74 Dr. 0. V. Burton 



on a 



In any case it is instructive to trace out some of the 

 consequences which might be expected to follow from the 

 propagation of compressional waves through a very slightly 

 compressible aether ; the more so as we are led to certain 

 conclusions which, although essentially based on the ordinary 

 postulates of dynamics, are at variance with some traditional 

 or instinctive views. 



5. The second innovation referred to concerns the nature 

 and mode of progression of the centres of enhanced com- 

 pressibility, which are assumed to be associated with atomic 

 matter. If the nucleus of an electron is taken to be a 

 vacuous cavity, the question of free mobility of this nucleus 

 through the aether presents some difficulty, even when we 

 suppose that the electron itself is essentially constituted by a 

 self-equilibrating distribution of strain in the aether sur- 

 rounding the nucleus. But now, discarding for the moment 

 a too minute scrutiny of aetherial constitution, so that we 

 may regard the aether as a continuous medium, let us 

 suppose that the nucleus of an electron *, instead of being- 

 vacuous, is merely a region of somewhat diminished density. 

 (Though increased compressibility may not be inevitably 

 associated with diminished density, it is convenient to assume 

 such a relation for preliminary descriptive purposes. In the 

 sequel this question is treated more generally.) This implies 

 that, in the complete strain-distribution which constitutes the 

 electron, there is included some degree of expansion in the 

 nuclear region. An electron thus constituted may more 

 readily be conceived as freely mobile through the aether, no 

 vacuous cavity being present to complicate the problem ; 

 so that any infinitesimal displacement of the electron is 

 simply equivalent to the impressing of a differential strain 

 upon the medium. 



6. This assumption as to the nature of an electronic 

 nucleus is admittedly gratuitous, but apart from the difficulty 

 regarding mobility which it was designed to remove, it has 

 the advantage of greatly simplifying the dynamics of the 

 problem proposed. So far as we are concerned with the 

 distribution of resultant aetherial motion from point to point, 

 we may treat each moving electron as a doublet comprising 

 a source and a neighbouring sink, while it is shown that the 

 resultant of the hydrodynamical (gravitational) forces f 



* The necessity for distinguishing-, in this connexion, between positive 

 and negative electrons is considered in Appendices A and B. 



T That is to say of those forces which are concerned in palpable 

 aetherial motions ; our scrutiny being minute enough to take account of 

 variations of aetherial qualities through the region occupied by an 

 electron, but not so minute that the aether ceases to appear to us as a 

 continuous medium. 



