710 WUOD-CARBONISATION. 



and tbe kindling cavity also filled with a heap of charcoal. After 

 a few hours the Hue is burned through from below, and must be 

 repeatedly filled, as long as the glowing charcoal continues to 

 sink. "When all danger of explosion is over and the wood in the 

 dome is thoroughly kindled, it is covered with paste, and the 

 burning henceforth conducted as in ordinary kilns. 



In Alpine kihis the filling which has just been described must 

 be most carefully conducted ; as a rule, only charcoal is used for 

 the purpose. 



This method then differs from the ordinary method of burning 

 kilns, in the following points : — 



(i) The large dimensions of the pieces of wood to be carbonised 

 and the fact that they are not usually 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 

 wood which are being carbonised. 



(iii) The large dimensions of the kilns. 



(iv) Only one covering being ajiplied to the kilns, which is 

 usually thick and requires special supports. 



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

 if not always, from above. 



2. Kilits uitJt WooiJ piU'd IlorizoiitaUii. 



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 chieily coniferous; the pieces arc 

 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 densely piled. 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 kihi is usually on slightly inclined 

 ground, but otherwise of a similar nature to that described for 

 ordinary kilns. It is also similarly prepared, but often is merely 

 levelled, covered with earth and linulv beaten down. 



