184 SUPER-ORGANIC EVOLUTION 



and therefore the progress of the physico-chemical 

 sciences has been necessary for man to increase or 

 enlarge his senses, which he has attained, in the 

 matter of sight, by the use of the microscope and 

 by spectral analysis, which allow him to extend 

 his knowledge of things from the infinitely little to 

 the infinitely great. 



The thermo-electric pile enables man to appreciate 

 changes of temperature that appear unlikely ; add 

 the searching powers of chemistry, which is capable 

 of perceiving and discovering substances even in 

 infinitesimal quantities. One must consider all 

 these resources as extensions of man's senses, 

 thanks to which he has found means of gathering 

 all these energies in order to marshal and exploit 

 them, and which, from their being beyond his 

 sphere of action, seemed foreign to human intelli- 

 gence. Who supposed some years ago that, among 

 the multitude of rhythms that exist in the atmo- 

 sphere, there was one of which man would one day 

 avail himself in order to transmit his thoughts to a 

 distance? If this is now only the beginning of 

 new discoveries, what will be the limit of human 

 progress ? 



Whilst man had no means of observation beyond 

 his own senses, the world for him was very limited, 

 and his intelligence, that counted upon no further 

 resources, was also restricted. The instruments of 



