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The Remarkable American Count
Brilliant Benjamin Thompson won world fame as Count Rumford the scientist but never dispelled his countrymen’s suspicions
December 1956 | Volume 8, Issue 1
Count Rumford’s fame in Bavaria rested in large part upon his social reforms, and by these achievements he was known as well to the rest of Europe, but his permanent reputation depends much more upon his scientific work, much of which he carried through while serving the Elector. The most important of the more than seventy scientific papers he wrote dealt with heat and most of them with the problem of “caloric.” In his day, there was a distinct division among scientific men between those who considered heat a form of energy-a mode of motion-and those who believed that heat was caused by the addition of a fluid called “caloric.” Rumford became the great protagonist of the energy theory of heat. He devised a series of experiments which disposed of one after another of the arguments of the caloricists.
Most famous of all was his cannon-boring experiment, in which he demonstrated the heat produced by the friction which is involved in boring out a solid casting for a six-pounder cannon. The casting was insulated by being immersed in water which was quickly raised to the boiling point. The energy theory was not fully accepted for another sixty years, but Rumford’s conclusion was irrefutable: “anything which any insulated body, or system of bodies, can continue to furnish without limitation, cannot possibly be a material substance.” He saw no alternative, “except it be motion.”
The Count went on to obtain a figure for the mechanical equivalent of heat, that is, the amount of mechanical work required to raise a given quantity of water a single degree. He plagued the caloricists by showing that water expanded when cooled below 4° centigrade as well as when it was heated above that temperature, by demonstrating that heat could travel through a vacuum, and by revealing that a converging lens was heated as much as a diverging lens. Rumford, too, was the first to describe convection currents.
In 1795 Count Rumford journeyed to London to supervise the publication of his Essays, Political, Economical, and Historical, which did much to make his reputation in the world of science. While there, he enjoyed again English intellectual society, accepted membership in the Royal Irish Academy, and summoned from the other side of the Atlantic his now-grown daughter, whom he had not seen since she was the tiniest infant.
His stay in London was brought to a sudden end by the arrival of a courier with a frantic message from the Elector imploring his immediate return to Munich. Bavaria’s precarious neutrality was threatened by armies of the hostile states of Austria and France, both of which were driving toward the capital. The Elector informed Rumford that he had appointed him president of a council of regency with plenary powers and that the fate of Bavaria depended upon him. Charles Theodore then fled to Saxony while the Count closed the gates of the city, mobilized all the forces he could, and prevailed upon both the French and the Austrians to abandon their intention of entering Munich. Thus, quite probably, he prevented serious damage to the capital and won the renewed gratitude of the Bavarians and their sovereign.
Yet despite his efficiency and effectiveness, he had raised as many bitter enemies in Bavaria as he did everywhere else. By 1798 the rising opposition had become so great that the Elector accepted the prudent course and permitted Rumford to retire to England. He sought, however, to retain Rumford’s services by appointing him Bavarian minister to that nation. This England refused, ostensibly because he was a British subject, but also because of objections to the man based upon his past.
At the zenith of his career, he thought much about America during the busy years in England that followed. As early as 1793, he had inquired of his only American friend, Loammi Baldwin, whether he would be permitted to visit his native land. With this question still unsettled, he next donated approximately equal funds to Boston’s American Academy of Arts and Sciences and to the Royal Society, to found the Rumford Medals for research in heat or light. In 1799 he made known to the American minister in London his interest in being appointed superintendent of the United States Military Academy. With the plans for the academy then being formulated, this project was looked upon favorably by the unknowing until, once again, his past record was called up to frustrate any such appointment.
Much of Rumford’s energy was diverted into the founding of the Royal Institution, whose imposing building stands at the top of Albemarle Street in London. The honorable purpose was to establish helpful and practical relations between scientists and working men. But this founder was a choleric, contentious sort; by 1802 he had a falling out with the trustees of the institution, including Humphrey Davy, whom he himself had chosen. Shortly thereafter he left England in haughty anger, never to return.