236 BULLETIN 42, UNITED STATES NATIONAL MUSEUM. 



Albertite is a variety of solid bitumea which is regarded as being 

 dried and oxygenated petroleum of the following general composition : 



Per cent. 



Carbon 86.04 



Hydrogen 8.96 



Oxygen 1.97 



Nitrogen 2.93 



Ash 0.10 



It was formerly used for the distillation of oils for illuminating pur-, 

 poses, but since the discovery of petroleum it has ceased to be valuable 

 for that purpose. It is illustrated by a single specimen : 



(1) Albertite. New Brunswick, Canada. (59935.) 



Uintite is a variety of bitumen having the following composition : 



Specific gravity 



Carbon 



Hydrogen 



Nitrogen 



Oxygen 



Ash 



Analysis 



100. 00 

 Fristoe &. Lawver. 



It is illustrated by a single specimen : 



(1) Uintite. Uintah, Weber County, Utah. (.59471.) 



LIQTTID BITUMEN. 



PETROLEUM. 



Composition : A mixture of various hydrocarbons of the marsh-gas 

 and ethylene series and the parafflus. 



It varies in specific gravity from 0.92 to 0.75. It is generally liquid, 

 but hardens on exposure to the air, generally on account of oxidation, 

 to semi-solid or even solid asphalt. It also thickens upon exposure to 

 cold. Petroleum varies in color from black through many shades of 

 brown, green, and red, to very light yellow. 



The most generally accepted theory of the origin of petroleum is 

 that it has resulted from the decomposition of animal and vegetable 

 matter. It is found in rocks of all ages, from the oldest to the youngest, 

 wherever circumstances have favored its collection and storage by nat- 

 ural agencies. It geuerally collects in an open, porous rock, sandstone 

 or limestone, below an impervious cover of shale or slate. Small 

 amounts of petroleum have been used for ages in medicine, particularly 

 as a liniment. By far the largest amount is used for the preparation 

 of illuminating oils, in which operation a considerable number of 

 other valuable products are also formed. Where it is abundant and 

 cheap it has also been used as a fuel. 



Petroleum has been produced in large amounts in the United States 



