ARTIFICIAL VENTILATION OF VINEGAR GENERATORS. 79 



The apparatus works as follows : According as combustion 

 in the stove proceeds slowly or quickly by the corresponding 

 position of the regulating register, the air between the heating 

 cylinder and the jacket becomes less or more heated and ascends 



Fig. 24. 



W 



Condensing Apparatus Cross Section. 



with corresponding velocity. But as the further entrance of air 

 can take place only through the pipe R ly the tin coil, and the 

 wooden tube R, a uniform current of air from below to above 

 must pass through all the generators. To regulate the strength of 

 the current for each generator, it is only necessary to close the aper- 

 ture (Fig. 22) more or less by raising or lowering the screw. 



The current of air passing from the wooden tube R into 

 the tin coil carries with it the total amount of evaporated alcohol 

 or acetic acid. By passing through the tin coil, which is cooled 

 by the water, the air itself becomes cooled off, and the greater 



