76 THE POPULAR SCIENCE MONTHLY. 



absolute alcohol and 53*71 parts of. water. When the alcohol and 

 water are mixed together while combining contraction in volume 

 takes place to the extent of 3*71 parts, resulting in 100 parts of proof- 

 spirit. The law declares that the duties on all spirits shall be levied ac- 

 cording to their equivalent in proof -spirits. The hydrometers adopted 

 by the Government for the purpose of testing the degree of strength 

 are graded and marked (0) for water, (100) for proof-spirit, and 

 (200) for absolute alcohol, at a standard temperature of 60 Fahr. 



Alcoholic liquors can be made from any substance that contains 

 saccharine matter already formed by Nature, or from any substance 

 that contains the constituent elements that can be converted by some 

 artificial process into the saccharine principle. In the United States 

 they are generally produced from corn, rye, wheat, barley, rice, mo- 

 lasses, apples, grapes, and peaches ; sometimes from potatoes and beets. 

 Vinous fermentation converts sugar, glucose, or saccharine matter into 

 alcohol and carbonic-acid gas ; the latter passing off into the atmos- 

 phere. 



In order to bring about vinous or alcoholic fermentation five agents 

 are indispensable, viz., saccharine matter, water, heat, a ferment, and 

 atmospheric air. Sugar or saccharine matter in its various forms is 

 the only element from which alcohol can be produced ; the others are 

 mere auxiliaries to the decomposition. 



By establishing the quantity in volumes of the elements of sugar 

 and alcohol, as indicated by the following tabulated statements, and 

 by comparing the constituent elements of the two articles, so dissimi- 

 lar in appearance, the fact of their slight difference would be incredible 

 were it not established by science : 



COMPOSITION OF SUGAR IN VOLUMES. 



Vapor of carbon . . 3 



Hydrogen 3 



Oxygen 1 



COMPOSITION OF ALCOHOL IN VOLUMES. 



Vapor of carbon 2 



Hydrogen : 3 



Oxygen 



Gay-Lussac. 



Take one volume of vapor of carbon and one of oxygen from sugar, 

 which is accomplished by vinous fermentation and distillation, and 

 you have alcohol. 



In order to obtain the best results, the process of scalding the va- 

 rious kinds of grain used and making the yeast requires very skillful 

 management ; so much so that the largest distillers employ a profes- 

 sional and practical chemist to look after the scientific part of the busi- 

 ness. The quantity and power of the yeast, in proportion to the quan- 

 tity of saccharine matter in the mash, must be properly balanced, or in 

 one case the fermentation will be too rapid, developing excessive heat, 

 and consequently a loss of alcoholic vapor passing off with the car- 

 bonic-acid gas, also inducing acetic fermentation, which, under certain 

 conditions, is a destroyer of alcohol ; or, in the other case, if the yeast 

 is too weak, so that it will not convert all the saccharine matter into 



