FOREST' UTILIZATION 105 



The chimney is filled with inflammable sub- 

 stances (dHed twigs etc.). 



(c) Constructing the kiln proper. 



The kiln should have a parabolic form. It con- 

 sists of two or more tiers of billets placed 

 almost vertically, the bark turned outward, the 

 big end downward, the finest pieces near the 

 chimney and near the circumference, the largest 

 pieces half way between. 



These tiers are topped by a cap, consisting of 

 smaller billets placed almost horizontally. A 

 cylindrical chimney extends through the cap 

 A pyramidal chimney is closed by the cap. 



In the latter case a lighting channel is left oh 

 the ground running radially on the leeward side 

 from the bases of the pyramidal chimney to the 

 circumference. This channel, too, like the 

 chimney, is filled with easily inflammable ma- 

 terial. 



(d) Stuffing all irregularities, interstices, cracks etc. 



showing on the outside of the kiln with small 

 kindling. 



(e) Covering the kiln by two draft-proof layers so 



as to exclude or restrict the admission of air. 



1. The green layer, */ 2 to 24 feet thick, made 



of green branches, grass, weeds and moss. 



2. The earth layer. 4 inches to 6 inches thick, 



consisting of wet loam, charcoal dust 

 etc. 



If kiln is lighted from below, a belt about 

 i foot high running around the circum- 

 ference on the ground is left without 

 earth cover until fire is well started. 



The earth layer and the green layer are 

 thoroughly joined by beating with a pad- 

 dle. 



In large kilns a wooden frame (the armor) 

 consisting of T sections is used to pre- 

 vent the cover from sliding down. 



III. The kiln is lighted early in the morning on a quiet day. 



The cylindrical chimney is stuffed up with wood from 

 above and then closed on top by heavy covering after 

 the fire is well started in the cap. 



The lighting channel, in the case of a pyramidal chim- 

 ney, is similarly stuffed and closed. 



IV. The regulation of the fire and of the draft are the most 



important functions of the attendant who guides the fire 



