80 TARTAR EMETIC. 



rsenic contained in the fluid as arsenious acid, is pre- 

 cipitated by a stream of sulphuretted hydrogen. 



54. TARTAR-EMETIC. 

 KOT,Sb0.f+2HO. 



The powdered salt loses all its water at 100. 



The substance is dissolved in about 800 times its 

 weight of warm water, and the solution saturated with 

 sulphuretted hydrogen. Some hydrochloric acid is 

 afterwards added to promote the separation of the ter- 

 sulphide of antimony ; when the liquid has become 

 clear, the precipitate is collected upon a weighed filter, 

 well washed, dried at 150, and weighed. In this case 

 the weight of the antimony may be at once inferred 

 from that of the precipitate. 



The filtrate is evaporated to dryness, the saline 

 residue heated till the tartaric acid is completely car- 

 bonized, the carbonaceous mass digested with dilute 

 hydrochloric acid, filtered off and thoroughly washed. 

 The solution is evaporated, and the residual chloride 

 of potassium gently ignited in a covered crucible, and 

 weighed. 



The amount of the tartaric acid is inferred from the 

 difference. It can be directly determined only by 

 ultimate organic analysis. 



55. ANTIMONY AND LEAD. 

 (Type Metal.) 



The finely-divided compound is oxidized with nitric 

 acid, the solution mixed with ammonia in slight excess, 



