6 2 FRAGMEN TS OF SCIENCE.
be an attraction. Newton pondered all these things. ‘He
had a great power of pondering. He could look into the
darkest subject until it became entirely luminous. How
this light arises we cannot explain; but, as a matter of
fact, it does arise. Let me remark here, that this power of
pondering facts is one with which the ancients could be
but imperfectly acquainted. They found the uncontrolled
exercise of the imagination too pleasant to expend much
time in gathering and brooding over facts. Hence it is that
when those whose education has been derived from the
ancients speak of “the reason of man,” they are apt to
omit from their conception of reason one of its greatest
powers. Well, Newton slowly marshalled his thoughts, or
rather they came to him while he “intended his mind,”
rising one after another like a series of intellectual births
out of chaos. He made this idea of attraction his own.
But to apply the idea to the solar system, it was necessary
to know the magnitude of the attraction and the law of its
variation with the distance. His conceptions ﬁrst of all
passed from the action of the earth as a whole, to. that of
its constituents particles, the integration of which composes
the whole. And persistent thought brought more and
more clearly out the ﬁnal divination, that every particle of
matter attracts every other particle by a force which varies
inversely as the square of the distance between the par-
ticles. This is Newton’s celebrated law of inverse squares.
Here we have the ﬂower and outcome of his induction; and
how to verify it, or to disprove it, was the next question.
The ﬁrst step of Newton in this direction was to prove,
mathematically, that if this law of attraction be the true
one; if the earth be constituted of particles which obey
this law; then the action of a sphere equal to the earth in
size on a body outside of it, is the same as that which
would be exerted if the whole mass of the sphere were
contracted to a point at its centre. Practically speaking,