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Proceedings of the Royal Society of Edinburgh. [Sess. 
the “ why ” of it, until, when the final transference is complete, there 
ceases to be any difference between Why and How. 
Until fuller certainty comes, it is well that every hypothetically 
possible line of advance should be explored. It is in this sense, and 
not in the sense of singleness of possibility, that the importance of 
Professor Whittaker’s suggestion regarding quantum action, together 
with the suggestion of Sir Alfred Ewing regarding atomic magnetism, 
upon which it is based, really lies. Thus about ten years ago I suggested 
a combined electrostatic and electromagnetic atomic structure which 
might give quantum action of the type considered by Professor Whittaker 
and quantum magnetic moment of the type considered by Sir Alfred 
Ewing as well as radiational quantum action. And about the same 
time Professor Conway described a different mechanism for radiational 
quantum emission. I have also shown that known magneto-crystalline 
and ferromagnetic properties can be deduced from a space-lattice 
distribution of molecular magnets without the small pole clearance 
necessitated by Sir Alfred Ewing’s scheme. Indeed, the chief importance 
of his scheme lies in the fact that it constitutes a cubic arrangement of 
molecular magnets, effectively possessed of variable magnetic moment, 
and which have their linear dimensions small relatively to their central 
distances. It is only in the light of many suggestions that the ultimate 
solution may be found. In no case can a simply constituted atom of the 
electronic type be sufficient, although it is so wonderfully sufficient when 
the complexity is eluded by the quantum postulates. 
It seems to me that Professor Whittaker’s model only furnishes 
perfectly elastic electron-atom collisions by postulating the prevention 
of radiation, just as the quantum-dictum of no radiation in steady 
electronic orbital motion does. In other words, it leaves part of the 
essential mechanism undescribed. And it seems also that there may be 
difficulty in connection with the acceleration of an atom containing 
discrete electric charges, and also discrete distributions of moving 
magnetism, in consequence of the mutual influence of these charges 
and magnetic distributions through the medium of the ether; so that 
Galilei-wise motion may conceivably be impossible. 
But such difficulties, should they exist, in no way detract from the 
value of a suggestion which for the first time exhibits a mechanism 
capable of giving unreversed action upon an electron in its motion 
towards, through, and away from an atom. 
(Issued separately July 4 , 1922 .) 
