d for six bricks. A plunger forces
the clay into it, the mould is emptied, and in a single hour five
thousand bricks can be made. By what is called the "stiff-mud"
process, the stiff clay is put into a machine with an opening the size
of the end or side of a brick. The machine forces the clay through
this opening, cuts it off at the proper moment; and so makes bricks by
the thousand without either mould or moulder. A third way of making
brick is by what is called the "dry process." The clay is pulverized
and filled into moulds the length and breadth of a brick, but much
deeper, and with neither top nor bottom. One plunger from above and
another from below strike the clay in the mould with much force, and
make the fine, smooth brick known as "pressed brick." All this is done
by machinery, and some machines make six bricks at a time. These
"dry" bricks are fragile before they are burned, and must be handled
with great care.

Bricks cannot be put into the kiln while they are still wet, for when
a brick is drying, it is a delicate article. It objects to being too
hot or too cold, and it will not stand showers or drafts. In some way
about a pound of water must be dried out of each brick; but if you try
to hurry the drying, the brick turns sulky, refuses to have anything
more to do with you, and proceeds to crack. To dry, bricks are
sometimes spread on floors; or piled up in racks on short pieces of
board called "pallets"; and sometimes they are put upon little cars
and run slowly through heated tunnels. The last is the best way for
people who are in a hurry, for it takes only from twenty-four to
thirty-six hours to make the bricks ready to go to the kiln to be
burned.

In one sort of kiln, the bricks themselves make the kiln. They are
piled up in arches, but left a little way apart so the hot air can
move freely among them. The sides of the structure are covered with
burnt brick and mud, but the top is left open to allow the steam from
the hot bricks to escape. The fires are in flues that are left at the
bottom. They must burn slowly at first, but after a while, some forty
to sixty hours, the heat becomes intense. Thus far the bricks have
been grayish or cream-colored, but now, if there is iron in them, they
turn red; if there is lime, they turn yellow; if a large amount of
lime, they become flesh-colored. Besides this sort of kiln, which is
torn down when the bricks are sufficiently burned, there is also the
permanent ki