20 Inorganic Evolution 



§11. The Fashioning of the Earth. 



As we have seen, there is among astronomers a gen- 

 eral acceptance of the proposition that our solar 

 system had its origin in a great nebula. 

 As Tennyson wrote : 



They say 

 The solid earth whereon we tread 

 In tracts of fluent heat began, 



And grew to seeming random forms, 



The seeming prey of cyclic storms 

 Till at the last arose the man. 



Or, again, in Psyche's lecture in The Princess: 



This world was once a fluid haze of light, 

 Till toward the center set the starry tides, 

 And eddied into suns, that, wheeling, cast 

 The planets. 



Secondly, the modern theory of the constitution of 

 matter has given vitality to the idea of inorganic 

 evolution. By expelling electrons and protons the 

 atoms of radium may eventually produce lead, and so 

 does thorium, and so does actinium, but the three 

 leads, though identical chemically and spectroscopi- 

 cally, are yet different from one another and from 

 common lead. To a certain extent the transmutation 

 of elements has been observed, and, as we have seen, 

 the different kinds of matter differ not in their stones 

 and mortar (if such static words may be allowed for 

 a moment), but in the numbers, proportions, and 

 positions of the constituent electrons and protons. 

 When we hear of Sir Ernest Rutherford knocking 



