CHARCOAL-MAKING. 543 



The Alpine method then differs from the ordinary method 

 of burning kilns in the following points : 



(i) The large dimensions of the pieces of wood to he carhonised 

 and the fact that usually they are not split. 



(ii) The wooden base of the kiln to cause a draught of air, 

 which is required owing to the large pieces of usually green 

 w r ood which are being carbonised. 



(hi) The large dimensions of the kilns. 



(iv) Only one covering being applied to the kilns, that is 

 usually thick and requires special supports. 



(v) By the special mode of kindling, which is usually, though 

 not always, from above. 



2. Kilns with I rood piled Ifnri.:<iut<tUy. 



In Sweden and Austria, wood to be carbonised is piled 

 horizontally, but the practice is becoming less frequent than 

 was formerly the case. The following are the chief points of 

 difference between this and the ordinary method. 



(i) The wood carbonised is chiefly coniferous ; the pieces are 

 round logs, barked if possible, and of various dimensions up to 

 20 feet or (in Sweden) 26 feet in length. The pieces of wood 

 must be quite straight, or they could not be piled densely.' As 

 such large pieces may be used for timber, the method is 

 employed only in localities where the timber of the species in 

 question is unsaleable. 



(ii) The site chosen for the kiln is usually on slightly 

 inclined ground, but otherwise of a nature similar to that 

 described for ordinary kilns. It is also prepared similarly, but 

 often is merely levelled, covered with earth and firmly beaten 

 down. 



The size of the kiln also should be considered, its breadth 

 being the length of the pieces of wood and its length varying 

 (usually 13 to 20 feet, but often 25 to 40 feet, and even, accord- 

 ing to v. Berg, 60 feet). The site should be a long rectangle, 

 the longer side of which has a slight gradient, 



(iii) In piling the wood, the first point is to make the base of 

 the kiln ; it consists of three long straight poles which are 

 placed on the ground at equal intervals, lengthways as regards 



