BRICK-MAKING. 
ble to pieces, and disclose straws, reeds, and other 
vegetable matter, from the existence of which it 
is inferred they have never been submitted to 
any greater heat than that of the sun. At a 
later period all the bricks of the ancients were 
burnt, and it is these that chiefly remain at the 
present day. 
A brick is nothing more than a mass of argil- 
laceous earth or clay, properly tempered with 
water and softened, so that it can be pressed in- 
toa mould to give it form, when it is dried in 
the sun, and afterwards submitted to such a heat 
as shall bake or burn it into a hard substance. 
This method of forming bricks puts a limit to 
their magnitude; for, as the material of the brick 
is a bad conductor of heat, so, if they were made 
very large, the heat applied externally would 
never reach the inside so as to bake it properly, 
without vitrifying and destroying the outside ; 
hence bricks must be confined to such magni- 
tudes as will admit of their being well and equa- 
bly burnt throughout. In England, the size of 
bricks is determined by law, and no man can 
make bricks larger or smaller than the prescribed 
dimensions. This law is, by many, considered a 
hardship, but it was established for a two-fold 
purpose, first, because all bricks were subject to 
an excise duty or tax of about a dollar a thou- 
sand, which tax could not be equalized, unless a 
size was fixed for the brick ; and, secondly, it 
enables a person building, to know the exact 
quantity of work he can erect for a certain sum 
of money, and prevents brickmakers taking ad- 
vantage by sending out small bricks, or making 
them so large that their insides may not be hard 
and well burnt, a circumstance that would pro- 
duce unsound work, deficient in durability. The 
standard size in London is eight and three-quar- 
ter inches long, four and three-eighths wide, and 
three and three-quarter inches thick ; the inten- 
tion of these dimensions being, that each brick 
laid end to end, or every two bricks side to side, 
with the necessary quantity of mortar between 
them, shall make exactly nine inches of work ; 
or that four bricks laid one on another, shall 
make a foot perpendicular, or twelve courses 
to the yard. Good brick, having the specific 
gravity of 2°168, requires 1,200 pounds on a square 
inch to crush it. 
BRICK-MAKING. Although clay has been 
named as the proper material for making bricks, 
yet every clay will not answer equally well. Pure 
clay is quite white, and in burning does not 
change its colour, as may be noticed in tobacco 
pipes, which are made from it. The brown col- 
our of common clay is usually derived from oxide 
of iron, and this causes the brick to assume a red 
colour when burnt; but as red bricks are not 
approved or used for outside work in London— 
where more bricks are made and consumed than 
in any other part of the world—the brickmakers 
have contrived means of changing their colour 
in burning to a pale buff very much resembling 
033 
the colour of Bath-stone, and which gives build- 
ings a much handsomer appearanée, and closer 
resemblance to stone, than would be expected. 
The mode of colouring is kept as secret as pos- 
sible among the manufacturers, but it is partly 
produced by mixing powdered chalk with the 
clay, and is, probably, greatly dependent upon 
the firing of the kiln and the fuel used, since 
many bricks that exhibit a beautiful and perfect 
buff hue on their outsides, are red and dark 
within, if broken. 
A stiff, tenacious, plastic clay is unfit for mak- 
ing bricks, as they generally split and fall to 
pieces in burning. Brickmakers call such clay 
strong earth, and they prefer what they term a 
mild earth; that is, one of less tenacity, and 
having more the character of loam. When the 
loamy soil is not found naturally, it is imitated 
by adding sand in considerable quantity to earth 
that is too strong. The London brickmakers, in 
addition to sand, constantly add a considerable 
quantity of breeze to their clay, and they assert 
that it is this material that gives the peculiar 
character of colour, hardness, and durability to 
London bricks. This is somewhat corroborated 
by the country bricks, made without breeze, be- 
ing red and of a very different character. To 
explain the term breeze, which seems to perform 
so important a part, it becomes necessary to say 
that throughout the immense metropolis London, 
no fuel is used in any of the houses but bitumin- 
ous or blazing coal. Every house has what is 
called a dust-hole, in some external part of the 
premises, into which the ashes and refuse of these 
fires are put, and the same place is also a deposi- 
tory for any other offal of the house, which must 
not be thrown into the streets. The parish- 
authorities contract with persons having horses | 
and carts to clear these dust-holes about once a- 
week or oftener, without any expense or trouble 
to the housekeeper, and the stuff collected is all 
carried to certain fixed depositories on the out- 
skirts of the town. 
women, and children, are daily employed in as- 
sorting and looking over the mountains of dis- 
earded treasure thus brought in, and now be- 
come the property of the contractor; apparently 
worthless in the eyes of the public, but not so in 
fact, for most of the men who have undertaken 
this business, in conjunction with that of scaven- 
ger or street cleaner, have in almost every in- 
stance amassed immense fortunes. The heaps of 
soil are carefully raked over, and every atom of 
them passed through several gradations of sift- 
ing, with sieves of various fineness. Rags, old 
iron, metal, bones, and such things as are usually 
thrown away, mixed with the refuse fuel, form 
the aggregate of the mass, and all these things 
are separated and placed in separate heaps. Here 
the paper-maker gets supplied with much com- 
mon rag for packing-paper. The old iron is re- 
turned to the forge to be manufactured into 
scrap iron. The hartshorn and ivory black 
—__—_. 
Here hundreds of men, || 
