1823.] Mr. R. Phillips on James's PoivdeK !8t 



Article IV. 



Analysis of James's Powder, By Richard Phillips, FRS. L, & E. 



In the Annals for October, 1822 (New Series), I gave an 

 analysis of the piilvis antimonialis of the London Pharmacopoeia, 

 by which it appeared that this medicine, procured from two 

 respectable sources, differed very little in composition. The 

 mean of the two results showed this preparation to be com- 

 posed of 



Peroxide of antimony. , 36*5 



Phosphate of lime. . , 63*5 



lOO'O 



Several medical friends have since inquired of me, whether I 

 had made any experiments upon James's powder, which has 

 been shown by Dr. Pearson to consist of oxide of antimony 

 and phosphate of lime. In answer to these inquiries, it 

 might have appeared sufficient to refer to Dr. Pearson's ana- 

 lysis, pubUshed in the Philosophical Transactions for 1791. 

 In the course of 30 years, however, chemical research has 

 been so actively pursued, that it would be very remarkable 

 if the nature of the oxides of antimony was not better understood 

 than when Dr. Pearson performed his analysis. Without, how- 

 ever, entertaining any suspicions that the results of his investi- 

 gation were incorrect, it appeared to me to be a subject worthy 

 of further inquiry, whether the antimony in this powder is in the 

 same state as I found it to be in the antimonial powder. The 

 nature of the oxide formed no part of Dr. Pearson's inquiry, nor 

 was the difference of power between the protoxide and peroxide 

 of antimony so well understood as at present. 



Having procured some James's powder,* I first directed my 

 attention to the effect produced by boiling it in distilled water; 

 my reason for this was to ascertain whether it contained any 

 tartarized antimony, a suspicion of which was entertained by the 

 late Dr. George Fordyce. 



The water in which the powder had been long boiled was 

 extremely turbid, and remained so for a long time ; nor could 1 

 render it perfectly clear even by filtering it through several folds 

 of paper. 



On adding some solution of sulphuretted hydrogen to the fil- 

 tered but slightly turbid water, perceptible traces of the presence 

 of oxide of antimony were indicated by the appearance of the 

 well-known orange-coloured precipitate ; the effect ,was, how- 



• From Messrs. Newberry's, St, Paul's Church-yard, 



