396 Analysis of Tartarized Anttmonij. 



Natural History of Mexico. Tlie affairs ol' the mines wear a 

 very favourable appearance. 



TARTARIZED ANTIMONY. 



We extract the following instructive analysis of tartarized 

 antimony, by Mr. R. Phillips, from the Annals of Philosophy. 



A. 100 grains of brilliant small crystals of tartarized anti- 

 mony reduced to powder were heated during eight hours at 

 the temperature of 212° ; they lost only 2'1 grains ; but as bi- 

 tartrate of potash retains the water of crystallization when ex- 

 posed to a much greater heat, I subjected 100 grains of tarta- 

 rized antimony reduced to powder to a higher temperature. 

 Taking the mean of several experiments, I found that the salt 

 lost 7*38 per cent, by several hours' exposure to a sand heat. 

 When one portion, which had lost 7"1< per cent, in this way, 

 was heated by a spirit-lamp, so as to suffer a further diminu- 

 tion of 0*4, it was decomposed, and becoming of a brown co- 

 lour, it emitted the smell of decomposing tartaric acid. I con- 

 sider, therefore, 7*4 per cent, as the quantity of water. 



B. I attempted to ascertain the quantity of oxide of anti- 

 mony in two different modes. First, 1 decomposed a solution of 

 100 grains of the crystals by caibonate of soda, assisted with 

 heat; the mean of two experiments gave 4 1 '35 per cent.; but 

 the alkalies being imperfect precipitants of antimony, I treated 

 the solution afterwards w^ith sulphuretted hydrogen, which 

 gave a mean of 2*8 of precipitate dried at a moderate tempe- 

 rature, and which I conceived to be hydrosulphuret of anti- 

 mony composed of 1 atom of sulphuretted hydrogen 17 + 1 

 atom protoxide of antimony 52 = 69 ; if then 69 contain 52 

 of oxide 2-8 = 2-11, which, added to 41-35, gives 43*46 as 

 the quantity contained in 100 parts of the salt. 



C. After this, and in order to confirm the above statement, 

 I treated two solutions, each of 100 grains, of tartarized anti- 

 mony with sulphuretted hydrogen gas ; the precipitates after 

 being dried on a sand heat gave a mean of 51*25 grains. Now, 

 if we admit, as above supposed, that this precipitate is hydro- 

 sulphuret of antimony, and of which it possesses the appear- 

 ance, tartarized antimony contains only 38*6 instead of 43*46 

 of protoxide of antimony as by Experiment B, for 69 : 52 :: 

 51*25 : 38*6. It may be further observed that the quantity of 

 precipitate obtained in C, as well as the inference as to the 

 quantity of oxide which it contains, agree very nearly with the 

 previous determinations of Thenard. 



These discordant results, repeatedly obtained, puzzled me 

 exceedingly, and I adopted two modes of determining the 

 qui^ntity of oxide existing in the dried hydrosulphuret. 



D. Idis- 



