24 Larmor, Physical Aspect of the Atomic Theory. 



the last dozen years (J. J. Thomson, Schuster, etc.) have, 

 however, shown that in rarefied gases, where the molecules 

 are far too widely separated for any appreciable amount of 

 immediate interchange, disruptive electric discharge 

 establishes itself by driving the electron into the open, 

 where its intense and extended field of energy has made 

 it far more amenable to physical scrutiny than the more 

 self-contained neutral material molecules could ever 

 themselves have been. The enormous speed with which 

 it travels, approximating often towards that of radiation, 

 which is the maximum conceivable in an aether not 

 subject to rupture, can perhaps be ascribed only to a 

 comparable orbital velocity when the electron is in the 

 molecule, from which it occasionally glides away through 

 some kind of overbalancing of the internal kinetic adjust- 

 ments, either enforced by disruptive electric excitation or 

 spontaneous as in the case of radio-active substances. It 

 appears significant that in the atomic disintegration 

 involved in the later case the emission is at much greater 

 speed, almost up to the limit of what is possible. 



Considerations of this kind concur with the very precise 

 magnetic subdivision of the lines of the spectrum dis- 

 covered by Zeeman and Lorentz. Since Maxwell's co- 

 ordinating analysis, we are certain that light and radiation 

 generally are phenomena of electric disturbance : or more 

 precisely, as he put it, we know that electrostatic 

 phenomena are manifestations of strain, and electro- 

 magnetic phenomena are manifestations of interaction 

 of strain and inertia, in the same medium whose 

 undulations constitute radiation. As soon as a definite 

 structural picture could be formed for an atom of 

 electricity as a region of strain abutting on a central 

 nucleus at which it is locked together, even though the 

 free mobility of the nucleus has to be assumed rather 



