6 9 6 



NA TURE 



\'| IVEMBER 25, 1922 



Letters to the Editor. 



[The Editor does not hold himself responsible for 

 opinions expressed by ids correspondents. Neither 

 can he undertake to return, or to correspond with 

 the writers of, rejected manuscripts intended for 

 this or any other part of Nature. No fiotice is 

 taken of anonymous communications.] 



Speculation concerning the Positive Electron. 



I write hypotheticallv, and in an interrogative 

 mood except that I scarcely expect a present answer, 

 but it is simpler to state a hypothesis with pre- 

 posterous dogmatism, in imitation of the unconscious 

 manner of the crank. 



A.i 1 aiding to Larmor's theory the positive and the 

 negative electrons can only differ, or at least must 

 ( liK-llv differ, in one being the mirror-image of the 

 other. One for example might be a concentrated 

 locked right-handed screw-twist in the Ether, while 

 the other would be a left-handed contortion of 

 precisely the same kind, simultaneously and inevitably 

 produced, and connected with its fellow by transfer- 

 able lines of force. Both would incidentally have to 

 involve also a residual strain or tension, proportional 

 to the square of the twist and inversely as the 

 distance from it. 



Needless to say, no positive electron in this sense 

 has yet been discovered. If they exist, why not ? 

 Because electrons of both kinds are so extremely 

 mobile, and the forces between them so immense, 

 that they instantly bind themselves together into 

 a compact and exceedingly stable structure, consisting 

 of some hundreds or thousands of each kind ; the 

 simplest and lightest of which composite structures 

 we know as the proton or hydrogen nucleus. Short 

 of that grouping, the compound units are either too 

 fully neutralised to be perceived, or else too greedy 

 of each other to exist separately. The proton, for 

 the first time, allows a single electron to be free 

 enough to revolve permanently round the close- 

 packed group without being utterly absorbed and 

 incorporated in its composition. 



A number of protons can unite and form the 

 nuclei of other atoms, and in this case several free 

 electrons can remain incompletely assimilated, so as 

 to form a satellite system characteristic of each 

 different element. Such composite nuclei can be 

 shattered by adequate means, but the single nuclei 

 are very stable, and the proton itself has not yet 

 been near disintegration ; nor is it clear whether 

 anything detectable could result from its fracture, 

 especially if the fragments were electrically neutral. 



But now comes a question, difficult to answer on 

 the mirror-image hypothesis : — Why should only- 

 negative electrons occur in the satellite systems ? 

 Why should not some atoms have nuclei with a 

 surplus of negative charge, and be attended by 

 positive electrons - 



Possibly an answer may be forthcoming from those 

 who either now or hereafter understand the formation 

 of an a-partiele, and why it has two positive 

 and always positive — charges ; for it seems to form 

 an essential intermediate ingredient in the building-up 

 process. 



But assuming that no answer is forthcoming ; are 

 we quite sure that no atoms are of the exceptional 

 variety ' Can such a variety exist? It seems a 

 possibility just worthy of contemplation, unless 

 experimental observation already absolutely negatives 

 Photo-electric evidence is strong; the Zeeman 

 effect appears conclusive. But is it final ? It 

 demonstrates clearly enough that the radiating 

 particle has an electro-chemical equivalent of the 



NO. 2769, VOL. I IO] 



order 10', and is therefore an electron of some kind, 

 but is it conclusive about the sign in all cases ? 

 Perhaps it is : but there is no harm in reconsidering . 

 a conclusion occasionally, even if the already accepted 

 answer turns out quite indubitable. 



If all radiation is from the negative electron only, 

 that curious fact would seem to point to some striking 

 qualitative difference between the negative and the 

 hypothetical positive electron : a difference which 

 on Larmor's theory of the Ether is difficult to grant, 

 though it may have to be granted. It is owing to 

 tins difficulty that there has arisen the otherwise 

 attractive idea of a positive electron so intensely 

 concentrated as to be about 1 /1800th of the linear 

 dimension of the negative electron, and therefore 

 to possess incomparably greater inertia. This may 

 be the right way out of the difficulty, but it requires 

 proof. 



If, pending proof, we try to work with a mirror- 

 image pair of electrons, can we anyhow account for 

 the apparent fact that atoms have only negative 

 satellites? Perhaps thus: — Consider a crowd of 

 new-born electrons, both positive and negative. If, 

 among the manifold chances of structural packing, 

 something less than half of the atomic nuclei formed 

 were of the kind with positive satellites, while the 

 other approximate half were of the negative satellite 

 variety, the two classes would speedily combine 

 with a violence inappropriate to anything that can 

 be called molecular combination. They would 

 thereby form the tight-packed and stable nuclei 

 of heavier atoms, until the complexity was great 

 enough to result in instability. That ma'; be how 

 the heavier atoms were formed. If the packing 

 took place by chance, there might be a small surplus 

 of one variety in excess. 



The combination of nuclei would only cease when 

 they were protected by a screen of similar electrons ; 

 their sign might be + or might be - but could not 

 be both. In other words the resulting atoms could 

 not be of opposite varieties ; the satellites of the 

 surplus variety must be all of one sign, or the atoms 

 would combine with each other and form a new 

 substance. Thus we could get the outlying satellites 

 of one sign, either in every case or in so vast a 

 preponderance of cases that no exceptions are as yet 

 manifest. In the nascent stages there might be a 

 random distribution of the two varieties, in numbers 

 nearly equal but not accurately equal, like the male 

 and female of a population ; then most of them 

 would mate and constitute higher nuclei, while the 

 variety which happened to be in the majority would 

 remain as it was, and become conspicuous. The 

 number mated might be a hundred times greater 

 than the number of outstanding single ones and 

 yet these last would be what we know as the atoms 

 of the elements familiar to-day. It is plain that the 

 number of protons embedded in the nuclei of all the 

 atoms must be in excess of the number of atoms 

 themselves. The atoms themselves represent the 

 surplus, the excess kind that could find no partners. 

 The number of protons embedded in atomic nuclei are 

 (1 + 2 +3 4- . . . + 92) 



92 



times the number of known 



atoms, say 46 times as numerous. 



Some fallacy here : for the elements are not all 

 equally plentiful. But the middle ones are on the 

 whole the most plentiful, and the statement may pass 

 as a rough approximation. 



Directly a positive variety of atom gets loose, it 

 will combine with the nearest negative variety 

 accessible, and push it a step or two up the series. 

 In that way heavier elements may still occasion. 1 1 ly 

 be born. The free life-time of the less plentiful 

 variety would be too brief for ordinary detection ; 



