528 AUXILIARY FOREST INDUSTRIES. 



give rise to considerable differences in the process of char- 

 coal-making, vertical and horizontal kilns will be described 

 separately. 



In vertical kilns, the wood is piled nearly vertically around 

 stakes in the middle of the kiln, so that the latter assumes 

 the shape of a paraboloid. Horizontal kilns are distinguished 

 from the former kind by their prismatic shape and by the 

 fact that the charcoal is removed from them gradually as the 

 wood becomes carbonised. 



Although the comparison between these methods will follow 

 at the end of the chapter, here it may be mentioned that the 

 vertical arrangement of the wood is that followed usually, as 

 experience shows that it gives the best results. A further 

 distinction depends on whether the kilns are made in the 

 forest and consequently in different places every year as the 

 felling-areas change, near iron-furnaces and other works using 

 charcoal, or in large kilns away from the forests. 



It is evident that in the last case greater care can be taken 

 and better results will follow than when kilns are burned in 

 the forest, frequently under very unfavourable conditions. In 

 spite of this disadvantage, however, forest charcoal-kilns are 

 more economical, as will be seen hereafter. 



1. Paraboloidal Charcoal-kilns. 



There are two methods of making charcoal that do not 

 differ much from one another-^they are the common method 

 and the Alpine or Italian method. The former is practised all 

 over Central and Western Europe, except parts of Styria, the 

 Tyrol, Lower Austria and Lower Bavaria. 



(a) The Common Method of Charcoal-making. 



i. Wood used for Charcoal-making. 



Charcoal-making is a much more important industry in 

 mountain-districts stocked with coniferous forest than in 

 broadleaved woods. Whilst in the latter only the less 

 valuable fire-wood, round billets from early thinnings and 

 stump-wood are carbonised in coniferous forests, frequently 



