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RUMFORD, Count (Benjamin Thompson). "On the Propagation of Heat in Various Substances" and "An Inquiry concerning the Source of the Heat Excited by Friction" in Count Rumford's Experimental Essays. Political, Economical and Philosophical (volume II), Essay VIII and Essay IX. London, T. Cadell and W. Davies, 1798. (ii), (ii), pp 398-496, with two folding plates. Essay VIII on 398-465, one folding plate; Essay IX pp469-496, one folding plate. Original wrappers recently and beautifully restored and rebacked; additionally, the spine has been expertly and painstakingly restored. The pamphlet is housed in a new solander case, with a calf spine (imprinted Rumford s Cannon-Boring Experiment of 1798 ) and marbled boards. This is a lovely effort in restoration and binding. [++] Rumford (born in Woburn, Massachusetts as Benjamin Thompson) was a soldier of fortune and scientist who would become chief minister of the Bavarian army, and who fundamentally changed the ideas of caloric and heat. "It was during his investigations of cannon [and gunpowder, 1796-8] that [Thompson] was impressed by the large amount of heat generated in cannon barrels by the explosion of gunpowder even when no ball was being fired. He was thus led to accept the vibratory theory of heat, which he championed actively all his life. Thompson s most famous experiment in this area was his demonstration of the process of boring cannon with a dull drill [described and reported in the papers offered here], which he carried out in the arsenal at Munich. [Rumford took an unfinished cannon and modified this section to allow it to be enclosed by a watertight box while a blunted boring tool was used on it.] Because the heat generated in this process seemed limit-less, he reasoned that a fluid caloric did not exist. Thompson carried out many other experiments to demonstrate the reasons for his disbelief in the caloric theory. He unsuccessfully attempted to determine whether heat had weight, which would be an attribute of a fluid; he weighted, at different temperatures, fluids that had markedly different specific heats and heats of fusion. He studied the anomalous expansion of fusion. He studied the anomalous expansion of water between 4°C and 0°C to show that the concept that thermal expansion is caused by fluid caloric taking up space was false. He never realized the connection between heat and energy, although he did carry on experiments to demonstrate spontaneous interdiffusion of different density liquids at constant temperature, and he postulated that fluids are in constant random motion."--Complete DSB online (Rumford) [++] "The cannon work was one of the Count s many efforts to understand heat and discredit the then solidly entrenched belief that heat was an element, caloric. [J.P.] Joule lauded Rumford s work and mined his data decades later for comparison with his own on the mechanical equivalent of heat."--Frederic E. Schubert, "Rumford s Experimental Challenge to Caloric Theory: Big Science 18th-Century." Journal of Chemical Education 2019 96 (9), 1955-1960 [++] "In one spectacular experiment [described in the papers offered] Rumford had the barrel of the cannon bored under water, using horses to move the cannon round. To the amazement of the spectators, the water was made to boil, and continued to do so as long as the machining of the metal carried on. The main conclusion reached by Rumford was that heat could not in fact be a material substance, as supposed in the caloric theory, but was the result of the mechanical energy consumed during the boring operation. The idea, held even by such eminent scientists as Lavoisier, that heat might be a chemical element could no longer be accepted."--David Darling (Science Writer) online. N° de réf. du vendeur ABE-1700328642601
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