Researches on Wines and other Fermented Liquors. 45 
_ Nees D’Esenbeck has proposed a method of detecting artificial 
coloring matter in wine which is said to be more certain in its indica- 
tions. This consists in dissolving one part of alum in eleven parts 
of water and one part of carbonate of potassa in eight parts of water. 
The wine is mixed with its own bulk of the solution of alum which 
renders its color more bright. To this, the alkaline solution is now 
added little by little, taking care not to precipitate the whole of the 
alumina. The alumina precipitates with the coloring matter of the 
wine in the form of a lake, whose shade of color varies with the nature 
of the coloring matter, and which, when combined with an excess of 
potash, assumes another tint also varying with the coloring matter 
combined with the alumina. In order to obtain correct results it is 
necessary to make comparative experiments with pure wine.—See 
Berzelius’ Traité de Chimie. 
Specific gravity of Wine.—It has long been known, that the spe- 
cific gravity of wine gives us no information, as it does in the case 
of distilled liquors, of the proportion of alcohol which it contains. 
Direct experiments on this point have been made by Brisson and 
Brande. I, also, accurately determined the density of several vari- 
eties of wine and other fermented liquors. ‘The following are some 
of the results. 
Madeira, mean of three kinds, - » - 0.98659. 
Sercial Madeira, ep sr epcl ately - 0.98606 
London Particular, -. = - - - 0.98860 
Port, mean of two kinds, = - - - 0.98203 
Sauterne, - . - 0.99511 
Claret, mean de two ‘eae. - - - 0.99490 
American Wine, . - - - 1.00702 
Cider, mean of two kinds, - - - 1.03400 
Metheglin, - - - - - 1.08964 
Alcohol in Wine.—It has been a subject of some cohtroversy, 
whether alcohol exists, ready formed, in wine, or whether it is gener- 
ated by the heat employed in the process of distillation. The lat- 
ter opinion was supported by Fabroni (Ann. de Chim. xxx, 220) ; 
but its fallacy has been completely exbibited, by the able investiga- 
tions of Mr. Brande and Gay Lussac. 
The following statements, seem to be conclusive, as to a exis- 
tence of ready formed alcohol in wine. 
1. Alcohol can be obtained from wine by distillation, in vacuo, 
at the temperature of 60° F., which precludes the idea, that it is 
