A Joule Sketch

Osborne Reynolds, who met Joule in 1869, gives us this impression of his manner
and appearance in middle age: “That Joule, who was 51 years of age, was rather
under medium height; that he was somewhat stout and rounded in figure; that
his dress, though neat, was commonplace in the extreme, and that his attitude
and movements were possessed of no natural grace, while his manner was somewhat
nervous, and he possessed no great facility of speech, altogether conveyed
an impression of simplicity, and utter absence of all affectation which had characterized
his life.”
Joule married Amelia Grimes in 1847, when he was twenty-nine and she
thirty-three; they had two children, a son and a daughter. Amelia died in 1854,
and “the shocktook a long time to wear off,” writes Joule’s most recent biographer,
Donald Cardwell. “His friends and contemporaries agreed that this never
very assertive man became more withdrawn.” About fourteen years later, Joule
fell in love again, this time with his cousin Frances Tappenden, known as
“Fanny.” In a letter to Thomson he writes “an affection has sprung up between
me and my cousin you saw when last here. There are hindrances in the way so
that nothing may come of it.” The “hindrances” prevented marriage, and eventually
Fanny married another man.
Joule’s political leanings were conservative. He had a passionate, sometimes
irrational, dislike of reform-minded Liberal politicians such as William Gladstone and John Bright. In a letter to John Tyndall, he wrote, “The fact is that Mr. Gladstone
was fashioning a neat machine of ‘representation’ with the object of keeping
himself in power. . . . Posterity will judge him as the worst ‘statesman’ that England
ever had and the verdict with regard to that Parliament will be ditto, ditto.”
Joule had a personality that was “finely poised,” as another biographer, J. G.
Crowther, puts it. On the one hand he was conducting experiments with unlimited
care and patience, and on the other hand fulminating against Liberal politicians.
He feared that too much mental effort would threaten his health. In 1860,
a new professorship of physics was created at Owens College in Manchester, and
Joule could have had it, but he decided not to apply, as he explained in a letter
to Thomson: “I have not the courage to apply for the Owens professorship. The
fact is that I do not feel it would do for me to overtaskmy brain. A few years
ago, I felt a very small mental effort too much for me, and in consequence spared
myself from thought as much as possible. I have felt a gradual improvement, but
I do not thinkit would be well for me to build too much on it. I shall do a great
deal more in the long run by taking things easily.”
Joule’s life was hectic and burdensome at this time, and he may have felt that
he was near breakdown. Amelia died in 1854, the brewery was sold in the same
year, and the experiments with Thomson were in progress. During the next six
years, he moved his household and laboratory twice. After the second move, he
was upset by an acrimonious dispute with a neighbor who objected to the noise
and smoke made by a three-horsepower steam engine Joule included in his apparatus.
The neighbor was “a Mr Bowker, an Alderman of Manchester and chairman
of the nuisances committee, a very important man in his own estimation
like most people who have risen from the dregs of society.”
During this same period, Joule narrowly escaped serious injury in a train
wreck, and after that he had an almost uncontrollable fear of railway travel. At
the same time, he loved to travel by sea, even when it was dangerous. In a letter
to Fanny, he described a ten-mile trip to Tory Island, in the Atlantic off the coast
of Ireland, where his brother owned property: “Waves of 4 to 600 feet from crest
to crest and 20 feet high. Dr Brady who was with us and had yachted in the
ocean for 25 years said he was never in a more dangerous sea. However the
magnificence of it tookaway the disagreeable sense of danger which might have
prevailed.”
In some measures of scientific ability, Joule was unimpressive. As a theorist,
he was competent but not outstanding. He was not an eloquent speaker, and he
was not particularly important in the scientific establishment of his time. But
Joule had three things in extraordinary measure—experimental skill, independence,
and inspiration.
He was the first to understand that unambiguous equivalence principles could
be obtained only with the most inspired attention to experimental accuracy. He
accomplished his aim by carefully selecting the measurements that would make
his case. Crowther marvels at the directness and simplicity of Joule’s experimental
strategies: “He did not separate a quantity of truth from a large number of
groping unsuccessful experiments. Nearly all of his experiments seem to have
been perfectly conceived and executed, and the first draft of them could be sent
almost without revision to the journals for publication.”
For most of his life, Joule had an ample independent income. That made it
possible for him to pursue a scientific career privately, and to build the kind of intellectual independence he needed. Crowther tells us about this facet of Joule’s
background:
As a rich young man he needed no conventional training to qualify him for a
career, or introduce him to powerful future friends. His early researches were
pursued partly in the spirit of a young gentleman’s entertainment, which happened
to be science instead of fighting or politics or gambling. It is difficult to
believe that any student who had received a lengthy academic training could
have described researches in Joule’s tone of intellectual equality. The gifted
student who has studied under a great teacher would almost certainly adopt a
less independent tone in his first papers, because he would have the attitude
of a pupil to his senior, besides a deference due to appreciation of his senior’s
achievements. A student without deference after distinguished tuition is almost
always mediocre.
Joule was not entirely without distinguished tuition. Beginning in 1834, and
continuing for three years, Joule and his brother Benjamin studied with John
Dalton, then sixty-eight and, as always, earning money teaching children the
rudiments of science and mathematics. The Joules’ studies with Dalton were not
particularly successful pedagogically. Dalton tookthem through arithmetic and
geometry (Euclid) and then proceeded to higher mathematics, with little attention
to physics and chemistry. Dalton’s syllabus did not suit Joule, but he benefited
in more-informal ways. Joule wrote later in his autobiographical note, “Dalton
possessed a rare power of engaging the affection of his pupils for scientific truth;
and it was from his instruction that I first formed a desire to increase my knowledge
by original researches.” In his writings, if not in his tutoring, Dalton emphasized
the ultimate importance of accurate measurements in building the
foundations of physical science, a lesson that Joule learned and used above all
others. The example of Dalton, internationally famous for his theories of chemical
action, yet self-taught, and living and practicing in Manchester, must have convinced
Joule that he, too, had prospects.
Joule’s independence and confidence in his background and talents, natural
or learned from Dalton, were tested many times in later years, but never shaken.
His first determination, in 1843, of the mechanical equivalent of heat was ignored,
and subsequent determinations were given little attention until Thomson
and Stokes took notice at the British Association meeting in 1847.
When Joule submitted a summary of his friction experiments for publication,
he closed the paper with three conclusions that asserted the heat-mechanicalworkequivalence
in the friction experiments, quoted his measured value of J,
and stated that “the friction consisted in the conversion of mechanical power to
heat.” The referee who reported on the paper (believed to have been Faraday)
requested that the third conclusion be suppressed.
Joule’s first electrochemistry paper was rejected for publication by the Royal
Society, except as an abstract. Arthur Schuster reported that, when he asked Joule
what his reaction was when this important paper was rejected, Joule’s reply was
characteristic: “I was not surprised. I could imagine those gentlemen sitting
around a table in London and saying to each other: ‘What good can come out of
a town [Manchester] where they dine in the middle of the day?’ ”
But with all his talents, material advantages, and intellectual independence, Joule could never have accomplished what he did if he had not been guided in
his scientific workby inspiration of an unusual kind. For Joule “the study of
nature and her laws” was “essentially a holy undertaking.” He could summon
the monumental patience required to assess minute errors in a prolonged series
of measurements, and at the same time transcend the details and see his work
as a quest “for acquaintance with natural laws . . . no less than an acquaintance
with the mind of God therein expressed.” Great theorists have sometimes had
thoughts of this kind—one might get the same meaning from Albert Einstein’s
remarkthat “the eternal mystery of the world is its comprehensibility”—but experimentalists,
whose lives are taken up with the apparently mundane tasks of
reading instruments and designing apparatuses, have rarely felt that they were
communicating with the “mind of God.”
It would be difficult to find a scientific legacy as simple as Joule’s, and at the
same time as profoundly important in the history of science. One can summarize
Joule’s major achievement with the single statement
J 778 ft-lb per Btu,
and add that this result was obtained with extraordinary accuracy and precision.
This is Joule’s monument in the scientific literature, now quoted as 4.1840
kilogram-meters per calorie, used routinely and unappreciatively by modern students
to make the quantitative passage from one energy unit to another.
In the 1840s, Joule’s measurements were far more fascinating, or disturbing,
depending on the point of view. The energy concept had not yet been developed
(and would not be for another five or ten years), and Joule’s number had not
found its niche as the hallmarkof energy conversion and conservation. Yet Joule’s
research made it clear that something was converted and conserved, and provided
vital clues about what the something was.