ALCOHOL. 363 



grape sugar. The latter is then changed into alcohol 

 and carbonic acid, as above described. 



914. COMPOSITION. The composition 



What is the 



composition of of alcohol appears sufficiently from the mid- 

 dle groups of the preceding figure. Accord- 

 ing to the theory of compound radicals 

 it is a hydrated oxide of ethyle. The 

 principal group of the annexed cut, 

 represents a molecule of the radical ; 

 the remaining circles stand for the oxygen and water 

 with which it is combined in alcohol. 



915. PRODUCTION FROM POTATOES AND 



How is aico/iol 



made from po- GRAIN. Wliei'6 molasSCS Or Solution of 



sugar is the material used, alcohol is pro- 

 duced as already shown. But when potatoes and grain 

 are employed as the material, a previous process is 

 necessary by which the starch is converted into sugar. 

 This consists in the addition of bruised malt to the 

 mashed potatoes or grain. The diastase of the malt, 

 has the effect of gradually transforming starch into 

 sugar by its presence, as yeast converts sugar into 

 alcohol. The mixture being kept at a temperature 

 of about 140, in a few hours the transformation is 

 complete. The starchy mixture has become sweet, 

 and receives the name of wort. Brewers' yeast and 

 water being then added to the wort, the conversion into 

 alcohol commences. This is afterward separated from 

 the water and refuse fibre of the potatoe or grain by 

 the process of distillation, described in a subsequent 

 paragraph. 



