of Electrons in an Elastic Solid yEther. 135 



something beneath, something much nearer to the direct sug- 

 gestions of our muscular sense. If we cannot hope and need 

 not seek, as Sir J. Larmor seems sometimes to imply, to probe 

 to a lower depth than the action principle (8 j* Lett = 0) , by 

 all means let us readmit the discredited action at a distance, 

 as fine an example of the principle as we could desire. 



Sir Oliver Lodge seems to strike the correct note when 

 he, somewhere, calls upon us to explain everything in the 

 physical world by pushing and pulling, or indeed by pushing 

 and not pulling. Here we seem to tind cause for the fasci- 

 nation exercised by the vortex theory of matter. Carry the 

 pushing view to its logical conclusion. The now familiar 

 perfect liquid is alone left from which to extract our bricks 

 and straw wherewith to build the world as it appears. If 

 this liquid is our ultimate goal then most assuredly the 

 simplest thing we know, free aether, is simple only in 

 appearance for its properties are not those of a liquid at rest. 



Even granting (without conceding any imperative necessity 

 to do so) that this simplest thing ultimately may come to be 

 explained by the simplest constitution, that of a perfect liquid; 

 it appears to me that the most hopeful intermediate step to 

 take is to assign to the aether a constitution next in simplicity 

 to that of a perfect liquid, namely, that of an isotropic solid. 



Probably most people think that the elastic solid constitu- 

 tion of the aether has been applied to modern views and found 

 wanting. Now, however dubious some of" our contentions 

 may be, one result comes out with certainty from the dis- 

 cussion below, and that is that the elastic solid theory has 

 not as yet been so much as tried. There is a good reason 

 for this, namely, that for nearly forty years, if not longer, 

 there has appeared to be an insuperable difficulty in recon- 

 ciling any elastic solid theory with the facts of optical re- 

 flexion and refraction at the boundary of a transparent body. 

 That difficulty has been surmounted (so we claim) in a paper 

 on an elastic solid aether appearing in the Phil. Mag. for 

 April 1909, p. 553. It has been surmounted on the old 

 statical lines, where the difficulty alone really existed, by a 

 reconsideration of the transition layer at the boundary. 

 Moreover, those statical lines are not the lines along which 

 the train of modern speculation mainly runs. 



We here accept the general picture presented to us by 

 recently acquired knowledge of atoms and electrons, and the 

 attendant hypothesis that the atom is what we know it to be 

 largely because formed of orbitally moving electrons, and we 

 accept the view that free aether is stagnant. 



If free aether is a stagnant isotropic elastic solid what can 



