466 Dr. Boase on M. Faye's Memoir on the Existence of a 



no other than a retrograde movement in science. If any force 

 can be said to act at a distance, it surely may be supposed to be 

 that of electricity, for it has all the outward appearance of such 

 an action j but Faraday's elaborate and searching inquiry into 

 all the obscure conditions of the case has established beyond 

 dispute that there is a communication of this force from mole- 

 cule to molecule by the process of induction. M. Faye need 

 not search after a perfect vacuum in which to perform experi- 

 ments for proving the action of repulsive force at a distance ; for 

 the sodium he employs in removing the residue of oxygen after 

 mechanical exhaustion will fill it with highly elastic vapour, the 

 presence of which may be demonstrated by an electric discharge j 

 and indeed the very electric incandescence will also fill the ves- 

 sel with the vapour of the metallic poles, to say nothing of the 

 ■aether of space, for this is the point in dispute ; but surely if 

 that aether be the means of transmitting radiant heat from the 

 sun to all its planets, it must also be sufficient within an ex- 

 hausted vessel. It does not, however, very clearly appear that 

 M. Faye directly disputes luminous and calorific radiations ; for 

 he says that his radial repulsive force is exercised in the same 

 manner, and that it is in all its properties identical with phy- 

 sical heat. If it be that which radiates from incandescent sur- 

 faces, it can be no other than radiant heat ; it only remains to de- 

 cide its modcj of operation through space and other diathermanous 

 media. Newton was decidedly opposed to the actio in distans j 

 for in his third letter to Bentley he observes, " That one body may 

 act upon another at a distance through a vacuum without the 

 mediation of anything else, by and through which their action 

 and force may be conveyed from one to another, is to me a great 

 absurdity." 



In the pursuit of science, the Only legitimate method is to pro- 

 ceed from the known to the unknown. We know that in the 

 case of a series of suspended ivory balls, the ball at one extremity 

 will be put in motion by raising and letting fall the ball at the 

 other extremity : here we have a visible and tangible medium 

 through which force is transmitted, and by removal of which the 

 extreme balls cannot affect each other. So in the electric tele- 

 graph, we know that force applied at one end of the conducting 

 wire will produee motion at the other, but its transmission 

 depends on the presence of the intervening medium. When, 

 therefore, in experiments on radiant heat, we find that this 

 force will affect bodies at a distance from its source, even 

 through diathermanous screens, it is a legitimate inference that 

 this must also take place through an appropriate medium, even 

 though it be not tangible or visible. Such a medium has beeo 

 acknowledged as adequate to the transmission .of light by the 



