PEAT CHARRING KILN.]

[Illustration: Fig. 24.--WEBER'S CHARRING FURNACE.--TRANSVERSE SECTION.]

[Illustration: Fig. 25.--WEBER'S CHARRING FURNACE.--LONGITUDINAL
SECTION.]

At Staltach, Weber prepares peat coal in a cylinder of sheet iron, which
is surrounded by masonry. Below, it rests on a grating of stout wire.
Above, it has a cover, that may be raised by a pulley and on one side is
attached a small furnace, figure 24, the draught of which is kept up by
means of a blower, or an exhauster, and the flame and hot gases from
it, _which contain no excess of oxygen_, play upon the peat and
decompose it, expelling its volatile portions without burning or wasting
it in the slightest degree. The construction of the furnace, see fig.
24, is such, that the sticks of wood, which are employed for fuel, are
supported at their ends on shoulders in the brick-work, and the draught
enters the fire above instead of below. The wood is hereby completely
consumed, and by regulating the supply of air at _a_ (fig. 25) by a
sliding cover, and at _b_ by a register, the flame and current of air
which enters the cylinder containing the peat, is intensely hot and
accomplishes a rapid carbonization of the peat, but as before stated,
does not burn it. In this furnace the wood, which is cut of uniform
length, is itself the grate, since iron would melt or rapidly burn out;
and the coals that fall are consumed by the air admitted through c. The
hot gases which enter the cylinder filled with peat near its top, are
distributed by pipes, and, passing off through the grating at the
bottom, enter the surrounding brick mantle. Before reaching the
exhaustor, however, they pass through a cooler in which a quantity of
tar and pyroligneous acid is collected.

Weber's oven is 15 feet in diameter, and 3-1/2 feet high; 528 cubic feet
of peat may be coked in it in the space of 15 hours. The wood furnace is
2 feet in section, and consumes for the above amount of peat 3-1/2 cwt.
of wood. So perfectly are the contents of the iron cylinder protected
from contact of oxygen, that a rabbit placed within it, has been
converted into coal without the singeing of a hair; and a bouquet of
flowers has been carbonized, perfectly retaining its shape. The yield of
coal in Weber's oven is nearly 50 _per cent._ of the peat by weight.

Whenever possible, charring of peat should be carried on, or aided by
waste heat, or the heat necessary to coking should be itself economized.
I