ly driven into the ground, so
as to stand vertically and equi-distant from each other, leaving within
them a space of six or eight inches. Around these poles the peats are
placed endwise, in concentric rows to the required width and height,
leaving at the bottom a number of air-channels of the width of one peat,
radiating from the centre outwards. The upper layers of peat are
narrowed in so as to round off the heap, which is first covered with dry
leaves, sods, or moss, over which a layer of soil is thrown. Dry, light
wood being placed at the bottom of the central shaft, it is kindled from
one of the canals at the bottom, and the charring is conducted as is
usual in making wood coal. The yield of coal ranges from 25 to 35 _per
cent._ of the peat by weight, and from 30 to 50 _per cent._ by volume.

Gysser recommends to mould the peat for charring in the form of
cylinders of 3 to 4 feet long, which, when dry, may be built up into a
heap like wood.

A great variety of ovens or kilns have been constructed for coking peat.

At the Gun Factory of Oberndorf, in Wirtemberg, peat is charred in the
kiln represented in the accompanying figure. The chamber is 9 feet high,
and 5-1/2 feet in diameter. The oven proper, _b b_, is surrounded by a
mantle of brick _a a_, and the space between, _c c_, is filled with
sand. Each wall, as well as the space, is 15 inches in thickness, and
the walls are connected by stones _d d_, at intervals of three feet.
Above the sole of the kiln, are three series of air holes, made by
imbedding old gun barrels in the walls. The door, which serves to empty
the kiln, is a plate of cast iron, the sides of its frame are wider than
the thickness of the wall, and by means of a board _e_, a box _m_ can be
made in front of the door, which is filled with sand to prevent access
of air. The peat is filled in through _i_, a channel being arranged
across the bottom of the kiln, from the door _f_, for kindling. When the
firing begins, the lowest air-holes and _i_ are open. When, through the
lower gun barrels, the peat is seen to be ignited, these are corked, and
those above are opened. When the smoke ceases to escape above, all the
openings are closed, _m_, is filled with sand, _i_ is covered over with
it, and the whole is left to cool. It requires about 8 to 9 days to
finish the charring of a charge. Several kilns are kept in operation, so
that the work proceeds uninterruptedly.

[Illustration: Fig. 23.--OBERNDORFER