PRODUCTS OF ACETOUS FERMENTATION. 49 



The principal requirement in our opinion is to provide the 

 generator with a suitable ventilator, which will allow of the pas- 

 sage through the generator of exactly the quantity of air required 

 foTtEe conversion of the alcohol into acetic acid, and is so con- 

 structed that the vapors of alcohol and acetic acid (or at least the 

 larger portion) carried away by the current of air are condensed 

 and thus regained. 



A vinegar generator has frequently been compared to a furnace, 

 and in continuation of this comparison it may be said, that the 

 construction generally used is a furnace lacking every arrange- 

 ment for the regulation of combustion. In such a furnace as 

 much fuel is burned as corresponds to the quantity of oxygen 

 entering, while in a furnace of suitable construction the combus- 

 tion of fuel can be accurately regulated by increasing or de- 

 creasing at will the supply of air by means of a simple con- 

 trivance. 



A vinegar generator of suitable construction should be provided 

 with a similar arrangement. If the thermometer on the apparatus 

 shows too low a temperature hence too slow a process of oxida- 

 tion the course of the operation can in a short time be accel- 

 erated by the production of a stronger current of air and the 

 temperature correspondingly increased. If, on the other hand, 

 oxidation proceeds too rapidly, which on account of the high 

 temperature then prevailing in the apparatus is accompanied by 

 considerable loss of substance, it can be quickly reduced to 

 within the correct limits by decreasing the current of air. An 

 apparatus unprovided with a ventilator is left more or less to 

 itself, while one provided with such an arrangement is under the 

 entire control of the manufacturer. 



