7 1 n woon-cARP.oxi.^ATrox. 



(b) Situation of kiln. — The nature of the site of a kihi has an 

 important ctlV'ct on the yiekl of charcoal, a new site yielding less 

 than one repeatedly used. 



(c) State of the weather. — The weather has important efiects 

 on the yield of a kihi. Uniformly still weather, which fre- 

 quently occurs in late summer and autumn, is best ; changeable 

 weather, accompanied by storms, is most unfavourable. Pro- 

 longed dry weather is as unfavourable as continual rain : in the 

 former case the covering is liable to crack, in the latter it may 

 burst or the process of carbonisation be too prolonged. 



Although in some Alpine districts charcoal-making continues 

 throughout the year, even during winter ; as a rule it is carried 

 on only during summer and autumn, when experience shows 

 that the greatest yield is obtained. 



(d) Process of burning. — It is evident that the yield must be 

 reduced when the cooling down of a kiln is more than usually 

 prolonged, and the charcoal exposed to a greater total amount of 

 heat than is really necessary. The burner, except under certain 

 unforeseen circumstances, can control the cooling process if he 

 piles the wood correctl}', distributes the pieces in different parts 

 of the kiln according to their size and specific gravity, and con- 

 ducts the burning carefully. Slow, careful progress, especially 

 during the earlier part of the burning, not only yields heavier 

 charcoal but also a larger volume of it. 



(e) Duration of the burning. — The length of time during which 

 a kiln should burn is very variable and depends on its size, the 

 tlimensions and degree of dryness of the billets, the quicker 

 or slower action of the fire (depending on the site, arrangement 

 of the wood, weather, &c.) and many other circumstances. 

 .Small kilns with small billets will evidently burn more quickly 

 than large kilns with large billets : in windy or moderately damp 

 weather the l-urning can be effected more quickly than in still, 

 dry weather. 



Kilns of sprucewood containing <S00 — 1,'200 stacked cubic 

 feet are carbonised in G — H days, beechwood in somewhat less 

 time. Large kilns containing 4,000 — 8,000 cubic feet, in 

 favourable weather, require about 4 weeks to burn, and in un- 

 favourable weather 5 — (> Aveeks. There is a considerable loss of 

 charcoal when the carbonising process is driven too quickly. 



