FUEL FOR GAS TRACTORS 123 



percentage of kerosene. Where Pennsylvania oils formerly 

 yielded as high as 16 per cent, of gasoline, benzine, and naphtha, 

 they now yield less than 10 per cent., and the Appalachian 

 district, which includes the surrounding states, yields now only 

 about 15 per cent, of the total supply of crude oil. The Illinois, 

 the mid-continent fields, Texas and California, now yield 

 from nine to thirteen gallons of kerosene and so-called engine 

 distillate to each one of gasoline where distillation is complete. 

 Furthermore, the commercial gasoline is much less volatile, 

 having been lowered from 76 to 60 B., in about fifteen years. 

 The percentage of gasoline of the former quality from 

 the present heavy-producing districts would be practically 

 negligible. 



The shift of the centre of production has been no less rapid 

 than the invention of apparatus for using the more volatile 

 hydrocarbons. The gasoline stove taught the people the use 

 of gasoline, and during the last two decades the development 

 of the gas engine for automobile, stationary, traction, marine, 

 and commercial purposes has increased the demand by leaps 

 and bounds. The domestic consumption of gasoline has in- 

 creased from 14,000,000 gallons in 1905 to 50,000,000 gallons 

 in 1910. A surplus of kerosene is being refined simply to 

 furnish an adequate supply of gasoline, even though much 

 of the crude oil at the present time is merely skimmed i.e., 

 the gasoline is taken out to supply the present demand, and 

 the rest, including the kerosene, either stored or used for 

 fuel under steam boilers. 



The use of the kerosene lamp is now all but confined to 

 rural districts. In many large sections of the country the 

 consumption of kerosene for all purposes is less than that of 

 gasoline. The tail wags the dog. Gasoline, formerly a by- 

 product of illuminating-oil refining, is now the only petroleum 

 product which taxes the capacity of the refineries. Refiners 

 have stored kerosene to the limit of their tank capacity, and 

 from every source comes the information that unusual methods 



