170 Analysis of Scientific Books. 



The chemical changes which accompany or constitute fer- 

 mentation, form a very interesting department of the science ; 

 and have derived such illustration from modern inquiry, that 

 we expected his account to be somewhat clear and consistent, 

 at least, if neither ingenious nor profound. But here, alas ! 

 the most luminous emanations of chemical philosophy, in passing 

 through the doubly refracting medium of his pages are depo- 

 larized and dissipated. 



The general result of vinous fermentation, is the conversion 

 of sugar into carbonic acid and alcohol. M. Gay Lussac, in 

 1815, elegantly deduced from the experiments of Saussure, 

 that a volume of alcohol vapour, consists of a volume of defiant 

 gas, and a volume of vapour of water, condensed into a single 

 volume. In determining the density of the vapour of the abso- 

 lute alcohol of Richter, he discovered that when that liquid is 

 diluted with water, the density of the vapour of the mixture is 

 exactly the mean between the density of the absolute alcoholic 

 vapour, and that of the aqueous vapour ; the affinity which con- 

 denses the liquid compound, not operating in the gaseous state. 

 Hence it is evident, that absolute alcohol contains no inde- 

 pendent aqueous matter. We may therefore state the compo- 

 sition of alcohol in numbers thus : 



Density of alcoholic vapour = 1.5972 100.00 lOO.OO 



Hence these 39 parts of water are essential to its constitu- 

 tion ; which may be represented atomically by, 



„ ^ , , cnn (2 atoms carbon") = 2 atoms ole- 



2 atoms carbon = 1.500> i Imogen j fiant gas. 



3 atoms hydrogen = 0.375 r^ j ^^ ^^ j ^ 



1 atom oxygen = 1.000|_^ j hydrogen \- ^ ""^^^ '''''^^'• 



Without this atom of water, therefore, the peculiar compound, 

 alcohol, could not exist. It would in that case become ole- 

 fiant gas. Let us see what our author says on the subject. 

 " Now alcohol of the specific gravity 0.822, contains one-tenth 

 of its weight of water, which can be separated from it ; and if we 

 suppose with Saussure, that absolute alcohol contains 8.3 per 

 cent, of water, then the products of sugar decomposed by fer- 

 mentation, according to the preceding experiment, are as 

 follows : 



Alcohol 47.70 



Carbonic acid 35.34 



83.04 



