CHAPTER 4 THE SECOND LAW
4.3 CONCEPTSDEVELOPED WITHCARNOTENGINES 114
BIOGRAPHICAL SKETCH
William Thomson, Lord Kelvin (1824–1907)William Thomson was born in Belfast, Ireland.
His mother died when he was six. In 1832 the
family moved to Glasgow, Scotland, where his
father had been appointed as the chair of math-
ematics at the University.
In 1845 Thomson was age 21. He had re-
cently graduated from Cambridge University
with high honors in mathematics, and was in
Paris for discussions with French physicists
and mathematicians. He had learned about
Carnot’s book from Clapeyron’s 1834 paper
but could not find a copy—no bookseller in
Paris had even heard of it. Nevertheless, the in-
formation he had was sufficient for him to real-
ize that Carnot’s ideas would allow a thermo-
dynamic temperature scale to be defined, one
that does not depend on any particular gas.
The following year, Thomson became the
Chair of Natural Philosophy at Glasgow Uni-
versity, largely through the influence of his fa-
ther. He remained there until his retirement in- His concept of a thermodynamic tem-
perature scale, his best-known contribution to
thermodynamics, was published in 1848.a
Thomson published other papers on the the-
ory of heat, but his ideas eventually changed
as a result of hearing a presentation by James
Joule at a meeting in Oxford in 1847. Joule
was describing his experiments with the con-
version of work to thermal energy by a paddle
wheel. In a letter written to his nephew, J. T.
Bottomley, Thomson wrote:b
I made Joule’s acquaintance at the Oxford meet-
ing, and it quickly ripened into a life-long friend-
ship.
I heard his paper read in the section, and
felt strongly impelled at first to rise and say
that it must be wrong because the true mechan-
ical value of heat given, suppose in warm wa-
ter, must, for small differences of temperature,
be proportional to the square of its quantity. I
knew from Carnot that thismustbe true (and itis
true; only now I call it ‘motivity,’ to avoid clash-
ing with Joule’s ‘mechanical value.’) But as I
listened on and on, I saw that (though Carnot
had vitally important truth, not to be abandoned)
Joule had certainly a great truth and a great dis-
covery, and a most important measurement to
bring forward. So instead of rising with my ob-
jection to the meeting I waited till it was over,
and said my say to Joule himself, at the end of
the meeting. This made my first introduction to
him. After that I had a long talk over the whole
matter at one of theconversazionesof the Asso-
ciation, and we became fast friends from thence-
forward.
The physicist Charles Everitt described
Thomson’s personality as follows:c
Thomson was the kind of man who created all
around him a sense of bustle and excitement.
... [He] was a man of violent enthusiasms. He
would take up a subject, work at it furiously for
a few weeks, throw out a string of novel ideas,
and then inexplicably drop everything and pass
on.
During his career, Thomson published more
than 600 papers and received many honors. In
addition to the theory of heat, his work in-
cluded a dynamical theory of electricity and
magnetism, and the invention of the mirror gal-
vanometer used as the telegraph receiver for
the first transatlantic submarine cables.
Thomson was the chief technical consultant
for the initial cable projects. As a result of
their success and his involvement in the con-
struction of a global cable network, he became
extremely wealthy and was knighted in 1866.
In 1892 he became Baron Kelvin of Largs.
“Kelvin” is the name of the river that flows past
Glasgow University, “Largs” is the town where
he had his home, andkelvinis now the SI unit
of thermodynamic temperature.
aRef. [ 89 ]. bRef. [ 17 ]. cRef. [ 51 ].