160 FERMENTATION OF SUGAR. 



grape sugar ; each equivalent of cane sugar takes up 

 and combines with three additional equivalents of 

 water. This change may be thus expressed: 1 equiv. 

 cane sugar contains 12 equiv. carbon, 11 equiv. 

 oxygen, 11 equiv. hydrogen. In passing into grape 

 sugar it takes up 3 equiv. of water, or 3 equiv. oxy- 

 gen, and 3 equiv. hydrogen, and so becomes 1 equiv. 

 of grape sugar, containing 12 equiv. carbon, 14 equiv. 

 oxygen, 14 equiv. hydrogen. 



Carbon. Oxygen. Hydrogen. 

 1 equiv. Cane Sugar, containing 12 11 11 



and 3 equiv. Water " 0.3 3 



forms — — — 



1 equiv. Grape Sugar " 12 14 14 



372. In the second stage of fermentation, this 

 grape sugar is decomposed and separated into alco- 

 hol, carbonic acid, and water : 1 equiv. of grape sugar 

 containing 12 equiv. carbon, 14 equiv. oxygen, 14 

 equiv. hydrogen, during fermentation is resolved as 

 follows : — 



Carbon. Oxygen. Hydrogen. 



1 equiv. Grape Sugar, containing 12 14 14 

 forms — — — 



2 equiv. Alcohol " 8 4 12 

 2 equiv. Water *' 2 2 

 4 equiv. Carbonic Acid "48 



373. In the same way, the changes which occur 

 during the transformation of starch into grape sugar, 

 may be similarly explained : when this happens, 

 each equivalent of starch takes up four equivalents 



