THE ETHER OF SPACE 291 



and mind may be something quite other than physical 

 proximity, and in denying action at a distance across empty 

 space I am not denying telepathy or other activities of a 

 non-physical kind; for although brain disturbance is cer- 

 tainly physical, and is an essential concomitant of mental 

 action, whether of the sending or receiving variety, yet we 

 know from the case of heat that a material movement can 

 be excited in one place at the expense of corresponding 

 movement in another, without any similar kind of trans- 

 mission or material connection between the two places: the 

 thing that travels across vacuum is not heat. 



In all cases where physical motion is involved, however, 

 I would have a medium sought for; it may not be matter, 

 but it must be something; there must be a connecting link 

 of some kind, or the transference cannot occur. There can 

 be no attraction across really empty space. And even 

 when a material link exists, so that the connection appears 

 obvious, the explanation is not complete; for when the 

 mechanism of attraction is understood, it will be found 

 that a body really only moves because it is pushed by 

 something from behind. The essential force in nature is 

 the vis a tergo. So when we have found the " traces" or 

 discovered the connecting thread, we still run up against 

 the word "cohesion," and ought to be exercised in our 

 minds as to its ultimate meaning. Why the particles of a 

 rod should follow, when one end is pulled, is a matter re- 

 quiring explanation ; and the only explanation that can be 

 given involves, in some form or other, a continuous medium 

 connecting the discrete and separated particles or atoms of 

 matter. 



When a steel spring is bent or distorted, what is it that is 

 really strained? Not the atoms the atoms are only dis- 

 placed; it is the connecting links that are strained the 

 connecting medium the ether. Distortion of a spring is 

 really distortion of the ether. All strain exists in the 

 ether. Matter can only be moved. Contact does not exist 

 between the atoms of matter as we know them ; it is doubt- 



