THE LESSON OF EVOLUTION 



CHAPTEE I 



PHYSICAL EVOLUTION 



THE idea of evolution originated with the Greeks, 

 but only as a speculation which led to nothing ; and 

 its scientific history may be said to commence in the 

 early part of the last century, when the practically 

 new theory of the origin of species by gradual 

 development was proposed by Lamarck. This 

 theory was at first discredited for lack of evidence ; 

 but it was developed and demonstrated by C. Darwin 

 in the middle of the century. About the same time 

 it was pointed out by Lord Kelvin 2 that not only was 

 the sun cooling, but that all kinds of energy, when 

 converted into heat, lost a portion by radiation into 

 space, and that this process must go on until the 

 whole Universe was of a uniform temperature. So 

 that, although the amount of energy in the Universe 

 remains unalterable, it will, by redistribution, be 

 brought into the potential state, and thus, when 



z Pro. Eoy. Soc. of Edinburgh for April 19th, 1852, and 

 Phil. Mag.. October, 1852, p. 304. 



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