CHAPTER 3 THE FIRST LAW
3.7 SHAFTWORK 85
BIOGRAPHICAL SKETCH
James Prescott Joule (1818–1889)James Joule drove the final nails into the cof-
fin of the caloric theory by his experimental
demonstrations of the mechanical equivalent
of heat.
Joule (pronounced like “jewel”) was born
in Salford, near Manchester, England. His fa-
ther was a prosperous brewery owner; after his
death, James and one of his brothers carried on
the business until it was sold in 1854.
Joule was a sickly child with a minor spinal
weakness. He was tutored at home, and at the
age of 16 was a pupil of the atomic theory ad-
vocate John Dalton.
As an adult, Joule was a political conser-
vative and a member of the Church of Eng-
land. He dressed plainly, was of a somewhat
nervous disposition, and was a poor speaker.
He was shy and reserved unless with friends,
had a strong sense of humor, and loved nature.
Joule never attended a university or had a
university appointment, but as an “amateur”
scientist and inventor he published over 100
papers (some of them jointly with collabo-
rators) and received many honors. He in-
vented arc welding and a mercury displace-
ment pump. He carried out investigations on
electrical heating and, in collaboration with
William Thomson, on the cooling accompany-
ing the expansion of a gas through a porous
plug (the Joule–Thomson experiment). The
joule, of course, is now the SI derived unit of
energy.
Joule’s best-known experiment was the de-termination of the mechanical equivalent of
heat using a paddle wheel to agitate water (Sec.
3.7.2and Prob. 3. 10 ). He reported his results in
1845, and published a more refined measure-
ment in 1850.a
In a note dated 1885 in hisCollected Pa-
pers, Joule wrote:
It was in the year 1843 that I read a paper “On
the Calorific Effects of Magneto-Electricity and
the Mechanical Value of Heat” to the Chemical
Section of the British Association assembled at
Cork. With the exception of some eminent men
... the subject did not excite much general at-
tention; so that when I brought it forward again
at the meeting in 1847, the chairman suggested
that, as the business of the section pressed, I
should not read my paper, but confine myself to a
short verbal description of my experiments. This
I endeavoured to do, and discussion not being
invited, the communication would have passed
without comment if a young man had not risen
in the section, and by his intelligent observations
created a lively interest in the new theory. The
young man was William Thomson, who had two
years previously passed the University of Cam-
bridge with the highest honour, and is now prob-
ably the foremost scientific authority of the age.
The William Thomson mentioned in Joule’s
note later became Lord Kelvin. Thomson de-
scribed introducing himself to Joule after the
1847 meeting, which was in Oxford, as a re-
sult of which the two became collaborators and
life-long friends. Thomson wrote:b
Joule’s paper at the Oxford meeting made a great
sensation. Faraday was there and was much
struck with it, but did not enter fully into the new
views. It was many years after that before any of
the scientific chiefs began to give their adhesion.
According to a biographer:c
His modesty was always notable. ‘I believe,’ he
told his brother on 14 Sept. 1887, ‘I have done
two or three little things, but nothing to make a
fuss about.’ During the later years of his life he
received many distinctions both English and for-
eign.
aRef. [ 84 ]. bRef. [ 17 ]. cRef. [ 66 ].