THE NONMETALLIC MINERALS. 445 



These underlaid by soft sands and shales. The analyses given below 

 are of interest as showing percentage of bituminous matter in samples 

 from various localities. 



San Luis Obispo Bituminous Rock Company' 's mine. 



Sand 6. 83 



Clay 3. 36 



Lime 2. 81 



Asphaltum 87.00 



Waldorf Mine, Santa Barbara County. 



Bitumen 76. 2 



Moisture 1.8. 



Mineral residue 22. 



100.0 

 Punta Gorda Mine, Ventura County. 



Bitumen 28. 53 



Silica 51. 64 



Clay 4. 76 



Sulphate of lime 2. 45 



Carbonate of lime 11. 96 



Carbonate of magnesia 55 



99.89 



Uses. The uses of the common type of material such as is known 

 simply as asphalt are quite varied. The walls of Babylon are stated 

 to have been cemented with it, and doubtless it was so used in other 

 ancient cities. It was also, as at present, used for making vessels 

 water-tight. At the present day the refined asphalts are used, accord- 

 ing to F. V. Greene, 1 as a varnish or paint, as an insulating material, 

 for waterproofing, as a cement in ordinary construction, and as a 

 cement in roofing and paving compounds. For these purposes it is 

 first tempered with some form of oil, the kind and amount used 

 depending on the purposes to which it is to be applied. A mixture of 

 asphalt and sand forms the ordinary concrete for sidewalks and base- 

 ment floors. The most extensive use of asphaltic compounds is at 

 present for street pavements, the material for this purpose being mixed 

 with fine sand and sometimes powdered limestone. The asphaltic 

 sands, sandstones, and limestones are sometimes so evenly impregnated 

 with bituminous matter that they may be crushed and applied directly 

 to the roadbed. The uses to which are put the higher grades of 

 asphaltic compounds, such as are designated by special names, are 

 given further on. 



MANJAK. The local name of manjak is applied to a variety of bitu- 

 men somewhat resembling uintaite, occurring on the island of Barbados, 



1 Asphalt and its Uses, Transactions of the American Institute of Mining Engineers, 

 XVII, 1889, p. 335. 



