[Illustration: KILN FOR BURNING CHARCOAL.]
In answer to the inquiry of a correspondent about charcoal making, we
offer two illustrations that show a method of manufacture differing from
that usually adopted, which is that of burning on the bare ground, and
covering with soil or sods to exclude the air. These kilns are made of
brick, one course being sufficient, bands of iron or timber framework
being added to strengthen the brickwork with greater economy. The usual
style is conical, and the size is 24 feet in diameter, with an equal
height, holding about 40 cords of wood. The difference in price is 1-1/8
d. per bushel in favor of these kilns as compared with the usual mounds,
the burner being furnished with the use of the kilns, and the timber
standing, the kiln burning costing 2-1/8 d., and the other 3-1/4 d. The
kilns must be lined to about halfway up with fire-brick, the cost of which
will vary with the locality, but will be about £200, and as 40 to 50
bushels of coal have been made per cord the extra yield on good charcoal
and the lessening of the cost of making soon covers any extra outlay on
the cost of the kilns. The wall of the kiln is carried up nearly straight
for 6 feet, when it is drawn in, so as to become bluntly conical. Upon the
top a plate of iron is fastened in the manner of the keystone of an arch,
and bands of iron are passed round the kiln and drawn tight with screw
bolts and nuts to strengthen it. Double doors of sheet-iron are made at
the bottom and near the tops, by which it is either filled or emptied, and
a few air-holes (B), which may be stopped with loose bricks, left in the
bottom. The second figure shows a kiln of another shape made to burn 3,000
bushels of charcoal, or about 80 cords of wood. The shape is a
parallelogram, having an arched roof, and it is strengthened by a
framework of timber 10 inches square. As the pressure of the gas is
sometimes very great, the walls must be built a brick and a half thick to
prevent their bursting. The usual size is 16 feet wide and high, and 40
feet in length, outside measure. The time occupied in filling, burning,
and emptying a small cone is about three weeks, and four weeks is required
for the larger ones.--_The Gardeners' Chronicle._
[Illustration: KILN FOR BURNING CHARCOAL.]
* * * * *