360 On the Cultivation of the Vine y 
in proportion as it is precipitated on the floor, by scatter- 
ing in several places milk of lime, or quicklime. A place 
rendered noxious by this pernicious gas may be purified 
by throwing upon the floor and against the walls quick- 
lime diluted in water : a caustic alkaline ley, such as 
soapmakers’ ley or ammonia, will produce a similar ef- 
fect. In all cases the gaseous acid instantly combines 
with these matters, and the external air descends to oc- 
cupy its place. 
3d, Formation of Alcohol . — The saccharine principle 
exists in must, and makes one of its principal characters : 
it disappears by fermentation, and is replaced by alco- 
hol ; which essentially characterises wine. 
We shall mention hereafter in what manner this phe- 
nomenon, or this interesting series of decompositions and 
productions, may be conceived. Our business at present 
is to indicate the principal facts which accompany the 
formation of alcohol. 
As the object and effect of spiritous fermentation are 
merely the production of alcohol by decomposing the sac- 
charine principle, it thence follows that the formation of 
the one is always in proportion to the destruction of the 
other, and that the alcohol will be more abundant as the 
saccharine principle is greater : for this reason, the quan- 
tity of alcohol may be augmented at pleasure by adding 
to the must the sugar which seems to be wanting. 
It invariably follows from these principles, that the 
nature of the vintage in fermentation is every moment 
modified and changed : its smell, taste, and other cha- 
racters, are continually varying. But as there is a very 
constant progress in the process of fermentation, it may 
be followed in all its changes, which may be considered 
as invariable signs of the different states through which 
the vintage passes. 
1st, Must has a sweetish odour, which is peculiar to 
