﻿284 Prof. J. Bay ma on the Fundamental 



cules, of a change by which the conditions of the molecular 

 equilibrium have been violated. Hence, before we speak of a 

 possible generation of heat and electric currents in the move- 

 ment of a planet through a resisting medium, we must admit 

 the full efficiency of the impact in retarding the motion of the 

 molecules directly exposed to the resistance of the medium. 

 The generation of heat and electric currents may, or even must, 

 follow, according to the assumption : but that which follows can- 

 not entail the least decrease of intensity in the retardation which 

 precedes, and of which it is the result. 



Professor Norton here employs a second argument. He says: 



"Again, if the action of gravity be not instantaneous, it will take 

 effect in a direction slightly inclined to the radius vector, and, in the 

 existing state of the planetary system, the tangential component 

 resulting from this inclination may be in equilibrium with the feeble 

 overplus of resistance from the aether." 



To this I answer (1) that, if luminiferous aether is supposed to 

 be repulsive, the study of the phenomena of light leaves no 

 room whatever for any hypothesis implying that such sether op- 

 poses a feeble resistance. This I have proved in my ' Molecular 

 Mechanics ' (pp. 176-180). As to the overplus, I have shown 

 just now that it would be the whole of the resistance. (2) That 

 the hypothesis concerning the successive propagation of the action 

 of gravity is utterly false, as I have fully shown in my work 

 (pp. 63-65), and has no other foundation than the confusion of 

 two things perfectly different, viz. action and motion, cause and 

 effect. (3) That, independently of the two preceding remarks, 

 and granting (only for the sake of the argument) that the said two 

 assumptions might be admitted, it would still be false that the 

 action of gravity " will take a direction slightly inclined to the 

 radius vector }> and have "a tangential component." The case 

 of gravitation is not parallel to that of the aberration of light, as 

 Professor Norton's argument seems to imply. Gravitation in- 

 vests continually the whole mass of the planet, and its resultant 

 passes through the centre of it : hence no tangential component 

 of gravitation is conceivable consistently with the received prin- 

 ciples of general mechanics. 



The learned Professor, after the two arguments hitherto ex- 

 amined, gives a third which consists of a retorsion of my diffi- 

 culty against my own explanation : 



" Besides, the supposed difficulty is not removed by substituting 

 an attractive for a repulsive sether. It is true that when a molecule 

 of the earth's mass encounters an atom of the sether on the line of its 

 advance, it will, upon Professor Bayma's idea, pass through it and 

 leave it behind ; but he has failed to note the fact that, during the 



