38 
SELECTED ARTICLES. 
soluble cream of tartar, it is impossible to discover any trace 
of boron, because this body offers greater obstacles to reduc- 
tion than the oxide of antimony. 
M. Liebig considers the formation of oxalic acid, and hy- 
drated acetic acid, during the decomposition of a tartrate by 
an excess of caustic potassa, as a conclusive argument, against 
the pre-existence of two atoms of water which separate from 
the tartar emetic. "If we admit," says M. Liebig, " that 
tartaric acid contains, already formed, two atoms of water, we 
are led to admit, likewise, that acetic acid, considered as an- 
hydrous, either contains one atom of water, or is formed by 
the addition of one atom of water, which passes to a state 
from which it can no longer be eliminated by bases." 
We can see that the difficulty with M. Liebig is to admit 
that the elements of water, existing as water in tartaric acid, 
can, in passing to acetic acid, assume another chemical rela- 
tion. This, however, can no longer appear astonishing amidst 
so powerful an atomic reaction as that which conduces to the 
conversion of tartaric into two other different acids. 
We would only desire to render it evident that the theore- 
tical reduction of the oxide of antimony, and also of the bora- 
cic acid, is not absolutely necessary to the explanation of the 
facts. 
We can in a manner equally simple and easy, represent 
the composition of tartaric acid, and of the tartrates, by adopt- 
ing for the equivalent of the acid, the formula C 8 H 4 8 , and 
admitting that this acid always unites with four equivalents of 
base, water, or metallic oxide, two of these equivalents being 
more strongly retained than the others. 
Representing tartaric acid by C 8 H 4 8 by T, the tartrates 
will have the following composition: 
T + 2HO-fHOHO = crystallised tartaric acid. 
T + 2HO + HOKO = cream of tartar. 
T+2HO + KOKO= neutral tartrate of potassa. 
T + 2HO + KONaO=Rochelle salt. 
T + 2HO + PbOPbO = tartrate of lead. 
