and the Method of making Wines . 34? 
tion. But it is proved also, that though must shut up in 
close vessels undergoes very slowly the phenomena of 
fermentation, it at length terminates, and that the wine 
produced by it is more generous. This is the result of 
the experiments of D. GentiL 
If a little yeast of beer and molasses, diluted in wa- 
ter, be introduced into a flask with a bent beak, and if 
the beak of the flask be opened under a bell filled with 
water, and inverted over a pneumatic tub, at the temper- 
ature of 60 or 65 degrees ; according to my observations, 
the first phenomena of fermentation will always appear a 
few minutes after the apparatus has been thus arranged ; 
the vacuum of the flask soon becomes filled with bubbles 
and foam ; a great deal of carbonic acid passes under the 
bell ; and this movement does not cease till the liquor has 
become spirituous. In no case have I ever seen an ab- 
sorption of atmospheric air. 
If, instead of giving free vent to the gaseous matters 
which escape by the process of fermentation, their disen- 
gagement be checked by keeping the fermenting mass in 
close vessels, the movement then slackens, and the fer- 
mentation terminates only with difficulty and after a very 
long time. 
In all the experiments which I tried on fermentation, I 
have never seen that the air was absorbed. It neither 
enters into the product as a principle, nor into the decom- 
position as an element ; it is expelled from the vessels 
with the carbonic acid, which is the first result of the 
fermentation. 
Atmospheric air, then, is not necessary to fermenta- 
tion ; and if it appears useful to establish a free commu- 
nication between the must and the atmosphere, it is be- 
cause the gaseous substances which are formed in the 
fermentation may then escape, by mixing with or dissolv- 
ing in the surrounding air. It follows also from this 
