54 



ALCOHOL 



Alcobmetrical Tabl* of real Strength, by M. Gay-Lussac (continued). 



The boiling point of mixtures of alcohol and water likewise differs with the strength 

 of such mixtures. 



According to Gay-Lussac, absolute alcohol boils at 78-4 0. (173 F.) under a 

 pressure of 760 millimetres (the millimetre being 0-03937 English inches). When 

 mixed with water, of course its boiling point rises in proportion to the quantity of 

 water present, as is the case in general with mixtures of two fluids of greater and 

 less volatility. A mixture of alcohol and water, however, presents this anomaly, ac- 

 cording to Soemmering : when the mixture contains less than six per cent, of alcohol, 

 those portions which first pass off are saturated with water, and the alcoholic solu- 

 tion in the retort becomes richer, till absolute alcohol passes over ; but when tho 

 mixture contains more than six per cent, of water the boiling point rises, and the 

 quantity of alcohol in the distillate steadily diminishes as the distillation proceeds. 



