1823.] Mr, R, Phillips on laments Powder* 189 



washed, solution of sulphuretted hydrogen was added to it, and 



fave sHght traces of the presence of oxide of antimony : it was, 

 owever, so evidently mixed with some impurity that the colour 

 was reddish-brown instead of bright-orange : the quantity was 

 also so extremely small that it would have been nearly impossible 

 to have ascertained its weight. 



1 may here observe, that it is scarcely requisite to add the 

 acetic acid in such proportion only as shall perfectly saturate 

 the alkali holding the oxide of antimony in solution, for acetic 

 acid appears to possess very little solvent power with respect tq 

 this oxide ; for when muriate of antimony is dropped into strong 

 acetic acid precipitation occurs exactly as it does in mere water. 



The white residuum insoluble in muriatic acid was now 

 washed ; after being dried by the heat of a spirit-lamp, it 

 weighed 28 grains = to 56 per cent. It was then mixed witl^, 

 carbonaceous matter, and heated slightly to redness ; muriatic 

 acid added to it readily gave a solution without the assistance of 

 heat, which was decomposed by water. It is, therefore, evident, 

 that the insoluble residuum was peroxide of antimony, which, 

 by treatment with carbonaceous matter, was reduced to the state 

 of protoxide, and rendered soluble in muriatic acid. 



The phosphate of lime precipitated from the muriatic acid by 

 the potash, washed and dried, weighed 21- 1 grs. = 42*2 per 

 cent. 



From the experiments now detailed, it appears that James's 

 powder is a mixture of 



Peroxide of antimony. 56*0 



Phosphate of lime , 42*2 



Oxide of antimony, impurity, and loss. . 1'8 



100-0 



Upon referring to Dr. Pearson's analysis, it will be observed, 

 that when he heated 50 grains of James's powder with muriatic 

 acid, only 14 grains remained undissolved by the acid, which is 

 precisely half what resulted in my experiment. This difference 

 is the more remarkable, because my statement of the composi- 

 tion of this powder agrees almost precisely with that given by 

 J)r. Pearson, viz. 



Oxide of antimony 57 



Phosphate of lime ^ ww*^»4»li^*iM*i . 43 j 



100 



The greater solubility of the oxide of antimony stated by 

 Dr. Psarson, would seem to render it probable that the medicine 

 in question was originally prepared in a different mode from that 

 now adopted, and it is certainly possible that it may have for- 

 merly contained protoxide of antimony, of which it is now desti- 

 tute. As now prepared, it differs from the pulvis antimonialis of 



