Atoms. 197 



r 



The "atom" of the modern mathematical 

 physics has, accordingly, given up its preten- 

 sion to stand as an absolute beginning, and 

 now serves only as a necessary rest for ex- 

 hausted analysis, before setting forth on the 

 return journey of deduction. " A simple ele- 

 mentary atom," says Professor Balfour Stewart, 

 " is probably in a state of ceaseless activity and 

 change of form, but it is, nevertheless, always 

 the same." 1 "The molecule," (here identical 

 with "atom," as the author is speaking of a 

 simple substance, as hydrogen), " though indes- 

 tructible, is not a hard rigid body," says Pro- 

 fessor Clerk Maxwell, "but is capable of 

 internal movements, and when these are ex- 

 cited it emits rays, the wave-length of which 

 is a measure of the time of vibration of the 

 molecule." 3 But "change of form" and "in- 

 ternal movements " are impossible without 

 shifting parts, and altered relations ; and where 

 then is the final simplicity of the atom ? It 

 is no longer a pure unit, but a numerical whole. 

 And as part can separate from part, not only 

 in thought but in the phenomena, how is it an 

 " atom " at all ? " What is there, beyond an 

 arbitrary dictum, to prevent a part which 



1 " The Conservation of Energy," p. 7. 

 * "A Discourse on Molecules," p. 12. 



