§ 88. ALCOHOL. 127 



ture (weight of 1 cubic centimetre = 0.999183 grm.), we 

 can calculate the specific gravity of this distillate, that 

 contains all the alcohol that was in the liquid examined, 

 and from Table Y, learn the per cent of alcohol in the 

 distillate. Then the per cent of alcohol by weight in the 

 solution examined is readily calculated if the weight of 

 10 c.c. of that solution is known. 



Griffin, in his examination of wines (J! «7! Griffin, 

 Chemical Testing of Wines and Spirits), used 25 c.c. 

 of the alcoholic liquid, added its volume of Avater to it, 

 made the volume of the distillate up to 50 c.c, and deter- 

 mined its specific gravity. 



If the substance to be examined contains free acetic 

 acid, add a little soda to the liquid before distillation. 

 The distillate should have no acid reaction. 



b. The alcohol in a wine may be approximately esti- 

 mated by evaporating a measured quantity to about half 

 its bulk, adding water until the original volume is re- 

 stored, and determining the specific gravity of this liquid; 

 then subtract the number by which this specific gravity 

 is greater than one, from the specific gravity of the alco- 

 holic liquid itself, and take the remainder as the specific 

 gravity of the mixture of alcohol and water in that liquid, 

 and get the per cent of alcohol corresponding to this 

 specific gravity from Table V. To illustrate the principle, 

 suppose a wine is examined whose specific gravity equals 

 0.9951 ; after evaporation down to one-half, and adding 

 water until the original volume h restored, the specific 

 gravity is 1.0089. 



0.9951 — 0.0082 = 0.9869. 



Against the specific gravity of 0.9862 in the table, the 

 per cent of alcohol is found to be 0. 



