of being heated or cooled. He thought he had proved that heat is
only a form of motion.

His experiment for producing indefinite quantities of heat by friction
is recorded by him in his paper entitled, "Inquiry Concerning the Source
of Heat Excited by Friction."

"Being engaged, lately, in superintending the boring of cannon in the
workshops of the military arsenal at Munich," he says, "I was struck
with the very considerable degree of heat which a brass gun acquires in
a short time in being bored; and with the still more intense heat (much
greater than that of boiling water, as I found by experiment) of the
metallic chips separated from it by the borer.

"Taking a cannon (a brass six-pounder), cast solid, and rough, as it
came from the foundry, and fixing it horizontally in a machine used
for boring, and at the same time finishing the outside of the cannon by
turning, I caused its extremity to be cut off; and by turning down
the metal in that part, a solid cylinder was formed, 7 3/4 inches in
diameter and 9 8/10 inches long; which, when finished, remained joined
to the rest of the metal (that which, properly speaking, constituted the
cannon) by a small cylindrical neck, only 2 1/5 inches in diameter and 3
8/10 inches long.

"This short cylinder, which was supported in its horizontal position,
and turned round its axis by means of the neck by which it remained
united to the cannon, was now bored with the horizontal borer used in
boring cannon.

"This cylinder being designed for the express purpose of generating heat
by friction, by having a blunt borer forced against its solid bottom at
the same time that it should be turned round its axis by the force of
horses, in order that the heat accumulated in the cylinder might from
time to time be measured, a small, round hole 0.37 of an inch only in
diameter and 4.2 inches in depth, for the purpose of introducing a small
cylindrical mercurial thermometer, was made in it, on one side, in a
direction perpendicular to the axis of the cylinder, and ending in the
middle of the solid part of the metal which formed the bottom of the
bore.

"At the beginning of the experiment, the temperature of the air in the
shade, as also in the cylinder, was just sixty degrees Fahrenheit. At
the end of thirty minutes, when the cylinder had made 960 revolutions
about its axis, the horses being stopped, a cylindrical mercury
thermometer, whose bulb was 32/100 of an inch in diameter and 3 1/4