was set ﬁre to, as it passed through apertures of
different diameters and forms, purposely varied

* Thompson’s System of Chemistry, Vol. I. p. 52.

76 A TREATISE 0N GAS-LIGHT.

With a view of ascertaining which would answer
best. In some the gas issued through a number
of small holes like the head of a watering pan;
in others it was thrown out in thin long sheets;
and again in others in circular ones, upon the
principle of Argand’s lamp. Bags of leather and
of varnished silk, bladders, and vessels of tinned
iron, were ﬁlled with the gas, which was set ﬁre
to, and carried about from room to room, with a
view of ascertaining how far it could be made to
answer the 'purpose of a moveable or transferable
light. Trials were likewise made of the different
quantities and qualities of gas produced by coals
of various descriptions, such as the Swansea,
Haverfordwest, Newcastle, Shropshire, Staﬂ‘ord-
shire, and sdme kinds of Scotch coals.

“ Mr. Murdoch's constant occupations pre—
vented his giving farther attention to the subject
at that time; but he again availed himself of a
moment of leisure to repeat his experiments upon
coal and peat at Old Cumnock, in Ayrshire, in
1,797; and it maybe proper to notice that both
these, and the former ones, were exhibited to nu-
merous spectators, who, if necessary, can attest
them. In 1798, he constructed an apparatus at
Soho Foundry, which was applied during many
successive nights to the lighting of the building;
when the experiments upon ditlerent apertures

A TREATISE ON GAS-LIGHT 77

were repeated and extended upon a large scale.
Various methods were also practised of washing
and purifying the air, to get rid of the smoke and
smell. These experiments were continued, with
occasional interruptions, until the epoch of the
peace in the spring of 1802, when the illumination
of the Soho manufactory afforded an opportunity
of making a public display of the new lights; and
they were made to constitute a principal feature
in that exhibition.” ‘

,7In the year 1803 and 1804, Mr. Winsor exhi-
bited at the Lyceum, in London, the general nature
of this new mode of illumination though the ma-
chinery for procuring, and the manner of purifying
the gas, he kept a secret. He exhibited the mode
of conducting the gas through the house, and a
number of devices for chandeliers, lamps, and
‘ burners, by which it might be applied. Among
these he proposed long ﬂexible tubes suspended
from the ceiling, or wall of the room, and at the
end communicating with burners or lamps of dif-
ferent kinds. This gentleman showed also by
experiment, that the ﬂame of the gas-light pro-
luced no smoke; that it was not so dangerous as
the ﬂame of candles or lamps; that it could not
produce sparks; and that it was not so readily
extinguished by gusts of Wind or torrents of
“am.

78 A 'TREATISE 0N GAS-LIGHT.

Mr. WINson’s display of gas-lights took place
more than two years before Mr. MURDocn’s prio-
rity of right was heard of.

In stating these facts I do not mean to say
that Mr. MURDOCH derived the hint of applying
the coal-gas from the previous exhibition of Mr.
WINSOR, because it is quite within the bounds of
probability that the ideas of Mr. MURDOCH may
have arisen totally independent of all acquaint-
ance with Mr. VVINson‘s.

The claims of invention, or the determination
of the right of priority, concerns the public only
so far as the honour and estimation of any useful
discovery conferred on the inventor, may induce
other individuals to devote their talents to similar
pursuits; by means of which, more discoveries
may be made, and the subject of human inven-
tion become extended, or rendered more useful.
For as to the mere beneﬁts which mankind may de-
rive from any particular discovery, they are cer-
tainly more indebted to the person who ﬁrst
applied the discovei'y to actual practice, than to
him who ﬁrst made it, and merely illustrated it
by barren experiments. Mr. \VINSOR certainly
pressed on the mind of the public with unre-
mitted perseverance and diligence, the extensive
application of gas-lightin the year 1802, but he
made no new discovery with regard to the com-

A TREATISE ON GAS-LIGHT. 79

0

position of coal; he did not even invent the mode
of conducting the gas through tubes; and if he
has pointed out the particulars of the process, he
has made a very important, though not the most
brilliant, improvementin this line of business. Mr.
WINson’s publications are, perhaps, but ill adapt-
ed to promote his cause; and the exaggerated
calculation which the sanguine mind of a disco-
verer is naturally disposed to indulge in, have, to
superﬁcial observers, thrown an air of ridicule ‘
and improbability on the whole scheme of light-
ing with gas.

It may, however, be safely afﬁrmed, that if the
same facts had come forward under the sanction,
of some great name in the chemical or philosophi-
cal world, the public incredulity'would, long since
have been subdued; and- the plan, which for
many years has been struggling for existence,
would have been eagerly adopted as anational
object.

On the 18th of May, 1804, Mr. WINSOR, took
out a patent for combining the saving and purify-
ing of the inﬂammable gas (for producing light
and heat), the ammonia, tar, and other products
of pit-coal, with the manufacture of a superior
kind of coke (see Repertory, 2d Series, v. 17?).
And, lately, the same gentleman has taken out a

80 A TREATISE ON GAS‘LIGHT.

secohd patent, for further improvements in these
processes.

In the year 1805, Mr. NORTHERN, of Leeds
also directed the attention of the public to the
application of coal-gas, as a substitute for tallow
light, as will be seen by the following extract of
the Monthly Magazine, for April, 1805.

“ I distilled in a retort, 50 ounces of pit-coal
in a red heat; which gave 6 ounces of a liquid
matter covered with oil, more or less ﬂuid as the
heat was increased or diminished. About 26
ounces of cinder remained in the retort; the rest
came over in the form of air, as it was collected
in the pneumatic apparatus. I mixed part of it
with atmospherical air, and ﬁred it with the elec-
tric spar‘k with a tolerable explosion, which proves
it to be hydrogen—\Vhether any of the other
gases were mixed with it, I did not then deter-
mine. In the receiver I found a ﬂuid of an acid
taste, with a great quantity of oil, and at the bot-
tom, a substance resembling tar.

“ The apparatus I make use of for producing
light is a reﬁner’s crucible, the top of which (after
ﬁlling with coal) I close with a metal cover, luted
with clay or other luting, so as to prevent the es-
cape of the gas; a metal pipe is soldered into the
cover, bent so as to come under the shelf in the

A TREATISE on GAS-LIGHT. 31

pneumatic trough, over which I place a jar with
a stop-cock and a small tube; the jar being pre-
viously ﬁlled with water, the crucible I place on
the common or other ﬁre as is most convenient;
and as the heat increases in it, the gas is forced
rapidly through the water into the jar, and regu-
larly displaces it. I then open the cock and put
ﬁre to the gas, which makes its escape through
the small tube, and immediately a most beautiful
ﬂame ensues, perfectly free from smoke or smell
of any kind. A larger light, but not so vivid or
clear, will be produced without passing the gas
through water, but attended with a smoke some-
what greater than that of a lamp charged with
common oil. _

“ I have great hopes that some active mechanic.
or chemist will, in the end, hit on a plan to pro-
duce light for large factories, and other purposes,
at a much less expence, by the above or similar
means, than is at present produced from oil.”

Soon afterwards, Mr. SAMUEL CLEG*, of Man-
chester, Engineer, communicated an account of his
method of lighting up manufactories with gas-
light to the Society of Arts, for'which he received
the silver medal. —

Since that time, the application of gas-light
has spread rapidly, and numerous manufacto—

° This gentleman is at present engineer to the Gas-Light Company.
' M

82 A TREATISE 0N GAS-LIGHT.

nes and other establishments haveﬁbeen lighted
by coal-gas.

In France, the application of gas-lights to eco-
nomical purposes, was pointed out long before it
was publicly introduced into this country. M.
LE BON had a house ﬁtted up in Paris, in the
winter of 1802, so as to be entirely illuminated by
gas-lights, which was seen by thousands with ad-
miration; and had a brevet d‘invention (patent)
granted to him by the French government, for the
art of producing light from wood, ignited in close
vessels.

Many other attempts have been made to derive
advantage from the different ingredients of coal
but they are too obscure to merit particular enué
meration.

In the year 1808, Mr. MURDOCH presented to
the Royal Society his account of the application
of gas-light, and was complimented with Count
RUMFORD’S medal for the same.

The following statement is taken from Mr.
MURDOCH's paper.

“ The whole of the rooms of the cotton mill
of Mr. LEE, at Manchester, which is I believe
the most extensivein the United Kingdom, as well
as its counting—houses and store-rooms, and the
adjacent dwelling house of Mr. LEE, arelighted
with the gas from coal. The total quantlty of

A TREATISE ON GAS-LIGHT. 83

light used during the hours of burning has been
ascertained, by a comparison of shadows, to be
about equal to the light which 2500 mould can-
dles, of six to the pound, would give; each of the
candles with which the comparison was made
consuming 4-10ths of an ounce (175 grains) of
tallow per hour.

“ The gas-burners are of two kinds: the one
is upon the principle of the Argand lamp, and
resembles it in appearance; the other is a small
curved tube with a conical end, having three cir-
cular apertures or perforations, of about a thir—
tieth of an inch in diameter, one at the point of
the cone, and two lateral ones, through which the
gas issues, forming three divergent jets of ﬂame,
somewhat like a ﬂeur—de-lis. The shape and ge-
neral appearance of this tube has procured it,
among the workmen, the name of the cockspur
burner.

“ The number of burners employed in all the
buildings amounts to 271 Argand, and 653 cock-
spurs, each of the former giving a light equal to
that of four candles of the description above—men-
tioned; and each of the latter a light equal to
two and a quarter of the same candles; making
therefore the total of the gas-light a little more
than equal to that of 2500 candles, six to the
pound. When thus regulated, the whole of the

84 A TREATISE ON GAS—LIGHT.

above burners require an hourly supply of 1250
cubic feet of the gas produced from cannel-coal;
the superior quality and quantity of the gas pro-
dated from that material having given it a decided
preference in this situation over every other coal,
notwithstanding its higher price.

“ The time during which the gas-light is used
may, upon an average of the whole year, be
stated at least at two hours per day of 2—1 hours.
In some mills, where there is over work, it will be
three hours; and in the fexv where night work is
still continued, nearly 1:2 hours. But taking two
hours per day as the. common average through-
out the year, the consumption in Messrs. Philips
and Lee’s mill will be 1250 x '2 —— 9500 cubic feet

of gas per day; to produce which 700 weight of

 

cannel-Coal is required in the retort. The price
of the best W iggan cannel-coal (the sort used) is
13%(]. per cwt. (225.6(1. per ton) delivered at the
mill, or say about eight shillings for the seven
hundred weight. Multiplying by the number of
working days in the year (313), the annual c011-
sumption of coal will be 110 tons, and its cost 1251.

“ About one-third of the above quantity, or
say forty tons of good common coal, value ten
shillings per ton, is required for fuel to heat the
retorts, the annual amount of which is :20].

“ The 110 tons of cannel-Coal, when distilled,

A TREATISE 0N GAS-LIGHT. 85

produced about ’70 tons of good coke, which is
sold upon the spot at ls. 4d. per cwt. and will
therefore amount annually to the sum of 93L

“ The quantity of tar produced from each ton
of. cannel-coal is from 11 to 12 ale gallons, mak-
ing a total annual produce of about 1250 ale gal-
lons, which not having been yet sold, its value
cannot be determined.

" The interest of the capital expended in the
necessary apparatus and buildings, together with
what is considered as an ample allowance for
wear and tear, is stated by Mr. LEE at about 5501.
per annum, in which some allowance is made for
this apparatus being made upon a scale adequate
to the supply of a still greater quantity of light,
than he has occasion to make use of. 7

Mr. LEE is of opinion that the cost of atten-
dance upon candles would be as much, if not
more, than upon the gas apparatus; so that, in
forming the comparison, nothing need be stated
upon. that score, on either side.

‘ The economical statement ﬁor one year, then
stands thus :

Cost of 110 tons of canneLeoa] - £ 125

Ditto of 40 tons of cennnon ditto, to

carbonise - - — - 20

In all 145

86 A T‘tEATISE 0N GAS-LIGHT.

Deduct the value of 70 tons of coke .6 93

The annual expenditure in coal, after
deducting the value of the coke, and
without allowing any thing for the tar,

is therefore - - . - - 5‘)
And the interest of capital sunk, and
wear and tear of apparatus - — 550

Making the total expence of the gas ap-
paratus per annum, about - - 600

“ That of candles, to give the same light, would
be about 20001. For each candle, consuming at
the rate of 4-10ths of an ounce of tallow per
hour, the 2500 candles burning, upon an average
of the year, two hours per day, would, at one
shilling per pound, the present price, amount to
nearly the sum of money above—mentioned.

“ If the comparison were made upon an average
of three hours per day, as in most cases, would
perhaps be nearer to the truth, and the tear and
wear remaining nearly the same as on the former
case, the whole cost would not exceed 6501. while
that of the tallow would be 30001.”

Mr. ACKERMAN in this metropolis, has shown
that the art of gas—light illumination is not con-
ﬁned to great manufactories, but that its advan-
tages are equally applicable to those on a mode-
derate scale. The whole of Mr ACKERMAN’S
establishment, his public library, warehouse, print

A TREATISE 0N GAS-LIGHT. 87

ing—oﬂices and work-shops, together with his
dwelling-house from the kitchen to the drawing-
room, has, for these four years past, been lighted
with gas, to the total exclusion of all other lights.
The result of the Whole of this proceeding Will

be obvious from the following letter:

To Mr. ACCUM.
SIR,

“ In answer to your request withregard to my gas—lights, which
I now have in my house, I take this mode of informing you, that I
charge two retorts with 2401bs. of coal, half cannel and half New-
castle, from which I extract 1000 cubic feet of gas. To obtain this
quantity of gas, when the retorts are cold, I use from 100 to 1101b.
of common coals; but when they are in a working state, that is
to say, when they are once red hot, the carbonising fuel amounts
to about 251b. per retort. The bulk of gas thus obtained sup-
plies 40 Argand’s lamps, of the large size, for four hours per
night, during ‘the long winter evenings, together with eight Ar-
gand‘s lamps and about 22 single cockspur burners, for three hours
per night, in addition to which my printers employ 16 cockspur bur-
ners for ten hours per day to heat their plates instead of charcoal
ﬁre. In the depth of winter we charge two rctorts per day: but
upon an average, we work 365 retorts in 365 days.

Now 365 retorts containing 120lb.of coal each, make 43800lb. which
is equal to ten chaldrons of N cwcastlc and eight tons of cannel coal.

10 chaldrons of Newcastle coals, at 655. make ............ _,£ 32 10 0
8 tons of cannel coal,“ (this coal is sold by weight) at 1008.

per ton .................................... . . . . . 40 0 0

7 chaldrons of common coals for carbonising, at 558. . . . l9 5 0

To wages paid the servant for attending the gas apparatus 30 0 0

Interest of money sunk ............................... . 30 o 0

The wear and tear of the gas-light apparatus I consider to
be equal to the wear and tear of lamps, candlesticks,
&c. employed for oil, tallow, &c. ‘ —---—--
Total expence of the gas-lights 151 15 0

DEDUCT.
23 chaldrons of coke, at 60s. per chaldron. . . . 69
Ammoniacal liquor................... ..... . 5
Tar ....................................... 6

Charcoal employed by the copper-plate printers
to heat their plates, which is now done with
the gas—light ﬂame, cost, annually .. . . .. . . . 25
Two chaldrons of coals minus used as fuel, for
wamiing the house, since the adoption of
the gas-lights, at 655. per chaldrou ..... G 10
111 10 0

._.__——

Nett expences of the gas-lights. . . .f 40 5 0

o

38 A TREATISE 0N GAS-LIGHT.

The lights used in my establishment, prior to the gas-ﬁghts
amounted annually to ............................ ,f 160 0 0
,My present system of lighting with gas costs, per anu. 40 5 o

 

Balance in favor of the gas for one year if 119 15 0

Such is the simple statement of my present system of lighting. the
brilliancy of which, when contrasted with our former lights, bears
the same comparison to them as a bright summer sun-shine does to a
murky November day: nor are we, as formerly. almost sull'ocated
with the eﬂluvia of charcoal and fumes of candles and lamps. In
addition to this, the damage sustained by the spilling of oil and tal-
low upon prints, drawings, books and papers, Ste. amounted annually
to upwards of 501. All the workmen employed in my establishment
consider their gas-lights as the greatest blessing; and I have only to
add, that the light we now enjoy, were it to be produced by means
of Argand's lamps or candles, would cost at least 3501. per annum.

I am with respect,
Strand, hiareh 13, Yours,
1815. ' ~ R ACKERMAN.

'.‘ Although cannel-coal sells at nearly double the price of Newcastle

cool, I use it in preference to the latter, because it afforded larger portion
of gas, and gives a much more brilliant light.

Another manufacturer who was one of the
ﬁrst that adopted the use of this method of illu-
miuation in the small way, and who gave a state-
ment of its advantages to the public, is Mr. COOK,
a manufacturer of metal toys, at Birmingham, :1
clear-headed prudent man, not apt to be dazzled
by a fanciful speculation, but governed in his
transactions by a simple balance of profit and loss.
There is a mziveté in his own account of the process
which will amuse as well as instruct the reader.

“ My apparatus is simply a small cast-iron pot,
“ of about eight gallons, with a cast-iron cover,
“ which 1 lute to it with sand. Into this pot I put
“ my coal. 1. pass the gas through water into the

u

G

A TREATISE 0N GAS-LIGHT. 89

gasoineter or reservoir, which holds about 400
gallons; and, by means of old gun-barrels, con-
vey it all round my shops. Now, from twenty
to twenty-ﬁve pounds of coal, I make, perhaps,
six hundred gallons* of gas; for, when my re-
servoir is full, we are forced to burn away the
overplus in waste, unless we have work to use
it as it is made: but, in general, we go on
making and using it, so that I cannot tell to ﬁfty
or a hundred gallons ;—-—and, in fact, a great
deal depends on the coals, some coals making
much more than others. These twenty-ﬁve
pounds of coal put into the retort, and say
twenty-ﬁve pounds more to heat the retort,
which is more than it does take one time with
another, but I am willing to say the utmost,
are worth four-pence per day. From this four-
pence, we burn eighteen or twenty lights during
the winter season.”

Thus are the candles which Mr. Coon used to

employ, and which cost him three shillings a day,

entirely superseded. But, besides his expence in

candles, oil and cotton for soldering used to cost
him full 30L a year; which is entirely saved, as he
now does all his soldering by the gas ﬂame only.

" A Wine gallon is equal to 281 cubic inches.
N

90 A TREATISE 0N GAS-LIGHT.

For “ in all trades in which the blow-pipe is used
“ with oil and cotton, or where charcoal is em-
“ ployed to produce a moderate heat, the gas
“ ﬂame will be found much superior, both as to
“ quickness and neatness in the work: the ﬂame
“ is sharper, and is constantly ready for use;
while, with oil and cotton, or charcoal, the
workman is always obliged to wait for his lamp
or coal getting up; that is, till it is sufﬁciently
on ﬁre to do his work. Thus, a great quantity
of oil is always burned away useless; but,
“ with the gas, the moment the stop-cock is
“ turned, the lamp is ready, and not a moment is
“ lost.” We must refer to Mr. Coon’s letter for
the details of expeuce, which he gives with faithful
minuteness, and always leanng to the side unfa-
vourable to the gas The result of the whole is,
that he saves 301. out of the 501. which his lights
formerly cost him : and when we consider that his
calculation allows the gas-lights to burn the whole
year, and the candles only twenty weeks, there
can be little doubt, that the savings in this case,
follow nearly the same proportion as in the former.
If the apparatus be erected even on a smaller
scale, “ the saving,” Mr. COOK assures us, “ will
“ still be considerable: for the poor man, who
“ lights only six candles, or uses one lamp, if

“ the apparatus is put up in the cheapest. way

A TREATISE 0N GAS-LIGHT. ‘ 91

“ possible, will ﬁnd it only cost him 101. or 121.
“ which he will nearly, if not quite, save the ﬁrst
“ year." ‘ ‘

Mr. ACKERMAN having, in this town, set the ex-
ample of lighting his establishment with gas, seve-
ral other individuals soon followed the attempt.
The following statement will shew, that this spe-
cies of light maybe made use of with the greatest
advantage, upon a still smaller scale, where no
great nicety with regard to the apparatus for pro-
curing gas is required. The following report I
have received from Messrs. LLOYD, of Queen-
street, Southwark, thimble manufacturers and
whitesmiths, who have used the gas-light for sol-
dering and other purposes these ﬁve years past. ‘

From 4 peeks or 1 bushel of coals,
weighing 691bs. for which we now
pay (1809) Is, we produce 4% pecks
of coke and % peck of coal not car-
bonised remains in the distilling pot,
which together with the coke weighs
58lbs. 6 oz. value at ls. per bushel 0 1 4
we procure Glbs. 4 oz. of tar, which

 

we use as pitch——it saves us ----- 0 l O

O 2 4

Deduct for coal ----- ' O 1 C

Proﬁt on coke and tar ---------- O I 4

92 'A TREATISE on GAS-LIGHT.

The gas yielded by the 4 peeks of coals.

in the pot, make 42 brilliant! lights,
which burn 7 hours. To keep 42
tallow candles which were formerly
used in the manufactory, burning for
the same time, required 7lbs. which
atls. per lb. cost ----------- 0 7 0

To this, add proﬁts on coke and tar O 1 4

Gained out of every bushel of coal 0 8 4

N

U

‘

n

{C

“ The gas-burners made use of in our manu-
factory produce jets of ﬂame, which in our bu-
siness, where much soldering with the blow—
pipe must be done, have a decided superiority
over Argand’s lamps. We are not nice concern-
ing the quality of the gas—a great part of it
is burned from the gasometer, without allowing
it to purify itself in the gasometer, because our
gasometer is not large enough to store up the
whole quantity of gas we want for use.”

(93)

DESCRIPTION
or THE

APPARATUS AND MACHINERY,

Now successfully employed

For Illuminating Streets, Houses, and Manafactories,

WITH

CA RBURETTED HYDROGEN,

0R

COAL-GAS.

BEFORE we proceed to give a description of the
gas—light machinery best calculated for illuminat-
ing streets, houses, and manufactories, we shall
exhibit a description of a portable apparatus for
exhibiting in the small way, the production, and
general nature of thisinew species of light. ,

To obtain carburetted hydrogen, or coal-gas,
from common pit-coal, and to apply it for the pur-
poses of illumination, the coal is introduced into
large iron cylinders, called retorts, to the aper-
tures of which iron pipes are adapted, terminating
in a vessel or vessels, destined to purify and col~
lect the gas. The retorts, charged with coals and
made air-tight, are placed upon the ﬁre, the ac—

 

1r; .

94 A TREATISE 0N GAS-LIGHT:

tion of which eXtricates the gazeous products from
the coals, together with an aqueous ammoniacal
vapour, and a tenacious bituminous ﬂuid, or tar,
&c. The liquid substances are conveyed into pro-
per Vessels, and the gazeous products‘are con-
ducted, by means of pipes, under the gasometer,
where the gas is again washed, and remains ready
for use. There are also other pipes leading from
the gasometer, which branch out into smaller ra-
miﬁcations, until they terminate at the ‘places
where the lights are wanted. The extremities of
the pipes have small apertures, out of which the
gas issues, and the streams of gas being lighted at
those apertures, burn with a clear and steady
ﬂame as long as the supply of- gas continues. All
the pipes which comes from the gasometer are
furnished at their extremities with stop-cocks to
regulate the admission of the gas. The burners
are formed in various ways, either a 'tube ending
with a simple oriﬁce, at which the gas issues in a
stream, and if once lighted will continue to burn
with the most steady and regular light imagin-
able, as long as the gas is supplied; or two
concentric tubes of brass or sheet iron, are
placed at a distance of a small fraction of an
Inch from each other, and closed at the bottom.
The gas which enters between these cylinders,
when lighted, forms an Argand lamp, which is

 

 

 

 

 

 

 

 

 

 

/r'//1/t‘//V/'///' ///r/‘// / 1’ ' H) " /',/lr/ ,'//u'u//.., '1, AWN/MC

A TREATISE 0N GAS-LIGHT. 95

supplied by an internal and external current of ,
air in the usual manner. Or the two concentric
tubes are closed at the top with a ring, having
small perforations, out of which the gas alone can
issue, thus forming small distinct streams of
light. =‘ " g
The gas apparatus, plate 2, will be found very
convenient for exhibiting, in the small way, the ge-
neral nature of this new art of illumination, whilst
at the same time it may serve to ascertain, at a
triﬂing expence, the comparative value of different
kinds of coals intended to be employed for the
production of this species of light, as well as other
occasional purposes connected with the gas-light
system of illumination. 5"
It consists of three distinct apparatus :—na1ne-
ly, a portable furnace, ﬁg. 1, plate 2, by means of
which the gas is prepared—ﬁg. 2, a puriﬁer or
’ condenser, which separates and puriﬁes the pro-
ducts obtained from the coal, so as to render the
gas ﬁt for the purpose of illumination—ﬁg. 3, a
gasometer, or reservoir for receiving and preserving
the puriﬁed stock of gas, and from which it may
be transferred and distributed as occasion may re-
quire. The following statement will explain more
fully the general nature of this portable chamber
apparatus: a, represents a cast iron retort, such
as is used for chemical operations .in the small

 

96 A TREATISE 0N. GAS-LIGHT.

way. This retort rests upon a tripod , of ham-
mered iron, placed upon the bars of the grate of
the chemical furnace. Into this retort the coals
are put for furnishing the gas. It is provided with
a solid iron stopper ground air-tight into the mouth
of the retort, and the stopper is secured in its
place by an iron wedge passing over it in the cen-
tre; by means of which the mouth of the retort
when charged with coal, is readily made air-tight,
and the stOpper may easily be removed by knock-
ing out the iron wedge. b, is a metal pipe which
conveys all the distillatory products from the re-
tort into the puriﬁer, ﬁg. 2. This tube is bent at
right angles at the extremity where it enters the
intermediate vessel, ﬁg. 2. The puriﬁer, ﬁg. 2, is
divided into three compartments marked c. (1.6.
The ﬁrst compartment is ﬁlled with water, and by
means of it an air-tight communication is estab-
lished with the retort which furnishes the gas.
The second compartment, d, contains a solution
of caustic pot-ash, composed of about :2 parts of
caustic pot-ash and 16 of water, or a mixture of
quick-lime and water, of the consistence of
very thin creann The object of this compartT
ment is to separate the non—inﬂammable gases and
other products evolved during the distillation of
the coal, from the carburetted hydrogen or coal-
gas, so as to render it ﬁt for use. The third com-

A TREATISI: ON GAS-LIGHT. 97

partment, e, is left empty to receive the tar, and
other liquid products. Into the ﬁrst compartment,
c, all the gazeous and liquid products are delivered ,,
as they become evolved during the distillation,
by means of the pipe I). The compartment, d, of
the puriﬁer, or alcali vessel, is fumished with a
wide perpendicular pipe, which serves to make an
air-tight communication with the retort, by allow-
ing the tube 6, to pass readily through it. From
the chamber, 0, the liquid and gazeous product;
pass to the tar-chamber, or compartment e, by
means of the descending pipe, f The tar and
other condensible substances are therefore depo-
‘sited at e, whilst the gazeous products alone as-
cend from the tar-chamber, e, by the pipe, g, and _
down again the pipe, h, (which is closed at the
top) into the compartment, d, of the vessel, or pu-
riﬁer, ﬁg. 2. The gas being thus made to pass
from the compartment, e, up into the pipe, g, and
down the pipe h, (which is closed at the top) intO'
the puriﬁer, d, is brought into contact with the li-
quor in that vessel, where it is opposed to a pres-
sure in proportion to the perpendicular height of
the column of liquid which it contains. The fun-
nel in the compartment, 0, is considerably higher
than the purifying apparatus, it therefore allows
the liquid which it contains, when pressed upon
by the gas, to ascend into it, without overﬂowing
0 V

98 A 'I‘REATISE ON GAS-LIGHT.

the apparatus, and to ascend again as the pressure
diminishes—i, is another wide-mouthed funnel, by
lneans‘of which the chamber, d, is ﬁlled with the al-
caline solution, or 'mixture of lime and water.
The carbonic acid gas and sulphuretted hydro-
gen, evolved during the distillation of the coal, are
thus made to combine with the alcali or lime, in
the compartment, (1, of the puriﬁer, forming car—
bonate and hydro-sulphuret of lime. The carbu-
re‘tted hydrogen, being left more or less pure, is
conveyed through the pipe, k, into the gasometer,
ﬁg. 3. The communication of the puriﬁer, ﬁg. 2,
with the gasometer, is made by means of the well-
known water-valve, I, placed so that the the com— .
municating tube, k, may be easily removed at
pleasure—m, is a cock for drawing off the tar, &c.
n, a gauge cock for ascertaining the height of the
liquid in the chamber d. The gasometer, ﬁg. 3,
the object of which is to store up the gas, consists
of two principal parts—namely, alarge interior
vessel designed to contain the gas, and an outer
cistern or vessel, of rather greater capacity, in
which the former is suspended, designed to con-
tain the water by which the gas is conﬁned. The
interior vessel which contains the gas is suspended
by chains or cords hung over pullies, to which
weights are attached, so as to nearly equipoise it.
o, is a pipe, which communicates with the water

1!

A TREATISE 0N GAS-LIGHT. 99

valve, 1, and by means of which the gas passes
from the puriﬁer, ﬁg. 2, into the gasometer. The
upper end of this pipe is covered, in the manner
of a hood, by a cylindrical vessel, p, open at bot-
tom, but partially immersed beneath the surface of
the. water contained in the outer cistern of the
gasometer, and perforated round near the lower
edge, with a number of small holes. The gas
displaces the water from this receiver, p, and es-
capes through the small holes, rising in bubbles
through the water, so as to expose a large surface
to, its action, that it may be properly washed, ‘
&c. After rising through the water the gas enters
the gasometer, which is suspended, to move‘up and,
down, by the chains, pullies, and balance-weights,
q. From the centre of the gasometer, a tube, 7',
descends, which includes a pipe, 3, ﬁxed perpen-
dicular from the bottom of the cistern. The ﬁxed
pipe, 7', forms a guide to keep the gasometer al-
ways perpendicular. t, is also an iron pipe made
fast in the centre of the inner vessel, and commu-
nicates with the upright tube, 3, in the outer ves-
sel. This contrivance' obliges the gas to pass into
the pipe t, whilst it also serves to keep the gasome-
ter steady when nearly out of the outer cistern.
When the operation commences, the gasometer
is sunk down nearly to a level with the surface of
the water in the outer cistern, and is consequently

100 A TREATISE 0N GAS-LIGHT.

filled with water; but as the gas enters, it rises
up to receive it. It is to be noted, that the ba-
lance weights, q q, should not be quite so heavy as
the gasometer, in order that some pressure may be
exerted, to force the gas out of the burners with a
proper jet. The gas which issues from the retort
enters the puriﬁer, as stated already, and ascends
the pipe 0, into the vessel, p, from which it dis-
places" the water, and passes out at the small
holes, as before described, rising through the wa-
ter into the gasometer, and raising it up: the gas
then passes away to the burners, u u. In this
manner the process proceeds until the whole of
the volatile products of the coal in the retort is
evaporated. The use of the gasometer is, to
equalize the emission of the gas which comes from
the retort more quickly at some time than others-
When this happens, the interior vessel rises up to
receive it, and when the stream from the retort di-
minishes, the weight of the gasometer expels its
contents. When the process is ﬁnished, the re-
tort is suﬂ‘ered to cool, and its ground stopper is
then removed, to replenish it with coal. The re-
sidue found in the retort is coke. v v, are cocks
to let off any liquid that may collect in the pipe, 0
or t; for if the smallest portion of liquid were to
obstruct the free passage of the gas to the burners,
the consequence would be, that the lights would

A rnnArrsa 0N GAS-LIGHT. 101

not burn steadily—they would, as it is called,
dance, or become extinguished. x, is the main
stop-cock which communicates with the burners
-—these, of course, may be placed as convenience
may require. zz, are two projecting parts in the
top of the gasometer; they are intended to receive
the hood, p, andthe upper extremity of the pipe, t.
so as to allow the gasometer to be wholly immers-
ed into the cistern. The wheels or pullies of the
gasometer have a groove to allow the links of the
chain to pass freely. ' ,

In this apparatus there is no provision made for
the unequal pressure which the gas suffers, accord-
ingly as the gasometer is more or less immersed in
water. It will be observed that, in this apparatus,
the weight of the interior vessel is constantly in-
creasing, in proportion as it ﬁlls with gas, and
rises out of the water, and consequently, if a con-
stant, uniform, counterpoising weight, equal only
to that of the gasometer in the ﬁrst moment of its
rise, be employed, the gas becomes gradually
more and more compressed by that part of the
weight of the gasometer which is not counter-
poised, and if its pressure or quantity be then esti-
mated by the bulk which it occupies, without
making allowance for the increasing pressure, a
material error must arise, and this, in the large
way, would give rise to insurmountable difﬁculties

102 A TREATISE ox GAS-LIGHT.

with regard to the regulation of the size of the
' ﬂames ; which could not be rendered uniform.

Suppose the cistern or exterior vessel ﬁlll of
water, and the gasometer partly ﬁlled with gas
and partly with water, it is evident that the lid
lance weight may be so adjusted, as to occasion
an exact equilibrium, so that the external air shall
not tend to enter into the gasometer, nor the gas
to escape from it; and in this case the water will
stand exactly at the same level both within the
gasometer and within the outer cistern. On the
contrary, if the balance—weights be diminished,
the gasometer will then press downwards from its
own gravity, and the water will stand lower in the
gasometer than it does in the cistern; in this case,
the included air or gas will suﬂ'er a degree of
compression above that experienced by, the exter-
nal air, exactly proportioned to the weight of a
column of water equal to the difference of the ex-
ternal and internal surfaces of the water.

To compensate for this increasing weight of the
gasometer, and render a scale of equal gradua-
tions accurate, some haveingeniously adopted the
plan of a spiral pulley'to the chain, which has the
effect of gradually avoiding the evil, but the best
way of accomplishing it will be stated presently.

PLATE 1, exhibits a perspective view of a gas-

A TREATISE ON GAS-LIGHT. 103

light apparatus)“ for lighting factories, or small
districts of houses. It consists of the following
parts : which may be considered separately.

F 10.1. The Retort Furnace, for distilling the
coals. It is built of brick-work. The bricks which
are exposed to the immediate action of the ﬁre,
are PVclciz lumps, or ﬁre—bricks; they are bedded
in clay, or ‘vVindsor loam.

1“ m. 2. The Tar Cistem, to collect the coal-tar,
and other condensible products obtained during
the distillation of the coals. It is a cast-iron hol-
low cylinder, closed at the top with a cast—iron co-
ver, which has a very small hole to allow the air
to escape as the liquid enters into the. vessel.

FIG. 3. The Lime Machine, for purifying the
crude coal—gas, and to render it ﬁt for use. The
construction of this machine will be explained in
plate v11. It is put togetherof cast iron plates.

FIG. 4. The Gasometer, for collecting and pre-
serving the puriﬁed gas, and for distributing and
applying it as occasion may require. It consists
of two principal parts—namely, a large interior
vessel, closed at the top and open at the bottom,
made of sheet-iron, designed to contain the gas, and
an outer cistern or vessel, of rather greater capa-

"‘Tliis apparatus was erected by Mr. CLEGG, and is new in action
at Mr. ACKERMAN’S establishment. in this metropolis.

104 A TREATISE 0N GAS-LIGHT.

city, constructed of cast-iron plates, in which the .
former vessel is suspended. The latter contains
the water by which the gas is conﬁned. The inte-
rior vessel which contains the gas is suspended by
chains hung over wheels or pullies, to which
weights are attached, so as to be just sufﬁcient to
balance the weight of the gasometer, all but a
small'diﬁ'erence, and allowing its slow descent in
the manner which is found as nearly adapted as
can be to the proper supply of the lamps. The
weight of the chains must be equal to the speciﬁc
gravity of the material of which the gasometer is
composed, so as to compensate accurately for the
quantity of water which the gasometer displaces,
or what is the same, it must be equal to the loss
of weight which the gasometer sustains, when im-
mersed in the water; and the counterpoise weight
must be equal (or nearly’so) to the absolute weight
of the gasameter.

The action of these different parts of the appara-
tus will be obvious from the following explanation:

A A, are two iron retorts, placed horizontally,
and side by side, in the furnace; the mouth of
the retorts where the coals are introduced, pro-
jects into an arched chamber, situated in front of
the furnace, as shewn in the drawing by the bro-
ken down brickwork. The object of suffering the
mouth of the retorts to project into a separate

A TREATISE 0N GAS—LIGHT. 105

chamber. is merely to discharge with convenience

the red hot coke from the retorts when the process

is at an end; the coke being suffered to fall to the ,
bottom of the chamber, where it cools, without?
becoming troublesome to the operator. It may be

removed from this ﬁre-safe chamber by the door re-

presented at the end view of the furnace.

When the operation commences, the inner vessel
of the gasometer, ﬁg. 4, is sunk down, to expel the
air which it contains to a level with the exterior
vessel, or outer cistern, of the gasometer; and
consequently, becomes ﬁlled with water. As the
distillation of the coal in the retorts proceeds, the
liquid and gazeous products evolved from the coals
are transmitted by means of the perpendicular sy-
phon‘pipes B B, into the horizontal pipe or main
condenser C, with which they are connected. The
liquid which is distilled, collects in the pipe, or
main condenser, c, Where it istretained until its
quantity has risen so high as to discharge itself into
the pipe D, which is connected with the upper part
of one of the extremities of the condenser, c. One
of the extremities of the pipes, B B, therefore be-
come immersed into the liquid contained in the
main condenser. or pipe 0, whilst the vaporous or
condensible ﬂuid, after having overcome the pres~
sure there opposed to it, is transported into the
pipe E, which, after passing in a serpentine direc~

r0

106 A TREATISE 0N GAS-LIGHT.

tion, E E, &c. through the exterior vessel or cistern
of the gasometer, terminates in the tar-vessel, ﬁg.
2. Thus the vaporous ﬂuids are condensed by
passing through the serpentine pipe, E E, &c., and
become deposited in the tar-cistern, ﬁg. 2; whilst
the non-condensible or gazeous products are made
to proceed by the pipe P, which branches off from
the pipe E, into the lime machine, ﬁg. 3. In this
apparatus the gas, as it is evolved from the coals,
comes into contact with slaked lime and water;
the object Of which is, to strip it of its sulphuretted
hydrogen and. carbonic acid gas with which it
always abounds, and to render it ﬁt for illumina-
tion. This being accomplished, the puriﬁed gas
is conducted away out of the lime machine by
. means of the pipe G, into the perpendicular pipe
H, which branches up through the bottom of the
gasometer cistern. The upper extremity of this
pipejs covered, in the manner of a hood, by a cy-
lindrical vessel, I, open at bottom, but partially im-
mersed beneath the surface of the water contained
in the outer cistern of the gasometer, it is also per-
forated round near the lower edge with a number
of small holes. The gas, as it passes out of the
pipe H, displaces the water from the receiver, 1,
and escapes through the small holes, and is thus
made to pass through the water in the cistern, in
which the hood of the pipe I, is partly immersed,

A “nurse 0N GAS-LIGHT. 107

so as to expose a large surface to its action, that it
may once more be washed, and deprived of all
the foreign gazeous products which might have
escaped the action of the lime, whilst it was agi-
tated with this substance in the lime machine, ﬁg.
3. After rising through the water in the gasome-
ter cistern. it enters into the gasometer, which then
ascends as the gas accumulates in‘it.

In this manner the process proceeds, until the
whole of the volatile products of the coal in the
retort are disengaged. The use of the gasometer
is, partly to equalize the evolution of the gas which
comes from the retort more quickly at some time
than others. When this happens, the vessel rises
up to receive it, and when the stream from the re-
tort diminishes, the weight of the gasometer expels
its contents, provided the main-cock be open.
When the process is ﬁnished, the retort is suffered
to cool, and its lid is then removed to replenish
it with coal. When the main stop-cock is then
opened, the gasometer descends, and the gas
passes from the gasometer through the pipe, K, to
the burners, or main pipe, which communicates
with the gas burners or lamps. L, is a wooden
tub or barrel, containing the mixture of lime and
water, for charging the lime machine; and into
which the contents of the barrel, L, may be con-
veyed _by the curved pipe, M, Without admitting

108 A TREATISE ON GAS-LIGHT.

common air. N N, is a water-pipe, to convey fresh
Water into the gasometer cistern occasionally; be-
cause it is essential that the water used for wash-
ing and purifying the gas should be changed for
fresh as soon as it becomes dirty; and unless this
is done, the gas will not be perfectly puriﬁed by
washing, but produce a disagreeable odour when
burnt; the same holds good with regard to the
lime machine, the contents of which should be re-
newed occasionally. This pipe also conveys the
necessary water into the barrel, L. '0, is a waste-
pipe, to convey the water as it becomes impreg-
nated with the impurities of the gas out of the
g-asometer cistern. P, is an agitator, to stir up the
contents of the lime machine occasionally. Q Q,
are two iron rods, which serve as stays to guide
the motion of the gasometer. R, is an index, con-
nected by means of a shaft and pulley with the
axis of one of the gasometer wheels. This index
is graduated to the capacity of the cubical con-
tents of the gasometer, so as to indicate, by the
rising and falling of the gasometer, its relative con-
tents of gas expressed in cubic feet. s, is the
waste pipe of the lime machine, to remove the in-
soluble parts of the lime. T, represents the iron
cover, or lid, which is turned on the lathe, and
ground air-tight, to close up the mouth of the re-
tort, so as to make readily an air-tight ﬁtting. U,

A TREATISE 0N eras-LIGHT. 109

is an iron wedge to secure the cover of the retort.
The left-hand retort in the design shows the'retort
closed up, and the cover, or lid of the mouth of it,
secured by means of the wedge, in its place, so as
to render the mouth of the retort perfectly air-
tight.

There is a safety valve attached to this gasome-
ter which could not be represented in the drawing;
and the object of which, is, to convey away any
portion of gas that might happen to be produced
by a careless operator, when the gasometer is full,
and which is thus prevented from accumulating in
the place where the gasometer is erected. It is
represented in the right hand corner of plate VII.
where ﬁg. 1 shows the edge of the gasometer; 2,
the surface of the water in the inside of the gaso-
meter; 3, the surface of the water in the outside of
the gasometer, or in the cistern ; 4, a pipe issuing
from the lower edge of the gasometer, and sur-
rounded at its upper extremity with a cup marked
5; 6, the waste-pipe, the mouth of which is im-
mersed in water. It is obvious that, when the
gasometer is full, if an additional quantity of gas
should be attempted to be put into it, it will be
transported by means of the pipe, 4, into the
waste-pipe, 6; the upper extremity of which
reaches out of the building, and there communi-
cates with the open air. _ I

110 A TREATISE 0N GAS-LIGHT.

PLATE V H Exhibits a perpendicular section of
a. gasJight apparatus, calculated for lighting
towns, or large districts of streets and houses.

FIG. 1.‘ The Retort Furnace. The retorts are
placed over each other in one or more rows; so
that a certain number of them may be heated by
separate ﬁre-places. A, A, shows two of the re;
torts placed horizontally above each other; B,
the ﬁre-place; c, the ﬂue which causes the ﬁre to
'circulate round the retorts so as to heat them
equally in every part; D, the opening of the ﬂue
where the ﬁre passes into the chimney; E, the
ash-pit; F, a chamber in front of the retort furs
. nace, into which the oriﬁce or mouth of the retorts
project; G, G, the doors of the chamber, to enable
the workmen to charge and discharge the retorts;
H, a funnel-shaped hole at the ﬂoor of the cham-
ber F, through which the red-hot coke as it is dis-
charged from the retorts passes into the arched
vault i; K, the syphon tube; L, the horizontal
condeiiser*—~the action of both of these pipes
have been already explained, p. 105; M,‘main

* The condenser in this apparatus is placed at right angles to the
row, or rows of retorts. It is furnished at one extremity with a par-
tition placed perpendicularly, and of a height equal to about one-
hnlf of the diameter of the condenser. The object of this partition
is to prevent the tar, 8w. deposited in it, to seal the pipes K K, and
not to discharge itself into the pipe M, till this has been ell‘ected. The
partition is seen in the drawing.

A TREATISE 0N GAS—LIGHT. ‘lll

pipe, which conveys the liquid substances from
the condenser, to the tar cistern, ﬁg. 3, and which
conducts also the gazeous products into the lime
machine, ﬁg. 2; N N, shows that part of the pipe
which is interposed between the tar cistern, ﬁg. 3.
and the condensing pipe M,———it passes in a 861'.
.pentine direction along the inner sides of the gas—
ometer cistern, and, like the so-called worm in a
distillatory apparatus, condenses the products
which escape in a vaporous state from the con-
denser L; 0, shows the place where the serpentine
pipe N N, passes again out of the gasometer cis-
tern, and its communication with the lime machine,
ﬁg. 2, and tar chamber, ﬁg. 3. The action of the

lime machine is as follows: The liquid products .

evolved from the coal, having been deposited in
the tar cistern, ﬁg. 3, by means of the serpentine,
pipe N, N, the gazeous products which accompany
it, are conveyed by means of the pipe P, which
branches out from the pipe o, into the interior re-
ceptacle of the lime machine marked Q, which
consists of a vessel open at the bottom, and closed
at the top, where it communicates with the pipe 0.
As the gas accumulates in the interior part Q, of
the lime machine, it is made to pass through the
liquid which it contains, namely, slaked lime and
water; and escapes through apertures made in
the horizontal partitions R, R, R, R, into the outer

112 A TREATISE 0N GAS-LIGHT.

vessel, s, of the lime machine and from thence it
is conducted away by the pipe T, T, T, into the ad-
ditional washing apparatus of the gasometer; ﬁg.
4, the construction of this apparatus, greatly re-
sembles the lime machine, ﬁg. 2, namely, v, is a
water-pipe, proceeding from a cistern U, placed 3
or 4 feet above the oriﬁce of the pipe v; T, T, is
the gas pipe covered with a hood, marked w, and
immersed in a small cistern, having horizontal per-
forated shelves, like those in the lime machine—
they ﬁt close to the hood. :The gas which enters
the hood W, meets with a shower of water deli-
vered by the pipe v. The gas, as it passes through
the holes in the horizontal partitions, is, therefore,
again washed and thoroughly puriﬁed from foreign
gases Which may have escaped the action of the
lime machine; Y, is a waste pipe, the lower ex-
tremity of which is sealed by being immersed in
water,—it serves to carry away the water delivered
by the pipe v, as it has been acted on by the gas.
The summary action of this gas apparatus is,
therefore, as ‘follows: The liquid products ob-
tained from the coal during the distillation are
ﬁrst deposited in the main condenser L, by means
of the pipe K, and from whence they cannot es—
cape until a quantity of tar has accumulated in it
to a certain height, and by this means, one of the
extremities of the pipes K, K, becomes immersed

A TREATISE 0N GAS-LIGHT. 113

and hermetically sealed by the liquid which the
condenser L, contains. The liquid products, after
havmg accumulated to a certain height in the
condenser, overﬂow the perpendicular portion
which it contains, and discharge themselves into
the pipe M, from whence they are transported into
the tar cistern, ﬁg. 3, by means of the system of
pipes N, N, o, whilst the gazeous products are
made to pass by means of the branch pipe P,
into the lime machine, ﬁg. 2. From‘this part of
the apparatus the gas passes through the pipe
T, T, T, into the additional or smaller washing ap-
paratus placed upon a tressel in the cistern of the
gasometer, where it is again exposed a second
time to the action of a current of fresh water;
and from this vessel the gas ascends into the gas-
ometer. The gasometer is furnished with a pipe,
A, closed at the top, and ﬁxed in one corner of the
gasometer, but open at the bottom; it includes
another pipe, marked B, which communicates with
the main pipe leading to the burners, or place
where the gas is wanted. The pipe A, which slides
over the pipe B, is perfdrated at the top, the gas
passes through these perforations, and is thus
made to enter into the pipe B, and disposed of as
mentioned. 0, c, is a tube of safety adapted to the
gasometer; its lower extremity remains sealed by
the water in the cistern so long as the gasometer
Q

4‘1 'b

114 A TREATISE 0N GAS—LIGHT.

is not overcharged , with gas ; but, if more gas
should be made to enter the gasometer than it is
destined to receive, this pipe then delivers the gas
into the funnel-shaped tube, D, which reaches
through the roof of the gasometer house, and thus
the superﬂuous quantity of gas is conveyed away
into the open air.

The cylindrical vessel, F, of ﬁg. 3, surrounding
the oriﬁce of the pipe 0, which delivers the tar into
the tar cistern, ﬁg 3, serves to keep this pipe con-
stantly immersed into a portion of tar, so that the
contents of the cistern may be drawn off by the cock
without admiting air into any part of the apparatus.
The tar cistern has a small hole at the top, to allow '
the air which it encloses to escape, as it becomes ﬁll-
ed with tar and ammoniacal liquor. The main con-
denser L, is placed, as shown in the drawing, higher
than the level of the water in the gasometer cistern,
to allow a free descent of the distillatory liquids as
they pass from this vessel along into the pipes M,
N, 0, &c. The cistern of the gasometer, as well
as the lime machine, and tar cistern, are construct-
ed of cast-iron plates, bolted and cemented toge-
ther With iron cement. The gasometer is made
of sheet iron plates rivetted together-we, E, are
two iron stays—e, G, are friction wheels.

A TREATISE ON e'Asuueu'r. ll5

METIIOD of Correcting the relative pressure of
the Gasometer, so as to cause the gas which it
contains to be ung'formlg/ of an equal densityf“ ‘

WE have mentioned already that the pressure
of the gas in the gasometer should be invariable,
for it is obvious that the weight of the gasometer
is constantly increasing, in proportion as it ﬁlls
with gas, and rises out of the water—see page
103. To render its pressure uniform, we ﬁrst
take the absolute weight of that part of the gaso—
meter which becomes immersed in the water, and
knowing the specgﬁc weight of the substance of
which it is composed, we divide its absolute
weight by the speciﬁc weight of the substance of
which it is composed; and this being done, we
make part of the chain, (measured at right angles
from the axis of the wheels over which it passes
downwards towards the top of the gasometer,)
which is equal to the length of that part of the
gasometer which becomes immersed in water,
equal in weight to the speciﬁc gravity of the sub-
stance of which the gasometer is composed. For
example, let us suppose that the part of the gas-

, " For this elegant contﬁvance we are also indebted to Mr. Cums.

116 A TREATISE ON GAS-LIGHT.

ometer which becomes immersed in water weighs
861155. and that it is composed of sheet iron, the
speciﬁc gravity of which, in round numbers, we
will take to be 7. It is then evident, that the part
of the chain of the gasometer measured down-
ward Ifrom the axis of the wheel over which it
passes, and which is equal in length to the height
of the gasometer, must be loaded with a weight
of, or must itself weigh 123le. for this would
be the weight of the water displaced by the gas-
ometer; or let us suppose the gasometer to be
made of sheet copper, the speciﬁc weight of
which (omitting decimals) is 8; and that the ab-
, solute weight of the gasometer is 1792165. then
the chain of the gasometer equal in length to the
height of the gasometer, immersed into the water
must weigh 224 lbs. for this would be the weight
of the quantity of water which the gasometer dis-
places. This'being accomplished, by then adding
or diminishing the absolute or balance weight of
the gasometer, any desired uniform pressure may
be effected, and the same bulk of gas will always
be of_ the same speciﬁc gravity

(117)

DIRECTIONS

TO IVORKZIIEN

ATTENDING THE

GAS-LIGHT APPARATUS*.

 

PARTICULAR care must be taken to make the
joints of the mouth-pieces of the retorts perfectly
air tight, which may be done in the following
manner: Take some common clay, dry, pulverize,
and sift it, then add as much water as will make
it into the consistency of treacle; make the mouth—
piece and the lid of the retort clean,’ lay this
luting thinly over the turned part of the lid, press
the lid so luted gently to the mouth—piece, and
then secure it moderately, by means of the iron
wedge: if the workman observes this rule, he
will never fail to make good joints; but if, on the
other hand, the operator is careless and neglects
to remove the old luting, &c. from the turned or

* Copied from a. printed direction drawn up by Mr. Clegg, for the
trio of workmen.

118 A TREATXSE 0N GAS-LIGHT.

smooth part of the mouth of the retort, and there-
by cause a bad joint, the consequence will be the
loss of a considerable quantity of gas, and a very
disagreeable smell and smoke.

The bridge or row of bricks of the ﬂue c, of
the retorts, should never be made hotter than a
bright red, which may be regulated by the door
of the ash-pit being kept close shut when the ﬁre
is getting too hot. If the operator neglects this,
and suffers the ﬁre-bricks to arrive at a bright
white heat, the retorts will soon be destroyed, and
bad gas be produced.

The gasometer should be well examined, at least i
once a week, to see if it leaks, by the following
method, viz. Let the main stop-cock be shut, then
make amark on the gasometer at the water’s edge,
when it is full or nearly of gas, there being no gas
coming from the retorts at the time, and if the
mark sinks in the water, the gasometer leaks; to
ﬁnd out the place, walk slowly round it, and you
may perceive the leak by the smell, apply a lighted
candle to the part suspected, and if there be gas
issuing from it, it will take ﬁre, and perhaps ap-
pear like a small blue ﬂame—blow it out, and
mark the place: thus proceed round the gasome—
ter till you have found all the p aces ; if you per-
ceive a smell, and yet cannot produce a ﬂame in
the part suspected, take a brush with a little thin

A TREATISE ON GAs—LIGHT 119

white-lead paint, and lay it on the part where you
think the leak- is, and, if it be there, the gas which
escapes from the leak, will immediately turn the
paint brown; After the sides of the gasometer
have been well examined, and secured by dipping
a piece of cloth about the size of a shilling, into
some melted pitch, tempered with a little bees‘
wax and tar, apply the cloth whilst hot to the
place with the end of your ﬁnger, rubbing it till
it is quite cold; next examine the top of the gas-
ometer in the same manner,-when it‘ is about two
feet high in the cistern, it will then be better to
get at. The water in the cistern should'always
be kept Within three or four inches of the top, if
suﬂ'ered to sink much lower without replenishing,
the gas will not pass through a sufﬁcient quantity
of water, and oily particles will be apt to con-
dense in the pipes, to their great detriment.

The only thing to be observed in the place
lighted, is, that the lamps and pipes are not suf-
fered to be touched on any pretence whatever;
but by the person entrusted with their care.
When a lamp is not wanted, it must be completely
shut off from the pipe which supplies it, by a stop-
cock provided for the purpose, and not opened
again but when a ﬂame is held over it; not a
lighted candle, as the tallow is liable to drop into
the lamps; lighted paper is better.

120 A TREATISE ON GAS-LIGHT.

PLATE VI—FIG. ]. Exhibits a design of the
gasometer flaming or skeleton, which serves to
give stability and strength to the gasometer. It
consists of wooden frame work, marked A, A, A,
interlaced with iron rods, B, B, B, &c. The whole
framing is so disposed that it will ﬂoat in the cis-
tern horizontally, and therefore keep the gasome-
ter perfectly steady and level with the surface of
the water.

‘The rest 'of the sketches of tlns plate represent
various kinds of gas pipes employed as mains for
conveying the gas, and the methods of connecting
them.

FIG. 2. Represents a longitudinal section of a
Spigot and Faucet Pipe. These kinds of pipes
are applicable in most cases as mains for convey-
ing gas. A, is called the spigot, and B, the faucet.
They are joined together, and made air-tight, by
iron cement, the composition of which is as fol—
lows :

Take two ounces ofsa] ammoniac, one ounce of
ﬂowers of sulphur, and sixteen ounces of cast—
iron ﬁlings or borings. Mix all well together, by
rubbing then] in a mortar, and keep the powder
dry.

When the cement is wanted for use, take one
part of the above powder, and twenty parts of
clean iron borings or ﬁlings, and blend them inti-

A TREATISE ON GAS—LIGHT. 1:21

mately, by grinding them in a mortar. Wet the
compound with water, and when brought to a con-
venient consistence, apply it to the joints with a
wooden or blunt iron spatula.

By a play of afﬁnities, which those who are at
all acquainted with chemistry, will be at no loss to
comprehend, a degree of action and re-action takes
place among the ingredients, and between them
and the iron surfaces, which at last causes the
whole to unite as one mass. In fact, after a time,
the mixture and the surfaces of the ﬂanches be-
come a species of pyrites (holding a very large
preportion of iron,) all the parts of which cohere
strongly together.

The inner parts of the faucet ought to be no
larger in diameter than just to ﬁt the spigot. This
supports the pipe, independently of the cement,
and prevents the risk of hurting the joint from any
external stress. The inner faucet is commonly
made about 2% inches deep, and has the spigot in-
serted 1% inch into it. The practice of some
workmen, is to make the outer faucet, or that
which contains the cement, six inches deep, for all
pipes above six inches diameter; and to make the
faucets of all pipes below six inches, the same
depth as the diameter of the pipes. It is usual
to make the space for the cement, all round the
spigot, from 1 to 1% inch; that width is required,

R.

a;

122 A TREATISE 0N GAS-LIGHT.

in order that the cement maybe ﬁrmly driven into
the joint. When the space is very narrow, this
cannot be done. On the other hand, when too
wide, there is a waste of cement, and a risk of
injury from unequal expansion.

FIG. 3. Exhibits a proﬁle view of these kinds of
pipes when joined together. The spigot and faucet
pipes are liable to burst from the great expansion
of the spigot, and the risk of this accident is in-
creased by increasing the space between the spigot
and faucet, which requires to be ﬁlled with cement.

FIG. 4. Represents a longitudinal section of
two ﬂanch pipes, and the modes of connecting
them. A and B, show the parts of the pipes :,
and c and D, the ﬂanches. These pipes are also
joined together, and rendered air-tight, by interpo—
sing between the ﬂanches rope-yarn, hemp, or
some other pliable material, and iron cement, and
then screwing up the faces of them by means of
the bolts and screw nuts.

FIG. 5. Proﬁle view of the same kind of pipes
connected together. A and B, the pipes; c and D,
the ﬂanches; E and F, the bolts.

FIG. 6. Represents the method of joining spigot
and faucet pipes when they are to have a turn or
angle. This method is convenient when the place
where the turn required to be made is previously
known, and the pipes cast accordingly.

A TREATISE ON GAS-LIGHT. 123

FIG. 7. Exhibits the method of connecting
spigot and faucet pipes when they have a round
turn. A and B, the junctures of the pipes.

FIG. 8. Represents a longitudinal section of the
mode of joining pipes by means of what is called
a thimble joint. The junctures of the pipes to
be connected, are made air tight, as mentioned
already, by iron cement. A, the thimble or small
cylinder, with projecting edges, which unites the
pipes B, c.

F 1G. 9. A thimble joint made in two parts,
which is sometimes convenient to join pipes. The
parts are joined together by screw bolts, and nuts,
in the usual manner. - .'

FIG. 10. Section of the same.

FIG. 11. Represents a proﬁle view of What is
called the saddle joint. It Is employed for taking
off a branch-pipe. The branch has a piece A B,
formed on its end, and ﬁts round one-half of the
outside of the pipe from which it is to proceed, c,
is called the saddle, which ﬁts round the other
half of the pipe. The parts are secured together
by screw bolts, and iron cement. By this method
a branch may be formed on any part of a gas-
pipe, by cutting a hole there, and applying the
branch to that place. Where there is much risk
of the inequality of expansion, the joints at cer-
tain places, should be secured by a soft stufﬁng

.124 A TREATISE ON GAS-LIGHT.

of hemp and tallow ; but in most Cases the joints
may be made with iron cement. Lead is fre-
quently used for making the joints of gas pipes
instead of iron cement, though cheaper and more
easy of repair. The galvanic action which takes
place between the lead and iron, soon renders
the joints leaky, and the danger is increased by
the unequal expansion of the two metals.

FIG. 12. Section of the saddle-joint.

Before the gas is suffered to enter into the pipe,
they should be proved to be sound, by the usual
process of forcing water into them. The pipes

rving as mains, are placed perfectly solid, so that
tiey cannot give way; their course should he rec-
tilinear, having a descent of about 1 inch i119 or
10 feet, to allow the water of condensation which
may be deposited from the gas by a change of
temperature to collect readily at the lowermost
part.

FIG. 18. Shows a reservoir for collecting the
water of condensation which might accumulate
in the pipes. It consists of a receptacle, A, in
which the water may pass; B, a branch-pipe
closed at the top, by means of which the water
may be removed, by drawing it out with a syringe.
This receptacle is placed in those situations
where pipes incline towards each other.

(125)

PHILOSOPHY

OF

THE PRODUCTION OF COAL GAS:

ITS CHEMICAL CONSTITUTION,
GENERAL HABITUDES, AND PRACTICAL REMARKS
CONCERNING THE BEST

' METHODS OF OBTAINING IT.

 

‘VITH regard to the philosophy of coal-gas, its
productions as stated prove that pit—coal contains
solid hydrogen, carbon, and oxigen. IVhen the
intensity of the heat, to which the coal is exposed,
has reached a certain degree, a part of the carbon
unites with part of the oxigen and produces car-
bonic acid, which by means of caloric, is melted
into the gazeous state and forms carbonic acid
gas; at the same time, part of the hydrogen of
the coal combines with another portion of carbon
and caloric, and forms the carburetted hydrogen
gas, “ hich varies considerably in its constitution, ,
according to the circumstances under which it is
produced: a portion of oleﬁant gas, carbonic oxid,

126 A ’I‘REATISE ON GAS-LIGHT.

hydrogen, and sulphuretted hydrogen, is also
produced during the process. The quantities of
these products vary according to the nature of the
coal employed in the process.

Pit-coal is not the only substance which af-
fords carburetted hydrogen; this gazeous ﬂuid
may be obtained in a great variety of ways, and
with very considerable differences in speciﬁc
gravity and proportion of ingredients.

It is found plentifully native or ready formed
on the surface of stagnant waters, marshes, wet
ditches, &c. through which, if examined closely,
large bubbles will be seen to rise in hot weather,
and may be increased at pleasure by stirring the
bottom or mud with a stick.

In close still evenings if a lighted candle is held
over the surface, ﬂashes of blue lambent 'ﬂame
may sometimes be perceived spreading to a consi-
derable distance. All that is not fabulous con-
cerning the z'gnis fatuns is probably derived from
this source. This Species of gas is termed for dis-
tinction the carburetted hydrogen of marshes. In
the purest form in which it can be collected it is
mixed with about 20 per cent. of azot or nitrogen.

To procure the gas for the purpose of philoso-
phical amusement, ﬁll a wide-mouthed bottle with
the water of the ditch, and keep it inverted there-
in with a large funnel in its neck, then with a stick

A TREATISE 0N GAS-LIGHT. 127

stir the mud at the bottom just under the funnel,
so as to cause the bubbles of air which rise from
the mud to enter into the bottle; when by thus
stirring the mud in various places, the air may be
catched in the bottle.

Carburetted hydrogen gas is also given out very
- abundantly by all kinds of vegetable matter, when
subjected to a scorching heat sufﬁcient to decom-
pose them. When heated in close vessels much
more gas is obtained than when burnt in the open
air. If moistened charcoal be put into an earthen
retort and heat be applied till the retort becomes
ignited, gas will be evolved, consisting partly of
carbonic acid, and partly of carburettedhydrogen.
A gas of similar properties is obtained by causing
steam to pass through a tube ﬁlled with red hot
charcoal ; by passing spirit of wine, or camphor,
through red hot tubes; by distilling oils, wood,
bones, wax and tallow, or any animal or vegetable
body whatever.

Indeed it would be endless to enumerate the va-
rious sources of "this gazeous ﬂuid. A most cu—
rious variety of carburetted drogen gas has been
discovered by the associated Dutch chemists
(VAN DIEMAN, TROOSTWYCK, and others) which
is procured from ether or alcohol, and has the re-
markable property of generating a heavy oil when
in contact with chlorine gas. Hence it has been

128 A TREATISE 0N GAS-LIGHT.

termed oily carburettedhydrogen orolyiﬁant gas-—
it consists of carburetted hidrOgen, supersaturated
With carbon. The oil generated is heavier than
water, whitish, and semi-transparent. By keeping,
it becomes yellow and limpid ; its smell is highly
fragrant and'penetrating—its taste somewhat sweet
—it is partly soluble in water, imparting to it, its
.peculiar smell. A portion of this gas always ac-
companies the common carburetted hydrogen ob-
tained from coal, and those sorts of coal that
afford the largest quantity of it are best suited for
the production of gas-light.

The nature of carburetted hydrogen obtained
from coal varies considerably according to the con-
ditions under which it is obtained. The ﬁrst part
is always much heavier than the last, though still
lighter than common air, and holds in solution a
portion of oil, for on standing for some time over
water it becomes lighter, and is found to require
less oxygen for saturation than before. The oil
which it held suspended, then becomes precipi-
tated. The average speciﬁc gravity of the ﬁrst and
last gas mixed, which may be taken as an average
of the whole speciﬁc gravity is to that of common
air as 2 to 3—1121b. of common cannel coal pro-
duce at its minimum, from 350 to 360 cubic feet
of carburetted hydrogen gas; but the same quan-
tity 0f the best Newcastle coal, that is to say, such

A TREATISE ON GAS-LIGHT. 129

as coke, which, when laid on the ﬁre readily under-
goes a kind of semi-fusion, and sends out brilliant
streams of ﬂame, produces upon an average from
300 to 360 cubic feet of this gazeous ﬂuid, besides
a large portion of sulphuretted hydrogen, carbonic
oxid, and carbonic acid. Half a cubic foot of
this carburetted hydrogen, fresh prepared, that is
to say, holding in solution or suspension, a portion
of the essential oil, which is generated during the
evolution of the gas, is equal in illuminating power
to from 170 to 180 grains of tallow, (being the
quantity consumed by a candle six to the pound
in one hour.) Now, one pound avoirdupoise is
equal to 7000 grains, and consequently one pound
of candles of six in the pound, burning one at a
time in succession, would last (if we take 175
grains of tallow to be consumed in an hour)
’2—3:—=40 hours. To produce the same light we must
burn one half of a cubic foot of coal-gas per hour;
therefore, one-half multiplied by forty hours is
equal to twenty cubic feet of gas in 40 hours, con-
sequently equal to one pound of candles, six to
the pound, provided they were burnt one after an-
other. One hundred and twelve pounds of cannel
coal, produce, at its minimum, three hundred and
ﬁfty cubic feet of gas; and are equal to three
hundred and ﬁfty, divided by twenty, which last
is equivalent to one pound of tallow, making one
s

130 A TREATISE 0N GAS-LIGHT.

hundred and twelve pounds of cannel coal, equal
to $=17% lbs. of tallow. Further, one hundred
and twelve pounds of cannel coal, divided by se-
venteen and a half of tallow make six and four;
tenths of cannel-coal, equal to one pound of tallow.

With regard to Newcastle coals,~* it may be
stated that one chaldron of VVall’s-End coal may
be made to produce in the large way, upwards of
11,000 cubic feet of crude gas; which, when pro-
perly puriﬁed, diminishes to nearly 10,000 cubic
feet.

The production of carburetted hydrogen, both
with regard to quantity and quality from the same
kind of coal, depends much upon the degree of
temperature employed in the distillatory process.
If the tar and oil produced during the evolution of
the gas in its nascent state, be made to come in
contact with the sides of the red hot retorts, or if
it be made to pass through an iron cylinder or
other vessel heated red hot, a large portion be-
comes decomposed into carburetted hydrogen gas
and oleﬁant gas, and thus a much larger quantity of
gas is produced than would be obtained without
such precaution, from the same quantity of coal.T

* One chaldron of Newcastle coal weighs from 2850 to upwards
of 29781b.
1- 0110 pound of coal—tar produces 15 cubic feet of carburetted

hydrogen, abounding in oleﬁant gas.

A TREATISE 0N GAS-LIGHT. 131

The dlstillation of ' the coal (if gas be the chief
object) should therefore not be carried on too ra-
pidly. Most of the retorts used in the large way,
are calculated for containing about one hundred
weight of coal, and in general, when . previously
heated, produce from two and one-half to three
cubic feet of gas, in four hours for each pound
of coal they contain; but when the layer of coals
in them does not exceed four inches in depth,
three and one-half to four feet of gas may be ob-
tained in the same time.

The retorts best calculated for large gas-light
’ works are seven or eight feet long (Without the
mouth-piece) and twelve inches in diameter, ta-
pering down to ten inches—if they are larger the
coal which they contain cannot be heated pro-
perly. The advantages that may be derived from
the circumstances before stated, are of greater
value in the gas-light manufactory than is often
imagined, and the quantity as well as the quality
of the gas is very much inﬂuenced by such cir-
cumstances. If coal be distilled with a very low
red heat, scarcely observable by day-light, the gas
produced gives a feeble light—~if the temperature
be increased so that the distillatory vessel is of
a dull redness, the light is more brilliant and of
a better colour—if a bright or cherry-red heat be
employed the gas produced, burns with a brilliant

132 A TREATISE 0N GAS—LIGHT.

white ﬂame, and if the heat be increased so far
that the retort ”is almost white hot, and conse-
quently in danger of melting, the gas given out,
has little illuminating power, and burns With a
clear blueish ﬂame“; or if the coal abounds in
pyrites or sulphuret of iron, as is sometimes the
case with Newcastle coal, a large quantity of sul—
phuretted hydrogen is likewise evolved, which
although it increases the illuminating power of
the coal—gas, has the capital disadvantage, of pro-
ducing an intolerable suffocating odour, when the
gas is burnt which is particularly perceptible in
low rooms illuminated with such gas.

These observations also apply to the distillation
of tar, which when distilled either in a vaporous
or nascent state, during its ﬁrst production from
coal in the ordinary process, or if it be submitted
to a second distillation, mingled with a fresh por—
tion of pit—coal, a practice usually had recourse
to when this product cannot be disposed of more
advantageously. The best depth of coal in the
retort for procuring excellent gas, and at the same
time for yielding the greatest quantity from the
same weight in the shortest possible time, is about
six inches.

The brightness of the coal—gas ﬂame is rather

‘ It is chieﬂy a mixture \ f carbonic oxid, and hydrogen gas.

A TREATISE 0N GAS-LIGHT. 133

diminished when the gas has been long kept over
water, and hence, for illumination, it should be
used as soon as prepared, but of course properly
puriﬁed.

The quantity of gas taken up by Water is af-
fected by temperature, because the temperature ‘
increases its elasticity ; the quantity of gas ab-
sorbed, diminishes as the temperature increases,
and increases as the temperature diminishes.
,5- part of its own bulk of pure coal-gas is ab-
sorbed by the water over which it is conﬁned in
the gasometer.

The chemical constitution of this gazeous ﬂuid
is best ascertained by burning it in a vessel of oxy-
gen gas, over lime—water in a pneumatic reservoir,
by means of a bladder and bent brass pipe. Two
products are then obtained, viz. water and carbo-
nic acid. That water is produced may be shown
by burning a very small stream of the gas in a
long funnel shaped tube open at both ends. The
formation of carbonic acid is evinced, by the co-
pious precipitation of the lime—water in the forego-
ing experiment.

If carburetted hydrogen be mixed with a sufﬁ-
cient quantity of oxygen gas or common air and
ﬁred by the electric spark, or by any other method,
an explosion takes place more or less violent, ac-
cording to the quantity of carbonaceous matter con

134 A TREATISE ON GAS-LIGHT.

densed in the hydrocarbonat; and the remaining
gas consists of carbonic acid, together with any
unconsumed gas or excess of oxygen, whilst the
water condenses in drops on the sides of the ves-
sel. A few cubic inches of the mixed airs is as
much as can be conveniently managed at a single
explosion; and when any portion of oleﬁant gas
is present, even this quantity will endanger very
thick glass jars. A very vivid red ﬂame appears
at the moment of the explosion, and a great en—
largement takes place in an instant, after which
the bulk is suddenly reduced to much less than
the original quantity. When the carbonic acid is
absorbed by lime—water, if the gasses have been
properly proportioned, no gazeous residue is left,
except accidental impurities. Though carburetted
hydrogen gas is sometimes naturally produced in
coal mines, and occasionally-mixes with common
air, producing dreadful explosions, yet when coal
gas is mixed with common air, as it is obtained in
the large way in the gas—light nmnut‘actories, does
not explode unless the gas be to the air as 1 to 10
nearly. Such are the leading chemical habitudes
of this gazeous product. The varieties of carbu-
retted hydrogen gas all agree in being inﬂamma-
ble; but they possess this property in various
degrees, as is evinced by the variable brightness
of the ﬂame which they yield when set on ﬁre.

A TREATISE 0N GAS-LIGHT. 135

“ Messrs. SOBOLEWSKY and HORRER,’ of St.
Petersburgh, have employed wood for the purpose
of producing carburetted hydrogen gas. The py-
roligneous acid obtained in this operation, when
freed from the empyreumatic oil with which it is
mixed becomes acetous acid, and is applicable to all
the uses of vinegar. A cubic cord of wood equal
to 2.133 French metres (a metre being rather more
than an English yard), yields 255 Paris pounds of
charcoal, and 70 buckets of acid. The latter
gives 30 pounds of tar, after the extraction of it
50 buckets of good vinegar remain. The same
quantity of wood furnishes 50,000 cubic feet of
gas, sufﬁcient for the supply of 4000 lamps for
ﬁve hours.””'

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(137)

PART III.

 

UTILITY

OF THE

GAS-LIGHT ILLUMINATION,

WITH REGARD TO

PUBLIC AND PRIVATE ECONOMY

FROM what has been stated in the preceding
pages it becomes obvious, that a substance yield-
ing an artiﬁcial light may be obtained from com-
mon coal in immense quantities. The attempt to
derive advantage from so valuable a discovery is
surely no idle speculation. Let us therefore now
consider to what objects of public and private uti-
lity this mode of procuring light may be applied
with effect. It is obvious that coal—gas may be
preserved in a reservoir for any length of time, and
that it may be conveyed by means of tubes to any
distance, ﬂowing equably and regularly like water.
Those, indeed, who have not seen the contrivance,
T

138 A TREATISE‘ 0N GAS-LIGHT.

will ﬁnd it difﬁcult to imagine with what ease it is
managed. The gas may be distributed through
an inﬁnity 0f ramiﬁcations of tubes with the ut-
most facility. Near the termination of each of
the tubes through which it ﬂows, it is conﬁned by
a valve or stop-cock, upon turning which, when
required to be lighted, it ﬂows out in an equable
stream and ascends by its Speciﬁc levity. There
is nothing to indicate its presence; no noise at the
opening of the stop-cock or valve—no disturbance
in the transparency of the atmosphere—it instantly
bursts on the approach of a lighted taper, into a
' brilliant, noiseless, steady, and beautiful ﬂame.
Its purity is attested by its not blacking or soilng
in the least degree the metallic oriﬁce from which
it issues, nor even a sheet of white paper, or po-
lished surface brought in contact with it. There
is no escape ‘of combustible matter unconsumed,
which is so great a nuisance in all our common
lights. The products of the combustion are water
and carbonic acid gas*. The accurate and ele-
gant experiments of Dr. W. HENRY have shewn
in the most satisfactory manner, that considerably

in The water (which passes of in imperceptible vapour) is gene.
rated by past of the oxygen of the air uniting with part of the hydro-
gen, which forms the great bulk of the coal-gas : and the carbonic acid
gas is produced by the union of another portion of the oxygen uniting
with the smaller portion of carbon, which is the other component part
of the coal—gas.

A. TREATISE ON' 'lAS-LIGHT. 139

less carbonic acid is produced by the ﬂame of
coal gas, than by that of oil, tallow, or wax,*
which sufﬁciently refutes the absurd notions that
have been circulated respecting the pernicious ef—
fects of gas-lights. But if the gas from Newcas-
tle coal is badly prepared, or not deprived of the
portion of sulphuretted hydrogen, which it usually
contains, it then emits ﬁery sparks and produces
a portion of sulphureous acid by virtue of the
union of the oxygen of the air with the sulphur
dissolved in the gas, the consequence of which is,
a suffocating odour, which is particularly observa-
ble in the higher stratum of the air of apartments
in which the gas is burnt. Such gas likewise tar-
nishes all metallic bodies—it discolours the paint-

" 100 Cubic inches of carburetted hydrogen from coal, require for
burning 220 cubic inches of oxygen and produce 100 cubic inches of
carbonic acid—100 cubic inches of the same gas obtained from wax,
require for burning 280 cubic inches of oxygen and produce 137 cubic
inches of carbonic acid—-100 cubic inches of the same gas procured
from lamp-oil, require 190 cubic inches of oxygen for burning, and
produce 124 cubic inches of carbonic acid.

The following lines relating to the salubrity of the gas-light illumi-
nation are cOpied from Mr. Lee’s evidence in the House of Commons,
when examined on that subject.

Question—“ Is the health of your manufacturers at all affected by
the use of gas? Answer--Not in the least, or I would not have
adopted it. I believe I explained to the Committee, that I used the
gas-lights in my own house ﬁrst.”

Q. “ You have not seen the smallest alteration in the health of your
workmen ? A. Not in the least, for bad I seen it, it would have been a I
fatal objection to it.”

Q. “ And you say the same in regard to the use of the gas-lights in
your own family? A. Certainly I do.”

140 A TREATISE 0N GAS-LIGHT.

ings effected with metallic oxids, and always pro-
duces a suffocating odour very noxious to health.
It is freed from the sulphuretted hydrogen and
may be rendered ﬁt for illumination by passing it
repeatedly through very dilute solutions of sub—
acetate of lead, green sulphate of iron, quicklime
and water, or hyper-oxymuriate of lime.

As to the brilliancy of the ﬂame, an appeal may
be made to every one who has witnessed the gas—
light illumination, whether it be not superior to the
best wax candle-light, or the light of Argand’s
lamps.

It may be described as a rich compact ﬂame,
burning with a white and agreeable light. It is
also perfectly steady, when the ﬂame is limited to
a moderate size: in large masses, it is subject to
that undulation which is common to it, with all
ﬂames of certain dimensions, and is caused by
the agitation of the surrounding atmosphere. The
gas ﬂame is entirely free from smell. The coal-gas
itself certainly has a disagreeable foetid odour be-
fore it is burnt, so has the vapour of wax, oil, and
tallow, as it comes from a lamp or candle~ newly
blown out. This concession proves nothing
against the ﬂame of gas which is perfectly ino-
dorous, a white handkerchief, passed repeatedly
through it, and applied to the nose, excites no
odour. '7 i. l ,_

A 'IZREATISE ON GAS-LIGHT. 141

Another peculiar advantage of the gas ﬂame
is, that it may be applied in any direction we
please, as there is nothing to spill and the gas is
propelled by a certain force which is always the
same, it will burn equally well in an almost hori-
zontal as in an upright position; and we can thus
obviate two great objections to all our artiﬁcial
lights, that their least luminous end is directed
downwards where the light is generally most
wanted, and that a shade is cast below by the
stand or support of the combustible matter.

The size, shape and intensity of the gas-ﬂame
may be regulated by simply turning a stop-cock
which supplies the gas to the burner. It may at
command, be made to burn with an intensity
sufﬁcient to illuminate every corner of a room, or
so low and dim as barely to be perceived. It is
unnecessary to point out how valuable such lights
may be in nurseries, stables, warehouses, in the
chambers of the sick, &c.

From the facility with which the gas-ﬂame can
be conveyed in any direction, from the diversiﬁed
application, size and shape which the ﬂame can
bemade to assume, there is no other kind of light
so well calculated for being made the subject of
splendid illuminations.

Where lustres are required in the’ middle of a
room, the best mode of conducting the gas to'thev

142 . A TREATISE ON GAS-LIGHT.

chandelier, is to pass the gas-pipe through the
ceiling from the room above, immediately over
the lustre. This can be easily done Without in-
jury to the apartment.

Where side—lights and chandeliers are required
the tubes need never appear in sight, but may be
concealed in the wall or ﬂoor of the house. When

transparencies are wanted as decorations for
, halls, lobbies, &c. more than light: recesses may
be ﬁlled with different coloured media, or paint-
ings, and any intensity of light may be thrown on
the object.

If a number of minute holes are made in the end
of a gas pipe, it forms as many jets defect, which
have a very brilliant appearance; these may some-
times be placed in the focus of a parabolic reﬂec-
tor. In cases where the-light is required to be
thrown to a distance, other burners are constructed
upon the same principle as the Argand lamp,
forming a cylinder of ﬂame, and admitting a cur-
rent of air both to the inside and outside. '

On comparing the ﬂame of a gas-light with the
ﬂame of a candle whatever its size may be, it ap-
pears just as yellow and dull as the ﬂame of a
common lamp appears when compared with that
of a lamp of Argand. The beautiful whiteness of
gaS—light never fails to excite the surprize and ad-
miration of those who behold it for the ﬁrst time.

A TREATISE 0N GAS-LIGHT. 143

A large ediﬁce or manufactory lighted by gas,
contrasted with one of the same kind lighted by
candles or lamps, resembles a street on the night
of a general illumination, compared with the glim-
mering light of its ordinary parish lamps.

The intensity of one of the parish gas-light
lamps now exhibited in the streets of this metro—
polis, will bear ample testimony of this assertion;
the light of the parish gas-lamps, is to the intensity
of the parish oil lamps as l to 12.

One of the most obvious applications of the
gas-light illumination unquestionably Consists in
lighting streets, shops, and houses ; and let it be
observed, that as this is found safe and economi-
cal, it proves all that the most ardent friends of
the gas-light system can desire. ‘F or in contend-
ing with the common mode of lighting the streets
and shops, the new lights must beat out of the
market the cheapest of all artiﬁcial lights ; and as
it has succeeded in doing this, it shews in the most
satisfactory point of view, the prodigious advan-
tages of gas-lights when compared with the mate-
rials of tallow and oil. ,

The original expence of laying the pipes for con-
veying the gas, tOgether with the cost of the ma-
chinery, is all that is required; the preparation of
the gas being itself a lucrative process, no doubt

144 A TREATISE 0N GAS-LIGHT.

will pay all its expences, besides the interest of
capital, and leave a surplus of proﬁt.

Indeed the application of the coal-gas, as a sub-
stitute for tallow and oil, to illuminate houses,
shops, 8:0. is no longer problematical, a consider-
able eXtent of this capital, together with numerous
shops and houses being already supplied with this
species of light.*

Enough therefore, has been done to prove the
possibility of lighting houses, and streets, with
gas, which would have been regarded twenty
years ago as an extravagant paradox.-1'

*’ The Liberty of Norton Ilalgate, as far as Bishopsgate—street, is
lighted with gas—light, from the Chartered Company’s station at
Norton Falgate; and gas-light pipes are laid from that station as
far as the west end of Cheapside, and in all the streets north of that
great thoroughfare.

In the West end of thci'I‘own, the main pipes for supplying the
streets and houses with light from the Gas—Light Company, extend
through the most eligible parts; from their Establishment in Peter-
street, Westminster, along the line from Pall Mall to Temple Bar,
completely surrounding the parish of St. Martin’s in the Fields. Main
pipes are also placed in tlr; Hay—market, Coventry-street, Long-Acre,
St. Martin’s Lane ; and in the principal parts of the parishes of St.
James and St. Ann.

In the East end of the metropolis, the gas-light mains extend from
Cornhill, to St. Paul’s, Wood-street, Fore-street, &e.—-Consent has
also been given to the incorporated Gas-Light Company for laying
their pipes in the parishes of St. Stephen‘s in the Field; St. Paul, Co~
vent—garden; St. Mary-le-b‘trand; St. Clement Danes ; St. George’s,
Bloomsbury; St. Giles’s in the Fields; St. Andrew’s, Holborn, above
the bars; part of the parish of St. Mary-la-bonne; besides several
other districts, comprehending the whole of the city and suburbs of
W estminster.

t I am informed by Mr. C‘LEGG, the engineer of the Chartered

A TREATISE ON GAS-LIGHT. .145

The Church of St. John the Evangelist, in this
metropolis, has been illuminated, with gas—lights
for upwards of two years; the lights employed in
this ediﬁce is equal to 360 tallow candles, eight
to the pound. The avenues to the House of
Lords and House of Commons, Westminster-Hall,
Westminster-bridge; the house and oﬂices of the
Speaker of the House'of Commons, the Mansion-
house, and many other places, deserve to be
named, as having already adopted this species of
illumination. '

Another advantageous application of the gas-
light must be the supplying of light-houses.

From the splendour and distinguishing forms
which the gas-light ﬂame is capable of assuming,
no light is better calculated for signal;lights than

Gas—Light Company, under Whose direction the new system of
lighting is carried on, that the total length of pipe laid down, as
mains, in the streets of London, amounts already to nearly 15 miles.

In the Eastern part of London, the same Company is engaged to
lay their pipes in the principal parts of Whitechapel, Spitalﬁelds, St.
Luke’s, and the adjoining neighbourhood.

One part of the city of London, extending from Temple—bar to the
West end of Cheapside; from Newgate—street to Holborn Bars, to-
gether with the intervening streets, is also provided with pipes laid
down by another gas-light association, who have opened a new esta-
blishment in Water-lane, Fleet—street, but are unconnected with the
Chartered Company. A third company is projected in Southwark,
and a fourth in the Eastern district of London, creating by a rivalry
of interest, that laudable competition which always proves beneﬁcial
to the public at large, and which cannot fail to accelerate the pro-
gress of this new art of procuring light. ,

U

146 A TREATISE 0N GAS-LIGHT.

this. By means of one single furnace, as much
gas might readily be procured as would furnish «a '
ﬂame of suﬁcient intensity, during the longest
winter night, exceeding i'n brilliancy or intensity
of light any lightrhou-se in Britain or elsewhere.

If every light-house round this island were pos-
sessed of a gas-light furnace, ones-half part of the
enormous expence which they at present require
would furnish a much more brilliant light. The
cheapness of this light and its efﬁcacy for the
purpose, would soon multiply the number of light
houses, and thus most essentially contribute to
the security of navigation on our coast. The gas
may be made to issue from tubes by long narrow
slips, and a surface of ﬂame produced of any
given dimensions, and free from all smoke that
would obscure the reﬂectors.

The ease with which the largest gas-light ﬂame
is instantly extinguished by shutting the stop-cock,
and the readiness with which a long line of gas
catches ﬁre by applying a lighted taper to one ex-
tremity, are properties that cannot fail to recom-
mend it for the purposes of telegraphic commu~
nication-s by night. Another application of the
gas unquestionably might be the lighting of bar-
racks, arsenals, dock-yards, and other establish-
ments where much‘ light is wanted in a small
place

A TREATISE ON GAS-LIGHT. 147

The. annual expence of lighting the barracks
of Great Britain is said to fall little short of
50,0001. a small part of which on the new plan,
would supply them with a much purer and safer
light.

The uses of the gas-lights already enumerated
must of themselves, justify us in attaching great
importance to the discovery, and if reduced to
practice all over the kingdom, would employ a
large capital in a way the most advantageous and
productive. But the utility of this light will be
almost indeﬁnitely increased to the use of private
families. That such an application is practicable,
in all towns of Great Britain, is obvious, from
what has been done already, and that it would be
highly economical and ornamental, there can be
little doubt.

By means of gas we may have a pure and agree-
able light at command in every room of our house,
just as we have the command of water, with this
singular advantage, that these lights may burn for
hours within an inch of the most combustible sub-
stance, without danger, because they neither can
burn down like a candle nor emit sparks. These
properties make the gas-lights a most desirable
light on board our ships of war, where severe re-
gulations are necessary, to prevent danger from
ﬁre, which after all are frequently evaded. The

148 A TREATISE ON ‘G-AS-LIGHT.

gas-light might be used in the store-rooms, and even
in the powder magazine, and the captain ”would
completely command the supply of light by the
possession of the key which opens and shuts the
Stop—cock. A small apparatus which may be
erected at a triﬂing expence would be sufﬁcient
for that purpose.

In shops, counting«houses, and public oﬂices,
the advantages are a white light, nearly equal to
day-light, a warmth which almost supersedes the
use of ﬁres, a total absence of smoke, smell, and
vapour, and great economy of labour.

The heat produced by gas—lights must be ob-
served by every one who has had an opportunity
of attending to it in the most superﬁcial manner,
and the reason why gas-lights produce more heat
than oil or candle-light will not appear strange to
our chemical readers (and who is there now that
does not know something of chemistry?) when it
is considered that the gas-light ﬂame condenses
more air than the ﬂame of oil and tallow, and
consequently must produce more heat.

The ﬂame of gas may be produced in so large a
surface, as to be applied to heat the most spacious
apartments as well as to light them.

If the gas is made to issue by a Circular rim of
about twelve inches diameter; it forms a sort of an
Argand lamp on a great scale, and it is manifest

A TREATISE 0N GAS-LIGHT. 149

\

that a circumference of three feet of ﬂame will
heat the air very rapidly, and with such uniformi-
ty that we need no longer be exposed to the par-
tial heating occasioned by the strong draft of a
large ﬁre. A lamp of this description in the cen-
tre of 'a large room, with a very small ﬁre to secure
a gradual renewal of the air would enable us to en-
joy the most healthful and agreeable temperature.

From trials made on this subject, I am enabled
to state, that three Argand’s lamps, consuming
ﬁve cubic feet of gas per hour, are sufﬁcient to
keep a room 10 feet square at a temperature of 55.
Fahr. when the air without doors has a tempera
ture of freezing.*

In all processes of the arts where a moderate

9* Mr. Damon’s method of ascertaining the comparative quantity
or effects of heat evolved during the combustion of diﬁ'erent inﬂama—
ble gases, and other substances capable of burning with ﬂame, as
stated in his System of Chemistry, vol. I. p. 76, deserves to be recom-
mended to those who are more immediately interested in this subject.
The process, which is simple, easy, and accurate, is as follows :

Take a bladder of any :ize, (let us suppose for the sake of illustra-
tion, the bladder to hold or to be equal in capacity to 30,000 grains of
water,) and having furnished it with a stop-cock and a small jet—pipe,
ﬁll it with the combustible gas, the heating power of which is to be
tried. Take also a tinned iron vessel with a concave bottom of the
same capacity, pour into it as much water as will make the vessel
and water together equal to the above stated bulk of water in the

ladder, viz. 30,000 grains. This being done, set ﬁre to the gas at the .
oriﬁce of the pipe, and bring the point of the flame under the bottom
of the tinned vessel, and suffer it to burn there, by squeezing the
bladder till the whole of the gas is consumed. The increase of tem-
perature of the water-in the tinned vessel being carefully noticed be-
fore and after the experiment, gives very accurately the heating
power of the given bulk of the inﬂammable gas.

150 A TREATISE ON GAS-LIGHT.

heat is wanted the gas-light ﬂame will be found
very advantageous—even on a large scale this
ﬂame may be used with proﬁt. It possesses ad-
. vantages which cannot be obtained from ﬂaming
fuel, where much nicety is required ; because no
fuel can be managed like the ﬂame of coal-gas.
For it is well known, that when too little air is
given to ﬂaming fuel it produces no ﬂame, but
sooty vapour; and if too much air be admitted to
make those vapours break out into ﬂame, the heat
is often too violent. It is a fact, that ﬂame, when
produced in great quantity, and made to burn vio-
lently, by mixing with a proper portion of fresh
air, driving it on the subject, and throwing it into
whirls and eddies, thereby mixing the air with
every part of the hot vapour, produces a very in-
tense heat.

The great power of a gas-ﬂame does hot appear
when we try small quantities of it, and allow it to

It was thus proved—-

Olcliant gas raises an equal volume of water ............ 14 "
Carburettcd hydrogen, or coal-gas ........... . ........... 10
Carbonic oxid....... ........... .. ..... . ............. . 4
Hydrogen ..................... 5

Spcrniaceti oil. 10 grains burnt in a lamp raised 30,000

grains of water . . . . . . ........ . ..................... 5
Tallow .. . . ........... . . . .......................... . 5
W'ax .......................................... . . . 5‘75
Oil of turpentine ..... . . . ............................... 3

Spiritofwine................ ....... ............ 2

 

 

[1. FL faring page: 2152.

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.9
;

    

 

(A TREATISE "ON GAS-LIGHT. 151

to burn quietly, because the air is not intimately
brought into contact with it, but acts only on the
outside; and the quantity of burning matter in
the surface of a small ﬂame is too minute to pro—
duce much effect.

But when the ﬂame is produced in large quan-
tity and is freely brought forward into contact and
agitated with air, its power to heat bodies is im-
mensely increased. It is therefore peculiarly pro-
per for heating large quantities of matter to a vio-
lent degree, especially if the contact of solid fuel
with such matter is inconvenient. i

As the gas-ﬂame may be made to assume any
shape and intensity, and as there is nothing to
spill, it may be exhibited under such variety of
forms and designs, as cannot fail to give rise to
the most tasteful ornamental illumination.

PLATES III, IV, and V, exhibit such designs of
different kinds of gas-lamps, chandeliers, lustres,
candelabras, 8:0. as are already in use in this me—
tropolis.

PLATE———III. FIG. 1. Represents a Rod Lamp.
The gas passes through the rod a, to the Argand
burner, which is surrounded by a cylindrical chim-
ney, c, swelling out at the lower extremity. The
construction of the Argand burner we have men-
tioned already, p. 94.

In all the gas-light burners, constructed on Ar-

152 A TRE’ATISE 0N GAS-LIGHT.

gand’s plan, care should be taken that the ﬂame
be in contact with the air on all sides, and that
the current of air be directed towards the upper
extremity of the ﬂame. This may be effected by
causing a current of air to rise up perpendicular
from the bottom of the chimney glass, and to pass
out again through the contracted part, or upper
extremity of the chimney; but no other current
of air should ever be committed to come near the
gas-ﬂame, or enter the glass chimney which co-
vers or defends the light; for if more air be per-
mitted to mix with the ﬂame than is sufﬁcient for
the complete combustion of the coal-gas, it neces-
sarily diminishes the heat, and consequently re-
duces the quantity of light.

FIG. '2. A Rod Gas Lamp, with branches.
The gas passes through the hollow rod, 0, and
part of the hollow branch, I), to the burner of the
lamp. The cylindrical shaped glass, 0, exhibited
in this ﬁgure, is not so well adapted for the com-
plete combustion of coal-gas, as the belly-shaped
chimney, 0, represented in ﬁg. 1, 3, 5, 6, because
the ascending current of fresh air is not turned
out of its perpendicular course, and thrown im-
mediately in a concentrated state, into the upper
part of the ﬂame Where the combustion of the gas
is less perfect. .The exterior current of air which
enters at the bottom into the lamp, rises merely

A TREATISE ON GAS-LIGHT. 153

with a velocity proportioned to the length of the
cylinder, and to the rarefaction of the air in the
same, but without being propelled to the apex of
the ﬂame, as it should do, and is made to do, in
the bellied glass adapted to the lamp, ﬁg. 1.

FIG. 3. A Branch Lamp. a, the tube which
conveys the gas to the burner; b, the stop-cock
of the tube.

FIG. 4. A Pendent Rod Lamp; in which the
gas is supposed to come from a pipe above,
through the ceiling, into the pipe, (1, to supply the
burners. The tulip-shaped chimney, b, of this
lamp, is likewise ill adapted for gas-light burners.

FIG. 5. A Pendent double-branch Lamp. The
gas passing through the perpendicular tube, a,
into the brackets, bl); c shows the Argand bur~
ner.

FIG. 6. A swing Branch Lamp. a, the gas-
pipe with its stop-cock; b, a brass ball, commu-
nicating with the pipe, at; c, the conducting tube,
ground air-tight into the ball, I), and communi-
cating! w1th the burner of the lamp, so as to al-
low it to have an horizontal motion.

FIG. 7. Shews the construction of the ball 6,
and pipe c, of the lamp, ﬁg. 6.

FIG. 8. A swing Cockspur Lamp, constructed
upon the same plan as ﬁg. 6. These two lamps

x

154 - ‘ A TREATISE 9N sysmmnr.

are very convenient for desks in counting-houses,
&c. , ' ' '
FIG. 9. A stop-cock with ball and socket,
which, when adapted to a gas-light pipe, allows
it to have an auniversal motion, so that the light
may be turned in any direction.

. FIG. 10. Section of the stop-cock, with ball
' «and socket. ’“

FIG. 11. Shows the ball and socket, ﬁg. 9, in
perspective. '

PLATE IV,* ﬁg. 1. A Candelabrum; the gas
pipe ascending from the ﬂoor of the apartment,
through the column a, and terminating in the bur-
ner of the lamp.

FIG. 2. A fancy pendent Cockqna' Lamp. The
gas being transmitted to the burners, c c, by means
of the pipe, (1.

FIG. 3. A Pedestal Argand Lamp. a, the
pipe and stop—cock, which transmits t0, and shuts
off the gas from the burner 0f the lamp.

FIG. 4. A Pedestal Coclrspar Lamp. (1, the
stop-cock and gas-pipe.

FIG. 5. A fancy bracket Cockspur Lamp, in-
tended merely to show that the coal-gas, as it
passes to the burner, is perfectly devoid of colour,

* The gas-lamps exhibited in this plate, are employed in the libra-
ry, counting—house, warehouse, and ofﬁces of Mr. Ackerman.

I

 

 

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V

A TREATISE 0N GAS-LIGHT. 155

and invis1ble. a isa glass vessel furnished at its ‘
oriﬁce with a brass cap, 0, and perforated ball,
out of which the gas-ﬂame proceeds. b, the pipe
which conveys the gas into the glass vessel, a.

FIG. 6. A bracket Argand Lamp. a and b,
the gas-pipe communicating with the burner.

FIG. 7 and 8. A Horizontal Branch Lamp.
a, the gas-pipe, supposed to be concealed in the
ceiling. b3 the communicating pipe, which, toge-
ther with 0, branches out at right angles at d d.
e, are the burners of the lamp.-

PLATE V. ﬁg. 1. A Candelabrum, into which the
gas-pipe ascends from the ﬂoor of the apartment,
the lateral branches communicating with the cen-
tral tube. ‘

FIG. 2. An Arabesque Ckandelier. The gas en-
ters from the ceiling of the room into the rope-
shaped pipe, a, from which it proceeds through
one of the arched ribs, 6 6, into the horizontal hoop,
or pipe, 0. 1

FIG. 3. A Roman Chandelier. The gas enters
through the inﬂexible hollow chain, a, into the
central tube, b, from whence the burners are my»
plied by the lateral branches, 0 0.

FIG. 4. A Gothic Chandelier. The gas is trans?
mitted to the burners through the rope, (I, which
includes a tube, and the communication with the
burners is established through the lateral branches.

156 A TREATISE ON ems-LIGHT.

FIG. 5. A Pedestal Figure Lampi The gas is
here made to pass, by means of a pipe, through
the body of the ﬁgure into the lattice-work plateau,
constructed of hollow and perforated brass tubes.

FIG. 6. A Pedestal Vase Lamp. The gas-tube
enters through one of the claw-feet of the altar-
shaped pedestal, into the glass vase, a, at the bot-
tom of which it joins the tubes communicating
with the metallic corn-ears, b, at the upper extre-
mities of which it forms jets defeu.

FIG. 7. A Girandole. The gas enters through
the bracket, a, and is conveyed to the burners by
the descending tubes [3 1).

FIG. 8. A Candelabmm, having a central pipe,
through which the gas is conducted to the burner
at the top.

OTHER PRODUCTS

OBTAINABLE FROJII COAL:

NAMELY,

COKE, TAR, ESSENTIAL OIL, &c.

 

HAVING thus far considered the nature of coal-
gas as a substitute for the lights now in use, it
will be necessary to attend more particularly to
some other products which are obtained during
the production of this species of light: namely,
coke, tar, ammoniacal liquor, Sac.

Coke.——The substance called coke, which con-
stitutes the skeleton of the coal, or its carbona-
ceous base, is left behind in the retort, after all
the evaporable products have been expelled from
the coal by heat.——See p. 101.

It is sufﬁciently known, that coke is a more
valuable fuel than the coal from which it is ob-
tained.

Hence, immense quantities are prepared in the

158‘ A 11113111151: ON GAS-LIGHT.

large way, but the gazeous and other substances
are lost in the process; employed for carbonizing
the coal.* In the manufacture of coal-gas the
coke comes from the retort, enlarged in size,
and greatly diminished in weight, when compared
with the original coal. In whatever state the'coal
may be when introduced into the retort, the coke
is uniformly taken out in large masses, so that the
refuse coal, or dust, and sweepings of the pit,
which are now thrown away, may be employed
and converted into an excellent fuel. Coke is
decidedly superior to coal for all domestic, and
more especially for culinary purposes; the heat
which'it throws out being more uniform, more in-

' The preparation of coke is as follows :-—A quantity of large coal
is placed 011 the ground in a round heap, of from 12 to 15 feet in dia-
metei; and about; two feet in height; as many as possible of the
large pieces are placed on their ends, to form passages for the air;
above them are thrown the smaller pieces and coal dust. and in the
midst of this circular heap, is left, a vacancy of a foot wide where a
few faggots are deposited to kindle it. Tour or the apertures of this

, kind are formed round the ring particularly 011 the side e\posed to
the wind; there is, how ever, seldom om asion to light it 11 1th \\ ood tor
other masses being generally 011 the, the w01 kmen most heqently use
a tew shovels of coal already bur,11iug \1l11(h acts more rapidly than
wood, and soon kindles the surroundiho‘ pile , as the the spreads, the
mass increases in bulk, puﬂ‘s up, bet omes spong y and light, cakes
into one body and at length loses its volatile parts and emits 110
mote smoke. It then acquires an uml‘oi 111 1011 eolour,ineli11iug a
little to white, in which state it begins to bitak into gaps and (hinks
and assumes the appeaiance of the unde1 part ot a mushroom; at
this moment the heap must be quie kly 10\ mod \1 1th aslu s, ot \1 Incl!
there is always a sufﬁcient provision around the numerous tires, whet-1
the. coke is prepared

A TREATISE 0N GAS-LIGHT. 15S)

tense, and more durable. No ﬂame, indeed, ac
companies it, and it seldom needs the application
of the poker ——that speciﬁc for the ennui of En-
glishmen: but these deﬁciencies are more than
balanced by the valuable property of emitting no
sparks, of giving more heat, and burning free
from dust and smoke.

That coke must give out more heat during its
combustion than coal, will ,at once become obvi-
ous, when we consider that the quantity of Hiat-
ter which, in the combustion of coal is changed
from a solid, to a state of elastic ﬂuidity, must ne-
cessarily carry off a portion of caloric, which then
becomes converted in a latent state without pro-
ducing heat, whilst the glow of the coke radiates
caloric with an intensity unimpaired by any de-
mand of this kind.

It is thus that coke, though somewhat more dif—
ﬁcult of ignition than common coal, always gives
out a more steady, a more lasting, and a more in-
tense heat.

The only inconveniences that attend the use of
coke are, that, as it consumes, it leaves much more
ashes than common coal, charcoal, or wood; and
these much heavier too, which are, therefore, liable
to collect in such quantity as to obstruct the free
passage of air through the ﬁre; and further, that

when the heat is cery intense, these ashes are dis

,

160 A TREATISE 0N GAS-LIGHT.-

posed to melt or vitrify into a tenacious dressy sub—
stance, which clogs the grate, the sides of the fur—
nace, and the vessels. This last inconvenience is
only troublesome, however, when the heat required
is very great. In ordinary heats, such as are pro-
duced by kitchen or parlour grates, the ashes do
not melt, and though they are more COpious and
heavy than those of charcoal or wood, they do not
choke up the ﬁre, unless the bars of the grate be
too close together.

The relative effects of heat produced by coke
and coal are as follows :—

Six hundred pounds of pit-coal are capable of
evaporating 10 cubic feet of water in 20 hours,
and 4301b. of coke are capable of evaporating 17
cubic feet of water in 12 hours and a halfﬁ“

‘* In order to learn the relative effect of different kinds of fuel,with
regard to their capability of producing heat, chemistry teaches that
equal quantities of thel alike expended, will raise the temperature of
a given quantity of water through the same number of degrees;
whence, by knowing the original quantity and temperature of water,
together with the quantity of fuel expended to raise the water to the
boiling point, the result sought may be expressed by stating the quan-
tity of water at 30 degrees, which would have been raised 180 degrees
by one pound of the fuel employed; or in the form of a rule,

Multiply the quantity of water by the number expressing the degrees
actually raised ; multiply the number of pounds of fuel expended by 180
degrees. Divide the ﬁrst product by the latter, and the quotient will
express the water which would have been raised 180 degrees by one
pound ofthe fuel. Or equal (plantities of water may be completely
evaporated under equal surfaces and circumstances, With the different
kinds of fuel. the nature of which is to be examined; the quantities
of fuel expended for that purpose give the relative effect of the diller—
ent kinds of fuel. with regard to their power of producing heat.

I A TREATISE ON GAS—LIGHT. 161

The Earl of Dundonald has shown that, in the
application for burning lime, a quantityof coke
uniformly burns a given portion of lime—stone in.
one-third part of the time that the quantity of coal
from which the coke had been made could do.

This effect is to be accounted for from having
previously freed the coal, or rather its coke, from
the moisture and the tar, which it sends out dur-
ing combustion, and which condenses on the mid-
dle and upper strata of stratiﬁed limestone and
coal in the lime-kiln, and impedes the whole mass
of materials from coming into a rapid and com-
plete ignition,- because the, greater the quantity of
materials, and the sooner the whole is ignited, the
better and more economically the lime is burned,
both as to coals and time; the saving of which last
is a material object, especially at lime-kilns where
there is in the summer time a great demand for
lime, the coke occasioning the kilns to hold a
third more lime at the same time.

In the art of making bricks, in the smelting of
metallic ores, and the drying of malt, the advan-
tages of coke over coal, are sufﬁciently known.

The following account given by Mr. Davis}
shows that the advantages that may be derived in

’ Philosophical Magazine, Vol. 33. p. 433.
Y

102 A TREATISE ()N GAS-LIGHT.

- the processes of burning lime, 'plaster of paris,
and bricks, by means of coke, are greater than at
ﬁrst sight might be imagined.

“ The coke obtained in the gas process is so
valuable, that it appears inexplicable that men
should not avail themselves of this mode ‘of pro-
curing light, to the almost total exclusion of all
other methods now in use. As a landholder,
placed among an industrious but wholly illiterate
society of men, I have had the more opportunity
‘ of trying this species of fuel or coke, which I
could not otherwise procure in this sequestrated
spot, at a tolerably cheap rate, for purposes to
which it has not, as far as I know, been hitherto
employed. I must tell you that I am my own
lime-burner, plaster of paris baker, and brick-
maker; and that in these processes of rural eco-
nomy I have derived the greatest beneﬁts from
this species of fuel, which I now prepare at a
cheap rate, although I waste almost the whole of
the light of the coal gas intentionally. The coal
which I employed formerly for the burning of
limestone into lime, is a very inferior kind of
small coal, called liere Welsh culm. The kiln
for burning the limestone into lime is a cup-shaped
concavity, surrounded with solid brick-work, open
at the t0p, and terminating below by an iron grate.
It has a stone door that may be opened and closed

A TREATISE ON GAS—LIGHT. 163

for charging and emptying thevfurnace when re-
quired. This furnace I formerly \charged with al-
ternate strata or layers of small coal and limestone,
the latter being broken previously into pieces, not
larger than a man’s ﬁst, until the kiln was com~
pletely ﬁlled. The stone is thus slowly decom-
posed; the upper part of the charge descends,
and when it has arrived at the bottom of the fur-
nace new strata are super-imposed, so as to keep
the furnace continually full during a period 0f 50
hours. The quantity of lime I procured With
small coal formerly amounted to 85 bushels. The
strata of coal necessary for the production ofthis
quantity of lime require to be four inches thick,
and the time necessary for calcination was, as
stated already, 50 hours.

“ On applying coke instead of coal, the pro-

duce of lime may be increased to nearly 30 per \

cent. from the same furnace, and the time required
to effect the calcination of this quantity of lime-
stone is reduced to 39 hours: it also requires less
attendance and less labour, and the Whole saving,
thus accomplished, amounts to more than 50 per
cent. on the lime-kiln.

“ I have lately also employed coke for the burn.
ing of bricks. My bricks are burnt in clamps,
made of bricks themselves. The place for the
fuel, or ﬁre-place, is perpendicular, about three

164 p A TREATISE ON GAS-LIGHT.

feet high. The ﬁnes are formed by gathering or
arching the bricks over, so as to leave a space be-
tween each of a brick’s breadth ; and as the whole
of the coal, if this fuel be employed, must on ac-
COunt of the construction of the pile, be put in at
once, the charge of the bricks is not, and never can
be, burnt properly throughout; and the interfe-
rence of the legislature, with regard to the mea-
surement of the clamp, is a sufﬁcient inducement
for the manuﬁtcturer to allow no more space for
coal than he can possibly spare.

If coke be applied instead of coal, the arches,
or empty spaces in the clamp or pile, as well as
the strata of the fuel, may be considerably smaller:
the heat produced in this case is more uniform and
more intense, and a saving of 30 per cent. at least.
is gained.

“ In the baking my own plaster-stone I also em-
ploy coke. The calcination of the stone for 1na~
nure I perform in a common reverberatory fur-
nace, and the men who conduct the process (who
are otherwise averse to every thing new,) are much
pleased with the steadiness of the'ﬁre, and little
attendance which the process requires, when coke
is used instead of coal.

“ These are the few facts I wish to state, with
regard to the useful application of this species of
fuel. which, no doubt, hereafter will become an ob-

A TREATISE ON GAS-LIGHT. 165

Ject of economy of incalculable advantage to in-
dividuals, if its nature be better understood than it
is at present.”

The quantity of coke obtainable from a given
quantity of coal varies accOrding to the nature of
the coal employed. One chaldron of Newcastle
coal produced, upon an average, in the gas-light
manufacture, from one chaldron and a quarterito
one chaldron and a half of well-formed coke. If
the carbonization of the coal has been carried to
its utmost point, the coke produced, has a brilli-
ant silvery lustre. Such coke is excellent for me-
tallurgical Operations, because it stands the, pow-
erful blast of the bellows, but for culinary and
other purposes of domestic economy, the carboni
zation should not be carried so far because the
coke then produced, kindles more readily, and
makes a more cheerful ﬁre.

Coal-tar, Oil, and Pitch—Another valuable pro--
duct obtainable from pit-coal, is coal-tar.”“ This
substance is deposited, in the puriﬁcation of the
coal-gas, in a separate vessel destined to receive it.

The coal-tar is so called from its resembling

"' In the year 1665, Becher, a German chemist, brought to England
his discovery for extracting tar from coal ; this distillation he performed
in close vessels. It is not mentioned'in the records of the time, whe-

ther Becher obtained, 0. rather collected, any other articles than the
tar.

\ .-

166 A TREATISE ON GAS-LIGHT.

common tar in its appearance, and most of its qua—
lities.

Several works have been, at different times,
erected both in England and on the continent, to
procure from coal a substitute for tar; but they
turned out unproﬁtable speculations. In 1781,
the Earl of Dundonald invented a mode of dis-
' tilling Coal in the large way, which enabled him
not only to form coke, but, at the same time, to
save and collect the tar. Even this process, how-
ever, for which a patent was taken out, has gained
very little ground. Its object was still too limited;
for though some of the ingredients of coal were
procured, they were. procured at an expense that
nearly balanced the proﬁts ; and no attention what-
ever was paid to the coal-gas which constitutes
the most important part of coal.

Coal-tar may be used with advantage for paint-
ing and securing wood that is exposed to the ac-
tion of air or water. The wood being warmed,
the tar is applied cold, and penetrating into the
pores, gives the timber an uncommon degree of
hardness and durability.

One chaldron of Newcastle coal produces, in
the gas-light manufacture from 150 to 1801b. of
tar, according to the circumstances under which
it is produced. See page 131. ‘

The tar obtained from Newcastle coal is speci-

A TREATISE ON GAS-LIGHT. 167

ﬁcally heavier than that produced from cannel-
coal; hence it sinks in water, whereas the latter
swims on the surface of that fluid.

To render the tar ﬁt for use, it requires to be
evaporated to give it a s’uﬂicient consistence. If
this process be performed in close vessels, 3. por-
tion of an essential oil is obtained, which is known
to colourmen by the name of oil of tar. To ob,-
tain this oil, a common still is ﬁlled with the coal-
tar, and, being properly luted, the ﬁre is kindled
and kept up very moderate, for the tar is very apt
to boil up in the early part of the process. The
ﬁrst product that distils over is principally a brown
ammoniacal ﬂuid, mixed, however, With a good
deal of oil. As the process advances, and the
heat is increased, the quantity of ammoniacal li-
quor lessens, and that of oil increases, and to-
wards the end of the distillation the product is
chieﬂy oil.

The oil and ammoniacal water which distil over
do not mix, so that they may be easily separated
by decantation. ' The oil is a yellowish inferior
kind of oil of turpentine, which is very useful in
painting ships, for making varnishes, and other
coarse out—door work. ‘

i T wo hundred pounds of tar produce, upon an
average ﬁfty-three pounds of essential oil.

If the coal-tar is wanted to be converted into

168 A TREATISE ON GAS-LIGHT.

pitch, without obtaining the oil which it is capa-
ble of furnishing, the evaporation of it may be
performed in a common boiler; but as it is ex-
tremely liable to boil over, the greatest precaution
is necessary in conducting the evaporation. A
boiler constructed on the following plan is very
convenient for the conversion of coal-tar into
pitch. The contrivance consists in adding a spout
or rim, to the common boiler, into which the tar
spreads itself as’it rises, and by this means the
evaporated portion becomes cooled, and the boil-
ing over is checked.

Kettle for boiling Tar.

 

1000 lbs. of coal-tar produce, upon an average,
from 460 to 4801bs. of pitch. A subsequent fu-
sion, with a gentle heat, converts the coal—pitch
into a substance possessing all the characters of
asphaltum.

A TREATISE 0N GAS-LIGHT. 16.9

Ammoniacal Fluid—The properties of the am--
monial liquor, which accompanies the tar, and
which is deposited in the tar-cistern, has not yet
been fully investigated. It is employed already
in the manufacture of muriate of ammonia (sal
ammoniac). One chaldron of coal affords from
220 to 2401bs. of this ammoniacal ﬂuid, which is
composed chieﬂy of sulphate, and carbonate of
ammonia—Such are the products obtainable from
coal.

However certain the practicability of extending
the new lights to the dwelling houses of every
town and village is, it cannot be expected that
such an event should take place speedily and ge-
nerally. To eradicate prejudice, and to alter es-
tablished habits, is a work which nothing but time
can effect; because prejudice is the effect of habit,
and can seldom be eradicated from the minds of
such individuals as consider the ready occurrence
of a proposition as a test of its truth. To esta-
blish a new philosophical theory has, in every in-
stance, required time sufﬁcient to educate an entire
generation of men. The rejection of the Aristo-
telian philosophy—the adoption of experimental
research—the substitution of the doctrine of gra-
vitation instead of that ol‘ vortices, and the rejec-
tion of phogiston by modern chemists, are sufﬁci-
entl y illustrative of this assertion. New arts, and

z

170 A TREATISE _0N GAS—LIGHT.

new practices, are still more difﬁcult to be intro-

duced. , The new art of bleaching need merely be

mentioned to prove this assertion. The new gram-

mar—the new rudiments of science—the new

style-~01- the new instrument, however superior to '
the old in simplicity, facility, and truth, must be

less valuable to the ordinary teacher or artisan,

whose memory is familiarized with the precepts

of the latter, and whose only ambition is to earn

his subsistence with the least possible exertion.

The slowness with which improvements of every
kind, make their way into common use, and es-
pecially such discoveries as are most calculated
to be of an extended or general utility, is very re-
markable, and forms a striking contrast to the ex-
treme avidity with which those unmeaning changes
are adopted, which folly and caprice are continu-
ally sending forth into the world under the au-
spices of fashion.

On the ﬁrst view of the subject it appears very
extraordinary, that any person should neglect, or
refuse to avail himself of a proposed invention, or
improvement, which is evidently calculated to eco-
nomise his labour, and to increase his comforts;
but when we reﬂect on the power of habit, and
consider how difﬁcult it is for a person even to
perceive the disadvantages or imperfections of
former modes to which he has been accustomed

A TREATISE 0N GAS-LIGHT. 17]

from his early youth,.our surprize will be diminish:
cd, or vanish altogether.

Many other circumstances, besides prejudice,
are unfavourable to the introduction of new and
useful discoveries. Among these jealousy, malice,
envy, and revenge, have too often their share in
obstructing the progress of real improvement, and
in preventing the adoption of plans evidently cal-
culated to promote the public good.

A plan like the present, which proposes not
only to trench upon domestic habits, but to give
an entire new direction to a portion of the skill and ‘
capital of the country, must necessarily encounter
the most strenuous Opposition. It is thus that
some individuals have mustered all their strength
against the introduction of this new art. An en-
deavour has been made to move the public opini—
on by dismal forebodings of the Greenland trade,
and the subsequent loss of a nursery of British sea-
men. This objection is nothing more than the
common clamour that is always set up against eve-
ry new means of abridging labour, to which had
the public listened, an interdict'would have been
laid upon the spinning and thrashing machines, the
steam engine, and a thousand other improvements
in machinery.

Indeed such clamour scarcely ever fails to be
made when the extension of machinery and the

172 A TREATISE ON GAS-LIGHT.

abridgement of labour or the application of inani-
mate powers are considered. ’ On such occasions,
it is stated by certain humane, but. mistaken 0b-
jectors, that the scheme of mechanical and che-
mical improvement is pointed against the human
species—that it tends to drive them out of the sys-
tem of beneﬁcial employment—that the introduc-
tion of machinery is injurious to the labouring class
of society, by abridging their work. Two crea-
tures offer themselves for employment and support
——a man and a horse. I must invariably prefer
the latter and leave the former to starve. Two
other beings—a horse and a steam-engine, are can-
didates for my favor. My preference to the latter
tends to exterminate the species of the former. In
both cases it is stated, that the number of intelli-
gent creatures capable of the enjoyment of happi-
ness must be diminished for want of support , and
that on the whole, the sum of the proposed im-
provement is not only a less proportion of good to
society, but a positive accession of misery to the
unemployed poor.

On this wide and extended argument, which
can in fact be maintained against all improvements
whatever, in no other way than by insisting that
the savage state of man, with all its wants, its ig-
norance, its ferocity, and its privations, is prefera-
ble to the social intercourse of eﬂbrt and division

A TREATISE ON GAS-LIGHT. 173

of labour we are habituated to prefer, it may be
suiﬁcient to observe, that it includes matter not
only for reasoning and induction, but also for ex-
periment. By reference to the matter of fact,
though it must be allowed that new improvements,
which change the habits of the poor, must, at ﬁrst,
expose them to a temporary inconvenience and
distress. against which, in fairness, it is the duty of
society to defend them; yet the invariable result
of such improvements is always to better the con-
dition of mankind. A temporary inconvenience
to individuals must often be incurred for the sake
of general national benefit.

It is to manufactories carried on by machinery
and to the abridgement of labour that this country
is indebted for her riches, her independence, and
pre-eminent station among the nations of the
world.

But let us return to the subject. The progress
of the new mode of lighting with coal-gas can ne-
ver wholly supersede the use of candles and
Inoveable lights. The objection with regard to the
Greenland trade is equally futile. This trafﬁc,
might with more propriety be called a drain, than
a nursery, of the naval force. The nature of the
Greenland service requires that the crew should
consist :chieﬂy of able-bodied sailors; and being
protected men, not subject to the impress law,

174 A TREATISE ON GAS-LIGHT.

they are thus rendered useless for national de-
fence. The nursery of British seamen is the coast-
ing trade; and if the gas-light illumination be put
in practice to a large extent, it will increase that
trade as much as it will diminish the Greenland
ﬁshery.

Even on the extreme supposition that it would
annihilate the Greenland ﬁsheries altogether, we
should have no reason to regret the event. The
soundest principles of political economy must con--
demn the practice of ﬁtting out vessels to navigate
the polar seas for oil, if we can extract a superior
material for procuring light at a cheaper rate from
the produce of our own soil. '

Indeed the ﬁsheries will ﬁnd ample encourage-
ment, and the consequence of lighting our streets
with gas can prove injurious only to our continen-
tal friends, one of whose staple commodities, tal-
low, we shall then have less occasion to purchase.
There will be less waste indeed, but a greater con-
sumption of coal. The lower classes of the com-
munity are at present very scantily supplied with
ﬁring; and nothing but a reduction of price is ne-
cessary to increase to 'a very large amount the
Whole average quantity of fuel consumed in the
country. The lightness of the coke produced in
the gas-light manufacture diminishing the expence
of land carriage, will facilitate its general diﬂ‘u-r

A TREATISE 0N GAS-LIGHT. 175

Slon—the comforts of the poor W111 be materially
augmented, and a number of useful operations in
agriculture and the arts, be carried on, which are
now checked and impeded by the price of fuel.

If ansr additional vent were wanted for the coke,
it will readily be found in the continental market;
coke being much better suited than coal to the
habits, of most European nations.

The gas—light illumination cannot tend to dimi-
nish the coal-trade; on the contrary it will prove.
beneﬁcial to it; it will contribute to lower the
price of the superior kinds of coal, and keep a lo-
vel which cannot be shaken under any circum-
stances; it will contribute to prevent combinations
which do certainly operate to the prejudice of the
public, and do sometimes put this great town at
the mercy of particular proprietors in the north,
who deal out coal in the way they please. The—
competition thus produced, it is impossible not to
_ consider as an advantage, which would prevent, in
future, such combinations, and put those in Lon--
don out of the reach of them.

It is worthy observation, that the annual import-
ation of coal into this metropolis, is above one
million and eighty-eight thousand chaldrons.

It may be objected to the universality of our
conclusion, that the price of coals, differing very
much in different places, will occasion a variat’on

176 A TREATISE ON GAS-LIGHT. '

in the expence of the new mode of illumination.
But there are two reasons "why this should have
less place, because we ﬁnd, in Mr. MURDOCH’s
statement, page 86, that of 600l. the estimated
yearly expence of lighting the cotton mill, 550i.
consist of interest of capital, and tear and wear of
apparatus, leaving the cost of coal only 50L a sum
so triﬂing, when we reﬂect that it replaces 20001.
worth _of candles, that the price of coal, even
where it is highest, can but slightly aﬂ‘ect the ge-
neral proﬁts.

2dly, The coal, by yielding the gas and other
products,——n~amely, tar, pitch, ammoniacal liquor,
&c. of which we have treated already, is con-
verted into a substance, increased in bulk, and in
the power of producing heat, namely, coke; and
as a manufactory generally requires heating as
well as lighting, there will be a gain both ways.
The manufacturer, by distilling his coal, instead
of burning it as it comes from the pit, will save
his candles and improve his fuel. One effort at
the outset, in erecting a proper apparatus, will re-
duce his amiual disbursement, for these two arti-
cles of prime necessity, much in the same man-
ner, (though in a far greater degree) as the farmer
gains by building a thrashing machine and laying
aside the use of the ﬂail.

The principal expence in the pursuit of this

A TREATISE ON GAS-LIGHT. 177

branch of civil and domestic economy is therefore
the dead capital employed in erecting the machi-
nery destined for preparing and conveying the gas;
the ﬂoating or live capital, is comparatively small.
At the same time, were we to offer an advice to
the public on this subject, it would be, that no
private individual resident in London should at.
tempt to light his premises for the sake of econo-
my with coal-gas by means of his own apparatus,
whose annual expence for light does not exceed
60l. because the expence of erecting and attend-
ing a small apparatus is almost as great as one
constructed on a larger scale would be. For if
the quantity of gas wanted is not suﬂicient to keep
the retorts continually in a red-hot or working
state, the cost of the gas will be considerably en-
hanced; because either the empty retorts must be
continued red-hot, or the ﬁre must he suffered to
go out; and the retorts, when cold, cannot be
brought to a working state, that is to say, be made
red hot again, but at a considerable expence of fuel,
which must be wasted to no purpose. Whereas,
if the retorts are constantly kept red hot and in
action, one half of the coal necessary to produce a
giVen quantity of gas, will then be saved. But
when a street, or a small neighbourhood is wanted
to be lighted, and the retorts can always be kept
in a working state, that is to say, red hot, the ope-
2 A

178 A TREATISE on GAS-LIGHT.

ration may be commenced with safety; because
the sum required for erecting the apparatus, and
the labour attending it, togetherwith the interest
of the money sunk, will then soon be liquidated
by the light which it will afford.

Individuals, therefore, may engage in the dis-
tillation of coal, and trade with advantage in the
articles produced by that process, and the light—
ing of cities may be accomplished without the aid
of incorporated bodies ; and parishes may be light-
ed by almost as many individuals as there are
streets in .a parish.

From experiments made by Mr. CLEGG, on the
effects produced by a number of gas-lights, of a
. certain intensity, there is reason to believe that the
streets of small towns might be illuminated at a
cheaper rate, by means of a tower or pagoda, fur-
nished with gas-lamps, than can be done in the or—
dinary way by street lamps: the gas being con—
ducted t0 the top of the building from the appara-
tus below, and the light directed down again, upon
the objects to be illuminated, by means of reﬂec-
tors placed at a certain angle. By this contri-
vance, all the main pipes which convey the gas
through the streets, as well as those collateral
ones that branch out from them to the street lamps,
would be saved and thus compensate for the ex-
pense of the tower.

A TREATISE 0N GAS-LIGHT. 179

The most beneﬁcial application of gas-lights
unquestionably is in all those situations where a
great quantity of light is izvauted in a small place:
and where light isrequired to be most diffused,
the advantages of this mode of illumination arc
the least.~——Hence, as already stated, the lighting
of the parish, or street-lamps only, without light-
ing shops or houses, can never be accomplished
with economy.

\V e have noticed before, the reason why the
price of coals can have little effect upon the gas-
light; because the very refuse, or small coal,
called slack, whichpassesthrough the screen at
the pits mouth, and which cannot be brought
into the market—nay, even the sweepings of the
pit, which are thrown away, may be employed for
the production of coal—gas. It makes no differ-
ence in what form the coal is used, and this cir-
cumstance may contribute to enable the coal—
merchant to furnish coals in larger masses,and as
they come from the mine, instead of increasing
the bulk by breaking them into a smaller size,
which is a practice commonly adhered to. This
unquestionably reduces the value of coals; be-
cause the quantity of radiant heat generated in
the combustion of a given quantity of any kind
of fuel depends much upon the management of

180 A TREATISE ()N GAS-LIGHT.

the ﬁre, or upon the manner in which the fuel is
consumed.

There is one subject more on which it is neces-
sary to speak.~—In the present instance, the pub-
lic has been alarmed, by representations, that the
general adoption of gas-lights would expose us
to innumerable accidents, from the inﬂammable
nature of the gas, and the explosion of the appa-
ratus in which it is prepared, or the bursting of
the pipes by which it is conveyed—But there is
no ground for such fears.

Those who are familiar with the subject will
readily allow, that there is no more risk in the ac-
tion of a gas-light n'iachinery, properly construct-
ed, than there is in the action of a steam-engine,
built on just principles.

The manufacture of the coal-gas requires no-
thing lnore than what the most ignorant person,
with a common degree of care and attention, is
competent to perform. The heating of the gas-
furnace, the charging of the retorts with coal, the
closing them up air-tight, the keeping them red-
hot, and discharging them again, are the only
operations required in this art; and these, surely,
demand no more skill than a few practical les-
sons can teach to the meanest capacity. The
workman is not called upon to exercise his own

A TREATISE 0N GlAs-LIGHT. 181

judgment, because, when theﬁre is properly
managed, the evolution of the gas goes on spon-
taneously, and without further care, till all the gas
is extricated from the coal.

No part of the machinery is liable to be out of
order,~—there are no cocks to be turned, no- valves
to be regulated; nor can the operator derange
the apparatus but by the most violent efforts.
And when the stock of gas is prepared, we may
depend on its lighting power as much as we
depend on the light to be obtained from a cer-
tain number of candles or oil-lamps.

The diversiﬁed experiments ~which have been
made by different individuals, unconnected with
each other, have sufﬁciently established the per-
fect safety of the new lights; and numerous ma-
nufactories might be named in which the gas-lights
have now been in use for upwards of seven years,
where nothing like an accident has occured,
though the apparatus in all of them is entrusted
:0 the most ignorant man.

It would be easy to state the causes which have
given‘ rise to some of those accidents that have
spread alarm amongst the public; but of this it
is not my business to speak at length. It is suf-
ﬁcient, on the present occasion, to state, that
those melancholy occurrences which have hap-
pened at some gas-light establishments which I

182 A TREATISE ON GASeLIGHT.

have had an opportunity of examining, were
totally occasioned by egregious failures committed
in the construction of the machinery. Thus, an
explosion very lately took place in a manufacto ry
lighted with coal-gas, in consequence of a large
quantity of g s escaping into a building, 'i‘vhere it
mingled with common air, and was set on ﬁre by
the approach of a lighted candle. That such an
accidentcould happen, is an evident proof that
the machinery was erected by a bungler, unac-
quainted with the most essential principles of this
art; because such an accident might have been
effectually prevented, by adapting a Waste pipe
to the gasometer and gasometer house. By this
means, if more gas had been prepared than the
gasometer would contain, the superﬂuous quan-
tity could never have accumulated, but would
have been transported out of the building into the
open air, in as an effectual manner as the waste-
pipe of a water cistern 'conveys away the super-
ﬂuous quantity of water, when the cistern is full.
—Such an expedient did not ‘form part of the ma-
chinery.

Other instances might be named, where explo-
sions have been occasioned through egregious mis-
takes having been committed in the erection of the
gas-light machinery, were this a subject on which
I meant to treat.

A TREATISE 0N GAS-LIGHT. 183

That the ceal-gas, when mixed with a certain
portion of common air, in close vessels, may be
inﬂamed by the contact of a lighted body, as has
been stated, page 134, is a fact sufﬁciently known.
But the means of preventing such an occurence in
the common application of gas-lights, are so sim-
ple, easy, and effectual, that it would be ridiculous \
to dread danger, where there is nothing to be ap-
prehended. In speaking thus of the safety of the
gas-light illumination, I do not mean to deny that
no possible circumstances may occur where the
coal—gas may be the cause of accident. It is cer—
tain that the gas when suffered to accumulate in
large quantities, in close and conﬁned places,
where there is no current of air,such as in cellars,
vaults, &c. and where it can mix with common air,
and remain undisturbed, that it may be liable to
take ﬁre when approached by a lighted body; but
I do not see how it is probable that such an accu-
mulation of gas should take place in the apart-
ments of dwelling houses. The constant current
of air which passes continually through the rooms,
is sufﬁcient to prevent the possibility of such an
accumulation ever to take place. And with re-
gard to the bursting of the pipes which convey the
» gas, no accident can possibly happen from that
quarter: because the gas which passes through

184 A TR'ﬁA’I’ISE 0N GAS-LIGHT.

the whole range of pipes sustains a pressure equal
to the perpendicular weight of about one inch of
water only, and such a weight, of course, is Insuf-
ﬁcient to burst iron pipes. Nor could the town
when illuminated by gas-lights, be thrown suddenly
into darkness, as has been asserted might happen
by the fracture of a main pipe, supposing such an
event should take place; because the lateral
branches, which supply the street lamps and
houses, are supplied by more than one main; and
the consequence of a fracture would be only
an extinction of the few lamps in the immediate
vicinity of the broken pipe, because the rest of
the pipes, situated beyond the fracture, would
continue to be supplied with gas from the other
mains, as will become obvious from the sketch ex-
hibited in the next page. 7

A TREATISE 0N GAS—LIGHT. 185

Main pipe, leading from the Gas-light station, or
apparatus, situated in Brick Lane, near Old St. l3“

 

 

Main pipe, leading from the Gas-light ap- t I

 

 

 

 

or station, in Westminster.

* The gasometer at this place is equal in capacity to 22,000 cubicfed.',
1’ The capacity of the gasometer here is equal to 15,928 cubicfett.
; At this station the gasometer is equal in capacity to 14,808 cubicfnet. '

The black lines represent the gas—light mains.
or largest pipes, from which the smaller pipes
branch off: they are connected with each other
at the places marked A B C; and the dotted lines
represent the smaller mains, or collateral branches
before—mentioned. The main pipes are all fur-
nished with valves, or cocks, placed at about 100
feet distant from each other. Now let us suppose
that a mam pipe, in any part of the street marked
in the sketch, Pall Mall, should break, it is evident,
on mere Inspection, that the gas which is passing
through the main in the Strand, and which is also

2 B

paratus or station, at Norton Falgate.

186 A TREATISE ON GAS-LIGHT.

connected with the mains in the Hag/market, Pic-
cadilly, and amenity-Street, would continue to
supply the broken pipe, and the valve nearest to
the fracture being shut, would prevent the loss of
any considerable quantity of gas, and the few
lamps situated between the two valves and the
fracture would therefore only become extin-
guished.

Further, let us suppose a main pipe should
break in Piccadilly; in that case, the valve be-
ing shut on each side of the fracture, the gas
would be supplied from the mains in the Hay.
market and St. James’s Street. And the same
effect would be produced in any part of the town,
supplied with gas-pipes. Besides all this, in the
statement thus far given, we have assumed that
all the gas-light mains are supplied with gas from
one manufacturing station only, but which in rea-
lity is not the case. The range of pipes that
convey the gas is connected with three gas-light
eStablislnnents, situated at different parts of the
town; and the gas which is supplied from these
stations is connected with the whole system of
pipes in the streets.* If, therefore, one of the
manufactories should be annihilated, it would
make no difference, because the lights would be

‘ As shown in the sketch.

A TREATISE ON GAS-LIGHT. 187

amply supplied from the other two manufacturing
stations. Hence it is obvious, that the fracture of
any of the gas-light mains, or even the total de-
struction of one or more of the manufactories them-
selves, would be attended with no serious conse-
quence; and as the system of lighting with gas
becomes more extended, the manufactories, 01‘
stations for supplying it, will also be multiplied, to
give effect and security to the iwhole.

In fact, no danger can arise from the application
of gas-lights in any way, but what is common to
candle-light, and lamps of all kinds, and is the
fault of none of them. Even in this case the gas-
lights are less hazardous. There is no risk of those
accidents which often happen from the glittering
or burning down of candles, or from carelessly
snuﬂing them. The gas-light lamps and burners
must necessarily be ﬁxed to one place, and there-
fore cannot fall, or otherwise become deranged,
without being immediately extinguished. Besides,
the gas-light ﬂames emit no sparks, nor are any
embers detached from them. As a proof of the
comparative safety of the gas-lights, it need only
be stated, that the Fire-oﬂices engage themselves
to Insure cotton-mills, and other public works, at
a less premium, Where gas—lights are used, than
in the case of any other lights.

188 A 'I‘REATISE 0N GAS-LIGHT.

It requires .here to be stated, that Mr. CLEGG
‘has invented a selflewtinguishing gas-lamp, so con-
structed, that the gas cannot ﬂow to the burner,
when the ﬂame becomes extinguished. If, there-
fore, the lamp should be blown out, and the stop-
cock which supplies the gas be left open, the
extinction of the ﬂame will effectually shut the
valve. The action of this lamp depends upon
the expansibility of a metallic rod, heated by
the ﬂame of the lamp, and thus keeping open the
valve, whereas, when the lamp is extinguished,
and the rod becomes cold, it contracts to its natu_.}
ral dimensions, and, by that means, effectually
closes the valve. The same engineer has in-
vented a machine, which both measures and re-
gisters, in the absence of the observer, the quantity
of gas delivered by any pipe communicating with a
gas-light main. T he machine occupies a space of
about two feet by one foot, and if put up in a room,
house, or other place, where gas is burnt, will, at
any time, by mere inSpection, give an account of
the quantity of gas consumed in that place during
any given time. On the present occasion it would
not become me to say more on these subjects,
which, no doubt, Mr. CLEGG will make known to
the public; I shall only remark, that these contri-
vances do signal honor to the talents and abilities
of the inventor; and that they will render the

A TREATISE 0N GAS-LIGHT. 189

greatest services to those who are engaged in'the
gas—light illumination.

The excessive expence of insurance arising from
the numerous candles employed in most of the
ﬁrst rate manufactories, and the combustible na-
ture of the structure of the buildings; the great
diﬂi:,:nlty of retrieving the injury resulting to a.
well-organised business, from the accidental de-
struction of the machinery, are objects alone suf-
ﬁcient to furnish the strongest economical, as well
as lmlitical recommendations, for the adoption of
the new lights in all manufactories where work is
done by candle-light.

After considering the facts so far detailed, many
other advantages, connected with the gas-light il—
lumination, Will naturally suggest themselves to
the reader. I have endeavoured merely to point
out the leading characters of the new lights, as they
are at present. Ingenious men may speculate
from what has been done to what remains to be
effected; which, no doubt, will embrace objects
of the greatest utility and most extended national
importance. The public attention is awakened to
the new properties of coal, and will not rest till
they are extensively applied to economical pur-
poses. .The consequence will be a considerable
defalcation in the revenue. For, in proportion as

h the gas—lights are more or less generally adopted

190 . A TREATISE 0N GAS-LIGHT.

in all towns of the country, the consumption of oil
and tallow will be diminished, and the impost on
those articles become less productive; and when
this takes place, government, no doubt, will share
in the proﬁts, by levying a tax on the newlights.
The Exchequer will thus have nothing to fear; as
one branch of the revenue fails, another, and a
more productive one, will supply its place.

Upon the whole, when we reﬂect that the ob-
j ect of the gas-light illumination is to open a source
of national wealth, of which nothing can deprive
us, to create, we may almost say, new articles of
value, its friends cannot be thought guilty of great
presumption, if they look forward with conﬁdence
to the successful extension of this new art of civil
ecOnomy; and if, contrary to all expectations, the
effects of jealousy and prejudice should, in some
respect or other, continue here and there its inﬂ u-
ence against this new art of procuring light, a ﬁrm
perseverance of its application must at length re-

move that ignorance which alone can give them *
birth.

191
TABULAR VIEW,

EXHIBITING

The quantity of GAS, COKE, TAR, PITCH, ESSENTIAL OIL, and AMMONIACAL LIQUOR, obtainable
from a given quantity of COAL; together with an Estimate of the quantity of Coal necessary to
produce a quantity of Gas, capable of yielding a Light equal in duration of Time and intensity
to that produced by Tallow Candles of different kinds. '

. 3 .5" Candles,»~
Cost of Coal. lVeight of Coal. Produce of Gas, in cubicfeet. :9: § 3 9,516 11 t0 “1‘? pound.

53 8. ._ 8,651 10 ditto

(‘1 [1 f C hiinimnm. Maximum. Average. Minm. Maxm. Average. Minm. Maxm. Average. :3 a.) 3 7,786 9 gigo
0150161356028 033,: } 405 10605 50.9 2,800 to 3,136 —— 2,968 8,906 to 11,872 ~— 10,3884: 5? E 2:22;; 3 dittg
Ono’l‘on ............ 30s to48s __38s6d 2,240 6,720 to 8,960 -— 7,840 ems-=2 5,194 6 ditto
0110 Sack ........... 3s 4d 10 53 — 4s 2d 233 to 261 ~— 247 741 to 988 -— 814 3 c! g 4,325 5 ditto
Ono Bushel ......... ls 2dto ls 8d —— is 511 ’78 to 87 — 82% 247 to 330 — 290 ’2; H 5 3,463 4 ditto
One Peck .. . . . 3%10 5d—-— 4% 19%‘(0 21,3?— 20!: 61 to 82 -— 71% 51;? go 2,595 3 ditto
One pound ......... % 1 3 to 4 — 3g- 338'; 1,730 2 ditto
* g g 866 1 ditto

l U

COKE.——One chaldron of coal, from 25 to 28 cwt. gives 1% to 1% chaldron of Coke.
TAR.-——One chaldron of coal, from 25 to 28 cwt. gives from 150 to 1801b. of Tarf" or 15 to, 18 ale gallons. lolb. each.
AMMONIACAL LlQUOR.-——0ne chaldron of coal, gives from 220 to 2401!). of Ammoniacal Liquor, or 22 to 24 ale gallons.

' 10001b. of Coal-Tar afford by distillation, from 260 to 265 lb. of Essential Oil, or Napthn.
looolb. of Coal~an produce by mere evaporation, from 460 to 480“). of Pitch.

Tabular View, exhibiting the lllumz'nalini

6,000
4,500
3,600
3,000
2,571
2,250
2,000
1,800
1 ,636
1,500
1,384
1,285
1,200
1,125
1,058
1,000

947

900

857

818

783

750

 

8,000
0,000
4,800
4,000
3,428
3,000
2,666
2,400
2,101
2,000
1 ,846
1,714

1,600 ,

1,500
1,411
1,333
1,263
1,200
1,143
1,014
1,095
1,000

Average.

10,500

 

7,000
5,250
4,400
3,500
3,005
2,625
2,333
2,100

. 1,913

1,750
1,615
1,499
1,400
1,312
1,234

1166
1, 05

1,050
1,000
950
013
875

Burning.

1 hour
2hours
3 ditto
4 ditto
5 ditto
6 ditto
7 ditto
8 ditto
9 ditto
10 ditto
11 ditto
l2 ditto
l3 ditto
14 ditto
15 ditto
16 diito
17 ditto
18 ditto
19 ditto
20 ditto
21 ditto
22 ditto
23 ditto
24 ditto

Candles. 12 to lb.

21,000
10,500
7,000
5,250
4,400
3,500
3,005
2,625
2,333
2,100
1 ,913
1,750
1,615
1,499
1,400
1,312
1,234
1,166
1,105
1,050
1,000
956
913
875

1 ll II II II II I! II II ll II II ll ll H H H II II II H H II II

illlllllll||llllllIIllllllllllllllllllllllllllll

1.02

g power of Coal-Gas, compared with tlze illuminating power
of Tallow Candles of deferenl sizes.

One chaldron of Coal produces, according to weight and quality,
Cubic feet of Gas
From 9,000 to 12,000

a to lb.
10,500
5,250
3,500
2,625
2,200
1,750
1,502
1,312
1,166
1,050
956
875
807
749
700
656
617
583
552
525
500
47 8
456
437

 

N. B. If it be required to know, for how many hours one pound, or
one peck, or one bushel, or one sack, of coal will produce Gas Light
equal to that of a certain number of well-snuffed Tallow Candles, Ihe
proportion of each of the average weights of a pound, peck, bushel, or
sack, to that of the average weight of a chaldron of coal, is as follows:

1 lb. == 2968th part of a chaldron.

One peck 20 = 148th ditto.
One bushel 82 -= 36th ditto.
One sack 248 = 12th ditto.

RULE. Divide with either of the above parts of weight, the number
of lights opposite to their hours, and the product will be the number of
lights burning for the same number of hours.

EXAMPLE. To know how many lights one peek of coal will give for
six hours, divide the 148th part in 3,500 opposite to the numbei of six
hours, the product is almost 24 lights. The same rule holds good for any
given quantity or number of pounds of coal, in a chaldron, to ﬁnd how
many lights, or candles, 12 to the lb. or 6 to the lb. they will give for a
given number of hours.

(193)

EST I MAT E
ﬂ} 01*
THE PRICE

OF

A GAS-LIGH T APPARATUS,
IF ERECTED IN LONDON,

Capable of alfording, every 24 hours, Light equal to 40,000 Tallow

Candles, six in the pound, burning one hour.

£. 5.

Gasometer, to contain 10,000 cubic feet of gas. . . . 236 0
Wheel—work, regulating chain, balance—weight for

ditto, with wooden framing ................ 160 11
Wrought iron cistern for gasometer~36 feet wide,
24 feet long and 16 feet deep ........... . . . . . 500 0

(It would weigh about 16 tons.)

Wooden framing built around it, to secure ditto. . . . 150 0
Condenser, cistern and communicating pipes ..... 126 0
Lime machine, made of cast iron plates . . . . . ....... 82 0
Gasometer-house, built of frame-work and weather.

boarded ........ ~ ......................... 250 0
Twenty-four retorts set in brick-work, with furnaces

for ditto, complete ................... . ..... 336 o

Sundries........................ 100 0

£ 1940 11
=

A gas-light apparatus complete for work, capable of aﬂ‘ording‘
every twenty-four hours a quantity of light equal to 1,400 Argand’s
Lamps, each lamp equal in intensity to six candles, six in the pound,
burning for ﬁve hours, will cost 3,500]. if erected in this metropolis.

(194)

LONDON PRICE LIST
0f the most essential articles* employed m the Gas-Light

 

apparatus.
SH EET IRON PlPES BRAZED.

{ inch' 111 diameter ......... . 0 4 a footw

gditto.... ...... 0 4 ditto

7} ditto ............ . ...... . 0 5 ditto

% ditto ..................... o 6 ditto 5' a

% ditto ........... .. ....... . 0 6-} ditto a

1; ditto. . .................... 0 7 ditto a
1 inch, ditto.......... ...... . 0>7~§ditto $3
1% ditto ...................... 0 8% ditto an
11 ditto............. ......... o 9 ditto a
11,} ditto. ........ Ologditto E
1-:- ditto.. .......... .......... 011 ditto 0
2inch ditto............."" 1 llditto g
23; ditto ......... 1 4 ditto 9°
21 ditto ............ . ....... . l 5 ditto
8 inch, ditto .............. . . 1 63 ditto J
Coppm pipes b1 *1sz 1 inch. .0 4 per toot
Ditto, ditto, ditto % ........ 0 51 ditto

Gas-light cockspur burners with stop-cock 2s. 6d. to 35. 6d.
Argand’ s lamps, with glass-holders from 3s. to 4s. 6d.
Cast-iron retorts, weighing 7 cwt. at 155. 6d per cwt.. . . .,£ 5 8 6
Mouth—piece for ditto, complete. . . . . . . . . . . . . . . . . ....... 1 l4 8
Cast-iron door homes for 1etort turnace. . . . . . . . . . . . . . . . l 0 0
Finnacc bars lOS. pe1 cwt.
Sheet iron for gasomctei (No. ‘23) 24s.pe1 cwt.
Gasometer chains, 5d. pei lb.
Ballance weiuhts [1P rates] it» gasometcr, 9L 105. per ton.
Cast-i101) cistern p ates

 

smaller size for lime machine, lSl. er ton.
middling size for tar cistern, 16L itto.
~————-——————— largest size tor gasometer cistern 14!. ditto.
Cast-iron ﬂanch pipes” inch diameter, at 53. per yd. 1n 6 feet lengths

ditto 3 ditt to ditto 6 ditto
ditto 4 ditto Ss. 6d. ditto 9 ditto
ditto 5 ditto 10s. ditto 9 ditto
ditto 6 ditto 12s. ditto 9 ditto
ditto 7 ditto 133. 6d. ditto 9 ditto
ditto Bl
3:33 13 Ill. 53. per ton. 9 ditto
ditto l l ‘
§ inch nuts, screws and washers to put 11011 pipes together 7d. per lb.
é ditto .............. ......... ........... . ........ 7d. ditto:
& ditto ............... . . .................... . .. . . . 6d ditto
English bar-iron ..... ............................. 13L per ton.
Best, ditto.......'............. .......... ...... 161. ditto

° All the articles are warranted to be perfect end of the best kind. They are delivered
free of expence, atany wharf between London and \Wstminster— bridge.

FINIS.

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‘ 6

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00

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Marble Slab, Pencils, 8Lc ........... . . . . . 2 1‘2 6
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Highly ﬁnished Mahogany Brass-capped,
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AT PER CAKE.
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In Saucers .. .58. 8c 28. 6d.

Precipitate of Cassius, in

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Fine Chinese Gold, ’in

Saucers ..... 108. 6d. 8C 28.
O Q C O D ls.

Ditto, in Shells. . .
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Bronzmg ......... . . .18.
Gallstone, per Cake. . . . .58.
Royal Smalt, per Cake. . 5s.
Burnt Carmine, do ....... 58.
. . . . . 3S.
Sepia........do........9.s.

Indian Yellow, do . .

 

Carmined Lake, per Cake

ls. 6d.
Purple Lake ..........
Madder Lake, very ﬁne 58.
Ditto, do ............ 28.
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Shells. ........ ......18.
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£133 ‘2,“

 

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