ATOMIC THEORY AND RADIOACTIVITY 199 



Now speculative instinct is extremely valuable as a guide 

 among new facts, but it is not powerful enough to be able to 

 withstand them. Prof. Armstrong feels the difficulty, and 

 presently invents a supplementary explanation, devising for 

 the purpose not only the as yet unknown substance "pro- 

 tohelium," but also another hypothetical element which he 

 names "something else"; and by then postulating strong 

 chemical affinity between his two imaginary materials, he 

 manages to get along. Here are his words, beginning with a 

 pertinent question : 



" Why, as radium decomposes so slowly, does it decompose 

 at all ; why does it not all blow up suddenly, like an ordinary 

 explosive ? There is but one explanation — that, like the other 

 mere chemical compounds Prof. Soddy speaks of so slightingly, 

 it is always being decomposed reversibly — into protohelium 

 and something else, the which products reunite more frequently 

 than they part company and escape, the protohelium after it has 

 united with itself; the radium does not blow up, because of 

 the intense affinity of protohelium for its companion product 

 of change." 



This is surely an extraordinary statement for a scientific 

 man ; and we are constrained to ask, why does Prof. Armstrong 

 strain himself into this singular attitude of gratuitous hypothesis, 

 instead of yielding gracefully to the logic of facts ? He gives 

 the answer himself; though he is applying the criticism to other 

 workers who have, as he says, " so long overlooked the 

 potentialities of protohelium " ; it is, he says, 



" human nature to have chief affection for one's own children ; 

 to be blind to their faults and disinclined to seek virtues in those 

 of others." 



And in a paragraph already quoted he specifies the "child" 

 he himself is fond of: 



11 When argon was first described in 1895 by Rayleigh and 

 Ramsay, I ventured to assert such a view in explanation of its 

 apparently complete inactivity." 



And so he goes on to suggest that 



" it were time to discard the fiction that the gases of the 

 argon family are monatomic molecules which has so long 

 retarded progress." 



Here we come to the root of the matter ; and we here discern 

 the fundamental cause of his quixotic tilting at ascertained 



