60 BULLETIN 42, UNITED STATES NATIONAL MUSEUM. 



Boasted sulphides. 



Iron (Fe) 



Lead (Pb) 



Copper (Cu) 



Nickel and Cobalt (Ni and Co) . 



Lime (CaO) 



Magnesia (MgO) 



Sulphur (S) 



Insoluble residue 



Analyst. 



Desloge. 



Per cent. 

 17.39 



15.12 



Monell. 



Per cent. 

 16.63 

 15.42 



34.18 

 17.83 

 6.36 



Setz. 



St. Joe. 



Per cent. 

 23.82 

 18.46 



Setz. 



Per cent. 

 21.91 

 30.74 



0.98 

 16.25 

 8.11 

 8.96 



Mine La Motte. 



Setz. 



Per cent. 

 44.37 

 12.58 

 0.97 

 4.07 

 3.57 

 1.25 

 7.12 



NeUl. 



Neill. 



The roasted ores are reduced iu a cupola furnace. There are two 

 kinds of smelting. In the first puddle mill cinder is employed as an 

 iron flux, and pig lead, first matte, and slag are produced. In the sec- 

 ond class of smelting roasted matte is used for the iron flux, and at the 

 same time mattes richer iu cobalt and nickel and copper are produced. 

 This concentrating of the matte is continued until it contains sufticient 

 cobalt and nickel to be shipped away for the smelting and refining of 

 these metals. 



The charge of the furnace is generally calculated to give a slag con- 

 taining 30 per cent, silica, 40 j^er cent, protoxide of iron, 20 per cent, 

 oxide of calcium, and 10 per cent, of other constituents, but these vary 

 a little. SufiBcient iron is also added to form matte with the sulphur of 

 the ore. 



The slags produced at the different works and in the dift'erent char- 

 acters of smelting are represented by the following analyses : 



Ore slag. 



Silica (SiOj) 



Alumina ( AI2O3) 



Protoxide of iron (FeO) 



Lime (CaO) 



Magnesia (MgO) 



Lead (Pb) 



Per cent. 

 35. 30 



.5.50 

 35. 90 

 13.90 



9.27 



