120 



POWER AND THE PLOW 



tion necessary, this and the adjoining states supplied the great 

 bulk of the petroleum refined in America. A work published 

 prior to 1899 gives the following results from fractional distil- 

 lation of a Pennsylvania petroleum having .80 specific (45 B.) 

 gravity. The Baume gravity is added by the formula quoted. 

 It represents roughly the classification of petroleum products 

 at that time: 



The products lighter than lamp oil comprised only about 16 

 per cent, of the total and showed a much wider range in gravity 

 than kerosene. 



The mid-continent and Western oil fields were opened 

 at a much later date. They are now producing oil in abundance, 

 but yield even a lower proportion of the lighter oils. The 

 following recently compiled percentage analysis of a typical 

 California crude illustrates the difference in character of 

 supply: 



Naphtha, gasoline, benzine, etc., 2.8; commercial "distillate," 

 23.1; kerosene, 14.4; lubricants, 34.1; wax or asphalt, 21.4; 

 residue and waste, 4.2. 



Many of the former grades have now been abandoned and 



