y lost by the other.

Energy is always found in association with matter, so that matter has
sometimes been termed the Vehicle of Energy. Wherever, therefore, we
find energy of any kind or sort, there we find matter also, as the two
are inseparably connected together. Thus, wherever we have heat, we have
matter in a particular state of motion, generally understood as
vibratory motion Wherever we have light, which is also a form of energy,
we also have matter in motion, that is the Aether, in a state of
periodic wave-motion; and wherever we have electricity, we have again
matter possibly in a state of rotatory motion, as we shall see later on.
Energy, therefore, is the power which a body possesses to do work.

ART. 52. _Conservation of Energy._--The principle of the Conservation of
Energy was first enunciated by Mayer in 1842. The principle may be
defined as follows: The total amount of all the energy, as light, heat,
electricity and magnetism, Gravitation, etc., in Nature is unchangeable;
so that, according to this law, the universe possesses a store of energy
which is unchangeable in quantity throughout all time. The energy may
pass from one form to another, yet the total amount ever remains the
same. It is almost unnecessary to say, that this is a principle which,
like the conservation of matter, is incapable of absolute proof, but its
assumption has greatly helped scientific thought and speculation from
time to time. Clerk Maxwell says (_Theory of Heat_) on this point: "The
total energy of any body is a quantity which can neither be increased
nor decreased by any mutual action of the bodies, though it may be
transformed into those forms of which energy is susceptible."

The conservation of energy is inseparably connected with the
conservation of matter (Art. 30). They cannot be divided, because, if
energy is only to be found in association with matter, then if the law
of the conservation of matter falls to the ground, the principle of the
conservation of energy falls with it. Energy, therefore, like matter,
cannot be destroyed or created by any process known to man. As there is
no process known, either in the chemical or in the physical world, by
which new matter may be created by man, so, in relation to energy of any
kind or sort, there is no process known by which man can create or even
destroy the smallest form of energy that exists. If energy appears in
any body or in any particular form, it is solely because o