357 
and the Method of making Wines . 
Sd, Disengagement of Gas. — The carbonic acid gas 
disengaged from the vintage, and its effects hurtful to 
respiration, have been known since fermentation itself 
was known. This gas escapes in bubbles from every 
point of the vintage, rises in a mass, and bursts at the 
surface. It displaces the atmospheric air which rests on 
the vintage, occupies every where the vacant parts of the 
vat, and flows over the edges, precipitating itself in the 
lowest places on account of its gravity. It is to the for- 
mation of this gas, which takes a portion of oxygen and 
carbon from the constituent principles of the must, that 
we shall in future refer the changes which take place in 
fermentation. 
This gas, retained in the liquor by all the means that 
can be opposed to its evaporation, contributes to preserve 
the aroma and a portion of alcohol which exhales along 
with it. The ancients were acquainted with these means^ 
and they carefully distinguished the product of a free 
from that of a close fermentation ; that is to say, the fer- 
mentation effected in open and that effected in close ves- 
sels. Brisk wines are indebted for that quality to their 
having been shut up in the bottles before their fermenta- 
tion was completed. This gas, being slowly developed 
in the liquor, remains compressed in it till the moment 
when, the effort of the compression having ceased, by 
the opening of the vessels it can escape with force. 
This acid gas gives to all liquors impregnated with it 
a tartish savour. Those mineral waters called gaseous 
waters are indebted to it for their principal virtue. But 
it would be having a very incorrect idea of its real state 
in wine, to compare its effects to those which it produces 
by its free solution in water. 
The carbonic acid disengaged from wine holds in so- 
lution a pretty considerable portion of alcohol. I think 
I was the first who made known this fact, when I show- 
