I9I4-] "A KINETIC THEORY OF GRAVITATION." 119 



is the sum of the shadows of its constituent parts. The energy 

 shadows of two gravitating bodies interblend, so that the energy 

 density between them is less than elsewhere, and they are pushed 

 toward each other by the superior energy density, or wave pressure, 

 on the sides turned away from each other. 



That the ether really is endowed with vast intrinsic energy in 

 some form or forms is the belief of many eminent physicists, and 

 it seems to me highly probable that all energy has its source and 

 destination in the ether ; that is to say, that energy in all the various 

 forms in which we observe it, comes in some w^ay from the ether and 

 is energy of the ether. This view does not in any manner conflict 

 with the principle of conservation of energy. 



In support of my contention that etherial energy is the cause and 

 essence of gravitation, I wish to emphasize particularly, what seems 

 to me an obvious fact, that the energy acquired by a falling body 

 comes from the ether, and is restored to the ether when that body 

 undergoes negative gravitational acceleration. 



In this connection I cannot do better than quote Lord Kelvin's 

 description of the collision of two very large bodies through the influ- 

 ence of gravitation. In his " Popular Lectures and Addresses " 

 (\"ol. I, 413-417) he says: 



" To fix the ideas think of two cool solid globes, each of the same 

 mean density as the earth and half the sun's diameter, given at rest, 

 or nearly at rest, at a distance asunder equal to twice the earth's 

 distance from the sun. They will fall together and collide in exactly 

 half a year. The collision will last for about half an hour, in the 

 course of w^hich they will be transformed into a violently agitated 

 incandescent fluid mass flying outward from the line of motion 

 before the collision and swelling to a bulk several times greater than 

 the sum of the original bulks of the two globes. . . . The time of 

 flying out would probably be less than half a year when the fluid 

 mass must begin to fall in again towards the axis. In something 

 less than a year after the first collision the fluid will again be in a 

 state of maximum crowding towards the center, and this time even 

 more violently agitated than it was immediately after the first col- 

 lision ; and it will again fly outward, but this time axially towards the 

 places whence the two globes fell. It will again fall inwards, and 



