66 Presidential Address 



properties, make the ether the most inter- 

 esting as it is by far the largest and most 

 fundamental ingredient in the material 

 cosmos. 



As Sir J. J. Thomson said at Winnipeg: 



The ether is not a fantastic creation of the 

 speculative philosopher ; it is as essential to us 

 as the air we breathe. . . . The study of this 

 all-pervading substance is perhaps the most 

 fascinating and important duty of the physicist. 



Matter it is not, but material it is; it 

 belongs to the material universe and is 

 to be investigated by ordinary methods. 

 But to say this is by no means to deny 

 that it may have mental and spiritual 

 functions to subserve in some other order 

 of existence, as Matter has in this. 



The ether of space is at least the great 

 engine of continuity. It may be much 

 more, for without it there could hardly 

 be a material universe at all. Certainly, 

 however, it is essential to continuity; 

 it is the one all-permeating substance 

 that binds the whole of the particles 

 of matter together. It is the uniting 



