EVOLUTION THE MASTER-KEY 



chemistry. To have treated of these sciences systemat- 

 ically would have compelled him, it is probable, to sup- 

 plement his theory of evolution by other laws." 



Now we have already seen that Spencer did 

 indicate the application of the theory of evolution 

 to the inorganic sciences. That he did not do so 

 at length was due to the fact that his object in 

 writing the synthetic philosophy was to reach the 

 principles upon which morality is grounded. With 

 a task estimated at twenty years really to occupy 

 nearly double that time before him, he could 

 not spare the time to deal with the relatively 

 unimportant aspects of evolution. 



But, curiously enough, Mr. Harrison's objection 

 was more than met the following evening in a re- 

 markable lecture on the "Structure of the Atom," 

 delivered by Professor J. J. Thomson, of Cambridge, 

 before the most distinguished audience I have ever 

 seen at the Royal Institution. In that brilliant 

 and memorable lecture Professor Thomson, who 

 is the chief author of the new theory of matter, and 

 whose views were so amusingly misunderstood in 

 Mr. Balfour's Presidential Address to the British 

 Association at its Cambridge meeting in 1904, gave 

 us a most satisfying account of atomic evolution, 

 so final and complete that I must outline it in con- 

 cluding the present chapter. 



The actual unit of matter, as we have already 



seen, is not the so-called atom but the electron, 



which is really a literal atom of negative electricity. 



Now "like electricities" tend to repel one another, 



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