272 



Essay on Motion and Force. 



able by artificial means. The fact that they can be thus sep- 

 arated, taken in connection with this well established law of 

 attraction, is conclusive to my mind that they do never come 

 into direct contact. Now, when the terms action and re- 

 action are used, what idea is desired to be conveyed ? 

 Two bodies approach each other, and when they have 

 reached a certain point of approximation, they coincidently 

 recede ; this is the phenomena to which we desire to give 

 a name. Do these co-relative terms action and reaction 

 properly connote the facts? They, too, are the offshoots ot 

 wrong notions of motion and force, and, I think, stand di- 

 rectly in the path of advancement. It is from the ob- 

 jectional mode of viewing the several phenomena which it 

 is sought to characterize by them, that the theory of media 

 as being necessary to the propagation of force, has been 

 derived. This theory I am well aware is not to berashly 

 opposed, advocated as it is so universally, and by such think- 

 ers as Xewton and others no less profound. Yet I cannot 

 but dissent from it and I do so in the following general 

 terms. TSTo medium is essential for the transmission of 

 motion. 



To supply a medium for the propagation of force the 

 hypothesis of an all-permeating imponderable ether has 

 been called in, which, like the idea of occult force, has 

 stood prominently forth in the teachings of philosophers 

 of past and present times. The tendency of the present 

 age is, undoubtedly, to discard such hypotheses, and to 

 view all physical phenomena as material manifestations ; 

 so that while the doctrine of a medium, as essential to the 

 transmission of motion, is still adhered to, the medium is 

 supposed to be ordinary matter in a state of extreme 

 tenuity, yet possessing the essential attributes of matter as 

 ponderability, extension and so forth, the undulation of 

 which transmits motion to bodies remote from the sources 

 of motion. Thus light heat, &c., are supposed to be trans- 

 mitted. 



Now if the interplanetary matter be, as Grove and 



