PROBLEMS OF MODERN SCIENCE 



between the masses involved in any chemical 

 reaction, but in practice the amount of energy 

 interchange in chemical reactions is of a lower 

 order of magnitude, and can be disregarded. 

 In concluding, there is one other interesting 

 application of these ideas which I should like to 

 mention. It is now very probable that in the 

 evolution of the older stars from the nebulas the 

 heavier elements are continuously being formed, 

 in some manner which we do not yet understand, 

 from the lighter ones such as hydrogen or helium. 

 These processes should be expected to furnish an 

 enormous amount of heat, far greater than that 

 which can arise from the Helmholtz theory of 

 mutual gravitation of the contracting parts. By 

 these considerations the duration of the existence 

 of the heavenly bodies is enormously increased 

 over that given when gravitation is regarded as the 

 source of their energy. 



O. W. RICHARDSON 



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