120 Schneider and Rose on the Atomic Weight of Antimony, 



of gas was not too rapid, its quantity did not exceed a milli- 

 gramme, even when the weight of sul])liuret was 6 to 8 grammes. 

 It was with great difficulty that the last traces of sulphur were 

 expelled from the antimony, and it was found necessary to 

 estimate this by dissolving the residual metal in aqua regia; 

 the quartz which remained undissolved was collected and 

 weighed. The solution was then evaporated to dryness, the 

 mass heated to expel free acid, and after treatment by boiling 

 water, it was digested with pure caibonate of soda. The oxide 

 of antimony which separated was hltered off, and the sulphuric 

 acid contained in the filtered liquid estimated as sulphate of 

 baryta. The quantity of sulphur deduced from the sulphate of 

 baryta thus obtained, never exceeded tq\j(J of the weight of 

 antimony. 



Eight experiments made in this way, and with perfectly 

 concordant results, gave a mean of 71*48 antimony and 28'52 

 of sulphur. Taking the equivalent of sulphur as fixed, the 

 equivalent of antimony deduced from these numbers will be 

 1503*8 on the oxygen scale, or 120'3 for hydrogen = 1. The 

 last determiuation of Berzelius had fixed the equivalent at 1613*9, 

 or 129 on the hydrogen scale. 



In confirmation of Schneider's results, Rose has published* a 

 deternunation of the atomic weight of antimony, which had been 

 some time ago effected by Dr. R. Weber. He used for this 

 purpose the solid tcrchloride of antimony, SbCF. This was 

 dissolved in water containing tartaric acid (since water alone 

 decomposes chloride of antimony), and the antimony precipitated 

 by passing sulphuretted hydrogen through the liquid. In the 

 filtrate from the precipitate of sulphide of antimony, the chlo- 

 rine was determined as chloride of silver. It was thus found 

 that 53'15 parts of antimony corresponded to 46*85 of chlorine, 

 from which Rose deduces the equivalent of antimony to be 

 1508,066, or 120-6 on the hydrogen scale. 



It is interesting to notice that the arithmetical mean between 

 the new equivalent of antimony 120*3, and the equivalent of 

 phosphorus (31 '0 Schrotter), is 75*65, which is very nearly the 

 equivalent of arsenic (75*0 Pelouze). Tliere appears therefore 

 to subsist between these three bodies a similar relation to that 

 which exists between barium, strontium, and calcium. 



The new equivalent of antimony will give to many analyses of 

 antimonial compounds which had appeared faulty their due value. 

 Kermesitc contains, according to the old equivalent, 76*25 per 

 cent, antimony. Rose's analj'ses gave 75 '06 per cent, antimony; 

 on the new equivalent it contains 75*04 per cent. In areseaixh 

 on the antimoniates made some time ago, Heffter assigned to 

 •jf Poggendorflfs Annalen, June 1856._ 



