1908] on the Ether of Space. 65 



of a vacuum to the maguetic force, and the o^eneral character of 

 magnetic phenomena external to the magnet, I am much more 

 inclined to the notion that in the transmission of the force there is 

 such an action, external to the magnet, than that the effects are merely 

 attraction and repulsion at a distance. Such an action may be a 

 function of the aether ; for it is not unlikely that, if there be an aether, 

 it should have other uses than simply the conveyance of radiation." 



This conjecture has been amply strengthened by subsequent in- 

 vestigations. 



One more function is now being discovered ; the ether is being 

 found to constitute matter — an immensely interesting topic, on which 

 there are many active workers at the present time. I will make a 

 brief quotation from your present Professor of Natural Philosophy 

 (J. J. Thomson), where he summarises the conclusion which we all 

 see looming before us, though it has not yet been completely 

 attained, and would not by all be similarly expressed : — 



" The ivhole mass of any body is just the mass of ether surrounding 

 the body which is carried along by the Faraday tubes associated with 

 the atoms of the body. In fact, all mass is mass of the ether ; all 

 momentum, momentum of the ether ; and all kinetic energy, kinetic 

 energy of the ether. This view, it should be said, requires the 

 density of the ether to be immensely greater than that of any known 

 substance." 



Yes, far denser — so dense that matter by comparison is like 

 gossamer, or a filmy imperceptible mist, or a milky way. Not unreal 

 or unimportant — a cobweb is not unreal, nor to certain creatures is 

 it unimportant, but it cannot be said to be massive or dense ; and 

 matter, even platinum, is not dense when compared with the ether. 

 Not till last year, however, did I realise what the density of the 

 ether must really be,* compared with that modification of it which 

 appeals to our senses as matter, and which for that reason engrosses 

 our attention. If I have time I will return to that before I have 

 finished. 



Is there any other function possessed by the ether, which, though 

 not yet discovered, may lie within the bounds of possibility for future 

 discovery ? I believe there is, but it is too speculative to refer to, 

 beyond saying that it has been urged as probable by the authors of 

 " The Unseen Universe," and has been thus tentatively referred to by 

 Clerk Maxwell :— 



" Whether this vast homogeneous expanse of isotropic matter is 

 fitted not only to be a medium of physical interaction between dis- 

 tant bodies, and to fulfil other physical functions of which, perhaps, 

 we have as yet no conception, but also ... to constitute the material 

 organism of beings exercising functions of life and mind as high or 



* See Lodge, Phil. Mag., April 1907 



Vol. XIX. (No. 102) 



