98 Prof. Norton on Molecular Physics. 



upon the same by the entire atmosphere. The centres of repul- 

 sion and attraction will also be coincident, and the law of varia- 

 tion of the two forces will be the same ; hence beyond the limits 

 of the atmosphere there will be no effective action exerted 

 by the molecule upon any electric aether that may be posited 

 there. But the notion that there is no interception of force 

 does not accord with the fundamental idea of the propagation 

 of force by the universal aether (p. 96). It is impossible that a 

 propagated force of repulsion should, take effect upon an ato- 

 mette of electric sether, unless the universal aether, which is the 

 medium of propagation, be in some degree condensed upon the 

 surface upon which the wave-force falls. Such condensation must 

 give rise to a reflex wave, and the dispersion of a certain amount 

 of force into the surrounding aether. Upon, the principle of the 

 conservation of force the amount of force thus dispersed must be 

 abstracted from the original wave-force. Now, if the atomettes 

 of the electric atmosphere intercept a certain portion of the re- 

 pulsion propagated from other atomettes, it follows that the 

 centre of repulsion of the whole atmosphere cannot be coinci- 

 dent with the centre of attraction, or centre of the atom of mat- 

 ter. It would seem also that the repulsive pulses propagated 

 from the atomettes should be more or less intercepted by the 

 central atom of the molecule, which should tend to displace the 

 centre of repulsion still more. For each side of the molecule 

 this centre must lie somewhere between the centre of the atom 

 and the surface of the atmosphere, as at r, fig. 4. In this state 

 of things the atmosphere will have a definite limit, Y\v. 4 



as before ; but beyond its limits, since its repulsion 

 must decrease more rapidly than the attraction, an 

 effective force of attraction will be exerted by the 

 entire molecule. As a consequence, the external 

 electric aether will be retained in contact with the 

 atmosphere, and press upon its surface with a cer- 

 tain force. Its density will decrease outward, and doubtless be- 

 come insensible at sensible distances. If then we confine our 

 attention to a single molecule, we perceive that it must consist 

 of an atom of ordinary matter surrounded with two envelopes 

 of electric aether ; of which the outer presses upon the inner, and 

 extends indefinitely, but becomes evanescent at a distance a cer- 

 tain number of times greater than the diameter of the inner en- 

 velope*. Hitherto, in speaking of the electric atmosphere of a 

 molecule, we have alluded only to the inner and principal enve- 

 lope, and have regarded the diameter of a molecule as the same 



* It is possible that in some cases the outer atmospheric envelope may 

 be made up of several spherical layers, separated by surfaces of no effective 

 molecular action. 



