THE PARABOLOIDAL PIT-KILN, 215 



The Indian charcoal-burner is often accustomed to empty out 

 even a large kiln in a single operation, and to prevent all risk of 

 fire, he deluges the hot charcoal with water. Nothing could be 

 more reprehensible, as the moistened charcoal not only breaks up 

 into innumerable small fragments, but also loses quality. 



As soon as the charcoal is cool enough to be handled, it should 

 be sorted and at once put away under shelter, for charcoal absorbs 

 moisture greedily and becomes depreciated thereby. If there is a 

 demand for it, the very small charcoal that is mixed up with the 

 dust of the kiln should be sifted out, constituting then the lowest 

 class of charcoal. 



However skilfully the carbonization has been conducted, a very 

 appreciable portion of the wood will always be found incompletely 

 charred. Such pieces, as already recommended before, should be 

 utilised in new kilns as filling material for the chimney and hollows 

 and for placing next to the chimney. But if they are very nume- 

 . rous, it will be found convenient to complete their carbonization 

 sej)arately in a kiln made up entirely of such stuff; mixed up 

 with fresh wood in any other manner than that indicated above, 

 they would be reduced to ashes by the time the latter was car- 

 bonized. 



Aetiole 2.— The Paeaboloidai, Pit-Kilk. 



In this system, a circular pit from 1 to 2 feet deep is dug, with 

 a level bottom and sides sloping, enough not to fall in. The bottom 

 of the pit is first strewn over with a layer, from 4 to 6 inches thick, 

 of dry leaves and twigs, and then the kiln is built up. The object 

 of this foundation of loose and highly combustible material is 

 (i) to preserve the wood to be carbonized from direct contact with 

 the soil, which, besides that it may itself be originally moist, must, 

 during the process of the carbonization, become sodden with the 

 liquid products of distillation, and (ii) to ensure the fire extending 

 amongst the wood at the bottom of the kiln. The pieces of wood 

 to be carbonized are laid horizontally — some radially, others tan- 

 gentially. Hence, to pack close, they must be of all sizes. Before 

 beginning a new layer, all empty spaces in the one just completed 

 should be filled up with small pieces, preferably of dry wood. It 

 is superfluous to add that every layer should be arranged as hori- 

 zontally as possible. 



■ The manner of forming the flue requires to be described. The 

 billets forming its sides in alternate layers of the wood are arrang- 



