QUICK PROCESS OF FABRICATION OF VINEGAR. 



55 



by the vapors of acetic acid contained in the air of the work- 

 room. 



In the lower portion of the generator, holes, 0, are bored. 

 These holes are intended for the entrance of air, and in number 



Fig. 3. 



General Form of a Generator. 



may be as many as desired, since the regulation of the current of 

 air is not to be effected on the lower portion of the apparatus, but 

 on the cover. 



There is considerable variation in the dimensions of the gene- 

 rators, some having only a height of 5 feet, with a lower diameter 

 of 3 feet 3 inches, and others again a height of 20 feet or more, 

 with a diameter of up to 6| feet. The small generators have 

 the disadvantage of rapidly yielding heat to the exterior, and 

 hence a correspondingly high temperature must be maintained in 

 the workroom in order to keep up the proper degree of heat in 

 their interior. On the other hand, generators of considerable 

 height have the disadvantage of the shavings, etc., with which 

 the centre space is filled, becoming strongly compressed by their 



