69 



both the lime and the carbonic acid which are to 

 used is prepared. 



A kiln of mason work in form of a cone is used, 

 with a height of three or four times the diameter of 

 the base. At the apertures, there are two furnaces com- 

 municationg with the interior by two square bases; 

 at the base also is a hole to discharge the kiln. The 

 opening at the top is hermetically sealed by a cap 

 of cast iron with a tube to which is fitted a pipe of 

 from 8 to 10 inches in diameter, through which the 

 gas escapes into the cylinder of the pump, which 

 sends it into the juice to be operated upon. 



The kiln is charged from the top, by first throw- 

 ing in broken sticks, faggots, then alternately, the 

 lime broken in small pieces and coke in the proportion 

 of one tenth of the latter. When completely charged, 

 fire is set in both furnaces, but the cap is not closed 

 until the operation is well under way, that is to say 

 during two or three days. The fire in both furnaces 

 must be carefully kept up. When the operation is weil 

 under way, the upper part is closed, so that the air is 

 excluded, the openings or cracks are closed with 

 soft clay, and the draft is regulated by the pump 

 which draws the gas produced by combustion and 

 calcination. 



As the carbonic acid gas is not pure when 

 leaving the kiln, it, before reaching the pump, tra- 

 verses a washing apparatus, which frees it of its 

 impurities. 



The daily consumption of lime stone for a factory 



