100 PHILOSOPHICAL TRANSACTIONS, [aNNO 1791. 



With regard to the nature of this calx, the greatest part of it readily dissolved 

 in marine acid ; and part of what then remained was also dissolved, but with 

 great difficulty and very sparingly ; a minute quantity resisted solution entirely. 



Exper. 12. fioOgrs. of coarsely powdered antimony were mixed with 400 grs, 

 of purified white sand, and calcined as in making Lile's powder. The smell of 

 sulphur continued for 1^- hour, and the mixture was calcined for \ an hour 

 longer. On cooling, a brown powder was obtained which weighed 820 grs. and 

 exposed to 100° of fire, melted into an irregularly figured, blackish mass, full of 

 cavities. In this experiment the loss of weight corresponds nearly to that in ex- 

 periments above related, viz. those in which the deficiency of weight after cal- 

 cining antimony alone was about 294- per cent. The much longer time required 

 in this experiment for carrying oft' the sulphur than in the calcinations with bone- 

 ashes, gypsum, and chalk, perhaps is owing to there being no affinity between 

 antimonial calx and siliceous earth. 



Exper. 13. A medicine is sold by F. Newbery, under the title of " James's 

 Powder for horses, horned cattle, hounds, &c." It is a light clay-coloured, 

 gritty, tasteless substance, in which are seen small spicula. It appears to be 

 nothing more than James's powder for fevers, or Lile's powder above-mentioned, 

 made by calcining antimony and bone-ashes together in open vessels ; because, 

 1st, by exposure to a white heat in close vessels, it turns as white as James's 

 powder. 2dly, it dissolves partially in nitrous acid ; and the remainder dissolves 

 partially in marine acid. The nitrous solution contains phosphoric acid and cal- 

 careous earth ; and the muriatic solution affords Algaroth powder. 



From the whole of the analytical experiments it appears: 1. That James's 

 powder consists of phosphoric acid, lime, and antimon-ial calx ; with a minute 

 quantity of calx of iron, which is considered to be an accidental substance. 



2. That either these 3 essential ingredients are united with each other, form- 

 ing a triple compound, or, phosphorated lime is combined with the antimonial 

 calx, composing a double compound in the proportion of about 57 parts of calx 

 and 43 parts of phosphorated lime. 



3. That this antimonial calx is different from any other known calx of anti- 

 mony in several of its chemical qualities. About ^ of it are soluble in marine 

 acid, and afford Algaroth powder ; and the remainder is not soluble in this men- 

 struum, and is apparently vitrified. 



From the synthetic experiments it appears, that by calcining together bone- 

 ashes, that is, phosphorated lime, and antimony in a certain jn-oportion, and 

 afterwards exposing the mixture to a white heat, a compound was formed con- 

 sisting of antimonial calx and phosphorated lime, in the same proportion, and 

 possessing the same kind of chemical properties, as James's powder.* 



* As James's Powder and other similar prepai'alions of antimony vary considerably, not only in 

 colour but in medical efficacy, according to the degree of heat and other circumstances connected 



