16 THE FITNESS OF THE ENVIRONMENT 



made of thermodynamics (the department of 

 science which is especially concerned with 

 the laws of energy transformation) a sub- 

 ject which few who cultivate the physical 

 sciences may disregard. Countless develop- 

 ments and achievements of thermodynamics 

 give very real ground for the belief that we 

 may speculate about the transformations of 

 energy in the universe with the same assur- 

 ance that we have in discussing chemical 

 changes. 



Our reasons for confidence in the truth of 

 current general notions of energy, and in 

 their adequacy to account for any phenomena 

 so far as energy is concerned, wherever life 

 exists in the universe, are manifold, and not 

 unlike those which have been reviewed in dis- 

 cussing the elements. 



Centuries of search have revealed, in addi- 

 tion to that most obvious form which is 

 studied in dynamics, a very small number of 

 varieties or manifestations of energy, such as 

 heat, electricity, magnetism, optical energy, 

 and chemical energy. Such manifestations 

 of energy are by no means confined to the 

 earth or to the solar system. Indeed Newton 

 first worked out the general laws of dynamics 

 and erected them into a complete science 

 with the *\id, not of terrestrial, but of astro- 



