ed so that the light passed it longitudinally. Ten
minutes' exposure was sufficient to make it decidedly magnetic. Hence I
infer that the motions which we call magnetic attractions and repulsions
may be quite analogous to such helical motions; also, that these motions
exist in ether, and evidently may be either right-handed or left-handed.
Wind up on a pencil a piece of wire twelve or fifteen inches long,
making a loose spiral. Bring the two ends of the spiral together; and
note first that one is twisted to the right, the other to the left. If
they be twisted into each other, they will advance very easily; but if a
right-handed spiral were to be interlocked with another like it, and
both turned in the direction of their spiral, they would separate
rapidly. Applying this conception to a magnet, we might suppose that
such spiral motions will be set up in the ether by the magnet, and that
such motions re-acting upon ordinary matter affect it as attraction and
repulsion; and thus we should have at least a conceivable mechanical
explanation of the phenomenon.

[Illustration: FIG. 5.]

There are numberless experiments which might be given to further exhibit
the relation of mass motion to magnetism, but a single one more must
suffice. No rotation of a magnet upon its own axis can produce any
effects upon a current that is exterior to it; but if a loop of wire be
kept stationary adjacent to a magnet, as in Fig. 5, while the magnet
revolves, a current of electricity is produced; and if the magnet be
kept stationary, and the loop revolves, a current will also be produced,
but in the opposite direction. Here, as in all the other cases, no
electricity is originated, save when motion is imparted to one or other
of the parts. This experiment is due to Faraday.

From all these cases we can come to but one conclusion, that both
electricity and magnetism are but forms of motion; electricity being a
form of motion in ordinary matter, for it cannot be made to pass through
a vacuum, while magnetism must be a form of motion induced in the ether,
for it is as effective in a vacuum as out of it; electricity always
needing some material conductor, magnetism needing no more than do
radiant heat and light.

VELOCITY.

Measurements have been made of the velocity of electricity; both that of
high tension, such as the spark from a Leyden jar, and also that from a
battery. The former was found to have a velocity over 200,000 miles a
second,