ANALYSIS OF A NEW SPECIES OF LEAD-ORE. 255 



whole lead obtained from the 100 grains of ore, 

 amounted to 50.059 grains. 



The solution being mixed with some nitrate of 

 barytes, become slightly muddy, and let fall a 

 white powder, insoluble in nitric acid, and there- 

 fore sulphate of barytes. It weighed 0.8 grainj, 

 and contained 0.112 grain of sulphur. The pre- 

 sence of sulphuric acid, in a solution from which 

 nitrate of lead had separated in crystals, is curious. 

 I do not see how it can be accounted for, unless 

 we suppose BerthoUet's principle of the effect of 

 mass to be to a certain amount true. For there 

 was present in the liquid, an enormous excess of 

 nitric acid, when compared with the quantity of 

 sulphuric acid. Thus, the whole sulphur obtain- 

 ed from the 100 grains of ore, amounted to 11.328 

 grains. 



The nitric acid solution, which had a bluish- 

 green colour, was now mixed with 90 grains of 

 sulphurio acid, and distilled in a retort almost to 

 dryness, to get rid of the nitric acid. The resi- 

 due was dissolved in water, and a plate of zinc 

 being introduced, was allowed to remain till the 

 liquid lost entirely its blue colour, and assumed 

 the light-green tinge, which indicates the presence 

 of iron. Diluted muriatic acid was now poured 

 upon the plate of zinc, till it was completely dis- 

 solved. The copper thrown down by this process^, 

 being dried and weighed, was found to amount^ 

 to 32,5 grains. 



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