316 ANNUAL KEPORT SMITHSONIAN INSTITUTION, 19 3 9 



US to keep supplies ahead of needs, but they afford us no assurance 

 that the same record can be maintained indefinitely. 



In this connection it is of interest to call attention to some of the 

 concrete accomplishments of recent years. The recovery of gasoline 

 from a barrel of oil has more than trebled in the last 40 years — from 

 about 51/2 gallons in 1899 to about I81/2 gallons in 1937. In the 15- 

 year period from 1922 to the end of 1936 the geologist and the petro- 

 leum engineer have aided the driller in the addition of 10.8 billion 

 barrels to our petroleum reserves, despite the production of 12.8 

 billion barrels during that period. Also, from 1920 to the end of 

 1936 the chemist, by the introduction and improvement of cracking 

 processes, has conserved 8.5 billion barrels of crude oil (20). The 

 petroleum engineer is meeting energetically the challenge to recover 

 the 65 to 85 percent of oil remaining in the ground after a field no 

 longer yields oil by the older methods of production. Each year 

 witnesses the improvement and extension of recovery methods, such 

 as acid treatment and repressuring by the introduction of gas, air, and 

 water into the oil-bearing zones. The increased adoption and refine- 

 ment of such methods in areas where geologic and other conditions 

 permit their use wiU lead to the recovery in places of 50 percent or 

 more of the total oil content of the producing zone. 



Moreover, when a shortage of domestic crude petroleum arrives 

 and there is a consequent rise in prices of petroleum products, substi- 

 tutes will be drawn upon just as they are now drawn upon to some 

 extent in some countries that are supplied with little or no oil re- 

 sources. Some of these substitutes are oil products from coal and 

 oil shale, alcohol from farm products, and gases from wood. Our 

 future resources of coal and oil shale have been so determined by 

 geologic evidence and exploration that we know their approximate 

 extent and quantity. According to Dean E. Winchester (24), the 

 oil-shale deposits of the United States will yield 92,144,935,000 barrels 

 of oil, if and when the price of oil permits. Should coal be called 

 upon to supply the demands now met by oil and gas, the coal reserves 

 of the United States would, according to independent estimates by 

 T. A. Hendricks* and Arno C. Fieldner (6), last about 2,000 years. 

 These two estimates are based on the assumption that the consump- 

 tion of energy from mineral fuels will equal the maximum rate of 

 consumption in the past (approximately 23,400 trillion B. t. u. in 

 1929) and also are based on the assumption of a 30 percent loss of 

 coal in mining. Concerning the cost of motor fuel substitutes. Doc- 

 tor Fieldner (6) comments as follows: 



Keliable information on the cost of making gasoline from coal in British and 

 German plants is not available, but it is believed that it is three or four times 



* Personal communication. 



