m, of every body, attracts every other atom, both
of its own and of every other body, with a force which varies inversely
as the squares of the distances between the attracting and attracted
atom._--Here, indeed, a flood of suggestion bursts upon the mind.

But let us see distinctly what it was that Newton _proved_--according to
the grossly irrational definitions of _proof_ prescribed by the
metaphysical schools. He was forced to content himself with showing how
thoroughly the motions of an imaginary Universe, composed of attracting
and attracted atoms obedient to the law he announced, coincide with
those of the actually existing Universe so far as it comes under our
observation. This was the amount of his _demonstration_--that is to say,
this was the amount of it, according to the conventional cant of the
"philosophies." His successes added proof multiplied by proof--such proof
as a sound intellect admits--but the _demonstration_ of the law itself,
persist the metaphysicians, had not been strengthened in any degree.
"_Ocular_, _physical_ proof," however, of attraction, here upon Earth,
in accordance with the Newtonian theory, was, at length, much to the
satisfaction of some intellectual grovellers, afforded. This proof arose
collaterally and incidentally (as nearly all important truths have
arisen) out of an attempt to ascertain the mean density of the Earth. In
the famous Maskelyne, Cavendish and Bailly experiments for this purpose,
the attraction of the mass of a mountain was seen, felt, measured, and
found to be mathematically consistent with the immortal theory of the
British astronomer.

But in spite of this confirmation of that which needed none--in spite of
the so-called corroboration of the "theory" by the so-called "ocular and
physical proof"--in spite of the _character_ of this corroboration--the
ideas which even really philosophical men cannot help imbibing of
gravity--and, especially, the ideas of it which ordinary men get and
contentedly maintain, are _seen_ to have been derived, for the most
part, from a consideration of the principle as they find it
developed--_merely in the planet upon which they stand_.

Now, to what does so partial a consideration tend--to what species of
error does it give rise? On the Earth we _see_ and _feel_, only that
gravity impels all bodies towards the _centre_ of the Earth. No man in
the common walks of life could be _made_ to see or to feel anything
else--could be made to