188 Mr, R, Phillips on Jameses Powder, [Sept. 



ever, so very trifling, that I am induced to attribute it entirely 

 to the oxide of antimony suspended in the water, and not to any 

 which it held in solution. To another portion of the solution, I 

 added nitrate of lead ; it was rendered rather more turbid by 

 this addition, but not in a greater degree, than might be ex- 

 pected to arise from the presence of phosphate of lime, which 

 IS sufficiently soluble in water to be detected by reagents. 

 Had tartarized antimony been present in such quantity as 

 to influence the nature of the preparation, a copious preci- 

 pitation of tartrate of lead must have occurred, instead of the 

 shght turbidness described. Judging from the effects which I 

 have now detailed, I am certainly of opinion that James's 

 powder does not contain any tartarized antimony, or any combi- 

 nation of it which is soluble in water. 



Fifty grains of James's powder were now boiled in an ounce 

 of muriatic acid diluted with an equal bulk of water, and the 

 ebullition was continued long after any of the powder appeared 

 to be dissolved by the acid. It was evident that a very large 

 proportion of the powder subjected to experiment remained 

 undissolved. This circumstance perfectly satisfied me, that 

 although James's powder might possibly contain some protoxide 

 of antimony, a very large portion was evidently peroxide. I may 

 here remark, that the degree of insolubility of this or any powder 

 containing oxide of antimony, furnishes a ready mode of esti- 

 mating its power ; the less which is left undissolved, the more 

 active the remedy ; for, excepting under pecuhar circumstances, 

 peroxide of antimony is nearly insoluble in muriatic acid ; and 

 when it has been once subjected to a red heat, a very small 

 cjuantity escapes such a degree of cohesion as to remain soluble 

 in an acid. 



Having suffered the muriatic solution to become clear by sub- 

 sidence, 1 poured some of it into a large quantity of water ; not 

 the slightest precipitation occurred : it was, therefore, evident 

 that but little, if any, oxide of antimony had been taken up by the 

 muriatic acid. 



As the excess of muriatic acid employed was considerable, I 

 thought it might possibly retain the oxide in solution even after 

 dilution with water. To discover whether this was the case, I 

 added carbonate of soda to the muriatic solution until precipita- 

 tion commenced. I then poured it into a solution of potash, 

 taking care to have such an excess of the alkali as would imme- 

 diately redissolve any oxide of antimony which might be at first 

 precipitated. 



In order to be certain that any oxide of antimony which the 

 muriatic acid had dissolved should be taken up by the potash, 

 the alkaline solution, containing the precipitated phosphate of 

 lime, was boiled for a considerable time ; the clear solution was 

 poured off", and saturated with acetic acid, by which a very small 

 quantity of precipitate was obtained. Whea this had been 



