— 76 — 



VIII. Conclusions 



As a result of the researches summarized above we came to the 

 following conclusions : — 



(1) The temperature of carbonization in a Japanese kiln does not 

 as a rule exceed 600°C. 



(2) In the " Outside Kiln Extinction Method " the heat can readily 

 be raised to 900°C. by admitting air through the mouth. 



(3) In the " Outside Kiln Extinction Method," hard charcoal is 

 produced subsequent to the so-called " Finishing combustion." 



(4) In the " Inside Kiln Extinction Method," only 20% of the wood 

 used is obtained in the form of charcoal; if a higher percentage be 

 obtained it is naturally a poorer product which produced disagreeable 

 smoke. 



In the "Outside Kiln Extinction Method," the percentage of the 

 products ranging from 15 to 18% differs according to the " Finishing 

 combustion " process underwent. 



Results of investigations on charcoal produced in Japanese kilns 

 agree well with those stated by Violett so far as specific gravity, igniting 

 point and amount of heat are concerned; in other words, specific gravity 

 of charcoal, etc. are directly proportional to the carbonization temperature. 



