CHAECOAL 



761 



charcoal is raked out by little and little. The product is said to be greater in this 

 way, and also better. Uncleft billets, 6 or 8 feet long, being laid over each other, 

 aro covered with ashes, and then 

 carbonised. The station is some- 

 times horizontal, and sometimes 

 made to slope. The length may 

 be 24 feet, the breadth 8 feet ; and 

 the wood is laid crosswise. Piles 

 are set perpendicularly to support 

 a roof made of boughs and leaves 

 covered with ashes. Pipes are 

 occasionally laid within the upper 

 part of the mounds, which serve to 

 catch and carry off some of the 

 liquid. 



Fig. 448 is a vertical section, 

 and fig. 449 a half bird's-eye view, 

 and half cross-section at the height 

 of the pit bottom, of Chabeaus- 

 siere's kiln for making wood charcoal, a is the oven ; b, vertical air-pipes ; c c, 

 horizontal flues for admitting air to the kiln ; d d, small pits which communicate by 

 short horizontal pipes e e, with 

 the vertical ones ; /, the sole of 

 the kiln, a circle of brickwork, 

 upon which the cover or hood, h, 

 reposes ; i, a pipe which leads to 

 the cistern k ; I, the pipe destined 

 for carrying off the gaseous mat- j 

 ter ; m m, holes in lie iron cover 

 or lid. 



The distribution of the wood is 

 like that in the horizontal Metier, 

 or heaps ; it is kindled in the 

 central vertical canal with burn- 

 ing fuel, and the lid is covered 

 with a few inches of earth. At 

 the beginning of the operation all 

 the draught flues are left open, 

 but they aro progressively closed, 

 as occasion requires. In eight kilns of this kind, 500 decasters of oak wood are 

 carbonised, from which 15,000 hectolitres of charcoal are obtained, equal to 64,000 

 pounds French, being about 25 per cent., besides tar, and 3,000 velts of wood vinegar, 

 of from 2 to 3 BaumS. 



449 



At Crouy-upon-the-Ourcq, near Moaux, there is a well-constructed kiln for making 

 turf-charcoal. It resembles most nearly a tar-kiln. In fig. 450, a is the cylindrical 



