258 



ANNUAL REPORT SMITHSONIAN INSTITUTION. 1950 



kiiow also that before the end of the eighteenth century the employ- 

 ment of this new source of energy had reached such magnitude as to 

 produce the major social and economic disturbances in Britain referred 

 to as the "Industrial Eevolution." 



By 1864 (1, 2),' from which date annual world-production statis- 

 tics are available, the production of coal in the w^orld (fig. 1) had 



WORLD PRODUCTION OF COAL 



1660 1880 



Time (Yeors) 

 FiGUBE 1. 



reached about 180 million metric tons a year, and from that date until 

 1914, when it had reached a rate of 1,300 million tons a year, it con- 

 tinued to increase geometrically at a rate of 4 percent a year, or at a 

 rate such that the annual production was doubling every IT years. 



The length of time during which coal has been mined is likely to 

 be misleading. To appreciate the magnitude of what is happening 

 and the brevity of time during which most of it has occurred, consider 

 these facts : By the end of 1947 the cumulative production of coal dur- 

 ing all past human history amounted to approximately 81 billion 

 metric tons. Of this, 40 billions, or approximately one-half, have been 

 mined and consumed since 1920. Sixty-two billions, or more than 

 three-quarters, have been produced since 1900 — during our lifetime. 



s Numbers in parentheses refer to bibliography at the end of the paper 



