Researches on Wines and other Fermented Liquors. 47 
er this opinion was correct, I added the subcarbonate to a portion of 
wine, as long as it produced the effect just mentioned, when the 
whole was thrown upon a filter. The filtered liquor was of a some- 
what darker color than the wine, but when the subcarbonate was 
now added to it, the separation of the alcohol was speedily effected. 
This result was also produced, when I employed a solution of am- 
monia, instead of the carbonate of potash: the flocculent precipitate 
thus formed, being separated by filtration, the alcohol appeared as in 
the former case, upon the addition of a due proportion of subearbon- 
ate of potassa. These experiments seem to prove, that the separa- 
tion of alcohol in wine, by the common mode of adding subcarbon- 
ate of potassa, is prevented by the tartrate of lime which is libera- 
ted by the first addition of an alkali, and which, perhaps together 
with some of the other matters, forms a flocculent mass suspen- 
ded in the liquor. In my opinion, they constitute a more decisive 
proof of the existence of ready formed alcohol in wine, than any 
which has yet been offered. 
In the analysis of wines and other fermented liquors, the results 
of which are given below, the following process was adopted, for the 
purpose of determining the proportion of alcohol, which they contain. 
A glass bottle with a long and narrow neck, and capable of holding 
1020 grains of distilled water, was filled with the wine under exam- 
ination. This quantity of wine, was now put into a glass retort, 
which was carefully luted to a receiver, so as to prevent the escape 
of vapor. <A gentle heat was applied to the retort, while the re- 
ceiver, was kept constantly cold, by the dropping of water upon it. 
The heat being cautiously managed, towards the end of the process, 
I was enabled to distill off nearly, the whole of the wine, without 
burning the solid residuum. Thus, from 1008 grains of Madeira, 
I distilled over 979 grains, while from the Port, there was a loss of 
nearly 50 grains, in the same measure, owing chiefly, to the greater 
proportion of residuary matter. To make up for this loss, I added 
wine, of the same kind as that distilled, so.as to bring it to the origin- 
al measure of the wine, excepting a small allowance for the space, 
occupied by the solid ingredients. ‘These were now shaken togeth- 
er, and allowed to remain for some time, and the specific gravity 
then carefully determined at the temperature of 60° F. From this, 
the proportions of alcohol and water by weight, were ascertained by 
a reference to the tables of Mr. Gilpin, published in the Philosoph- 
ical Transactions for 1794, and by calculation, the proportions by 
measure, were estimated. 
