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able conditions, generated and maintained by the Will and Power of the 
Creator of the Universe. It never occurred to me to imagine the existence 
of any power which could prevent the Originator and Upholder of these 
conditions from withdrawing them, or altering them, at His will. 
I now proceed to the main purpose of the remarks, which is, to meet the 
argument, accepted by the Lord O’Neill, by which Mr. Herbert Spencer 
maintains that the consideration of what is called “ action at a distance ” is 
not got rid of by the action of the aethereal medium assumed to be atomically 
constituted in the manner already stated. In the first place, I do not admit 
that any argument respecting the relative magnitudes of the atoms of the 
aether and the spaces separating them can be drawn from the imponderability 
of the aether, because I hold that the weights of all bodies are due to the 
action of the.aether upon them, and consequently that neither weight nor 
non-weight can be predicated of the constituents of the aether itself. The 
aether, for instance, does not gravitate towards the mass of the sun, because 
it is by the intervention of the aether that the sun attracts. Thus the argu- 
ment for the reality of action at a distance based on the supposition that 
the aether is imponderable falls to the ground. 
In my scientific productions, published in the Philosophical Magazine , I 
am wholly at issue with Mr. Herbert Spencer and most modern physicists 
as to the possibility of one atom of matter acting upon another by mere 
emanation of force, without the intervention of mediate substance, and in 
this view I am supported by the recorded opinion of Newton, who thought 
that no one competent in philosophy could entertain such an idea. I have 
in fact argued, I think with some success, that all the physical forces recog- 
nised by experiment, including the molecular forces by which the atoms of 
sensible bodies are held together so as to constitute masses, are effects of 
mutual actions between the aether supposed of invariable intrinsic elasticity, 
and atoms supposed to be inert, movable, and of constant spherical form 
and magnitude, and that on these suppositions the effects admit of being 
ascertained by mathematical calcuUtions.’ According to these premises the 
action of one atom on another is shown to be produced by means either of 
propagated vibrations or of currents of the aether, so as to exclude action 
at a distance. It may, however, be urged that such action must still take 
place between the atoms of the aethereal medium in order to account for its 
pressure. To meet this objection it occurred to me, in my first speculations 
on the nature of physical force, that as the law connecting pressure with 
density in air of given temperature might be shown to be the result of mutual 
action by pressure between the aerial atoms and the aether, the same law might 
be supposed to be produced in the aether itself by like action of another aether 
of still greater tenuity ; and so on ad libitum. This idea of successive (ethers 
which, probably, would be received with favour by those who adopt material- 
istic views, I shortly afterwards discarded ; and in place of it I now propose 
the following theory, which, I think, may be considered to give a reasonable 
account of the origin and character of physical force. To render the theory 
intelligible I begin with an illustrative instance. The production of phe- 
