PHYSIOGRAPHY. 59 



Bismuth-Ochre Bitumen. 

 Soft. Sp. gr.=4-36. 



1. Upon charcoal, it is easily reduced to the metallic state, attended 

 y a peculiar odor. It is soluble in nitric acid, the solution throwing 

 3wn a white precipitate on the addition of water. 



2. Analysis. 



Oxygen 10-13 



Bismuth 89-87 



It frequently occurs mixed with carbonate of bismuth and iron. 

 3. It is found in small quantity upon the ores of bismuth, cobalt and 

 .ickel, at Schneeberg in Saxony, Joachimsthal in Bohemia, Saint Agnes 

 i Cornwall, Siberia ; and at Haddam, (Con.) in the chrysoberyl rock, 

 vhere it is sometimes accompanied by Bismuthine. 



BITTER-SPAR. (See Dolomite.) 

 3ITUMEN. Black Mi n era 1- Resin. MOHS. 



Aggregation solid or fluid, and all the intermediate sta- 

 ges. No regular form. Stalactilic shapes: surface smooth. 

 Massive. 



Fracture conchoidal, more or less perfect, uneven. 



Lustre resinous. Color black, passing into various brown 

 Hid red tints. Fluid varieties are sometimes perfectly col- 

 orless. Streak commonly unchanged, sometimes lighter 

 than the color. Translucent on the edges, opake ; some 

 fluid varieties are transparent. 



Sectile, malleable, elastic. Bituminous odor. Hard- 

 ness = 0-0 . . . 2-0. Sp. gr. = 0-S2S, brown, malleable ; 

 1-073, black, slaggy ; 1*160, hyacinth-red, slaggy. 



1. Mineral Oil and Mineral Pitch have been treated as two species; 

 the former embracing under it as varieties Naphtha and Petroleum, and 

 the latter Earthy Bitumen, Elastic Bitumen, and Compact Bitumen or 

 Asphaltum ; but all these varieties differ in nothing except their state of 

 aggregation, which, however, forms an uninterrupted series from those 

 which are perfectly fluid to such as are perfectly solid. The Mineral 



