308 E. DIVEES AND T. HAGA ! 



Having neglected to cool our solutions we had reason to fear 

 tliat our experiment was a failure; for along with very much 

 precipitation there was a somewhat large evolution of nitrous 

 gases. But for our purpose we had been amply snccessful. The 

 solution was only faintly acid to litmus and remained so for 

 hours. Both it and the precipitate contained lai'ge quantities of 

 barium hydroximidosulphate. The precipitate also contained 

 sulphite and sulphate, the latter being the complement to the 

 nitrous fumes produced. The hydroximidosulphate was extract- 

 ed from the precipitate by a solution of ammonium chloride. 



Calcium salts. — A solution of calcium nitrate, free from 

 magnesium, sodium, potassium, and other ordiary impurities, was 

 heated with well-washed spongy lead until nitrogen oxides and 

 ammonia began to form. The filtered, very alkaline, solution 

 was freed from lead by hydrogen sulphide not used in excess. 

 Calcium hydroxide was then removed by carbon dioxide, (it was 

 interesting to find that, contrary to assertion, carbon dioxide 

 cannot be used to precipitate lead in presence of calcium salt, 

 since calcium precipitates before lead.) A solution of calcium 

 sulphite in sulphurous acid was prepared just before use, in the 

 same way as the barium salt had been, except that carefully pre- 

 pared calcium carbonate took the place of barium hydroxide. 

 With the calcium nitrite somewhat in excess of the calcium 

 sulphite, the solution of the latter was gradually poured into 

 the former, both solutions having ice floating in them at the time. 

 No gas was given off and only a moderate quantity of precipi- 

 tate was formed, which consisted of sulphite. The filtrate was 

 neutral and contained the full quantity of hydroximidosulphate 

 expected. 



Zinc salts. — Zinc nitrite solution was prepared by précipita- 



