ASPHALTUM AND BITUMINOUS ROCK. 



BY JOSEPH STRUTHERS. 



[Joseph Struthors, minoralogist ; bom at New York city in 1865, and attended 

 the School of Mines, C'ohiinbiu college; (now Columbia university), graduating in 

 the course of chcnii.stry in 1885; for fifteen years after his graduation he was on the 

 staff of instructors of the department of metallurgy at Columbia university ; organ- 

 ized and conducted the first summer school in practical metallurgy of Columbia 

 university (1S96), which was at Butte, Mont. Dr. Struthers has visited many 

 metallurgical plants in the United States and Europe, and he has carried on special 

 metallurgical investigations; he has written numerous articles for the Engineering 

 and Mining Journal, Mineral Resources of the United States, Twelfth Census of the 

 United States and School of Mines Quarterly, and is assistant editor of the Transac- 

 tions of the American Institute of Mining Engineers; appointed Field Assistant to 

 the United States Geological Survey for 1901 and 1902, and in May, 1903, special 

 agent for the United States census.] 



Asphaltum is the name applied to different forms of bitu- 

 men. Its composition varies, and it is known by many other 

 names, bestowed on account of some special characteristics 

 resulting from its composition or the locality from which it 

 has been obtained. The most common of these names are: 

 Natural mineral pitch, Jews' pitch, Trinidad asphalt, Cuban 

 asphalt, Dead sea bitumen, manjak, maltha, brea, chapapote, 

 elaterite, wurtzilite, nigrite, gilsonite, grahamite, and uintaite. 



Asphaltum has been an article of commerce from remote 

 antiquity, the supply having been obtained from the deposits 

 near the Dead sea, where the material floated on the surface 

 or was washed ashore by the waves, the product being known 

 to the Arabs by the name of Hajar Mousa, or Moses's stone. 



In Germany asphaltum was known as early as 1626 xmder 

 the name of harzerde (pitch earth), which was described in 

 1692 by Doctor Amiest as asphaltum. Bituminous limestone 

 is mentioned by Doctor Erynis in several pubhcations prior 

 to 1721. The deposits at Seyssel, France, were discovered 

 in 1802, and the asphaltum interests of France and Switzer- 

 land were united in 1832 by Count de Sassenay. 



Asphaltum ranges in form from the liquid maltha to the 

 hard, solid glance pitch, which gradually merges into asphal- 

 tic coal. The specific gravity of pure asphaltum ranges from 

 1 to 1.3 and the hardness from 2 to 3. The solid varieties 



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