CHAPTER 3 THE FIRST LAW
3.2 SPONTANEOUS, REVERSIBLE,ANDIRREVERSIBLEPROCESSES 63
BIOGRAPHICAL SKETCH
Benjamin Thompson, Count of Rumford (1753–1814)Benjamin Thompson, whose career was re-
markably varied and colorful, collected exper-
imental evidence of the falseness of the caloric
theory—the concept that heat is a material sub-
stance. He was a complex man: energetic, ego-
tistical, domineering, and misanthropic.
Thompson was born into a farming fam-
ily in Woburn, Massachusetts. He married a
wealthy widow and was admitted into fashion-
able society. At the time of the American Rev-
olution he was accused of being a loyalist, and
at the age of 23 fled to England, abandoning
his wife and daughter. He was an Under Sec-
retary of State in London, returned briefly to
America as a British cavalry commander, and
then spent 11 years as a colonel in the Bavar-
ian army. In Bavaria, to reward his success in
reorganizing the army and reforming the so-
cial welfare system, he was made a Count of
the Holy Roman Empire. He chose the name
Rumford after the original name of Concord,
New Hampshire, his wife’s home town.
While in Bavaria, Count Rumford carried
out the cannon-boring experiments for which
he is best known. The caloric theory held that
heat is a kind of indestructible fluid (“caloric”)
that is held in the spaces between the atoms
of a body. Frictional forces were supposed
to cause a rise in temperature by squeezing
caloric fluid out of a body. Rumford’s experi-
ments involved boring into a horizontally-fixed
cannon barrel with a blunt steel bit turned by
horse power. He reported the results in 1798:aBeing engaged, lately in superintending the bor-
ing of cannon, in the workshops of the military
arsenal at Munich, 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 exper-
iment,) of the metallic chips separated from it by
the borer...
By meditating on the results of all these ex-
periments, we are naturally brought to that great
question which has so often been the subject of
speculation among philosophers; namely,
What is Heat?—Is there any such thing as an
igneous fluid?—Is there any thing that can with
propriety be calledcaloric?...
And, in reasoning on this subject, we must
not forget to consider that most remarkable cir-
cumstance, that the source of the heat generated
by friction, in these experiments, appeared evi-
dently to beinexhaustible.
It is hardly necessary to add, that any thing
which anyinsulatedbody, or system of bod-
ies, can continue to furnishwithout limitation,
cannot possibly be amaterial substance: and it
appears to me to be extremely difficult, if not
quite impossible, to form any distinct idea of any
thing, capable of being excited and communi-
cated, in the manner the heat was excited and
communicated in these experiments, except it be
MOTION.
Rumford thought of heat in a solid as har-
monic vibrations similar to acoustic waves, not
as random motion or as a form of energy as
later developed by James Joule.
Rumford also made investigations into bal-
listics, nutrition, thermometry, light, and fabric
properties. He invented the Rumford fireplace
and the drip coffee percolator. After living in
London for fourteen years, he settled in Paris
in 1804. The following year, his first wife hav-
ing died in America, he married the widow of
the famous French chemist Antoine Lavoisier.
The marriage was stormy and they soon sepa-
rated.aRef. [ 147 ].