220 On the Action of the Vegetable Acids on Alcohol. 
the foregoing acids. In order to prove it, however, I was 
desirous still to subject some to a rigorous test, and with 
this view I selected the gallic, tartarous and acetic acids, the 
other acids being difficult to procure, or being insoluble in 
alcohol. 
With the gallic acid, the experiment had not all the suc- 
eess which J desired, because I operated upon 10 grammes 
of acid only: the combination constantly took place ; for, 
after having distilled nearly one half of these 10 grammes 
of gallic acid with 12 grammes of alcohol and four grammes 
of sulphuric acid, I found in the retort a liquor which, 
being diluted with water and saturated by potash, yielded 
on anew distillation al] the free alcoho] which it contained, 
and which, when mixed with an excess of potash, furnished 
me still another portion, which certainly must have beer 
combined with gallic acid. 
With the tartarous acid, the experiment on the contrary 
succeeded completely, and exhibited curious results. Here, 
asin the case of the oxalic acid, I employed 30 grammes 
of vegetable acid, 35 grammes of pure alcohol, and 10 
grammes of concentrated sulphuric acid. I distilled until 
a little ether began to be formed: at this period [ put ont 
the fire and allowed the retort to cool slowly. Upon cool- 
ing, the liquor became a thick syrup. I poured water into 
it in vain, in the hope of separating, as in the preceding ex- 
periments, a particular combination of acid and alcohol : 
then, having added successively different quantities of pot- 
ash, I precipitated from the liquor plenty of acidulated tar- 
trite of potash ; afterwards, having saturated it without ex- 
ceeding the point of saturation, having evaporated it, and 
treated it in the cold way by highly concentrated alcohol, 
T obtained by the evaporation of the alcoholic solution a 
substance which, upon cooling, became a thick syrup, more 
easily still than before having been treated by potash and 
alcohol. 
This substance has a brown colour, and is slightly acid, 
nauseous, inodorous, by no means acid, very soluble in 
water and in alcvhol: it does not precipitate the muriate of 
hime ; it precipitates abundantly the mumate of barytes ; 
when we calcine it, it gives out thick vapours which smell 
of garlic, and at the same time it leaves a charry residue, 
not alkaline, which contains much sulphate of potash:—in 
a word, when we distil it with potash, we extract from it 
some very strong alcohol and a considerable quantity of 
tartrite of potash. Itis evident, therefore, that, this sub- 
stance is also a combination analogous to the foregoing ; 
but 
