assumes--that restless swinging from side to side? Is it a property
inherent in its own nature, or is it a power communicated to it from
without? There is a train of wheelwork enclosed with it in the case. Is
that the source of its vibratile mobility? Assuredly not. For if we
arrest its motion with our hand at the instant that its form hangs
perpendicularly suspended, that motion is not renewed although the
wheels remain in unaltered relation. Those mechanical contrivances
clearly do not comprise the secret of its swinging. We must look
elsewhere if we would ascertain the fundamental cause.

Has the reader ever looked at the plain white building, with successive
rows of little windows, which so often spans the breadth of our smaller
streams? If he has, the thought has at once arisen that within those
walls huge wheels and heavy-revolving stones remorselessly tear and
crush to powder heaps upon heaps of yellow grain, with a power that is
equal to the combined effort of a whole troop of horses concentred in
the task. But we question very much whether he has as clearly seen
whence those clattering wheels derive their many horse-power! If we were
to ask him to tell us how they acquired their rolling strength, he would
most probably answer--from the current of the stream. This reply would
amount to nothing in the matter of explanation; the force of the current
is as much a borrowed attribute as the force of the wheelwork. The
running water is no more an independent and living agent than is the
machinery which it turns. Beyond both is the one grand determining
influence--the attractive energy inherent in the substance of the vast
earth. This it is which makes the water run; this it is which enables
the running water to move the wheelwork inserted into its channel. As
the magnet draws to itself the fragment of steel, the earth draws to
itself all ponderable matter; and whenever ponderable matter is free to
move, it rushes as far as it can go towards the centre of the earth's