340 Scientific Proceedings, Royal Dublin Society. 



the molecules are moving individually independently, and in the same 

 manner as they do in a gas at rest. For instance, if a region in 

 which there were many vortex atoms were in communication with 

 one in which there were only a few, the vortex atoms would diffuse 

 in a current out of the former into the latter. Now the momentum 

 of this current for a given number of vortex atoms transferred per 

 second across unit area would depend on the momentum of each 

 vortex atom, and as this momentum is not proportional to the 

 velocity of the atom, and is a function of its temperature, it is 

 evident that the momentum of such a current would be a function 

 of its temperature. 



The whole notion that atoms are vortex rings in a medium 

 raises serious difficulties as to the amount by which this medium is 

 carried along by the motion of the earth, for instance, and by solid 

 bodies enclosing masses of gas. If the earth does not ca,rry the 

 medium with it, the vortex atoms in the air must be so energetic 

 as to be moving at nineteen miles a second through it, and their 

 size and momentum must vary considerably from day to night, as 

 they are going so much more rapidly at night than by day. 

 Similarly the momentum of an enclosed mass of gas would vary 

 with its temperature, if moving the enclosure only moves the en- 

 closed vortices. On the other hand, if the earth does carry the 

 medium with it, what withstands the centrifugal force of this 

 revolving medium? Why does it not originate an enormous 

 vortex? This and similar difficulties seem to point to the con- 

 clusion that to suppose atoms to be simple ring vortices in a 

 perfect liquid can hardly be an adequate theory. There seems 

 very good reason for believing that the hypothesis that the 

 medium is simply a perfect liquid is hardly sufficient. It cer- 

 tainly is not sufficient to explain luminous and electrical and 

 magnetic phenomena, to suppose the ether to be simply a perfect 

 liquid at rest ; and though it is too much to say that it will not 

 ultimately be found a sufficient foundation for a theory of matter 

 and material phenomena, at present, at least, there seems very 

 little prospect of anybody's inventing how it ought to be moving, 

 in order to have the known properties of the ether ; and even 

 the ingenious attempt to explain matter as due to simple ring 

 vortices in it seems too simple to be adequate. 



