Alcohol exists in fermented Liquors. 213 
Twenty measures of alcohol, specific gravity ,82500, 
were mixed with eighty measures of distilled water coloured 
with logwood, and rendered slightly acid by supertartrate 
of potash. Four measures of a concentrated solution of 
the subacetate of lead were added to this mixture, and the 
whole poured upon a filter. A precipitate was thus col- 
lected of a deep purple colour, which appeared to consist 
of oxide of lead combined with tartaric acid and the co- 
louring-extractive matter. 
The filtered liquot was perfectly transparent and colour- 
less, and afforded, on the addition of subcarbonate of pot- 
ash, 19,5 measures of alcohol *. 
Finding that the separation of alcohol by subcarbonate 
of potash from mixtures of spirit and water was nearly 
complete, and that colouring-extractive matter and tartaric 
acid might be removed from such mixtures by the subace- 
tate of lead, I proceeded to examine wine by such modes of 
analysis. 
The following results gvere obtained by these and other 
comparative experiments. 
1. One part by measure of a concentrated solution of 
subacetate of lead was added to eight measures of common 
port wine: the mixture having been agitated for a few 
minutes, was poured upon a filter.—The filtrated liquor 
was perfectly colourless, and the addition of dry subcar- 
bonate of potash effected a rapid separation of alcohol f. 
One hundred measures of the wine thus treated afforded 
22,5 measures of alcohol. 
2. Eight ounces of the wine employed in the last experi- 
* Pure subcarbonate of potash, obtained by igniting the carbonate, was 
employed in these experiments, I found that about 19,5 parts of alcohol 
were separated in the course of four hours, by the addition of 50 parts of 
the subcarbonate to a mixture of 20 parts of alechol by measure with 80 
of distilled water, and that no further separation took place. The alcohol 
is always slightly alkaline, probably from containing a small portion of the 
solution of the subcarbonate, or of pure soda; but as this did not interfere 
with the object of the experiment, it was not particularly attended to. 
When the subearbonate was added to a mixture of four parts by measure 
of alcohol with 96 of water, no separation was effected.—A mixture con- 
taining 8 per cent. of alcohol afforded about 7 parts—one containing 16 
per cent. about 15,5, and where the proportion of alcohol exceeded 16 per 
cent. the quantity, indicated by the action of the subcarbonate, was always 
within 0,5 per cent. of the real proportion contained in the mixture. So 
that in the examination of wines containing less than 12 per cent. of alco- 
hol, the method described in the text is somewhat exceptionable. ‘The 
above experiments were made in glass tubes varying in diameter from 0,5 
inch to 2 inches, and accurately graduated into 100 parts. 
4+ When any excess of the subacetate had been employed, a portion of 
carbonate of lead was thrown down; but this did not interfere with the 
subepquent separation of rhe alcohol. 
O03 ment 
