54 ILLINOIS ACADEMY OF SCIENCE. 



total reserve in the earth, and the probable length of time before 

 it will be exhausted. Petroleum serves so many unique func- 

 tions in modern life that it seems indispensable ; but in all prob- 

 ability its exhaustion is a matter of only a few years. It is said 

 that if the present rate of increase in production continues, our 

 known fields will be exhausted in twenty-three years ; and even 

 if the present production continues without increase the known 

 supply will be gone within ninety years. These views are startling, 

 but they are based on the best knowledge of the present time, 

 with reference to the supply and demand at home and abroad. 



PETROLEUM OUTPUT OF THE WORLD. 



Since petroleum is an important element of the world's com- 

 merce, being easily transported by rail or water, the conservation 

 problem at home is influenced by conditions in other producing 

 countries. In 19 lO, thirteen countries produced a total amount 

 exceeding 327 million barrels. The output in the United States 

 equaled 64 per cent of the total ; the Russian production equaled 

 2 1 per cent ; and no other country produced as much as 4 per 

 cent. Thus, the United States is by far the dominant producer 

 in the world. The world's output in each year since 1906 has 

 exceeded that of the previous year by 52, 21, 13, and 29 million 

 barrels, or by an average of 29 million barrels. 



PRODUCTION OF PETROLEUM IN THE UNITED STATES. 



Output and Probable Duration. 



Since the United States is by far the largest producer of petro- 

 leum, the conditions of production in our own country are the 

 most important in connection with conservation. Since 1861, 

 when the production was a little more than two million barrels, 

 the output has doubled repeatedly within the following short 

 yearly intervals: 9, 4, 7, 10, 12, 6. 



The fields' of the United States are shown in Plate I. The 

 phenomenal increase in production is indicated by Plate II, which 

 shows also the year in which new fields influenced the total 

 production. 



In order to know the effect of such increasing production on 

 the duration of supply it is necessary to calculate the probable 

 content of the oil sands in the known fields. The best estimates 

 in 1907 indicated that the original supply was between 10 and 25 

 billion barrels. Calculation showed that the oil would be gone 



