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SELECTED ARTICLES. 
Our experiments have led to the confirmation of this result. 
It is known how great is the difficulty of separating the differ- 
ent oxides of antimony; it is so great, that the most expe- 
rienced analysts of our age regard it as almost insurmountable. 
The following is the method we have followed in en- 
deavoring to arrive at this end. 
Diaphoretic antimony was treated several times in succes- 
sion by acetic acid, at first weak, then more and more concen- 
trated. This acid removed the potassa, and the protoxide of 
antimony; the latter was converted into an insoluble sulphuret, 
by means of sulphuretted hydrogen, and the quantity of sul- 
phuret gave the proportion of oxide contained in the mixture. 
To know the proportions of antimonious and antimonic 
acids, we dried the mixture of these two oxides, freed from 
the protoxide, at a temperature of 100°. The product thus 
dried, was introduced into a tube of green glass, provided 
with a leaf of copper, such as is employed for the elementary 
analysis of organic substances. To this was adapted a second 
tube, of dry chloride of calcium, as is practised in these 
analyses. Both tubes were exactly weighed. Heat was 
applied with caution, and continued at a dull red for an hour. 
The oxygen disengaged itself, with the water, at the commence- 
ment of the operation, but at its termination oxygen alone 
was disengaged. The heat was continued some time, until 
after bubbles ceased to form. The apparatus having been 
cooled, the two tubes were weighed. The increase in weight 
of that containing chloride of calcium, gave the quantity of 
water. The diminution in weight of the tube containing the 
oxides, indicated both the loss in water and oxygen. The 
quantity of water being known, it was easy to deduce the 
quantity of oxygen, which represented that which the anti- 
monic acid had lost' by its conversion into antimonious acid. 
longer has a perceptible taste ; finally throw the deposit upon a linen cloth, 
and dry by a stove. 
Diaphoretic antimony should be of a perfect white color; it is composed 
of antimonic acid 87.75, potassa 12.25. J. C. 
