700 



CHARCOAL 



altogether at any steep angle, sloping outwards from tho centre to form a flattened 

 cone, "which when complete is usually called a heap ; tho object, whichever way the 

 wood is placed, is to obtain a free circulation of air under the heap, to communicate 

 with the chimney in the centre, -which is formed by then withdrawing the central 

 pole or bundle of brushwood. The large wood should if convenient bo at tho bottom 

 of tho heap, and the outside packed as close as possible ; the heap is then covered 

 with small brushwood, and afterwards with turf, or the material most impervious to 

 air which can be conveniently obtained. A fire is lighted in the centre chimney, and 

 by leaving openings in the outside-covering at the bottom of the heap, the fire 

 soon extends, and can be guided to any part by making temporary openings to 

 admit the air. When the heap is sufficiently fired all tho> openings are closed, and 

 lastly the chimney itself. The fire will always extend most rapidly -on the side facing 

 or towards the -wind; and great care must be taken to watch and check this, by 

 keeping the covering on that side in good order. The charcoal burner must always 

 be careful to spread the fire as evenly as possible through the heap, and after it is 

 coaled to stop it down carefully ; he can always accelerate the process in any part 

 of the heap if well built> by opening tho outside to admit air freely : but if he finds 

 this does not act, from any fault in setting the wood, ho had better open a hole with 

 a bar at the place required, and light a fire in the hole ; this will soon communicate 

 with the main fire in the heap. As soon as the smoke and white flame cease to 

 escape at the vents, the whole heap must be closed from the air as carefully as 

 possible, until the charcoal is quite cooled and is ready to draw. The fire must 

 never burn too fast ; the slower the process, if the fire is steady and regular, the 

 better the yield of charcoal. Hard close-grained woods take a longer time to coal 

 than soft open-grained woods, and should be placed in the heap accordingly. These 

 technical instructions, handed down in the forests for ages as secrets from father to 

 son amongst the ' coalliers ' in every country in Europe, are the results of long 

 practical experience, and strictly accord with the true principles on which the 

 process is based. 



To carbonise wood under a moveable covering, the plan of Meiler, or heaps, is em- 

 ployed very much in Germany. The -wood is arranged either in horizontal layers, 

 or in nearly vertical ones, with a slight slope, so as to form conical rounded heaps of 

 different sizes. The former are called ' lying Meiler,' Jig. 442 ; tho latter ' standing 

 Meiler,' figs. 443 and 444. Both are distributed in much the same way. 



442 



443 



444 



In districts where the wood can be transported into one place by means of rivers, 

 or mountain slides, a dry flat space must be pitched upon, screened from storms and 

 floods, which may be walled round, having a slight declivity made in the ground, 

 towards the centre. (See fig. 445.) Into this space the tarry acid will partially fall, 



and may be conducted outwards, 



445 through a covered gutter beneath, 



into a covered tank. The mouth 

 of the tank must be shut, during 

 the coking, with an iron or stone 

 slab, luted with clay. A square 

 iron plate is placed over the inner 

 orifice or the gutter to prevent it 

 being choked with coal ashes. Fig. 445 represents a walled Meiler station: a, the 

 station ; b, tho gutter ; c, the tank, which is covered with the slab d ; e, a slab which 

 serves to keep the gutter clear of coals. The cover of the heaps is formed of earth, 

 sand, ashes, or such other matter as may be most readily found in the woods. They 

 should be kindled in the centre. From 6 days to 4 weeks may be required fot 

 charring a heap, according to its size, hard wood requiring most time ; and the slower 

 the process, the better and greater is the product, generally speaking. 



Charring of wood in mounds (Haufe or liegende Werke], figs. 446 and 447, differs 

 from that in the Meiler, because the wood in the Haufe is successively charred, and the 



