Messrs. F. A. E. and Em. Keller, in a joint "Memoir on the Cause of Weight, and of the Effects Attributed to Universal Attraction," (presented to the French Academy of Sciences March 23, 1863,) announced as the motive force the agency of aetherial undulations. Referring the effect to the longitudinal vibrations of the aether, the writers think " the time has come to seek and to find a plausible explanation of weight — simple and natural — in the ceaseless action of these waves on resisting bodies, an action analogous to that of ocean-waves, which drive ships upon the coast by the vis viva of their flow over that of their ebb ; for the longitudinal vibrations of the aetherial waves condensing and dilating being simply impulsions followed by reaction, and the reactions being always more feeble than the impulsions, there follows definitively an excess of force in the direction of the propagation which should communicate itself to dense bodies opposed to their propagation, and which should press them one toward the others. It is thus that inert bodies of slight density would transmit their impulsion to denser bodies, when thrown promiscuously into a long box, were we to strike repeatedly one of the ends of the box. Ultimately the denser particles will collect at the opposite end ; and if both ends are struck simultaneously these particles will collect in the middle of the box, while the others will be arranged in the order of decreasing density from the center."
After considering the effect on a line of particles subjected to continuous shocks at each extremity, the writers proceed : " If instead of a single line of particles a certain volume be taken, and if instead of shocks in two opposite directions the shocks are supposed to be given in all directions, it is easy to see that the denser particles, mutually absorbing a part of the impulses directed from one to the other, would approach as if [258] really attracted. As a resultant of all the impressions, the particles would act upon each other in the inverse ratio of the square of the distance, and in the direct ratio of their number, — an action which at once presents a striking analogy with the law of universal attraction."[1]
It is not believed that either of these ratios would be even approximately attained. It will be observed that in this scheme the aetherial vibrations are supposed to exert a precisely opposite action to the undulations exhibited in the system of Professor Challis, having their origin on the circumferences of enormous spheres of aether, and being accurately directed to a central point or points, whatever may be the variety of distribution or the changes of position in the material elements.
- ↑ Comptes Rendus, vol. lvi, pp. 531, 532.