184 



secret, the exact state in which the antimony existed in the powder 

 was not known. The composition of James's Powder was first 

 examined by Dr George Pearson, who pnblished his experiments 

 in the eighty-first volume of the Philosophical Transactions. He 

 believed it to consist of 43 per cent, of phosphate of lime, and 57 

 of peroxide of antimony, x\I. Chenevix, in the Phil. Trans, for 

 1801, gave an account of some experiments which he had made on 

 James's Powder, by which he found it to contain only 44 per cent, 

 of the oxide of antimony. Berzelius, in his Lehrbuch, gives an 

 account of an examination which he had made of a specimen of the 

 powder. Ho found that about two per cent, was soluble in water, 

 and this he found to consist of antimonite of lime. The remainder 

 he found to contain about two-thirds of the antimonious acid, which 

 is identical with the oxide of Dr Pearson, and one-third of phos- 

 phate of lime. The London College of Physicians had, in accord- 

 ance with the views of Dr Pearson, introduced into their Pharma- 

 copoeia an imitation of James's Powder, under the title of Pulvis 

 Antimonialis, which is now adopted by the other British pharma- 

 copoeias. This is prepared by roasting together hartshorn shavings 

 and black sulphuret of antimony, and the product is a mixture of 

 antiraonions acid and phosphate of lime, as was shewn by Mr 

 Richard Phillips in a paper which he published in the twentieth 

 volume of the Annals of Philosophy. Both these preparations are 

 much employed by physicians, but their operation has been fre- 

 quently found to be very uncertain, and by many they are regarded 

 as quite inert. This latter opinion, which is not in accordance with 

 general experience, seems to be supported by the above view of 

 their composition, for the antimonious acid is insoluble, even in 

 strong acids, and the phosphate of lime is well known to be posi- 

 tively inert. This, however, afi'orded no explanation of the fact, 

 that these powders both occasionally produce very decided eflFects ; 

 and, in order to discover the reason of this uncertainty of action, 

 the author was induced to make an examination of some specimens 

 of James's Powder and Pulvis Antimonialis. By treating them 

 with boiling water, it appeared that both these powders contained 

 a proportion soluble in water, which consisted of antimonite of lime 

 and a little soluble superphosphate. The residue was acted on by 

 hot muriatic acid, and was found to contain antimonious acid and 

 phosphate of lime in variable proportion. By the action of sulphu- 

 retted hydrogen on the muriatic solution, it was shewn that there 

 was always present a small quantity of sesqui-oxide of antimony, 



