46 THE ADVANCE OF SCIENCE 



value of pothesis, however, did not lie in the two 

 pothesis; points which Democritus and his followers 

 would have considered essential — namely, 

 the indivisibility of the 'atoms' and the 

 presence of an interatomic vacuum — but 

 in the assumption that, to the extent to 

 which our means of analysis take us, ma- 

 it predi- terial bodies consist of definite minute 



eates the , „ , . , « -i • i 



cx i s t. masses, each of which, so lar as physical 

 SsaE an( l chemical processes of division go, 

 matter. ma y ^ e re g ar< i e ^ as a unit — having a 



practically permanent individuality. Just 

 as a man is the unit of sociology, without 

 reference to the actual fact of his divisi- 

 bility, so such a minute mass is the unit 

 of physico-chemical science — that small- 

 est material particle which under any 

 given circumstances acts as a whole.* 

 The doctrine of specific heat originated 



* 'Molecule' would be the more appropriate name 

 for such a particle. Unfortunately, chemists employ 

 this term in a special sense, as a name for an aggrega- 

 tion of their smallest particles, for which they retain 

 the declination of 'atoms.' 



