PETROLEUM RESOURCES ARNOLD. 287 



Comparing the writer's estimates with those of Dr. Day, it is at 

 once apparent that the estimates for the older eastern fields have 

 been reduced while those for the western fields have been increased. 

 This is especially true for the Mid-Continent field, in which there 

 w as little development at the time Dr. Day's figures were compiled. 

 In the case of California ^ it has been found that the available satura- 

 tion is less than was expected during the early history of the field. 

 At the time the first estimates were made the field gas pressure was 

 high and water trouble had not become serious. With the lapse of 

 time it has become evident that a reduced gas pressure and water infil- 

 tration necessitate materially cutting the original figures. 



At the present rate of consumption of approximately 265,000,000 

 barrels per year, an estimated supply of 5,763,100,000 bam-els would 

 last only, approximately, 22 years. However, as the total produc- 

 tion of the United States w^ill gradually decrease from year to year, 

 it is believed that the total available supply will spread out over a 

 period of from 50 to 75 years. The price of oil, which now ranges 

 from 40 cents to $2 per barrel (average, 95 cents), depending on the 

 locality and grade of the product, probably will increase to figures 

 approximating $1 per barrel for fuel oil and possibly $5 or more for 

 the lighter grades. All other factors being equal, a barrel of fuel 

 oil as compared with coal on the Pacific coast is worth to-day 

 93 cents. Even were oil to be used only as a fuel, the tendency would 

 be for it to rise in price until it reached a point set by the value of 

 coal in the same regions. As oil has so many points in its favor, as 

 regards ease of handling, cleanliness, etc., it is quite evident that 

 eventually it will be sold at a higher price than is warranted by its 

 heat value as compared wnth that of coal. 



Before the fi'ee natural petroleum in the earth is exhausted the 

 oil shales of Colorado, Utah, California, and other States will have 

 begun to be utilized as a source of petroleum. Also artificial oil 

 made from animal and vegetable waste probably will be available to 

 take its plac^. Even at the present time the necessities of w^ar have 

 led certain of the European governments to utilize various substi- 

 tutes for petroleum and its derivatives, the substitutes in general 

 being made from organic substances. 



In conclusion, the writer might repeat what often has been pointed 

 out by conservationists, that oil as far as possible should be used for 

 those purposes for wdiich we have no other substitute, namely, for 

 lubricants, refined derivatives, etc., and not for fuel. If used for 

 fuel, it should not be in connection with the wasteful steam engine, 

 but in the Diesel engine and similar types, which are so much more 

 efficient that their use doubtless will become more and more general 

 as time goes on. 



1 Dr. Geo. Otis Smith discusses the duration of California petroleum resources la Mln. 

 Res. U. S. for 1910, Pt. IT, p. 416, et seq. 



