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In the " Inside Kiln Extinction Method " both air and flue passages 

 are closed as soon as the carbonization is completed, and the product is 

 taken out from the kiln after the perfectfextinction of the fire. 



In the " Outside Kiln Extinction Method," the lower part of the 

 mouth is gradually opened in proportion to the progress of carbonization 

 introducing the air into the kiln so as to elevate the temperature inside. 

 Then the red heated charcoal is taken out, and over which, mixture of moist 

 ash and charcoal dust is spread to extinguish the fire. 



In the " Inside Kiln Extinction Method," one naturally aims to 

 complete the cooling of the kiln as well as the production of perfectly 

 formed charcoal so that the billets should be piled up with great care in 

 the beginning while in the " Outside Kiln Extinction Method " billets are 

 put at random into the still warm kiln. 



II. Carbonization of Billets in the Kiln 



It is of prime importance to know the direction of carbonization 

 within the kiln in connection with the improvement of the construction 

 of it. Limited knowledge on the subject was only known and indeed 

 only on a few European kilns. " If the billets are kindled at the mouth 

 of the kiln, fire will subsequently set into the hinder part thence, proceeding 

 downward, and then it will gradually tend to burn the front." To establish 

 this, we have taken out billets piled in the kiln at a regular interval of 24 

 hours till after the kindling to the complete carbonization. We came to the 

 conclusion that the carbonization process of billets within a Japanese 

 kiln, contrary to the hitherto accepted saying, "forces its way to the roof 

 horizontally from the mouth and thence proceed downward in all 

 directions." 



III. On the Kindling Method 



The methods of kindling so far known are two :— 



1. To kindle at the mouth by the Burner. By this, kindling is 

 easy but billets on the front part in the Kiln are firstly set into fire 

 then perfect conbustion in that part follows, due to the access of air, to 

 the subsequent increase of ash composition in the yield. 



