Japanese Charcoal Kiln. 401 



which is a sign that all the openings can be closed entirely and the 

 kiln left to cool off in two or three days. 



No water must be applied on the roof during the burning, 

 which is also often protected by a wooden shed. One man is suffi- 

 cient to watch the kiln and cut wood at the same time. 



When the wood is completely carbonized, the charcoal is taken 

 out through the entrance of the kiln and the roof remains intact 

 and is ready for a second burning. A kiln like this can be used 

 steadily from three to five years, when kept in proper condition. 



It can be said, to the advantage of this kiln, that it is not ex- 

 pensive to construct, is maintained very cheaply, and is a de- 

 cided improvement on the customary dirt kiln. The gases can be 

 collected. As a drawback, however, must be considered the long 

 time required for carbonization, which can not be avoided with a 

 kiln made on that principle. 



