are
called heat, light, and chemical properties, is simply untrue. What a
ray will do, depends upon what kind of a structure it falls on; and when
it has done that work, of whatever kind it may be, it ceases to exist as
a ray.

If, therefore, electricity can directly produce light, it is simply
producing _motion_, as in the case of heat, the motion being of such a
sort that the eyes of men are affected by it.

4th, It can produce _magnetism_. A current of electricity passing
through a coil of wire makes such a coil a magnet, which will set itself
in the direction of the magnetic meridian of the earth; and, if a bar of
soft iron be placed in the coil, it becomes the familiar electro-magnet;
and, if hardened steel be put in it, it becomes a permanent magnet.

This leads to the inquiry as to what magnetism is. We know that it can
produce motion by its moving at a distance a piece of iron or another
magnet. It will also sustain a mass of matter against gravity or some
other contrary force. Through such mechanism as magneto-electric
machines it produces electricity in great abundance, which again can be
used to produce any of the effects of electricity,--moving bodies by
attraction or repulsion, generating heat or light, or again making a
magnet. But as all of these are but varied forms of motion, either of a
mass as a whole, or molecular, can it be doubted for an instant, that
what we call magnetism is but some form of motion? Must it not be either
some form of matter, or some form of motion? If it were a form of
matter, then a magnet would only be permanent so long as it was not
used; for use implies consumption of the force; and, if this be matter
in any form, then in a given mass of matter there can be but a definite
quantity of such magnetic matter, and consumption must lessen that
quantity. As a matter of fact, there is no perceptible lessening of the
power of a magnet when it is properly used. It is also a matter of fact,
that neither motion of a mass, nor electrical effects, nor any other,
can be produced by the action of a magnet alone. It is only when some
form of motion has been added to its own property, that we get any kind
of an effect from it: hence all effects due to its action are
_resultants_ of two forces, one of them being common motion of a mass of
matter, and the other the energy of the magnet. Hence we infer that a
magnet is a mechanism of such a structure as to change the direction and
character o