48 BULLETIN 42, UNITED STATES NATIONAL MUSEUM. 



silver. Fryer Hill, LeadviUe, Lake County, Colorado. (51054.) A typical analysis 



of this IS as follows: 



,-, , 36. 44 per cent 



Iron (Fe) -.^ an * 



,,,,,. 16. 99 per cent. 



Manganese (Mn) o -^ 



c-,- /c.-r» -v 8. 76 per cent. 



Silica (SiOi) , 



T 1 /D» \ none, by assay. 



Lead (Pb) ^^ „ ^ 



Sliver (Ag) 8. to 10. ounces per ton. 



A single illustration of limestone, used for flux, from Pueblo, Colorado, 



is shown. (51046.) 



A typical analysis of the limestone is as follows : ^^^ ^^^^ 



^. ,„ ^, 52.34 



Lime (CaO) ^^^ 



Carbonic acid (CO2) ' " 



Sesquioxide of iron (Fe.iOs) and alumina (AljOj) • 



Silica (SiO,) ^-^ 



Three samples of roasted ores are shown, one to represent each 

 character of roasting practiced. 



(1) Roasted ore, the lump ore from the Colonel Sellers Mine, Leadville, Lake 

 County, Colorado, represented by specimen No. 51072, after having been roasted lu 

 the roasting stalls. (51045). A typical analysis is as follows : ^^^^ ^^^^ 



Oxide of lead (PbO) ^^-'^^ 



Oxide of zinc (ZnO) 28 SC 



Sesquioxide of iron (FcjOg) ' ^ 



Protosesquioxide of manganese (Mn:,04) 



Alumina (AI3O3) .' 



Lime (CaO) [-1*1 



Silica f Si O:) '■ -- ^-^^ 



Sulphur (S) mostly present as sulphuric anhydride (SO3) ,. 



Silver (Ag) 45.4 ounces per ton ^- ^^^ 



(2) Roasted ore, the concentrated ore from the Colonel Sellers Mine, LeadviUe, 

 Lake County, Colorado, represented by specimen, No. 51075, after having been 

 roasted in the reverberatory furuace. (51076. ) A typical analysis is as follows : 



Per ceot. 



Oxide of lead (PbO) ^^•''f 



Oxide of zinc (ZnO) f-^^^ 



Sesquioxide of iron (FejOs) ^''^''^'^ 



Protosesquioxide of manganese (Mn304) "• "•* 



Lime (CaO)..-. ^-^^ 



Magnesia (MgO) " ' 



Alumina (AI2O3) " 



Oxide of copper (CuO) ^'^^ 



Silica (SiO:) "• *-^: 



Sulphuric anhydride (SO3) '*• ""^^ StotalS.2.62 



Sulphur cS) J^-^y 



Silver (Ag) 42.5 ounces per ton "• ^''" 



(3) Fused ore, the result of roasting the flue dust from the shaft furnaces, mixed 

 with siliceous sulphureted ores, in the fusion furnace. Locally known as gray slag. 



(51050.) The analysis is as follows: 



^ ' Per cell!. 



'20 "1 

 Oxide of lead (PbO) ~'^-^ 



Sesquioxide of iron ( Fe.^O:)) _, 



Sesquioxide of manganese (MuiOa) " 



Alumina (AI2O3) • 



