34 Presidential Address 



and chemical affinity; it is therefore the 

 storehouse of potential energy. 



Matter moves, but Ether is strained. 



What we call elasticity of matter is 

 only the result of an alteration of con- 

 figuration due to movement and read- 

 justment of particles, but all the strain 

 and stress are in the ether. The ether 

 itself does not move, that is to say it does 

 not move in the sense of locomotion, 

 though it is probably in a violent state 

 of rotational or turbulent motion in its 

 smallest parts; and to that motion its 

 exceeding rigidity is due. 



As to its density, it must be far greater 

 than that of any form of matter, millions 

 of times denser than lead or platinum. 

 Yet matter moves through it with per- 

 fect freedom, without any friction or 

 viscosity. There is nothing paradoxical 

 in this: viscosity is not a function of 

 density; the two are not necessarily 

 connected. When a solid moves through 

 an alien fluid it is true that it acquires 

 a spurious or apparent extra inertia 

 from the fluid it displaces; but, in the 



