n. I venture to premise, from a careful
consideration of these three truths, that we shall be able logically and
philosophically to arrive at the simple, yet grand truth which reveals
the physical source of all motion of the universe.

CHAPTER VI

HEAT IS MOTION

ART. 60. _Heat is Motion._--On the phenomena of Heat, Newton in his
eighteenth query in _Optics_ asks the questions: "Is not the heat of a
warm room conveyed through the vacuum by the vibrations of a much
subtler medium than air, and is not the medium the same as that medium
by which light is reflected and refracted, or by whose vibrations light
communicates heat to bodies? And do not the vibrations of this medium in
hot bodies, contribute to the intenseness and duration of their heat?
And do not hot bodies communicate their heat to contiguous cold ones by
the vibrations of this medium propagated from them into the cold ones?
And is not this medium exceedingly more rare and subtle than air, and
exceedingly more elastic and active?" Thus it can be seen that Newton
was of the opinion that heat consists in a minute vibratory motion of
the particles of bodies, and that such motion was communicated through
what he calls a vacuum by the vibrations of an elastic medium, the
Aether, which was also concerned in the phenomena of light.

One of the first experimental investigations into the real nature of
Heat was made in 1798 by Count Rumford.

While he was engaged in boring brass cannon in the arsenal at Munich, he
was struck with the degree of heat which the brass gun acquired, and
with the still more intense heat which the metallic chips, which were
thrown off, possessed. Of the phenomena he says: "The more I meditated
on these phenomena, the more they appeared to me to be curious and
interesting. A thorough investigation seemed even to bid fair to give us
a farther insight into the hidden nature of Heat." Rumford therefore set
himself to find out by actual experiments what the nature of Heat was.
For this purpose he constructed a cylinder, and mounted it so that it
could be made to rotate by horse-power. At the beginning of the
experiment the thermometer stood at 60 deg. Fahrenheit, and after
half-an-hour, when the cylinder had made 900 revolutions, the
temperature was found to be 130 deg. Fahrenheit, so that there had been
an increase in the temperature of the cylinder of 70 deg. Fahrenheit.
The