VI BULLETIN 42, UNITED STATES NATIONAL MUSEUM, 



Page. 

 Silver — Contiuued. 



Processes of extracting silver 26 



Roasting milling 26 



Ontario Mill 27 



MoultonMill 30 



Compound process 31 



Ziervogel process 31 



Boston and Colorado Smelting Works 32 



Lead: 



Lead minerals 36 



Galena 36 



Anglesite 37 



Cerussite 37 



Silver-lead ores 38 



Silver-lead smelting 41 



Colorado Smelter 43 



Retiniug base bnllion 54 



Cheltenham Smelting and Refining ^Vorks 55 



Kansas City Smelting and Refining Works 55 



Lead ores 57 



Southeastern Missouri Lead Region 57 



St. Joe Lead Works : 62 



Desloge Lead Works 64 



Compound process 67 



Pig lead and white lead at Lone Elm Works 67 



Application of lead ■ 72 



White lead. Dutch process 72 



Copper: 



Copper minerals 73 



Copper 73 



Chalcopyrite 74 



Bornite 74 



Chalcocite 75 



Cuprite 75 



Chrysocola 75 



Malachite 76 



Azurite 76 



Copper ores 77 



Lake Superior Region 77 



Central Mine 79 



Osceola Mine 81 



Osceola Mill 87 



Delaware Mine 93 



Delaware Mill 96 



Smelting Lake Superior copper 97 



C. G. Hussey Works 97 



Lake Superior Native Copper Works 98 



Copper smelting 98 



Vermont Copper Mining Company 99 



Ducktown Copper Works 100 



Ste. Genevieve Copper Works 101 



Schuylkill Copper Works 103 



Orford Copper and Sulphur Works 1 05 



Butte Copper district 105 



Montana Smelter 106 



