1822.] Pulvis Antimonialis of the Léndon Pharmacopaia. 269 
reasons which I shal! presently mention, I confess I am en- 
tirely of the latter opinion. 
In order to investigate thé chemical nature of the pulvis.anti- 
monialis, | procuréd some at Apothecaries’ Hall : into a retort 
containing 6 ounces of strong muriatic acid, I put 1000 grains 
of the powder and boiled the mixture for some hours, the muria- 
tic acid which distilled, being returned into the retort. A large 
proportion ofthe powder remained undissolved by the acid, and 
when the solution had become clear, some of it was poured into 
water, but no precipitation whatever occurred, 
As the quantity of muriatic acid employed was large, it: may 
be supposed that the excess of it prevented the precipitation of 
any oxide of antimony that might have been dissolved; to .ob- 
viate this objection, I decomposed the muriatic solution by car- 
-bonate of soda, and put the precipitate upon a filter; whilst 
moist, strong muriatic acid was poured upon it, and a solution 
with but little excess of acid was immediately obtained. I mix- 
ed 20 measures of water with one measure of this solution, but 
no precipitation took place, nor did the subsequent addition of 
a much larger quantity of water produce any effect; further to 
remove any objection as to the action of the muriatic acid in 
preventing that of the water, I made the following comparative 
experiment : to one measure of strong muriatic acid, 1 added 
1-30th of its volume of a solution of muriate of antimony, and 
one measure of the above described solution; when 12 mea- 
sures of water were put to this mixture, oxide of antimony was 
readily thrown down, notwithstanding the great excess of acid. 
Although these experiments satisfied me that no oxide of anti- 
mony had been dissolved by the muriatic acid, and that it had 
taken up the phosphate of lime only, I submitted the muriatic 
solution to additional examination. It is well known that pro- 
toxide of antimony, when in a state of loose aggregation, is rea- 
dily dissolved by potash, so that if the muriate of the metal be 
dropped into a solution of the alcali, the oxide at first precipi- 
tated from the acid is immediately redissolved by the potash: 
the muriatic solution obtained was therefore added to a solution 
of potash, precipitation immediately took place, but no excess of 
potash was capable of redissolving it, for when it was saturated 
with muriatic acid, no deposition took place : it is, therefore, 
evident that no oxide of antimony had been dissolved. 
As then the muriatic solution contained merely phosphate of 
lime, it remained to examine the insoluble residuum; | had no 
doubt from its resisting the action of the muriatic acid, that it 
was entirely peroxide of antimony ; it is, however, possible that 
it might be, as already alluded to, a triple compound of phos- 
phoric acid, lime, and oxide of antimony, the latter being inso- 
luble on account of its state of combination. 
To determine this point, I mixed the insoluble residuum with 
