300 
SELECTED ARTICLES. 
Result obtained. Result calculated. 
Antimonic Acid 2 at 76.73 76.964 
Potassa 1 " 10.97 10.744 
Water 6 " 12.30 12.292 
M. Guibourt does not admit that the diaphoretic antimony 
of the Codex can be a variable mixture of different oxides of 
this metal. The following experiments tend to show the 
opposite conclusion: 
We treated by strong acetic acid the article of the Codex, 
prepared by following exactly the directions of that formulary. 
This acid dissolved a small quantity of the protoxide of anti- 
mony, which can easily be known, after its separation by 
means of the action of alkaline sulphurets, according to the 
observation of Berzelius.* The product, deprived by succes- 
sive maceration with acetic acid of potassa and protoxide of 
antimony, was dried. We obtained 4.50 grammes. We 
placed them in a tube of green glass, to which was adapted a 
second tube, containing chloride of calcium equally weighed. 
The tube of green glass was maintained for an hour, at a dull 
red heat; it lost in weight 0.408 grammes. The tube of 
chloride of calcium was increased 0.22S. 
If we had had to make pure antimonic acid, the quantity of 
water would have nearly equalled the loss given by experi- 
ment; but the loss, in oxygen should have been 0.220, in 
fact, it was only 0.180. This difference arises necessarily, in 
consequence of a part of the product, supposed to be in the 
form of antimonic acid, being really in the state of antimoni- 
ous acid. 
The above demonstrate that washed diaphoretic antimony, 
obtained with two parts of nitre, is a mixture of differently 
oxydized portions of antimony combined with water and 
potassa. 
In order to obtain diaphoretic antimony, entirely formed of 
the antimoniate of potassa, it is necessary to take of metallic anti- 
mony, carefully purified by the process of Liebig, one part, 
* Ann. Ch. et Phys. t. xx, p. 237. 
