VINEGAR. 371 



as is represented in the preceding figure. It will be ob- 

 served that the oxygen added is just sufficient to sup- 

 ply the place of the hydrogen removed in the formation 

 of aldehyde. The latter substance being a hydrate of 

 the protoxide of acetyl, acetic acid is a hydrated terox- 

 ide of the same radical. The presence of yeast or 

 some other similar ferment, is essential in the produc- 

 tion of vinegar, as well as in that of alcohol. 



Describe the 934. PROCESS OF MANUFACTURE. A 



process. f ew y ears since, vinegar was exclusively 



produced by the souring of .wine or cider. At pres- 

 ent, large quantities are made from alcohol, by diluting 

 it with water, adding a little yeast, and then exposing 

 it to the action of the air. This is best accomplished 

 by allowing the diluted alcohol to trickle through shav- 

 ings, packed in well ventilated casks. A few passages 

 through the cask suffices to convert the liquid into 

 vinegar. The addition of yeast is unnecessary in pro- 

 ducing vinegar from cider or wine, as these liquids con- 

 tain a substance which acts as a ferment. The vapor 

 of alcohol may be readily converted into acetic acid 

 by contact with platinum black. The property of pla- 

 tinum to produce oxidation in similar cases, has been 

 already explained. 



935. CHLOROFORM. Chloroform is best 



Howischloro- . ...... 



formprepar- obtained by distilling pure alcohol with 



water and bleachin g powder. Its mole- 

 cule consists of two atoms of carbon, and 

 one of hydrogen, combined with three of chlorine. The 

 carbon and hydrogen atoms are regarded as more inti- 

 mately combined to form the radical formyl. Chloro- 



