196 Prof. Norton on Molecular Physics. 



3. A third molecular force, then, consists of a series of repul- 

 sive or outward-acting impulses imparted to the universal aether 

 at the surface of the atom of a molecule by the contractile force 

 exerted by the atom upon its electric atmosphere. This repul- 

 sion is equal, at its origin, to the attraction which developes it. 

 It is propagated in waves which, unlike the waves conveying the 

 other molecular forces, proceed through the universal aether. 

 These waves, if each contraction of the atmosphere were not fol- 

 lowed by a partial expansion, would be of the character of " waves 

 of translation/'' and would convey only outward-acting impulses ; 

 they are, in fact, oscillatory waves, in which the outward predo- 

 minate over the inward acting-impulses. 



The force thus originating may be regarded as the primary 

 force of heat, and may be termed heat repulsion. The other two 

 molecular forces may be designated as the forces of electric attrac- 

 tion and electric repulsion. But they should not be confounded 

 with the special electric forces that come into play whenever the 

 natural quantity of electric aether associated with atoms, or 

 present on different sides of atoms, experiences any material 

 increase or diminution — which will be considered in another 

 connexion. 



The molecular forces that have now been specified might be 

 otherwise characterized as follows: (1) A repulsion of the one 

 electric atmosphere for the other, operating through the inter- 

 vention of the electric aether posited between the two. (2) An 

 attraction of the gross atom of the one molecule for the electric 

 atmosphere of the other, also taking effect by means of the in- 

 tervening electric aether. (3) A repulsion exerted by the atom 

 of the one molecule upon that of the other, through the inter- 

 vening universal aether, and originating in the attraction just 

 mentioned. These forces consist of recurring impulses propa- 

 gated in waves through the aethereal media, which take effect 

 ultimately as attractive or repulsive impulses upon the central 

 atoms of molecules. The law r of diminution of the propagated 

 forces is that of the inverse squares. 



If the (Ethereal as well as the electric atmospheres of particles 

 be conceived to be in a state of dynamical equilibrium, their 

 alternate contractions and expansions should originate oscilla- 

 tory waves that would be propagated indefinitely onward through 

 the aether of space. If we admit, with Professor Challis, that 

 such purely oscillatory waves, when they fall upon particles, 

 will give rise to an attraction or a repulsion, according to the 

 breadth of the waves in comparison with the diameter of the 

 particles, and that the force of gravitation may be conveyed by 

 such waves, we have in the supposed dynamical condition of 

 aethereal atmospheres of particles a possible origin of waves of 



