HI8T0EY OF THE ATOMIC THEORY. 285 



The mind never ceases to be strange to us, and if our pic- 

 tures of men are incorrect, it often arises from our desire to 

 comprehend thoroughly the whole. This is always diflBcult, 

 probably impossible, still more so in the case of one so little 

 demonstrative. But it is not here desired to describe that sub- 

 stratum of mind common to all men, but those striking features 

 which stood above the average man, and are the true source 

 of our interest. 



The first thing that we observe in Dalton is clearness of 

 conception; he knows what he thinks, and can define it. 

 This is very clear through all his course, every thought is 

 squared and finished. To this more than anything else I 

 attribute his first idea of atoms. He was obliged to conceive 

 of gas, and how could he do it without giving shapes to the 

 parts ? Gases could not be without parts, they expanded and 

 contracted, and so the parts became essential to them. 



The next thing to observe is directness. He went to his point 

 rapidly. His experiments are simple, and, although rude, are 

 exceedingly appropriate. It must, however, be remembered 

 that although simplicity is at times beautiful, it cannot be 

 attained in experiment so easily now as then. He pre- 

 pared the way for more complex methods. Great clearness 

 of conception often leads the mind to put down its results in 

 form and figure, giving a mathematical character to them. It 

 loses the poetical distance by working at the foreground, but 

 does not forget that the foreground has a beauty and truth of 

 its own. 



The third characteristic is tenacity. His conceptions once 

 formed seemed never to fade, or were with difficulty eradicated. 

 This is natural to a mind with strong conceptions. Its own 

 thoughts become its material, much more than anything said 

 or done by others, and it prefers to reason from its own data, 

 being those best known to it. This was remarkably seen in 

 Dalton. 



