THE PROGRESS OF PHYSICS. 169 



" That is to say," he continues, " matter is not 

 continuous and homogeneous, but is discontinuous; 

 being composed of material particles, whatever they 

 are, and non-material spaces. There is every reason 

 to be certain that these spaces are full of a connecting 

 medium, full of ether; there is no really void 

 space." 



But while the atomic view is generally accepted, 

 there is less unanimity as to the fittest conception of 

 the atom. " No one now believes that an atom is 

 simply a vortex ring of ether, and that the rest of 

 the ether is stagnant fluid in which the vortex rings 

 sail about. Any quantity of difficulties surround 

 such an hypothesis as that. Its apparently attrac- 

 tive simplicity is superficial. ^Nevertheless it is not 

 to be supposed that every hydro-dynamical theory 

 of the universe is thereby denied. It is quite con- 

 ceivable that a single kind of fluid in different kinds 

 of motion some kinds of motion not yet imagined 

 perhaps may possibly be found capable of explain- 

 ing all the facts of physics and chemistry." * 



"I hold," says Prof. Lodge, "that the ether is 

 most certainly not atomic, not discontinuous ; it is an 

 absolutely continuous medium, without breaks or 

 gaps or spaces of any kind in it, the universal con- 

 nector, permeating not only the rest of space, but 

 permeating also the space occupied by the atoms 

 themselves. The atom is something superposed upon, 

 not substituted for, the ether, it is most likely a defi- 

 nite modification of the ether, an individualisation, 

 with a permanent existence and faculty of locomotion, 

 which the ether alone does not possess. Matter is that 

 which is susceptible of motion. Ether is that which 



* Modern Views of Matter, International Monthly, I. 

 (1900), pp. 499 and 501. 



