644 



GEOLOGY AND MINING INDUSTRY OF LEADVILLE. 



friable masses, composed of iudistiuct and exceediugly small crystals, with a uuiform 

 grayish tiuge. The specimen analyzed was found at Grant smelter, where a large 

 quantity of it is used. 



Analyses X, XI, and XII. Dolomites. 

 Elementary. 



Carbonic acid 



Cliloiine 



Sulphur 



Sulphuric acid 



Phoeplioric acid 



Sodium 



Potassium 



Magnesium 



Calcium 



Lime 



Magnesia 



Protoxide of manganese . 



Protoxide of iron 



Pi'Otoxide of lead 



Peioside of iron 



Silica 



Alumina 



Organic matter 



Water 



Loss 



Analysis X 

 (Dugan). 



Total . 



46. 9262 

 0.1429 

 Trace 

 None 

 0. 1224 

 0. 0697 

 0. 0386 

 Trace 

 Tiace 

 30. 4297 

 20. 7843 

 0. 0533 

 0. 3827 

 Trace 

 0. 1062 

 0. 7064 

 0. 1673 

 0. 0250 

 0. 0440 

 0. 0013 



100. 0000 



Analysis XI 

 (Montgomery). 



43. 7917 

 0. 0618 

 Tiace 

 Trace 

 0. 0076 

 0. 0273 

 0. 0151 

 Trace 

 Trace 

 27. 2586 

 20. 0455 

 0. 0620 

 0. 5742 

 Faint trace 

 0. 0974 

 7. 7652 

 0. 1068 

 0. 0670 

 0. 0550 

 0. 0012 



100. 0000 



Analysis XII 

 (Glass- Pendery). 



47. 3922 

 0. 0408 

 None 

 None 

 0. 0328 

 0. 0119 

 0.0110 

 Trace 

 Trace 

 29. 9671 

 21. 5230 

 0. 1998 

 0. 1275 

 None 

 0. 2232 

 0. 2748 

 0. 0400 

 0. 0152 

 0. 0707 

 0. 0700 



Discussion. — The dolomites used iu smelting are true dolomites, iu which small 

 quantities of carbonate of lime and magnesia are replaced by carbonates of manganese 

 and iron. The presence of chlorides was at first puzzling, for the reason that about 

 half the total quantity of chloride was soluble in boiling water when the dolomites 



