Page:Popular Science Monthly Volume 29.djvu/86

 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 according 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, molasses, 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 atmosphere.

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 dissimilar in appearance, the fact of their slight difference would be incredible were it not established by science:

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 various kinds of grain used and making the yeast requires very skillful management; so much so that the largest distillers employ a professional and practical chemist to look after the scientific part of the business. The quantity and power of the yeast, in proportion to the quantity 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 carbonic-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