Prof. Norton on Molecular Physics. 199 



motion of atoms of ordinary matter in which this wave convey- 

 ing such wonderfully rapid vibrations can have originated. We 

 at the same time remove the necessary foundation for the 

 explanation of a variety of special facts and phenomena, which 

 require the assumption of special rates of vibration, proper 

 to the particles of different bodies — as the different colours of 

 bodies, &c. 



Again, if the rates of vibration of ultimate particles depend 

 upon the mutual actions subsisting between the displaced par- 

 ticle and those adjacent to it, the vibrations in which the heat- 

 force is supposed to consist, should be propagated from par- 

 ticle to particle, just as any mechanical force is; in other 

 words, heat should be conducted after the same manner, es- 

 sentially, and at the same rate, that sound is conducted by the 

 same medium. 



By ascending to the reservoir of primary force, from which 

 all the different streams of force flow, as has been attempted in 

 this communication, we may avoid some of the difficulties at- 

 tending the rejection of the idea of the existence of an electric 

 gether; and in many portions of the field of physical science 

 the part played by the electric aether is so similar to that which 

 we may suppose would be performed by the universal aether 

 under similar circumstances, that the suspicion at times arises 

 that all the offices now attributed to the former will eventually 

 be found to be discharged by the latter. If so, the processes of 

 operation will not of necessity be changed, but only the agent 

 or medium. 



Admitting that the molecular forces consist of two forces of 

 repulsion and one of attraction, as characterized on pp. 195-6, let 

 us proceed to inquire into the variations that may occur in the 

 effective action of two similar molecules, separated by various 

 intervals of distance. Let x— the distance between two mole- 

 cular atmospheres ; r= the radius of either atmosphere ; m = the 

 constant of electric repulsion, that is, the force of electric repul- 

 sion exerted upon either atom when x= 1 ; and rc=:the con- 

 stant of the electric attraction, which will also be the constant of 

 the equal force of repulsion propagated from the surface of the 

 atom through the universal aether. Also let u— the force of 

 electric repulsion, and v= the excess of the attractive force over 

 the sethereal repulsion developed by the attraction, — all the forces 

 being considered as taking effect upon the central atom. The 

 effective action exerted by either molecule upon the other will 

 be the difference between the values of u and v. Denote it by 

 /; then f=v— u. When the calculated value of /is positive 

 the action will be attractive ; when it is negative the action will 

 be repulsive* We have for the force of attraction the general 



