1902.] on the Electronic Theory of Electricity. 177 



tive or negative according to the direction of the strain, and to every 

 positive electron there is a corresponding negative one. Atoms 

 according to liim are collocations of electrons in stable orbital motion 

 like star clusters or systems. 



An electron in motion is in fact a shifting centre of aether strain 

 and it can be displaced through a stationary aether just as a kink or 

 knot in a rope can be changed from place to place on the rope. 



An electron in vibration creates an aether wave, but it radiates only 

 when its velocity is being accelerated and not when it is uniform. 



The type of aether which Larmor assumes as the basis of his 

 reasoning is one which has a rotational elasticity, that is to say, the 

 various portions of it do not resist being sheared or slid over each 

 other, but they resist being given a rotation round any axis. Starting 

 from these postulates and guided by the general and fundamental 

 principle of Least Action, he has erected a consistent scheme of 

 molecular physics in which he finds an explanation of most observed 

 facts. 



The discovery by Zeeman of the effects of a strong magnetic field 

 in triplicating or multiplicating the lines in the spectrum of a flame 

 placed in a magnetic field meets with an obvious explanation when we 

 remember that the effect of a magnetic field on an electron in motion 

 is to accelerate it always transversely to its own motion and the 

 direction of the field. Hence it follows that a magnetic field properly 

 situated will increase the velocity of an electron rotating in one 

 direction and retard it if rotating in another. But a linear vibration 

 may be resolved into the sum of two oppositely directed circular 

 motions and accordingly a magnetic force properly applied must act 

 on a single spectral line, which results from the vibration of an 

 electron in such manner as to create two other lines on either side, 

 one representing a slightly quicker and the other a slightly slower 

 vibration. 



The notion of an electron or point charge of electricity as the 

 ultimate element in the structure of matter having been accepted, we 

 are started on a further inquiry as to the nature of the electron itself. 

 It is obvious that if the electron is a strain centre or singular point 

 in the aether, then corresponding to every negative electron there 

 must be a positive one. In other words, electrons must exist in pairs 

 of such kind that their simultaneous presence at one point would 

 result in the annihilation of both of them. 



On the view that material atoms are built up of electrons we have 

 to seek for a structural form of atom which shall be stable and equal 

 to the production of effects we find to exist. 



The first idea which occurs is that an atom may be a collection of 

 electrons in static equilibrium. But it can be shown that if the elec- 

 trons simply attract and repel each other at all distances according to 

 the law of the inverse square no such structure can exist. The next 

 idea is that the equilibrium may be dynamic rather than static, that 

 an atom may consist of electrons, as suggested by Larmor, in orbital 



Vol. XViI. (No. 96.) n 



