FUEL FOR GAS TRACTORS 119 



if the weight in pounds per gallon is known at a temperature 

 of 60 F.: 



(Weight in Ibs. per gal. X 12 ) -5- 100 = specific gravity 

 (140 -T- specific gravity) 130 - degrees Baume 



For example: Common engine kerosene weighs about 6.7 

 Ibs. per United States gallon. Applying the first formula is 

 equivalent to dividing by the weight of water, and gives a 

 specific gravity of .804. 140 -+ .804=174H-130=44 , the 

 Baume gravity. 



The crude oils from different districts vary widely in their 

 weight and composition. Those from the Appalachian dis- 

 trict have a paraffin base, while those from the Southwest and 

 California have largely an asphalt base. The two latter 

 yield a much lower percentage of the lighter oils, such as com- 

 mercial gasoline or naphtha, and a larger quantity of the 

 heavy fuel oils, lubricants, wax, and solid waste. The differ- 

 ence in weight of crude oils is shown in the following table of 

 Baume gravities: 



DISTRICT DEGREES - BAUME 



Pennsylvania 42 to 50 



West Virginia, Kentucky 40 to 46 



Ohio, Indiana 37 to 40 



Illinois 30 to 34 



Kansas, Oklahoma, Louisiana 22 to 32 



Texas 16 to 26 



California 12 to 28 



Though crude oil and its products vary in weight per gallon, 

 they are remarkably uniform in heat value for a given weight. 

 American crude oils range from 18,000 to 22,000 B.t.u. per 

 pound, an analysis of fifteen from various sources averaging 

 20,400. A conservative estimate will place commerical gaso- 

 line and kerosene at 20,000 B.t.u. per pound. 



The world's first systematic boring for oil occurred when 

 the Pennsylvania field was opened in 1859, and, until the 

 rapid introduction of the gasoline engine made greater produc- 



