Analysis of Ores from North Carolina. 349 



consist of carbonate of lead, as far as it concerns the valuable 

 portion of the formation. Besides this we have also zinc, cop- 

 per, silver, iron, manganese, silica, alumina, and magnesia ; the 

 two former, and sometimes the lead, being in the state of sulphu- 

 rets as well as carbonates, the silver being metallic, rarely sul- 

 phuretted, and the iron and manganese as oxides, constituting 

 with silica, alumina, and magnesia, the gangue. 



The object being to ascertain the relative amounts of the me- 

 tals and the constituents of the gangue, the analysis was con- 

 ducted by simple solution in nitric acid, of all soluble materials, 

 and then by igniting the insoluble with carbonate of soda and 

 treating it as a silicate. As we did not endeavor to ascertain the 

 exact manner of combination in each specimen, the sum of the 

 substances will necessarily vary from one hundred, which, how- 

 ever, has no influence on the general results. 



No. 1, analyzed by E. Mayer, a selected specimen from the 

 best portion of the vein, containing masses of solid silver dissem- 

 inated through it, independently of small spangles barely visible 

 to the eye, and that contained in the carbonate of lead. 



Per cent, of metals. 



Metallic silver. 

 Carbonate of lead, 

 Sulphuret of zinc, 

 r Peroxide of iron, 

 ^'o " manganese, 



S ^\ Silica, 

 g I I Alumina, . . 

 L Magnesia, . 



101.35 

 No. 2. By J. V. Z. Blaney. Bluish grey, very talcose, contain- 

 ing a few masses of silver ; the greater part of the metal being 

 in the form of minute spangles, particularly in the dark bluish 

 portions of the ore, and becoming visible only when rubbed by 

 a hard and smooth substance on a white surface. 



Silver, 



Carbonate of lead, 

 ** copper, 



^ f Oxide of iron, 

 ^\ Silica, 

 i Ahi 



c j Alumina, 

 O I Magnesia, . 



99.28 



