256 ANALYSIS OF A NEW SPEGIilS OF LEAD- ORE*. 



A plate of fresh zinc was introduced into the 

 green solution, and allowed to remain till the co- 

 lour was entirely removed* Yellowish-red flocks 

 were thrown down, which being washed, dried, 

 and weighed, amounted to 2 grains. Being dis- 

 solved in muriatic acid, and mixed with prussiate 

 of potash, the whole was iprecipitated in the state 

 of Prussian blue. Hence it consisted of red oxide 

 of iron. But 2 grains of red oxide of iron, are 

 equivalent to 1.37 grain of iron. 



Thus it appears, that the constituents of the ore 

 were as follows : 



Lead, 



50.039 



Copper, 



32.500 



Iron, 



1.S70 



Sulphur, 



11.328 



Loss, 



4.743 





100.000 



If we conceive the loss in the preceding an- 

 alysis to have been sulphur, which I think pro- 

 bable from the violent action of the first portion 

 of nitric acid, the ore was nothing else than a 

 mixture or combination of the sulphurets of 

 lead, copper, and iron, in the following propor- 

 tions : 



