546 AUXILIARY FOREST INDUSTRIES. 



removing part of the roof and putting earth on it, the walls 

 not being opened. 



(vi) The charcoal is removed first from the front of the 

 kiln. A portion is removed daily, and the kiln closed again. 



In Steiermark, a commencement is made by removing the 

 charcoal whilst the back of the kiln is still burning. As the 

 front part of the kiln burns longest and the charcoal there 

 becomes light, attempts are made to prevent this by its early 

 removal. It should, however, be remembered that this frequent 

 opening increases the draught, and must cause a considerable 

 loss of charcoal. 



3. Pit-kilns. 



Charcoal-making in pits is the roughest and least productive 

 method. A round pit with sloping sides is dug in ground 

 sufficiently firm for the purpose, to a depth of about a meter, 

 and is filled with dry brushwood. This is kindled and remains 

 burning openly until the smoke ceases and the glowing embers 

 remain ; these are then pressed together, the wood being 

 placed in the pit and left to burn till the smoke has ceased. 

 Fresh wood is then thrown in at repeated intervals until the 

 pit is full. Then the pit is covered with sods and earth, and 

 the charcoal allowed time to cool ; the pit can be opened in 

 1 to 2 days for removal of the charcoal. Such a method is 

 justifiable only when wood has hardly any value, as almost free 

 admission of air is involved. If the pit is dug on a little hill 

 or on a gentle mountain-slope so that a channel from it leads 

 out to the lowest part of the ground, the liquid products of 

 distillation (tar) can be secured. Similarly tar may be col- 

 lected from ordinary kilns if pits are dug below the kiln, as in 

 Kussia. Kilns may be surrounded also by masonry, as in 

 lime-kilns, so that both charcoal and tar may be obtained. 



4. Yield of Charcoal 



In discussing the quantity of charcoal which a certain volume 

 of wood may be made to yield, the following points should be 

 considered : the kind of wood, situation of kiln, state of 

 weather, process and duration of burning, and different 

 methods of carbonisation. 



