THE STUDY OP TARTARIC ACID. 37 
to ascertain the manner of action of the simple tartrate of an- 
timony. But we have not been able to obtain this salt in a 
pure state. The processes stated in the works on chemistry, 
do not conduce to this end. That by which we have suc- 
ceeded best, is to saturate a solution of tartaric acid with oxide 
of antimony, to concentrate and precipitate by strong alco- 
hol. But in this case there is certainly a mixture of salts in 
different states of saturation, and at each operation there was 
disclosed, by analysis, different quantities of oxide of antimo- 
ny. We have, it is true, proven that this salt, dried at 100° 
c, looses an additional quantity of water when raised to the 
temperature of 250° c; but, having under trial a mixed pro- 
duct, we deemed it useless to determine the precise quantity 
lost. 
The loss of two atoms of water, which tartar emetic under- 
goes when heated to 250°, has necessarily led the chemists 
who have observed this, to the consideration whether it does 
not contain the acid C 8 H 8 10 . It is desirable to know whence 
the water, which separates at that temperature, is derived. 
M. Liebig has given two hypotheses; one, that the water is 
contained ready formed in the tartaric acid, and is separated 
at the temperature of 250° c; in the other, that a part of the 
oxide of antimony is reduced, forming with the hydrogen of 
the acid, the water yielded in the experiment. M. Liebig 
prefers this latter, the partial reduction of the oxide of anti- 
mony, and he concludes that we can no longer consider as 
hypothetical, the true presence of a base contained in the me- 
tallic state, in combination with an oxygenated acid. 
This partial reduction of the oxide of antimony, in which 
two-thirds of the antimony enters as a metal into combination, 
while the other third remains in the state of oxide, does not 
appear to have great probability. Experiment is not favor- 
able to it; for if we accomplish the decomposition of tartar 
emetic, or of soluble cream of tartar with care, and so as only 
to carbonize the organic matter, we find, it is true, in the re- 
sidue, metallic antimony perhaps, which will not dissolve in 
weak acids, but in the carbonaceous residue furnished by the 
