THE FOUNDATION OF EVOLUTION 



matter, let us look at it as shown in radium. Let 

 us also premise that the disintegration or evolution 

 theory of the radium atom has lately been accept- 

 ed by its one outstanding opponent, Lord Kelvin, 

 who may probably be regarded as the greatest 

 physicist of any age. With his conversion to it 

 the theory now to be presented in outline may be 

 said to be established. 



An atom of radium and the atoms of all the 

 other so-called elements differ only in detail 

 consists of a large number (probably hundreds of 

 thousands) of incredibly minute bodies known as 

 electrons. These are in rapid motion, describing 

 orbits, as is believed, around some central point. 

 So small are the electrons that the distances be- 

 tween them are relatively as great as those between 

 the planets of the solar system. In size they are 

 to the atom "as a full stop to a cathedral." But 

 even when we substitute for the simple conception 

 of an atom entertained by Democritus or Newton 

 or Dalton that of a minute, hard speck such a 

 conception as modern physics entertains, we do 

 not necessarily impugn its stability. Such a com- 

 plex atom, microcosm though it be, might con- 

 ceivably be conserved, permanent, indestructible. 

 But far more remarkable than our recent discovery 

 of the complexity of the atom is the discovery 

 that it is only a stage in all-embracing evolution. 

 All the phenomena of radio-activity the pro- 

 duction of heat and light and electrical disturb- 

 ances are due to the fact that these atoms of 

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