COKE MANUFACTURE. i 563 | 
quired 54 piles of the dimensions given, occupying a good 300x250 ft., 
and the labor of 23 men. 
At Hollidaysburgh, Pa., coke was formerly made in heaps about 12 
feet wide at the base, and 2 ft. 8 in. in height, requiring 5 days to burn, 
and yielding with bituminous coal about 40 per cent. of coke. 
Coke piles are sometimes made with the flues running across the 
width of the pile, at intervals of 3 or 4 feet. The flues may be built of 
large coal, or if this is not at hand, frames of wood like, troughs, having 
the dimensions of the flue, are placed in the desired position and the 
intervals packed lightly with wetted coal, after which the frames are 
removed, being a well defined flue. ‘The piles are finished as already 
described, but they are lighted by vertical chimneys, formed by a stick 
stuck in the center of the transverse flues while the pile was building, 
and which are afterwards drawn out, leaving a vertical chimney, down 
which lighted coals are dropped. 
In England it is the custom when burning in rectangular piles, 
to construct a longitudinal flue, and in the length of the pile to 
make vertical chimneys from the flue, by placing stakes at inter- 
vals of 10 feet, which are afterwards withdrawn. By these chim- 
neys burning coals may be introduced, and the fire communicated 
to the center and at many points of the pile at once. The operation is 
conducted as already described, and when the workman sees that the 
fire has reached the exterior of the heap at any point, it is immediately 
quenched by coal breeze. By this construction of pile, they may be 
made of great size, 100 to 200 feet in length, containing sometimes over 
2,000 tons of coal. Their width is usually not greater than 12 feet, 
and when the coal is particularly impure, they are made somewhat nar- 
rower. By lighting them at one end first, the operation may be made 
continuous for some time, the pile being built at one end, while the coke 
is removed from the other as fast as it is coked. In burning a heap, it 
is essential to get the fire to the center as quickly as possible, and then 
draw it outward toward the surface, as is done in charring wood. 
The production of coke in piles will of course vary greatly with 
the character of the coal, but usually they may be taken to produce 
from 30 to 50 per cent. 
M. Jordan* describes a method formerly employed in the coal 
* Album du cour du Metallurgie. . 
