THE TECHNOLOGIST. [Skit. 1, 1665. 
72 THE MANUFACTURE OF COMPRESSED PEAT. 
extent of the bog at present operated on, the author next detailed the 
apparatus in use at the works. They consist of a railway formed of 
thirty-six-pound rails, well fished at the joints, riming along the centre 
of the drained piece of bog. It is laid on sleepers of native timber, and 
carries an eight-ton locomotive. On these rails runs a six-wheeled truck, 
across which, and reaching the entire width of the drained ground, lies 
a square box lattice girder, which is formed of half -inch angle iron at 
the corners, latticed on each of the four sides by one and a half inch by 
one-quarter inch iron, with two feet spaces. It is six feet square at the 
centre, where it rests on the waggon, and tapers to one foot square at each 
end, and is assisted perpendicularly and laterally by wire rope stays, set in 
taut. This apparatus is propelled by the locomotive at the rate of four 
miles an hour, with its great arms stretching over the bog at each side to 
the distance of nearly one hundred and fifty feet, and to it are attached ten 
harrows, each six feet square, which by repeatedly passing over the ground 
scarify the surface to a depth of from one to two inches. This operation 
is performed during any moderately fine weather, and in the mornings 
and during the day the light powdered surface, which readily dries to a 
certain extent, is wheeled to the road by men, and waggoned into the 
works for manufacture. In dry weather the upper surface of the bog, 
thoroughly drained as it is, will always contain much less water, perhaps 
less than half what the general mass retains ; and as by this mode of 
operation a fresh upper" surface is being daily exposed, it follows that 
peat in the most favourable state for drying is being constantly operated 
on. As soon as the harrowing begins rapid and continuous drying 
takes place, and a very large portion of the water which is not removed 
by drainage is evaporated by a few hours' exposure. The mull when 
waggoned into the factory is generally found to consist of about forty 
per cent, peat, and sixty per cent, water. Bog in its natural 
state consists of ninety parts water and ten peat. When drained 
as described, after some hours of an average dry day, it consists 
of sixty parts water and forty peat. At Deny lea, the only arti- 
ficial heat used is that obtained from the waste steam of the com- 
pressing engines and the smoke and gases of the boiler fires. These 
are applied to heat very extensive surfaces formed of sheet-iron, on 
which is spread a thin layer of peat mull, kept in continual and pro- 
gressive motion by machinery. The drying kilns consist of brick build- 
ings, five hundred feet long by thirty feet wide, having an upper and 
under floor of one-eighth inch sheet-iron, extending the entire length. 
The buildings are of brick, roofed with tiles. Under the lower floor, 
which is placed about two feet from the ground, is blown the smoke 
and waste heat of the boiler, and instead of the ordinary chimney a 
large fan is used to urge the fires, and force the products of combustion 
under this sheet-iron table. The upper floor is carried on cast-iron gir- 
ders, and stands four feet high above the lower one. It is made double, 
with a distance between the sheets, about four inches, for the purpose of 
