ORNAMENTAL

BRICKWORK.

No, 43, St. Martin's Lane, London.

A

RUDIMENTARY TREATISE
ON T H E M A N U F A C T U R E OF

BRICKS AND TILES;
CONTAINING A N OUTLINE OF T H E

PRINCIPLES OF BRICKMAKING.

BY

EDWARD DOBSON, A.I.C.E., M.I.B.A.,
AUTHOR

OF

" THE ART OF BUILDING," " MASONRY AND STONE-CUTTING,"
" FOUNDATIONS AND CONCRETE WORK," ETC., ETC.

REVISED AND CORRECTED BY CHARLES TOMLINSON, F.R.S.

FOURTH EDITION,
WITH ADDITIONS BY ROBERT MALLET, A.M., F.R.S., MJ.C.E., ETC,

LONDON:
VIRTURE AND CO., 26, IYY LANE.
NEW YORK: VIRTUE AND YORSTON.
1868.

THE AUTHOR'S PREFACE.
THE preparation of this little work has necessarily extended over a considerable period of time, and, although
our limits preclude anything like an attempt at a complete view of the principles and practice of Brickmaking, it will be found to contain much practical
information which has never yet been published, and
descriptions of processes which are little known beyond the localities where they are practised. The
whole of the illustrations have been drawn expressly
for the work, and the descriptions of tools and processes have been written from personal observation,
no dependence having been placed on verbal description^ even hy experienced workmen. Working brickmakers are mostly illiterate men, unable to describe
correctly their own operations, and still less to explain
their meaning. I have therefore considered it necessary
to have every process here described carefully watched
throughout, either by myself or by some one on whose
accuracy of observation I could place dependence.
In the course of last autumn I drew up several papers
M questions, embracing a variety of points on which it
y a s found difficult to obtain correct information, but
which were distributed amongst those of my friends
;who were likely to have opportunities of ascertaining
what was required.

IV

THE AUTHOR'S PREFACE.

Many of these papers in course of time were returned,
accompanied by valuable details, and I have to express!
my thanks and obligations to many gentlemen personally unknown to me for the assistance thus afforded.
Amongst those from whom I have received valuabJ*
assistance during the progress of the work, I ma
especially mention the names of Mr. Arthur Aikin
Mr. John Lees Brown, of Lichfield; Mr. Williai
Booker, of Nottingham; Mr. Richard Prosser, of Birmingham; and Mr. Frederick Eansome, of Ipswich.
Mr. Richard Prosser has kindly contributed a valuable
account of the practice of Brickmaking in Staffordshire, which will be read with much interest, and it will
be worth the reader's while to compare the processes
described in this chapter with those made use of in the
neighbourhood of Nottingham, described in Chapter I I I .
The details given in Appendix I. respecting the manufacture of Suffolk bricks were kindly furnished by Mr.
Frederick Ransome, to whom I am also indebted for
drawings of a Suffolk kiln, which were intended by
him as a contribution to the work, but which, unfortunately, were committed to the post for transmission, and never reached their destination.
In collecting the information requisite for writing the
accounts of Brickmaking and Tilemaking as practised
in the neighbourhood of London, I am under great obligations to Mr. Adams and Mr. Randell, of the Maiden
Lane Tileries, and to Mr. Samuel Pocock, of the Caledonian Fields, Islington, for the kindness with which
they afforded me facilities for inspecting and sketching
their works, and for the liberal manner in which they
furnished me with details of prices and quantities.
Although much time and pains have been bestowed
upon the work, there is so much difilculty in writing a

T H E AUTHOR'S PREFACE.

V

strictly accurate account, even of a simple operation, that
I; cannot hope that it is perfectly free from errors; but 1
tjrust that they are only of a trivial nature, and I shall
He greatly obliged to any reader who will point out any
^missions or mis-statements, that I may be able to
^orreet them in a future edition.
V \ There has long been a want of rudimentary treatises
#iin the Materials of Construction, published in a cheap
-form, and written in a simple and practical style,
divested of scientific technicalities, which render such
(books nearly useless to those by whom they are most
iieeded. I venture to express a hope that this work may
llpe of service in supplying this deficiency with regard to
pne very important class of building materials. At the
^ame time it must be observed that the Science of Bricksnaking is as yet untrodden ground, comparatively little
ibeing known of the manner in which different substances mutually act upon each other when exposed to
furnace heat, or of the relative proportions of silica,
- ^lumina, lime, and other usual ingredients of brickearths, which are best calculated to produce a sound,
well-shaped brick, of a pleasing colour. All that I have
Attempted here, therefore, is to give a clear description
< f the actual manufacture of bricks and tiles, and to
b
Explain the leading differences which exist in the manner
< f conducting the several operations of Brickmaking in
p
yarious parts of this country. How far I have succeeded
in this attempt the reader alone can determine.
EDWARD DOBSOJST.
f OJtfDON, 1850.

PREFACE TO THE FOURTH EDITION.
work was revised by Professor Tomlinson in 1863,
and some matter become useless by time and the alteration of the Excise laws judiciously expunged. A chapter1
was at the same time appended on making bricks by
machinery, but since that period many improvements
and new inventions have necessitated a supplemental!
chapter, in which the editor has endeavoured to give;
an outline of that part of t]ie subject reaching to the
present day. He has also added a sketch of that which
was properly called by the author of the work the Science
of Brickmaking. A few notes, revising the text gene^
rally, will be found in the Appendix, and to which the)
alphabetical index now given affords easy reference.
Though small and elementary, this work may probably claim to be the most complete upon its subject
in the English language.
THIS

ROBERT MALLET.
August, 1868.

CONTENTS.
K.B.—The Numbers refer to the Paragraphs and not to the pages, except
where otherwise stated.

INTRODUCTION.

(Pages 1-12.)

I. Early history of the art would not add to our practical knowledge. I I . Burnt brick used in the building of the Tower of Babel; in
the walls of Babylon; both burnt and sun-dried bricks used in ancient
Egypft I I I . Bricks extensively used by the Romans ; the art of brickmaking abandoned at the decline of the Roman Empire; subsequently
revived in the middle ages. IV. Early and extensive use of bricks in
Holland and the Netherlands. V. Brickmaking introduced into England
by the Romans; arrived at great perfection at the time of Henry VIII.;
only used for large mansions in the time of Queen Elizabeth. VI. Brick
generally introduced as a building material in London after the great fire
of 1666; many fine specimens of brickwork still extant, executed at the
beginning of the 18th century. VII. Enumeration of the duties successively imposed upon bricks and tiles; abolition of the distinction
between common and dressed bricks, by 2nd and 3rd Vict. c. 24. VIII.
The new act a great boon to the public. IX. Number of bricks made
yearly in Great Britain. X. Differences in the processes employed in
brickmaking in differents parts of England. XI. Average strength of
various kinds of bricks. XII. Comparison between the crushing strength
of hand-made and machine-made bricks.

CHAPTER I.
GENERAL PRINCIPLES OF THE MANUFACTURE OF BRICKS
AND TILES.
I. BRICKS.

(Page 12.)

1. Classification of the various operations of the bnckmaker.
PEEPAEATION OF BEICK-EAETH.

(Pages 12—25.)

2. Enumeration of qualities to be aimed at in making bricks. 3. Success depends principally on the selection and preparation of brick-earth.
4. Brick-earths may be divided into three principal classes; viz., pure
clays, marls, and loams ; few earths fit for brickmaking without some

S3

viii

CONTENTS.

mixture. 5. Alumina the principal ingredient in brick-earth; cracks
in drying, after being moulded, and will not stand firing; necessary to
add sand to strong clays, to diminish their contraction; Hme and sifted
Dreeze used near London for the same purpose. 6. Composition of fire
clay; mode of making the Dinas fire brick. 7. iFire clay generally
mixed with burnt clay, broken crucibles, &c. 8. Enumeration of principal localities where fire bricks are made ; relative cost of Windsor,
"Welch, and Stourbridge fire bricks. 9. Bricks made of refractory clay,
baked rather than burnt. 10. Composition of fusible earths. 11. London
bricks not made of clay, but of loams and marls. 12. Bricks may be
divided into two classes, baked and burnt; difficulties in treating the
fusible earths. 13. Cutting bricks made from sandy loams, either natural
or artificial. 14. Colour depends not on the natural colour of the clay,
but upon its chemical composition. 15. Bricks might be made of various
colours by the employment of metallic oxides. 16. Floating bricks.
17. Unsoiling. 18. Clay digging and weathering.
19. Stones must be
picked out by h a n d ; injurious effect of limestone in the clay. 20. Grinding. 21. Washing. 22. Cutters made of washed earth mixed with sand.
23. Sufficient attention not generally paid to the preparation of brickearth.
TEMPEEiirGk
(Pages 25—28.)
24. Object of tempering; is effected in various ways ; treading, grinding, pugging,
25. Brickmaking on the Nottingham and Grantham
railway. 26. Use of the pug-mill.
MOULDING.
27.

Slop moulding

and pallet

moulding.

(Pages 28—35.)
28. Description of

slop

moulding. 29. Description of pallet moulding. 30. Description of
moulding table. 31. Brick moulds, their varieties. 32. Difference in
rate of production per stool, according to the process employed. 33. Slop
and pallet moulding sometimes combined. 34. Moulding by machinery.
35. Disadvantages of dense bricks. 36. Method invented by Mr. Prosser
of moulding in the dry state. 37. Defects of pressed bricks. 38. Difficulties in making moulded bricks, arising from warping in the kiln.
39. Dimensions of bricks. 40. Bricks made of various shapes in country
yards, but not generally in London. 41. Bricks with hollow beds.
42. Ventilating bricks.
DEYING.
(Pages 35—38.)
43. Slop-moulded bricks dried on flats, and hacked under cover.
44. Bricks hacked in the open air where brickmaking is conducted on a
large scale. 45. Clamp bricks hacked at once, and not dried on flats.
46. Recapitulation of differences between slop moulding and pallet
moulding. 47. Different clays require different treatment.
BUENING.
(Pages 38—42.)
48. Bricks burnt in clamps and in kilns. 49. Peculiarities of clamp
burning. 50. Three classes of kilns. 51. Management of a kiln.
52. Impossible in a rudimentary treatise to describe all the processes
in use.

CONTENTS.
II. TILES.

IX

(Pages 42—47.)

53. Differences in the manufacture of bricks and tiles. 54. Three
classes of tiles, viz., paving tiles, roofing tiles, and draining tiles, bo.
Business of a tilery includes the making of pottery. 56. Tiles burnt in
the country together with bricks; in London in separate kilns. 57. Draining-tiles principally moulded by machinery. 58. Importance of making
drain tiles a home manufacture. 59. Concluding observations.

CHAPTER II.
ON THE

MANUFACTURE OF BRICKS AND TILES IN
HOLLAND. BY HYDE CLARKE, C.E.
I. BRICKS.

(Pages 47—48.)

Bricks extensively used in Holland.—Dutch clinkers made at Moor,
near Gouda. — Materials for making them; — river slime and sand ;
localities froni whence obtained.—For Flemish bricks the sand is brought
from the river Scheldt.—The slime and sand are mixed and kneaded
together by treading.—Dimensions of paving bricks and Dutch clinks.—
House bricks and tiles made at Utrecht from brick-earth found in the
neighbourhood.—Dimensions of house bricks.
II.

BRICK-KILNS. ,

(Pages 48—51.)

Sometimes made to burn upwards of a million of bricks.—Fire holes
left in the side walls.—Doorway made in the breadth of the kiln.—Sheds
erected; on each side of the kiln to shelter the fires.—Mode of setting the
kiln.;—Mode of firing.
III.

TILES.

(Page 52.)

Varieties of tiles made in Holland.—Clay ground in a pug-mill.—
Kneaded by women before moulding.—'Two moulders, viz., a rough
moulder and a finisher.—Tiles dried first in sheds and afterwards in the
sun.—Moulding of fiat paving tiles.—Iron moulds used in Switzerland.
IV. TILE-KILNS.

(Pages 53—55.)

Tiles burnt in covered kilns with arched furnaces.—Setting.—Burning.—Cooling.—Mode of giving a grey colour.—-Glazing.—Utrecht the
principal seat of the tile manufacture.—Gouda celebrated for pottery and
tobacco-"pipes.

X

CONTENTS.

CHAPTEE III.
BKICKMAKING AS PRACTISED AT NOTTINGHAM.
(Pages 55—59.)
1. Peculiarities in manufacture of bricks near Nottingham. 2. Use
of brass moulds not confined to Nottingham. 3. Object of crushing the
brick-earth between rollers. 4. Advantages and disadvantages of the
use of rollers. 5. Description of brickmaking at Nottingham applies,
with slight variations, to the practice of the neighbouring counties.
6. Brick-earth from the marls of the new red sandstone ; abounds with
layers of skerry and veins of gypsum. 7. Colour of Nottingham bricks.
8. Common bricks made without picking the clay. 9. Preparation of
clay for making front bricks. 10. Manufacture of rubbers. 11. Clay
at Nottingham not generally suited for making roofing tiles. 12. Size
of old and modern bricks.
GENERAL ARRANGEMENT OF A BRICKWORK.

(Pages 59—80.)
13. Locality of existing yards. 14.' Eental and cost of clay. 15. Arrangement of buildings. 16. Description of clay-mill. 17. Addition of
a second set of rollers a great improvement. 18. Eeference to engravings
of clay-mill; mode of boxing up the machinery. 19. Improvement to
conceal machinery. 20. Duty performed. 21. Length of time a" claymill will remain in working condition. 22. Description of Wash-mill.
23. The Tug-mill not used at Nottingham. 24. Moulding sand. 25. Moulding table, description of. 26. Brick mould, description of. 27. Use of
copper moulds confined to small articles. 28. Mould placed on the
moulding table and not upon a stock-board. 29. Plane, description of.
30. The Flats, how prepared; size of. 31. The Hovel, description of;
sometimes provided with flues. 32. Best bricks dried wholly under cover
in fiued hovels. 33. The Clapper, description of; use of. 34. Dressing
bench and dresser. 35. Machinery for pressing bricks; points to be
attained in making machinery. 36. Machine-pressed bricks cheaper than
those dressed by hand. 37. Kiln, detailed description of. 38. Different
mode of constructing the walls. 39. Comparison of the two methods.
40. Reference to engravings. 41. Steps to the tops of the kilns. 42. Sizes
of kilns. 43. Duration of kilns.
PROCESS OF BRICKMAKING.

(Pages 80—$7.)

44. Clay digging. 45. Tempering. 46. Cost of. 47. Moulding, description of process. 48. Drying; laying on flats; hacking. - 49. Time
that should be allowed for drying. 50. Cost of moulding and drying.
51. Tressed bricks. 52. Polished bricks. 53. Size of brick-moulds.
54. Bate of production. 55. Burning; management of the firing.
56. Cost of fuel. 57. Effect of the fire upon the colour of the pricks,
58. Cost of setting and drawing the kiln. 59. Cost of labour in firing.
60. Enumeration of the varieties of hrickware manufactured at Nottingham.

xi

CONTENTS.
GOST OP MANUFACTURE.

(Pages 87—94.)

61. Land cmd brick-earth ; difficulty of estimating rental; cost of clay.
62. Buildings and machinery; difficulty of ascertaining best relative
sizes of workingfloors>hovels, and kilns. 63. 'Approximate estimate of
extent of buildings and plant required for a weekly production of 46,800.
64. Additional buildings required in a yard, where all kinds of brickware
are- made. 65. Enumeration of tools required. 66. Labour, how paid
for. 67. Summary of cost of production. 68. Relative value of different qualities of bricks. 69. Reference to illustrations, figs. 1 to 18.

CHAPTEE IY.
BRICKMAKING AS PRACTISED IN THE STAFFORDSHIRE
POTTERIES. BY R. PROSSER, C.E.
BRICKS.

(Pages 95—96.)

1. Bricks; enumeration of kinds of brick manufactured. 2, Drab bricks
chiefly used for furnace work. 3. Tiles. 4. Clay. 5. Names of strata
in the pottery district. 6. Two examples given of the process of brick
and tile making.
FIRST EXAMPLE—BRICE.MAKING.

(Pages 97—101.)

7. Buildings and plant. 8. Bates of production. 9. Tempering. 10.
Moulding. 11. Drying. 12. Loss of weight whilst drying. 13. Burning, 14. Cost of manufacture. 15. Mental.
DESCRIPTION OF ILLUSTRATIONS*

(Pages 102—105.)

16. Clay-mill. 17. Moulding table. 18. Brick mould. 19. The oven
or cupola.
SECOND EXAMPLE—TILE-MAKING. (Pages 105—111.)

20. Enumeration of articles made at Basford. 21. Weathering and
tempering. 22. Moulding. 23. Drying. 24. The Set. 25. Quarries and
Dust Bricks. 26. Drain tiles. 27. Tile machines. 28. Firing; detailed
description of. 29. Selling prices of different articles.
DESCRIPTION OP ILLUSTRATIONS.

(Pages 111—117.)

30. Moulding bench. 31. Mode of drying tiles. 32. Tile-block and
horse. 33. Mode of setting lower part of oven. 34. Mode of setting
upper part of oven. 35. Desirability of improving the mode of conducting the manufacture of bricks. 36. Expense of carriage. 37. Analysis
of clays, &c.

Xll

CONTENTS.
BRICKMAEING ON THE SOUTH STAFFORDSHIRE RAILWAY.

(Pages 117—119.)
38. Bricks made for this line by Mr. George Brown, of Walsall "Wood.
—Material not clay, but marl.—Description of strata.—Description of
processes employed.—Cost of bricks at the kiln.

CHAPTER V.
BRICKMAKING IN THE VICINITY OF LONDON.
(Page 119.)
1. Subject divided into three heads.
I. MATERIALS AND PLANT.

(Pages 119—138.)

2. Brick-earth divided into three qualities. 3. Strong clay. 4. Loam.
5. Malm. 6. Different modes of preparation. 7. Object of adding chalk.
8. Soil. 9. Sand. 10. General arrangement of a Brickwork. 11. Chalk
and Clay Mills. 12. The Pug-mill. 13. The\Cuckhold. 14. The Moulding Stool. 15. The Brick Mould. 16. The Stock-board. IT. The Strike
and Ballets. 18. The Sack Barrow. 19. The Sack Ground.
I I . PROCESS OF MANUFACTURE.

(Pages 138^-158.)

20. Clay digging. 21. Quantity of clay required per 1,000. 22.
Maiming. 23. Soiling. 24. Tempering. 25. Fugging. 26. Moulding.
27. Sacking. 28. Clamping, requires skill. 29. General principles of.
30. Foundation. 31. Upright. 32. Necks. 33. Firing. 34. Breeze.
35. Proportion required depends on the nature of the clay. 36. Time
allowed for burning. 37. Upright and Outside. 38. Variations in the
mode of clamping. 39. Table of the qualities and prices of bricks made
for the London market. 40. Brickmaking at Cheshunt. 41. Brickmaking practised generally all round London.
III. COST OF MANUFACTURE.

(Page 150.)'

42. Cost divided under three heads.
MATERIALS AND FUEL.

43. Clay. 44. Chalk. 45. Sand.
and wood. 49. Water.

(Pages 159—161.)

46. Breeze. 47. Soil. 48. Coals

MACHINERY AND TOOLS.

(Page 161.)

LABOUR.

(Page 1)62.)

50. Cost of plant.
51. Details of cost.

CONTENTS.

xin

BRICKMAKING AT THE COPENHAGEN TUNNEL, ON THE GREAT

NORTHERN RAILWAY.

(Pages 162—164.)

Description of rollers, drying sheds, and kilns.
REFERENCE TO ILLUSTRATIONS.

(Pages 164—167.)

52 to 59. Description of figures 1 to 21.

CHAPTER YI.
LONDON TILERIES.
INTRODUCTORY.

(Pages 167—169.)

1. The present chapter confined to a description of the manufacture of
pantiles. 2. List of principal articles made at the London Tileries.
BUILDINGS AND PLANT.

(Pages 170—183.)

3. Pug-mill. 4. Sling. 5. The Moulding Shed. 6. The Pantile Table.
7. The Block and Stock-board. 8. The Tile Mould. 9. The Poll.
10. The Washing-off Table. 11. The Splayer. 12. The Thwacking
Frame. 13. The Tile Kiln.
PROCESS OP MANUFACTURE.

(Pages 183—186.)

14. Clay getting and weathering. 15. Tempering. 16. Slinging,
17. Moulding. 18. Thwacking. 19. Kilning.
COST OP MANUFACTURE.

(Pages 186—188.)

20. Tabular view of cost. 21. Selling prices. 22. Differences in the
processes employed in the manufacture of various articles.
23. DESCRIPTION OP ILLUSTRATIONS.

(Pages 188—189.)

CHAPTER VII.
ON THE MANUFACTURE OP ENCAUSTIC TILE3.
(Pages 189—191.)
1. Revival of the manufacture of encaustic tiles. 2. Difficulties
. arising from the unequal shrinkage of differently-coloured clays.
PROCESS OP MANUFACTURE.

(Pages 191—195.)

3. Clay. 4. Moulding. 5. Inlaying. 6. Drying, firing, and glazing.
7. Manufacture of tesserse. 8. Tesselated pavements.

xiv

CONTENTS.

CHAPTEE VIII.
ON THE MANUFACTURE OF BRICKS AND DRAIN-PIPES BY
MACHINERY.
(Pages 195—209.)
Object to deal with principles rather than with minute details. Various
patents for making bricks by machinery. Description of Oates?s brickmaking machine. Crushing strength of bricks made' by this machine.
Machine can utilise materials unserviceable to the hand brickmaker.
Cost of machine. Description of drain-pipe making machine. Hollow
bricks also made by it. Yarious forms of hollow bricks.

CHAPTEB I X .
ADDITIONAL REMARKS ON THE MANUFACTURE OF BRICKS
BY MACHINERY.
(Pages 210—244.)
BY ROBERT MALLET, A.M., F.R.S.

Improvements in brickmaking since 1863. "Whitehead's improved clay
crushing and grinding roller-mill. "Whitehead's pug-mill. "Whitehead's
perforated pug-mill. Portable clay-mill. Composite machines, in which
crushing rollers and horizontal pug-mills are combined. Brickmaking
machines, by "Whitehead, M. Jardin, Clayton & Co. Machine for
working with plastic clay. Brick-pressing machines, by Longley,
Whitehead, and Bradley and Craven. Dry-clay brickmaking machines,
by Hersey and "Walsh, Bradley and Craven, and Wilson of Campbellfield. Tile-making machines, by Page & Co., and Whitehead. Hoflmann's
brick-kiln.
APPENDIX I.
BY CHARLES TOMLINSON, F.R.S.

(Pages 245—261.)
On the plasticity and odour of clay. On drying bricks. On the use of
coal-dust in making clamp bricks. Brickmaking at Great Grimsby.
Brickmaking in Suffolk. On the making and burning of drain-tiles.

APPENDIX II.
BY ROBERT MALLET, A.M., F.R.S.

(Pages 262—272.)*
The science of brickmaking. Coloured bricks. Infusorial siliceous
materials. Plasticity and odour of clay. Water chemically combined or
mechanically present.

RUDIMENTS,
OE THE

ART OF MAKINQ BRICKS AND TILES.

INTRODUCTION.
I. I T would be impossible, in a little volume like the
present, to enter at any length upon the early history
of the Art of Brickmaking, nor would such an investigation, however interesting in a historical point of view,
add much to our practical knowledge of the subject.
It is, however, dpsirable that we should give a few particulars relative to the progress of the manufacture in
this country \ and we propose at the same time to give
a brief sketch of the legal restrictions whiph have been
imposed from time to time upon the modp of conducting the operations of the brickmaker.
I I . The use of brick as a building material, both burnt
and unburnt, dates from a very early period. Burnt
brick is recorded in t\s Biblp tq have been used in the
erection of the tower of Babel; and we have the testimony of Herodotus for the fact, which is confirmed by
the investigations of travellers, that burnt bricks, made
from the clay thrown out of the trench surrounding
B

2

INTRODUCTION.

the city, were used in building the walls of the city of
Babylon. These very ancient bricks were of three
kinds; one of which was very similar to the modern
white Suffolk bricks, and another to the ordinary red
brick of the present day.
Sun-dried bricks were extensively used in ancient
times, especially in Egypt, where their manufacture
was considered a degrading employment, and, as such,
formed the principal occupation of the Israelites during
their bondage in Egypt after the death of Joseph. Very
interesting ancient representations of the processes
employed are still in existence, and throw much light
on various passages of Scripture. Thus, the passage
in Psalm lxxxi. 6, " I removed his shoulder from the
burden; his hands were delivered from the {water)
pots," is strikingly illustrated by pictures still preserved
to us, in which labourers are carrying the tempered
clay on their shoulders to the moulders, whilst others
are engaged in carrying vessels of water to temper the
clay. The Egyptian sun-dried bricks were made with
clay mixed with chopped straw, which was furnished to
the Israelites by their Egyptian taskmasters before the
application of Moses to Pharaoh on their behalf, after
which the obligation was laid on them, to provide their
own straw, which appears to have been a grievous addition to their labour. I t would appear from the details
given, that the Israelites worked in gangs, under the
superintendence of an overseer of their own nation,
who was provided with all necessary tools and mater
rials, and who was personally responsible for the labour
of the gangs.
y
Burnt bricks were, however, also used in Egypt for
river walls and hydraulic works, but, probably, not to
any very great extent.

INTRODUCTION.

3

It is recorded in 2 Samuel xii. 31, that David put
the children of Ammon under saws, and harrows, and
axes of iron, and made them pass through the brickkiln : without entering on the question whether the
Ammonites were made to labour in the brickfields as
the Israelites l^ad themselves previously done during
the time of their bondage in Egypt, or whether we are
to understand that they were put to death with horrible
tortures, as supposed by most commentators, there is
a strong presumption that the implements here spoken
of in connection with the brick-kiln were employed in
the preparation of the clay; and if this view be cor.reet,
the passage is interesting as evidence of the use of
machinery in making bricks at a very early period of
history.
I I I . The Romans used bricks, both burnt and unburnt, in great profusion; all the great existing ruins
at Rome being of brick. At the decline of the Roman
Empire, the art of brickmaking fell into disuse, but
was revived in Italy after the lapse of a few centuries.
The mediaeval ecclesiastical and palatial architecture of
Italy exhibits many fine specimens of brickwork and
ornamental work in terra-cotta; cornices and other
decorations qf great beauty being executed in the
latter material.
IV. In Holland and the Netherlands, the scarcity of
stone led, at an early period, to the extensive use of
brick, not only for domestic but for ecclesiastical buildings, and these countries abound in fine specimens of
brickwork, often in two colours, combined with great
taste, and producing a very rich effect, as in the celebrated examples at Leeuwarden in Friesland. I t is
worthy of remark, that in the fens of Lincolnshire and
Norfolk, where we should naturally have expected to
B 2

4.

INTRODUCTION'.

have found the same material made use of, the churches^
many of which are exceedingly fine specimens of archi?
tecture, are built of small stones, said tq have been
brought from a great distance on packrhorses.
V. Brickmaking appears to have been jntroducecj
into England by the Romans, who used large thin
bricks or wall tiles as bond to their rubble construe^
tions; and such wall tiles continue^ to be used in
England until rubble work ivas superseded by regular
masonry, about the time of the ISforman Conquest.
Brick does not appear to haye come into general use as
a building material until long afterwards.
In the reign pf Ilenry VIII ?J , however, the art of
brickmaking had arrived at great perfection, and the
remains of many buildings erected about this time
exhibit some of |:he finest known specimens of ornamental brickwork.
The following is a list of some of the principal bricl^
"buildings erected at the period of which we speak :—
NAME.

HurstnionGeaus: Castle, Sussex ,
.
Gate of* the Eyehouse in Hertfordshire
Tattershall Castle, Lincolnshire .
.
Lollards' Tower, Lambeth Palace
.
Oxborough Hall, Norfolk .
.
.
Gateway, Jlectory, Hadleigh, Suffolk'.
Old part of Hampton Court
.
.
Hengrave Hall,' Suffolk
.
.
.
Manor House, at East Barsham, Norfolk
Thbrpland Hall, Norfolk .
.
'.
Parsonage pou se, preat Snoring, Norfolk

WHEN BJJILT.

Early in the reign of Henry VI.
Pitto.
A.p. 1440.
A.D. 1454.
About A.p. 1482.
Close of 15th century.
A.p. 1514.
Finished A.D. 1538.
During the reign of Henry VII.
£>itto.
During the reign of Henry VIII. *

Many of these buildings have been engraved in Pughr's
" Examples qf Gothic Architecture/' to which we would
refer the reader. The decorative details of the Manor
House at East Barsham,, and of the Parsonage House
at Great Snoring,, are particularly worthy of notice ^

INTRODUCTION.

5

the panelled friezes-, cornices, and other Ornamental
work, being constructed of terra-cotta moulded to the
required form. The use of terra-cotta for decorative
panels and bas-reliefs appears to have been common
during the reign of Henry V I I I . The gateway of
York Place, Whitehall, designed by Holbein, was de«
corated with four circular panels, which are still pre^
served at Hatfield Peveril, Hants.
The gateway of the Rectory in Hadleigh churchyard
is very similar in character to that at Oxborough Hall>
engraved in Piigin's wbrk, above referred to. It has
been lately restored very carefully, the terra-cotta work
for the purpose being made at the Layham Kilns, near
Hadleigh, in moulds of somewhat complicated constructioil
In the time of Qtteen Elizabeth, brick seems only to
have been used in large mansions. For commbri builds
ings, timber framework, filled in with lath and piaster;,
was generally used, and this construction was much
employed, even when brickwork was in common use,
the brickwork, up to a late period, being merely introduced in panels between the wooden framing;
Vl. On the rebuilding of London after the great fire
of 1666, brick was the material universally adopted for
the new erections, and the 19th Car. I I . c. 11, regulated the number of bricks in the thickness of the walls
of the several rates of dwelling-houses. One of the
resolutions of the corporation of the city of London,
passed about this time, is interesting; it is as follows :•—
(
' And that they (the surveyors) do encourage and give
directions to all builders,* for ornament sake, that the
ornaments and projections of the front buildings be of
rubbed bricks; and that all the naked parts of the walls
may be done of rough bricks, neatly wrought, or all

6

INTRODUCTION.

rubbed, at the direction of the builder, or that the
builders may otherwise enrich their fronts as they
please."
Much of the old brickwork still remaining in London,
in buildings erected at the end of the 17th and be*
ginning of the 18th century, is very admirably executed.
The most remarkable feature of the brickwork of this
period is the introduction of ornaments carved with the
chisel. A fine example of this kind of work is shown
in the Frontispiece^ which is a sketch of No. 43, StMartin's Lane, one of a block of houses built by a
person of the name of May, who about the same time
erected May's Buildings, to which the date of 1739 is
affixed. The house in question is said to have been
intended by Mr. May for his own residence. Its deeo»
rations consist of two fluted Doric pilasters, supporting
an entablature, the whole executed in fine red brickwork; the mouldings, flutings, and ornaments of the
metopes having been carved with the chisel after the
erection of the walls.jVII. It was not till the close of the last century that
bricks were subjected to taxation. The 24th Geo. I I L
c. 24> imposed a duty of 2s. 6d. per thousand on bricks
of all kinds. By the 34th Geo. I I I . c. 15, the duty was
raised to 4s> per thousand. By the 43rd Geo. I I I . c. 69,
bricks were divided into common and dressed bricks^
and separate rates of duty were imposed on each kind.
These duties and those on tiles were as follows:—
* The author is indebted to the kindness of Mr. Edis for this sketch of
one of the most interesting specimens of ornamental brickwork in the
metropolis.
f This fact was discovered some years ago, -when the .house was
undergoing a thorough repair, and the scaffolding afforded facilities for a
close inspection of the ornamentation. Cast terra-cotta imitations of
carved stone for architectural decoration were sent by Mr.' Blanchard to
the Exhibition of 1851, and were strongly recommended in the Jury
Keport, Class XXVIII.

7

INTRODUCTION.

SCHEDULE (A)—DUTIES.
BRICKS AND TILES.
£

8. &

For every thousand bricks which shall be made in Great Britain, not exceeding any of the following dimensions, that
is to say, ten inches long, three inches thick and five inches
wide
.
.
.
.
;
0 5 0
For every thousand of bricks which shall be made in Great
Britain exceeding any of the foregoing diniensions •. . 0 10 0
For every thousand of bricks which shall be made in Great
Britain, and which shall be smoothed or polished on one or
more side or sides, the same hot exceeding the superficial
dimensions of ten inches long by five inches wide .
. 0 12 0
For every hundred of such last-mentioned bricks, exceeding ? The duties on
the aforesaid superficial dimensions
3 paving-tiles.
For every thousand of plain tiles which shall be made in
Great Britain
.
0 4 10
For every thousand of pan or ridge tiles which shall be made
in Great Britain
; 0 12 10
For every hundred of paving tiles which shall be made in
Great Britain hot exceeding ten inches square .
.
. 0 2 5
For every hundred of paving tiles which shall be made in
Great Britain exceeding ten inches square
.
.
. 0 4 10
For every thousand tiles which shall be made in Great Britain, other than such as are hereinbefore enumerated or
described, by whatever name or names such tiles are or may
be called or known .
•* -. .
;
.
* 0 4 10
N.B.—The said duties on bricks and tiles to be paid by the maker
or makers thereof respectively.

By the 3rd William IV. c. 11 (1833), the duties on
tiles* were wholly repealed, and two years afterwards
the duty on bricks was again raised, making the duty
on common bricks 5s. lOd. per thousand,
The brick duties formed the subject of the 18th
Report of the Commissioners of Excise Enquiry, 1836;
and in 1839 these duties were repealed by the 2nd and
3rd Vict. c. 24> and a uniform duty of 5s«. lOd. per thou* By a curious oversight, this Act, which was intended to put roofing
tiles on the same footing as slates, also repealed the duties on paving tiles,
whilst bricks used for paving remained subject to duty as before. Thus
a lump of Clay put into a mould of 10 in. X 5 in. X 3 paid duty, but the
same quantity of clay put into a mould 10 in. square was duty free, because
it came under the denomination of a tile. The manufacturer, and not
the public, reaped the advantage thus given

8

INTRODUCTION.

sand imposed on all bricks of which the cubic content
did not exceed 150 cubic inches, without any distinction as to shape or quality.
V I I I . The new Act was a great boon to the public
as well as to the trade, as, in consequence of the removal
of the restrictions on shape, bricks might be made to
any required pattern; and moulded bricks for cornices,
plinths, string-courses, &c., could be manufactured at
a moderate price. Under the old regulations, alsb> the
brickmaker was precluded fr&m correcting any defect
which might arise from warping or twisting in the
jrocess of drying, without making himself liable to pay
the higher rate of duty. In 1850 the duty on bricks
was entirely repealed.
IX. The number of bricks annually made in Great
Britain is very great; just befcre the duty was repealed,
& charge was made on about 1,800,000,000 bricks
annually. In 1854 the number manufactured was
estimated to be over 2,000,000,000, of which about
130,000,000 were made in the brickfields in and
around Manchester, and about a similar number by
the London briekmakefs. The weigni of this aiiM'al
produce is upwards of 5>400,000 tons> representing
a capital employed probably exceeding £2,000,000.
Comparatively few bricks are made in Scotland, on
account of the abundance of stone in that country.
Those who are not practically connected with engineering* works may find some difficulty in forming a clear
conception of the immense number of bricks annually
made for railway purposes; and which may be roughly
estimated at from 600 to 800 millions annually; In
1821, before the introduction of the railway system,
the number of bricks charged with duty in England
and Scotland amounted to 913,2313000. In 1831 the

INTRODUCTION.

9

number was 1,153,048,581. In 1840 the number rose
to 1,725,628,333.
A common turnpike road bridge over a railway
requires for its construction, in round numbers, 300,000
bricks; and the lining of a railway tunnel of ordinary
dimensions consumes about 8,000 for every yard in
length, or in round numbers about 14,000,000 per
mile.
X. The processes employed in the manufacture of
bricks differ very greatly in various parts of the country.
In some districts the clay is ground between rollers,
and the pugmill is never used. In others, both rollers
and pugmifls are employed. In the neighbourhood of
London the clay is commonly passed through a washmill. Equal differences exist in the processes of moulding and drying. Lastly^ the form of the kiln varies
greatly. In many places the common Dutch kiln is
the one employed. In Essex and Suffolk the kilns have
arched furnaces beneath their floors; in Staffordshire
bricks are fired in circular domed ovens called cupolas;
whilst near London kilns are not used, and bricks are
burnt in clamps, the fuel required for their vitrification being mixed up with the clay in the process of
tempering.
XI. Brinks vary very much in their strength, a point
to which, although of considerable importance, very little
attention is paid. There is a striking difference in this
respect between modern and ancient bricks; a difference very much in favour of those made centuries ago;
and, perhaps, the weakest bricks made are supplied by
London makers. In some experiments by Mr. Hawkes
(a detailed account of which is given in the Builder
for 1861) it was found that of thirty-five kinds of bricks
which were tested, the average strength of the strongest
B 3

10

INTRODUCTION.

was 2,855 lbs.; of those Of medium tenacity, 2jl25 lbs*;
and of those of least strength, 1557 lbs. These bricks
were of the ordinary form, and varied in thickness from
3*25" to 1*7 inches. It was also found that the thinner
kinds of bricks were proportionally stronger than
those which were thicker; the greatest, mean, and least
strengths bf the former being respectively 4,088 lbs.,
2,954 lbs., and 2,070 lbs.
In coin paring weight with strength, it was found
that the average weight of twenty-five bricks from different districts, was 7*85 lbs.> and that the heaviest
bricks were usually the strongest. The results of the
following experiments are calculated according to a
uniform standard:—Tipton blue bricks, weighing 10 lbs.,
gave 5,555 lbs., 3,975 lbs., and 2,801 lbs., as the
greatest, mean, and least degree of strength. Boston
bricks, weighing 9*88 lbs., gave 4,133 lbs.> 3,198 lbs.,
and 2,616 lbs., as the value of the same items. Roman
hypoeaust tiles from the ancient city of Uriconium,
near "Wroxeter, gave 4^670 lbs., 3,567 lbs.;, and
2,630 lbs. The Leeds bricks, weighing 9*17 lbs.,
gave 4,133 lbs., 3,198 lbs., and 2,616 lbs. Dutch
clinkers, with a weight of only 6*56 lbs., gave the respective strength of 4,006 lbs., 3,345 lbs., and 2,542 lbs.
This is an exception to the general result of the heaviest
bricks being the strongest. Lastly, the lightest London
bricks, weighing 6*19 lbs., gave 1,496 lbs., 998 lbs., and
366 lbs. The experiments also gave evidence of the
fact that brickss were unable to sustain for any length
of time a weight considerably less than that which was
originally required to break them ; for example, a Baltimore brick, which required 850 lbs. to break it, carried a weight of 735 lbs. for ten hours only> and then
broke. It must be borne in mind that the second

11

INTRODUCTION*

result is represented in terms of the whole brick, for
the sake of rendering the comparison more easy,
although^ of course, the experiment could only be made
on the half brick.
XII. Now that machine-made bricks are getting
into general use, notwithstanding that some opposition
has been made to their introduction, the following
table may be interesting. It is a report of the results
of some experiments on hand-made and machine-made
bridks, with Messrs. Burton and Co/s hydraulic press.
All the bricks were bedded upon a thickness of felt,
and laid upon an iron-faced plate.
Pressure to crack. Pressure to crush,
tons.
tons.

Good London grey stocks . . .
Best paviours to be got
* ; .
Red bricks, not fully burnt . . .
Ditto, ordinary quality . . . .
Three white bricks made by Clay- )
ton and Co.'s machinery
. )
Ditto, second best, with four bricks

12-00
14'0O
13-75
13-00
,„ ~e
17 05
'
16-25

.
.
.
.

.
;
.
.

.
.
.
.

14-00
23-00
25 05
26-25
.^ ~;
41 05
•
*
'
. . . 41*00

In the following pages we have described at considerable length the practice of brickmaking as carried
on in Nottinghamshire, Staffordshire, Suffolk, and in
the neighbourhood of London; and although the practice of almost every county presents some local peculiarity, the reader who has carefully gone through these
accounts will be enabled to understand the object of
any processes not here described, and to form a tolerably correct judgment as to whether the process of
manufacture in any district is conducted in a judicious
manner; or Whether the brickmaker has merely followed the practices handed down by his predecessors
without any consideration as to the possibility of improving upon thenii Before, however, entering upon
the practical details of the subject, it is necessary that

12

RUDTMENTS OF THE

the reader should have some knowledge of the general
principles of brickmaking, and of the nature of the
processes employed; and these we shall proceed to
consider in the following chapter.

CHAPTER I.
GENERAL PRINCIPLES OF THE MANUFACTURE OF
BRICKS AND TILES.
, 1. BRICKS.

1. The whole of the operations of the brickmakei'
may be classed under five heads, via.:—
Preparation of brick earth.
Tempering.
Moulding.
Drying.
Burning.
We propose in this chapter to describe these operations one by one, pointing out the object to be effected
by each, and comparing at the same time the different
processes employed in various parts of this country for
the same end.
PREPARATION OF BRICK EARTH.

2. The qualities to be aimed at in making bricks for
building purposes may be thus enumerated:—rSoundness, that is, freedom from cracks and flaws ; hardness,
to enable them to withstand pressure and cross strain;
regularity of shape, that the mortar by which they are
united may be of uniform thickness to insure uniform
mity of settlement; uniformity of size, that' all the
bricks in a course may be of the same height; uni-

ART OF MAKING BRICKS AND TILES.

13

formity of colour, which is of importance only in
ornamental work• facility of cutting, to enable the
bricklayer to cut them to any given shape, as required
in executing all kinds of gauged workj lastly, for
furnace-work, and all situations exposed to intense
heat, infusibility.
3. Success in attaining the desired end depends
chiefly on a proper selection of brick earths j their
judicious preparation before commencing the actual
process of briekrnaking, as well as on the drying and
burning of the bricks. The other operations are
matters of minor importance. Briekrnaking may be
viewed in two lights—as a science, and as an art. The
former has been little studied, and is imperfectly understood j whilst the latter has been brought to great
perfection.
4 The argillaceous earths suitable fdr briekrnaking
inay be divided into three principal classes, viz. :—
Pure clays, composed chiefly of alumina and silica^
but containing a small proportion of other substances—
as iron, lime; &c* (See Appendix IL, page 263;)

fit;

* The following analyses of various kinds of clay are given in the)1
second volume of the English translation of "Knapp's Technological
Chemistry."

Silica
Alumina
'Oxide "
1
[ o f iron j
! Lime
Magnesia
Potash 1
)
& soda j
Water .

46*32
39-74

Stourbridge Sire P i p e c l a y .
clay.

64-10
23*15

53-66
32-00

Sandy
clay.

Blue clay.

66-68
26-08

4'6'38
38-04

49-44 1
34-26

Brick
clay.

12-67

99-80

1-35

1-26

1-04

7-74

0-40
trace

0-84
trace

1-20
trace

1-48
5-14

10-00

0*27
0-36
0-44

12-08

5*14

13-57

1-94

100'05

99-49

100-00

100-23

100-00 I

1-85
0-95

14

RUDIMENTS OF THE

Marls, which may be described as earths containing
a considerable proportion of lime.
Loams, which may be described as light sandy clays.
It very seldom happens that earths are found which
are suited for the purpose of brickmaking without some
admixture. The pure clays require the addition of
sand, loam, or some milder earth; whilst the loams are
often so loose that they could not be made into bricks
without the addition of lime to flux and bind the earth.
Even when the clay requires no mixture, the difference
in the working of two adjacent strata in the same field
is often so great that it is advisable to mix two or three
sorts together to produce uniformity in the size and
colour of the bricks.
5. It appears, then, that a chemical compound of
silica and alumina is the principal ingredient in all
brick earth.* This silicate of alumina, or pure clay
alone, or those clays which contain but little sand, may,
when beaten up with water into a stiff paste^ be moulded
with great ease into any shape; but will shrink and
crack in drying, however carefully and slowly the operation be conducted; and will not stand firing, as a red
heat causes the mass to rend and warp, although it
becomes very hard by the action of the fire.
The addition of any substance which Will neither
combine with water, nor is subject to contraction, greatly
remedies these defects, whilst the plastic quality of the
clay is not materially affected. For this reason the
strong clays are mixed with milder earth or with sand.
The loams and marls used for brickmaking in the
neighbourhood of London are mixed with lime and
sifted breeze for the same purpose, and also to effect the
fluxing of the earth, as will be presently described.
* Some remarks on the plasticity of clay will be found in the Appendix.

ART OF MAKING BRICKS AND TILES.

15

6. Fire clays or refractory clays are compounds of
silica, alumina, and waterj or hydrated silicates of alumina represented by the formula AI2O3, 2Si0 3 + 2HO.
Such clays owe their refractory qualities to their com^
parative freedom from lime, magnesia^ metallic oxides,
and similar substances which act as fluxes. Few
clays, however, exist in nature according to this pure
type* The composition and quality of clays in contiguous beds in the same pit, and even of clay from the
same contiguous horizontal bed, may vary. " I f we
compare different clays together in respect to elementary
composition, we find the relation between the silica and
alumina to be extremely variable, and accordingly, the
formulae which have been proposed to express their
rational constitution are very discordant* This is in
great measure to be explained by the fact, that in many
clays a large proportion of silica exists uncombined
either as sand, 01* in a much finer state of division*
The grittiness of a clay is due to the presence of sand/'' *
Eire-bricks are used in those parts of furnaces where
the heat would soon destroy ordinary bricks. They are
made of various shapes and sizes as required, and are
often produced, as in the iron works of South Wales,
on the spot. The clay is ground between rolls, or under
eAdge stones, and kneaded by treading. The bricks are
made by hand in moulds; they are carefully dried in
stoves, and burnt at a high temperature in closed kilns.
Burnt clay in powder is sometimes mixed with the raw
clay. Stourbridge clay is celebrated for the manufacture
of fine bricks, but clay from the coal-measures is also
largely used. All these bricks have a pale brownish
colour) but they are sometimes mottled with dark spots,
* <4 Metallurgy," by John Percy, M.D., F.R.S., Lecturer on Metallurgy
at the Government School of Mines, London, 1861;

16

RUDIMENTS OF THE

which Dr. Percy refers to the presence of particles of
iron pyrites. The Dinas fire-brick consists almost
entirely of silica, the material being obtained from the
rock of that name in the Yale of Neath. It lies on the
limestone^ and occasionally intermixes with it, and
contains probably about 5 per cent, of calcareous matter.
The bricks have extraordinary fire-proof qualities. The
material had long been used as a sand, and many
attempts were made to form it into bricks, without
success, until a method was Contrived by the late Mr.
W. W. Young, when in 1822 a company was formed
for the manufacture of these bricks. The mode of
making the Dinas brick was long kept secret, but a
number of original details concerning it are given in
Dr. Percy's work. The material which is called clay is
found at several places in the Vale of Neath in the state
of rock, and disintegrated like sand. The colour when
dry is pale grey. The rock is crushed to coarse powder
between iron rolls; it softeils by exposure to the air^
but some of it is too hard to be used. " The powder of
the rock is mixed with about 1 per cent, of lime and
sufficient water to make it cohere slightly by pressure.
This mixture is pressed into iron moulds, df which two
are fixed undesr one press^ side by side; The mould,
which is open at the top and bottom^ like ordinary
brick-moulds, is closed below by a moveable iron plate;
and above by another plate of iron, which fits in like a
piston, and is connected with a lever. The machine
being adjusted, the coarse mixture is put into the!
moulds by a workman, whose hands are protected by
stout gloves, as the sharp edges of the fragments would
otherwise wound them: the piston is then pressed
down, after which the moveable bed of irtfn on which the
brick is formed is lowered and taken away with thef

ART OF MAKING BRICKS AND TILES.

17

brick upon it, as it is not sufficiently solid to admit of
being carried in the usual manner. The bricks are
dried on these plates upon floors warmed by flues
ipassmg underneath. •, amd -whew diy they ave piled m a
circular closed kiln covered with a dome, similar to
kilns in which common fire bricks are burned. About
seven days of hard firing are required for these bricks,
and about the same time for the cooling of the kiln.
One kiln contains 32,000 bricks, and consumes 40
tons of coal, half free-burning and half binding. The
price (1859) is 60s. the thousand,"* The fracture
of one of these bricks shows irregular particles of quartz,
and the lime which is added acts as a flux, causing them
to agglutinate, These bricks expand by heat, while
brinks made of fire clay contract. Hence they are
useful for the roofs of reverberatory furnaces, and for
parts where solid and compact lining is required. These
siliceous bricks must not be exposed to the action of
slags rich in metallic oxides.
7. Fire clay, being an expensive article, is frequently
mixed with burnt clay, often as much as two parts by
weight id one of Stourbridge clay. Broken crucibles,
did fife bricks^ and old glass-pots ground to powder are
also mixed with fire clay.
8. Fire clay is found throughout the coal measures,
but that of Stourbridge is considered to be the best, as
it will bear the most intense heat1 that can be produced
without becoming fused. Next in esteem to those of
Stourbridge are the Welsh fire bricks, but they will not
bear such intense heat. Excellent fire bricks are made
at Newcastle and Glasgow. Fire bricks are made near
Windsor, at the village of Hedgerly, from a sandy
In this year bricks were much cheaper than they have been since.

18

RUDIMENTS OF THE

loam known by the name of Windsor1 loam, and much
used in London for fire-work, and also by chemists for
luting their furnaces^ and for similar purposes.
The relative merits of Windsor, Welsh, Stourbridge,
and other fire bricks, are best shown by their commercial value. The following items, extracted from the
"Builders' and Contractors' Price Book for 1868/'
edited by G» R. Burnell, exhibit their relative cost :—
Per 1000.
£ s. d.

Windsor fire briclis
Welsh ditto
.
Stourbridge ditto
Newcastle ditto
Alloa ditto
.
Dorset ditto *

.
.
;
»
*

»
.
.
;
*
4

*
.
*
.
.
.
.
;
4 * *
.
.

*

5 4
. 5 4
. 7 0
4 5 5
* 5 8
4 16
;

0
0
0
0
0
0

9. Bricks made of refractory clay, containing no lime
or alkaline matter, are baked rather than burnt; and
their soundness and hardness depend upon the fineness
to which the clay has been ground, and the degree of
firing to which it has been exposed.
10. I t is very seldom that the common clays are
found to be free from lime and other fluxes • and when
these are present in certain proportions, the silica of
the clay becomes fused at a moderate heat, and cements
the mass together. Some earths are very fusible, and,
when used for brickmaking, great care is requisite in
firing the bricks to prevent them from running together
in the kiln*
11. The earths used for brickmaking near London
are not clays, but loams and marls. To render these
earths fit for brickmaking, they are mixed with chalk
ground to a pulp in a wash-mill. This effects a double
purpose, for the lime not only imparts soundness to the
bricks, acting mechanically to prevent the clay from
shrinking and cracking, but also assists in fusing the

ART OF MAKING BKICKS AND TILES.

19

siliceous particles; and when present in sufficient quantity, corrects the evil effects of an overdose of sand, as
it takes up the excess of silica that would otherwise
remain in an uncombined state.
12. It will be seen from these remarks that we may
divide bricks generally into two classes—baked bricks
made from the refractory clays, and burnt or vitrified
bricks made from the fusible earths.
The fusible earths are the mbst difficult of treatment,
as there is considerable practical difficulty in obtaining
a sufficient degree of hardness without risking the
fusion of the bricks; and it will be found that ordinary
kiln-burnt bricks, made from the common clays, are for
the most part of inferior quality, being hard only on the
outside, whilst the middle is imperfectly burnt, and
remains tender. The superior quality of the London
malm bricks, which are made from a very fusible compound, is chiefly due to the use of sifted breeze,* which
is thoroughly incorporated with the brick earth in the
pugmill, so that each brick becomes a kind of fire ball,
and contains in itself the fuel required for its vitrification. In building the clamps the bricks are stacked
close together, and not as in ordinary kiln-burning, in
which openings are left between the bricks to allow of
the distribution of the heat from the lire holes. The
effect of these arrangements is to produce a steady uniform heat> which vitrifies the bricks without melting
them. Those bricks which are in contact with the live
holes or flues melt into a greenish black slag.
13. Cutters, that is, bricks which will bear cutting
and rubbing to any required shape, are made from
sandy loams> either natural or artificial. In many
* Breeze is a casual mixture of cinders, bmall coal, and ashes, such aa
is collected by the dustmen.

20

RUDIMENTS OF THE

districts cutters are not made, there being no suitable
material for the purpose. „Bricks made from pure clays
containing but little silica are hard and tough, and will
not bear cutting.
14. We now come to the consideration of colour,
which depends on the varying proportions of the
hydrated oxide of iron in the clay, which Change
according to the amount of heat to trhich the bricks
are subjected, and not on their natural colour before
burning. This should be borne in mind, because bricksmakers often speak of clays as red clay, white clay, &c.>
according to the colour of the bricks made from them,
without any reference to their colour in the unburn!
state.
If iron be present in clay without lime or similar
substances, the colour produced at a moderate red heat
will be red, the intensity of colour depending on the
proportion of iron. The bind or shale of the coal measures burns to a bright clear red. If the clay be
slightly fusible, an intense heat vitrifies the outside of
the mass and changes its colour, as in the case of the
Staffordshire bricks, which, when burnt in the ordinary
way, are of a red colour, which, however, is changed to
a greenish blue by longer firing at a greater heat. The
addition of lime changes the red produced by the oxide
of iron to a cream brown, whilst magnesia brings it to
a yellow. Few clays produce a clear red, the majority
burning of different shades of colour, varying from
reddish brown to a dirty red, according to the proportion of lime and similar substances which they contain.
Some clays, as the plastic clays of Suffolk, Devonshire,* and Dorsetshire, burn of a clear white, as may
* The plastic clay of Devonshire and Dorsetshire forms the basis of
the English stone ware. It is composed of about seventy-six parts of

ART OP MAKING BRICKS AND TILES.

21

be seen in the Suffolk Tvhite bricks, which are much
esteemed for tl^eir soundness and colour. The London
malms have a rich brimstone tint, which is greatly
assisted by tfye nature of the sand used in the process
pf moulding.
15. By employing metallic pxides and the ophreous
metallic earths, ornamental bricks are made pf a
variety of cplpurs. This, however, is a branph of brickr
making which has as yet received very little attenfipn,
although, with the rising taste for polychromatic decoration, it is ^vell worthy of consideration. (See note3
page 270.)
Yellow clampt burnt bricks are made in the vicinity
pf the metropolis, and in others situations where
similar material and fuel are readily obtained. White
bricks are made from the plastic plays of Devonshire
and Dorsetshire, and also Cambridgeshire, Norfolk^
Suffolk, and Essex, as well as in other counties. Bed
bricks are made in almost every part of England; but
the fine red or cutting brick is not generally made.
Blue bricks are made in Staffordshire^ and. are much
used in tha£ part of England.
Sound and well-burnt bricks are generally of a clear
and uniform polour, and when struck together will ring
with a metallic sound. Deficienpy in either of these
points indicates inferiority.
16. Bricks sufficiently light to float in ^he water were
known to the ancients. This invention, however, was
completely lost until rediscovered at the plpse pf the
silica and twenty rfour of alumina, with some other ingredients in very
small proportions. This clay is very refractory in high heats, a property
which, joined to its whiteness when burned, renders it peculiarly valuable
for pottery, &c.
* Yellow clampt burnt bricks are made at Margate, in Kent, from the
patches of plastic clay lying in the hollows of the chalk. The older part
of Margate is built of red bricks said to have been brought from Canterbury.

22

RUDIMENTS OF THE

last century by M. Fabbroni, who published an account
of his experiments. M. Fabbroni succeeded in making
floating bricks of an infusible earth called fossil meal,
which is abundant in some parts of Italy. Bricks made
of this earth are only one-sixth of the weight of common
clay brioks, on which account they wpuld be of great
service in vaulting church roofs, and for similar purposes. Ehrenberg, the eminent German microscopist,
showed that this earth consists almost entirely of the
frustules or siliceous skeletons of various kinds of
minute water plants. (See note, page 271 .J
Having thus briefly sketched the leading principles
which should be our guide in the selection of brick
earth, we will now proceed to describe the several processes by which it is brought into a fit state for use.
17. Unsoiling.—The first operation is to remove the
mould and top soil, which is wheeled away, and should
be reserved for resoiling the exhausted workings when
they are again brought into cultivation. In London
the vegetable mould is called the encallow, and the
operation of removing it, encallowing.
18. Clay-digging and Weathering.—The brick earth
is dug in the autumn, and wheeled to a level place prepared to receive it, when it is heaped up to the depth
of several feet, and left through the winter months to
be mellowed by the frosts, which break up and crumble
the lumps. At the commencement of the brickmaking
season, which generally begins in April, the clay is
turned over with shovels, and tempered either by spade
labour or in the pugmill; sufficient water being added
to give plasticity to the mass.
19. During these operations any stones which may]
be found must be carefully picked out by hand, whichj
is a tedious and expensive operation, but one which

ART OF MAKING BRICKS AND T I L E S .

23

cannot be neglected with impunity, as the presence of a
pebble in a brick generally causes it to crack in drying,
and makes it shaky and unsound when burnt. If the
earths to be used are much mixed with gravel, the only
remedy is to wash them in a trough filled with water,
and provided with a grating sufficiently close to prevent
even small stones from passing through, and by means
of which the liquid pulp runs off into pits prepared to
receive it, where it remains until, by evaporation, it
becomes sufficiently firm to be used. This process is
used in making cutting bricks, which require to be of
perfectly uniform texture throughout their whole substance ; but it is tedious and expensive.
In working the marls of the midland districts, much
trouble is experienced from the veins of skerry or impure limestone with which these earths abound. If a
small piece of limestone, no bigger than a pea, is allowed
to remain in the clay, it will destroy any brick into
which it finds its way. The carbonic acid is driven off
by the heat of the kiln, and forces a vent through the
side of the brick, leaving a cavity through which water
finds its way, and the first sharp frost to which such
a brick may be exposed generally suffices to destroy
the face.
20f Grinding.—To remedy this, serious evil, cast-iron
rollers are now generally used throughout the midland
districts for grinding the clay and crushing the pieces
of limestone found in it, and their introduction has
been attended with very beneficial results. The clays
of the coal measures contain much ironstone, which
requires to be crushed in the same manner.
In many yards the grinding of the clay is made to
form part of the process of tempering, the routine, being
.as follows;—clay-getting, weathering; turning over and

24

RUDIMENTS OF THE

wheeling to mill, grinding, tempering, and moulding.
In Staffordshire the clay is not only ground, but is also
pugged in the process of tempering, as described in
chap. iv. art. 3 8 ; the routine is. then as follows :-clay-getting, grinding, feathering, turning oyer, pugging, moulding.
At a well-mounted brickwork in Nottingham, belonging to Moses Wood, Esq., the clay used in making the
best facing bricks is treated as follows :—it is first
turned over and weathered by exposure to frost; it is
then again turned over, an<J the stones picked out by
hand, after which it is ground between rpllers set very
close together, and then left in cellars to ripen for a
year or more, before it is finally tempered for the use
of the moulder. The bricks made from clay thus
prepared are of first-rate quality, but thp expense of
the process is tpo great to allow qf n}uch profit to the
manufacturer.
21. Washing,.—The preparation of brick-earth in the
neighbourhood of London is effected by processes quite
different from those jus|; described. For marl or malm
bricks, the earth is ground \o a pulp in a ^ash-mill, and
mixed with chalk previously ground to the consistence
of cream; this pulp, or, as it is technically called,
malm, is run off through a fine grating into pits prepared to receive it, and there left, until by evaporation
and settlement, it becomes of sufficient consistency tq
allow a man to walk upon it. I t is then soiled, i.e.
covered with sittings from domestic ashes, and left
through the winter to mellow. At the commencement
of the brickmaking season the whole is turned over,
and the ashes thoroughly incorporated with the earth
in the pugmill. In making common bricks, the whole
of the earth is not washed, but the unwashed clay is

ART OF MAKING BRICKS AND TILES*

25

heaped up on a prepared floor, and a proportion of
liquid malm poured over it, after which it is soiled in
the same way as for making malms.
These processes are well calculated to produce sound,
hard, and well-shaped bricks. The washing of the clay
effectually frees it from stones and hard lumps, whilst
the mixing of the chalk and clay in a fluid state ensures
the perfect homogeneousness of the mass, and enables
the lime to combine with the silica of the clay, which
would not be the case unless it were in a state of
minute division.
22. There are very few earths suitable in their natural
state for making cutters. They are therefore usually
made of washed earth mixed up with a proportion of
sand. Without the addition of sand the brick would
not bear rubbing, and it would be very difficult to bring
it to a smooth face.
23. I t maybe here observed that sufficient attention
is not generally paid to the preparation of brick-earth,
as it too frequently happens that the clay is dugjin'the
spring instead of the autumn, in which case the benefit
to be derived from the winter frosts is quite lost. The
use of rollers, to a certain extent, counterbalances this;,
but bricks made of clay that has been thoroughly
weathered are sounder and less liable to warp in the
kiln.
.
,
TEMPERING.

/,

',

,

24. The object of tempering is to bring the prepared
brick earth into a homogeneous past^fpr the ;:use of
the moulder.
The old-fashioned way of tempering was to turn the
clay over repeatedly with shovels, and to tread it over
by horses or men, until it acquired the requisite plasticity. This method is still practised in many country
c

26

RUDIMENTS OF T H E

yards; but where the demand for bricks is extensive,
machinery is usually employed, the clay being either
ground between rollers or pugged in a pugmill. This
latter process is also called grinding, and, therefore, in
making inquiries respecting the practice of particular
localities, the reader should be careful that he is not
misled by the same name being applied to processes
which are essentially different.
When rollers are used in the preliminary processes,
the labour of tempering is much reduced. Their use is,
however, most generally confined to the process of
tempering, which is then effected as follows :—The clay,
which has been left in heaps through the winter to
mellow, is turned over with wooden shovels (water
being added as required), and wheeled to the mill,
where it is crushed between the rollers, and falls on a
floor below them, where it is again turned over, and is
then ready for use.
When the clay is sufficiently mild and free from lime
and ironstone as not to require crushing, tempering by
spade labour and treading is generally adopted; but
in the districts where rollers are used, the brick-earths
are generally so indurated that a great proportion could
not be rendered fit for use by the ordinary processes.
The advantages and disadvantages of the use of rollers
are considered at some length in chap. iii. art. 4.
25. In making bricks for railway works, which has
been done lately to an almost incredible extent, contractors are generally little anxious as to the shape or
appearance of the article turned out of the kiln, provided it be sufficiently sound to pass the scrutiny of the
inspector or resident engineer. As the whole process
of railway brickmaking often occupies but a few weeks
from the first turning over of the clay to the laying of

ART OF MAKING BRICKS AND TILES.

27

the bricks in the work, the use of rollers in such cases
is very desirable, as a partial substitute for weathering.
On the line of the Nottingham and Grantham Railway
several millions of bricks have been made as follows :—
The clay is first turned over with the spade, and watered
and trodden by men or boys, who, at the same time,
pick out the stones. I t is then wheeled to the mill
and ground; after which it is turned over a second
time, and then passed at once to the moulding table.
26. Although in many country places, where the
demand for bricks is very small, tempering is still performed by treading and spade labour, the pugmiil is
very extensively used near London, and in most places
where the brick-earth is of mild quality, so as not to
require crushing, and the demand for bricks sufficiently
constant to make it worth while to erect machinery.
The pugmiil used near London is a wooden tub, in shape
an inverted frustrum of a cone, with an upright revolving
shaft passing through its centre, to which are keyed a
number of knives, which, by their motion, cut and
knead the clay, and force it gradually through the mill,
whence it issues in a thoroughly tempered state, fit for
the use of the* moulder. Some contend that the pugmill is no improvement on the old system of tempering
by manual labour; but, without entering into this question, there can be no doubt that it does its work very
thoroughly, and its use prevents the chance of the tempering being imperfectly performed through the negligence of the temperers. In the London brickfields the
process of tempering is conducted as follows:—The
malm, or maimed brick-earth, as the case may be, is
turned over with the spade, and the soil* (ashes) dug
* Soil, is. ashes, must not be confounded with soil, vegetable mould,
which is iii some places mixed with strong clay, to render it milder.

c 2

28

RUDIMENTS OF THE

into it, water being added as may be necessary. It is
then harrowed to the pugmill, and being thrown in at
the top, passes through the mill, and keeps continually
issuing at a hole in the bottom. As the clay issues
from the ejectment hole, it is cut into parallelopipedons
by a labourer, and, if not wanted for immediate use, is
piled up and covered with sacks to prevent it from
becoming too dry.
In Staffordshire steam power is used for driving both
rollers and pugmill, and the case of the latter is usually
a hollow cast-iron cylinder.
MOULDING.

27. A brick-mould is a kind of box without top or
bottom, and the process of moulding consists in dashing
the tempered clay into the mould with sufficient force
to make the clot completely fill it, after which the
superfluous clay is stricken with a strike, and the newlymade brick is either turned out on a drying floor to
harden, or on a board or pallet, on which it is wheeled
to the hack-ground. The first mode of working is
known as slop moulding, because the mould is dipped
in water, from time to time, to prevent the clay from
adhering to it. The second method may be distinguished
as pallet moulding; and in this process the mould is
not wetted, but sanded. These distinctions, however,
do not universally hold good, because in some places'
slop-moulded bricks are turned out on pallets.
28. These differences may, at first sight, appear
trivial, but they affect the whole economy of a brickwork. In slop moulding the raw bricks are shifted by
hand from the moulding table to the drying floor, from
the drying floor to the hovel or drying shed, and from

AUT OF MAKING BRICKS AND TILES.

29

the hovel to the kiln. It is therefore requisite that
the works should be laid out so as to make the distance
to which the bricks have to be carried the shortest possible. Accordingly,* the kiln is placed in a central
situation in a rectangular space, bounded on two or
more sides by the hovel, and the working floors are
formed round the outside of the latter.
In the process of slop moulding the newly-made brick
is carried, mould and all, by the moulder's boy to the
flat, or drying floor, on which it is carefully deposited;
and whilst this is being done, the moulder makes a
second brick in a second mould, the boy returning with
the first mould by the time the second brick is being
finished. As soon, therefore, as the floor becomes
filled for a certain distance from the moulding table, the
latter must be removed to a vacant spot, or the distance
to which the bricks must be carried would be too great
to allow of the boy's returning in time with the empty
mould.
29. In pallet moulding but one mould is used. Each
brick/as it is moulded, is turned out on a pallet, and
placed by a boy on a hack-barrow, which, when loaded,
is wheeled away to the hack-ground, where the bricks
are built up to dry in low walls called hacks. One
moulder will keep two wheelers constantly employed,
two barrows being always in work, whilst a third is
being loaded at the moulding stool. When placed on
the barrow, it is of little consequence (comparatively)
whether the bricks have to be wheeled 5 yards or 50;
and the distance from the moulding stool to the end of
the hacks is sometimes considerable.
30. The moulding table is simply a rough table, made
* There are, of course, some exceptions; but, where practicable, the
drying floors and hovel are placed close to the kilns.

30

RUDIMENTS OF T H E

in various ways in different parts of the country, but
the essential differences are, that for slop moulding the
table is furnished with a water trough, in which the
moulds are dipped after each time of using; whilst in
pallet moulding, for which the mould is usually sanded
and not wetted, the water trough is omitted, and a page
(see account of Brickmaking as practised in London) is
added, on which the bricks are placed preparatory to
their being shifted to the hack-barrow.
31. Brick moulds are made in a variety of ways.
Some are made of brass cast in four pieces and riveted
together; some are of sheet iron, cased with wood on
the two longest sides; and others again are made
entirely of wood, and the edges only plated with iron.
Drawings and detailed descriptions of each of these
constructions are given in the subsequent chapters. In
using wooden moulds the slop-moulding process is
almost necessary, as the brick would not leave the sides
of the mould unless it were very wet. Iron moulds are
sanded, but not wetted. Brass, or, as they are technically called, copper moulds, require neither sanding nor
wetting, do not rust, and are a great improvement on
the common wooden mould formerly in general use.
They, however, are expensive, and will not last long, as
the edges become worn down so fast that the bricks
made from the same mould at the beginning and end
of a season are of a different thickness, and cannot be
used together. This is a great defect, and a metal
mould which will not rust nor wear is still a great desideratum. I t is essential that the sides of the mould
should be sufficiently stiff not to spring when the clay
is dashed into it, and it is equally requisite that it
should not be made too heavy, or the taking-off boy
would not be able to carry it to the floor. A common

ART OF MAKING BRICKS AND TILES.

31

copper mould weighs about 4 lbs., and, with the wet
brick in it, about 12 lbs., and this weight should not
be exceeded.
32. There is a great difference in the quantity of
bricks turned out in a given time by the pallet moulding
and by the slop moulding processes. In slop moulding
10,000 per week is a high average^ whilst a London
moulder will turn out 36,000 and upwards in the same
period. This arises in a great measure from the circumstance that in pallet moulding the moulder is
assisted by a clot moulder, who prepares the clot for
dashing into the mould; whilst in slop moulding the
whole operation is conducted by the moulder alone.
33. In some places the operation of moulding partakes both of slop moulding and pallet moulding, the
bricks being turned out on pallets and harrowed to the
hack-ground, whilst the moulds are wetted as in the
ordinary process of slop moulding.
34. The substitution of machinery for manual labour
in the process of moulding has long been a favourite
subject for the exercise of mechanical talent; but
although a great number of inventions have been patented, there are very few of them that can be said to
be thoroughly successful. The actual cost of moulding
bears so small a proportion to the total cost of brickmaking, that in small brickworks the employment of
machinery would effect no ultimate saving, and, therefore, it is not to be expected that machinery will ever
be generally introduced for brick moulding. But in
works, situated near large towns, or in the execution of
large engineering works, the case is very different, and
a contractor who requires, say, 10,000,000 of bricks, to
be made in a limited time, for the construction of a
tunnel or a viaduct, can employ machinery with great

32

RUDIMENTS OF THE

advantage. A chapter on brickmaking machines will
be found in another part of this volume.
35. I t has been much discussed by practical men,
whether bricks moulded under great pressure are better
than those moulded in the ordinary way. They are of
denser texture, harder, smoother, heavier, and stronger
than common bricks. On the other hand, it is difficult
to dry them, because the surfaces become over-dried
and scale off before the evaporation from the centre is
completed. Their smoothness lessens their adhesion to
mortar; and their weight increases the cost of carriage,
and renders it impossible for a bricklayer to lay as
many in a given time as those of the ordinary weight.
On the whole, therefore, increased density may be considered as a disadvantage, although, for some purposes,
dense bricks are very valuable.
36. Mr. Prosser, of Birmingham, has introduced a
method of making bricks, tiles, and other articles by
machinery, in which no drying is requisite, the clay
being used in the state of a nearly dry powder. The
clay from which floor-tiles and tesserse are made is first
dried upon a slip-kiln,* as if for making pottery, then
ground to a fine powder, and in that state subjected to
heavy pressuref in strong metal moulds: by this means
the clay is reduced to one-third of its original thickness,
and retains sufficient moisture to give it cohesion. The
articles thus made can be handled at once, and carried
direct to the kiln. In some experiments tried for ascertaining the resistance of bricks and tiles thus made to
* The slip-Mln is a stone trough bottomed with fire tiles, under which
runs a furnace flue. It is used in the manufacture of pottery for evaporating the excess of water in. the slip, or liquid mixture of clay and ground
flints, which is thus brought into the state of paste.
f It is a common but an erroneous notion, that articles made by Mr.
Prosser's process are denser than similar articles made in the common
way: the reverse is the fact.

ART OF MAKING BRICKS AND TILES.

33

a crushing force, a 9-inch brick sustained a pressure of
90 tons without injury.
37. Mr. Prosser's method offers great advantages for
the making of ornamental bricks for cornices, basreliefs, floor-tiles, tesselated pavements, &c. Screw
presses are used to a considerable extent for pressingbricks when partially dry, to improve their shape and
to give them a smooth face; but we have in many instances found pressed bricks to scale on exposure to
frost, and much prefer dressing the raw brick with a
beater, as described in chap. iii. art. 34.
38. The great practical difficulty in making moulded
bricks for ornamental work is the warping and twisting
to which all clay ware is subject more or less in the
process of burning. This difficulty is especially felt in
making large articles, as wall copings, &c. In moulding
goods of this kind it is usual to make perforations
through the mass, to admit air to the inside, without
which precaution it would be impossible to dry them
thoroughly; for, although the outside would become
hard, the inside would remain moist, and, on being
subjected to the heat of the kiln, the steam would crack
and burst the whole.
The Brighton Viaduct, on the Lewes and Hastings
Railway, has a massive white brick * dentil cornice, the
bricks for which were made in Suffolk after several
unsuccessful attempts to make bricks of still larger size.
The thickness of the bricks first proposed presenting an
insurmountable obstacle to their being properly dried,
their dimensions were reduced, and large perforations
were made in each brick to reduce its weight, and to
enable it to be more thoroughly and uniformly dried;
* Brick was preferred to stone on account of the expense of the latter
material*

c 3

34

RUDIMENTS OF THE

and by adopting this plan the design was successfully
carried into execution.
39. The usual form of a brick is a parallelopipedon,
about 9 in. long, 4J in» broad, and 3 in. thick, the exact
size varying with the contraction of the clay. The
thickness need not bear any definite proportion to the
length and breadth, but these last dimensions require
nice adjustment, as the length should exceed twice the
breadth by the thickness of a mortar joint.
; 40. Bricks are made of a variety of shapes for particular purposes, as enumerated in art. 60, chap. iii. The
manufacture of these articles is principally carried on in
the country, the brickfields in the vicinity of the metropolis supplying nothing but the common building brick.
41. A point of some little importance may be here
adverted, to, viz., is any advantage gained by forming a
hollow in the bed of the brick to form a key for the
mortar ? There are various opinions on this point; but
we think it may be laid down as a principle, that if it is
useful on one side it will be still better on both, so as to
form a double key for the mortar. In London, the
brick mould is placed on a stock board, which is made
to fit the bottom of the mould; and the relative positions
of the two being kept the same, no difficulty exists in
forming a hollow on the bottom of the brick, this being
effected by a kick fastened on the stock board. But
this could not be done on the upper side, which is
stricken level. In slop moulding, the mould is simply
laid on the moulding stool, or on a moulding board
much larger than the mould, and both sides of the brick
are flush with the edges of the mould, no hollow being
left, unless the moulder think fit to make one by scoring
the brick with his fingers, which is sometimes done.
When machinery is used in moulding, it is equally easy

ART OF MAKING BRICKS AND TILES.

35

to stamp the top and the bottom of the brick; and we
have seen, at the Butterly Ironworks, in Derbyshire,
excellent machine-made bricks of this kind made in
the neighbourhood.
42. Amongst the many inventions connected with
brickmaking which have been from time to time brought
before the public, ventilating bricks deserve attention,
from the facilities they afford for warming and ventilating buildings.
The annexed figures show the form of the bricks a^nd
the way in which they are used.
Fig. 1.

Fig. 2.

Fig. 3.

Fig. 1 is a representation of a 9-in. wall, built with
the ventilating bricks, with one common brick used at
the angle of each course.
Fig. 2 is a representation of a 14-in. wall; the half
ventilating brick, being used alternately in the courses,
forms a perfect and effectual bond.
Fig. 3 is an isometrical drawing showing the ventilating spaces.
DRYING.

43. The operation of drying the green bricks requires
great care and attention, as much depends upon the

36

RUDIMENTS OF THE

manner in which they are got into the kiln. The great
point to be aimed at is to protect them against sun,
wind, rain, and frost, and to allow each brick to dry
uniformly from the face to the heart.
Slop-moulded bricks are usually dried on flats or
drying floors, where they remain from one day to five or
six, according to the state of the weather. When spread
out on the floor they are sprinkled with sand, which
absorbs superfluous moisture, and renders them less
liable to be cracked by the sun's rays. After remaining
on the floors until sufficiently hard to handle without
injury, they are built up into hacks under cover, where
they remain from one to three weeks, until ready for the
kiln. In wet weather they are spread out on the floor
of the drying shed, and great care must then be taken
to avoid drafts, which would cause the bricks to dry
faster on one side than the other. To prevent this,
boards set edgeways are placed all round the shed to
check the currents of air.
The quantity of ground required for drying bricks in
this manner is comparatively small, as they remain on
the floors but a short time, and occupy little space when
hacked in the hovels. The produce of a single moulding
stool by the slop-moulding process seldom exceeds
10,000 per week, and the area occupied by each stool is,
therefore, small in proportion. Half an acre for each
kiln may be considered ample allowance for the working
floor and hovel.
44. In places where brickmaking is conducted on a
large scale, drying sheds are dispensed with, and the
hacks are usually built in the open air, and protected
from wet, frost, and excessive - heat, by straw, reeds,
matting, canvas screens, or tarpaulins; all of which we
have seen used in different places.

ART OF MAKING BRICKS AND TILES.

37

45. Bricks intended to be clamp burnt are not dried
on flats, but are hacked at once on leaving the moulding
stool, and remain in the hacks much longer than bricks
intended to be kilned. This is rendered necessary by
the diflPerence between clamping and kilning. In the
latter mode of burning, the heat can be regulated to
great nicety, and if the green bricks, when first placed
in the kiln, be not thoroughly dried, a gentle heat is
applied until this is effected. In clamping, however,
the full heat is attained almost immediately, and,
therefore, the bricks must be thoroughly dried, or they
would fly to pieces. In the neighbourhood of London
a good moulder, with his assistants, will turn out from
30,000 to 40,000 bricks per week, and the clamps
contain from 60,000 to 120,000 bricks and upwards.
From these combined causes, the area occupied by
each stool is greater than in making slop-moulded
bricks. In Mr. Bennett's brick-ground at Cowley, ten
stools occupy twenty acres.
46. At the risk of wearying the patience of the
reader, we recapitulate the leading points on which
depends the difference of area required for each moulding stool in mating:—
Slop-moulded bricks, hacked tinder London pallet-moulded sand stocks,
cover, and burnt in kilns.
burnt in clamps.
Dried one dav on flats . . .
Closely stacked in hacks 17)
courses high, placed close
together undercover . . .
&
'
Kemain production per stool, I
Rate of in shed 10 to 16 days "
about 10,000 weekly . . . J
T
Iiln holds about 30,000 bricks, ]
and may be fired once in 10 I
days
* . .)

1st

Hacked at once.
f Brkks loosely stacked in hacks,
2nd J 8 ™ ™ high and S tacks
| f l d e > ™lfll 9 , f t - s P a c e s b e '
l tween the hacks.
_
3rd f A gang will turn out 30,000 to
.., Remain in hacks 3 to 6 weeks,
j 40,000 per week.
( Clamp contains 60,000 to
5th \
120,000 bricks, and burns
[ from 2 to 6 weeks.

47. I t is scarcely necessary to observe that different

OO

BTJDIMENTS OF THE

clays require different treatment, according to their
composition, some bricks bearing exposure to sun and
rain without injury, whilst others require to be carefully
covered up to keep them from cracking under similar
circumstances. [See Appendix.]
Superior qualities of bricks are generally dressed with
a beater when half dry, to correct any twisting or
warping which may have taken place during the first
stage of drying.
BURNING.

48. Bricks are burnt in clamps and in kilns. The
latter is the common method, the former being only
employed in burning bricks made with ashes^or coaldust. It should be observed, however, that the~name of
clamp is applied also to a pile of bricks arranged for
burning in the ordinary way, and covered with a
temporary casing of burnt brick to retain the heat; but
this must not be confounded with close-clamping as
practised in the neighbourhood of London.
49. The peculiarity of clamp burning is that each
brick contains in itself the fuel necessary for its vitrification ; the breeze or cinders serving only to ignite the
lower tiers of bricks, from which the heat gradually
spreads over the whole of the clamp. No spaces are
left between the bricks, which are closely stacked, that
the heat to which they are exposed may be as uniform
as possible. It is unnecessary here to go into the
details of clamping, as they are very fully given in
the account of London Brickmaking. [See also Appendix.]
50. A kiln is a chamber in which the green bricks
are loosely stacked, with spaces between them for the
passage of the heat; and baked by fires placed either

ART OF MAKING BRICKS AND TILES.

39

in arched furnaces under the floor of the kiln, or in fire
holes formed in the side walls.
There are many ways of constructing kilns, and
scarcely any two are exactly alike; but they may be
divided into three classes:—
1st. The common rectangular kiln with fire-holes in
the side walls. This is formed by building four walls
enclosing a rectangular space, with a narrow doorway
at each end, and narrow-arched openings in the side
walls exactly opposite to each other. The bricks are
introduced through the doorways, and loosely stacked
with considerable art, the courses being crossed in a
curious manner, so as to leave continuous openings
from top to bottom of the pile to distribute the heat.
In the lower part of the kiln narrow flues are left, about
8 in. wide and about 2 ft. or 3 ft. high, connecting the
fire-holes in the side walls. The kilns having been
filled, the doorways are bricked up and plastered with
clay to prevent the ingress of cold air; the top of the
kiln is covered with old bricks, earth, or boards, to
retain the heat, and the firing is carried on by burning
coal in the fire-holes. A low shed is generally erected
on each side of the kiln to protect the fuel and fireman
from the weather, and to prevent the wind from urging
the fires. The details of the management of a kiln are
given in another place, and need not'be here repeated.
This kind of kiln is he simplest that can well be
adopted, and is in use in Holland at the present day.
It is the kiln in common use through the Midland
districts.
2nd. The rectangular kiln with arched furnaces.
This consists also of a rectangular chamber; but differs
"from the first in having two arched furnaces running
under the floor the whole length of the kiln, the furnace

40

RUDIMENTS OF T H E

doors being at one end. The floor of the kiln is formed
like lattice-work, with numerous openings from the
furnaces below, through which the heat ascends. The
top of the kiln is covered by a moveable wooden roof,
to retain the heat, and to protect the burning bricks
from wind and rain. These kilns are used in the east
of England.
3rd. The circular kiln or cupola. This is domed over
at the top, whence its name is derived. The fire-holes
are merely openings left in the thickness of the wall,
and are protected from the wind by a wall built round
the kiln at a sufficient distance to allow the fireman
room to tend the fires. These cupolas are used in Staffordshire and the neighbourhood, and the heat employed
in them is very great. Drawings of a cupola are given
in chap, iv., with an account of the manner in which
the firing is conducted, and therefore it is unnecessary
to enter here upon any of these details.
51. The usual method of placing bricks in the kiln is
to cross them, leaving spaces for the passage of the heat,
but there are objections to this, as many bricks show
a different colour, where they have been most exposed
to the heat. Thus in,many parts of the country, the
bricks exhibit a diagonal stripe of a lighter tint than
the body of the brick, which shows the portion that
has been most exposed. In burning bricks that require
to be of even colour, this is guarded against by placing
them exactly on each other.
On first lighting a kiln the heat is got up gently, that
the moisture in the bricks may be gradually evaporated.
"When the bricks are thoroughly dried, which is
known by the steam ceasing to rise, the fires are made
fiercer, and the top of the kiln is covered up with
boards, turf, old bricks, or soil, to retain the heat. As

ART OF MAKING BRICKS AND TILES.

41

the heat increases, the mouths of the kiln are stopped
to check the draft, and when the burning is completed,
they are plastered over to exclude the air, and the fires
are allowed to go out. After this the kiln is, or should
be, allowed to cool very gradually, as the soundness of
the bricks is much injured by opening the kiln too
soon.
Pit coal is the fuel commonly used, and the quantity
required is about half a ton per 1,000 bricks; but much
depends on the quality of the coal, the construction of
the kiln, and the skill with which the bricks are stacked.
Wood is sometimes used as fuel in the preliminary
stage of firing, but not to a great extent. In a letter
received on the management of the Suffolk kilns, the
writer says, " The usual mode of firing bricks in Suffolk
is in a kiln. The one near me, belonging to a friend of
mine, is constructed to hold 40,000; it is about 20 ft.
long and 15 ft. broad, and is built upon two arched
furnaces that run through with openings to admit the
heat up. The bricks are placed in the usual way for
burning, by crossing so as to admit the heat equally
through, when the whole mass becomes red hot: the
first three or four days, wood is burnt in what is called
the process of annealing; with this they do not keep up
a fierce fire. After this from 12 to 14 tons of coal are
consumed in finishing the burning. Private individuals
sometimes make and clamp 20,000 or 30,000 without a
kiln; then there is great waste, and the bricks are not
so well burnt.
52. In the preceding pages we have briefly sketched
the operations of brickmaking, and the principles on
which they depend. In the following chapters the
reader will find these operations described in detail, as
practised in different parts of the country; it need

42

RUDIMENTS OF T H E

hardly be said that the illustrations might be greatly
extended, as there are scarcely two counties in England
in which the processes are exactly similar, but this
would lead us far beyond the limits of a Rudimentary
Treatise, and enough is given to show the student the
interest of the subject, and to enable him to think and
examine for himself. If he be induced to do this from
the perusal of these pages, the aim of this little volume
will have been completely fulfilled.
II.

TILES.

53. The manufacture of tiles is very similar to that
of bricks, the principal differences arising from the thinness of the ware, which requires the clay to be purer
and stronger, and renders it necessary to conduct the
whole of the processes more carefully than in making
bricks.
54. Tiles are of three classes, viz., paving tiles, roofing tiles, and drain tiles.
Paving tiles may be considered simply as thin bricks,
and require no especial notice.
'
Roofing tiles are of two kinds: pantiles, which are of
a curved shape, and plaintiles, which are flat, the latter
being often made of ornamental shapes so as to form
elegant patterns when laid on a roof.
Pantiles are moulded flat, and afterwards bent into
their required form on a mould. Plain tiles were
formerly made with holes in them for the reception of
the tile-pins, by which they were hung on the laths;
but the common method is now to turn down a couple
of nibs at the head of the tile, which answer the same
purpose.
Besides pantiles and plaintiles, hip, ridge, and

ART OF MAKING BRICKS AND TILES.

43

valley tiles, come under the denomination of roofing
tiles; these are moulded flat, and afterwards bent on a
mould, as in making pantiles.
Draining tiles belong to the coarsest class of earthenware. They are of various shapes, and are made in
various ways. Some are moulded flat, and afterwards
bent round a wooden core to the proper shape. Others
are made at once of a curved form, by forcing the clay
through a mould by mechanical means. Tile-making
machines are now almost universally superseding manual
labour in this manufacture, and many machines of
various degrees of merit have been patented during the
last few years.
55. Besides the above articles, the business of a tilery
includes the manufacture of tiles for malting floors,
chimney-pots, tubular drains, and other articles of
pottery requiring the lathe for their formation. We do
not, however, propose now to enter upon the potter's
art, which, indeed, would require an entire volume, but
shall confine ourselves to the description of the manufacture of roofing tiles as made in Staffordshire, and at
the London tileries, adding a few words on the making
of tesserae and ornamental tiles as practised by Messrs.
Minton/of Stoke-upon-Trent.
56. In the country it is common to burn bricks* and
tiles together, and as, in most places, the demand for
bricks is not great, except in the immediate vicinity of
large towns, where the demand is more constant, the
manufacturer generally only makes so many bricks as
are required to fill up the kiln.
Where there is a great and constant demand for
bricks and tiles, their manufacture is carried on sepa* In some places bricks and lime are burnt together.

44

RUDIMENTS OF T H E

rately, and tiles are burnt in a large conical building,
called a dome, which encloses a kiln with arched furnaces. There are many of these in the neighbourhood
of London, and, as we have described them very fully in
the chapter on London Tileries, we need say nothing
further here on this subject.
57. The manufacture of draining tiles is one which
daily assumes greater importance on account of the
attention bestowed on agriculture, and the growing
appreciation of the importance of thorough drainage.
Any discussion on the best forms of draining tiles, or
the most advantageous methods of using them, would,
however, be out of place in this volume. Neither need
we say much on the practical details of the manufacture,
as it is exceedingly simple, and as regards the preparation of the clay, and the processes of drying and burning,
is precisely similar to the other branches of tile-making.
With regard to the process of moulding, there is little
doubt but that hand moulding will soon be entirely
superseded by machinery; and the discussion of the
merits of the numerous excellent tile-making machines
now offered to the public, although of great interest to
those engaged in the manufacture, would be unsuited to
the pages of a rudimentary work, even were it practicable to give the engravings which would be necessary
to enable the reader to understand their comparative
advantages or defects.* A few words on the principal
features of the manufacture of drain tiles are, however,
required to enable the reader to appreciate its peculiar
character.
58. Bricks, paving tiles, and roofing tiles, are little
required, and seldom manufactured, except in the neigh* A few details will be found in the chapter on Brickmaldng by
Machinery.

ART OF MAKING BRICKS AND T I L E S .

45

bourhood of towns or of large villages, where the demand
is likely to be sufficiently constant to warrant the
erection of kilns, drying sheds, and other appurtenances
of a well-mounted brickwork. If a cottage is to be
rebuilt, a barn tiled, or it may be once in twenty or
thirty years a new farm steading erected in a rural district, it is generally cheaper to incur the expense of
carting a few thousand bricks or tiles than to erect the
plant necessary for making these articles on the spot.
But with drain tiles the case is reversed. They are
most wanted precisely in situations where a brick-yard
would be an unprofitable speculation, viz., in the open
country, and often in places where the cost of carriage
from the nearest brick-yard would virtually amount to
a prohibition in their use, if they cannot be made on
the spot, and that at a cheap rate. What is wanted,
therefore, is a good and cheap method of making drain
tiles without much plant, and without erecting an expensive kiln, as the works will not be required after sufficient
tiles have been made to supply the immediate neighbourhood, and therefore it would not be worth while to incur
the expense of permanent erections. The making drain
tiles a home manufacture is, therefore, a subject which
has much engaged the attention of agriculturists during
the last few years, and it gives us great pleasure to
be enabled to give engravings of a very simple and
effective tile-kiln erected by Mr. Law Hodges, in his
brick-yard, and described in the Journal of the Royal
Agricultural Society, vol. v., part 2, from which publication we have extracted so much as relates to the
description of this kiln, and the cost of making drain
tiles in the manner recommended by him. [See Appendix.]
59. We have already extended this sketch of the

46

RUDIMENTS OF THE

general principles and practice of brick and tile making
beyond its proper limits, and must therefore pass on to
the practical illustrations of our subject.
The chapter " On the Manufacture of Bricks and
Tiles in Holland" is reprinted from the third volume of
Weale's " Quarterly Papers on Engineering/' and will
be read with interest on account of the great similarity
of the English and Dutch processes.
The account of brickmaking, as practised at Nottingham and the Midland counties, was written from
personal examination of brickworks in the vicinity of
Nottingham, and in the counties of Derby, Leicester,
and Lincoln, and has been carefully revised by a gentleman long connected with one of the principal brickworks near Nottingham.
The paper " On Brickmaking, as practised in the
Staffordshire Potteries," was contributed to this volume
by Mr. R. Prosser, of Birmingham, whose name is a
sufficient guarantee for the value of the information
therein contained. The details for this paper were collected by Mr. Prosser's assistant, Mr. John Turley, of
Stoke; and the valuable analyses of brick-earths were
made for Mr. Prosser by Mr. P. C. Wrightson, of
Birmingham, at a considerable expense.
The description of brickmaking in the vicinity of
London has been drawn up with great care, and is the
first illustrated account that has yet appeared of the
manufacture of clamp bricks. The drawings accompanying this paper, and that on the London Tileries,
are from the pencil of Mr. B. P. Stockman.
Professional engagements preventing a personal examination of the processes employed in brick and tilemaking in the vicinity of the metropolis, Mr. Stockman
kindly undertook this task, and to his persevering

AET OP MAKING BRICKS AND TILES.

47

energy and talent we are indebted for a great mass of
practical details embodied in these two chapters.
Lastly, in the Appendix are inserted various particulars relative to brickmaking which could not have
been introduced in any other part of the volume without interrupting the continuity of the text.
It should be noted that the various prices and estimates given in the following pages, refer to the time at
which the descriptions were given. They are, of course,
subject to later modifications.

CHAPTER I I .
ON THE MANUFACTURE OE BRICKS AND TILES IN
HOLLAND.

B Y HYDE CLARKE,

C.E.

I.—BRICKS.

THE Dutch make a most extensive use of bricks, of
which they have several kinds. Not only are bricks
used for ordinary building purposes, and for furnaces,
but also in great quantities for foot pavements, towing^
paths, streets, and high roads. It may be observed,
that they have of late been used very effectively in this
country for the pavement of railway stations. The
paving bricks, or Dutch clinkers, are the hardest sort,
and are principally manufactured at Moor, a smal village about two miles from Gouda, in South Holland.
The brick-fields are on the banks of the river Yssel,
from which the chief material is derived, being no other
than the slime deposited by the river on its shores, and
at the bottom. The slime of the Haarlem Meer is also
extensively used for this purpose, as most travellers
know. This is collected in boats, by men, with long

48

RUDIMENTS OF THE

poles having a cutting circle of iron at the end, and a
bag-net, with which they lug up the slime. The sand
is also obtained by boatmen from the banks of the river
Maes. It is of a fine texture, and grayish colour. The
hard bricks are made with a mixture of this slime and
sand, but in what proportions I am not informed.
River sand is recognised as on6 of the best materials
for bricks, and is used by the London brickmakers, who
obtain it from the bottom of the Thames, near Woolwich, where it is raised into boats used for the purpose.
For what are called in France, Flemish bricks, and
which are manufactured in France, Flanders, and on
the corresponding Belgian frontier, river sand is preferred, and is obliged to be obtained from the Scheldt.
At Ghent, and lower down, a considerable traffic is
carried on in the supply of this material. The quantity
used there is about one cubic foot of sand per cubic
yard.
The slime and sand, being mixed, are well kneaded
together with the feet, and particular attention is paid
to this part of the process. The mixture is then deposited in heaps. The mode of moulding and drying is
similar to that used elsewhere. Paving bricks are
generally about 6 in. long, 4 in. broad, and If in. thick.
Dutch clinks made in England are 6 in. long, 3 in.
broad, and 1 in. thick.
The house bricks and the tiles are made for the most
part at Utrecht, in the province of the same name, from
brick earth found in the neighbourhood. House bricks
are about 9\ in. long, 4 | in. wide, and nearly 2 in. thick.
II.—BRICK-KILNS.

The kilns are built of different sizes, but generally
on the same plan. Sometimes they will take as many

ART OF MAKING BRICKS AND T I L E S .

49

as 1,200,000 bricks. A kiln for burning 400,000 bricks
at once is represented in the " Memoirs of the Academy
of Sciences of Prance." It is a square of about 33 ft. or
35 ft. long by 28 ft, or 30 ft. wide, closed in with four
walls of brick, 6 ft. thick at the base, and which slope
upwards outside to their extreme height, which is about
18 ft. Some slope also slightly inwards, but in a different direction. Different plans are nevertheless
adopted with regard to the form of the external walls,
the great object being, however, to concentrate the heat
as much as possible. In the walls, holes are left for
six flue-holes, and sometimes for eight or ten or twelve.
In one of the walls, ih the breadth of the kiln, an
arched doorway is made, about 6 ft. wide and 12 ft.
high, by which the bricks are brought into the kiln.
The arrangements as to the doorway are also subject to
variation. The interior of the kiln is paved with the
bricks, so as to present a level base. The walls are laid
with mortar of the same earth from which the bricks
are made, and with which they are also plastered inside ; yet> notwithstanding the strength with which they
are built, the great power of the kiln fire sometimes
cracks them. The kilns, I would observe, are not usually
covered in, but some of those for baking building-bricks
have roofs made of planks, and without tiles, to shelter
them from the wind and rain. Others are provided
with rush mats, which are changed according to the
side on which the wind blows. The matting also serves
for protecting the bricks against the rain, whilst the
kiln is being built up. A shed, or hangar, is put up on
each side of the kiln, in order to contain the peat turf,
or to shelter the fire-tender, and to preserve the fires
against the effects of wind. Such being the practice
with regard to roofing, when the bricks are put into the
D

50

RUDIMENTS OF THE

kiln, a layer, or sometimes two layers, of burnt bricks
is placed on the floor, laid lengthwise, about threequarters of an inch from each other, and so as to slope
a little from the parallel of the walls, that they may
the better support the upper rows, which are always
laid parallel to the walls. This layer is covered with
old rush mats, on which are arranged the dried bricks,
which are laid without intervals between them. I t is
said that the mats serve to prevent the humidity of the
soil from penetrating to the bricks while the kiln is
being filled, which generally takes from about three
weeks to a month. This row of burnt bricks is so
placed as to leave channels or flues of communication
with corresponding openings in the kiln walls. Six
layers of dried bricks having been put down, the next
three rows are made to jut over, so as to shut up the
channels or flues. The layers are thus carried up to
about forty-five in number, the last two being of burnt
bricks, though in some kilns four layers of burnt bricks
are used for closing in* The. crevices are secured with
brick earth or clay, on which sand is put; the door of
the kiln is then closed with one or two thicknesses of
burnt brick, then an interval of about 10 in. or 12 in.
filled in with sand, and this secured with walling, and
by a wooden strut. The object of the sand is to prevent
any of the heat from escaping through the crevices.
It is to be remarked that, in laying the bricks in the
kiln, as they are laid down, a cloth is put over them
and under the feet of the workmen, so as to prevent any
of the sand which might fall off, from getting down
and blocking up the interval or interstice which naturally remains between each brick, and so interrupting
the passage of the flame, and causing an unequal heat
or combustion in the kiln.
The kiln being filled, a sufficient quantity of peat turf

ART OF MAKING BRICKS AND TILES.

51

is introduced into the flues, of which one end is closed
up with burnt bricks, and the turf is set fire to. The
turf used is from Friesland, which is reckoned better
than Holland turf, being lighter, less compact, and less
sarthy, composed of thicker roots and plants, burning
quicker and with plenty of flame, and leaving no ash.
The general time in Holland during which the supply
of turf by the flues is kept up, is for about four-andtwenty hours, taking care at first to obtain a gradual
beat, and supplying fresh turf about every two hours.
The fireman, by practice, throws the turfs in through
the small fire openings, and as far in as he judges
necessary. "When one side has thus been heated, the
flue openings are closed, and the other ends opened for
four-and-twenty hours, and supplied with fuel; and this
alternate process is kept up for about three or four
weeks, the time necessary to burn large bricks. I n
some kilns, however, the fire is kept up for five or six
weeks, depending upon their size and the state of the
weather. A fortnight or three weeks is, however,
sometimes enough for the clinkers.
The burning having been concluded, about three
weeks are allowed for cooling. It generally happens
that the mass of brick sinks in in some places, arising
partly from the diminution of volume produced by
burning, and partly from the melting of some of the
bricks which have been exposed to too great heat.
The quality of the bricks depends upon the degree
of burning to which they have been subjected. Those
from about a third from the middle of the top of the
kiln, or near the centre, are black, very sonorous, compact and well shaped, breaking with a vitrified fracture,
These are generally employed for cellars, reservoirs,
and cisterns, and are most esteemed.
D 2

52

RUDIMENTS OF THE

III.—TILES.

The tiles manufactured in Holland are flat, hollow, S
shaped, or with a square opening in the middle to let
in a pane of glass, being much used for lighting lofts
and garrets all over the Low Countries. They are
either red, grey, or blue, or glazed on one side only.
The flat paving tiles are about 8-| in. square by 1 in.
thick; they are used principally for cisterns and for
bakers' ovens. The clay for tiles, it is to be noted, is
in all cases more carefully prepared than that for bricks,
being ground up wet in a pugmill or tub, with a shaft
carrying half a dozen blades. By this means, roots,
grass, &c, are got rid of. The clay comes out of the
pugmill of the consistence of potters' clay, and is kept
under a shed, where it is kneaded by women, with their
hands, to the rough form of a tile, on a table dusted
with sand. These pieces are carried off to the moulders,
who are two in number, a rough moulder and a finisher.
The tiles are then dried under sheds, and afterwards in
the sun. With regard to the flat paving tiles, they are
at first rough-moulded about an inch larger than the
subsequent size, and a little thicker, and then laid out
to dry under a shed, until such time as the thumb can
hardly make an impression on them. They are then
taken to a finishing-moulder, who, on a table quite level
and slightly dusted with sand, lays one of the tiles, and
strikes it twice or thrice with a rammer of wood larger
than the tile, so as to compress it. He then takes a
mould of wood, strengthened with iron and with iron
cutting edges, and puts it on the tile which he cuts to
the size. The mould is of course wetted each time it is
used. The tiles are then regularly dried. In Switzerand ancl Alsace an iron mould is used.

ART OF MAKING BRICKS AND TILES.

53

IV.—TILE-KILNS.

The tile-kiln is generally within a building, and about
16 ft. long (in ordinary dimension), 10 ft. wide, and
10 ft. high. The walls are from 4^ ft. to 5 ft. thick,
secured outside with great beams, and so secured together as to form a square frame. Some of the largest
of them are pierced with four flue-holes, as in brickkilns ; but the flues are formed by a series of brick
arches, about %\ ft. wide by 16 in. high. The opening
of the flue-hole is about 10 in. by 8 or 9 in. high. On
their upper surface, these series of arches form a kind
of grating, on which the tiles are laid. The kiln is
cohered in at top with a brick arch, pierced with holes
of different sizes. The kilns are charged from an opening which is constructed in o.ne of the side walls, which
opening is, of course, during the burning, blocked up
and well secured. The fuel used is turf, as in the brickkilns, and the fire is kept up for forty hours together,
which is considered enough for the burning. Three
days are then allowed for cooling, and they are afterwards taken out of the kiln. Those tiles which are to
be made of a greyish colour are thus treated. It having
been ascertained that the tiles are burnt enough, and
while still red hot, a quantity of small fagots of green
alder with the leaves on is introduced into each flue.
The flue-holes are then well secured, and the holes in
the roof each stopped with a paving tile, and the whole
surface is covered with 4 in. or 5 in. of sand, on which
a quantity of water is thrown,, to prevent the smoke
from escaping anywhere. I t is this smoke which
gives the grey colour to the tiles, both internally and
externally. The kiln is then left closed for a week, when
the sand is taken off the top, the door and. roof-holes

54

RUDIMENTS OF THE

are opened, as also the flue-holes, and the charcoal
produced by the fagots taken out. Forty-eight hours
after, the kiln is cool enough to allow of the tiles being
taken out, and the kiln charged again. "Whenever any
of the tiles are to be glazed, they are varnished after
they are baked; the glaze being put on, the tiles are
put in a potter's oven till the composition begins to
run. The glaze is generally made from what are called
lead ashes, being lead melted and stirred with a ladle
till it is reduced to ashes or dross, which is then sifted,
and the refuse ground on a stone and resifted. This
is mixed with pounded calcined flints. A glaze of
manganese is also sometimes employed, which gives a
smoke-brown colour. Iron filings produce black;
copper slag, green; smalt, blue. The tile being wetted,
the composition is laid on from a sieve.
The manufacture of tiles, as already observed, is
principally carried on near Utrecht, in the province of
Holland, which, like most of the great cities of Holland, has facilities for the transportation of its produce
by water communication all over the country.
Qouda is a great seat of the pottery and tobacco-pipe
manufactures, of which formerly Holland had a virtual
monopoly, with regard to foreign trade, exporting largely
Delft ware, Dutch porcelain, tobacco-pipes, bricks,
Flanders' bricks, painted tiles, and paving tiles. The
manufacture of painted tiles, for the decoration of the
old fireplaces, was very extensive; and an infinite variety
of designs, principally on Scripture subjects, employed
many humble artists. This, however, is almost of the
past. The manufacture of tobacco-pipes was another
great business, suitable to the consumption of tobacco
by the Netherlanders. Gouda alone had, at one
time, as many as 300 establishments for the pro-

ART OF MAKING BRICKS AND TILES.

55

duction of this article of trade. The manufacture of
tobacco-pipes is still a large manufacture in England,
much more considerable than is generally supposed;
while manufactures of bricks and porcelain constitute a
staple means of employment for many thousands of
our population.
A great part of these descriptions, it will be seen,
strictly apply to our own practice, and are trite enough
and trivial enough ; but in matters of this kind, there
is nothing lost by being too minute, and it is always
safe. In the present case, it is worth knowing these
things, for the sake of knowing that there is no
difference.

CHAPTER I I I
BRICKMAKING AS PRACTISED AT NOTTINGHAM.

1. The mode of making bricks at Nottingham and
the neighbourhood presents several peculiarities, of which
the principal are :—
1st. The use of rollers for crushing the brick-earth.
2nd. The use of copper moulds.
3rd. The hacking of the bricks under cover.
2. The use of copper moulds is not confined to the
immediate neighbourhood of Nottingham, but has been
for some years gradually extending to other districts,
and will probably, sooner or later, become general
throughout the country for the manufacture of superior
qualities of bricks.
3. I t may be proper here to say a few words on the
object of grinding the clay, so generally practised
throughout Staffordshire, Derbyshire, Nottinghamshire,
and Lincolnshire, and probably in many other places.

56

RUDIMENTS OF T H E

In many brickworks the earth used is not pure clay,
but a very hard marl, which cannot be brought into a
state of plasticity by the ordinary processes of weathering and tempering without bestowing upon it more
time and labour than would be repaid by the value of
the manufactured article. The expedient of grinding
is, therefore, resorted to, which reduces the earth to any
state of fineness required, according to the number of
sets of rollers used, and the gauge to which they are
worked, all hard ]umps and pieces of limestone,* which
would otherwise have to be picked out by hand, being
crushed to powder, so as to be comparatively harmless.
4. The advantages and disadvantages of the use of
rollers may be thus briefly stated,—
1st. A great deal of valuable material is used which
could not be made available for brickmaking by
the ordinary processes.
2nd. The process of grinding, if properly conducted, greatly assists the operations of the
temperer by bringing the earth into a fine state,
quite free from hard lumps.
On the other hand :
The facilities afforded by the use of rollers for working
tip everything that is not too hard to be crushed by
them, induce many brickmakers to make bricks without
proper regard to the nature of the material. A common
practice is to work the rollers to a wide gauge, so that
comparatively large pieces of limestone are suffered to
pass through without being crushed by them. Where
this has been the case, it need hardly be said that the
bricks are worthless. They may appear sound, and
* It may be necessary to explain, that all pebbles and hard stones must
be picked out by hand before grinding; where the brick earth used is
much mixed with gravel, the only resource is the use of the wash mill.

ART OF MAKING BRICKS AND TILES.

57

may have a tolerable face, but rain and frost soon destroy
them, and, in situations where they are exposed to the
weather, they will become completely perished in a very
few years.
5. The following description of the mode of making
bricks at Nottingham will apply pretty faithfully to the
practice of the brick-yards for many miles round. I t
will, of course, be understood that in no two yards is
the manufacture carried on in exactly the same way;
there being differences in the designs of the kilns, the
arrangement of the buildings, and other points of
detail, which may be regulated by local circumstances,
or which, from the absence of any guiding principle,
may be left to chance; the general features, however,
are the same in all cases.

6. Brick-earth.—The brickmakers of Nottingham
and its immediate vicinity derive their supplies of brickearth from the strata of red marl overlying the red
sandstone on which the town is built, and which in its
turn rests on the coal-measures, which make their
appearance at a short distance to the west of the town.
The banks of the river Trent present many good
sections of these strata, as at the junction of the rivers
Trent and Soar; where they are pierced by the Red
Hill tunnel, on the line of the Midland Railway; and
at Radcliff-on-Trent, where they form picturesque cliffs
of a red colour covered with hanging wood; and they
are exposed to view in many places in the immediate
vicinity of Nottingham, as in the cutting for the old
road over Ruddington Hill, in the Colwick cutting of
the Nottingham and Lincoln Railway, and Goose Wong
Road, leading to Mapperly Plains.
The marl abounds with loose and thin layers of skerry,
or impure limestone, and in many places contains veins
D 3

58

EUDIMENTS OF T H E

of gypsum, or, as it is called, plaster stone, which are
extensively worked near Newark, and other places, for
the manufacture of plaster of Paris.
The water from the wells dug in these strata is
strongly impregnated with lime.
7. The colour of the bricks made at Nottingham and
in the neighbourhood is very various. For making red
bricks the clay is selected with care, and particular beds
only are used. For common bricks the earth is taken
as it comes, and the colour is very irregular and unsatisfactory, varying from a dull red to a dirty straw colour.
Some of the marl burns of a creamy white tint, and
has been lately used with much success in making
ornamental copings and other white ware.
8. I n the manufacture of common bricks no care is
taken in the selection of the clay, and it is worked up
as it comes to hand indiscriminately, the great object
of the manufacturer being to clear his yard; the same
price being paid for all clay used, whatever its quality.
Stones and pebbles are picked out by hand, but the
pieces of limestone are generally left to be crushed by
the rollers, and much bad material is worked up in this
way which could not be made use of if the tempering
were effected by treading and spade labour only.
There are, however, many beds which are sufficiently
free from limestone not to require grinding, and when
these are worked the rollers are not used.
9. For front bricks, and the superior qualities, the
clay is selected with more or less care, receives more
preparation previous to grinding, is ground finer, and
is sometimes left to mellow in cellars for a considerable
time before using.
10. For making rubbers for gauged arches, the clay
is carefully picked, and run through a wash-mill into

ART OF MAKING BRICKS AND T I L E S ,

59

pits, where it remains until by evaporation and settlement it has attained a proper degree of consistency.
The clay for this purpose is generally mixed with a certain quantity of sand to diminish the labour of rubbing
the bricks to gauge, the proportion varying according
to the quality of the clay. The sand used for this
purpose is the common rock sand, which burns of a
red colour,
11. The clay immediately near the town of Nottingham is not well suited for making roofing tiles, the
ware produced from it being generally very porous.
This statement, however, is not to be taken without
exceptions, as there is plenty of suitable clay for the
purpose within a few miles' distance.
12. The old houses in Nottingham are built with very
thin bricks, much of the old brickwork gauging 1 0 | in.
to 4 courses in height, including mortar joints. These
bricks are of a dark red colour, and were from works
that have been long since abandoned. The bricks now
made are much thicker, the walls of many new buildings gauging 21 in. to 7 courses in height, or about
13^ in. to 4 courses in height, including mortar joints.
The common bricks are of a very uneven colour, which
arises partly from the manner in which they are set in
the kiln, and partly from the want of care in selecting
the clay, and the quantity of limestone ground up with
it. From this circumstance the fronts of many of the
new buildings have a mottled appearance, which is
extremely unsightly.
.

GENERAL ARRANGEMENT OF A BRICKWORK.

13. The brick-yards from which the town of Nottingham is at present supplied are situated on the
slopes of a small valley along which runs the public

60

RUDIMENTS OF THE

road from Nottingham to Southwell, and, being situated on the sides of the hills, great facilities exist for
draining the workings and for bringing the ground into
cultivation again after the clay has been exhausted.
14. The proprietor of a brickwork usually rents the
required land from the owner of the soil, at a price per
acre, and in addition to the rent pays for all clay dug,
whatever its quality, at a set price per thousand bricks
made and sold, exclusive of those used for the erection
and repairs of the buildings and works.

ART OF MAKING B&IGKS AND TILES.

61

15. The arrangement of the several buildings varies
with each yard more or less; but the principle on
which they are laid out is the same in all cases, viz., to
advance towards the kiln at each process, so as to avoid
all unnecessary labour. This will be understood by
inspection of fig. 1, which, it must be understood, is not
an exact representation of a particular brickwork, but a
diagram to explain the principle of arrangement usually
followed. The pits from which the clay is dug are at
the rear of the works, and at some little distance from
them is placed the clay-mill, which, to save labour in
wheeling the clay, is shifted from time to time as the
workings recede from the kiln by the exhaustion of the
clay. This is, however, not always done, as, where the
mill has been fixed in a substantial manner, the saving
in labour would not repay the cost of re-erection.
The hovel or drying shed generally forms two sides
of a rectangular yard adjoining the public road, the
kiln being placed as close to the hovel as practicable,
and the working floors or flats in the rear of the latter.
By this concentration of plan, the distance to which
the bricks have to be carried between the successive
processes of moulding, drying, hacking and burning is
reduced to a minimum, which is an important point to
be attended to, as th£ raw bricks are shifted by hand
and not harrowed.
As it is" not always possible to obtain a supply of
water at those parts of the works where it is wanted
to be used, a water-cart* is kept at some yards for this
purpose, the supply being taken from a pond into which
the drainage of the works is conducted.
* The water-cart is seldom used, except where the water has to be
fetched a considerable distance—indeed rarely, but in times of drought.
It is usually carried, in the yard, in buckets with yokes, as in the time of
Pharaoh.

62

RUDIMENTS OF T H E

The goods for sale are stacked in the open part of
the yard as near the public road as practicable.
16. Clay-Mill.-^-The machinery used in grinding the
clay is very simple. The clay-mill consists of one or
more pairs of cast-iron rollers, set very close together
in a horizontal position, and driven by a horse who
walks in a circular track, and, by means of the beam to
which he is attached, puts in motion a horizontal bevelled
driving-wheel placed at the centre of the horse track.
A horizontal shaft connected at one end with one of
the rollers by a universal joint, and having a bevelled
pinion at the other end, communicates the motion of
the driving-wheel to the rollers by spur-wheels keyed
on their axles. The clay is tipped in a wooden hopper
placed over the rollers, and passing slowly between the
latter falls on a floor about 8 feet below them, where
it is tempered for the moulder.
17. The common clay-mill has only one set of rollers,
but the addition of a second set is a great improvement.
In this case the bottom rollers are placed almost in
contact with each other, and should be faced in the
lathe to make them perfectly true. If only one set be
used this is a useless expense, as the gauge to which
they are worked is too wide for any advantage to be
derived from it.
18. Figures 2, 3, 4 represent a one-horse mill with
a single pair of rollers 18 in. in diameter, and 30 in.
long, manufactured by Messrs. Clayton and Shuttleworth, of Lincoln, who kindly furnished the drawings
from which the engravings have been made. The
detailed description of the several parts will be found
in art. 69.

ART OF MAKING BRICKS AND TILES.
Fig-.2

63

64

RUDIMENTS OF THE

ART OF MAKING BRICKS AND TILES.

65

JFK7.4.

This is a very good mill, of simple construction, and
not expensive, the cost when ready for fixing (exclusive
of foundations and brickwork) being £35.
I t cannot be too strongly insisted upon that the
machinery should be boxed up close, so as to prevent
stones or clay from clogging the wheels, as where this

66

RUDIMENTS OF THE

is not done the machinery will unavoidably become
deranged in a very short time.
19. In many yards, the horse-track is raised to the
level of the top of the hopper, so that none of the
machinery is exposed. A very good arrangement of
this kind is shown in fig. 5, of which a detailed description is given in art. 69.
20. The quantity of work performed will of course
vary greatly, according to the distance between the
rollers and the consequent fineness to which the clay is
ground. One mill will grind sufficient clay to keep six
moulders fully employed, and therefore there are very
few yards in which the rollers are constantly in work.
21. The length of time during which a clay-mill will
last in good working condition is chiefly regulated by
the wear of the rollers. If the iron is of very uniform
quality, and care be taken to pick out all the pebbles
from the clay, a pair of rollers will last many years.
The other parts of the machinery will last with care for
an indefinite length of time.
22. Wash-mill.—The wash-mill is used only in the
manufacture of arch bricks, and does not differ from
that used in other places. The only one visited by the
author consists of a circular trough, lined with brickwork, in which the clay is cut and stirred up with
upright knives fastened to a horse-beam. From this
trough, the slip runs through a grating into a brick
tank, where it remains until by evaporation and settlement it becomes sufficiently consolidated for use.
23. The Pug-mill is not used in the Nottingham*
brick-yards; the tempering of the clay, after grinding,
being effected by treading and spade labour. Instead
of the clay being tempered directly after grinding, it is
* It is, however, used in the neighbourhood.

ART OF MAKING BRICKS AND T I L E S .

r

68

RUDIMENTS OF THE

sometimes deposited to ripen in damp cellars for a year
or more. This is done for the best bricks only.
24. The Moulding Sand used is the common rock
sand, which burns of a red colour. I n making white
bricks this is a great disadvantage, as it causes red
streaks, which greatly injure their colour. The sand is
only used to sprinkle upon the table to prevent the clay
from adhering thereto, and therefore sand with a sharp
grit is preferred.
25. The Moulding Table is shown in fig. 6. I t is
Fig. 6.

ART OF MAKING BRICKS AND TILES.

69

furnished with a sand-box, which is sometimes fixed,to
the table, as shown in the cut, and sometimes detached,
and with a water-box, in which the moulder dips his
hands every time he moulds a brick. In the operation
of moulding, the moulder stands in front of the table,
with the water-box immediately in front of him, the
tempered clay at his right hand, and the sand-box at
his left. A sloping plank is placed at one end of the
table to enable the boy who brings the clay from the
temperer to deposit it more conveniently on the table.
The boy who takes off the newly-made bricks, and
brings back the empty mould, stands on the side of the
table opposite the moulder, to the right of the waterbox, in which he washes his hands after each journey,
to prevent the clay from drying on them.
The cost of a moulding table varies according to the
care with which it is made. Such a one as shown in
the cut will cost about 20s., and will last, with occasional
repairs, for several years. The part where the brick is
moulded soon becomes worn, and has to be cased as
shown in the cut. This casing extends over the part
where the brick is taken off by the carrier boy; but, as
the wear is not uniform over this space, the easing is in
two or more pieces, the part where the brick is moulded
wearing much faster than the others, and requiring
renewal sooner.
It is of importance that the drippings from the table
should not fall on the drying floor, as they would render
it slippery and unfit for use; a rim is therefore placed
at one end, and along a part of one side of the table,
and the opposite side is furnished with a kind of apron
and gutter, by means of which the slush is conducted to
a tub placed under one corner of the table, but which ia
not shown in the cut.

70

RUDIMENTS OF THE

26. Brick Moulds.—Until lately the moulds used
were made of wood, but these have been almost entirely
superseded by brass, or, as they are technically called,
copper, moulds.
JF^.7.
There are several
different ways in
which these moulds
are made.
Sometimes the brass work
is merely an inside
lining, screwed to a
wooden mould; but
the best construction
appears to be that
shown in fig. 7, in which the mould is of brass, cast in
four pieces, and riveted together at the angles, the woodwork being in four distinct pieces and attached to the
brass mould by the angle rivets. These moulds are
costly, and formerly a pair of moulds cost <£2, but they
may now be had for £ 1 5s. the pair.
It will be seen, by reference to the engraving, that the
brass overlaps the woodwork all round the mould on
each side, and these portions of the mould wear away
very rapidly, so that the bricks made at the close of the
season are considerably thinner than those made at its
commencement. This renders it necessary to renew the
projecting rims from time to time as they become worn
down with use, and this will require to be done every
season if the mould has been in constant use. I t is an
expensive operation, as the new rim has to be brazed on
to the old part, and this must be done with great nicety,
and so as to make a perfectly flush joint on the inside
of the mould, or the latter would be rendered useless.
The cost of plating a pair of moulds is nearly the same

ART OF MAKING BRICKS AND TILES.

71

as their original cost, 20s. being charged for the operation, and therefore it would be preferable to use the
moulds until they are quite worn out, and then to replace
them with new ones.
27. The use of copper moulds is confined to the
making of building bricks, and quarries for paving
floors, their weight and great cost preventing their
employment for larger articles.
28. The mould has no bottom as in the London
practice, nor is it placed upon a raised moulding board
as in Staffordshire; but rests on the moulding table
itself, the top and bottom beds of the brick being formed
at two distinct operations with a little instrument called
a plane.
/
29. The Plane, fig. 8, is usually
made 9 in. long by 3 in. broad,
with a handle at one end. Its use
is to compress the clay in the
mould, and to work over the top
and bottom beds of the brick to
give them an even surface.
The strike is not used at Nottingham.
30. The Flats, or working floors, are prepared with
care, by levelling and rolling, so as to make them hard
and even, and are laid out with a slight fall, so that no
water may lodge on them. They are well sanded, and
constant care is requisite to keep them free from weeds.
Their usual width is about 10 yards. In unfavourable
weather a single moulder will sometimes have as many
as 7,000 bricks on the flats at once, for which an area
of from 300 to 400 superficial yards will be required.
This, however, is an extreme case, and in good drying
weather a moulder does not require more than half that
extent of floor, or even less than this.

72

R U D I M E N T 3 OF T H E

31. The Hovel, or drying shed, in which the bricksi
are hacked, is generally built in the roughest and
cheapest manner possible, with open sides and a tiled
roof, supported by wooden posts or brick piers; the
width of the hovel is about 18 ft., or rather more than
the length of a hack, but the eaves are made to project
a couple of feet or so beyond this distance, in order to
give additional shelter from the rain, for which reason,
as well as for the sake of economy, the eaves are carried
down so low as to make it necessary to stoop to enter
the shed.
Some of the hovels have flues under the floor, the
fire-places being placed in a pit sunk at one end of the
hovel, and the chimney at the opposite end. These
flues are made use of when the demand for bricks is
so great that sufficient time cannot be allowed for drying in the open air, and also during inclement seasons.
The sides of the hovel are then walled up with loose
brickwork to retain the heat. No specific rule can be
given for the relative sizes of the hovel and the drying
floor. The common pra #ice appears to be to make
them of the same length, which allows ample room,
and enables the moulder to keep a portion of his shed
always available as a drying floor when the weather is
too wet to allow of the bricks being laid out on the
flats. "When this is the case the moulder protects the
raw bricks from drafts, by surrounding them with a
skirting, so to speak, of planks. This is a very necessary precaution, for the currents of air from different
parts of the shed would cause the bricks to dry unequally, and they would crack and become unsound.
Matting is frequently hung up at the sides of the hovel
for this purpose, and is also much used in some yards
to prevent the finer clays, when tempered, from drying

ART OF MAKING BRICKS AND T I L E S .

73

too rapidly where cellars are not provided for that
purpose.
32. The above description applies to the ordinary
hovel, but the best front bricks are dried wholly under
cover in a brick hovel inclosed by walls on all sides,
and furnished with flues, by which the place is kept
at a regular temperature. The expense, however, of
conducting the whole of the drying under cover in
this manner is too great to allow of its general adoption.
33. The clapper, fig. 9,
Fig. 9.
is simply a piece of board
12 in. by J3 in. with a
handle on one side. It
is used to flatten the surfapes of the bricks as
they lie on the floors,
and the bricks are also
beaten with it during the process of hacking, to correct
any warping which may have taken pl&ce in the first
stage of drying.
F
34. Dressing Bench.—
W-10Fig. 10. This is simply a
stout bench, tQ which is
fitted a plate of cast-iron,
on which the best front
bricks are rubbed or polished, to make them perfectly true and even; the
workman, at the same time,
beating them with a wedge-shaped beater, tipped with
iron, called a dresser, fig. ] 1 , This operation toughens
the brick, corrects any warping which may have taken
place, and leaves the arrises very sharp.

74

RUDIMENTS 0? TBEE

35. Machinery for
pressing Bricks, — In,
some
yards
screw
presses are used for
pressing front bricks,
and with considerable
success. It is, however>
questionable whether
they are as durable as
those dressed by hana. In making machinery for this
purpose the great desiderata are, 1st, to make the metal
mould in which the brick is compressed so strong that
it shall not spring on the application of the power; and,
2nd, that the piston shall exactly fit the mould: when,
from bad workmanship or long use, this is not the case,
the clay is forced between the piston and the mould for
a short distance, leaving a slightly-raised edge all round
the side of the brick.
36. We do not propose here ta enter upon a comparison of the respective merits of machine-pressed
bricks and those dressed by hand. The operation of
dressing on the bench requires an experienced workman, whilst a common labourer can use a machine.
For this reason machine-pressed bricks can be produced much cheaper than those dressed by hand,
and there is little inducement to employ the latter
process.
37. Kiln.—The kilns vary considerably as regards
their dimensions and constructive details, but they are
all built on the same principle.
The kiln shown in figs. 12, 13, 14, 15, 16, and 17, is
a good one, though rather weak at the angles, and
will convey an idea of the general construction. (See
chap. ix.? page 210.)

ART OF MAKING BRICKS AND TITLES.

75

Fig. 12;

*

J

9

,

I

.

J

It consists of four upright walls, inclosing a rectangular chamber. The floor is sunk about 4 ft. below the
general surface of the ground, and is not paved. The
doorways for setting and drawing the kiln are merely
narrow openings at the ends of the kiln, raised a step
above the ground, and about 5 ft. from the floor. The
fire-rholes are arched openings opposite each other on
the sides of the kiln, lined with fire bricks, which require
to be renewed from time to time, generally every season.
The width of these holes is reduced to the required space
E2

76

RUDIMENTS OF THE

by temporary piers of brickwork, sq as to leave a
narrow opening about 8 in. wide and about 8 ft. high.
This will be understood by reference to fig. 12, in whiph
Fig. 13,

Fig. 14.

ART OF MAKING BRICKS AND TILES.

Fig. 15.

Fig. 1&

Fig. 17.

the dark shading shows the fire-brick lining, and the
unshaded parts the temporary piers.
On each side of the kiln a pit is sunk to the level of
the floor, and covered with a lean-to roof, which protects
the fuel and the fire-man from the weather, and prevents
the wind from setting against the fires. The walls of
the kiln are about 3 ft. thick, and are built of old bricks,
rubble stone, and the refuse of the yard. No mortar is
used, as the use of lime would destroy the brickwork,

78

RUDIMENTS OF THE

under the intense heat to which the walls are exposed.
The bricks are therefore set in loam or fire-clay, if it
can be readily procured. The fire-bricks for lining the
fire-holes are sometimes brought from Ilkeston, where
excellent fire-clay is worked, but it is most common to
make them at the yards with such clay as can be got
in the neighbourhood, which answers pretty well. This
clay is brought from the ^neighbouring collieries, and
is obtained when sinking shafts; there is no fire-clay
at any of the Nottingham yards.
38. Instead of being built with walls of parallel
thickness, resting on arches, as in the example just
described, some kilns are built with walls of great
thickness at bottom, and diminishing by set-offs until,
near the top of the kiln, they are comparatively thin.
Many kilns also are provided with massive buttresses
at the angles, with the intention of counteractingthe tendency which the walls have to lift themselves
with the heat.
Very great care is requisite in drying a newly-built
kiln, or the walls will be cracked at the first firing, and
the thicker the walls the greater the care necessary.
39. So long as the brickwork is sufficiently thick to
retain the heat, no purpose is attained by increasing
the strength of the walls, unless they are made so
massive that they are unaffected by the heat externally,
and heavy enough to counteract the lifting cause by the
expansion of the sides exposed to the fire. In the one
case the walls expand bodily with the heat, forming
large and dangerous cracks; in the other, separation
takes place between the inside and outside of the walls,
from the expansion of the parts most exposed to the
heat, and the kiln soon requires relining.
40. The kiln shown in figs. 13 to 17 is an example

ART OF MAKING BRICKS AND T I L E S .

79

Fig*. 1&

of tjie mode of building with walls of the same thickness top and bottom; that shown in fig. 18 is one of a
more massive construction, and has buttresses at the
angles. The upper part of this kiln is formed by building, in a temporary manner, a thin parapet round the
inside of the top of the walls, about a couple of feet in
height. This expedient is often resorted to for the sake
of increasing the capacity of a kiln at a small expense.
41. Some of the kilns are provided with a flight of
steps by which access is obtained to the top, in others
ladders are used for t*his purpose. Many of the kilns
have also a kind of light fence round the top, made of
rough poles. This serves as a protection from falling,
and as a scaffold to which screens may be hung in
windy weather to keep the wind from setting on the
top of the kiln. This fence is shown in fig. 2. The
outside staircase is shown in figs. 1, 13, and 1642. The sizes of the kilns vary considerably. A
kiln such as that shown in figs. 12 to 17, 20 ft. long,
10 wide, and 12 ft. high, will, with the addition of a
parapet, burn 25,000 bricks at once, and will require
rather more than that number of bricks for its erection.
The cost of such a kiln would be from £30 to <£50, the
value of the materials being almost nominal.
The capacity of a kiln may be roughly calculated on
the assumption that ten bricks require a cubic foot of
space in the kiln, but much, of course, will depend on

$0

RUDIMENTS OF THE

the nature of the clay and the amount of shrinkage
before burning.
43. A well-built kiln will last for inany years with
occasional repairs.
PROCESS OF BRICKMAKING.

44. Clay digging.—The clay or marl is, or should be,
dug in the autumn, and collected in large heaps at the
bottom of the slopes, to be mellowed by the winter frosts.
These heaps are shown in fig. 1.
The cost of this operation varies from Is. to Is. 9d.
per 1,000 bricks, according to the labour of getting the
clay, and the distance to which it has to be wheeled.
45. Tempering.—In the spring the clay is turned over
fey sjp&d'e labour, being at the same time well watered
and trodden. The pebbles and large lumps of limestone are picked out by hand with more or less care.
The prepared clay is then wheeled to the mill, and
tipped into the, hopper. Sometimes the clay, after
being ground, is at once tempered for use on the floor
beneath the rollers ; but for the best bricks* a§ b'&foite
stated, it is allowed to rBmain in cellars to ripen for a
year or more.
46. The temperer is generally paid by the moulder,
who contracts for tempering, moulding, and hacking at
a price per 1,000. The cost of tempering for common
bricks is about Is. 3d., exclusive Of the cost of horsing
the mill, which is borne by the proprietor of the yards
One temperer will keep one moulding-table constantly
supplied, and will also assist the moulder in getting up
his bricks from the floor.
47. Moulding.—A sufficient quantity of clay having
been prepared on the tempering floor, one of the
moulder's boys takes up as large a lump as he can

ART OF MAKING BRICKS AND TILES.

81

conveniently carry, and, placing it on his head, walks
with it to the moulding table, and walking up the
sloping plank, deposits it at the end of the table, to the
right hand of the moulder at B, fig. 6.
The moulder having sprinkled some dry sand over
the part of the table marked D, takes from the heap of
tempered clay a piece sufficient to make a brick, and
kneads this clot with his hands on the sanded part of
the table, so as to bring it approximately into shape.
He then raises the clot in the air, and dashes it with
some force into the mould, striking off the superfluous
clay with his fingers. He then dips his hands into the
water-box, and, with very wet hands, works over the
face of the brick, so as to force the clay perfectly into
the mould in every part. He next takes the plane and
passes it backwards and forwards with considerable
pressure, until the face of the brick is flush with the
edges of the mould, and then, reversing the mould,
planes the underside in the same way. The brick being
moulded, the moulder slides it on the wet table to his
left hand side, where it is taken off by a second boy,
who carries it, mould and all, to an unoccupied part of
the floor, where he turns it out carefully on one of its
sides, and returns with the empty mould. Meanwhile
the moulder has made another brick in a second mould,
which is now ready to be taken off, and this process is
repeated until the distance to an unoccupied part of
the floor is too great to allow of the boys returning in
time, and the table is then shifted to another part of
the floor.
48. Drying,—After the bricks have remained for a
few hours in the position in which they were first placed
on the floors, they are turned on their edges by a boy>
who turns up two at once, one with each hand. They
E3

m

HTJDIMENTS OF THfc

remain in this position a few hours longer, and are then
laid flat on the opposite side to that on which they were
first placed. Careful nioulders sprinkle sand over the
wet bricks as they lie on the floor, which absorbs the
superabundant moisture, and renders them less liable
to crack; but this is not always done.
The new bricks sometimes also undergo a slight
dressing with the clapper, to take off any roughness at
the edges, and to correct any alteration of form which
may have taken place on turning them out of the mould,
and in some cases they are scraped with a small iron
scraper, to remove any dirt that may adhere to them.
After lying flat a few hours longer, they are carried
by the boys, three at a time, to the hovel, where the
moulder builds them into hacks 50 bricks long and 14
courses high, each hack containing 700 bricks. As the
bricks are hacked they are batted with the clapper, to
correct any warping which may have taken place whilst
lying on the floors. The bricks remain in the hovel
without being again shifted, until they are ready for
burning.
49. The time allowed for drying varies with the
weather, the size of the kiln^ and the demand for bricks.
Some brickmakers get the bricks out of the kiln within
a fortnight of their leaving the moulds, but this haste
is very prejudicial to the soundness of the bricks, and,
as a general rule> three weeks is the least time that
should be allowed for drying.
The time that the raw bricks lie on the flats depends
solely on the weather. In good drying weather the
bricks are made one day and hacked the next; but at
other times several days may elapse before they are fit
for hacking.
50. It is not very easy to separate the cost of hacking

ART OF MAKING BRICKS AND TILES.

83

from that of moulding, as both operations are performed by the moulder. The price for moulding, including tempering and hacking, is from 5s. per 1,000,
and upwards; 5s. 3d. is a common price. Where the
clay is ground the moulder pays for feeding the mill,
but not for horsing it, this expense being borne by the
proprietor of the yard.
51. The above description refers to the ordinary
mode of proceeding, but for facing-bricks additional
processes are employed. Pressed bricks, as their name
implies, are prepared by putting the raw bricks one at
a time, when nearly dry, into a metal mould, in which
they are forcibly compressed by the action of a powerful
lever which forces up the piston forming the bottom of
the mould. This gives a very beautiful face to the
brick, and leaves the arrises very sharp, but bricks so
prepared require longer time for drying and judicious
management in the kiln, otherwise they will be unsound, and when exposed to the weather soon become
perished.
5&. Polished bricks, as they are called, are rubbed
upon a bench plated with iron, to make their surfaces
perfectly even, and are also dressed with a dresser, as
before described. This process is only gone through
with the very best bricks, and its cost is such that it is
not employed to any very great extent.
53. The contraction of the clay in drying is very
slight, and no perceptible diminution of size takes
place in burning if the bricks have been previously
choroughly dried.
The brick moulds are made of different sizes at different yards, their proportions having been altered from
time to time, so as to increase the depths of the moulds
at the expense of the other dimensions.

84

RUDIMENTS OF THE

When the thickness of a piece of brickwork is m&U
sured by the number of bricks, as in house building,
and not by feet and inches, as in building the piers of
bridges and other solid works, the number of bricks
required for the execution of a rod of brickwork is
considerably reduced by a very trifling addition to the
thickness of the bricks, and this is always an inducement to purchasers to prefer the yards where the
deepest moulds are used.
The largest common bricks now made measure, when
burnt, 9 | in. long, 4f in. wide, and 3 ^ in. thick, or
thereabouts; the size of the moulds being 9§ in. long
by 4^|. in. wide, and 3 f in. deep. These bricks weigh
about 7 lbs. 15 oz. when burnt.
The best red facing-bricks made at Mr. Wood's yard,
in the Carlton Road, measure, when burnt, 9 J in. long^
4 | in. wide, and 2^f in. thick. The moulds for these
bricks are 10 in. long, 4f in. wide, and 3J in. deep.
54. A good moulder, if solely occupied in moulding,
will turn out 2,000 bricks in a day, between 6 A.M. and
6 P.M. ; but as nearly one-third of the moulder's time is
taken up with hacking, the average day's work is not
more than about 1,300 per day, or between 7,000 and *
8,000 weekly.
55. Burning.—The setting of the kiln is an operas
tion on which mucli depends, and requires to be done
by an experienced hand, as there is a great deal of art
in arranging the bricks in a proper manner, so as to
allow the heat to be diffused equally through the kiln,
and to afford a proper draught, so as to obtain the
greatest amount of steady heat with the smallest expenditure of fuel.
The lower part of the kiln is filled with common
bricks, narrow, openings being left, as shown by the

ART OF MAKING BRICKS AND TILES.

85

dotted lines in fig. 12, forming flues connecting the
opposite fire-holes, the tops of these flues being formed
by oversetting the bricks on each side till they meet.
These flues are of the same height as the fire-holes.
The best bricks* are placed in the middle of the kiln,
and above these again are placed common bricks up to
the top. The bricks are not placed close together, but
a space is left all round each brick to allow of the passage of the heat round i t ; the bricks in the successive
courses being crossed either slantwise, or at right angles
to each other. When a brick rests partly on others,
and is partly exposed to the fire, the 'exposed part will
commonly be found of a lighter red than those to which
the fire has had no access, and this is one great cause"
of the mottled colour of the Nottingham bricks. When,^
therefore, it is wished to produce bricks of a uniform
red tint, great care is taken to keep the faces and ends
of the bricks in close contact, crossing them every few
courses only.
The kiln being topped, the doorways are built up with
^refuse brick and plastered over with clay, to prevent
the admission of currents of cold air, and the fires being
lighted, the heat is got up gradually, care being taken
hot to urge the fires, until all the steam is driven off
from the bricks, and the actual burning begins. When
the fire has attained its full heat, the fire-holes are
partially stopped with clay, and the top of the kiln is
covered over with earth, turfs, or boards, to check the
draught, and a steady uniform heat is kept up until
the completion of the burning, which generally occupies
three days and three nights from the first lighting of
* If tiles be burnt at the same time, which is frequently the case, as
they cannot be burnt alone without great waste, they take the same
position in the kiln tis dressed bricks.

86

RUDIMENTS OF THE

the fires ; at the expiration of which time the fire-holes
are completely stopped, and the fires put out; after the
fires have been extinguished, the kiln should be allowed
to cool very gradually, as the soundness of the bricks is
much deteriorated by the kiln being opened too soon;
this, however, is a point not sufficiently attended to.
56. The fuel employed is coal,* the quantity f used
being about half a ton per 1,000 bricks, the exact
amount depending on the quality of the fuel and the
judicious setting of the kiln. The town of Nottingham
being situated on the very edge of the Nottinghamshire
coal-field, the cost of firing is very low, and excellent
coal can be laid down at the yards at from 8s. 6d. per
ton upwards. The small coal or slack frequently used
in the early stage of burning does not cost more than
5s. to 6s. per ton.
57. The colour and soundness of the bricks vary
according to their position in the kiln and the intensity
of the heat to which they have been exposed. Those
nearest the fire become partially vitrified, and of a
blackish tint. Those which have been more favourably
placed burn of various tints according to the nature of
the clay, from red to straw colour and white, and when
struck together ring with a clear metallic sound. Those
which are underburnt are tender, of a pale red colour^,
and give a dull sound when struck together.
58. The cost of setting and drawing the kiln is generally reckoned at Is. 6d. per 1,000, this including
stacking the bricks in the yard, or placing them in
the carts of the purchasers. If, however they are
* Soft coal is preferred.
f In some great yards a deal of coal is wasted on the top of the kiln.
As the heat has always an upward tendency, this has very little effect on
the bricks, and a great deal of fuel is wasted in smoke and flame.

ART OF MAKING BRICKS AND T I L E S .

87

not for immediate sale, an additional 6d. is charged for
loading the carts.
59. The labour in firing is reckoned at Is. per
1,000.
60. At Nottingham, and at the yards in the neighbourhood, many varieties of brick are manufactured;
as cant, or splayed bricks, for plinths; weathered and
throated copings of several sizes; round copings;
bricks with quarter-round ends; wedge-shaped bricks
for culverts ; compass, or curved bricks for lining shafts
and wells, and also paving, roofing, and draining tiles
of all descriptions. It is unnecessary to enter into any
details on the manufacture of these articles, as they
offer no particular points of interest. It may, however,
be worth while to mention that the use of copper
moulds is confined to the manufacture of those articles
which are of a convenient size, and for which there is
a large demand; the moulds for cant bricks, compass
bricks, and other fancy articles for which there is only
'a limited demand, being made of wood.
COST OF MANUFACTURE*

61. Land, and Brick-earth.—The proprietor of a
brickwork usually rents the necessary land at a price
per acre, and in addition pays for all clay removed at a
set price, whatever its quality.
As the brick-earth is exhausted, or the workings
reach an inconvenient depth, the ground is levelled and
again thrown into cultivation. This is of course done
at the earliest period possible • and in some cases the
rental of the land is nearly made up by the profit derived from cultivating the site of the exhausted workings, so that it is impossible to give an accurate estimate

88

RUDIMENTS OF THE

of the proportion which the rental of the land bears to
the total cost of manufacture, as it must vary widely in
each particular case. This remark does not hold good
with regard to the brick-earth, which is paid for at the
rate of Sd. per cubic yard, or 25. per 1,000 bricks, a
thousand bricks requiring about 3 cubic yards of clay.
It must be remembered that, as above stated, this
price is paid for all clay removed, whether suitable or
not for briekmaking. For common bricks the earth is
taken as it comes, good and bad being ground up together ; the cost of grinding being less than the loss
which would result from the rejection of the inferior
earths, which are often so hard, and contain so much
skerry in pieces of all sizes from that of a walnut to that
of a man^s head, that they could not be worked up by
the ordinary process of tempering by treading and spade
labour only. For front bricks and the best qualities^
the clay is Carefully picked, and the cost is propor-*
tionately increased thereby.
No estimate can be given for the amount of land
required for making a given number of bricks, as it
depends on the situation of the yard and the depth to
which the workings can be carried.
62. Buildings and Machinery.—From the circumstance that in existing yards the buildings have been
erected at different times without any very systematic
plan> it is not very easy to ascertain what are the best
relative sizes of working floors, hovels and kilns, or
what extent of building and plant are required for
working a yard to the greatest advantage. Unless the
manufacture be conducted on a very large scale, the
grinding-mill will, in most cases, be often unemployed;
and the wash-mill being used only in the manufacture
of arch bricks, it is only in the immediate neighbour*

ART OF MAKING BRICKS AND TILES.

89

hood of a large town that a return for the cost of its
erection can be hoped for. It will always be found an
advantage to have an excess of shed-room rather than
the contrary.
63. The following rough estimate will give an idea of
the buildings and machinery required for mounting
a new yard, to produce from 40,000 to 50,000 per
week:—
1 day-mill*
120 yards lineal of hovel, 6 yards wide.
1,200 yards superficial of working floor.
This extent of hovel and floor will be sufficient for the
operations of six moulders; and, taking the work of
each moulder to average throughout the season 1,300
Jtefc diem, the week's work of the six moulders would
produce 46,800 per week, or in round numbers 140,000
every three weeks.
This rate of production would render necessary two
kilns, each to burn 35,000, and these kilns would be
kept in constant activity, each kiln being fired twice
6 very three weeks.
64. For a yard in which it is proposed to make all
kinds of brick ware additional buildings will be required,
as:—
Cellars for ripening the ground clay;
A tempering shed, for tempering under cover;
One or more drying-houses, provided with furnaces
and flues \
A wash-mill for running the clay for making rubbers.
Besides the above erections, there will be required in
all yards stabling to a greater or less extent; a cottage
for the under-taker of the yard; and sheds and outbuildings for keeping tools, carts, and implements.

90

RUDIMENTS OF T H E

65. Tools.—The
are:—
A
A
A
A

tools required by each moulder

pair of brass moulds;
moulding table, and appurtenances complete;
plane;
clapper.

In addition to these implements a variety of other
articles are required, as shovels, picks, barrows, planks,
sand baskets, sieves, &c, which are kept in store by
the proprietor of the yard, and supplied to the men as
required.
66. Labour.—The proprietor of the yard finds all
tools and implements, sand, and coals, and horses the
mills. The general management of the yard is conducted by an under-taker, who superintends the yard
and contracts with the proprietor for all the labour
required in the actual manufacture, at a price per
.1,000 on the tale of bricks delivered from the kiln,
the under-taker bearing all loss from frost, wet, or
other causes.
The under-taker sublets the moulding to a moulder,
who contracts with him at a price per 1,000 to mould
and hack the bricks* ready for setting in the kiln; the
moulder employing two boys to assist him in moulding
and hacking, and also a temperer, who tempers the
clay for him, and assists in getting up the bricks from
the floor. The first turning over of the clay is performed by labourers, under the direction of the undertaker, who, with the assistance of a few boys and
labourers, sets and draws the kilns himself, and. attends
to the burning,
67. The actual selling price of bricks is regulated
more by the demand and the amount of competition

ART OF MAKING BRICKS AND TILES.

91

than by the cost of their production. Good building
bricks, made in copper moulds, may be had in Nottingham at 25s. per 1,000; but a fair selling price may
be considered as 28s. pet 1,000> which may be thus
subdivided:—
Clay digging
.
.
.
.
.per
Turning over-and watering clay and feeding mill
Grinding
.
.
.
.
.
.
.
Tempering for moulder
Moulding, drying and hacking
. . .
Setting and drawing kiln '.
.
.
.
Burning

1,000
„
„
„
„
„
„

Total cost of labour .
.
, „
Coal, half a ton, at 8s
„
Duty, os. lOd. per 1,000, with 5 per cent, added
„
Clay .
„
Rent, tools, machinery, and profit . . .
„
Selling price at yard

.

.

.

„

£ s. d.
0 1 6
0 0 8
0 0 6
0 0 4
0 4 0
0 1 6
0 1 0
0
0
0
0
0

9
4
6
2
6

6
0
1^
0
4|

1 8 0

This may be considered as the lowest price which
will afford any profit to the proprietor of the yard,
when proper allowance is made for depreciation in
buildings and machinery, tools, repairs, and other
contingencies.
68. The relative value of the different qualities of
brick may be thus stated:—
Common bricks (the clay not picked) .
. per 1,000
Front bricks (made in copper moulds, the clay
picked)
.
.
.
.
,
.
.
„
Polished bricks (made in copper moulds, the
earth selected with care, and the bricks
dressed on -a bench)
•
•
•
„

£ s. d.
1 8 0
1 13 0
3 0 0

92

RUDIMENTS OF THE

69.

R E F E R E N C E TQ TkE

ILLUSTRATIONS ACCOMPANYING

THE FOREGOING ACCOUNT OF B R I C K M A K I N G AS PRACTISED I N N O T T I N G H A M .

Fig. 1. General view of a brickwork, showing the arrangement of the
works.
A. The face of the workings.
B B. Heaps of brick-earth, dug in the autumn, to be worked up the
following season, after being mellowed by the winter frosts.
C. The clay-mill.
D D. The working floors, generally made about 9 or 10 yards wide.
B. The hovel. This hovel isflued,—the door at the end of the hovel
next the road is the entrance to the furnace pit; the chimney into
which the flues are conducted is showfi at the dpposite end. In
some drying houses the flues Eire made to" return nearly to the
furnaces before they are led into the chimney, so that the latter is
close to the former.
r. The kiln. This form of kiln is a weak one, and is liable to be
split from top to bottom by the expansion of the walls, from the
intense heat to which they are exposed. The reader will observe
the steps and the wooden fence round the top of the walls, mentioned in article 41.
G. Goods for sale.
This illustration is not an exact representation of any particular brickwork, but has been made up from the details of several yards, to show the
principle on which they are laid out; which is, to save all unnecessary
carriage of either brick-earth or bricks, from the time of first turning
over the clay to the stacking of the finished bricks in the sale yard.
Figs. 2, 3, and 4. Clay-mill, with a single pair of rollers 18 in*
in diameter, and 32 in. long, as manufactured by Messrs. Clayton and
Shuttleworth, of Lincoln. The letters of reference are the same in each
figure.
a. Horse beam, 12 feet long, from centre of horse track to centre of
driving wheel.
b. Bevelled driving wheel.
c. Pinion.
d. Driving shaft, l£in. diameter.
e. Universal joint.
ff. Spur wheels.
g g'. Cast-iron rollers 18 in. diameter and 32 in. long. The roller
marked g' is longer than the other, having a flange round each
end by which the roller g is kept in its proper position. The
roller marked g' is connected by the universal joint e with she
driving shaft d.
h. Wooden hopper.
i i. Cast-iron standards to support the hopper*
k k. Axles of rollers*

A$T OF MAKING BRICKS AND TILES.

93

11. Bearings for tlie axles k k* These bearings are made to slide
oii the bottom plate m, in order that the gauge of the rollers may
' be adjusted at pleasure.
m. Bottom plate, on which the bearings rest.
n. Strengthening bar.
o o. Adjusting screws, by which the rollers, can be set to any gauge,
according to the degree of fineness to which the clay is required
to be ground.
p. End beam of framing.
q q. Sides of framing.
r# Balance weight to horse beam.
The rollers in this mill are not faced in the lathe, but they are cast
upright in loam moulds, which insures great accuracy in casting, and
renders turning unnecessary, where only qne set of rollers is employed.
The arrangement of the rollers, when two or more sets are employed, is
shown in qhap. iv., figs. 1, 2, and 3, which shows the construction of the
clay-mills used in Staffordshire.
The temporary floor on which the clay falls after passing between the
rollers is formed about 8 feet below them, and is inclosed on three
sides with brick walls which support the wooden framework of the
machinery. The clay is prevented from adhering to the surfaces of the
rollers by strong knives fixed on their under sides.
Fig. 5 is a diagram showing an improved arrangement of the ordinary
clay-mill, in which the horse track is raised to the level of the top of tt^e
hopper, the whole of the machinery under the hopper being completely
boxed up, so that no dirt or stones, can lodge on the wheels. The driving
wheel is placed in a circular pit lined with brickwork to keep up the
borse track to the required height.
3Tig. 6j. Isometricalview of a moulding table.
A. Sloping plank, placed at one end of the table to enable the
moulder's boy to deposit the clay on the table.
B. End of the table where the tempered clay is deposited.
c. Sand box. This is not always fixed to the table. In many
cases it is a detached box, on three legs, placed close to the
moulding table.
D. The part of the table on which the clot is moulded.
E. The place where the clot is put into the mould.
JF. The water-box, in which the moulder dips his hands each time
he moulds a brick.
G. A slip of wood on which the plane rests in order to raise it from
the table, that the moulder may take it up the more readily.
H. The part of the table at which the brick is taken off. This part
of the table is always very wet, and the sliish runs off into
i. Gutter, to carry off the drippings from the table into a tub placed
beneath it, but which is not shown in the drawing. If the water
were allowed to run down on the working floor, the latter would
soon become wet and slippery, and unfit for receiving the bricks.
Fig. 7. Copper brick mould.
This kind of mould is cast in four pieces and riveted together, the
sides projecting half an inch beyond the ends. Each casting has
a flange at top and bottom, forming a rim half an inch wide all
round the top and bottom oC Ctoe mould. These rims become

94

RUDIMENTS OV THE

gradually worn down by the friction of the plane and the action of
the moulding sand, and require reflating from time to time. The
expense of replating with brass has induced a trial of iron rims,
but they have not been found to answer. The outside of the mould
is cased with wood, secured to the brass by the rivets. To give a
hold to the latter, each pair is passed through a piece of sheet
copper, as shown in the cut.
The moulds for making quarries are somewhat different, two of the
sides only being cased with wood, whilst the others are stiffened
by strengthening ribs cast on the sides of tb,e mpuld.
Fig. 8. The plane.
Fig. 9. The clapper.
Fig. 10. Bench on which the best bricks are polished and dressed with
a dresser, as described in art. 34.
Fig. 11. The dresser.
Figs. 12, 13, 14, 15,16, and 17. Plans, sections and elevations of a
kiln.
Fig. 12. Plan at level offloorj showing the firing sheds and fire-holes.
The latter^ in this example, are arched over, and are built of considerable width, which is afterwards reduced by temporary piers of
brickwork. In many kilns, however, the fire-holes are made at
once of the requisite width, and finished at top by oversetting the
bricks on each side till they meet, instead of being arched over,.
The fire-brick lining to the fire-holes is indicated in the plan by a
tint darker than that of the rest of the walls. The temporary piers
of brickwork are shown in outline only. These are pulled down
whenever the fire-brick lining requires, to be renewed. The floor
of the kiln is not paved.
Fig. 13. Plan, showing the. roofs of the firing sheds ( B B ) , and the
steps (A) leading to the top of the kiln.
Fig. 14. Cross section of kiln, taken through the firing sheds, and
showing the construction of the fire-holes.
Fig. 15. Longitudinal section, taken through the doorways at the
ends of the kiln, and showing the appearance of the fire-holes in
the inside.
Fig. 16. End elevation of kiln, showing the doorway and the ends of
the firing sheds, as well as the steps leading to the top of the kiln.
Fig. 17. Side elevation, with the firing shed removed, in order to
show the fire-holes.
Fig, 18. Perspective view of a kiln. This kiln is built, very differently
from that shown in the previousfigures,the walls being very massive
at the bottom, and diminishing in thickness as they ascend. The
angles are strengthened by buttresses. The doorways do not reach,
to the top of the walls, and are arched over, so that the latter form
a continuous terrace all round the top of the kiln, on which a thin*
parapet is built up in a temporary manner, to increase its capacity

ART OF MAKING BRICKS AND TILES*

95

CHAPTER IV.
BRICKMAKING AS PRACTISED IN THE STAFFORDSHIRE POTTERIES. B Y R. PROSSER, C.E.

1. Bricks.—There are made in this neighbourhood
the following sorts of bricks for building, viz., red, blue,
and drab, and also a blue brick used as a paviour for
footways, which brick is called a dust brick, from the
circumstance of coal dust being used when it is moulded.
When fired it has a smooth and somewhat glossy surface, and being very durable is extensively used as a
paviour.
2. The drab brick is used to a limited extent for
building, but more generally as a fire-brick by potters
and ironmasters; it is, however, inferior to the Stourbridge brick, the latter being used where intense heat is
generated.
3. Tiles.—There is a variety of other articles made
in the brickyards of this locality, as, roofing tiles in
several varieties, tubular drain tiles from 3 in. to 16 in.
meter, and generally 18 in. long; also floor tiles or
quarries both red and blue, the latter resembling the
blue brick,
4. Clay.—The blue colour is obtained from the same
clay that fires red by additional heat being generated
when blue is required, at a cost of half a ton more coal,
and two hours more time allowed per oven. The clays
or marls are selected for the purposes to which they are
best adapted, and an extensive supply of the best quality
for red is procured at Cobshurst, about two miles south
of Longton (which marl is used to make the red orna-

96

RUDIMENTS OF THE

mental and encaustic tiles, now so much admired, and
which are extensively made by Messrs. Minton and Co.,
of Stoke-upon-Trent). Marls and clays suitable for
brickmaking are plentiful, and of several varieties, in this
neighbourhood, but the most extensive bed of red marl
runs in an almost unbroken line through this country
from south to north, and generally west of the great
coal-field, and is worked with the same results at
Stourbridge, Tipton, JJanford, Basford, Tunstall, and
other places. A reference to a map of the country
will show the peculiarity of this lpng feed of stratified
marls.
5. I n the pottery district there are about ten distinct
sorts or strata. The following names are given to the
seven sorts most used; and their position with relation
to the earth's surface is shown by the or#er of their
names here given.
Top red marl, dun coloured, top yellow (rotten red,
not used), rninglecl, bottom yellpw, brown, and bottom
grey.
Seven of these marls vary but slightly in their
chemical composition, and, when used, three sorts at
least are generally mixed together. (For an Analysis
of the above?named marls, see Table 1, art. 37.)
In this locality there is a very favourable combination
of circumstances for the manufacture of ornamental
bricks for architectural decorations; and were architects to give the subject their attention, and such
bricks free from duty, much might be done.
6. The following description of the process and cost
of brick and tile-making will apply, first, to the make
of bricks, &c, upon the property of the manufacturer;
and, secondly, to the make of tiles, &c, at a yard which
is rented.

ART OF MAKING BRICKS AND TILES.

FIRST EXAMPLE.

97

BRICKMAKING.

7. Buildings and Plant.—This yard, with the ground
spened for work, has an area of about 6 acres, and has
the following buildings and machinery upon it, viz. :—
A 5-horse power steam engine ;
A set of horizontal rollers ;
(Three pairs to the set, placed over
each other).

A pug-mill ;
Six drying-houses ;
And nine ovens,

The drying-houses measure 40 yards in length, by 8^
yards in width, and have two flues under the floor
through their entire length.
At times they fire these nine ovens in one week;
and if used exclusively for bricks, each oven could
be fired five times in a fortnight. Besides bricks, the
following goods are made at this yard:—pipe tiles from
3< in. to 16 in. diameter, roof and ridge tiles, quarries,
dust bricks, &c.
8. Rate of Production.—Provided the make were
confined to bricks, with these conveniences they would
make 100,000 weekly during the usual brick season,
which at the present selling price, £1 8s. per 1,000,
gives a weekly produce value £140, which quantity
would pay in duty £27 l i s . 3d., the duty being 6s. \\d.
per 1,000, with 10 per cent, off: this leaves for cost of
production and profit £\\% 8s. 9d.
9. Tempering.—The marls used at this yard answer
to the description previously given. Their average contraction when mixed is 1 in 10; that is, a 10-in. mould
gives a 9-in. brick when fired, although some of the
varieties used separately contract 1 in 6. The marls
are dug and wheeled two runs for 4<d. to Id. per cube
yard, the price depending upon the difficulty of digging.
The marl is then placed in a hopper over the topmost

98

RUDIMENTS OF THE

rollers, and passing successively through the three pairs,
is deposited on a floor about 8 ft. below the hopper.
'The marl is then wheeled away, and some three or more
sorts mixed together with a proper quantity of water,
by spade labour (for the quantity of water in the marl
when dug, see Analysis, Table 1, art. 37). The mixed
marls, if wanted for tiles or dust bricks, are now passed
through the pug-mill; but if required for ordinary
bricks, the ground marls are mixed with marls that
have been weathered but not ground. Lastly, the marl
is tempered by spade labour until the proper degree of
plasticity is obtained.
10. Moulding.—The bricks are moulded by what is
called the slop-moulding process at the rate of 3,000
per day.* The price paid for tempering and moulding
is 46'. 6d. per 1,000. The process is as follows: the
temperer wheels the prepared marl in a barrow up a
plank, and empties it upon the moulding table. The
moulder having sprinkled sand upon the moulding
board, and upon that part of the table where the clot
is moulded, takes as much clay as will fill the mould,
and by a quick roll and a tap gives the clot an approximate form to the mould; he then lifts up this lump of
clay about 12 in. high, and with force throws it into
the mould, pressing it down with both hands to fill all
the cavities, and strikes off the surplus with a wooden
striker, which he throws into a small water-box in front
of him after each time of using.f An attendant boy,
who has previously dipped a mould in a water-trough
by the side of the table, places it on the table ready for
the moulder, and carrying away the moulded brick
*In the neighbourhood of Nottingham, where the bricks are not stricken,
but planed, the rate of production is only 2,000 per day.—ED.
f See chap, iii., art. 47.

ART OF MAKING BRICKS AND T I L E S .

99

in the mould, carefully empties it on its flat side on
the floor; these operations are repeated until the floor
is filled, when the moulding-table is removed to a
second floor.
11. Drying.—The floors are of different sizes; a convenient size is 25 yards in length by 6 yards in breadth,
upon which they will lay 3,000 bricks. Here they are
allowed to dry until sufficiently hard to handle and place
in hacks, the length of time depending upon the weather.
In quick drying weather they will remain half a day as
deposited from the mould, and half a day turned upon
edge, and afterward they are placed up in hacks, where
they remain until placed in the oven.
12. An ordinary blue brick weighs, wet from the
mould, 12 lbs. 4 oz.; when fired it weighs 8 lbs. 1 oz.,
having lost by evaporation in drying and burning 4 lbs.
3 oz., or 34 per cent, of its original weight.
The specific gravity of an ordinary blue brick
in the wet state from the mould is .
.
. 2,171
In the dry state, ready for the kiln
.
. 2,075
A.nd when burned, the specific gravity is
. 1,861
The Table on the next page shows the amount of
evaporation during the process of drying.
The total loss of weight in drying and burning is as
follows:—
196 ounces, the weight of a brick wet from the mould.
46
„
„
lost by drying, or 23J per cent.
150
21

„
„

„
„

dry ready for the kiln.
lost in burning, or 14 per cent.

129

„

„

of an ordinary blue brick,

13. Burning.—The oven is of a circular form, with a
» 2

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RUDIMENTS OF THE

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spherical top, and will contain 8,000 bricks, which are
so placed as to allow a space between the sides of each
for the action of heat, and an equal diffusion thereof.
When the oven is full, the elammins or doorway is made
up, and the fires kindled and kept burning 36 hours for
red, and 38 hours for blue bricks, consuming 3J tons of
coals for the former, and 4 tons for the latter. The

AIIT OF MAKING BRICKS AND TILES.

101

expense of setting, firing, and drawing an oven of
8,000 bricks is as follows: labour 12s., and coals
£1 13s. 4d.
14 Cost of Manufacture.—The details of the cost of
manufacture are as follows:—
Clay getting
per
Tempering and moulding.
.
.
.
Setting oven, firing and drawing
.
Coals, 4 tons at 8s. 4d., divided amongst 8,000
Duty, 5s. 10</., with 5 per cent, added
.
Bent, machinery, clay, contingencies, and profit

1,000
, ,
.,
„
„
„

Present selling price for ordinary blue bricks „

£
0
0
0
0
0
0

s. d.
1 6
4 9
1 6
4 2
6 1£
9 11|

1 8

0

15. Rental.—Brick-yards with mines of marls are set
with the following appendages, viz. : 1 oven, moulding
or drying-house, and pug-mill, with a breadth of brick
floor and marl bank sufficient to work one oven for £30
per annum j if two ovens are worked in the take, they
are set at £25 each*

102

KUBIMENTS OF THE
DESCRIPTION OF ILLUSTKATIONS.

16. Figs. I, %3 3, Machine, with three pairs of Rollers,
for grinding Marl.
Fig. 1. Side elevation.
Fig. 2 Front elevation, with the gearing removed.
Fig. 3. Elevation of gearing, No* 1 being the driving wheel

ART OF MAKING BRICKS AND TILES.

103

17. Fig. 4. Isometrical View of a Moulding Table.

A. Sand basket.
B. Detached water-box.
c. Moulding board
D. Water-box.
E. Clay knife.
In the process of moulding the moulder takes in his hand, from the
basket, a portion of sand, and dusts upon that part of the table where he
rolls the clay into the form necessary to mould; also upon tne moulding
board. The water-box or trough, B, is used by the boy to wash the mould
in, and is lower than the table, so as to be convenient for that purpose.
The water-box, D, is level with the table, and is used to throw the strike
in after each time of using.

18. Fig. 5. Isometrical View of a Brick Mould.

N B. The mould is made of oak, the edges plated with iron.

104

RUDIMENTS OF THE

19. Figs. 6, 7, 8, and 9. The Oven or Cupola
Fig. 6. Plan taken at top of fire-holes at level A B, Fig. 9.

J

i&L±jLX_L_L

Fig. 7. Plan, looking down on top of oven.

ART OF MAKING BRICKS AND TILES.

105

Fig. 8. Elevation.

Fig. 9. Section, on line c D, Fig. 6.

SECOND EXAMPLE.—TILE MAKING.

20. At Basford there is an extensive hill of good marls
from which eight brick-yards are supplied (working fourteen ovens)y some of which have been in work for forty
years. The makers are subject to the rental stated in
art. 15. The leading article made at these yards is roofing
F 3

106

RUDIMENTS OF THE

tiles; besides which are also made some quarries, dustbricks, drain tiles, and just so many common bricks as are
necessary for the manufacture of tiles, it being necessary,
in order to set the oven properly, to burn 2,000 bricks
with every oven of roof tiles, as will be hereafter explained. The process of tile making here is as follows :—
21. Weathering and Tempering.—The marl is dug
and spread upon slopes of this hill (which has a southeast aspect) to weather; the length of time depends
upon the quality of the air: a hot dry summer's day will
do good service, and three or four such days would
enable the makers to collect a thin surface in a workable condition. Frosty weather, provided it be dry, is
preferred; wet, and alternations of wet and dry, retard
the process of what is termed weathering. During a
hot dry season marl can be dug, weathered, and made
in one month, and this is frequently done. At the yards
here referred to, the workers collect their marls, so
weathered, at the foot of these slopes, and mix them
with a quantity of water. That to be used for tiles is
placed in the pug-mill, and about 1 cube yard per hour
is ground by one horse; and that used for common
bricks is not ground, but simply mixed and tempered.
The pug-mill consists of a wooden tub slightly
tapered, the largest end being uppermost; it is circular
and about 6 ft. high and 3 ft. diameter at the top or
largest end, in which a cast-iron spindle revolves,
carrying a series of flat steel arms, arranged so as to
form by rotation a spiral or worm-like motion upon the
clay, which is thereby pressed from a larger to a less
diameter of the tub in which the clay is confined, and
ultimately comes oozing out of an aperture at the
bottom: this operation kneads the clay, and more completely mixes it, giving it great cohesive power. This

ART OF MAKING BRICKS AND TILES.

107

clay or prepared marl is now ready to make roof tiles,
dust bricks, quarries, &c., and is wheeled away to the
stock kept under cover for that purpose. The tiles, and
all articles in the making of which coal-dust is used,
are made in a building called by brickmakers the hovel
or drying house: but they prefer placing their tiles
when first moulded in the open air, weather permitting.
The moulding of roofing tiles varies from that of bricks
before described, principally in the clay being stiffer,
and coal dust being thrown in the mould each time it
is filled.
22. Moulding.—The mould is 12 in. by 7f in. and
\ in. thick, made of oak plated with iron. The moulder
at his bench takes up a lump of clay, and works it by
hand into an oblong square, somewhat less than the
mould, say 11 in. by 7 in. or thereabout; the mould is
placed upon the bench, and fine coal-dust thrown into
i t ; the man then takes up the lump of clay in the right
position for the mould, and throws it into it with considerable force ; then, with a brass wire strained upon a
wooden bow, cuts off the surplus clay level with the
mould, removes the lump, and finishes moulding the
clay left in the mould by adding a little clay if it be
wanted, and smooths it over with a wooden tool. By
his side upon the bench he has two thin boards about
the size of the moulded tile, their surfaces are dusted
over with coal-dust; upon one of these he places the
moulded tile, without the mould, the half circular projections extending beyond the board; and so he repeats
the process of moulding at the rate of from 1,300 to
1,500 per day, adding more clay to his lump about every
six tiles moulded, and in quantity about as much as the
six tiles moulded.
23. Drying.—The attendant boy carries away two

108

RUDIMENTS OF THE

tiles at each time to the floor; he takes up one on the
board, and by the thick part of the hand presses up the
two projections at right angles with the face of the tile,
and then places board and tile on his head, and takes
up a second and operates upon this in like manner, as
he walks to the floor, where he lays the two tiles,
carrying the boards back to the moulding bench; and
so he repeats his operations.
The tiles remain on this floor, out of doors in fine
weather, about four hours ; they are then collected and
placed close together, the nib end changed alternately
to allow of their resting close and square; in this state
they are walled up in a dry but not hot situation, and
so remain for a day or two: this is said to toughen
them.
24. The Set.-—The next process is to give them a
curved form, sometimes termed the set, which is done
on a three-legged stool, called a horse, the top of which
is a little larger than the tile, and is carved one way to
about a 10 feet radius. With the horse is used a
wooden block, curved to correspond with the surface of
the horse. These implements are used as follows : six
tiles are taken as last placed and put on this horse; the
man lifts up the wooden block and gives them three
sharp blows with it; they are then carried away and
placed in an ingeniously built wall to complete the
drying process (the wall built with the tiles to be dried),
after which they are carried to the oven, twelve at each
time, in a peculiar manner, with the edges of the tiles
against the breast of the carrier.
25. Quarries and dust bricks are moulded in like
manner from stiff clay, coal-dust being used to facilitate
the articles leaving the mould.
26. Drain Tiles.—Pipe drain tiles are made as foi-

ART OF MAKING BRICKS AND TILES.

109

lows: the clay is first moulded to the length, width,
and thickness required, and then wrapped round a
drum, the edges closed together by hand, the drum or
mandril turned round, and the pipe tile shaped by the
operator's hand, assisted in some cases by a wooden
tool: this is the mode of making pipe tiles from 3 in.
to 16 in. in diameter, whether cylindrical, tapered, or
egg-shaped.
The usual length is 18 in., and the diameter from
3 in. to 9 in. They are sold at Id. per in. bore; that is,
a pipe 3 in. in diameter and 18 in. long, would cost at
the yard Sd.; and a pipe 9 in. in diameter and 18 in.
long, 9d. This price applies to cylindrical pipes without
sockets.
27. Tile Machines.—One of Ainslie's machines has
been introduced into this neighbourhood, upon the
estate of the Duke of Sutherland, for making small
tubular drain tiles, which makes two pipes 1^ in. in
diameter at the same time. The prepared clay is forced
through two dods to form the tubes, which are cut into
lengths by wires affixed to the machine, and when
partially dry are rolled straight by hand upon a flat
surface, and then set up in racks to finish the drying
process.
28. Firing.—Firing the articles enumerated in the
previous description requires much more care than
firing bricks, and as roof tiles are the thinnest and
require most care, the largest sized pipe tiles excepted,
we shall describe firing an oven of such tiles.
On the bottom of the oven are first placed 2,000
bricks, as shown in fig. 13, and upon these are placed
7,000 tiles, forming a square, the spaces between the
tiles and the curved side of the oven being filled up
with bricks, as shown in fig. 14. The tiles are placed

110

RUDIMENTS OP THE

edgewise, in parcels of twelve, changing their direction
each parcel of twelve. The nibs on the tiles space them
off from each other, and support them in the vertical
position; from this description, and a reference to the
illustrations, it will appear, that the goods placed in the
oven are in each case so placed as to allow the diffusion
of heat between them; and as the uniformity of heat is
the desideratum in firing blue bricks and tiles, the
circular oven is found to answer better than any other
at present in use.
I t is necessary to have a wall round the outside of
the oven, about 6 ft. high, and at a distance therefrom
to allow the fireman space to attend his fires conveniently ; this wall is dry built generally with imperfect
bricks, and its use is to avoid one fire being urged more
than another by the set of the wind, which duty it
performs tolerably well.
The oven being set, the clammins (doorway) is made
up with bricks daubed over with street sweepings as a
loam; then the fires are kindled, and are kept slowly
burning for the first 5 hours, after which they are progressively increased for the next 3 3 / making 38 hours
for hard fired blue tiles or bricks; four tons of coal
being consamed in the firing. The heat is determined
by the sight of the fireman directed to the mouths and
top outlet of the oven. "When the heat is obtained, and
before the fires burn hollow, the mouths are stopped up
with ashes to prevent the currents of cold air passing
through the oven, which is then suffered to cool gradually. An oven is usually fired once a week, but may be
fired three times in a fortnight. After firing, twentyfour hours should be allowed for cooling before an oven
is opened to take out the tiles.
29. The following table shows the selling price per

ART OF MAKING BRICKS AND TILES.

Ill

1,000, and cost per superficial yard, of quarries, dust
bricks, and roof tiles :—
Size.

6 i n . so}.

7 „
9 „
9X4J
10 8X7 „

Price per
1,000.

35s.
46s.
80s.
40s.
25s.

Superficial mea- Price per
surement per superficial Thickness. Description.
yaid
1,000
in pence.
27-89 yards.
37*80
„
62-50
„
31-25
„
58 33
„

15-00
14-59
15-36
14-33
5-14

1 1 inch Quarries.
i I

2 „
I

2 J)

Bust bricks.
Roof tiles.

DESCRIPTION OF ILLUSTRATIONS.

30. Fig. 10. Isometrical View of a Bench for moulding
Tiles.

A. Coal-dust box, 14 in. by 8 in.
B. Moulding board, 14 in. by 10 in.
c. The bow.

31. Fig. 11. Elevation, showing the .Manner in which
the Tiles are placed during the last Drying.

d d. laths, two to each course.

112

BUDIMENTS OF THE

32. Fig. 12. Tile Block and Horse.

a. The block.

b. The horse.

c Tiles.

33. Fig. 13. Plan of Oven, as seen when eight courses
of Bricks are placed edgewise.

The eight rows of twelve bricks in each, as seen in plan, cover a space
left in continuation of flues from the eight fire-holes. The bricks in the
first seven courses are so placed as to leave a flue of an average width of
4 inches. The dotted Knes show the position of the fire-holes.

ART OF MAKING BRICKS AND TILES.

113

34. Fig. 14. Plan of Oven, as seen when the first course
of Tiles are placed upon the Bricks, as seen in
Ma. 13.

The tiles are placed in bungs of twelve, and laid alternately cross and
lengthwise, the nib spaces them off, and supports them in a vertical
position. Each side of the square is made up with bricks, as shown on
the plan.

35. The manufacture of bricks, &c, for building and
paving purposes, in a systematic manner, in suitable
premises with improved conveniences, so that the operatives may be employed the whole of the year instead of
a portion of it as now, is a subject deserving the attention of the capitalist and inventor. Improvements in
the quality and conveniences of this manufacture are
intimately connected with the moral, intellectual, and
physical condition of society, as may be seen by a visit
to any ordinary brickyard, and a reference to the
evidence before the Sanitary Commission. Where extensive supplies of marls or clay are found, suitable
works might be erected for such manufacture, could a

114

RUDIMENTS OF THE

cheap and ready mode of transportation be commanded,
so as to carry bricks, &c., a distance of 60 to 100 miles
without materially increasing their price.
36. Assuming the weight of bricks to be 3-| tons per
1,000, the present railway charges for the carriage of
bricks, viz. 2d. per ton per mile, if under 40 miles, and
lfd. per mile if more than 40 miles, would add to their
cost as follows :—
If carried under 40 miles .
Or for a distance of 39 miles
And if carried above 40 miles
Or for a distance of 60 miles

.
.
.
.

.
.
.
.

£ s.
0 0
1 2
0 0
1 10

d.
7 per 1,000 per mile.
9
6 per 1,000 per mile.
7

Therefore a carriage of 60 miles at the lowest railway
rate more than doubles the value of a common brick
compared with the price at the yard. The high rate of
charge for carriage, and the duty, which amounts to
nearly 22 per cent, of the selling price at the yard,
constitute obstacles to the improvement of the brick
manufacture, and the bettering of the condition of the
operatives employed therein. The recent improvements
in connection with domestic comfort and health, and
the encouragement offered to architectural improvements in the houses for artisans, may probably awaken
an interest in this department of industry, and place
even brickmaking in the position its importance
deserves, if not demands.

87. ANALYSES OF

CLAYS, ETC.

Dun coloured marl,
burns good blue.

Top yellow marl,
burns reddish blue.

Mingled marl,
burns blue reddish.

Rotten red marl,
will not stand the
heat; it melts.

Mixture of clays,
Nos. 1, 2, 3, and 4,
burns good blue.

Clay from Stokeupon-Trent. burns
red, and will not
burn blue.

dagger marl, burns
light buff—a firebrick.

1

2

3

4

5

6

7

8

6987
16-79
8-88

64-32
20-33
10-86

65-78
15 16
8-49

70*17
16-25
8.41

42-84
1761
697

59-44
25-93
1074

60-02
2426
9-14

54.38
26-55

1*29

1536
11.61
2-20

(

Red marl, which
burns blue.

|

TABLE 1.—ANALYSIS OP CLAYS, NOS. 1, 2, 3, 4, 5 and 6, from Basford ; 7 and 8 from the Staffordshire Potteries.
By F. C. WEIGHTSON, Esq., Birmingham.

Peroxide of iron, with a little protoxide
Protoxide of iron, with a little peroxide

838

Trace.
Soda and a little potash

* ... .

Trace.

1-67

4-26
99-80

6-60
102-11

537
96-47

.. .
5-86
101*98

1-60
3*14
Trace.

3-94

3'11

Trace.
1-40
3-89

100.53

99.22

100-31

7-23
99-73

TABLE 2.—The Clays in Table 1 arranged in the order of infusibility, beginning with the most easily fusible clay,
and calling that No. 1.

1

No.

Number of Analysis in Table 1

.

.

2

3

4

5

42-84
5

54-38
8

59-44
6

60-11
7

64-32
2

6 '
65*78
3

7

8

69*87
1

70-17
4

TABLE 3.—The Clays in Table 1 arranged in the order of intensity of colour, beginning with the lightest shade.
Number of Analysis in Table 1

. .

8
about !•

i

5

4

6-97

8-41

3

8-49

1

7*

8*88

9-14

6

2

10-74

10-86

* Will not burn blue, burns red,
TABLE 4.—Showing the different proportions of bases contained in the Clays in Table 1.
Number of Analysis in Table 1 . .
Alumina and other bases equivalent .

5

7

50-91 1 35-18

6

8

2

3

4

32-93

32-65-

2733

23-66

23*65

1
22-59 1

£
Ca

ART OF MAKING BRICKS AND TIL£S.

117

No. 5, Table 1, contains 42*84 per cent, silicic acid;
this requires, theoretically, 47*60 of alumina, or its
chemical equivalent in other bases, to form a fusible
compound ; it therefore contains only 3*31 per cent,
excess of base. This is insufficient to prevent its fusion
—a much larger excess would. No. 1 contains 22*59
of base, which requires 25*1 of silicic acid, therefore
69*87 — 25*10 = 44*77 the excess of silicic acid, or
uncombined silica in the clay, rendering it infusible.
ANALYSIS of COAL, called NORTON COAL, used in the
potteries for burning pottery and bricks :—
Carbon
Hydrogen
Oxygen
Sulphur
Nitrogen .
Ash

.

.

.

.

81*08
5*04
10-55
0*36
. Trace.
2-97
100-00

ANALYSIS of a porous substance which floats in water.
I t is a piece of a vitrified fort from Connel Ferry, near
Dunstaffnage Castle, Scotland:—
Alumina and peroxide of iron 28*45^
Silica
67*85 '
Lime
0*32
Manganese . . . .
Trace.
"Water
.
.
.
.1*88

This specimen has the appearance of pumice-stone. It is
only very slightly fusible even
in the very highest temperature
of the blow-pipe.

98-50;

BRICKMAKTNG ON THE SOUTH STAFFORDSHIRE RAILWAY.

38. The following additional particulars respecting
brickmaking in Staffordshire were sent to the author
of this volume by Mr. J. L. Brown, of Farewell, near
Lichfield, and are given in his own words :—

118

RUDIMENTS OF T H E

" The brickyard I visited is on the highway from
Lichfield to Walsall, at a place called Walsall Wood;
it is worked by Mr. George Brown, of the Sand Hills,
near that place. Mr. B. has another brickyard in the
neighbourhood, more extensive than the one I visited,
and from these brickyards have been supplied all the
bricks used for building the bridges, viaducts, cattlearches, culverts, &c, &c, on the South Staffordshire
Junction Railway.
" The brickyard I visited has six kilns or cupolas, and
three large moulding and drying-sheds for use in the
winter season, each 40 yards long by 8 yards wide,
having fire-places at one end, and traversed by flues,
longitudinally, to a chimney at the other end.
" The material used is not a clay^ but a friable kind
of marl. The first stratum under the surface soil is
about 4 ft. thick, very compact in body, and requires
the pick to get it; it is of a purplish hue. This is succeeded by a stratum, 3 ft. thick, of bright yellow-looking
marl, equally intermixed with marl, of a bright scarlet
colour, and afterwards, down to the depth of 20 ft., the
purple-coloured marl comes in again.
" The earth in its raw state is drawn up an inclined
plane on a common railway truck, by a steam-engine
of 20-horse power, and at the top of the incline it tips
itself into a hopper placed over the cast-iron rollers,
between which the marl passes and comes down an
inclined board, after being ground quite small. It is
afterwards wheeled into heaps and tempered, and is
then wheeled up an inclined plane of earth to the enginehouse, where it is passed through vertical cylinders of
cast iron, in the centres of which are revolving pistons
armed with flanges, like the screw propeller of a steam
vessel, which grind the tempered clay and force it

ART OF MAKING BRICKS AND TILES.

119

through holes in the bottoms of the cylinders to
chambers beneath them, whence it is wheeled to the
moulders.
" They make red and blue bricks of the same marl,
prepared in each case by rolling and grinding. To
make the blue bricks, they keep the fires very much
sharper and hotter, which changes their colour, and
seems to run or fuse the material more, giving them at
the same time a shining appearance. They make very
few red bricks.
" The price of the best bricks at the kiln is 30s. per
1,000; common bricks, 25s. per 1,000. Plain-tiles
for roofing, 28s. to 32s. per 1,000. They also make
chimney-pots, pipes for the conveyance of water, splayed
bricks, coping bricks, and bricks to any-model."

CHAPTER ^v
BEICKMAKING IN THE VICINITY OF LONDON.

1. FOR facility of reference, we propose to divide the
subject under three heads, as follows :—
1st. Materials and Plant.
2nd. Process of Manufacture.
3rd. Cost of Manufacture.
1. MATERIALS AND PLANT.

2. Brick-earth.—The brickmakers in the vicinity of
London at present derive their principal supplies of
brick-earth from the alluvial deposits lying above the
London clay, the blue clay not being used for brickmaking at the present day. The general character of

120

RUDIMENTS OF THE

the brick-earth may be described as being a gravelly
loam, passing by fine gradations into either a strong
clay or into marl, or, as it is technically called, malm,an
earth containing a considerable quantity of chalk in fine
particles. "We may, therefore, for the purpose of description, class the several qualities of brick-earth under three
heads, as follows :* strong clay, loam, and malm.
3. 1st. Strong Clay.—This is generally sufficiently
free from stones to be used without washing, and the
bricks made from it are hard and sound, but are liable
to crack and contract very considerably in drying, and
become warped and misshapen in burning. These defects are in a great measure removed by mixing the
earth with chalk, reduced to the consistency of cream,
as will be presently described, which greatly diminishes
the contraction of the clay, and improves the colour of
the brick.
4. 2nd. Loam.—The loams are often so full of gravel
that it is impossible to free them from stones, except by
passing the earth through the wash-mill. The quantity
of sand present in these earths renders them less liable
to shrink and warp than the strong clays; but, on the
other hand, the texture of the earth is so loose and incoherent, that a mixture of chalk is necessary to bind
the mass together, and to take up the excess of fusing
silica in the process of burning.
5. 3rd. Malm.—This is an earth suitable for making
bricks, without any addition, but there is very little now
to be had, and for making the best qualities of bricks
(or, as they are called, malms) an artificial malm is made,
* It may be observed that this classification is such as would be best
understood by the generality of readers, but would not be comprehended
by most brickmakers, who class these three qualities of brick-earths as
strong clay, mild clay, and malm. When the clays are strong, they are
said, in brickmakers' language, to htfoul.

ART OF MAKING BRICKS AND TILES.

121

by mixing together chalk and clay, previously reduced
to pulp in wash-mills. This pulp is run off into shallow
pits, where it remains until, by evaporation and settlement, it has become of sufficient consistency for subsequent operations. This process is adopted for the best
qualities of bricks only, as the expense of it is very considerable ; and, for the commoner sorts, all fchat is done
is, to mix with the loam or clay a sufficient quantity of
malm to make it suitable for brickmaking: the quantity of malm required for this purpose varies, of course,
according to the quality of the earth.
6. It will be readily understood, from the above
remarks, that the mode of preparing the clay differs
greatly in different yards. The brick-earth (according
to its quality) being used—
1st. Without either washing or maiming,
2nd. It may be maimed, i.e., covered with artificial
malm.
3rd, and lastly. The bricks may be made entirely of
malm.
The second process is the most common, and we propose, therefore, in the following pages, to describe the
successive operations of brickmaking as practised at
those works where the loamy character of the earth
renders the maiming indispensable. This will enable
the reader to understand the first and third methods of
treating the brick-earth without any further description.
7. The object of adding chalk to the clay is twofold.
In the first place it acts mechanically, in diminishing
the contraction of the raw brick before burning; and
in the second place it acts chemically, as a flux during
the burning, combining with the silica of the clay, so
that a well-burnt London brick may be described as
a silicate of lime and alumina, and, therefore, differs
G

122

RUDIMENTS OF T H E

greatly from an ordinary red kiln-burnt brick made of
pure clay, without lime or alkaline matter, the silica
and alumina of the brick-earth being, in the latter case,
merely in mechanical and not chemical combination.
8. Soil.—The process of maiming is not the only
peculiarity of London brickmaking. Instead of the
bricks being burnt in close kilns, as is the practice in
most country yards, " clamping" is universally resorted
t o ; and to render this effective, it is considered necessary that the fuel should be mixed up with the brickearth, so that each hrick forms, as it were, a fire ball,
and becomes thproughly burnt throughout, instead of
l?eing merely baked, as is the case in kiln burning. The
fuel used in clamp burning is domestic ashes, or, as they
are technically called, breeze. The ashes are collected
in large heaps, and sifted; the sittings, which are called
soil, being mixed with the brick-earth, and thoroughly
incorporated with it in the processes of soiling and
" tempering," whilst the cinders, or " breeze," are used
as fuel. A small quantity of coal and wood is also
made use of in lighting the clamp.
The soil, or sifted ashes, materially assists in preventing the contraction of the raw bricks whilst drying,
and the sulphur contained therein appears to assist in
colouring the bricks when burnt,
9. Sand.—The moulding sand is brought, at a considerable expense, from the bed of the river Thames,
near Woolwich, It is spread out to dry in the sun in
thin layers, which are repeatedly raked over, so as to
expose every particle in succession to the sun's rays,
that the whole may be perfectly dry when brought to
the moulding stool. The moulding sand serves many
useful purposes. It assists in preventing the contraction of the clay, and gives a more durable surface to the
bricks. It is indispensable to the moulder for pre-

ART OF MAKING BRICKS AND TILES.

123

venting the bricks from sticking to his mould. It also
prevents the bricks from sticking together on the hacks,
and from breaking up into cracks and flaws when cooling, after being burnt. Lastly, the salt in the river
sand becomes decomposed in the burning, and assists
in fluxing the brick-earth, and in giving the bricks their
grey colour. Common sand burns of a red tint, and
would injure the colour of the London bricks.
10. General Arrangement of a Brickwork.—This will
be readily understood by reference to fig. 1. The brickearth is turned over to receive the malm as near as
possible to the clay pits.. The clay and chalk mills are
placed close together in some convenient position, so
as to interfere with the works as little as can be helped,
and the malm is conveyed from them to the heap of
brick-earth, by means of troughs or shopts supported
on tressels.
Close to the brick-earth, and immediately behind the
moulding stool is placed the pug-mill, and in front of
the moulding stool is the hack ground, which should, if
possible, be laid out with a gentle fall towards the
clamps, which is placed at its furthest extremity.
These arrangements are of course much modified by the
circumstances of the locality.
11. The Chalk and Clay Mills.—These washingmills are placed close together on a large double mound,
sufficiently elevated to allow the malm to run down
freely to the brick-earth. The chalk-mill is a circular
trough lined with brickwork, in which the chalk is
ground by the action of two heavy wheels with spiked
tires, made to revolve by either one or two horses. The
trough is supplied with water by a pump, the lever of
which is worked by the machinery of the clay-mill, and
as the chalk becomes ground into pulp it passes, by
G 2

124

RUDIMENTS OF THE

Fig. L

Mllflfl flflfl

^i^WKiM

Anr

or MAKING BRICKS AND TILES.

125

means of a shoot, into the clay-mill. The clay-mill is
also a circular trough, lined with brickwork, but much,
larger than that of the chalk-mill; and in this trough
the clay is mixed with the pulp from the chalk-mill, and
is cut and stirred by knives and harrows put in motion
by two horses, until the whole mass is reduced to the
consistency of cream, when it passes off through a brass
grating into the troughs or shoots, and is conducted to
the brick earth which has been heaped up to receive it.
The machinery of the washing*mills is very fully delineated in figs. 2 to 10, and is described in detail in
arts. 53 and 54.
12. The Pug-mill.—The pug-mill used in brickmaking is a conical tub, with its larger end uppermost,
in the centre of which is a revolving vertical shaft of
iron, to which are attached horizontal knives, inclined
so that the clay is slowly forced downwards by their
motion. The top and bottom knives are called force
knives, and their use is merely to force the earth
through the mill, and out at the ejectment hole; all the
other knives are furnished with cross knives, which
assist in cutting the clay, and breaking up any hard
lumps that may not have been broken up by the previous
wintering and turning over. In order to feed the mill,
an inclined barrow-run is laid up to it, to enable the
wheeler to tip the clay in at the top.
The construction of the pug-mill is shown in figs. 11
and 12.
13. The Cuckhold, fig. 13, is an instrument for
cutting off lumps of the tempered clay for the use of
the moulder, as it is ejected from the pug-mill, and
requires no particular description.
14. The Moulding Stool.—The moulding stool is
quite different from that used in most parts of the

12.6

RUDIMENTS OF THE

Figs. 2 and 3.

26 fi-

country. I t has a rim at each end, to keep the moulding
sand from falling off, and is provided with a stock-board,
which forms the bottom of the brick mould, and with a

ART OF MAKING BRICKS AND TILES.

127

Figs. 4 and 5.

S

_

Wpr

page, which is formed with two rods of f iron, nailed
down at each end to the wooden rails on which they
rest. The use of the page is to slide the raw bricks
more readily from the moulder to the place from whence
they are taken and put upon the hack barrow by the
" taking-off" boy. The moulder, when at work, stands

128

RUDIMENTS OF THE

Mg. 6.

m

IQ

(5

20

near the middle of the stool, with the page on his left
hand, and his assistant, the clot-moulder, on his right.

ART OF MAKING BRICKS AND TILES.

129

ity.6.

zof

The moulding sand for the use of the moulder and clotmoulder is placed in separate heaps at the opposite ends
G 3

RUDIMENTS OF T H E

Fig.l,

ART OF MAKING BRICKS AND TILES*

131

7.8.

6

H '=s

• '

£
^ ^ ?p-%

7> s

4r
Mgs. 9 and 10.

/f=\

/r=v

of the stool, and the tempered clay nearly opposite to
the moulder. There is no water-box, but a tub is placed

132

RUDIMENTS OF T H E

Fig. 11.

on the stool, into which the strike is thrown when not
in use. The pallets are placed at one end of the page.

ABT OF MAKING BRICKS AND TILES.

Fig. 12.

183

i34

RUDIMENTS OF THE

Fig. 13.

and close to the moulder's left hand. These particulars
will be fully understood by reference to fig. 13, and to
the detailed description in art. 56,

ART OF MAKING BRICKS AND TILES

135

15. The Brick Mould is made of sheet iron, in four
pieces, riveted together at the angles, and strengthened
with wood at the sides only. The bottom of the mould
is detached, and forms what is called the Stock-board.
See fig. 14.
Mg. 14

,

a

6

§

&f

16. The Stock-board is a piece of woc-d plated with
iron round the upper edge, and made to fit the mould

136

RUDIMENTS Of THE

accurately, t u t easily. At each corner an iron pin is
driven into the moulding stool; and on these pins the
bottom of the mould rests, the thickness of the brick
being regulated by the distance to which the pins are
driven below the top of the stock aboard. The hollow
in the bed of the brick is produced by a rectangular
piece of wood, called a kick, of the size and shape of the
hollow required, which is fastened on the upper side of
the stock-board.
17. The Strike is a smooth piece of wood, about
10 in. long by 1^ in* wide and ^ in. thick, and is used
to remove the superfluous clay in the process of
moulding.
The Pallets are pieces of board f in. thick, and of
the exact width of the mould, but about f in. longer.
Three sets of pallets, twenty^-six in each set, are required for each moulder at work.
18. The Hack Barrow, figs. 15 and 16, is of a peculiar construction. It consists of a light frame, supporting a flat top of lattice work, on which the bricks
are placed in two parallel rows, thirteen in each row.
Three barrows are required for each moulder.
19. The Hack Ground occupies the space between
the moulding stool and the clamp. I t should be well
drained, and it is desirable that it should be on a slight
fall towards the clamp, as this lessens the labour of
wheeling* The foundations of the hacks are slightly
raised. It is of importance that the barrow-runs between the hacks should be perfectly even, as any jolting
of the hack barrow would injure the shape of the raw
bricks, which, when first turned out of the mould, are
very soft. The hacks are placed 11 ft. apart, measured
from centre to centre, their length varying according to
the shape of the ground. It is very difficult to say

ART OF MAKING BRICKS AND TILES.

187

Mg. 15.

what extent of hack ground should be allotted to each
moulding stool, as this varies greatly in different yards.
In round numbers, the quantity of land required for a
brickwork may be stated at from \\ to 2 acres for each

138

RUDIMENTS OF THE

Fig. 16.

moulding stool, but this includes the whole of the land
required for the several purposes.
II—PROCESS OF MANUFACTURED

20. Clay Digging.—The. first turning over of the
brick-earth should take place in the autuniii, in order
that it may have the benefit of the winter frosts before

ART OF MAKING BRICKS AND TILES.

139

being used. The vegetable mould and top soil having
been wheeled to spoil, the brick-earth is turned up three
or four spits deep, and laid on a level floor, prepared for
the purpose, and banked round to prevent the escape of
the malm in the process of maiming.
21. The quantity of clay required per 1^000 bricks is
variable, of strong clay more being required than of
milder qualities.
It is generally calculated that an acre 1 ft. deep, or
about 1,600 cubic yards of clay, will make 1,000,000
bricks, but strong clays will require from 182 to 200
cubic yards per 100,000 bricks. For practical purposes,
the quantity may be thus approximately stated:—
Strong clay 2 cubic yards per 1,000 bricks.
Mild clay If cubic yard per 1,000 bricks.
22. Maiming.—It has been before explained that the
best bricks only ar.e made entirely of malm, but that the
process of maiming is resorted to for other descriptions
of bricks, where the quality of the clay renders it unfit
for brickmaking without this addition. It will, therefore,
be readily understood that the quantity of malm mixed
with the clay in the ordinary process of brickmaking
varies very considerably, so that it is impossible to
say, a priori, what quantity of malm should be used, as
this must be left to the judgment of the brickmaker in
each particular case, according to the quality of the
earth.
To keep the washing, mills in full work are required—
To the chalk^mill, 2 diggers and 1 wheeler.
To the clay-mill, 4 diggers and 2 wheelers.
The chalk-mill is worked sometimes with one, and
sometimes with two horses. The clay-mill always requires two horses. No drivers are required.

140

UtTDIMEOTS OF THE

The average work of the washing-mills, working 10
hours a day, may be taken at about 12 cubic yards of
malm,* or sufficient for making 6,000 malm bricks.
The process of maiming scarcely requires description*
Water having been pumped into the troughs, chalk is
wheeled to the chalk-mill, and clay to the clay-mill,
and the horses being driven round, the chalk is crushed
and ground by the wheels, and runs through the outlet
into the clay-mill, where both chalk and clay get well
mixed by the harrows, the liquid malm flowing out
through the brass grating to the shoots, by which it is
conducted to the brick-earth. As the heap becomes
covered the shoots are shifted, so. that the malm shall
be equally distributed over every part of the heap.
When a sufficient quantity of malm has been run off,
it is left to settle for a month or more, until it has
become sufficiently consolidated to bear a man walking
over it. As the solid portion of the malm settles, the
water is drained off from time to time, and when the
mass is sufficiently firm, the soiling is proceeded
with.
23. Soiling.—The proportion of ashes depends very
much on the quality of the earth, but may be stated
approximately at about 35 chaldrons for every 100,000
bricks. The soil is laid on the top of the maimed earth,
the thickness of the layer depending on that of the
heap, about 3 in. of ashes being allowed for every spit
of earth.
The soiling concludes the preparation of the brick,
earth, which is allowed to remain undisturbed until the
* At a manufactory of artificial hydraulic lime at Meudon,near Paris,
the chalk and clay are ground together in a washing-mill, of the same
construction as those used in England, and worked by two horses. The
quantity of malm produced is about 1 | cubic j-ard per hour.—See Vicat
on Cements.

AItT OF MAKING BRICKS AND TILES,

141

moulding season, which generally commences in April,
The first process of the actual manufacture is—
24. Tempering.—The heap, prepared as above, is
turned over by spade labour, and the ashes thoroughly
incorporated with it, water being added to bring the
mass to a proper consistency. The tempered clay is
then wheeled to the pug-mill, which, as before stated, is
placed close to the clay heap, and immediately behind
the moulding-stool.
25. Pugging.—The tempered clay being thrown in
at the top of the mill, gradually passes through it, and
in so doing becomes so thoroughly kneaded as to be of
a uniform colour, the ashes being equally distributed
through the mass. The quantity of clay ground is
about 14 cubic yard per hour, so that a horse working
10 hours per diem will grind \2\ cubic yards of clay,
or sufficient to make 6,250 bricks.
If the moulding process does not proceed as fast as
the pugging, so that the clay will not be immediately
used, the clay, as it comes out at the bottom of the
mill, is removed with the cuckhold, and covered with
sacks, to keep it from becoming too dry for use.
26. Moulding.—Before commencing moulding, the
moulding-stool is provided with two heaps of dry sand,
a tub of water, in which to place the strike, a stockboard and brick-mould, and three sets of pallets.
Everything being in readiness, and a supply of tempered clay having been placed on the stool by the feeder,
whose business it is to carry the tempered clay from the
pug-mill to the moulding-stool, the clot-moulder> who
is generally a woman, sprinkles the stool with dry sand,
and taking a clod, or clot, from the heap of tempered
clay, dexterously kneads and moulds it roughly into the
shape of a brick, and passes it to the moulder on her

142

RUDIMENTS Ol T#T2

left hand. The moulder, having sprinkled sand on the
stock-board, and dashed the mould into the sand-heap
on his left hand, places the mould on the stock-board,
and dashes the clot into it with force, pressing it with
his fingers, so as to force the clay into the angles of
the mould. He then, with the strike, which has been
well wetted in the water-tub, removes the superfluous
clay, which he throws back to the clot-moulder to be
remoulded. The mould is then lifted off the stockboard, and placed by the moulder against one of the
pallets, which he catches dexterously with his fingers,
and, turning out the raw brick upon it, slides it along
the page to the taking-off boy, and, lifting up the
empty mould, dashes it into the sand, and replaces it
on the stock-board, preparatory to moulding a second
brick; when he has moulded one set of bricks, he
scrapes away the sand which has adhered to the mould
during the operation with the strike, and then proceeds
with the next set. A moulder and clot-moulder, with
the assistance of a feeder, a taking-off boy, and two
men to wheel and hack the bricks, will make about
5,000 bricks between 6 A.M. and 6 P.M.; but this;
quantity is often exceeded.*
27. Hacking,—The raw brick is removed from the
page by the taking-off boy and placed on the hack
barrow, and when the latter is loaded, dry sand is
sprinkled over the bricks, and they are carefully
wheeled away to the hack ground. Having arrived at;
that part of the ground where the hack is to be commenced, the man takes a spare pallet and places it on
* See the following:—" Brickmaking. On Wednesday last, Jos. Rush#
at Peterskye, Cumberland, performed the feat of making 1,000 bricks irt
an hour; 100 in five minutes ; and 26 in one minute."—Carlisle Journal*
(This is not a solitary instance.)

ART OF MAKING BRICKS AND TILES

143

oiie of the bricks, which he carries between the two
pallets to the ground, and sets it up carefully edgeways,
taking care in removing the pallets not to injure the
shape of the soft brick. One of the pallets is replaced
on the barrow, and with the other another brick is
removed; and the process is repeated till the twenty-six
bricks have been placed on the ground, when the empty
barrow is wheeled back to the moulding stool. In the
meantime another barrow has been loaded, and is ready
for wheeling to the hack ground. Three hack barrows
are required, so that one of them is constantly being
unloaded upon the hack ground, another loading at the
moulding stool, and the third being wheeled to or from
the hack ground. Thus two men are necessarily employed in the operations of wheeling and hacking. The
hacks are set up two bricks in width, the bricks being
placed slantwise, and not at right angles, to the length
of the hack. After the bottom row of one hack is completed, a seoond hack is commenced, to give the bricks
time to harden before a second course is laid on them;
and when the second course is commenced, the bricks
must be placed fairly on each other, or they will be
marked, which injures their appearance. The hacks
are carried up in this way until they are 8 bricks
high, when they are left for a few days to harden. To
protect the new bricks from frost, wet, or intense heat,
straw or reeds are provided and laid alongside the hack,
and with these the bricks are carefully covered up at
night, and at such other times as the weather may
render necessary. When half dry, they are scintled,*
that is, set farther apart, to allow the wind to pass
freely between them, and they receive no further attention until sufficiently dry for burning. The time
* Literally, scattered.

144

RUDIMENTS OF THE

required for drying varies from three to six weeks,
according to the weather.*
28. Clamping,—Figures 17, 18,19, 20, and 21. The
process of clamping requires great skill, and its practical details are little understood, except by the workmen engaged in this part of the manufacture. Scarcely
any two clamps are built exactly alike, the differences
in the methods employed arising from the greater skill
or carelessness of the workmen, and local circumstances,
such as the situation of the clamp, and the abundance
or scarcity of burnt bricks in the yard with which to
form the foundation and the outside casing. We propose, therefore, first to describe the method of building
a clamp, according to the most approved system, and
then to explain the principal variations practised in
different yards,
29. A clamp consists of a number of walls or necks,
3 bricks thick, about 60 bricks long, and 24 to 30 bricks
high, in an inclined position on each side of an upright
or double battering wall in the centre of the clamp, the
upright being of the same length and height as the
necks, but diminishing from 6 bricks thick at bottom
to 3 bricks thick at top. The sides and top of the
* Mr. H. Chamberlain, in a paper read before the Society of Arts, IV.
515, speaks of the great importance of drying bricks :—" The drying of
bricks ready for burning is a matter of great importance, and requires
more attention than it generally receives. From hand-made bricks we
have to evaporate some 25 per cent, of water before it is safe to burn
Ihem. In a work requiring the make of 20,000 bricks per day, we have
to evaporate more than 20 tons of water every 24 hours. Hand-made
bricks iose in drying about one-fourth of their weight, and in drying and
burning about one-third. The average of machine bricks—those made
of the stiff plastic clay -4o not lose more than half the above amount
from evaporation, and are, therefore, of muck ^r*;ater specific gravity
than hand-made ones." The artificial drying of bricks over flues can of
course only be carried on where coal is cheap. Mr. Beart has contrived
a steam chamber, where steam made to circulate in pipes is the source of
heat for drying the bricks.

ART OF MAKING BRICKS AND TILES.

Fig. 17.

145

*

'81 *%

anax &o sxraHiaxrH

ART OF MAKING BRICKS AND TILES.
Fig. 20.

THE LIVE-HOLE

Fig. 19.
H 2

(c)

147

148

RUDIMENTS OF T H E

% . 21.

ART OF MAKING BRICKS AND TILES.

,

149

clamp are cased with burnt brick. The fuel used in
burning the laid bricks consists of cinders (breeze, as
before described), which are distributed in layers between
the courses of bricks, the strata of breeze being thickest
at the bottom. To light the clamp, live holes or flues,
7 in. wide and 9 in. high, are left in the centre of the
upright, and at every 7th or neck. These live holes
extend through the whole thickness of the clamp, and
are filled with faggots, which, being lighted from the
outside, soon ignite the adjacent breeze. As soon as
the clamp is fairly lighted, the mouths of the live holes
are stopped, and the clamp burns until the whole of the
breeze is consumed, which takes from three to six
weeks. This description will give the reader a general
idea of the arrangement of a clamp; and we will now
describe in detail the manner of building one, premising
that the term close bolting signifies stacking bricks so
that they shall be perfectly close to each other; and
that scintling means stacking bricks with spaces between them.
30. Foundation.—The ground is first carefully drained
and levelled, and made perfectly firm and hard. The
exact position of the clamp having been fixed, the
ground is formed with a flat invert whose chord is
equal to the width of the intended clamp. The object
of this is to give a lift to each side of the clamp, which
prevents the bricks from falling outwards as the breeze
becomes consumed. The ground being prepared, the
upright is commenced. But, previous to building, the
clamp barrow-roads or tramways of sheet-iron are laid
down between the hacks, and extended to the clamp
ground, to give an easy motion to the barrows; as, from
the kind of barrows used in clamping, the bricks being
piled on each other several courses high, and the

150

RUDIMENTS OF THE

wheeling carried on with considerable velocity, they are
apt to upset.
31. Upright.—The upright is commenced by building
two 9 inch battering walls about 45 ft. apart, of burnt
bricks laid on edge, which are termed close bolts, the
length of each wall being equal to the thickness of the
upright, which at the bottom is 6 bricks thick, or about
4 ft. 6 in. (their height is 16 courses, or about 6 ft.).
Between these bolts a line is stretched, by which the
upright is built true. The ground between the bolts is
paved with burnt bricks laid on edge, to exclude the
moisture of the ground. Upon this paving are laid
two courses of burnt bricks with spaces between them,
termed scintles. In the bottom course of scintles the
bricks are laid diagonally about 2 in. apart. The
second course consists of burnt bricks on edge, laid
across the lower one, in lines parallel to the ends of the
clamp, and also 2 in. apart. Inlaying these two courses
of scintles, a live hole is left about 7 in. wide, the whole
length of the upright; and, on the completion of the
second course, the live hole is filled up with faggots, and
the whole surface covered over with breeze, which is
swept or scraped into the spaces left between the bricks.
On this surface is placed the first course of raw bricks,
laid on edge and quite close, beginning over the livehole. Over this first course of raw bricks is laid a
stratum of breeze 7 in. thick, the depth being increased,
at the ends of the uprights, to 9 or 10 inches, by inserting
three or four bricks on edge among the breeze. The
object of this is to give an extra lift to the ends. The
first course of bricks, it should be observed, is laid all
headers. Over the first layer of breeze is laid a second
course of raw bricks on edge, all stretchers. This is
covered with 4 in. of breeze, and at each end are inserted

ART OF MAKING BRICKS AND TILES.

151

two or three bricks to increase the lift still more; but this
time they are laid flat, not edgeways. Upon the, 4 in.
layer of breeze is laid a heading course of raw bricks laid
close, and on this 2 in. of breeze, without any extra lift at
the end. To this succeed stretching and heading courses
of raw bricks on edge, laid close up to the top of the
clamp, a layer of breeze, not more than f in. thick, being
placed on the top of each course, except on the top
course, which has 3 in. of breeze. The top of the upright is finished by a close bolt of burnt bricks. The
upright is built with an equal batter on each side, its
width diminishing from six bricks lengthways at the
base to three bricks lengthways at the top. In order
that the upright should be perfectly firm, it is necessary
that the bricks should be well tied in at the angles;
and, in order to obtain the proper width, the bricks
are placed in a variety of positions, so that no very
regular bond is preserved, as it is of more consequence
to keep the batter uniform.
The close bolts first commenced, and which form the
outer casing of the clamp, are not built close to the raw
bricks, there being a small space left between the clamp
and the close bolting, which is filled up with breeze.
The close bolts, however, are built with a greater batter
than the ends of the upright, so that they just touch the
latter at the 16th course, above which the clamp is built
without any external casing. When, however, the upright is topped, and whilst the top close bolting is going
on, the casing is continued up to the top of the clamp.
This upper casing is called the bestowing, and consists
of five or six courses of burnt brick laid flat, forming a
casing 4 j in. or half a brick thick; and above the 6th
course the bricks are laid on edge, forming a still
thinner casing only 3 in. thick. When the weather is

152

RUDIMENTS OP THE

bad, and during the latter part of the brickmaking
season, a little extra bestowing is given beyond what is
here described. The great art in clamping consists in
the proper construction of the upright, as the stability
of the clamp depends entirely upon it.
32. Necks.—The remainder of the clamp consists of
a number of necks or walls leaning against the upright.
They are built in precisely the same way as the upright,
as regards invert, close bolts, paving, scintling, breeze,
and end lifts. But there is this essential difference, viz.,
that they are parallel walls, built in alternate courses of
headers and stretchers laid on edge, each heading course
in one neck being opposite to a stretching course in the
next neck, and vice versa. The thickness of each, neck
is made up of three bricks lengthways in the heading
courses, and ten bricks edgeways in the stretching
courses. The necks are close bolted at top, and bestowed in the same manner as the upright. When the
last necks have been built, the ends of the clamp are
close bolted, and bestowed in the same way as the sides,
and this operation completes the clamp.
33. Firing.—The number of necks on each side of
the upright may be extended to eight or nine, without
an additional live hole; but if this limit be exceeded,
additional live holes are required, according to the
judgment of the brickmaker or the demand for bricks,
the live holes are placed seven, eight, or nine necks
apart. It is not necessary that the additional live holes
should pass under the centres of the necks, and it is
more convenient to form each live hole so that the face
of the last-built neck shall form one of its sides.
In the close bolting surrounding the clamp, two bricks
are left out opposite the end of each live hole, and to
each of these openings a fire is applied made of coals,

ART OP MAKING BRICKS AND TILES.

153

and wood heaped up in a brick fire-place built round
the opening, and known by the name of a devil-stove.
The fire is kept up for about a day, until the faggots in
the live hole are thoroughly ignited, and as soon as this
is found to be the case, the fire is removed, and the
mouth of the live hole stopped with bricks, and plastered
over with clay. I n firing a large clamp with many live
holes, it should be begun at one end only, the live holes
being fired in succession, one after the other.
The bricks at the outside of the clamp are underburnt; they are called burnovers, and are laid aside
for reburning in the next clamp that may be built.
The bricks near the live holes are generally partially
melted and run together in masses called clinkers or
burrs. The bricks which are not fully burnt are called
place bricks, and are sold at a low price, being unfit for
outside work, or situations where they will be subjected
to much pressure. The clinkers are sold by the cartload, for rockwork in gardens and similar purposes.
34. The quantity of breeze required varies much with
the quality of the earth. The usual proportions for
every 100,000 bricks are about 35 chaldrons of the sifted
ashes, mixed with the brick-earth, and about 12 chaldrons of the cinders or breeze to light the clamp.
The quantity of fuel to the live holes it is difficult to
calculate; about 10$. may be taken as the average cost
of coals and wood for every 100,000 bricks.
35. If the proportion of breeze be too small, the
bricks will be underburned, and will be tender and of
a pale colour. If too much fuel be used, there is danger
of the bricks fusing and running into a blackish slag.
No rules can be laid down for avoiding these errors,
as the management of the breeze must depend upon the
quality of the earth, and can only be learnt from
H 3

154

RUDIMENTS 0!F THl

experience, some brick-earths being much more fusible
than others.
36. The time of burning varies considerably. If expedition is requisite, the flues are placed near together,
and the burning may be completed in a fortnight or
three weeks; but, if time is no object, the flues are
further apart, and the clamp is allowed to burn off more
slowly.
37. Another system of clamping is to begin at one
end and to follow with the necks in one direction only.
This is done when the clamp ground is partly occupied
by the hacks, so as to render it impossible to commence
at the centre. When this system is adopted, the clamping begins with the erection of an end-wall, termed the
upright and outside, which is made to batter very considerably on the outside, but of which the inside face is
vertical. As regards dimensions and modes of building,
the outside and upright is built in the same way as the
ordinary upright, but it has, of course, no live hole under
it, the first live hole being provided in the centre of the
2nd or 3rd neck. In the style of clamping the necks
are all upright. The live holes are placed at every 8th
or 9th neck, as in the usual system.
38. "We now proceed to describe the principal variations in the methods of clamping practised in different
brick-yards.
Paving.—The practice with regard to the paving of
burnt bricks is very variable. Some clampers omit it
altogether; others pave only where clamping for the first
time on a new clamp ground.
Scintles.—When burnt bricks run short, as in building the first clamp on a new ground, the second course
is laid with raw bricks. This, however, is a very objectionable practice.

ART OF MAKING BRICKS AND TILES,

155

Live Soles.—The live holes are sometimes closebolted at the sides, to prevent the breeze from the
scintles falling into them. This, however, is not often
done, and its utility is questionable.
Breeze.—Some clampers put the 7 in. stratum of
breeze on the top of the scintles, instead of placing it
over the 1st course of raw bricks; very frequently the
breeze is dispensed with after the 2 in. stratum, with
the exception of the top layer. All clampers, however,
agree as to the necessity of having the 7 in., 4 in., and
2 in. layers.
39. The several descriptions of bricks made for the
London market, and their relative prices, as given in
the Builders9 and Contractors' Price Book, for 1868 are
as under, viz.:—
Price per 1,000.
£ s. d.

Malm cutters
„ seconds
.
.
.
.
„ paviours
„ pickings .
.
.
.
.
„ stocks
„ roughs
.
.
.
.
.
„ place
Common stocks
„ roughs
„
place
Red stocks
„ rubbers
Paving bricks
Dutch clinkers
The prices of the various kinds of fire-bricks will

5 5 0
3 12 0
3 2 0
.
3 2 0
2 7 0
.
1 18 0
1 10 0
2 2 0
1 16 0
1 8 0
2 5 0
3 4 0
2 10 0
2 5 0
be found at page 18.
.

The bricks commonly sold are known by the following terms:—
Cutters.—-These are the softest, and are used for
gauged arches and other rubbed work.
Malms.—These are the best building bricks, and am
only used in the best descriptions of brickwork; colour
yellow.

156

RUDIMENTS OF THE

Seconds.—These are sorted from the best qualities,
and are much used for the fronts of buildings of a
superior class.
Paviours.—These are excellent building bricks, being
sound, hard, well shaped, and of good colour. They
must not be confounded with paving bricks, having
nothing in common with them but their name.
Pickings.—These are good bricks, but soft, and
inferior to the best paviours.
Rough Paviours.—These are the roughest pickings
from the paviours.
Washed Stocks.—These are the bricks commonly used
for ordinary brickwork, and are the worst description of
malms.
Grey Stocks.—These are good bricks, but of irregular
colour, and are not suited for face work.
Rough Stocks.—These are, as their name implies, very
rough as regards shape and colour, and not suited for
good work, although hard and sound.
Grizzles.—These are somewhat tender, and only fit
for inside work.
Place Bricks.—These are only fit for common purposes,
and should not be used for permanent erections.
Shuffs.—These are unsound and shuffy—that is, full
of shakes.
Burrs.or Clinkers. —These are only used for making
artificial rockwork for cascades or gardens, &c.
. Bats.—These are merely refuse.
It may be here observed, that at the brickworks
round London the bricks made are usually in the form
of regular paralleIopipe,dons, 9 in. long, 4 | in. wide, and
3 in. thick. If in the execution of apiece of brickwork,
bricks,of other shapes are required, it was formerly the
practice, and still sometimes is, for the bricklayer to cut

ART OF MAKING BRICKS AND TILES.

157

the ordinary bricks to the required shape. This practice,
so destructive to sound bond and good work, cannot be
too strongly reprehended; * especially now that the
manufacture is free from the trammels of the excise
there can be no excuse for not making bricks of a great
variety of shapes for various purposes.
40. Brickmaking at Cheshunt.—-In the " Illustrations
of Arts and Manufactures/' by Mr. Arthur Aikin, is a
valuable paper on pottery and brickmaking, the perusal
of which is strongly recommended to the reader. The
following notice is there given of the Cheshunt bricks:—
" At Cheshunt, in Hertfordshire, is a bed of malm earth
of the finest quality, no less than 25 ft. in depth; from
this are made the best small kiln-burnt bricks, called
paviers." Not having an opportunity of personally
examining the Cheshunt works, the author requested
Mr. B. P . Stockman to do so, and, in reply, received
the following communication, from which it appears that
kiln burning has been now disused for some time at
Cheshunt; clamping being now generally adopted :—
" There are no bricks now made near London of
natural malm; the once well-known bed at Grays in
Essex has been exhausted some years. No one can
inform me of any bed of natural malm except that at
Cheshunt, and I was told, previous to my going there,
that I should not find the works conducted as I had
been led to expect from your letter.
" There are only two brickmakers at Cheshunt, and,
from going over their works, I am able to vouch for
the accuracy of the following particulars.
* The brick columns, whose failure caused the frightful accident which
occurred in January, A.D. 1848, during the erection of the new buildings
at the Euston Station of the North Western Railway, were built in this
way. The additional cost of bricks made expressly for the work, of such
forms as would have bonded properly together without any cutting, would
have been very trifling.

158

RUDIMENTS OF THE

" There is a bed of natural malm, and a bed close to
it of ordinary brick-earth, which also contains malm.
When they make malms, which they were not doing at
the time of my visit, they do not use the natural malm
earth by itself, but wash and mix chalk with it, and I
am told that they never have made malms without
adding chalk to the natural earth, although the proportion is small compared to that required for the other
bed from which they also make malms. The earth is
soiled with ashes precisely in the same way as in the
London works, and turned over and puggepl in the
same kind of pug-mill. The bricks are hacked and
clamped, as in London, and there are none burnt in
kilns, nor have been for many years. There are no
kilns on the ground, and no kiln burning of any
description, though in former years there used to be
kilns for bricks and tiles, and also for glazed ware.
" The bricks made at Cheshunt are very superior to
the London bricks; in fact, the stock made there is
really a kind of malm brick, and the malms themselves,
as you may suppose, are perfection. I examined the
brick-earth from both pits, and saw the several processes
of moulding, hacking, scintling, and clamping going
on. The names of the different qualities are the same
as in London; but, as regards quality, some of the
common descriptions are equal to the London malms,
and I believe the shuffs would be sold for malms in
London."
41. Brickmaking is carried on to a great extent all
round the metropolis, but the principal brick-fields are
situated north of the Thames.

ART OF MAKING BRICKS AND TILES.

159

I I I . COST OF MANUFACTURE.*

42. We propose to consider the cost of manufacturer
under three heads, viz.:—
1. Materials and fuel.
2. Machinery and tools*
3. Labour.
I. MATERIALS AND FUEL.

43. Clay.—The cost of brick-earth must depend very
much on the circumstances of the locality, but it is
usually considered to be worth 2s. 6d. per 1,000 bricks,
exclusive of getting.
44. Chalk.—The cost of chalk is trifling where the
works have the advantage of water carriage, as it can
be brought to the canal wharfs round London at 2s. lOd.
per ton. To this must be added the cartage, which, in
some cases, must be a serious expense.
45. Sand.—The above remarks apply to the moulding sand; which is brought from the bed of the Thames,
near Woolwich, in barges to the canal wharfs at 2s.
per ton, a ton being about 1J cubic yard. To this must
be added cartage, and labour in drying the sand to
make it fit for use.
I t is difficult to say what quantity of sand is used per
1,000 bricks, but the cost may be taken approximately
at from 6d. to Sd. per 1,000 bricks.
46. Breeze.—The quantity of breeze required varies
according to circumstances; the proportion may be
taken to range from 12 to 20 chaldrons per 100,000
bricks. The cost of breeze may be taken at about 105.
* T*he estimates under this head must be considered as belonging to
the date of the first edition of tins work (1850), but later prices will be
found at page 162.

160

RUDIMENTS OP THE

per chaldron. I t may here be mentioned, that in
London stringent regulations are in force to prevent
householders from making use of their domestic ashes,
which are collected by parties who contract with the
parish authorities for this privilege.
In the Midland Counties the domestic ashes are
generally used for manure, the ashes being thrown into
the cesspools, an arrangement which would not be permitted in the metropolis. This mode of disposing of
the domestic ashes completely prevents the use of breeze
in the manufacture of bricks in the district where it is
practised.
47. Soil.—The cost of soiling cannot be very accurately ascertained. The quantity of soil required depends much on the quality of the brick-earth; 35
chaldrons per 100,000 bricks may be considered a fair
average. The cost per chaldron may be taken at 8s. to
9s. To this must be added the cost of harrowing to the
clay heap, say 10s. to 12s. per 100,000 bricks.
48. Coals and Wood.—The quantity of faggots required will depend on the number of live holes. This
item of expense is very trifling, say 10s. per 100,000 for
faggots and coals to light the clamp.
49. Water.—The water required for the washingmills is pumped into the troughs as before described,
and as shown in the drawings of the washing-mills,
fig. 7. That which is used in tempering the clay is
brought in buckets from the nearest pond on the works.
In some yards the supply is drawn from wells by the
contrivance known in the East as a shadoof, and in use
at the present day in Germany, and throughout Russia.
This simple contrivance is described at page 3 of Mr.
Glynn's "Rudimentary Treatise on the Construction
of Cranes and Machinery," and the reader is there-

ART OF MAKING BRICKS AND TILES.

161

fore referred to the description and wood-cut there
given.
It may, however, be worth while to remark> that there
is scarcely any difference between the ancient shadoof
used in Egypt in the time of' the Israelitish bondage
and that in common use at Stoke Newington, and other,
places near London, in our own time.
It is impossible to make any calculation as to the
proportionate cost of the necessary supply of water
to a brickfield, as it forms a portion of the cost of
tempering, and cannot be separated from it.
I I . MACHINERY AND TOOLS.

50. The average cost of the machinery and tools required in a London brickfield is about as follows:—
Chalk and clay mills, together . . .
Pug-mill .
. . .
. \
Cuekhold
For each moulder are required—
1 moulding stool, complete, at
1 mould
„
3 sets of pallets, 26 in each set
3 bearing-off barrows . . .

.

£
£60 to 70
.
10
5*,to 0

.
.
.

.
.
.

.

.

s.
0
0
6

d.
0
0
0

0 14
0 10
at 35. 0 9
at 12s. 1 16

0
6
0
0

In addition to the above are required, a few planks,
shovels, barrows, buckets, sieves, and other articles, the
aggregate cost of which it is impossible to estimate.
No buildings are required for the actual manufacture.
I t is, however, usual for the foreman, or " moulder/'
to live at the field. Stabling may be required or not,
according to circumstances and locality.

162

RUDIMENTS OF THE
I I I . LABOUR.

51. The cost of labour, &c., may be taken as follows:—
Per 1,000 bricks.
£ s. d.
Rent of
field
0 0 3
Ashes
0 4 6
Removing top mould
0 0 2
Digging earth
0 0 6
Soiling and turning earth
0 0 6
Chalk and expense of washing
.
.
.
. 0 0 3
Moulding
0 4 4
Horse grinding earth
0 0 6
Sand
. . . 0 0 6
Straw and hurdles
0 0 4
Setting
0 1 8
Bolting, sorting, &c
0 0 6
Loading
.
.
.
. .
.
.
. 0 0 6
Implements, &c
0 0 6
Superintendence
0 0 9
Interest on capital
0 0 9
Royalty
0 2 0
Bad debts
0 1 0
Preparing hacks, obtaining water, making roads,
coals and wood in burning, materials for
building sand-houses «
•
.
.
. 0 0 6
1 0 0

This is the actual cost for every thousand bricks before they leave the field; and in order to secure a fair
profit, i. e.y about 20 per cent., the stock bricks must be
sold at £ 1 8s. per 1,000; while the place bricks will
sell at from 15s. to £ 1 , the grizzles and rough bricks
at from 19s. to £l 3s., and the shuffs at from 8$. to
10s. per 1,000.

BRICKMAKING AT THE COPENHAGEN TUNNEL, ON THE
GREAT NORTHERN RAILWAY.

After the above description of the ordinary practice
of London brickmakers was written, Messrs. Pearce
and Smith, the contractors for the Copenhagen Tunnel,

ART OF MAKING BRICKS AND TILES.

168

on the line of the Great Northern Railway, commenced
brickmaking on a large scale at the tunnel-works; and
as the mode of manufacture practised by them was new
at the time in London, a short notice of it may be
interesting:—
The clay is neither weathered nor tempered, but as
soon as dug is wheeled up an incline to the grindingmill,- which consists of a single pair of cast-iron rollers,
driven by a steam-engine. The clay is mixed with a
certain proportion of sifted ashes, and, passing between
the rollers, falls into a shed, whence it is, without further
preparation, wheeled to the moulders.
The moulds are of wood, and the process employed is
that known as slop-moulding.
The moulding and drying processes are both carried
on in drying houses, with flues under the floors.
The bricks, as soon as moulded, are carried one by
one to the floors, where they remain until dry, when,
without being hacked, they are wheeled to the kilns.
The kilns are of the construction commonly used in
the Midland Counties, but have no sheds at the sides to
shelter the fires. The fuel used is coal.
The bricks thus made are of an irregular reddish
brown colour, and of fair average quality.
On first commencing operations, Messrs. Pearee and
Smith made a large quantity of bricks without any
admixture of ashes, sand only being added to diminish
the contraction of the clay. These bricks burnt of a
clear red colour, and were mostly very hard, but proved
brittle, and were apt to become cracked in burning.
Amongst other novelties adopted, may be mentioned
the use of saw-dust in lieu of sand,* the latter material
* It may be necessary, perhaps, to remind the reader that sand is used
for many purposes besides that of sanding the brick-mould.

164

RUDIMENTS OF THE

being very costly, whilst the former is supplied on the
works from a saw-mill worked by a steam-engine, which
at the same time drives the mortar-mill, and works the
lifts at two of the tunnel shafts.

REFERENCE TO ILLUSTRATIONS ACCOMPANYING THE FOREGOING ACCOUNT OF BRICKMAKING IN THE VICINITY OF
LONDON,

52.—Pig. 1. General Plan of a Brickwork.
(Scale 40 ft. to an inch.)
A.
B.
c.
D.
E.
p.
G.
H.
K.K.

The chalk-mill.
The clay washing-mill.
The pump.
The shoot to the brick-earth.
The brick-earth turned over in readiness to receive the malm.
The pug-mill.
The moulding stool.
The hack ground.
Clamps.

53. The Chalk-mill.
Figs. 2 and 3. Section and Plan. (Scale 10 ft. to an inch.)
a.a. Grinding-wheels.
b. Inlet from pump.
c. Outlet to clay washing-mill.
Details. (Scale 5 ft. to an inch.)
Fig. 4. Grinding-wheel.
Fig. 5. Mode of connecting the axle-tree of the grinding-wheels with
the centre shaft.

The mill consists of a circular trough lined with brickwork, and furnished with a pair of heavy wheels with
spiked tires, which, being drawn round by horses, crush
and grind the chalk until it is reduced to a pulp. The
wheels are shown in detail in fig. 4. It is necessary
that they should accommodate themselves to the level
of the chalk in the trough, and to effect this, the framing

ART OF MAKING BRICKS AND TILES.

165

of which the axle-tree forms a part is secured to the
centre shaft by a staple, as shown in fig. 5, which
allows the whole of the timbering to rise or fall, as may
be requisite. The centre shaft is a bar of iron, steadied
by being built up in a mass of brickwork. The yoke
beams are kept at the proper height, and their weight
supported by common light chaise wheels, about 2 ft. 6 in.
diameter, which run on the outside of the horse track.
The mill represented in these engravings is mounted for
two horses; many mills, however, have but one.
54. The Clay-washing Mill.
Figs. 6 and
a.
b.
ex.
d.d.
e.

7. Plan and elevation. (Scale 10 ft. to an inch.)
The inlet from the chalk-mill.
The outlet to the shoot.
The harrows.
The cutters.
The pump.
Details. (Scale l j in. to 5 ft.)
Fig. 8. The cutters.
Fig. 9. The outlet to the shoot, and the strainer.
Fig. 10. The strainer.

The mill consists of a circular trough of larger dimensions than that of the chalk-mill, also lined with brickwork, and furnished with a two-horse gin, to which are
attached knives and harrows, which, in their passage
round the trough, cut up the clay and incorporate it
with the pulp from the chalk-mill. The framing of the
gin is very simple, and requires no description. The
knives, or cutters, are placed in two sets, four in each.
They are fixed in an upright position, and steadied to
their work by chains, and by being bolted together with
bolts passing through tubular distance pieces, as shown
in fig. 8. The knives cut the clay and clear the way
for the harrows, which are similar to those ujsed for
agricultural purposes, and are merely suspended by

166

RUDIMENTS OF THE

chains from the timber framing. The pump is worked
by the horizontal wheel F, fig. 7, which is provided
with friction rollers on its rim, for the purpose of lifting
the lever G, which raises the lever of the pump by means
of the spindle H. The outlet to the shoots is simply a
square trunk made of 2 in. plank. It is furnished with
a brass grating, or strainer, shown in fig. 10. The bars
are f in. wide, and J in. apart, so that even small stones
will not pass through. This grating is fixed in grooves,
so that it can be lifted out of its place by the handles,
when required.
55. The Pug-mill.
Fig. 11. Elevation. (Scale 4 ft. to an inch.)
a. The yoke arm.
b. The opening for the ejectment of the earth when ground.
c. The brick-earth surrounding the mill, on which is an
inclined barrow road to the top of the mill.
Fig. 12. Section. (Scale 2 ft. to an inch.)
a.a. Force knives. These are not provided with cross knives,
their purpose being merely to force the ehrth downwards
and out at the ejectment hole.

56.—Fig. 13. Isometrical View of the Moulding StooL
(Scale 4 ft. to an inch.)
a.
b.
c.
d.
e.
/.

The lump of ground earth from the pug-mill.
The moulder's sand.
The clot-moulder's sand.
The bottom of the mould, termed the stock-board.
The water-tub.
The page) which is formed of two rods of f ths of an inch round
or square iron, nailed down at each end to the wooden
rails or sleepers on which they rest. The use of the page
is to slide the new bricks, with their pallets, away from the
moulder with facility.
g. The pallets in their proper position for use.
h. A newly-made brick just slidden from the moulder, and ready
for the taking-ofF boy.
L The moulder's place.
m. The clot-moulder's place.
n. The taking-ofF boy's place.
o. The cuckhold, a concave shovel used for cutting off the ground*
earth as it is ejected from the pug-mill.

ART OF MAKING BRICKS AND TILES.

167

75.—Eig. 14. Isometrical View of the Brick Mould,
with its detached bottom or Stock-board. (Scale 2 in.
to a foot.)
a.a.a. The iron pegs on which the mould rests during the operation of moulding. They are driven into the stool in the
positions shown in the drawing ; their height from the stool
regulates the thickness of the brick. The mould is lined
throughout with sheet-iron, which is turned over the edges
of the mould at the top and bottom.

58.—-Fig. 15. The Hack Barrow—-loaded.
to an inch.)

(Scale 2 ft.

Pig. 16. The hack barrow—unloaded. (Scale 2 ft. to an inch.)

59. The Clamp.
Fig. 17. Transverse section (parallel to necks). (Scale 10 ft. to an
inch.)
Fig. 18. Longitudinal ditto
ditto
ditto.
a. The upright.
b.b. Close bolts.
c. Live hole.
d. Bestowing.
Details. (Scale 2 ft. to an inch.)
Fig. 19, Plan of the lower course of scintles.
Fig. 20. Plan of the upper course of scintles.
, The live hole.
It should be understood that the directions of the scintles,
as well as that of the paving below it, are changed for every
neck, so as to correspond with the upper work, as shown in
the figures.
Fig. 21. Detail of the end of the upright, showing the paving, the
scintling, the live hole, and the 7 in., 4 in., and 2 in. courses of breeze.

CHAPTER VI.
LONDON

TILEKIES.

1. The general term, " Tile Manufacture," is so comprehensive, that it would be impossible, "within the limits
of a little volume like the present, to give anything like
a complete account of the manufacture of the different

168

RUDIMENTS OF THE

articles made at a large tilery; we only propose, there*
fore, in the present chapter, to give a succinct account
of the manufacture of pantiles, as carried on at the
London tileries, which will serve to give the reader a
general idea of the nature of the processes employed in
tile-making. It must, however, be borne in mind, that
although the principle of proceeding is the same in each
case, there are no two articles made exactly in the same
way, the moulding and subsequent processes being
carried on in a different manner, and with different
tools and implements, for every description of article.
The manufacture of plain tiles and drain tiles has
already been described in Chap. IV., to which the
reader is referred, as also to the supplementary chapter
at page 220.
2. The following is a list of the principal articles
made at the London tileries:—
Oven tiles.
10-in. paving 1
tiles.
Foot
ditto
Plain tiles.
Pantiles.
Ridge tiles.
Hip tiles.
Drain tiles.

Kiln bricks.
Fire bricks.
Paving bricks.
Circulars (for setting coppers,&c.)
Column bricks (for forming columns).
Chimney-pots.
Garden-pots.
Drain pipes.
And anything r equired to order.

For all these articles (excepting fire bricks) the same
clay is employed (mixed, for the making of paving tiles,
oven tiles,* kiln bricks, paving bricks, circular bricks,
and column bricks, with a certain quantity of loam),
and they are all burnt in the same kiln, the fire bricks
included; but each different article presents some peculiarity in the processes intervening between the tempering and the burning, having its separate moulding*
* Por oven tiles the stuff must be of superior quality.

ART OF MAKING BRTCKS AND TILES.

169

Fig. 1.

stool, frames, strike, &c, and being stacked and dried
differently. The details of these differences, however
(even would our limits allow us to describe them), would
scarcely be suited to the pages of a rudimentary work
intended for popular reading.
i

170

RUDIMENTS OF THE

Figs'. 2 and 3.

= r
&
BUILDINGS AND PLANT,

3. Pug-mill—The pug-mill used in tile making for
pugging, or, as it is termed, grinding the clay, differs
considerably from that used in briek-making. The tub,
instead of being conical, is made to taper at both ends.,

ART OF MAKING BRICKS AND TILES.

171

Fig. 5.

ts

rrf
"FT

and the ejectment hole is at the bottom instead of in
the front, as in the brick pug-mill.
The knives, also, are made in a superior manner.
I 2

172

RUDIMENTS OF THE

The mill is provided with force knives without cross
knives at top and bottom. See figures 1, 2, and 3.
The pug-mill is placed under cover in a shed called
the grinding shed.

ART OF MAKING BRICKS AND TILES.

173

Fig. 6.

4. The Sling, fig. 4, is simply a piece of thin wire
with two handles, used for cutting the clay.
5. Moulding Shed.—Tiles are made^nder cover in
she,ds about 7 yards wide, the length of the shed depending on the number of moulding tables, the area
allotted to each table being about 7 yards in length by
4 yards in breadth.
The moulding tables are placed against one side of

174

RUDIMENTS OF T H E

Fig. 10.

the shed, and the remainder of the area is occupied by
the blocks or drying-shelves; every shelf being formed
with three 1 in. planks placed edge to edge, and separated from each other by bricks placed edgewise at the
end of the planks, as well as at intermediate points,
each block containing about 14 shelves, and thus
measuring 12 ft. long by 2 ft. 8 in. wide, and about 7 ft.
high. A passage way, 3 ft. wide, is left round the
blocks, to give free access to every part of them.
These details will be understood by reference to fig. 5.
6. The Pantile Table, or moulding table, is shown in

ART OF MAKING BRICKS AND T I L E S .

Fig. 11.

Fig. 12.

Fig. 16.

Fig. 15.
3FT

fig. 6. I t is furnished with a trug or trough, in which
the moulder dips his hands when moulding, and with
a block and stock-board, on which the tile mould is
placed in the operation of moulding.
7. The Block and Stock-board is shown in fig. 7,
The two form one piece, which rests on the moulding
table, and is firmly keyed to it by means of a tenon on

176

RUDIMENTS OF T H E

Fig. 13.

the under side of the block passing through a mortice in
the table. Four pegs, driven into the table at the corners
of the block and stock-board, serve as a support for the
mould and regulate the thickness of the tile, f in. being
the thickness of a pantile.

177

ART OF MAKING BRICKS AND T I L E S ,

?.14.

=§FT

8. The Tile Mould is shown in fig. 8, and requires no
particular description.
9. The Boll, fig. 9, is merely a round roller of a
particular size, as shown by the scale, and is used for
striking a smooth surface to the tile.
10. The Washing-off Table, fig. 10, is a stand with
i 3

178

R U D I M E N T S 0!F THIT

Figs. 17 and 18.

10

20

30

40

5 OFT

a water trough and a frame called the Washing-off
Frame, see fig. 11, on which, when moulded, the tile is

ART OF MAKING BRICKS AND TILES.

179

Fig. 19.

10

20

50 _

washed into a curved form. The washing-off table is
placed at the left hand end of the pantile table, and
near the block.

180

RUDIMENTS OF T H E

Fig. 20.

10
,11,1,11,1,-

20
1

SO
.

-|

40
,

50 ,.
n

fT

11. The Splay er, fig. 12, is an instrument on which
the tile is removed from the washing-off frame to the
block.
12. The Thwacking Frame, fig. 13, is a frame on

ART OF MAKING BRICKS AND TILES.

Fig. 21.

181

182

RUDIMENTS OF THE

Fig. 22.

ART OF MAKING BRICKS AND T I L E S .

183

which the tile, when half dry, is thwacked or beaten
with a thwacker (fig. 15), to correct any warping which
may have taken place whilst drying in the block.
When thwacking those tiles taken from the bottom
of the block, the thwacking frame is placed upon the
Thwacking Stool, fig. 1 3 ; but when the tiles to be
thwacked are at the top of the block, the thwacking
frame is placed upon the Thwacking Horse, fig. 14,
which brings it conveniently to their level.
The Thvjacking Knife, fig. 16, is used for trimming
the wing of the pantile immediately after thwacking.
13. The Tile Kiln, figs. 17, 18, 19, 20, 21, and 22,
consists of a kiln with arched furnaces, enclosed in a
conical building called a dome. The arrangement of
the whole building will be clearly understood by reference to the figures, and to the detailed description at
the end of this chapter.
PROCESS OF MANUFACTURE.

14. Clay-getting and Weathering.—The clay used for
making tiles is purer and stronger than that used for
making bricks, and consequently requires more care in
its treatment.
When the clay is too strong, it is mixed with sand
before passing it through the pug-mill, but this is not
often required.
The weathering of the clay is performed by spreading
it out in thin layers, about 2 in. thick, during the winter,
and each layer is allowed to receive the benefit of at
least one night's frost before the succeeding layer is
placed over it. Sometimes the clay is spread out in
the summer to be scorched by the sun, which effects
the weathering equally well. The greater the heat, or

184

BUDIMENTS OF THE

the sharper the frost, the thicker may be the layers, but
4 in. is the maximum thickness.
The object of the process of weathering is, to open
the pores of the clay, and to separate the particles, that
it may absorb water more readily in the subsequent
process of mellowing.
The clay thus weathered is thrown into pits, where it
is covered with water, and left for a considerable time'
to mellow, or ripen.
15. Tempering.—The process of tempering is performed simply by passing the clay through the pug-mill.
If the clay be very foul, that is, full of stones, it is slung
before using, and passed a second time through the mill.
For chimney-pots and similar articles, the clay is slung
either once or twice, and pugged, or, as it is called,
ground, twice or thrice, according to the nature of the
clay, and the purpose to which it is to be applied.
16. Slinging.—The operation of slinging is as follows : as the clay issues from the ejectment hole of the
pug-mill, it is cut into lengths of about 2 ft., with a
sling. These lumps are taken by the slingers and cut
up into slices, not exceeding | in. in thickness, during
which operation most of the stones fall out, and those
which remain are picked out by hand. The clay thus
freed from stones is once more ground, and is then
ready for the moulder.
(N.B. In some parts of England the clay is freed
from stones by sifting, and the tempering is performed
by treading; this part of the work being done by boys,
who tread in a spiral track, so as to subject each portion
of the mass to a uniform amount of kneading.)
17. Moulding.—The clay, as it issues from the mill,
is cut into lumps, called pieces, which are stacked on a
rough bench in the grinding shed. A labourer cuts

ART OF MAKING BRICKS AND TILES.

185

these lumps in half, each half being called a half-piece,
and wheels these half-pieces one by one to the pantile
table.
A rough-moulder, generally a boy, takes the halfpiece and squares it up, that is, beats it up into a slab
near the shape of the mould, and about 4 in. thick, from
which he cuts off a thin slice, the size of a tile, and
passes it to the moulder.
The moulder, having sanded his stock-board, and
placed his mould on the four pegs which regulate the
thickness of the tile, takes the slice of clay from the
rough-moulder, and puts it into the mould. He then,
with very wet hands, smooths the surface, cutting off
the superfluous clay with his hands, in long pieces, called
strippings, which are thrown to a corner of the table.
This done, he strikes the surface level with the roll; and
turning the tile out of the mould on the washing-off
frame, with very wet hands washes it into a curved
shape. He then strikes it smartly with the splayer, and
turns it over on that implement, on which he conveys it
to the block, where he deposits the tile with the convex
side uppermost, and, the splayer being withdrawn, the
tile is left to dry. The button end of the tile is placed
inside the block.
18. Thwacking.—The tiles remain in the block until
they are half dry, when they are taken out one by one,
placed on the thwacking frame, and beaten with the
thwacker to perfect their shape.
The wing of each tile is then trimmed with the
thwacking knife, and the tiles replaced in the block, still
with the convex side uppermost; but this time the button
end is placed outside. The tiles then remain in the
block until ready for kilning.
It should be observed that the tiles flatten slightly

186

RUDIMENTS OF T H E

whilst in the block, and for this reason the washing-off
frame is made a little more convex than the thwacking
frame, which corresponds to the permanent form of the
tile.
19. Kilning.—In setting the kiln, a course of vitrified
bricks is laid at the bottom, herring-bone fashion, the
bricks being placed 1\ in. apart. On this foundation
the tiles are stacked as closely as they will lie, in an
upright position, one course above another. As the
body of the kiln is filled, the hatchways are bricked up
with old bricks, and when the kiln is topped, they are
plastered over with loam or clay. The top is then
covered with one course of unburnt tiles, placed flat, and
lastly, upon these a course of old pantiles is loosely
laid.
The fires are lighted on Monday morning, and are
not put out until Saturday evening, whatever the articles
in the kiln.
The fuel used is coal, and the quantity consumed at
each burning about eight tons. This, however, varies
with the kind of articles to be burnt,—hollow goods, as
chimney-pots, garden-pots, &c, requiring less than more
solid articles. Foot tiles, oven ditto, and 10-in. ditto,
are stacked in the kiln the same way as paving bricks.
The covering on the top of the kiln varies in thickness,
according to the sort of goods to be fired.
COST OF MANUFACTURE.*

20. From the manufacture of tiles being carried on
under cover, the establishment of a large ti]e-work
involves a considerable amount of capital. The kiln
* The estimates here given refer to the First Edition, except where
otherwise stated.

ART OF MAKING BRICKS AND TILES.

187

used in London is very costly, such a one as we have
shown in figs. 17 to 22 costing in its erection no less
than £2,000.
The cost of making pantiles is about as follows,, per
1,000:—
£ s. d.
Clay—this is usually included in the rent, but, if purchased separately, may be taken at 2s. 6d. per yard
cube—2J yards cube make 1,000 pantiles .
Weathering clay
Mellowing ditto, and grinding once
.
Add for horsing the pug-mill
• *f .
•
•
If slung and ground a second time, add
. . . .
Moulding, including all labour in fetching clay from mill,
moulding, washing, blocking, thwacking, and blocking
second time
Setting and drawing kiln
Burning
Cost of making
.
.
.
Rent, repairs, breakage, contingencies, and profit .
Selling price per 1,000

.

.

0
0
0
0
0

5
5
2
1
2

7|
0
0
6
0

0 10 0
0 3 0
0 15 0

, 2 4 1|
• 1 5 lo|
. 3 10 0

21. The following are the ordinary prices, in 1862,
for a variety of articles, which will give an idea of the
comparative amount of labour bestowed upon them :-—
Plain tiles
. . .
Patent tiles
. . .
Pan, hip, or ridge tiles
Ornamental plain tiles
Paving tiles, 9 in.
.
10 „
.
»
12 „
•
Mathematical tiles, red .
„
white
Oven tiles

.
.
.
,
•

£
. per 1,000 2
3
»
»
3
*
a
3
9
»
»
12
»
.
14
99
3
99
3
each 0

s.
4
6
5
4
0
0
10
0
10
0

d.
0
0
0
0
0
0
0
0
0
9

22. The above sketch of the manufacture of pantiles
will give the reader a general idea of the processes used
in tile-making, but every article presents some peculiarity of manufacture. Plain tiles are dried on flats,
called Place Grounds. Hip and ridge tiles are washed

188

RUDIMENTS OF THE

and thwacked in a similar manner to pantiles. Drain
tiles are only washed. Paving tiles and oven tiles are
stricken with a flat strike instead of the roll, and are
not washed, but they are thwacked and dressed with a
knife.
23. Description of Illustrations.
Figs. 1, 2, and 3. The pug-mill.
The pug-mill used in tile-making is different from that used in brickmakin#, as will readily be seen from the figures.
Fig. 1. Elevation of pug-mill. (Scale J in. to the foot.)
Fig. 2. Details of the knives. (Seale | in. to the foot.)
These knives are made in a superior manner to those of the brick
pug-mills, both as regards strength and fitting. The mill is provided
with force knives at top and bottom, which have no cross knives
attached to them.
Fig. 3. Cross section of the tub. (Scale \ in. to the foot.)
a. The ejectment hole, which is at the bottom of the tub, and not
at the side, as in the brick pug-mill.
Fig. 4. The sling, or wire knife, used for cutting the clay into lengths
as-it issues from the pug-mill, and also for freeing the clay from stones
(slinging).
Fig. 5. The tile shed, shown in plan and section. (Scale 10 ft. to the
inch.)
a.a.a. The blocks, which consist of a series of shelves, on which the
tiles are placed to dry. Each shelf is formed of three 11-inch
planks. The shelves are 4£ in. apart, and are spaced off from each
other by bricks laid edgewise, at the end of the block, and also
midway between these points.
b.b.b. The moulding tables. ,
,
Fig. 6. The pantile table, used for moulding pantiles. (Scale f in. to
the foot.)
a. The half-piece squared up.
b. The block and stock-board.
c. The trug or trough.
d. The moulder's sand.
e. The strippings.
/ . A hole in the table for sweepings to drop through.
g.g.ff. The pegs on which the,mould is placed. There are four of
these pegs ; viz., one at each corner of the block and stock-board ;
and the distance to which they are driven below the top of the
stock-board, determines the thickness of the tile.'
Fig. 7. The block and stock-board. (Scale 1 in. to the foot.)
c. A tenon, which drops into a mortice in the table.
d. A mortice in c, by which the block and stock-board is keyed
tightly to the table.
Fig. ,8. The pantile mould. (Scale 1 in. to the foot.)
Fig. 9. The roll. (Scale 1 in. to the foot.)

ART OF MAKING BRICKS AND TILES.

189

Fig. 10. The washing-off table. (Scale \ in. to the foot.)
a. The washing-off trug.
h. The washing-off frame.
Fig. 11. The washing-off frame. (Scale 1 in. to the foot.)
Fig. 12. The splayer. (Scale 1 in. to the foot.)
Fig. 13. The thwacking frame placed on the thwacking stool. (Scale
1 in. to the foot.)
Fig. 14. The thwacking horse, on which the thwacking frame is placed
for thwacking; those tiles at the top of the blocks. (Scale ^ in. to the foot.)
a. The table on which the thwacking frame is placed.
b. The place where the thwacker stands to thwack.
ex. Two wheels to facilitate the moving of the horse from place to
place when required.
Fig'. 15. The thwacker. (Scale 1 in. to the foot.)
Fig. 16. The thwacking knife. (Scale 1 in. to the foot.) This is
simply an iron blade, with a piece cut out exactly to the intended profile
of the wing of the pantile, which is trimmed with it immediately after
thwacking.
Figs. 17 to 22. The tile kiln.
(N.B. The whole of the furnace and body of the kiln is constructed
of fire brick.)
Fig. 17. Plan of the kiln, taken through the body. (Scale 20 feet to
the inch.)
Lk. The hatchways.
Fig. 18. Plan of the basement, to the same scale, showing the entrance
to the vaults.
Fig. 19.* Section through the centre of the kiln, in the direction of
the line a b, fig. 18. (Same scale.)
Fig. 20. Section through the centre of the kiln, in the direction of the
line o d. (Same scale.)
Fig. 21. Transverse section of the furnaces. (Scale J in. to the foot.)
The section marked a is taken through the throat of the furnace, oh the
line marked % y, in fig. 22.
Fig. 22. Longitudinal section of the furnaces. (Same scale.) The
arrows in each of the above figures show the direction of the flues.

CHAPTER VII.
ON THE MANUFACTURE OF ENCAUSTIC TILES.

1. The highly-decorative pavements of the mediaeval
ages, principally to be found in our old ecclesiastical
structures, which often shared the fate of many beautiful
* This cut and the following are not quite accurate, the sides of the
dome not being straight, as shown in the engraving, but slightly convex.

190

RUDIMENTS OF THE

details of architectural ornament, by being made to give
way to what rustic churchwardens, and others of equal
taste and discernment, deemed improvements — after
attracting thefcattention of the antiquary for centuries,
have at length excited some interest amongst the practical minds of these our stirring business times. About
thirty years since a patent was obtained by Mr. S.
Wright, of the Staffordshire Potteries, for the revival of
this interesting branch of art, for such it may be truly
called. As might have been expected, many difficulties
beset the patentee,' and for some years nothing was produced equal to the old specimens. But still a beginning
was made that promised success when skill and capital,
and a determination to succeed, should be brought to
bear upon the subject. And these were not long wanting, as the patent ultimately passed into the hands of a
gentleman undeterred by difficulties or previous failures,
and who expressed his intention to make encaustic tiles,
such as would secure the public approbation, even if
each one cost him a guinea! This is the spirit that has
achieved such surprising results in our manufactures
generally, within a comparatively brief period; and no
wonder that in this, as in most other instances, success
has been the satisfactory result. We need scarcely say
that the gentleman referred to is Mr. Herbert Minton,
who, with untiring industry, collected the best specimens of old tiles that could be found in this country, and
by a succession of experiments overcame the obstacles
that had retarded the success of the undertaking.
2. The chief of these, obstacles was, to discover clays
of different colours that could be made to amalgamate
in such a way as to contract or shrink equally during the
processes of drying and firing; and until this was effected,
a perfect tile of several colours could not be produced,

ART OF MAKING BRICKS AND TILES.

191

sundry unsightly cracks appearing on the inlaid parts
of the surface. I t will be unnecessary to speak of the
present state of perfection to which these beautiful tiles
have been brought, further than to observe that they
are yearly becoming more appreciated, both on the score
of durability and ornament; and there can scarcely be a
doubt that, very soon, no ecclesiastical building, having
any pretensions to architectural superiority, will be considered to be complete in its decorations without them.
By way of information, we may add/ that not only
copies of old tiles are manufactured, but every variety
of design suitable for the character of the building they
are intended for are supplied. Indeed, almost any
pattern can be produced with facility; and we have seen
some of the arms of our nobility and gentry so finely
executed, that the uninitiated might be pardoned for
mistaking these inlaid clays for the highly-finished and
elaborate work of the pencil. In many instances they
have been adopted as a substitute for oil-cloth in the
halls and passages of the mansions of our nobility,
being considered far more beautiful, and, from their
durability, more economical also, in the long run.
3. We will now take a peep into the interior of Messrs.
Minton and Co/s manufactory.* We must first notice,
that the clays of which the tiles are composed are obtained in the immediate neighbourhood—the ordinary
marl producing a good buff colour when fired; another
kind a warm red; black is produced by staining with
manganese; blue with cobalt, &c. W'th the native
clays there is a slight admixture of Cornwall stone and
clay, and flint from Kent, &c. The whole are subjected
to a variety of washings and purifications—the clay in* Further details will be found in " Tomlinson's Cyclopaedia "—
article, Pottery and Porcelain.

192

RUDIMENTS OP T H E

tended for the surface, especially—-and passed through
fine lawn sieves in a liquid, or "slip" state, as it is
technically termed. I n this state it is conveyed to the
slip-kiln, or rather pumped on it, and boiled, until it is
in a plastic state, and fit for use.
4» After the modeller has done his part, the pattern
is cast in plaster in relief, and is then placed in .a metal
frame of the size required; but it should be stated that
to produce the ordinary 6-in. square tile, it is modelled
6§ in., to allow for shrinkage or contraction, which takes
place during drying and firing. The maker then commences his operations. A piece of the fine clay for the
surface is flattened out to about a quarter of an inch
thick, somewhat after the manner of preparing a pie
crust, and this is thrown upon, and pressed upon, the
plaster pattern, and receives, of course, a correct indentation, or outline of the design. The metal frame containing
the plaster mould is divided horizontally, and after the
surface is put in, the upper part of the frame is screwed
on, and the maker fills up with clay of a somewhat
coarser description, to form the tile of the requisite
thickness. The tile is then put under a screw-press to
impart the proper degree of solidity.
5. As far as we have gone, the tile is but of one
colour; next comes the task of giving the different
colours required. Suppose a tile be required of three
colours—red, blue, and buff. "We will say the surface
piece already put in is of abuff colour. The maker provides
himself with vessels of a suitable kind, containing—the
one the blue, the other the red colour, in a " slip" state,
and these he pours into those parts of the indented surface
that the drawing or finished tile before him tells him to
be correct. These slips cover the surface entirely, and
there is now not the slightest appearance of any pattern

ART OF MAKING BRICKS AND TILES.

193

or design, After remaining in this state for three days,
until the water has evaporated for the most part, the
process of scraping or planing the surface commences,
which is an operation requiring care, though easily
effected by experienced hands. The pattern then makes
its appearance, but the colours are scarcely distinguishable the one from the other.
6. The tile is then finished as far as the maker is
concerned; and, after remaining in the drying house
from 14 to 21 days, according to circumstances, is conveyed to the oven, where it is exposed to an intense
degree of heat for about 60 hours. After being drawn
from the oven, the tile is finished, except it be that the
parties ordering wish the surface glazed, a rapid and
easy process, the dipper merely placing the,surface in %
tub of glaze.
.,
• ' • ' ! ; • , * h^
7. Plain self-coloured tiles, such as black, red, chocolate, buff, &c, and als&j tesserge/ are made of the s|^me
material as the encaustic, only that it is dried longej in
the kiln, passed t h r o u g h p u t s to reduce it to a poyaer,
and is then finely sifted. "Presses of great poWer^made
under Prosser's patent, make these tilesv ^ TKepowdered
clay is swept into a recess of the proper size, the screw
descends, and, by its immense power, presses the powder
into a solid tile, ready for drying and firing. One man
can, with ease, make about 500 per day.
8. Tessera.—The tesserae made by Messrs. Minton,
under Mr. Prosser's patent, are now extensively used
for mosaic pavements, for which they are admirably
adapted. A few words will suffice to explain the nature
of the improvements effected in this branch of art by
the introduction of the new material.
The mosaic pavements made by the Romans were
formed of small pieces of stone or marble of various
K

194

RUDiMENTS OF THE

colours, bedded one by one in a layer of cement, each
of the pieces being levelled with the others as the work
proceeded, and on the completion of the work the unavoidable inequalities of surface were corrected by
rubbing the whole to a plane surface.
. This mode of proceeding was attended with many
defects. The irregular shapes of the tesserae caused
the cement joints to be of a thickness that greatly injured the effect of the design, whilst the piecemeal way
in which the work was laid rendered it very difficult to
produce a level surface.
It is not our purpose here to detail the several attempts that have been made during the last few years,
with various degrees of success, to produce mosaic pavements, by the use of clay tesserae, coloured cements,
&c.j but it will readily be understood that the principal
difficulties to be overcome in the use of solid tesserae
are those arising from irregularity in the shape and size
of the several pieces, as well as the great labour and
expense attending the laying of such pavements piece
hj piece.
These difficulties have been entirely overcome by the
use of the patent tesserae, which, being made in steel
dies, by the process above described, are perfectly uniform in size, and fit closely together, with an almost
imperceptible joint.
The mode in which the tesserae are used is precisely
the reverse of the Roman process, and is as follows:—
a coloured design of the intended mosaic having been
drawn to scale, after the fashion of a Berlin Mwool
pattern, the pattern is set out full size on a cement floor,
perfectly smooth and level, and on this floor the tesserae
are placed close together, the workmen being guided in
the arrangement of the colours by the small drawing.

ART OF MAKING BRICKS AND TILES.

195

The pieces are then joined together by a layer of
cement applied to the upper surface, and in this way they
are formed into slabs of convenient size, which, when
hard, are ready for use, and can be laid with as much
ease as ordinary flagstones. I t will at once be understood, that the side of the slabs which is next the floor
during the process of manufacture forms the upper
side of the finished pavement, the pattern appearing
reversed during its formation.

CHAPTER V I I I .
ON THE MANUFACTURE OF BRICKS AND DRAIN
PIPES BY MACHINERY.

I T is the general opinion that brickmaking by machinery is not economical in small work, since the cost
of moulding bears so small a proportion to the total
cost. In large engineering works, however, where a
contractor requires many millions of bricks in a limited
time, for the construction of a tunnel or viaduct, the use
of machinery may be desirable. In this chapter we do
not, of course, pretend to give descriptions of the various
patented and other machines connected with the manufacture of bricks and tiles. Our object, in a work of
this kind, being to deal with the principles of the art
rather than with a multiplicity of minute details. We
may, however, in order to show the great vitality of the
trade, quote a few titles of inventions, &c, belonging to
the years 1861 and 1862. The patent list displays the
strong tendency to invention for making bricks, &c, by
machinery. Thus, we have—
K 2

196

RUDIMENTS OF THE

Wimball's patent for making bricks, tiles, and drain
pipes.
Morrell and Charnley's apparatus for making bricks,
tiles, and other articles from plastic materials.
Green and Wright's machinery for the manufacture
of plain and ornamental bricks, slabs, tiles, and quarries.
Basford's patent for constructing brick walls, and
ornamenting the materials to be used for the same.
Effertz' machinery for making bricks,' tiles, &c.
Grimshaw's patent for compressing brick-earth and
other materials.
Morris and Radford's patent for the manufacture of
fire bricks, blocks, &c.
Poole's patent for making ornamental bricks, tiles, &c.
Newton's machine for making bricks.
Sharp and Balmer's apparatus for the manufacture
and drying of bricks.
Grimshaw's patent apparatus, used in drying, pulverising, and compressing clay.
Piatt and Richardson's apparatus for making bricks.
Foster's method of rendering bricks impervious to
damp.
Smith's patent apparatus for the manufacture of
bricks, tiles, &c.
The following description of Oates's brickmaking
machine is from Tomlmson's " Cyclopaedia of Useful
Arts, &c." It was described by Mr. J. E. Clift, of
Birmingham, at a meeting of the Institution of Mechanical Engineers, in November, 1859, and the description is printed in the " Proceedings" of that body, and
is illustrated by four engraved plates, from which Mr.
Tomlinson has compiled the illustrative figure. We do
not give this machine as the best, since there are many
other well-known machines of merit in use; but we

ART OF MAKING BRICKS AND TILES.

197

offer it as an example of the mechanical means adopted
in this class of inventions.
< The present briekmaking machines at work are
divided by Mr. Clift into two classes, viz., those that
operate on the clay in a moist and plastic state, and
those for which the material requires to be dried and
ground previous to being moulded. I n the former class,
the plastic column of clay, having been formed into a
continuous length by the operation of a screw, pugging
blades, or rollers, is divided into bricks by means of
wires moved across, either while the clay is at rest or
while in motion, by the wires being moved obliquely at
an angle to compensate for the speed at which the clay
travels. This wire-cutting requires the clay to be soft,
so that the bricks are but little harder than those made
by hand, and require a similar drying before being placed
in the kiln; and all this renders the expense of manufacture about the same as for hand-made bricks. In the
second class of machines, the bricks are compressed in
a dry state in the mould; but the processes for drying
the clay, and reducing it to a uniform powder, add to
the cost of manufacture.
Mr. Oates has got rid of both objections, viz., the
difficulty respecting the previous preparation of the clay,
and the subsequent drying of the bricks. In his machine
the clay is used of such a degree of dryness as to allow
of its being mixed up and macerated, and compressed
into bricks by a single continuous action, the clay being
formed into a continuous column and compressed into
the moulds by the action of a revolving vertical screw.
The clay requires,, in general, no previous preparation
beyond that given by the ordinary crushing rollers, and,
in some cases, may be put into the machine direct from
the pit, unless it contain stones, when it is passed through

198

RUDIMENTS OF THE

a pair of rollers. Figs. 2 and 3, when joined at the
parts indicated by the dotted lines, form a longitudinal
section of the machine, and fig. 1 is a plan of the screw.
Fig. 1.

•V

•

I
The cast-iron clay cylinder A is expanded at the upper
part to form a hopper, into which the clay is supplied,
and the lower cylindrical portion is about the same in

ART OF MAKING BRICKS AND TILES.

199

%. a

diameter as the length of the brick mould ¥, at the
bottom of the pressing chamber B. The vertical screw
C is placed in the axis of the cylinder, and carried by

200

RUDIMENTS OF T H E

two bearings in the upper frame D ; this screw is
parallel at the lower part, the blade nearly filling the
parallel portion of the clay cylinder, and is tapered
conically at the upper part to nearly double the diameter.
When the clay is thrown loosely into the hopper it is
divided and directed towards the centre by the curved
arm E revolving with the screw shaft, and drawn down
by the tapered portion of the screw into the parallel
part of the clay cylinder in sufficient quantity to keep
this part of the cylinder constantly charged* The clay
is then forced downwards by the parallel portion of the
screw into the pressing chamber B, and into the brick
mould F, which consists of a parallel block equal in
thickness to a brick, and sliding between fixed plates
above and below> and containing two moulds, F and G,
corresponding in length and breadth to the bricks to be
made. The mould-block F is made to slide with a reciprocating motion by means of the revolving cam H,
which acts upon two rollers in the frame I, connected
to the mould-block by a rod sliding through fixed eyes;
and the two brick moulds are thus placed alternately
under the opening of the pressing chamber B to receive
a charge of clay, the mould-block remaining stationary
in each position during one quarter of the revolution of
the cam H. When the brick mould F is withdrawn
from under the pressing chamber, the brick is discharged from the mould by the descent of the piston K,
which is of the same dimensions as the brick mould;
the piston is pressed down by the lever M, worked by
the cam N, when the brick mould stops at the end of
its stroke, and is drawn up again before the return
motion of the mould begins. A second piston L acts in
the same manner upon the second brick mould G> and
the discharged bricks are received upon endless bands

ART OF MAKING BRICKS AND TILES.

201

O, by which they are brought successively to the froni
of the machine, when they are removed by boys to the
barrows used for conveying them to the kilns to be burnt.
The solid block that divides the two brick moulds
F and G- is slightly wider than the discharge opening
at the bottom, of the pressing chamber B, having an
over-lap, so that the making of one brick is terminated
before that of the next begins, in order to ensure completeness in the moulding. During the instant wheithis plank is passing the opening at the bottom of the
pressing chamber, the discharge of the clay is stopped,
and it becomes necessary to provide some means eithei
of relieving the pressure during that period, or of stopping the motion of the pressing screw. Accordingly
the pressure is relieved by an ingenious contrivance,
forming in effect a safety-valve, which prevents the
pressure in the chamber from increasing when the brick
mould is shut off, and also serves to maintain a uniform
pressure during the formation of the brick, so as to ensure each mould being thoroughly and equally filled
with clay; this is effected by an escape-pipe P, similar
in form to the brick mould, but extending horizontally
from the side of the pressing chamber, and is open at
the outer extremity. The regular action of the screw
forces the clay into the escape-pipe, as far as its outer
extremity, forming a parallel bar of clay in the pipe*
The resistance caused by the friction of this bar ifc
sliding through the pipe is then the measure of the
amount of pressure in the machine; and this pressure
carimot be exceeded in the machine, for the instant that
the brick mould is full, the further supply of clay, fed
into <the pressing chamber by the continuous motion of
the screw, escapes, laterally, by pushing outwards the
column of clay in the escape-pipe. The uniform pres?_
K 3

202

RUDIMENTS OF THE

sure of every brick in the mould up to this fixed limit
is ensured by the escape-pipe not beginning to act until
that limit of pressure is reached. Its action is similar
to that of a safety-valve, and the amount of pressure
under which the bricks are made is directly regulated
by adjusting the length of the escape-pipe. The latter
discharges a continuous bar of solid clay, advancing by
intermittent steps of J to \ in. in length, each time
that the brick mould is shut off and changed. The
projecting piece of clay from the end of the escape-pipe
is broken off from time to time, and thrown back into
the hopper of the machine.
The upper side of the solid block separating the two
moulds F and G is faced with steel: and the upper
face of the brick is smoothed by being sheared off by
the edge of the opening in the pressing chamber; the
under face of the brick is smoothed by being planed by
a steel bar E, fixed along the edge of the under plate,
and having a groove in it for discharging the shaving
of clay taken off the brick.
The screw shaft is driven by bevil gear from the shaft
S, which is driven by a strap from the engine, the speed
being adjusted according to the quality of the clay or
the wear of the screw. The screw is driven at about
thirty revolutions per minute, when at full speed, or one
brick for each revolution of the screw. The machine
completes 12,000 bricks per day, or an average of
twenty per minute. The clay, as already stated, can
be taken direct from the pit, passed through crushing
rollers, and then fed straight into the moulding machine.
Indeed, the clay within a quarter of an hour after being
brought from the pit may be seen stacked in kilns, and
in a few days burnt ready for use. The amount ^of
power required for driving the machine, and th£ wear

ART OF MAKING BRICKS AND TILES.

203

of the screw, vary according to the material worked.
With a calcareous marl about twelve horse-power was
found sufficient. When the material is very siliceous
the cast-iron screws wear out quickly. Gun-metal has
been found much more durable than iron for the screw
and mould-block.
I n burning bricks that contain much alumina, and
consequently retain a good deal of moisture, it is found
advisable to stack the bricks in the kiln in lifts of from
fifteen to twenty courses each. As soon as the bottom
lift has been stacked, small fires are lighted to drive off
the steam from the bricks, which might otherwise soften
those stacked above; the middle lift is then stacked and
similarly dried, and then the top lift; after which the
full fires are lighted.
The crushing strength of these bricks made in the
machines at Oldbury is said to be double that of the
hand-made blue bricks of the neighbourhood, being an
average of 150 tons compared with 76 tons, or 8,024 lbs.
per square inch compared with 4,203 lbs. The transverse strength, with 7 in. length between the bearings,
was found to be, for hand-made bricks, 2,350 lbs.,
for machine-made bricks, 3,085 lbs., and for the same,
hard burnt, 4,320 lbs.
One of the advantages of this machine is, that clay
containing a good deal of stone, which could scarcely**
be worked for hand-made bricks, can be used. Th&i
brick-earth at Cobham is very unfavourable for brickmaking, it being so weak and friable that hand-made
bricks made from it were crushed by a moderate pressure; when made by the machine, however, serviceable
bricks were turned out. A material containing 84 per
cent, of silica has been made by this machine into
bricks. The bricks had not any hollow or frog in the

204

RUDIMENTS OP T H E

upper space for holding the mortar, but arrangements
were being made for producing it.
The extent to which bricks absorb water is important, since dry houses cannot be built with bricks
that are very absorbent. A brick of 9 lbs. weight will
absorb about I lb. of water, and it is stated that the
bricks made by this machine absorb less.
The cost of Oates's machine is from £150 to £200,
exclusive of the engine for driving it. The cost of brickmaking varies according to the price of coal in different
localities; but there is very little variation in the price
of the unburnt bricks made by the machine, the difference arising chiefly from the varying amount of royalty
charged on the clay in the pit, which varies from Is.
to 2s. 6d. per 1,000. A machine at Cobham, employed
by Messrs. Peto and Betts, produced 200,000 bricks in
a fortnight of eleven days, but the average number per
week, of five and a half days, was considered to be
80,000, or at the rate of twenty-four bricks per minute.
The contract for the bricks in and out of the kilns,
exclusive of the cost of the coals, was first taken at
55. 9d. per 1,000 bricks; which was afterwards raised
to 6s. 9d., owing to the distance of the clay from the
machine. To this had to be added 6d. per 1,000 royalty,
and the wages of the engine-driver at 6d. per 1,000,
raising the expenses to 7s. 9d. per 1,000 bricks. The
quantity of coals required for burning the bricks, and
for the engine driving, might safely be taken at -J- ton
per 1,000; and the price of coal at that place being 26s.
per ton, the total cost of making the bricks by the machine amounted to 20s. per 1,000, including the burning.
The following particulars respecting drain-pipe making machines,, and hollow bricks, are also from Mr.
Tomlinson's " Cyclopaedia."

ART OF MAKING BRICKS AND TILES.

205

The large and increasing demand for draining tiles
and pipes has led to great economy in their manufacture. Some are moulded flat3 and afterwards bent?
round a wooden core to the
proper shape: others are made at
once of a curved form by forcing
the clay through a dod or mould,
fig. 4, by mechanical pressure.
The action will be readily understood from fig. 5, which represents a section of a strong iron
cylinder, containing a quantity of
clay in the act of being pressed
down with enormous force by a
solid piston or plunger. The
clay, as it escapes through the
dod, is evidently moulded into
the form of the pipe (also shown
in section), which is cut off in
lengths, by means of a wire, and
these, after a preliminary drying,
-%• 5.
are ready for firing. By using dods of different sizes,
pipes of various magnitudes are formed.
Fig. 6 is an elevation of a drain-pipe making
machine, which we have copied from Mr. Green's works
at Lambeth. The cylinder contains a second cylinder,
capable of holding a given weight of clay, adapted to
the moulding of a certain number of pipes at one
charge. Thus, one boaetfull will furnish five 9-in. pipes,
six 6-in. pipes, seven 4-in. pipes, and so on. By the
action of the rack the piston forces the clay through
the dod or die upon a table, so balanced by weights
that the lengthening pipe is sufficient by its weight to
force down the table, and when a certain length of pipe

206

RUDIMENTS OF THE

is formed, the hoy stops the machine hy shifting the
strap which drives the rack-screw from the fast to the
loose pulley, and then cuts off the length of pipe with
Fig. 6.

a wire, removes the pipe so formed, raises up the tahle,
sets the machine in action, and receives a pipe upon the

ART OF MAKING BRICKS AND TILES.

207

table as before. When all the clay is thus forced out
of the cylinder, the action of the rack is reversed^
whereby the plunger is drawn up out of the cylinder*
The cylinder, which moves on a kind of hinge, is then
tilted on one side to receive its charge of clay, and being
restored to its vertical position, the action proceeds as
before. By an ingenious contrivance, the fork which
shifts the strap from the fast to the loose pulley, is
weighted in such a manner that, when the boy raises
his foot from a treadle, the strap is at once moved on
to the loose pulley, and vice versd, thus giving the
attendant a third hand, and diminishing the chances of
danger from the strap. Mr. Green has a machine
worked by a screw, in which the process is continuous.
These pipes are washed with glaze before the firing, as
will be explained hereafter.
By means of a tile machine, the hollow bricks.axe
formed, which are so much recommended by the " Society for Improving the Condition of the Labouring
Classes," and introduced by them in the construction
of dwelling-houses for the poor. The idea of tabular
bricks is not new, for such articles were used by the
Romans in large vaultings, where lightness of construe*
tion was required, and they are said to be in common
use in Tunis at the present time. The size of the bricks
is 12 in. long, and three courses rise 1 ft. in height.
Nine hollow bricks will do as much walling as sixteen of
the common sort, with only a slight increase in weight.
In passing through the tile machine, or in the process of
drying, the bricks can be splayed at the ends for gables.
or marked for closures, and broken off as required in
use, or they may be perforated for the purpose of ventilation. If nicked with a sharp-pointed hammer, they
will break off at any desired line; and the angles may

208

R U D I M E N T S OF THE

be taken off with a trowel as in the common brick;
The bricks for the quoins and jambs may be made solid
or perforated, and with perpendicular holes, either circular, square, or octagonal: those in the quoins may
be so arranged as to serve for ventilating shafts. The
hollow bricks, from their mode of manufacture, are
more compressed than common bricks, require less
drying, and are better burned with less fuel.
The following figures represent some of the forms of
hollow bricks in common use. a, fig. 7, is an external
brick, l l f in. long, which with the quoin brick e}
and the jamb brick 6, are sufficient for building 9-in.
walls, e is 10J in. long, with one splayed corner for
forming external angles, reveals, and jambs of doors
and windows, either square or splayed. The internal
jamb and chimney brick, bj is 8 | in. long; c is an
Fig, 7.

internal brick, adapted to any thickness of wall beyond
9 in.: d is for 5|-in. partitions, or internal walls, and
arch bricks, and is used for floor and roof arches of
7 to 10 ft. span. / is used for the same purpose, with

ART OF MAKING BUlCKS AND TILES.

209

a webb to give extra strength, and to adapt them for
using on edges in partitions, 3 | in. thick to rise in
6-in. courses.
Fig. 8 represents a specimen of hollow brick work
^ ^ ^
in 6-in. courses, with square
rebated joints for extra strength.
These bricks are adapted to the
lining of flint or concrete walls.
•[<• • •
Fig. 9 is a section illustrative
i eli J
of the construction adopted in
H. R. H. Prince Mbert's model
^
houses. The span of the arches
m
•III
Is \
is increased over the living
i E! m m i j
rooms to 10 ft. 4 in., with a
1 [m © j§§|
proportionate addition to their
lii m m i
rise. The external springers
-fZ~
are of cast-iron, connected by
%.8.
wrought-iron tie rods.
. It is stated that there is an advantage of 29 per cent,
in favour of the patent bonded hollow bricks over ordi-

nary bricks, in addition to a considerable diminution in
the cost of carriage or transport, and of 25 per cent, on
the mortar and the labour.

210

BUTOIENTS OF THE

CHAPTER IX.
ADDITIONAL REMARKS ON THE MANUFACTURE OF
BRICKS BY MACHINERY,

I T is proposed here to supplement the previous chapter,
written by Professor Tomlinson in 1863, by giving
full descriptions of some of the most remarkable, or
most used, of the very many brickmaking machines
now before the public. The trade in producing brick
machinery itself has come to be a very large one, in
which great intelligence, energy, and capital have been
invested, and from which have emanated an immense
number of inventions, chiefly the subjects of patents.
The results have naturally been much rivalry and competition, so that, perhaps, there is no one of the trains
of machinery for making brick, which has had a success
enough to make it worth notice, which has not been exposed to partial advocacy, and to equally interested and
frequently more unjust depreciation.
I t would be highly out of place that " an outline " such
as this volume can alone pretend to, within its limits,
should undertake to appraise the relative merits or
demerits of the various machines we are about to notice
—the rather, as we are unable to treat the whole subject in the exhaustive manner that alone would justify
such criticism. The following notices, therefore, must
be viewed as merely collecting before the reader, with
sufficient illustrations, a few of the more prominent
brick and tile machines, or those most in use in Great

ART OF MAKING BRICKS AND TILES.

211

Britain, sufficient to serve as an index to those specially
interested, whereby more complete information may be
obtained through the respective makers or otherwise.
As has been sufficiently shown in the preceding
parts of this volume, the natural clays from which
bricks are to be made, though they may occasionally be
found in a state capable of being at once made into
brick, must most usually be subjected, after having
been dug out, to more or less disintegration, grinding,
and mixing into perfect plasticity, before being em*
ployed. For these purposes, the screen sometimes
being used beforehand, the crushing rollers and
the pug-mill are employed. Other methods of producing perfect freedom from adventitious matter and
perfect plasticity are occasionally employed, when
special qualities of extra fine bricks are sought for,
but with those we need not trouble the reader here.
The above machines are employed in combination,
i.e., as parts of one compound machine, as produced by
some makers, separately as turned out by others. The
clay-mill, with crushing rollers working on edge in a
circular pan, is also in use. Brick machinery itself,
since the invention of Prosser, many years since, is
divisible into two great classes, wet and dry clay machines, i.e., machines which form the brick, by moderate
pressure in moulds, from already tempered and plastic
clay, and those which, under a far more severe compression, mould the bricks from clay perfectly comminuted, but either dry, or at most only very slightly
moistened. One of the most salient advantages of the
dry method is, that it produces a denser brick, and one
that shrinks less both in drying and in baking than
do those made wet; and that a certain amount, though
not a very great one, of the labour and cost of the

212

RUDIMENTS OF T H E

preliminary preparation of the clay is saved. The
disadvantages, or some of them, are, that unless the
clay in the dry or merely damp state be scrupulously
well prepared, and unless a degree of pressure be
employed which demands a good deal of power, the
brick may be deficient in tenacity and in uniform
solidity, or even in perfect fairness of face. On the
other hand, with certain clays, and pressures beyond a
given point, bricks are thus produced, which, though
dense and resistant, have so wporous a surface as
hardly to take bond with either cement or mortar.
Fig. 1 represents Whitehead's Improved Clay OrushMff.l.

ing and Grinding Roller Mill, consisting of two pairs of
large iron rollers, fitted in a massive cast-iron frame.
The dimensions of the top rollers (which revolve at equal
speed) are 2 ft. 6 in. long by 1 ft. 8 in. diameter. The
lower pair (running as two to one, for more thoroughly
incorporating the clay) are 2 ft, 6 in. long by 1 ft. 6 in.

ART OF MAKING BRICKS AND TILES.

213

diameter. The above mill is constructed for the purpose of reducing rough strong clays or hard marls not
disintegrate by water, into a state to be rendered plastic
by future operations in the pug-mill, of which two difFig. 2.

ferent examples are given in figs. 2 and 3 by the same
maker.
Fig. 2 is a large and powerful pug-mill. The cylinder
is one strong loam casting made perfectly true; it is
erected upon a massive iron basement, and provided
with two cast mouth-pieces for the discharge of the
pugged clay, one situate on each side at bottom. These
mouth-pieces may have sliding doors fitted, to increase
or diminish the area of the orifice, so as to cause the
clay to be more or less finely ground. This is valuable
in admitting the adaptation of the mill to the pressing
out of large and small pipes, &c.
This mill makes about three revolutions per minute,
worked by the power of one horse. The cylinder is 24 in.

214

RUDIMENTS OF T H E

diameter inside, and 54 in. high; the total height to top
of vertical shaft is 87 in.
Fig. 3 represents Whitehead's Perforated Pug-mill.
The advantage of this mill is, that during the operation of pugging the clay is forced out through the

perforations at the sides in the plastic state, leaving
behind the stones, which are carried, by means of the
internal arrangement of the knives on the vertical shaft,
through an aperture at the bottom; thus combining
the process of pugging and screening in one operation.
We entertain some doubts of the advantages of this
machine, however ingenious; for screening as a preliminary operation should, whenever practicable, never
be omitted.
Fig. 4 shows a very good form of nearly portable

ART OF MAKING BRICKS AND TILES.

215

clay-mill. Mills in this form may be used for grinding
wet or plastic clay, but are more suitable for indurated
dry clays, which are to be used with one or other of the
dry-clay brick machines. The pan, as is evident from
Fig, 4.

the figure, revolves, and the runners are carried round
by it, being free to move within a certain range vertically. The pan is provided with curved blades, so fixed
as to keep the stuff constantly beneath the runners.
We now come to the composite machines, in which
crushing rollers and horizontal pug-mill are combined,
as in fig. 5.
For very hard clays, such as fire-clays for fire-brick,
two or even more pairs of crushing rollers may be
needed above each other, those closest set being at bottom.

216

ART OF MAKING BRICKS AND TILES.

The rollers are driven at different speeds, so as to
produce a n ^ a s well as .a mere squeeze between the sur-

faces, and so better disintegrate the clay. The rollers
are usually made about 20 in. diameter, and about 3 ft.
long. They are fed by hand, through a hopper at
top.
Having thus described the machinery generally in
use for the preparation of the clay, whether plastic or
dry, we proceed to illustrate a few of the brickmaking
machines themselves, commencing with those for operating on moist or plastic clays.
Fig. 6 represents a large machine as constructed by
Whitehead, of Preston, in which the rough clay thrown
in between the rollers at top is ground, and then passes

218

RUDIMENTS OF THE

at once into the vertical pug-mill, and is thence expressed
in two continuous prisms of the size in section of a brick
Fig, 7.

on flat, and which are at intervals cut transversely
into bricks by the wires of the frames, seen in the front
of the drawing. These are moved by hand.
Fig, 8 represents another form of machine, in
which the clay, already tempered, is drawn in and continuously expressed by a pair of rollers, the prism
being cut asunder into bricks by the radial wires
forming the arms of the wheel 0, which is moved automatically.
An extremely simply-contrived and most efficient
French machine of this class was exhibited in 1862 in
the French department. I t was an invention of M.
Jardin, and manufactured by Cazenave & Co., Paris.
At work in the Exhibition, it made at the rate of
twelve thousand per day of ten hours, with only the
attendance of two men. The division of the prism of
clay was eifected by wires attached to a wheel moved by

ART OF MAKING BRICKS AND TILES.

219

the machine, but differently arranged from that of

fig. 8.

The following machine belongs to this same class.
It is Clayton and Co.'s second-sized horizontal brick
L2

ART OF MAKING BRICKS AND TILES.

221

machine, which combines the crushing rollers, pugmill, and brick-forming in one machine.
These machines are largely run upon, and have been
employed extensively by our great contractors, and
upon many public works—facts which give the best
assurance that they answer well.
One of these machines weighs about 3J tons, and of
this second size, with about 8 or 10 horse power, will
turn out from 75,000 to 90,000 bricks per week.
We now come to another class of machines working
Fig. 10.

with plastic clay, though capable of employing clay
nearly dry, or at least very stiffly tempered. The
machine shown in fig. 10 consists of a vertical pug-mill,
into the upper part of which the clay is fed, and in
which it undergoes tempering and mixing, and, on

222

RUDIMENTS OF T H E

reaching the bottom of the mill, is pressed into the
moulds, of the form and size of brick required, which
are arranged in the form of a circular revolving table.
As this table revolves, the piston-rods of the moulds
ascend an inclined spiral plane, and so gradually lift the
bricks out of the moulds, whence they are taken from the
machine by a boy, and placed on an endless band which
carries the bricks direct to the " waller." The speed of the
several parts is so arranged, that the operations of
pugging, mo aiding, and delivery proceed simultaneously in due order, the whole being easily driven by a
steam engine of about 6-horse power, which, at the
ordinary rate of working, will make 12,000 bricks per
day; or with 8-horse power from 15,000 to 18,000.
In consequence of the great pressure to which the clay
is subjected in the moulds, the bricks produced by this
machine may be made from stiffer clay, so that less
water has to be evaporated in the drying, thus saving
much of the time required for hand-made bricks, and
avoiding the risk of loss from bad weather.
One point of importance to remark as respects this
last class of machines, compared with the previous one,
is this—wire-cut bricks are smooth and perfect in form,
provided the clay be not only perfectly plastic, but perfectly uniform and free from adventitious particles.
If, however, the plastic clay contains gravelly particles, or be of such a quality that it is necessary to
mix it with ashes or (: breeze," then the section made
by the passage of the wire drags out and after it more
or less of these solid particles, and the faces of section
are rough and uneven; in such cases resort is best had
to those machines of pressure only.
In the following brick-pressing machine also, for
plastic clay, the moulded bricks are delivered by the

ATtT OF MAKING BRICKS AND TILES.

223

machine directly on to the horizontal belt that carries
them away; so that the labour of attendance is nearly
limited to feeding the tempered clay into the top
hopper. We are not aware to what extent as yet this
ingenious machine has been employed.
Figs. 11, 12, 13, and 14 illustrate a brick-pressing
machine recently patented by Mr. W. Longley, of Leeds.
The invention relates to an arrangement of brickmoulding machinery, whereby bricks are produced from
" wet" clay, having great solidity, with a smooth exterior, and containing a less amount of moisture than
those produced by hand, or by machinery at present in
use.
Fig 11 is a side elevation of the machine; fig. 12 is
a partial end elevation, showing in longitudinal section
the cylinder which carries the moulds, and presents them
successively to a conical hopper to be fed with clay; fig.
13 is a cross section of the mould-cylinder, showing its
connection with the hopper; and fig. 14 shows the
means used for locking the cylinder, so as to keep the
moulds stationary while being filled and discharged.
A A is the main framing of the machine, upon which
is mounted in suitable bearings a horizontal cylinder B.
This cylinder is cast with open ends, and it is fitted
near the middle of its length with a series of four
moulds, C C, arranged radially around it. These moulds
are formed by recesses cut through the periphery of a
projecting band a at that surrounds the cylinder, having
their ends closed by the rings b b (bolted to the cylinder) : a series of close chambers, D D, are formed in a
similar manner between the moulds for receiving steam
for heating the latter. Immediately above this concentric projection of the cylinder B, and in close proximity thereto, is situate the hopper E, in which a screw

AKT OF MAKING BRICKS AND TILES.

225

is mounted for forcing down the clay into the moulds
as they are presented to the former. Fitted into the
moulds are plungers, F, the stems of which project
through the inner periphery of the cylinder B, and are
intended for discharging the bricks from the moulds ;
the inner periphery of the cylinder B is also pierced to
receive the ends of a cruciform arrangement of steam
pipes, Q- (fig. 13), for supplying steam from a central
pipe running in the direction of the axis of the cylinder to the chambers D ; an intermittent axial motion is
given to the cylinder, for the purpose of bringing the
moulds severally under the hopper to be filled, and
subsequently under the action of a plunger the clay thus
filled into the mould presented to it is compressed
therein. "When this is effected, and the cam in its
revolution has passed out of action, the weighted crank
lever draws back the plunger 1T out of the mould. AnS
other movement of the cylinder B now takes place, and
the compressed brick is brought down to the position
for being discharged on to an endless apron 0. This is
effected by the stem of the plunger, F, of the mould,
being pressed upon at its rear end by the rocking lever H.
This rocking lever is mounted on a bent bracket arm
attached to the main framing, and it is provided with a
roller, which bears upon a rocking cam having a stud
pin on the framing for its fulcrum. This rocking cam is
jointed to a rod, which connects it with a rocking army
pendent from a bracket on the framing. The arm
carries a roller which bears against a cam on the cam
shaft; the revolution therefore of the cam shaft gives
a reciprocating motion to the cam H, thus causing
it to rock the lever H, and depress the plunger that has
been brought beneath its inner end. This depression
of the plunger effects the discharge of the brick, which
L3

226

RUDIMENTS OF T H E

is facilitated by the heating of the moulds through the
admission of steam as before explained. To prevent
the adherence of the clay to the compressing plunger,
that is made hollow, and steam is conveyed into it by
an arrangement of jointed steam pipes, as shown at fig.
11. The discharged brick is received on to an endless
apron, 0, which receives motion from the spur wheel
on the cylinder B, gearing into a spur wheel on
the axle of one of the carrying rollers of the apron.
The cylinder B is also furnished with a ring, in the
periphery of which are four notches, corresponding
with the moulds. These notches (see fig. 14) are for
the purpose of receiving the taper end of a locking bar
P, which, when it is desired temporarily to lock the
cylinder (as at the moment of filling, pressing, and
discharging the moulds), is thrust forward by a cam on
the cam shaft pressing upon a roller, mounted on the
end of the locking bar, which slides in guides provided
to receive it. The release of the cylinder is effected
by throwing back the locking bar by means of a
weighted crank arm, as in the case of the compressing
plunger.
This machine (fig. 15), the subject of a patent, is
made by Whitehead, of Preston; it works upon tempered clay also. The merits claimed for it consist in
simplicity of construction and efficient performance.
The junk of clay or brick may be previously moulded
as for other pressing machines, but with this machine it
is not absolutely necessary to previously mould the lump,
if only sufficient clay be supplied to make a brick, and
be simply placed in front of the piston; it then is forced
into the mould or die (of which there are four on a
revolving shaft) of the desired size, and any superfluous
bulk of the clay is cut off, thus making all the bricks

ART OF MAKING BRICKS AND TILES.

227

perfectly true and of uniform dimensions. During the
return of the piston the box of dies or moulds resolves
one-fourth of the way round, thus bringing another
empty mould, which has already been oiled and cleaned
by a self-acting lubricator, directly opposite the piston,
Fig. 15.

to receive the next brick. In the meantime, a selfacting push-plate forces the brick, already pressed, out
of the die upon a self-acting table prepared for carrying it away.
The following well-arranged machine belongs to the
class which can operate upon either plastic or dry clay,
but which is, in our opinion, best adapted to the former.
The makers and patentees, Messrs. Bradley and Craven,
of Wakefield, have had a large experience in machinery
of this sort. .
Simplicity of parts and strength are the main characteristics of this machine.
If the material be coarse or strong, it must be crushed-

228

RUDIMENTS OF T H E

before being passed into the hopper, into which it may
be delivered either with or without water.
. Two moulds receive the charge of clay at once.
While these are being filled, the two that had been
Mff. 16.

just before filled are being subjected to a considerable
pressure, and the two bricks that had just previously to
that been so pressed are in process of delivery, out of
the moulds and on to a flat belt which takes them
away.
For the production of smooth, well-squared facing
bricks this machine works extremely well.
We now arrive at the last class, namely, of machines intended specially to operate upon dry clay, or
nearly dry clay.
Amongst these we may notice the patent machine of
Hersey and Walsh, which has been recommended by a

ART OF MAKING BRICKS AND TILES.

229

competent authority—Mr.' Humphrey Chamberlain,
Consulting Pottery Engineer, formerly of Kempsey,
near Worcester.
This machine is stated to have been an American
invention, which attracted attention from the simplicity
of its movements and the enormous power it was capable of exerting with a small amount of friction. It
was found working successfully in the United States,
and arrangements made for its introduction in this
country. It produces an excellent article, and works
satisfactorily here also.
Some few alterations had to be made to adapt it
to English-sized bricks, as American bricks are little
more than one-third the cubical contents of the English.
The weight of these machines is about 25 tons, which
is necessary to withstand the enormous pressure they are
capable of exerting. They are made with any number
of moulds from 2 to 8. "With 6 moulds, and driven by
a 6-horse engine, to deliver 24 bricks per minute, one
machine is capable of giving 830 tons pressure on the 6
bricks; and if worked by a more powerful engine, the
pressure can be increased, only limited by the strength
of the machine. As few clays require more than 20 or
30 tons on a brick, from 4 to 5 horse power is ample.
The motions of this machine are performed by a pair
of cam wheels, the pressure being communicated by a
pair of rollers running on the cams, with the mould
pistons fixed on the shaft between them. The moulds
are raised and lowered by the same cams. The bricks
are delivered and the moulds re-fed with dry clay from
the hopper by a feeder worked by friction. The machine, after pressing 6 bricks, delivers them on a board
ready for removal, so that they go direct to the kilns
without being handled or injured. The whole machine

230

RUDIMENTS OF T H E

is fixed on one bed-plate, and is made of such strength
as not to be likely to get out of order.
The following machine will afford a sufficiently clear
notion of the construction, or at least the general principles of construction, of the great majority of dryclay brick-machines which have been brought into
successful action.
Fig. 17 represents the dry-clay brickmaking maFij. 17.

chine, of which Messrs. Bradley and Craven, of Wakefield, are the inventors and patentees.
One of the disadvantages or difficulties of making perfectly sound and solid bricks from completely dry clay,
however finely pulverised, is that the air lodged in the
interstices of the clay dust is sometimes not easily and
completely expelled by a single compression, but lodges
in one or more irregular cavities into which it has collected, and so leaves the brick hollow. One of the
main objects of this, machine is to obviate that evil,

ART OF MAKING BRICKS AND TILES.

231

which is proposed being accomplished by its possessing
the power of relieving each brick from pressure, and
again applying it, so as gradually to force out the air,
and finally consolidate the brick, and that to an extent
that a single pressure, though greater, and hence
exerting a greater strain on the machine, might not
accomplish.
The patentees state : " By this machine two or three
distinct pressures can be given to each brick. If two
pressures (that is, upward and downward) are sufficient
to produce a good article from the clay, then the machine makes two bricks at a stroke, or for every revolution one brick by each eccentric. If the clay is of such
a character that the whole of the air cannot be expelled,
or the dust sufficiently condensed to make a perfect
brick by two pressures, then a third is given by carrying the brick round under the second eccentric. With
most clays two pressures will be found sufficient. It is
only necessary to test a little of the clay to be worked
so that the machine may be adjusted to mould and
press from, any kind of earth equally good bricks. The
only change tor giymg three pressures is, to adjust
the machine to run faster, and change the inclined
plane for giving the upward or first pressure, and
delivering the bricks. The action of the machine is
easily understood. The clay being delivered by an
elevator from the crushing rollers into the hopper of
the machine in motion, the tappet wheel turns the
mould table the length of one mould. This action
delivers two empty moulds under the hoppers to receive
clay, delivers two bricks to the attendant, and gives a
powerful upward pressure to the clay received in the
moulds that have just left the hoppers. The table is then
for a moment stationary, while the two eccentrics give

232

RUDIMENTS OF T H E

the final strain on two bricks. When the eccentric
pistons are clear of the moulds the tappet again turns
the table one brick's length, and the same action is
renewed. During the time the eccentrics are giving
pressure, the table is held firmly by a stop, which is
then released."
The last of this class which we shall notice is the
dry-clay machine of Wilson, of Campbellfield Brickworks, Glasgow, which was exhibited in action at the
Exhibition of 1862.
The peculiarity of working of this machine is, that
the dry and pulverised clay prepared for being made
into brick is carried along automatically to the hopper,
and, just before being delivered into it, is subjected to
being blown upon by the waste steam discharged from
the non-condensing engine which drives the machine.
The result is a slight condensation of steam on and in
the pores of the clay, and a slight warming of the clay
itself. From this arises a much-increased tendency to
rapid and perfect agglutination in the clay when submitted to pressure in this state, between wet and dry,
and a much readier expulsion of the air involved in
the mass. There is not the slightest doubt of the
great advantage derived from this very simple mode
of treating the dry clay prior to compression.
There are several contrivances in Mr. Wilson's machine, as to details, also of value, especially one by
which the maximum pressure possible is so regulated that the destruction of the machine is guarded
against.
One great improvement yet remains to be made to
render perfect dry-clay brickmaking machines, namely,
to adapt to them the same method that was employed
by Mr. Brockedon, in his patent for compressing dry

ART OF MAKING BRICKS AND TILES.

233

powder of plumbago into a dense and solid block to be
sawed into pencils, namely, the operating the compression in a vacuum, so that the air involved between the
particles of dry clay (or dust, if quite dry) being thus
extracted, the mechanical pressure is free to act fully
and solely in producing condensation and agglutination
of the clay particles.
Any one of the brick machines of the first class,
down to fig. 8, inclusive, may, by a suitable alteration
of the discharging dies and receiving tables, be made
to express and form perforated bricks, moulded bricks,
drain or other pipes, or tiles of any sort, as in
Fig. 7.
We shall therefore confine our illustrations of tilemaking machinery, specially so designed, to two examples, viz., to fig. 18, the large drain-pipe machine of
Fig. 18.

Page and Co., of Bedford, which forces out a continuous hollow cylinder from the plasties clay (as at A,
fig. 19), and fig. 19.

234

RUDIMENTS OF T H E

The machine by "Whitehead, of Preston, for pressing
one end of the cylinder so cut off to a given length, as

at A, into the socket form, as at B, fig. 19, so that the
lengths shall go together with spigot and faucet joints.
Dies of various forms, prepared to adapt to any of
the brick or tile machinery, are supplied by the makers,

ART OF MAKING BRICKS AND TILES.

235

by which almost any form (solid or hollow, tubular or
multitubular^ i.e., perforated like "perforated brick"),
that can be produced by the advance of a given section
parallel to itself, may be formed. The figures in Fig. 7
show a few of the more usually employed sections—
those at the Tight being drain-pipes, those in the middle
for building? purposes, and the left-hand ones for roofing use.
In addition to the machines for brick and tile making,
which we have thus pretty copiously illustrated, there
are other machines almost innumerable for making
special forms in plastic or in dry clay, referable to the
great family of bricks and tiles. A great tribe of
these machines, to which our space forbids our making
any allusion, is employed in Great Britain and abroad
in the manufacture of encaustic, or inlaid, or intaglio
tiles for flooring and other architectural purposes.
Those who desire still more complete or enlarged information on the subject of this class of machinery should
consult the Practical Mechanic's Journal Record of the
Exhibition of 1862, Mr. D. K Clarke's " Exhibited
Machinery of 1862/' the Beports of the Juries of
Exhibition, 1862, and the volume of Abridgments of
Patents, relating to drain tiles and pipes, bricks, tiles,
and pottery, issued by the Patent Office, extending from
1619 to 1861. There have been many patents since
that date, and many descriptions of machines of more
or less value are also to be found scattered through the
British and foreign mechanical journals, in encyclopaedia
articles, &c. Though not important for those employing brick machinery at home, it may be desirable, for
the information of British colonists, that we should indicate the form of; portable high-pressure steam engine
most usually employed for actuating such. I t is that

236

RUDIMENTS OF T H E

shown in fig. 20, being one of this class of engines
manufactured by Clayton and Shuttleworth. When
bricks, &c, are required for a special contract or some
private work presenting but a terminable demand, such
Fig. 20.

portable engines are the best and cheapest in every
way; but, for a great and permanent brickmaking
establishment, engines upon fixed bed-plates or foundations are to be preferred.
In concluding these notices of the; apparatus of the
mechanical brick and tile marker, we must not omit to
call the reader's attention to probably the greatest improvement that has ever been made In the construction

ART OF MAKING BRICKS AND TILES.

237

of kilns, for at once drying and burning brick, viz.,
the patent brick-kiln of Hoffmann.
This kiln is, in fact, an admirable adaptation to brick
Fig. 21.

drying and burning of Siemens's regenerative principle
of furnace, as will be apparent from the following
Fig. 22.

account, abridged chiefly from a paper by Professor
James Thomson,.of Belfast. Fig. 21 is a half-plan on
top of the kiln, the other being a horizontal section at

238

RUDIMENTS OF T H E

the level of the flues, leading into the central chimneystalk, as seen in the vertical section, fig. 23. Fig. 22
is a diagram of the whole to a reduced scale, which is
Mg. 23,

referred to in illustrating the description of the mode
of working of the kiln.
The accompanying engravings illustrate this remarkable form of kiln, invented by M. Hofimann, of Berlin*
but patented in England by Mr. H. Chamberlain, who
supplies designs for their construction, &c. Some sixty
of these kilns are already at work on the Continent and
in Great Britain. The furnace or oven consists of a
circular channel, 0, of any section, which receives the
objects to be fired, introduced through doors in the
outside wall; the fuel is fed in by apertures formed in
the top of the arch. Flues lead from the bed of the

ART OF MAKING BRICKS AND TILES.

239

furnace to the smoke-chamber R, which surrounds
the base of the central chimney, the communication
with which can be cut off when required by means
of cast-iron bell-shaped covers. An intercepting
damper can be lowered or placed in grooves built
into the walls of the furnace immediately behind each
flue, so as to separate it at any distinct or equidistant
compartment. The fuel passes through apertures which
are constructed in the arch, and falls through channels
formed by the objects to be burnt to a chamber in the
bed of the furnace, from which a certain number of
small flues radiate to produce a free current from fire
to fire. In practice it is found bb^ter to divide the
kiln into twelve chambers, to which there are twelve
entries or doorways, and the same number of flues
communicating with the smoke-chamber, and just as
many openings in the arch for the reception of the
large intercepting dampers—thus the furrace can be
divided at any one of the twelve parts. J?or clearer
distinction, these compartments may be numbered, as
in fig. 22, from 1 to 12, of which two, Nos. 12 and
1, we will suppose are separated by the intercepting
damper. The objects to be burned may be bricks or
tiles, &c. Suppose the fire in full operation—the doors
leading to the compartments 1 and 2 being open, No. 1
for filling it with fresh goods, and No. 2 for taking
out those already burnt. The chambers Nos. 3, 4, 5,
and 6, which are all filled with burned goods, are
gradually cooling by the air entering through the doors
of Nos. 1 and 2, and as it passes on through warmer
and at last glowing ware, it will result that the kiln
fires are supplied with atmospheric air almost as hot as
the furnace itself. In chamber No. 7 the fire is burning, and when its contents have reached the desired

240

RUDIMENTS OF THE

temperature, No. 8 will have arrived at such a degree
from the absorption of the waste heat, that the fuel
introduced from the top k instantly inflamed.
The compartments Nos. 9, 10, 11, and 12, will be
dried off, and heated one after another by the waste
heat which passes through and expends itself on the
contents of these chambers, and on its arrival in No. 12,
meeting with the obstruction of the large damper,
it is conducted by the small flue to the chimney, with
its temperature again so lowered that it will only just
support the draught. No. 1 being now filled again,
the damper between 12 and 1 is lifted and lowered between 1 and 2. The bell damper above the mouth of
the flue No. 12 is lowered, and that of No. 1 lifted.
The doorway of No. 12 is then closed, and that of
the compartment No, 3 opened, the contents of which
will be sufficiently cooled to be taken out, while No. 2>
which is empty, can be filled again.
On the 5th of January, 1864, Professor J. Thomson,
of Belfast, read a paper on the manufacture of bricks,
before the Chemico-Agricultural Society of Ulster, in
which he referred at considerable length to the Hoffmann
oven. The following is an abstract of his paper:—
Having explained the chief methods in use for Working
the clay and forming it into bricks ready for the kiln,
he then turned attention to the great loss of heat which
occurs in the ordinary modes of burning bricks in common kilns. This loss is twofold. First, during the
burning of the bricks the air which has passed through
the fuel, or among the heated bricks, and the smoke,
including the gaseous products generally, passes away
from the kiln to waste at a very high temperature, even
at a red heat, during a considerable part of the process.
Secondly, when the bricks are raised to the high tern-

ART OF MAKING BRIGKS AND TILES.

241

perature required to burn them, and render them permanently hard, the great store of heat which they
contain is entirely thrown to waste while they are
left to cool. In this new kiln a remarkable economy
of fuel is effected, by saving the twofold loss of heat
already mentioned: first, it saves the heat of the
gaseous products of combustion and unconsumed air
passing through and away from the burning bricks, by
applying this heat effectively in drying the new fresh
bricks about to be burnt, and raising them up to an
incandescent temperature, so that only a very slight
addition of heat from ignited fuel directly is required to
complete their burning; and, secondly, it saves the
heat of the cooling bricks, after their having been
sufficiently fired, by applying it all again in warming
the air which goes forward to supply the fires; so that
the fuel is burnt with air already at nearly an incandescent temperature, instead of requiring, as usual, to
heat the air for its own combustion. Professor Thomson explained, as an example, the large kiln which
Mr. Moore was then constructing at his brick-works at
HayfieldPark, in the neighbourhood of Belfast. The kiln,
as will be seen, is built in the form of a large arched
passage, like a railway tunnel, bending round in going
forward on the ground till it closes with itself to form a
great circular ring-chamber, within which the burning
of the bricks is carried on. This ring-chamber may be
of any convenient dimensions, 160 ft. diameter being
a suitable size. Round its circumference there are
twenty-four entrance doorways, admitting of being
closed with temporarily-built bricks and clay, so as to
retain the heat and exclude all entrance of air by the
doorways so built up. The great ring chamber may now
bq conceived as consisting of twenty-four compartments
M

242

RUDIMENTS OF T H E

or spaces, with one of these doorways to each. In the
centre of the ring a high chimney is erected, and from
each of the twenty-four compartments of the annular
chamber an underground flue leads into the chimney.
There are, then, twenty-four of these flues converging
towards the centre like the spokes of a wheel, and each
flue has a valve, by which its communication with the
chimney can be cut off. Arrangements are made by
which a partition like a damper can be let down at pleasure, or otherwise placed, so as to cut off all communication between any of the twenty-four compartments of
the ring-kiln and the next one. Let us now suppose the
working of the kiln to have been already fairly established ; for, after being once kindled, the fire is never
extinguished, but the burning of new bricks and the
removal of the finished produce are carried on by a continuous and regular process from day to day. Two
adjacent compartments have this day their entrance
doors open, all the rest being perfectly closed. By
the arrangement of the valves in the flues, and the
large partition, the air which gets admittance alone
by the two open doors has to go round the whole
circuit of the ring-kiln in order to be drawn into the
chimney. From one of the two open compartments
men are taking out the finished and cooled bricks, and
in the other one they are building up newly-formed
unburnt bricks which are not yet quite dry. The air,
entering by these two compartments, passes first among
bricks almost cold and takes up their heat, and then
goes forward to warmer bricks, and then to hotter
and hotter, always carrying the heat of the cooling
bricks forward with it till it reaches the part of the
ring diametrically opposite to the two open and cold
compartments. At this place it gets a final accession

ATtT OF MAKING BEJCKS AND TILES.

243

of heat from the burning of a very small quantity of
small coal, which is dropped in among the bricks from
time to time by numerous small openings furnished
with air-tight movable lids. Thus at this part of the
kiln there is generated the full intensity of heat which
is required for the burning of the bricks. The hot air,
including the products of combustion, which, for brevity,
we may call the smoke, though it is really perfectly
gaseous and free from sooty particles, then passes forward to the bricks, which, by its continuous current,
are being heated; and it passes on among them from
hot bricks to those which are less and less hot, heating
them as it goes, and then passes on to those which are
still damp, drying them as it goes; and then it passes
to the chimney, in a state almost cold, and saturated
with the moisture, in the form of steam or vapour,
which it has taken from the damp bricks. On the
following day to that on which the operations just
described have been going on, the partition is shifted
forwards by the space of one compartment, and a
corresponding change is made as to the flue which is
to communicate with the chimney, and as to the pair of
compartments open for the admission of air and for the
removal of finished cold bricks, and the building in of
fresh damp bricks; and so the air, including the products
of combustion,* at the end of its circuit in the annular
chamber, just before passing off to the chimney, now
passes among the fresh bricks which were described as
built in on the yesterday of this new day. The place
where the small-coal fuel is thrown in is also advanced
round the circle by the stage of one compartment; and
so now the whole process goes on just as it did yesterday.
The fire thus makes a complete circuit of the annular
chamber in twenty-four working days. The whole
M2

244

VEtT OF MAKING BRICKS AND TILES,

process may be left dormant on Sundays, merely by the
closing of all apertures for the admission of the current
of air. The same kind of kiln, with the same process
of working, is applicable in the burning of lime; and
both for the brick-burning and the lime-burning, the
saving of fuel, relatively to what is consumed by the
ordinary methods, is such as to appear at first sight
almost incredible.
The Hoffmann or Chamberlain kiln is not so easily
applicable to burning lime as it is to brick, nor will it
answer without considerable modification for burning
thin and light tiles or pottery. There must be mass
enough in the goods to be fired to afford the requisite
magazine of absorbed heat to be afterwards used up,
and the draught must not be impeded as by the breaking
down of limestone when burnt into lime.
Those kilns are not necessarily made circular. They
are, indeed, now more usually rectangular, with
or without rounded ends, in plan. Wben originally
writing the preceding, the author of this chapter had
not himself seen those kilns at work, and hence quoted
from others as to their properties, &c. He has since,
however, had occasion, professionally, to make himself
fully acquainted with their construction and performance, and can indorse fully all that has been stated,
and, indeed/ might say much more in their commendation.
Many structural improvements and simplifications
have latterly been made in those kilns; but as the
patentee, Mr. H. Chamberlain, as a Pottery Engineer,
is professionally engaged in providing designs for those
who employ these kilns, it would not be fair that the
writer should here enter into further details.

APPENDIX I.
T H E following paper was read by Mr. Tomlinson at a meeting of the
Geologists' Association, on February 3, 1862:—
O N THE PLASTICITY AND ODOUR OF CLAY.

I t is a happy result of Bacon's method of inquiry that science is
not required to explain the causes of things, but to state the laws of
phenomena. Nevertheless, while these laws are obscure, and facts
are scattered, theory may often do good service by collecting and
marshalling them : for, as our great master of induction well observes,
*'Facts are the soldiers, but theory is the general." And again,
" Truth is more easily evolved from error than from confusion." That
is, a bad theory is better than none at all, for it serves to collect and
arrange the facts, and'thus makes them more easy to handle.
In these remarks must be found my excuse to-night for endeavouring to bind together some of the facts respecting a property of a
very common substance; namely, the Plasticity of Clay.
The more I consider this property the more wonderful and inexplicable does it appear. Take a mass of dry clay; it cracks easily,
and crumbles readily: add to it a certain proportion of water, and it
becomes plastic—it obeys the will of the artist or the artizan, who
can, out of this yielding mass, create new forms, or perpetuate old
ones. Drive off the water at a red heat, and plasticity is for ever
lost; rigidity takes its place: the clay is no longer clay, but something else. I t may be reduced to powder, and ground up with water;
but no art or science can again confer upon it its plasticity.
All this is very wonderful. There is another fact that is equally
FO : if we combine the constituents of clay in the proportions indicated by the analysis of some pure type of that substance, we fail to
produce plasticity. I have on the table specimens of Dorset clays
dry and crumbling; the same wet and plastic; and the same in the
forms of casts of fossils, which have been passed through the fire,

246

APPENDIX.

and have exchanged plasticity for rigidity. They are, in fact, in the
form of biscuit.
With respect to the temperature at which clay becomes rigid, we
have no accurate information. It is much lower than is generally
supposed, as will appear from the following experiment:—I pounded
and sifted some dry Dorset clay, and exposed it to a sand-bath heat
ia three portions varying from about 300° to 600°. Specimens were
taken out from time to time, and rubbed up with water, but they did
not lose their plasticity. Some clay was put into a test tube with a
small quantity of mercury, and heated until the mercury began to
boil. At this temperature (viz. 650°) the clay did not cease to be
plastic. The flame of a spirit-lamp was applied, and the tube was
heated below redness; after which the clay, on being mixed with water *
showed no sign of plasticity.
In experiments of this kind, the first action of the heat is to drive
off the hygrometric water. The clay then becomes dry, but is not
chemically changed; it does not cease to be plastic. On continuing
to raise the temperature, the chemically combined water is separated,
and the clay undergoes a molecular change, which prevents it from
taking up water again, except mechanically. With the loss of this
chemically combined water, clay ceases to be plastic.
It was, I believe, first noticed by Brongniart,* that we cannot produce plasticity by the synthesis of clay. The fire clay of Stourbridge,
for example, is a hydrated silicate of alumina, represented by the formula Al 2 O3, 2 Si O2 + 2 Aq. If we mix one atom of the sesquioxide of alumina with 2 atoms of silica and 2 of water, we get a
compound which cannot be called clay, since it is wanting in plasticity.
I t is quite easy to obtain either alumina or silica in the gelatinous
state; but we cannot obtain them in the plastic state.
Clay is almost the only substance in the mineral kingdom that possesses plasticity. In loam, if the sand be in large proportion, and in
marl, if calcareous matters abound, so as to deprive either material
of plasticity, it ceases to be clay. There are also certain silicates of
alumina which are not plastic ; such as bole, lithomarge, and fullers'earth. Bole consists chiefly of a hydrated bisilicate of alumina, in
which a portion of the alumina is replaced by sesquioxide of iron.
Lithomarge also contains iron, and is sometimes so compact as to be
used for slate-pencils. Fullers'-earth contains lime, magnesia, and
iron, in addition to its principal ingredients.
* « Traill des Arts C&ramiques." Paris, 1844. Vol. i. p. 82.
*

APPENDIX.

247

. There is probably no substance so indeterminate in its composition
as clay. Regarding it, as Lyell does,* as " nothing more than mud
derived from the decomposition of wearing down of rocks," it must
necessarily contain a variety of substances; such as oxide of iron,
lime, magnesia, potash, silica, bitumen, fragments of undecomposed
rock, &c. These substances impair the plasticity of the clay, and
impress upon it certain characters which are of more importance to
the manufacturer than to the chemist, or the geologist. Brongniartf
enumerates, and gives the analyses of no fewer than 167 clays and
28 kaolins, all of which are in use in the arts in different parts of the
world. They probably all differ in plasticity, but they all possess i t ;
and at a high temperature exchange it for rigidity. A rough method
of measuring the plasticity of different clays is to note the length to
which a cylinder of each can be drawn out in a vertical direction
without breaking. In such a comparison, the clays must, of course,
be worked equally fine, and contain the same proportion of water.
I t is commonly stated that the ingredient that confers plasticity
on clay is its alumina; and yet, strange to say, pure alumina alone
whether gelatinous, or after having been dried and ground up with
water for a long time, never gives a plastic paste. Indeed, nothing
can be conceived less plastic than gelatinous alumina, as may be seen
from the specimens on the table. We may drive off most of the water
from this gelatinous hydrate, but it will not become plastic. Or we
may form clay by mingling solutions of the silicate of alumina and the
aluminate of potash. You see they are perfectly fluid. I apply the
heat of a spirit-lamp, and we get an opalescent gelatinous mass, but
still no plasticity. "We have, indeed, formed a gelatinous clay.
We cannot say that the gelatinous state of alumina is the cause of
plasticity in clay; for silica may be made as gelatinous as alumina,
and silica is certainly not the cause of plasticity. I t may be that the
strong affinity of alumina for water (retaining a portion of it even
when near a red heat) may be the cause of this property—just as
turpentine renders wax plastic; and water and gluten confer the
same property on starch.
We have seen that clay ceases to be plastic when its chemically
combined water has been driven off. Still, however, water cannot be
said to be the cause of plasticity, as a general property, since we
have, in melted glass, a more perfect example of plasticity even than
* "Manual of Elementary Geology" (1855), p. 11.
f " Des Arts Ce'ramiques," Atlas of Plates.

248

APPENDIX.

in clay; and few substances are more plastic than sealing-wax at a
certain temperature.
A clear idea of plasticity, and of some of the other mechanical
properties of matter, may probably be gained by considering them as
variations of the forces of cohesion and adhesion, and by bringing
these, in their turn, under Newton's great law of attraction, which,
whether exerted between atoms or masses, is directly as the mass,
and inversely as the squares of the distances.
Now, if we suppose the distances between the molecules of matter
to be 1-millionth or billionth, or 2, 3, 4, 5, 6, &c, millionths or billionths of an inch asunder, the intensity of their attractions will be 1,
Jth, -g-th, xVh, &c., or, to represent it in a tabular form :—
Distances
1 2 3 4 5 6 7 8 9 10, &o.
Intensities of attraction 1 i -g- T V "gV "sV "?V "sV -ir T5~o> &cSuppose the molecules to be of the same density, but at different
distances apart, as represented in the upper line. At the distance of
1-millionth of an inch we get an intensity of attraction represented
by 1. At 2-millionths of an inch the force of attraction is only onefourth. Now, the idea is this, that the mechanical properties of
matter,—such as porosity, tenacity, hardness, brittleness, plasticity,
elasticity, &c, depend upon variations in the attractive force of the
molecules according to the distances apart of such molecules. Thus,
if the molecules of clay require to be 5-millionths of an inch apart
in order to produce plasticity, the intensity of attraction between
them will be represented by -g15-th; but if such clay be passed through
the fire, and the molecules, in consequence of the escape of water,
be brought nearer together, and rigidly fixed at 4-millionths of an
inch asunder, the force of attraction will then be ^ t h .
Now, the method of arranging the particles of clay at that precise
distance that shall impart plasticity, is one of Nature's secrets that
we have not yet succeeded in penetrating. It may be that the circumstances under which clay is formed and deposited, or the time that
has elapsed since its formation, or the pressure of the superposed
layers, may have so arranged the particles as to enable them to
become plastic when the proper proportion of water is added. I t
may be that a certain state of disintegration is required on the part
of the alumina and the silica, so that their proximate elements shall
be neither too fine nor too coarse; or it may be that the silica, in
combining with the alumina, separates the atoms of the latter to precisely those distances required for the development of the property;

APPENDIX.

249

or, lastly, the presence of a small portion of animal or other organic
matter in clay may have something to do with this remarkable pro«
perty.
An extensive series of experiments, by Delesse,* show the presence
of animal matter in quartz and various rocks, where its presence had
not previously been suspected; and this may have as important an
effect in modifying the properties of a mineral as the presence of
minute portions of bodies, formerly entered as impurities, has in
producing pseudo morphous crystals.
Still, the question recurs, Why is not a clay artificially formed
from pure materials plastic ? The answer is, that we do not know all
the conditions of plasticity. We do know the conditions under which
some mechanical properties exist—such as the hardness of steel, the
brittleness of unannealed glass—and can confer or remove such properties at pleasure. But with respect to plasticity, we can only confer
a factitious property of this kind on mineral substances by taking
advantage of another property which it somewhat resembles, namely,
viscosity or viscidity. Viscosity differs in plasticity in this, that the
viscous body does not retain the form impressed upon it when the
force is removed, as a plastic body does. The materials of the old
soft porcelain of Sevres had no plasticity; but this property was conferred by means of soft soap and parchment size.f
Without speculating further on the nature of plasticity, I may
remark that in the ancient philosophy the word was one of power.
Derived from the Greek irXaaativ, or TrXarrfiv, " to form," or " to
create," it not only included the arts of modelling in clay, but also
sculpture and painting, and, by a refinement of language, poetry and
music. Plato and Aristotle even supposed that a plastic virtue
resided in the earth, or did so originally, by virtue of which it put
forth plants, &c.; and that animals and men were but effects of this
plastic power. They did not suppose the world to have been made
with labour and difficulty, as an architect builds a house; but that a
certain " efficient nature" {natura effecirix) inherent and residing in
matter itself, disposed and tempered it, and from it constructed th
* " De l'azote et des matieres organiques dans l'ecorce terrestre."—Annales des
Mines, xviii , 1860.
t Brongniait (''Des Arts Ceramiqnes") eays that the old porcelaines tendreswere
formed of 22 percent, of fused nitre, 60 of Fontainebl^au sard, 7*2 or salt, 3 6 of alum.,
3*6 of soda, and 3 6 of gypsum. These ma erials were fritted and ground, and 75
parts taken, to: whi(h wtre added white chalk 17 parts, marl 8. This mixture was
ground, sifted very fine, and made up imo a paste with l-8th soft soap and size, or, at
a later period, with gum tragacanth.

M 3

250

APPENDIX.

whole world. Aristotle distinctly recognises mind as the principal
and directing cause, and natura as a subservient or executive instrument. Even in later times men have contended for the existence of
a plastic nature, or incorporeal substance endowed with a vegetative
life; but not with sensation or thought, penetrating the whole universe, and producing those phenomenal^ matter which could not be
solved by mechanical laws. The learned Cudworth supports this
view,* and the discussions into which it led him and other metaphysicians form a curious chapter in the history of the human mind. In
England we do not now retain the term plasticity, except as a physical property of matter; -j* but in Germany it has still an extensive
figurative meaning. The word plastisch still means bildend or
schbpferisch (i.e. " creative"); and it is still applied not only to sculpture, but also to painting, poetry, and music. A German well understands the expression " plastische Gedanken," or " plastic thoughts."
Before concluding, I would refer to another property of clay, which
seems to me as wonderful as its plasticity; namely, its odour when
breathed on, or when a shower of rain first begins to wet a dry clayey
soil. This odour is commonly referred to alumina, and yet, strange
to say, pure alumina gives off no odour when breathed on or wetted.
The fact is, the peculiar odour referred to belongs only to impure
clays, and chiefly to those that contain oxide of iron. This was
pointed out by Brongniart as far back as 18] 6,J who also remarked
that minerals which do not contain alumina, such as pulverised chalcedony, possess this remarkable property.
I have found that a pure kaolin, ground up in a mortar with a
small quantity of water, emits a slight odour, which, however,
becomes much more sensible if a little sesquioxide of iron be
added.
Smooth quartz pebbles when rubbed together give an electric spark,
and a fetid odour. It is commonly supposed that sea-side pebbles
alone possess this property ; but the odour belongs equally to those
found among gravel overlying the chalk, and in ploughed lands where
the surface is exposed to all the vicissitudes of the weather. It is quite
possible that the odour of these pebbles may hereafter be traced to
the presence of organic matter; but 1 cannot resist the reproduction
here of a suggestive hint given me by my friend Professor Bloxam,
* See " The True Intellectual System of the Universe," by Ralph Cudworth, D.D.,
1678. A reprint has been published by Tegg, in which see Vol L, p. 226, et *eq.
t Dr. Johnson defines pja»tic as " having the power to give form."
J " Dictionnaire des Sciences NatureJles," art. Argile.

APPENDIX.

251

who is reminded by the spark and odour from these pebbles of the
presence of ozone.
What, again, is the cause of the odour in the narrow parts of stone
buildings, not of new buildings alone, but of old ones, as in the staircases of old cathedrals ?
I do not attempt to reply to these questions. I t requires some
amount of knowledge and experience to put them—but how much
more to answer them!
ON DRYING BRICKS.

{Extractedfrom Noble}s "Professional Practice of Architects" p. 143.)
" The observations by Richard Neve, above a century since, upon
stock bricks, will illustrate the subject: ' When the hack is as high as
they think fit, they cover them with straw till they are dry enough to
b u m , ' &c, &c. He proceeds: f A brickmaker being sent to Rumford, in Essex, went to work unadvisedly, and laid them abroad* in a
place to dry; but the sun, about ten o'clock, began to shine very hot,
and the whole quantity of bricks burst to pieces, so that he was forced
to go to work again: and then, before the sun shone too hot, he
thatched or covered them over with straw till the next morning,
when removing it, they did very well when set on the hack; and
when burnt, were curious red bricks, which would ring when hit with
any hard thing.'"
O N THE USE OP COAL DUST IN MAKING CLAMP.BRICKS.

(Retractedfrom Noble's " Professional Practice of Architects" p. 153.)
" Natives should be employed (in making bricks in Wales) in the
manufacture, in preference to London hands, as the former use coal
dust in preparing the earth, and not breeze (ashes), as about London;
and provided an undue portion of coal is used, a whole clamp would
be destroyed, of which there was an instance at Lampeter (Cardiganshire). An Islington brickmaker was sent to Wales, and as he was
too conceited to make inquiries, or to receive information, set light
to a clamp he had prepared with coal, being 70,700; and in a very
short time the whole kiln was in one general blaze. The man being
alarmed, took to his heels, and, unlike Lot's wife, he turned not
back, neither looked behind him. Even from the heights leading to
Landovery the reflection was quite enough for him \ nor did he stop

252

APPENDIX.

till he reached London, being, as he said, ' afeared' they would catch
him and put him in prison! "

BRICKMAKING AT GREAT GRIMSBY, LINCOLNSHIRE.

Large quantities of bricks have been made during the last few
years at Great Grimsby, for the Dock Company, from the Humber
silt. These bricks are remarkable for their colour, which varies in
the same brick from dark purple to dirty white, passing through
various shades of blue, red, and yellow, in the space of two or three
inches. The silt, when first dug out of the bed of the Humber, is of
a dark blue colour, which soon, from exposure to the air, changes to
a brown.
The bricks made for the Dock Company were burnt in close
clamps—fired with layers of small coal, but without coal-dust or
ashes being mixed with the clay as in London brickmaking. With
the first clamps there was much waste, the quantity of fuel being
excessive, and the bricks were cracked and made brittle in consequence ; but the experience obtained by the first trials has led to the
production of a sound well-burnt brick, with, however, the peculiar
colour above mentioned.
Considerable quantities of bricks have been lately made for sale at
Great Grimsby, and burnt in clamps with flues, as in kiln burning,
which method appears to be attended with less waste than close
clamping.
The slack or small coal used for fuel may cost from 2s. fid. to &s.
per 1,000 bricks. The cost of clay getting, tempering, moulding,
and drying, is about 85. Qd. per 1,000. The moulds used are of
wood, plated with iron. The process employed is that known as
slop-moulding.
Kilns as well as clamps are used in this part of Lincolnshire, their
construction being similar to that of the kilns in general use in the
Midland Counties.
BRICKMAKING IN SUFFOLK.

Two kinds of bricks are made in Suffolk, viz., reds and whites. The
latter are much esteemed for their shape and colour, and large quantities are annually sent to London, for facing buildings of a superior
class.

APPENDIX.

253

Clay.—The supplies of brick-earth are chiefly derived from the plasuo
clays lying above the chalk, although the blue clay is occasionally used.
The clays in most parts are too strong to be used as they rise,
and have consequently to be mixed with a white loam or a
milder earth.
Tempering.—The clay is turned over in February and March, and in
some parts of Suffolk it is passed through the wash-mill, but
this is not generally the case.
Tempering is generally performed by spade labour, but the
pug-mill is sometimes used, although not commonly, for white
bricks; it is, however, used for all other white ware.
Moulding .—The brick mould is of wood, shod with iron; the dimensions vary slightly according to the nature of the clay, but are
usually as follows: 9Jt,hs long by 4yf ths wide and 3J- deep.
There is no hollow formed in the bottom of the brick for the
mortar joint. Brass moulds are unknown.
Sea sand is used in the process of moulding, for sanding the
mould and the table.
The strike is used for taking off the superfluous clay from the
mould. The use of the plane is not known.
Drying.—The bricks are not dried on flats as in the Midland Counties, but are taken directly from the moulding stool to the hacks.
Sheds are used in some yards, and drying houses with flued
floors are used in winter for pantiles and kiln tiles, but not for
bricks.
The length of a hack is about 70 yards, and each moulder
will keep four hacks going.
The time required for drying in the hacks of course varies
according to the weather, but may be stated on an average at
about eighteen days for red bricks. White bricks dry somewhat
quicker.
The contraction of the clay in drying amounts to about J in. in
the length of a brick, and, if properly burnt, the shrinkage in
the kiln is imperceptible.
The weight of a brick, when first moulded, is about 8 lbs.;
when dried, about 7 lbs.; and when burnt, about 6 lbs.; but
much depends upon the nature of the earth.
Burning.—The construction of the kiln is quite different from that of
the kilns used in other parts of England, having two arched

254

APPENDIX.

furnaces running its whole length underneath the floor, which is
formed of a kind of lattice work, through the openings of which
the heat ascends from the furnaces below.
The cost of erecting a kiln to burn 50,000 whites is about
£145. A kiln to burn 35,000 reds costs about £100.
The bricks are commonly set in the kiln in bolts two bricks
long by ten on; but some brickmakers prefer to cross them in
the alternate courses, in order to admit the heat more freely.
The fuel used is coal, and the quantity consumed is about
half a ton per 1,000 for white, and 7 cwt. per 1,000 for red,
bricks.
The time of burning is about CO hours for white, and 40
hours for red, bricks ; white bricks requiring a greater heat than
the red ones to bring them to their proper colour. The coal
costs from 15s. to 16s. per ton.
Cost of Manufactured
The selling prices vary from £ 1 10s. to £ 2 per 1,000 for reds, and
from £2 2s. to £3 per 1,000 for whites.
Of red bricks two qualities only are distinguished, viz., outside and inside; of white, four qualities are distinguished, viz.,
best, 2nd, 3rd, and murrays.
The price of the ordinary red brick is about £ 1 10s. per 1,000,
jand the cost may be thus divided:—
Clay digging, per 1,000
.
.
.
.
Tempering, ditto
Moulding, ditto
Drying, ditto
Barrowing from hacks and setting kiln ditto
Burning, ditto
Drawing kiln, ditto
Stacking, ditto

.
.
.
.
.
.
.
.

£ s. a.
0
0
0
0
0
0
0
0

2
1
5
0
1
1
0
0

6
0
0
6
0
3
8
3

Cost of labour per 1,000 £0 12 2
Coals, about
.
.
.
.
.
. 0 6 0
Duty
0 6 H
Kent, tools, contingencies, and profit
.
. 0 5 8J
Selling price at the yard, about £ 1 10

0

* These estimates belong to the date of the First Edition of this. work.

APPENDIX.

255

White bricks are made in many parts of England, but the Suffolk
whites have the pre-eminence over all others.
The white bricks made near Lincoln are remarkable for swelling
when laid in work, which causes them to throw off the mortar joints,
and renders it impossible to make use of them in good work.
The clay from which these bricks are made extends from the
Witham northwards as far as the Humber, and, so far as we are
aware, possesses the same property throughout this distance, the
bricks made from it at various points between the Witham and the
Humber having the common defect of swelling after burning. A
curious specimen of this may be seen in a large chimney at Saxilby,
which has a complete twist, from the irregular swelling of the brickwork.
The peculiar property of swelling after burning is not confined to
the Lincolnshire white clay. The author was informed some years
ago, by Mr. Vignoles, C.E., that some of the bricks made on the
Midland Counties Line of Railway, between Rugby and Derby, had
the same defect.
For the above particulars respecting the Lincolnshire white bricks
we are indebted to Mr. William Kirk, of Sleaford.

ON THE MAKING AND BURNING OE DRAIN TILES.

Extracts from a communication by Mr. Law Hodges, published in
the Journal of the Royal Agricultural Society of England, Vol. V.
Part II. :—
" Reflecting on these obstacles to universal drainage, where
required, I conferred with Mr. John Hatcher (brick and tile maker,
and potter, Benenden, Kent), on the possibility of erecting a kiln
of common clay that would be effectual for burning these tiles, and
of cheap construction—and the result was the building one in my
brickyard in July last, and the constant use of it until the wet
weather at the commencement of this winter compelled its discontinuance, but not until it had burnt nearly 80,000 excellent tiles;
and in the ensuing spring it will be again in regular use.
" I shall now proceed to take in order the six points enumerated
under the 9 th head of the Prize Essays for 1845, as printed in the
last volume of the Royal Agricultural Society's Journal, viz.:—

256
Li

APPENDIX.

1st. Mode of working clay according to its quality.
" 2nd. Machine for making tiles.
" 3rd. Sheds for drying tiles.
" 4th. Construction of kilns.
" 5th. Cost of forming the establishment.
" 6th. Cost of tiles when ready for sale.
" 1st Point. Working the clay.
" All clay intended for working next season must be dug in the
winter, and the earlier the better, so as to expose it as much as possible to frost and snow. Care must be taken, if there are small
stones in it, to dig it in small pits, and cast out the stones as much
as possible, and also to well mix the top and bottom of the bed of
clay together. I t is almost impossible to give minute directions as
to mixing clay with loam, or with marl when necessary, for the better
working it afterwards, as the difference of the clays in purity and
tenacity is such as to require distinct management in this respect in
various localities; but all the clay dug for tile-making will require to
be wheeled to the place where the pug-mill is to work i t ; it must be
there well turned and mixed in the spring, and properly wetted, and
finally spatted down and smoothed by the spade, and the whole heap
well covered with litter to keep it moist and fit for use through the
ensuing season of tile-making.
" 2nd Point. Machine for making tiles.
" Eor the reasons already alluded to, I prefer Hatcher's machine*
Its simplicity of construction, and the small amount of hand labour
required to work it, would alone recommend i t ; for one man and
three boys will turn out nearly 11,000 pipe tiies of 1 in. bore in a day
of ten hours, and so in proportion for pipes of a larger diameter; but it
has the great advantage of being movable, and those who work it draw
it along the shed in which the tiles are deposited for drying, previously
to their being burnt: thus each tile is handled only once, for it is
taken off the machine by the little boys who stand on each side, and
at once,placed in the rows on either side of the drying shed, thus
rendering the use of shelves in the sheds wholly unnecessary, for the
tiles soon acquire a solidity to bear row upon row of tiles, till they
reach the roof of the sheds on either side; and they dry without
warping or losing their shape in any way.
"The price of this machine is £25, and it may be proper to add,
that the machine makes the very best roofing tiles that can be made,
and at less than half the price of those made by hand, as well as

APPENDIX.

257

being much lighter, and closer, and straighter, in consequence of the
pressure through the die.
" It is necessary, in order to ensure the due mixing of the clay, as
well as "to form it into the exact shape to fill the cylinders of the
machine, to have a pug-mill. Messrs. Cottam and Hallen make these
also, and charge £10 for them. This mill must be worked by a
horse ; in general one day's work at the mill will furnish rather more
prepared clay than the machine will turn into tiles in two days
" 3rd Point. Sheds for drying.
" The sheds necessary for this system of tile-making will be of a
temporary kind: strong hurdles pitched firmly in the ground in two
parallel straight lines, 7 ft. apart, will form the sides of the sheds,
and the roof will be formed also of hurdles placed endways and tied
together at the top, as well as to the upper slit of the hurdle, with
strong tarred twine, forming the ridge of the roof exactly over the
middle of the shed. They must then be lightly thatched with straw
or heath, and the sharpness of this roof will effectually protect the
tiles from rain. Two of these sheds, each 110 ft. long, will keep
one of the kilns hereafter described in full work.
" N.B.—These sheds should be so built as to have one end close
to the pug-mill and the clay-heap, only leaving just room for the
horse to work the mill, and the other end near the kiln. Attention
to this matter saves future labour, and therefore money.
" 4th Point. Construction of kilns.
" The form of the clay kiln is circular, 11 ft. in diameter, and
7 ft. high. I t is whollv built of damp earth, rammed firmly together,
and plastered inside- and out with loam. The earth to form the walls
is dug out round the base, leaving' a circular trench about 4 ft. wide
and as many deep, into which the fire-holes of the kiln open. If wood
be the fuel used, three fire-holes are sufficient; if coal, four will be
needed. About 1,200 common bricks are wanted to build these
fire-holes and flues; if coal is used, rather fewer bricks will be
wanted, but then some iron bars are necessary—six bars to each firehole.
" The earthen walls are 4 ft. thick at the floor of the kiln, are
7 ft. high, and tapering to the thickness of 2 ft. at the top; this
will determine the slope of the exterior face of the kiln. The inside
of the wall is carried up perpendicularly, and the loam plastering
inside becomes, after the first burning, like a brick wall. The kiln
may be safely erected in March, or whenever the danger of injury

258

APPENDIX.

Fig. 1. Plan of Kiln at A B ; fig. 3.

Fig. 2. Flan of Top of Kiln,

259

from frost is over. After the summer use of it, it must be protected
by faggots or litter against the wet and the frost of winter.
" A kiln of these dimensions will contain—
47,000 1-in. bore pipe tiles.
32,500 1J
20,000 If
12,000 2 |
and the last-mentioned size will hold the same number of the inch
pipes inside of them, making therefore 24,000 of both sizes. In good

260

APPENDIX.

Fig. 4.

weather this kiln can be filled, burnt, and discharged once every fortnight ; and fifteen kilns may be obtained in a good season, producing—
705,000 1-in. pipe tiles.
Or 487,500 1J „ „
Or 300,000 1 | „ „
and so on in proportion for other sizes.
" N.B.—If a kiln of larger diameter be built, there must be more
fire-holes, and additional shed room.

261

APPENDIX.

" 5 th Point.

Cost of forming the establishment.

The price charged by Messrs. Cottam and Hallen for the machine,
with irs complement of dies, is
.
'.'
£25
Price of pug-mill
10
Cost of erecting kiln
5
Cost of sheds, sti aw
10
50

(The latter item presumes that the farmer has hurdles of his own.)
" 6th Point. Cost of tiles when ready for sale.
" As this must necessarily vary with the cost of the fuel, rate of
wages, easy or difficult clay for working, or other local peculiarities,
I can only give the cost of tiles as I have ascertained it here according to our charges for fuel, wages, &c, &c. Our clay is strong, and
has a mixture of stones in it, but the machine is adapted for working
any clay when properly prepared.
" It requires 2 tons 5 cwt. of good coals to burn the above kiln
full of tiles. Coals are charged here at £1 8*. per ton, or 1,000 brush
faggots will effect the same purpose, and cost the same money; of
course some clays require more burning than others; the stronger
the clay the less fuel required.
" The cost of making, the sale prices, and number of each sort that
a waggon with four horses will carry, are as follows:—
1-in. pipe tiles
l£
„
If
„
2£
„
2f
„
Elliptical tiles

Soles

. . . . .

Cost.
Sale
s. d.
4 9 per 1,000
6 0
„
8 0
„
If) 0
„
12 0
„

Price.
s.
12 .
14 .
16 .
20 .
24' .
24)

Waggon
holds—
8,000
. .
7, 00
. . 5,000
. . 3,500
. . 3,000
.

.

10J* ' '

2l000

" All these tiles exceed a foot in length when burnt.
" The cost price alone of making draining tiles will be the charge
to every person making his own tiles for his own use. If he sell them,
a higher price must, of course, be demanded to allow for so-me profit,
for credit more or less long, for bad debts, goods unsold, &c. &c.;
but he who makes his own saves all expense of carriage, and, as his
outlay will not exceed £50, the interest on that sum is too trifling to
be regarded, and he has no ad ditional rent to pay; and after he has
made as many tiles as he wants, his machine and pug-mill will be
as good as ever, with reasonable care, and will fetch their value.",

APPENDIX II.
THE SCIENCE OE BRICKMAKING.

IT has been said by the author of this volume, in his preface, that
the science of brickmaking has yet to be formed and written.
This is no doubt in one sense true, though it must be remarked
that, inasmuch as the art of the brickmaker is to be viewed in its
chemical and physical relations as only the humblest branch of that
of the potter or porcelain manufacturer, the saying so is not to discredit the vast and wide-spread importance of exact knowledge to
the brickmaker, nor of the value of his universally-diffused and indispensable art.
The manufacture of pottery, in all its branches, having been the
subject of lengthened and important scientific labours at the hands
of successive able men of science, amongst whom are Reaumur,
Bottcher, Brongniart, Malaguti, and Salvetat, as well as of the
tentative and technological labours of innumerable manufacturers,
amongst whom Cookworthy, Chaffers, Wall, Wedgwood, Minton,
and others stand pre-eminent, in England alone, it cannot be said
that pottery in general is devoid of a formed and established science,
though very much remains to be discovered over its wide domain of
theory and practice. This being so, and very much of the science of
the porcelain manufactory being directly applicable and available in
the brick-field (if indeed the brickmaker himself possess the requisite
foundation in general scientific education, especially in chemistry and
physics), it is only true in one sense that no science of brickmaking
yet exists, namely, in the sense that the knowledge we already possess
of the science of the ceramic arts has not yet been systematised
and applied in a special manner to the brickmaker5 s art. To attempt
to supply this want in the present little volume is impossible.
Three such volumes would scarcely afford sufficient space to treat of
the science of brickmaking in a systematic and complete manner.

APPENDIX.

263

Still it seems undesirable that in an elementary outline of this art
so little should have been given in the original text, even as a sketch,
of some salient points which such science presents. We shall attempt
this, however incompletely.
The brickmaker deals with natural clays only, the constitution of
which, when more or less ascertained in respect to his object, he may
modify by the addition of other mineral bodies, such as sand, ashes,
&c, or by the mechanical extraction of naturally-mixed matter, as
sand, pebbles, pyrites, &c, and whose physical qualities he may alter
by mechanical means—grinding, " slip-washing," &c.
The choice of a clay that shall answer well for the brickmaker's use
cannot be made before trial, by any amount of examination, unless
we also possess a chemical analysis of the natural material. Aided
by that, it is quite possible upon tempering a ball of the clay, observing its plasticity and body, and then wetting further a little bit, and
rubbing it between the thumb and the forefinger, to tell with a great
degree of certainty whether it will make good brick or not; either
alone or, as is almost always the case, mixed (and so altered) either
with more sand or more tough clay, and occasionally with coarselyground coal, or breeze, or ashes, &c.
Clays are essentially chemical compounds, and this is true, whether
they be or be not always mere mud from disintegrated rocks, as
some geologists have probably erroneously supposed. They are in fact
true hydrates, and have the general constitution (S 0 + Al2 0 8 ) +
H O + U O ; the last or accidental base or bases being usually calcium, magnesium, manganese, or iron, or more than one of these;
and they may be divided into four great classes. Pure aluminous
clays and pure magnesian clays, both hydrated: these are rare, the
latter especially so—when indurated, constituting meerschaum; and
we may pass them without further notice here. They belong, not
to the brickmaker, but to the porcelain-maker.
More widely spread for our use, we have the ferruginous clays,
which have generally this combination (Si 0 + (Al2 03 + Ee2 Os)
± F e O + N O + K O ) + H O ; and the calcareous clays (Si 0
+ (Al2 0 3 + Fe 2 0 8 ) + (Ca 0 + C 0 2 + Mg 0 + C 0 ? ) ± Fe +
N 0 + K 0 ) -f H O. Either of these may be mixed with more or
less siliceous sand, and when this is in considerable proportion the
clay is a loam.
At a red heat they lose most of their combined water, losing more
or less hygroscopic water at 212°; and at a bright yellow or white

264

APPENDIX.

heat, or rather below it, they bake into pottery or brick. And
while many of the clays rich in alumina, silica, and iron do not fuse,
or but very slowly, at the melting-point of cast-iron, most of the calcareous clays melt at or below this temperature, or at least agglutinate, assuming the vitreous texture if the heat be long continued.
The following table contains the analysis of ten natural clays,
which gives a pretty clear notion of their.usual range of constitution ;—
No. 1 is a fuller's earth, analysed by Dr. Thomas Thomson.
No. 2. A sandy clay, known as the " ball-clay " of the Potteries,
and used for salt-glazed ware •, analysed by Cowper.
No. 3. An ash-white pipe-clay.
No. 4. A grey-blue clay.
No. 5. A red-brown Glasgow clay.
No. 6. A yellow midland counties clay, used for brick and for
Rockingham pottery.
(All these analysed by Cowper, Phil. Mag. xxxi. p. 435.)
No. 7. A marly English clay; analysed, with the following, by
Berthier.
No. 8. A marl from Vitry, Department of Marne; used in Paris
foundries.
No. 9. A German clay {Loess of the Rhine), used at Bonn; analysed
by Kjenulf.
No. 10. A loam, analysed by Dr. Urc.

TABLE 3.

Constituents.

SiO
A^ 0 8
Ca 0

No. l.

No. 2.

No. 3.

No. 4.

No. 5.

No. 6.

44*00 66-68 53-66 46-38 49-44 58-07
36-06 26-08 3200 38-04 34-26 27*38

No. 9.

10-40 J

4-08

0-84

0-40

1-20

1-48

trace

trace

trace

1-94

Fe208

i

0-50
46-50

> •

20-16 39-80

fed

0-04
2-20

3-50

4-21

1-26

FeO

9-97 11-20*
0-02

trace

2-00

No. 10.

f 58-97 33-06

28-50

38-40

MgO

6-01

4-25
0-27

1-04

7-74

3-30

5-20

2-00
Alkalies NO + KO and Water..

No. 8.

32-80 ]

Ca 0 + C0 2

MgO + C0 2

No. 7.

3-00
14-50

5-14 12-08 13-57 , 5-14 j 10-30
•'WitkTesOs.

19-60

4-00

1

3-32 , 10-00

I

265

1

266

APPENDIX.

Most of these clays, as found in nature, contain some organic matters
and pebbles of foreign bodies. Unless these are of hard pyrites or
limestone, they are unimportant. Flinty pebbles can generally be
crushed in the clay-mill, or taken out by the screen or sieve.
Clays should, if possible, be delivered into the brick-yard in their
moist natural state; for when they have been permitted to dry up
under a scorching sun or drying wind, they shrink and harden greatly,
and the labour of mixing into good brick " stuff " is greater, and the
plastic mixture not as free and nice as before.
Whether a natural clay contains much or little sand naturally is
not important. Every clay requires more or less grinding and mixing; and when sand in a separate form is at hand, it is easiest and
best mixed in such proportions as we may require in the pugmill. Clays naturally very rich in lime or in the alkalies (derived
from felspar) are the worst, and in fact a clay that contains more
than about 5 per cent, of lime, at the utmost, is scarcely fitted for
good brickmaking.
If the lime be in the state of carbonate, it is so much the worse;
and if it exist in the state of diffused limestone or chalk-pebbles,
it is worst of all; for these burn into caustic lime in the brick-kiln,
and then as in after-time the brick absorbs moisture and carbonic acid,
the contained nodules of lime "slack," and swell in their places,
and so burst the brick to pieces. This is one of the most prevalent
evils of the ill-made bricks which are almost universal in Ireland,
arising from the wide diffusion of limestone gravel in that country,
and the total neglect of grinding or efficient sifting of the clay.
Iron pyrites also is a not uncommon accidental product present in
clays, and unless separated, durable, to say nothing of well-coloured,
brick can never be made of the clay. The pyrites in the kiln is but
partially decomposed: oxide of iron and basic sulphides of iron
remain. When at an after-period these are exposed to air and moisture,
which are absorbed to all depths in brick, oxidation takes place,
sulphate of iron, and frequently also sulphates of lime or alums
(sulphates with double bases), are formed, and crystallising within the
mass of the brick, split it to pieces.
Common salt is nearly always present in minute quantity in clays;
but when these are taken from the sea-shore, or without or beneath the
sea-washes, or from localities in and about the salt-formations (trias),
they frequently, though in all other respects excellent clays, are
unfit for burning into good brick. Chloride of sodium is not only a

APPENDIX.

267

powerful flux when mixed even in very small proportion in clays, but
possesses the property of being volatilized by the heat of the brickkiln, and in that condition it carries with it, in a volatile state,
various metallic compounds, as those of iron, which exist in nearly all
clays, and also act as fluxes. The result is that bricks made of such
clays tend to fuse, to warp, twist, and agglutinate together upon the
surfaces long before they have been exposed to a sufficient or sufficiently prolonged heat to burn them to the core into good hard brick.
"Place bricks " can be made of such clay, but nothing more; and these are
always bad, because never afterwards free from hygrometric moisture.
Much carbonaceous matter naturally mixed in clays is also in
certain states objectionable, for when not burnt completely and in the
kiln, which is sometimes with the denser clays difficult, the bricks
are of a different colour in the interior and exterior, and will not bear
cutting for face-work, without spoiling the appearance of the brickwork. But, worse than this, such bricks when wetted in the wall
occasionally pass out soluble compounds like those absorbed from
soot by the bricks of the flue, and, like those (when used again in new
work), discolour plastering or stucco-work.
The normal constituents of brick clays, then, may be said to be
oxides of the earthy metals, and of a few others, hydrated or not,
with silicic acid, and with small amounts of the alkalies, potash and
soda, also present, together with several other chemical elements
occasionally, but uncertainly, present in minute proportions, with which
We need not concern ourselves. Silicic acid, the great electro-negative element of clays, when combined with the oxides of the earthy
bases, singly or in combination, and exposed to high temperatures
in certain proportions, forms glass or enamel (i.e., opaque glasses).
Alumina, though in a less degree, also plays the part of acid towards
the earthy bases, though itself a base with respect to silicic acid.
As regards the oxides of the earthy metals, alumina, lime, magnesia,
&c, these, in accordance with the general law of chemistry, that
bodies in the same range combine, oxides with oxides, &c, also
combine at high temperatures. The most powerful bases, such as
the alkalies or oxides of potassium and of sodium, and the oxides of
iron^ combine more readily with silicic acid than do the earthy oxides.
These combinations usually take the form of glass at once, the chief
characteristic of which is the vitreous fracture. When such glasses
are formed with oxides of earthy bases also present, they may assume
crystalline or porcellaneous textures when cooled.

268

APPENDIX.

Porcelain, earthenware, and hard brick (such as the Staffordshire
or Flintshire blue bricks) consist in substance of such compound
glasses, diffused throughout their substance uniformly, and binding
together thefinely-diffusedparticles of the excess of earthy oxides
which are present, or binding together fragmentary bits of uniformlydisused silicic acid (sand, ground flint, &c). The degree of fusibility, or of partial fusibility (agglutination), of any hard-baked brick
depends, then, not only upon the chemical nature of the constituents
of. the clay, but upon the proportions in which these are present.
The laws, so far as they have been ascertained, upon which depends
the induration or agglutination by heat of silicic and earthy compounds,
with or without other metallic oxides present, have been elicited
from innumerable experiments made by ceramic chemists upon very
varied compounds. The phenomena are complex, and in great part
as yet in results only empirical. We must refer for these to the
works of Kirwan (" Mineralogy "), who made very many experiments
upon known combinations of earths when exposed to heat—which
have not in England attracted the attention they deserved—of Achard,
Erongniart, Berthier, Lampadius, and various systematic chemical
writers. Silica, alumina, lime, magnesia, are all infusible, per se, at
the highest temperature of the porcelain furnace or brick-kiln.
Silicic acid combined with any one earth is less fusible than when
combined with two or more—a proof that not only the silicic acid
combines with each earth, but that these in its presence combine
with each other. Binary compounds of silicic acid and of earths, or
of earths with earths, are most usually infusible except at still higher
temperatures. Compounds of silicic acid with alumina are less
fusible than with lime, and these less so than with the alkalies.
With oxides of iron, silicic acid forms fusible compounds in certain
proportions. Magnesia, present in large proportions with either of
the other earths, produces a very difficultly-fusible compound.
Where the silicic acid constitutes the largest proportion of the mass,
it is much more fusible, the bases being two others combined, with or
without alkalies; but if the silicic be in great excess (as in Dinas
flre-brick), or if one or other of the earthy bases be in great excess,
more especially alumina or magnesia, the mass is infusible in the
kiln.
All difficultly-fusible and pulverulent oxides, as when obtained by
precipitation or by levigation, when exposed for some time to a high
temperature, become hard in grain, i.e., indurated more or less, and

APPENDIX.

269

frequently compacted. This is true even of some pure earths, such
as alumina and magnesia, and of nearly all the oxides of the common metals. Compound oxides, when so exposed to heat, become
still more indurated and compact, though presenting no traces of
agglutination or of fusion. Thus alumina and sesquioxide of iron
become compact. This induration, which is probably rather a change
in the state of molecular aggregation than a chemical combination,
but which may be both, is much concerned in the production of
certain qualities of brick; for example, the fine, soft, scarlet cutting
brick—that which was so much employed for fine facing-brick in the
reign of William III., down to George II.—presents no sign of
agglutination; its constituents have merely become partially indurated
and compacted by the fire. The same is true of many of the lightcoloured bricks now in use.
Two sets of forces, then, are, or may be, in play in the burning
of brick—chemical, and physical or molecular—and must be held
in view by the scientific brickmaker. To the latter belongs the contraction that takes place in the process of firing of all porcelain and
brick. This is greatest with those which contain most alumina, and
with any given specimen, is great not only in proportion to the elevation of: the temperature to which it is exposed, but with the duration
of the time of exposure. It is least in compounds in which the silicic
acid predominates; and if these pass partially from the crystalline to
the vitreous state of aggregation in the firing, the specific gravity i s
reduced, and the increase of volume may more than equal the contraction. This is said to be the case with Dinas fire-brick, which, when
highly heated in furnaces built of it, is said to expand.
Were brick constituted of silicic acid and pure clays only, it would
be perfectly white. Bricks, like porcelain, owe their colour to admixed
metallic oxides—iron in various states of oxidation, from protoxide to sesquioxide, or true chemical combinations of those with
each other, or with the earths themselves, and present in the most
varied proportions, give the whole range of colouring to bricks, from
the lightest tawny yellow, through full yellow, orange, and to the
rich scarlet of red facing-brick, almost as bright as red-lead. Where
the proportion of oxide of iron present is very large, and it combines with silicic acid to form silicates of iron in or on the brick,
its colour may be dark purple or nearly black, as is the Staffordshire
blue brick; and when a small quantity of oxide of manganese is
present also, the colour is still darkened, and may become quite black.

'

N3

270

APPENDIX.

For light-coloured bricks the clays must be almost free from iron,
and the latter must not be peroxidised, if possible, in the burning.
For the production of fine red brick, on the contrary, the clays
must be pure, silicic acid not present in excess, oxide of iron
present in abundant proportion, and be fully peroxidised, but must
not be fused into a silicate of peroxide of iron, which is fatal then
both to the texture and colour.
With a given constitution of brick clay, the final colour of the
burnt brick depends upon a large number of conditions in the process of firing, but mainly upon two—viz., what proportion of air be
admitted to the combustion of the fuel in the kiln—i.e., whether the
brick befinallyburnt with an oxidising or a deoxidising flame; and
whether or not, or in what proportion, steam or water be present in
the brick, or be brought in the state of vapour in contact with it,
when at elevated temperatures.
Upon an exact knowledge of the effects producible by the play
of these conditions (chiefly) upon the brick in burning rests the
power of the brickmaker to vary or maintain with certainty the good
colour of his ware, or to effect any desirable changes of colour of
which his material may be susceptible.
From this very incomplete sketch it will be seen that brickmaking
is one of the chemico-mechanical arts. Being so, we need scarcely
say that the foundation of all accurate and predictive knowledge of it
must be based upon a sound knowledge of chemistry, and of the laws
of physics, and of heat especially, which is but a branch of the latter.

NOTES.
COLOURED BRICKS.

Quite a new branch of trade remains to be opened in the manufacture of coloured and intaglio bricks, so treated upon the one faceside only, for both external and internal decorative building.
What may be done in this way may be seen in the Romanesque
domes of the interior covering of the great centre hall of the
museum building of Trinity College, Dublin, erected, a few years
since, by Messrs. Deane and Woodward, architects, in which ordinary
bricks are enamelled in brilliant glazed colours, arranged in designs,
upon the exposed face only.
The German architects are generally in advance of us in the art

271

APPENDIX.

of ornamental polychrome brickwork, avoiding those hideous discords
of colour that so offend the eye in many of our London buildings.
See especially for this "Les Constructions en Briques, par Louis
Degen, Ingenieur de la Commission Speciale d'Architecture de la
Ville de Munich," published in 1865, at Paris. It is marvellous
how much beauty the German brick architects contrive to extract
out of the judiciously-arranged patterns producible from mere common
brick, combined with delicate and beautiful harmonies of tint and
colour.
INFUSORIAL SILICEOUS MATERIALS, p. 22.

The bricks with which the arching of tne floor of the Museum at
Berlin was built, were made from this infusorial siliceous and microscopically porous material, mixed with a certain proportion of clay
" slip." Many of the floor arches of the Pinnacotheca, however,
were constructed of hollow bricks, in the form of frustra of cones,
like flower-pots without bottoms, laid into place with plaster or
cement.
Materials exist in Southern Italy in abundance, as also in many
other places, from which brick of considerable strength and of great
lightness might be readily and cheaply made, viz., either from certain
varieties of volcanic tufa or from pumice-stone detritus. Of the
former there are suitable beds close to Naples, and elsewhere; of the
latter, inexhaustible supplies exist in the islands of Lipari, Ischia,
and the Ponza Isles, from which it might be brought with facility.
PLASTICITY AND ODOUR OE CLAY, p.

210.

It is certainly not a general fact that no chemically pure precipitates are characterised by plasticity.
Precipitated carbonate of
lime and white-lead are instances to the contrary; but nearly all
precipitates (especially when rapidly made), though to the eye
amorphous, are in fact crystalline, as Stokes long ago proved microscopically {Dublin Phil. Mag.); and crystallised bodies are often
not plastic.
WATER CHEMICALLY COMBINED OR MECHANICALLY PRESENT, p. 212.

Water mechanically present is one thing, but water chemically
combined is another. Hydrate of alumina, in which the water plays
the part of base, is a different body chemically from the alumina
dehydrated and separated from its base by heat. The former may

272

APPENDIX.

possess plasticity, the latter not, simply because the former has the
power to retain, intimately diffused throughout its divided mass,
water in mechanical mixture while the latter has not. This diffused
water seems to be the real cause of the plasticity of clay and of all
plastic precipitates; the minute, solid, and rigid particles slip over
each other, as it were upon liquid rollers, just as two plates of glass
or metal slip over each other when afilmof water is interposed.

INDEX.
Ainslie's tile machine, 109.
Alumina, use of, in brick-earth, 14.
Blue bricks, 21.
Breeze described, 19 n.; use of, by
London brickmakers, 122; quantity required for 100,000 bricks,
153.
Brick buildings, list of early, 4.
Brick earth, composition of, 14; preparation of, 12.
Brick-kilns, Dutch, described, 48.
Brick-kilns, Hoffmann's, described,
237—244.
Brickmaking, introduction into England by the Komans, 4 ; perfection
of, in time of Henry VIII., 4 ; the
science of, 262—270.
Brickmaking machines described,
Oates's, 197; Whitehead's, 216;
Clayton's, 219; dry-clay machines
—Bradley and Craven's, 230;
Wilson's, 232.
Brick-mould described, 28.
Brick-pressing machines described—
Longley's, 223; Whitehead's, 226;
Bradley and Craven's, 227; Hersey and Walsh's, 228.
Bricks, coloured, 21, 270.
Bricks, first use of, 1 ; early use of,
by the Dutch, 3 ; application of,
by the Dutch, 4 7 ; Koman use of,
3 ; repeal of the duties dn, 8;
schedule of duties on, 7; strength
of bricks, 9 ; comparison of the
strength of hand and machinemade bricks, 1 1 ; used as a building material after the fire of London, 5.
Bricks, manufacture of, 12; various
modes of manufacturing, described,
9 ; colour of, 2 0 ; influence of the
chemical composition of clay on

the colour of bricks, 20; variation
in the weight of, 10; drying, 2 5 1 ;
usual form of, 34; warping of, 33;
weekly produce of a London yard,
3 7 ; annual manufacture of, in
Great Britain, 8.
Bricks, manufacture of, by machinery, 195; list of patents for, 196;
machines described, 197; strength
of machine-made bricks, 203.
Bricks, Egyptian, 2 ; two classes of,
19; with hollow beds, 3 4 ; for
railway work, 26.
Burning, process of, 38.
Chalk, use of, in brickmaking, 18,
121.
Cheshunt, brickmaMng at, 157.
Clamp-burning described, 38.
Clay, analysis of, 12,115, 265; composition of, 1 3 ; properties of, 245;
cannot be produced artificially,
2 4 6 ; its plasticity, 248—271;
odour of, 250; digging, 22; process of preparing, 2 4 ; tables of
colour, order of fusibility, &c,
Clay, dry, machines for working, 230.
Clay, machines for preparing, 212—
215; clay crushing and grinding
mill, 212; pug-mill, 27, 2 1 3 ; perforated pug-mill, 214; portable
clay-mill, 215; composite machines
for crushing and tempering, 215.
Clayton's horizontal brick machine,
219.
Coal, anatysis of, 117.
Goal-dust, use of, for making clamp
bricks, 251.
Compound for brick-earth, 14.
Copper moulds, method of using, 30.
Cupola, 40.
Cutters, 19.

274

INDEX.

Dense bricks, disadvantages of, 32.
Dinas fire-bricks, 16; manufacture
of, 16.
Drain-pipes, machine f o r t h e manufacture of, 205; manufacture of,
by machinery, 195.
Drain-tiles, manufacture of, 4 3 ;
making and burning, 255; cost of,
261; machine for making, 256;
cost of, 256; sheds for drying, 257;
working the clay, 221.
Drying, process of, described", 35.
Dutch, their early use of bricks, 3.
Dutch bricks, size of, 48.
Dutch method of burning bricks
described, 50.
Dutch tile kilns described, 53 ; me*
thod of filling the kilns, 53, 49 ;
fuel used for, 43.
Dutch tiles, method of making, 52;
mode of glazing, 54; mode of
burning, 53.
Encaustic tiles, manufacture of,
189; colours, production of, 191;
colouring the tiles, 192; glazing,
193; moulding, 192; plain tiles,
193 ; slip described, 192.
Fire-bricks, 15; value of, 18.
Fire clays, composition of, 15 • where
found, 17.
Floating bricks, 21.
Fuel for brickburning, 41.
Fusible earths, 19.
Grinding described, 23.
Holland, manufacture of bricks and
tiles in, 47.
Hollow bricks, form of, 207 ; method
of using, illustrated, 209; machine
made, 207; Roman use of, 207;
use of, in Tunis, 207.
Kiln described, 3 8 ; circular, 40;
burning described, 39, 40.
Lincolnshire, brickmaking in, 252;
cost of production, 252.
Loams, 14.
London-made bricks, superiority of,
19.
London, brickmaking in, 119; process, 138; cost, 159; arrangement
of a brickwork, 123 ; cost of materials, 159; breeze, 155; cost of
breeze, 159; brick-earth, 119;

cost of chalk, 159; chalk mill,
164; clamp described, 144; clampr
ing, 144; foundations of the clamp,
149; upright of ditto, 150; paving,
154; necks, 152; clay described,
120 ; cost of the clay, 159 ; digging
the clay, 138; quantity of clay
required for 1,000 bricks, 139; claywashing mill, 165; use of chuckhold, 125; process of firing, 152;
cost of fuel, 159; hacking described, 142; hack barrow, 136 ;
hack ground, 136; cost of labour,
162; costof machinery, 161; process of maiming, 139 ; malm, 120;
hand method of preparing malm,
120 ; chalkmilldeseribed,123,164 ;
clay mill, 123 ; brick mould, 135;
moulding, 141; moulding-stool,
125 ; pallets, 136 ; pug-mill, 123;
pugging, 141; cost of sand, 159 ;
scintles, 154 ; scintling, 143, 149;
process of soiling, 140; use of soil,
122; cost of Boil, 159 ; use of stockboard, 135; use of the strike, 136 ;
tempering described, 141; cost of
tools, 161; cost of water, 159;
cost of wood, 159; illusti ationa of
London brickmaking, 164.
London brickmaking: bats, 156 ;
place bricks, 156; burnovers, 153;
burrs, 156 ; clinkers, 153 ; cutters,
155 ; grizzeles, 156 ; malms, 155;
paviours, 156; pickings, 156;
seconds, 156; shuffs, 156; grey
stocks, 156 ; rough stocks, 156.
London tile making described, 167;
block board described, 175; buildings, 170 ; clay getting, 183; kiln,
183; kilning, 186; illustrations
to, described, 186; moulding, 184;
moulding-shed, 173; pantile table,
174; place grounds, 187; plant,
170; roll described, 177; sling,
description of, 170 ; slinging, 184;
splayer, 180; tempering, 184;
thwacker, 183; thwacking, 185;
thwacking frame, 180; thwacking
knife, 183; thwacking stool, 183 ;
washing-off frame, 178; washing-off table, 177; weathering,
183.
Marls, 14.
Minton's encaustic tile manufactory
described, 191.
Moulding, process of, 28
Moulding table, 29.

INDEX.
Norton coal, analysis of, 117.
Nottingham, brickmaking at, 55;
process of, 80 ; illustrations of,
described, 92 ; batting, 8 2 ; cost of
buildings, 88; burning described,
84; colour, 58; brick-earth, 57;
cost of ditto, 87 ; brick-moulds,
70 ; bricks, number made per day,
84; size of bricks, 84; brick-yaid,
general arrangements, 59; clapper
described, 7 3 ; clay digging, 80;
clay mill described, 62 ; dressingbench, 7 3 ; dressing described,
82; drying process, 81 ; flats
described, 7 1 ; fuel for the kilns,
88; hovel described, 61, 72; kiln,
7 5 ; setting the kiln, 84; cost
of setting and drawing kiln, 8 6 ;
cost of labour, 90; cost of land,
87; machinery for pressing bricks,
74; cost of machinery, 8 8 ; cost
of manufacture, 87; moulding described, 8 0 ; moulding sand, C&;
moulding table, 68; plane described, 7 1 ; polished bricks, 83 ;
pressed bricks, 8 3 ; tempering described, 67, 80; cost of tools, 90 ;
wash milL described, 66.
Oates's brickmaking machines, 196;
cost of, 204; rate of production,
204.
Ornamental brickwork, examples of,
Pallet moulding described, 29.
Paving tiles, 42.
Pressed bricks, defects of, 33.
Prosser's method of making bricks,
32.
Pug-mill described, 27.
Red bricks, 21.
Refractory clays, composition of, 15.
Roofing tiles, 42.
Sand, object of using, 122.
Silica, use of, in brickmaking, 14.
Slip kiln, 32 n.
Slop moulding described, 28.
Soil, term described, 27 n.
Staffordshire brickmaking described,
95, 9 7 ; buildings described, 97;
burning, 99; clay, described, 95;
cost of manufacture, 101; drying,
9 9 ; firing, 109; illustrations,
102 ; moulding, 98, 103; oven

275

described, 100; plant described,
97 ; rate of production, 97; rental,
101; specific gravity of the bricks,
when raw, dried, and burned,
99; tempering, 9 7 ; weight of the
bricks, 99; arrangements of yard,
118.
Staffordshire tile making, 105; class
of tiles made, 9 5 ; drain tiles,
108; d n i n g , 107; manner of
drying, 111; firing, 113; illustrations to, described, 111; machines
for making, 108; moulding, 107;
moulding bench described, 1 1 1 ;
pug-mill described, 106; setting
described, 108; tempering, 106 ;
weathering, 106.
Stourbridge clay, 151.
Striking the clay,, 28.
Suffolk, brickmaking in, 252; burning, 253; clay, 263 ; drying, 253;
cost of manufacture, 254; moulding, 253; cost of plant, 254 ; tempering, 253.
Table of analysis of different kinds
of clay, 13 w.; of analysia of
Norton coal, 117; of analysis of
Staffordshire clays, 115; of the
colour of Staffordshire clays, 116 ;
of the cost of 1,000 bricks, London
make, 162; of the cost of Londonmade pantiles per 1,000, 187; of
the cost and profit on 1,000 Nottingham-made bricks, 9 1 ; of the
cost and selling price of Stafford
quarries, dust bricks, and roof
tiles, 111; of the fusibility of
Staffordshire clays, 116; of the
price of fire-bricks of various
manufactures, 18; showing the
proportion of bases contained in
Staffordshire cla)s, 116; of the
relative value of different qualities
of bricks Nottingham make, 9 1 ;
of the selling price of Londonmade tiles, 187 ; of space required
for each moulding-stool by either
process, 37; of loss of weight in
drying and burning, 99; of the
strength of hand and machinemade bricks, 11.
Taxes upon bricks, 6 ; repeal of the,
8.
Tempering, 2 5 ; process described,
27.
Terra-cotta, early use of, 5.
Tesserse, Minton's, 193; Roman

276

INDEX.

process described, 193; modern
process described, 194.
Tile-burning, 44, 255.
Tile-kilns, construction of, 183,189,
257 ; in Holland, 63.
Tile-making in England, 4 2 ; in
Holland, 5 2 ; in Staffordshire,
105; in London, 167.
Tile-making machines, Ainslie's, 109;
Hatcher's, 256; Page's, 233; Whitehead^ 234.
Tile-moulding, 184.
Tileries, London, 167; Staffordshire,
105.
Tiles, encaustic, manufacture of, 189.
Tiles, manufacture of, 4 2 ; schedule
of duties on, 7 ; cost of manufacture, 186; manufacture of, in
Holland, 52.
Tower of Babel, burnt bricks used in
building, 1.

Unsoiling, 22.
Utrecht, principal seat of tile manufacture in Holland, 54.
Ventilating bricks, 35.
Washing described, 24.
Weathering, process of, 22.
White bricks, 21.
Whitehead's brickmaking machine,
216 ; brick-pressing machine, 226 ;
clay crushing and grinding mill,
212; perforated pug-mill, 214;
tile-making machine, 234.
Wilson's dry-clay brick machine,
232.
Wooden moulds, method of using,
30.
Yellow bricks, 21.

T H E END.

VIRTUE AND CO., PRINTERS, CITY ROAD, LONDON