The Abyss of Time - Four Revolutions in the Earth Sciences - page 2

The Abyss of Time
Gone Right Through It
In September 1846, the faculty of the University of Glasgow convened to examine
an applicant for its chair in natural philosophy, the previous holder, appointed in
1803, having passed on after a lengthy illness. At age twenty-two, the candidate,
William Thomson (1824-1907), was easily mistaken for a student himself. In spite
of his youth, the Cambridge graduate had already accomplished more than enough
to justify his candidacy, but there was one additional hurdle. Before an appoint-
ment could become official, the applicant had to write and deliver, in Latin, an es-
sayassignedbythefaculty.Thomson'stopicwastobe De caloris distributione per
terrae corpus : “The distribution of heat within the Earth.” The title echoed that of
Joseph Fourier's famous topic on heat flow. Either Thomson himself or his father,
James, a long-time member of the Glasgow faculty and his son's strongest booster,
had proposed the topic. 1 Both knew that no one was better qualified to address the
question of the Earth's heat than William, who at age sixteen had already mastered
Fourier's difficult mathematics.
William Thomson had learned of Fourier's The Analytical Theory of Heat in
1839 from the lectures of Professor John Nichol, who told the teenager that “per-
haps” he could understand this work of “transcendent merit.” According to Wil-
liam's later recollection, “I took Fourier out of the University Library; and in a
fortnight I had mastered it—gone right through it.” 2 The following summer James
Thomson took his children on a trip to Germany. Before leaving, William had
picked up a topic by Phillip Kelland, professor of mathematics at Edinburgh, titled
Theory of Heat . Fourier, Kelland alleged, had made an error. Indignant at this
slander of his hero and already a budding academic, William penned an article
titled “On Fourier's Expansions of Functions in Trigonometrical Series” and sub-
mitted it to the Cambridge Mathematical Journal , which published it. 3 The au-
thor was listed not as William Thomson but, at the suggestion of his father, as the
pseudonymous P. Q. R. James Thomson evidently thought it inappropriate for his
sixteen-year-old son to rebuke in print a distinguished colleague. 4
As further evidence that young Thomson's essay topic had not been chosen at
random, in 1842, at age eighteen, the precocious youngster had published a mem-
oir titled “On the Linear Motion of Heat.” 5 Using Fourier's approach, he solved