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Monday, September 17, 2007

Reading List: Degrees Kelvin

Lindley, David. Degrees Kelvin. Washington: Joseph Henry Press, 2004. ISBN 0-309-09618-9.
When 17 year old William Thomson arrived at Cambridge University to study mathematics, Britain had become a backwater of research in science and mathematics—despite the technologically-driven industrial revolution being in full force, little had been done to build upon the towering legacy of Newton, and cutting edge work had shifted to the Continent, principally France and Germany. Before beginning his studies at Cambridge, Thomson had already published three research papers in the Cambridge Mathematical Journal, one of which introduced Fourier's mathematical theory of heat to English speaking readers, defending it against criticism from those opposed to the highly analytical French style of science which Thomson found congenial to his way of thinking.

Thus began a career which, by the end of the 19th century, made Thomson widely regarded as the preeminent scientist in the world: a genuine scientific celebrity. Over his long career Thomson fused the mathematical rigour of the Continental style of research with the empirical British attitude and made fundamental progress in the kinetic theory of heat, translated Michael Faraday's intuitive view of electricity and magnetism into a mathematical framework which set the stage for Maxwell's formal unification of the two in electromagnetic field theory, and calculated the age of the Earth based upon heat flow from the interior. The latter calculation, in which he estimated only 20 to 40 million years, proved to be wrong, but was so because he had no way to know about radioactive decay as the source of Earth's internal heat: he was explicit in stating that his result assumed no then-unknown source of heat or, as we'd now say, “no new physics”. Such was his prestige that few biologists and geologists whose own investigations argued for a far more ancient Earth stepped up and said, “Fine—so start looking for the new physics!” With Peter Tait, he wrote the Treatise on Natural Philosophy, the first unified exposition of what we would now call classical physics.

Thomson believed that science had to be founded in observations of phenomena, then systematised into formal mathematics and tested by predictions and experiments. To him, understanding the mechanism, ideally based upon a mechanical model, was the ultimate goal. Although acknowledging that Maxwell's equations correctly predicted electromagnetic phenomena, he considered them incomplete because they didn't explain how or why electricity and magnetism behaved that way. Heaven knows what he would have thought of quantum mechanics (which was elaborated after his death in 1907).

He'd probably have been a big fan of string theory, though. Never afraid to add complexity to his mechanical models, he spent two decades searching for a set of 21 parameters which would describe the mechanical properties of the luminiferous ether—what string “landscape” believers might call the moduli and fluxes of the vacuum, and argued for a “vortex atom” model in which extended vortex loops replaced pointlike billiard ball atoms to explain spectrographic results. These speculations proved, as they say, not even wrong.

Thomson was not an ivory tower theorist. He viewed the occupation of the natural philosopher (he disliked the word “physicist”) as that of a problem solver, with the domain of problems encompassing the practical as well as fundamental theory. He was a central figure in the development of the first transatlantic telegraphic cable and invented the mirror galvanometer which made telegraphy over such long distances possible. He was instrumental in defining the units of electricity we still use today. He invented a mechanical analogue computer for computation of tide tables, and a compass compensated for the magnetic distortion of iron and steel warships which became the standard for the Royal Navy. These inventions made him wealthy, and he indulged his love of the sea by buying a 126 ton schooner and inviting his friends and colleagues on voyages.

In 1892, he was elevated to a peerage by Queen Victoria, made Baron Kelvin of Largs, the first scientist ever so honoured. (Numerous scientists, including Newton and Thomson himself in 1866 had been knighted, but the award of a peerage is an honour of an entirely different order.) When he died in 1907 at age 83, he was buried in Westminster Abbey next to the grave of Isaac Newton. For one who accomplished so much, and was so celebrated in his lifetime, Lord Kelvin is largely forgotten today, remembered mostly for the absolute temperature scale named in his honour and, perhaps, for the Kelvinator company of Detroit, Michigan which used his still-celebrated name to promote their ice-boxes and refrigerators. While Thomson had his hand in much of the creation of the edifice of classical physics in the 19th century, there isn't a single enduring piece of work you can point to which is entirely his. This isn't indicative of any shortcoming on his part, but rather of the maturation of science from rare leaps of insight by isolated geniuses to a collective endeavour by an international community reading each other's papers and building a theory by the collaborative effort of many minds. Science was growing up, and Kelvin's reputation has suffered, perhaps, not due to any shortcomings in his contributions, but because they were so broad, as opposed to being identified with a single discovery which was entirely his own.

This is a delightful biography of a figure whose contributions to our knowledge of the world we live in are little remembered. Lord Kelvin never wavered from his belief that science consisted in collecting the data, developing a model and theory to explain what was observed, and following the implications of that theory to their logical conclusions. In doing so, he was often presciently right and occasionally spectacularly wrong, but he was always true to science as he saw it, which is how most scientists see their profession today.

Amusingly, the chapter titles are:

  1. Cambridge
  2. Conundrums
  3. Cable
  4. Controversies
  5. Compass
  6. Kelvin

Posted at September 17, 2007 23:01