6 MeldruM, Development of the Atomic Theory. 



Thomas Thomson was Dalton's champion during 

 the controversy, and he stoutly resisted Higgins' claims. 

 The position he adopted is a specially interesting one. 

 He declared that although Higgins' book had been widely 

 read, no one had perceived the atomic theory in it. He 

 therefore denied that the theory was there. This is not 

 an answer, however, but an argument, and one that 

 Thomson could hardly have used if he had kept in mind 

 the reception Dalton's theory met with when it was 

 launched upon the world. (See the sixth paper of this 

 series.) 



Humphry Davy, for instance, ignored it for long, 

 and disparaged it when it was forced upon his notice. One 

 can hardly wonder, then, that Higgins' speculations should 

 have been disregarded, for they appeared many years 

 before, under cover of a contribution to the phlogiston 

 controversy. 



Thomson, however, offered the testimony that he 

 himself had failed to perceive the theory in Higgins' book. 

 " I have certainly affirmed that what I consider as the 

 atomic theory was not established in Mr. Higgins' book . . . 

 I have had that book in my possession since the year 1798, 

 and had perused it carefully ; yet I did not find anything 

 in it which suggested to me the atomic theory. That a 

 small hint would have been sufficient I think pretty 

 clear from this, that I was forcibly struck with Mr. Dalton's 

 statement in 1804, though it did not fill half an octavo 

 page."^ 



This is hardly enough to establish Thomson's case. 

 It amounts to the plea that he was not making a mistake 

 in the year 18 14, simply because he could not have made 

 it in the year 1798. Charles Darwin was a humbler 



" Annals of Phil., 3, 331, 1S14. 



