352 CONTRIBUTIONS TO ECONOMIC GEOLOGY, 1902. [bull. 213. 
that with any refining process now in use the yield of illuminants is 
small and the quality poor. 
It is as a fuel that the Coastal Plain oil has thus far been chiefly 
utilized, and this will probably continue to be its principal use in the 
future. Tested in various forms of calorimeter, this oil is shown to 
have practically the same heating value as Pennsylvania petroleum, 
which is regarded as the standard liquid fuel. Practical tests in 
steam raising have been made with the Texas oil, and it has been 
found to have an evaporative power of 15.29 to 15.55 pounds of water 
per pound of oil used. Of the steam generated 3.1 to 4.8 percent 
was used by the burner in sprajing the oil. There was thus left 
available for use the steam from 14.74 to 15.16 pounds of water per 
pound of oil used. In ordinary practice, without the use of special 
precautions to guard against waste, 13 pounds of water should be 
evaporated by 1 pound of Texas oil, as compared with 6 to 6.5 pounds 
by the bituminous coals of Indian Territory, 8.7 pounds by Pittsburg 
coal, and 9 by Pennsylvania anthracite. From these relative fuel 
values it appears that 3.1 barrels of Texas oil may be regarded as 
having the same fuel value as 1 ton (2,000 pounds) of Southwestern 
bituminous coal and 4.31 barrels of oil as 1 ton of Pittsburg coal. 
It should be noted, however, that the conditions under which coal 
and petroleum are used in ordinary practice favor the obtaining of a 
larger per cent of the theoretical fuel value in the petroleum than in 
the coal. Also a deduction of at least 10 per cent should ordinarily 
be made from the fuel cost of petroleum on account of the economy 
in handling the liquid fuel as compared with coal. 
As a locomotive fuel petroleum has many additional advantages 
over coal. Practical tests have shown that its use may add as much 
as 30 per cent to the efficiency of the boiler, while it weighs only 07 
per cent as much as coal having the same heating capacity. From 
these tests it appears that with coal at $3 per ton petroleum should 
be worth 97 cents per barrel as a locomotive fuel. 
