CHARCOAL-MAKING. 



533 



possible round the shaft, with their split sides inwards, followed 

 by larger pieces, so that at a distance of about half the radius 

 of the kiln the thickest pieces, which burn most slowly, are 

 placed, and smaller billets outside these, as shown in 

 Fig. 311. After some progress has been made in the lower 



on of diiircoal-kiln. 



tier of billets, the upper tier is commenced and the two 

 tiers continued together till the kiln has attained its full 

 circumference. 



If the kiln is to he kindled from below, a kindling-passage 



Kiir. :}\'2. -Vertical kiln with supports. 



is left communicating with the flue ; this is effected by placing 

 on the ground from the opening in the flue to the edge of the 

 kiln a thick log, which is gradually drawn away during the 

 piling of the lower tier, leaving a hollow passage. The billets 

 placed above this log should be somewhat shorter than the 



