It is difficult to place nationally the Benjamin Thompson who was born (1753) and reared in America, knighted in England, and made Count Rumford in Bavaria, and who died in France (1814). In the War of American Independence he sided with Britain, and moved to London (1776). Sent back to serve as British secretary in the colony of Georgia, his interest overflowed from politics to science, and he made researches which won him a fellowship in the Royal Society. In 1784, with the permission of the British government, he entered the service of Bavaria under Prince Maximilian Joseph. In the next eleven years, as Bavarian minister of war and police, he reorganized the Army, improved the condition of the working class, ended mendicancy, and found time to contribute papers for the Philosophical Transactions of the Royal Society. The grateful Maximilian made him (1791) a count of the Holy Roman Empire; he took for his title the name of his wife’s birthplace (now Concord) in Massachusetts. During a year in Britain (1795) he labored to better the heating and cooking arrangements of the people, with a view to reducing domestic pollution of the air. After another year of service in Bavaria, he returned to England, and, with Sir Joseph Banks, established the Royal Institution. He founded—and was the first to receive—the Rumford Medal of the Royal Society. He provided funds for the award of a similar medal by academies of arts and sciences in Bavaria and America, and for the Rumford professorship in Harvard University. After the death of his wife he moved to Paris (1802), took a house in Auteuil, married the widow of Lavoisier, and remained in France despite the renewal of war with England. Active to the end, he labored, in his final year, to feed with “Rumford soup” the French populace nearing destitution as Napoleon, taking all available sons, marched to his doom.

Rumford’s contributions to science were too varied and incidental to be spectacular, but, taken altogether, they formed a remarkable counterpoint to a busy administrative life. While watching the boring of cannon in Munich he was struck by the heat which the operation produced. To measure this he arranged to have a solid metal cylinder rotate with its head against a steel borer, all in a watertight box containing eighteen and three-quarter pounds of water. In two and three-quarter hours the temperature of the water rose from 60 degrees Fahrenheit to 212 degrees—the boiling point. “It would be difficult,” Rumford later recalled, “to describe the astonishment expressed in the countenances of the bystanders on seeing so large a quantity of water heated, and actually made to boil, without any fire.”1 This experiment proved that heat was not a substance but a mode of molecular motion roughly proportioned in degree to the amount of work done to produce it. This belief had been held long before, but Rumford’s device provided its first experimental proof, and a method of measuring the mechanical equivalent of heat—i.e., the amount of work required to heat one pound of water one degree.

Thomas Young was almost as “undulant and diverse” as Rumford and Montaigne. Born (1773) of Quaker parentage in Somerset, he began with religion, and then passed, with undiminished devotion, to science. At the age of four, we are assured, he had read the Bible through twice, and at fourteen he could write in fourteen languages.2 At twenty-one he was elected a fellow of the Royal Society; at twenty-six he was an established physician in London; at twenty-eight he was teaching physics in the Royal Institution; and in 1801 he began there the experiments that confirmed and developed Huyghens’ conception of light as undulations of a hypothetical ether. After much debate this view generally—not universally—displaced Newton’s theory of light as the emanation of material corpuscles. Young also offered the hypothesis, later developed by Helmholtz, that the perception of color depends upon the presence in the retina of three kinds of nerve fibers, respectively responsive to red, violet, and green. For good measure he gave the first descriptions of astigmatism, blood pressure, capillary attraction, and tides, and shared actively (1814) in the decipherment of the Rosetta Stone. He was, said a learned historian of medicine, “the most highly educated physician of his time,” and, added Helmholtz, “one of the most clear-sighted men who ever lived.”3

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