Torrey on an Ore of Zinc. 237 



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

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

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

 parent and colourless, and yielded quadrangular prisms on 

 evaporation. These 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 follow^ing tests were 

 applied : 



(a) The caustic alkalies produced a white precipitate, 

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



(h) Prussiate of potash occasioned a white precipitate. 



(c) Hydro-sulphurct of potash produced the same effect. 



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

 solution did not occasion any precipitation of metal. 



Muriatic acid did not disturb its transparency. 

 /) Oxalic acid threw down a vhite precipitate. 



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 w*as 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 decompo- 

 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....N0. J. 31 



