28 SCIENCE PROGRESS 



into here it is perhaps desirable that the name " magneton " 

 should not be applied in this connection, and that " A Ring 

 Electron Theory, etc.," would describe the author's views in 

 more accurate terms. For that is his essential postulate, viz. 

 that the electron itself is magnetic, having, in addition to the 

 usual properties attributed to negative electricity, the pro- 

 perties of a current circuit whose radius is of the same order of 

 magnitude as, but somewhat smaller than, that of a hydrogen 

 atom. " It may be pictured by supposing that the funda- 

 mental negative charge is distributed continuously around a 

 ring which rotates on its axis with a peripheral velocity of the 

 order of that of light, and presumably the ring is extremely 

 thin." 



Parson himself adopts in his paper the Thomson positive 

 sphere for the massive part of the atom, but it appears that 

 the conception may be associated with the Rutherford nucleus 

 as readily. It is in its explanation of the chemical and mag- 

 netic behaviour of matter that this model has its most signal 

 success. As mentioned above, orbital motion of electricity 

 within the atom seems essential for any explanation of the 

 magnetic properties of matter, yet such orbital motion implies 

 radiation of energy, and ultimate collapse of the atom if the 

 electricity is regarded as in the form of minute spherical or 

 spheroidal charges rotating in orbits large in comparison with 

 the size of these charges. It has long been known that if the 

 number of electrons in motion in one orbit were great enough, 

 the radiation would be much reduced, even six making the 

 loss of energy extremely slow. But there are serious objec- 

 tions to the employment of this result to help us out of the 

 radiation difficulty. The lighter atoms, such as those of 

 Hydrogen, Helium, Lithium, do not contain enough electrons 

 to form even one such orbit — at least enough of the outer and 

 more loosely bound electrons which play a part in chemical, 

 magnetic and optical phenomena. Again, for diamagnetic 

 atoms it is necessary to assume the existence of independent 

 orbits in the atom that are so great in number or else undergo 

 such rapid variations that they can be considered as having 

 their axes distributed uniformly in three dimensions in order 

 to account for a zero resultant magnetic moment. Separate 

 rings of this sort cannot maintain their individualities unless 

 they differ very markedly in radius, and this condition would 



