A HISTORY OF SCIENCE 



tions which amounted to qualitative differences. He 

 might claim for his largest atom the same quality of 

 substance as for his smallest, but so long as he con- 

 ceived that the large atoms, when adjusted together to 

 form a tangible substance, formed a substance differ- 

 ent in quality from the substance which the small 

 atoms would make up when similarly grouped, this 

 concession amounts to the predication of difference of 

 quality between the atoms themselves. The entire 

 question reduces itself virtually to a quibble over the 

 word quality. So long as one atom conceived to be 

 primordial and indivisible is conceded to be of such 

 a nature as necessarily to produce a different impres- 

 sion on our senses, when grouped with its fellows, 

 from the impression produced by other atoms when 

 similarly grouped, such primordial atoms do differ 

 among themselves in precisely the same way for all 

 practical purposes as do the primordial elements of 

 Anaxagoras. 



The monistic conception towards which twentieth- 

 century chemistry seems to be carrying us may per- 

 haps show that all the so-called atoms are compounded 

 of a single element. All the true atoms making up that 

 element may then properly be said to have the same 

 quality, but none the less will it remain true that the 

 combinations of that element that go to make up the 

 different Daltonian atoms differ from one another in 

 quality in precisely the same sense in which such tangi- 

 ble substances as gold, and oxygen, and mercury, and 

 diamonds differ from one another. In the last analysis 

 of the monistic philosophy, there is but one substance 

 and one quality in the universe. In the widest view 



166 



