Q. E. D. | Page 8

ENERGY
I
What has been regarded by many as the greatest scientific triumph of
modern times was worked out about the middle of the last century by
James Prescott Joule and others, in determining that a certain amount of
mechanical energy is exactly equivalent to a definite amount of heat.
With this mechanical equivalent of heat all the various other forms of
energy have also been correlated; until now we have the general law of
the Conservation of Energy, which says that energy can be neither
manufactured nor destroyed, but merely transformed and directed. And
this magnificent law, like that of the conservation of matter, is strong
evidence that there must have been a real Creation at some time in the
long ago, different not merely in degree but in kind from anything
known to modern science.
Joule worked out the mechanical equivalent of heat by means of his
now famous experiment of churning water. He reasoned that if the heat
produced by friction, etc., is really energy in another form, then the
same amount of heat must always be generated by the expenditure of a
given amount of motion or mechanical work. And this must be true, no
matter whether this work is expended in overcoming the friction
between wood on wood, iron on iron, or in any other conceivable way.

Accordingly, he devised an experiment in which paddle wheels were
made to rotate in a vessel of water by means of falling weights
somewhat like the weights of a clock. The amount of work represented
by the falling of the weights was easily calculated, and so was the
amount of rise in temperature of the water caused by the friction of the
water with the rotating paddle wheels. In various other ways he
measured the amount of heat generated by a measured amount of work;
and as the result of all his experiments (with very slight corrections
made since by means of more exact apparatus), we now know that 778
foot pounds of work produce heat enough to raise one pound of water
one degree Fahrenheit; or stated in the metric system, 427 kilogram
meters of work will produce a calorie of heat.
Since these record-making experiments by Joule, the matter has been
verified over and over again in all sorts of ways; and almost every kind
of display of energy has been measured with more or less exactness.
Even the amount of food oxidized in the human body is now known to
be capable of correlation with the other forms of energy, though
necessarily very minute exactness of measurement is scarcely
attainable in this case. But no scientist of to-day doubts that all the
physiological processes of animals or of plants conform exactly to the
law of the conservation of energy that energy is neither created nor
destroyed by any means known to science. In other words, the amount
of energy in our world, if science can at all determine such a matter,
seems to be _a fixed quantity_, gradually being dissipated into space, it
is true, but momently replenished from the sun at exactly the same rate
now as hundreds or thousands of years ago. And while this energy is in
our world it is always capable of exact correlation in all of its
multitudinous forms, and is transformable back and forth without
increase and without loss.
On the discovery of the radioactive substances in 1896, some persons
hastily concluded that the law of the conservation of energy was
contradicted by the astonishing way in which these substances acted.
But further and more accurate experiments have set this matter at rest,
as indeed might have been expected; for the law of gravitation itself is
not more immovably established in the make-up of the universe than
this magnificent law that energy cannot be created by any means which
we call natural.

In all ages there have been men who have spent their lives in the vain
effort to invent a machine out of which work could constantly be
obtained without the expenditure upon it of an equal amount of work.
But the United States patent office has got so tired of receiving
applications for patents based on this idea of perpetual motion that they
have long since refused to issue any such patent where this principle is
the manifest object; and I suppose the governments of other countries
have taken a similar stand. And why? Because they know that energy
cannot now be created by any device, no matter how ingenious; and
they refuse to become a party to any scheme that seems to imply that
this modern creation of energy is within the bounds of possibility.
Yet what is all this but a confirmation of the declaration long ago made
that "the works were finished from the foundation