ON THE SOURCES OF ENERGY IN 



NATURE AVAILABLE TO MAN 



FOR THE PRODUCTION OF 



MECHANICAL EFFECT. 



[From Presidential Address to the Mathematical and 

 Physical Section of the British Association, Yor/c, 1881.] 



DURING the fifty years' life of the British Associa- 

 tion, the Advancement of Science for which it 

 has lived and worked so well, has not been more 

 marked in any department than in one which 

 belongs very decidedly to the Mathematical and 

 Physical Section the science of Energy. The 

 very name energy, though first used in its present 

 sense by Dr. Thomas Young about the beginning 

 of this century, has only come into use practically 

 after the doctrine which defines it had, during 

 the first half of the British Association's life, 

 been raised from a mere formula of mathematical 

 VOL. II. F F 



