4*20 ilf. Rose on the Compounds of [Dec. 



colours. The native is lead crey ; its composition has been 

 demonstrated by Berzelius. ft is analogous to the oxide of 

 antimony with 3 atoms of oxygen, for it dissolves in hydrochloric 

 acid without leaving any residuum, and with the disengagement 

 of sulphuretted hydrogen only. 



The same sulpnuret is obtained by passing a current of sul- 

 phuretted hydrogen through a solution containing oxide of 

 antimony; but it has an orange colour, almost like that of the 

 golden sulphuret. It becomes brownish by drying, and then 

 assumes an aspect more similar to that of kormes. The same 

 sulphuret is obtained by passing sulphuretted hydrogen through 

 a solution of tartar emetic, or through a solution of butter of 

 antimony in water and tartaric acid. 



M. Berzelius first proved that the composition of kermes 

 mineral is exactly similar; its colour, however, is brownish- red. ''^ 



The deuto-sulphuret of antimony with 4 atoms of sulphur has 

 an orange colour a good deal like that of the golden sulphuret. 

 It is formed when sulphuretted hydrogen is passed through a 

 solution of antimonious acid. Tartaric acid, however, must not 

 be added for the purpose of enabling us to dilute the liquid with 

 ■water, but only hydrochloric acid.f The best method of making 

 a solution of antimonious acid is to dissolve antimony in aqua 

 regia, and evaporate the solution to dryness. The antimonic 

 acid formed is then to be converted into antimonious acid by ared 

 heat ; the latter fused with caustic potash, and the fused mass 

 heated with hydrochloric acid and water till a clear liquid is 

 obtained. I precipitated this solution by sulphuretted hydrogen, 

 and the sulphuret obtained, after being carefully dried, was 

 decomposed by hydrogen. I obtained in one experiment 1-305 

 gramme (20*1 grs.) of antimony from 1*973 gramme (30*5 grs.)of 

 sulphuret, and in another 0-977 gramme (15*1 grs.) of antimony 

 i'roin l-46'8 gramme (22*7 grs.) of sulphuret. Its composition, 

 therefore, according to the first trial, is per cent. 



Antimony 66*14 



Sulphur 33-86 



100-00 

 and, according to the second, 



Antimony 66-55 



Sulphur 33-45 



100-00 



♦ I analyzed a kermes prepared by digesting black sulphuret of antimony in a solu- 

 tion of carbonate of potash. I expelled tlie hygrometric moisture by a gentle heat, and 

 deconipossd it by hydrogen. ()•? 19 gramme (J I I grs.) of kermes gave 0*52 gramme 

 (8 grs.) of antimony: its composition, therefore, was antimony 72*32, sulphur 27-68. 



-|- The addition of tartaric acid to antimonious acid affords very remarkable results. 

 I shall give a separate memoir on that subject. 



