Torrey on an Ore of Zinc. 237 



A. Some of it In fine powder was treated with nitric acid. 

 It readily dissolved, leaving only a small quantity of a light 

 black residue. The solution, on being filtered, was trans- 

 parent and colourless, and yielded quadrangular prisms on 

 evaporation Thf se had a caustic metallic taste, and were 

 very soluble in water and alcohol. When the nitric solu- 

 tion was repeatedly boiled to dryness, and a small quantity 

 of acid added at each operation, some pure oxyd of iron was 

 separated. To the filtered liquor the following tests were 

 applied : — 



(a) The caustic alkalies produced a white precipitate, 

 which was entirely re-dissolved by an excess of alkali: 



(b) Prussiate of potash occasioned a white precipitate. 



(c) Hydro-sulphuret of potash produced the s;ime effect. 



(d) Copper, iron, and other metallic rods immersed in the 

 solution did not occasion any precipitation of metal. 



(e) Muriatic acid did not disturb its transparency. 

 (/) Oxalic acid threw down a white precipitate. 



B. There remaining no doubt that the principal metal of 

 the ore was zinc, the black insoluble residue was next ex- 

 amined. It was not acted upon by acids, except strong ni- 

 tric and sulphuric acids, which it appeared to decompose. 

 When made into a ball with a little mucilage, and ignited, it 

 burned almost entirely away without flame or vapour. 

 Projected into melted nitre, it caused a violent deflagration, 

 it was nearly pure carbon. 



C. One hundred grains of the ore, in fine powder, dissol- 

 ved immediately in diluted sulphuric acid ; leaving one 

 grain of the black powder, which was ascertained in the 

 preceding experiment to be carbon. 



(a) The solution was clear and colourless. It afforded 

 flat four-sided prisms on evaporation, having all the proper- 

 ties of sulphate of zinc. These were re-dissolved in water, 

 and carbonate of potash added until precipitation ceased, 

 and the liquor was boiled to ensure the complete decompp*- 

 sition of the metallic salt. The carbonates of zinc and iron 

 were thus obtained. 



(b) To separate the latter, the whole was re-dissolved in 

 acetic acid, and afterwards boiled to dryness. The acetate 

 of iron was decomposed, leaving the base in a state of per 

 oxyd weighing 3.50 grains. 



Vol. v.. ..No. I. 31 



