On the Action of the Vegetable Acids on Alcohol. 219 
and leaving it to itself. Thus, although the muriatic acid 
does not form part of this singular substance, and although 
the two bodies which form it are present, it cannot be pro- 
duced except with the concurrence of this acid; a conse- 
quence which, extraordinary as it may appear, is nevertheless 
perfectly accurate, and which we shall presently account 
for: in the mean time let us see if the other vegetable acids 
would not be in the situation of the benzoic acid with re- 
spect to the alcohol. 
Experiment 11.—When we make a solution of 30 gram- 
mes of oxalic acid in 36 grammes of pure alcohol, and, 
after adding 10 grammes of concentrated sulphuric acid, 
disti] it until a little sulphuric ether begins to be formed, 
nothing but alcohol slightly etherized passes into the re- 
ceiver, and there remains 1n the retort a brown liquor very 
strongly acid, from which, upon cooling, nothing but 
crystals of oxalic acid is deposited: but when we dilute 
this liquor with water, there is separated from it an abun- 
dance of matter similar to that which the benzoic acid has 
“given to us, imperfectly soluble in water, and which may 
he obtained pure on washing it in cold water, and by taking 
from it by a little alkali the excess of acid which it retains. 
If we treat the citric and malic acids in the same way, 
we obtain absolutely the same results. The three sub- 
stances proceeding from these three acids resemble each 
other in some of their properties; all of them are a. little 
yellowish, a little heavier than water, without smell, 
evidently soluble in alcohol, from which they are precipi- 
tated by water. They differ from each other in point of 
taste : that which is made with oxalic acid is feebly astrin- 
gent; that which is made with citric acid is very bitter. I 
am not acquainted with the taste of the other. The first is 
the only one which is volatile; it is more so than water, and 
by this means we easily obtain it clear. It would be very 
interesting to know the nature of the whole: [ was natu- 
rally led to suppose, that by distilling them with a solution’ 
of caustic potash I should decompose them, and that the 
first would give me oxalic acid, the second citric acid, the 
third malic acid; that the whole would afford alcohol, and 
that none of them contained sulphuric acid:—all this in 
fact took place. Here, therefore, we have new combina- 
tions of vegetable acids and of alcohol, in the formation of 
which the sulphuric acid acts in the same manner with the 
muriatic acid in the foregoing experiment. 
It became highly probable from the above, that all the 
vegetable acids would act without alcohol in the same way as 
. the 
