Published online by Cambridge University Press: 05 January 2009
In 1813, two young physicists, François Delaroche and Jacques-Étienne Bérard, published a series of highly influential measurements of the specific heats of a number of common gases. Their results, obtained in answer to a prize competition set by the Institut de France, were accepted as the most accurate then available and they continued to exert a powerful, if diminishing, influence on studies of heat for the next forty years. Among the results obtained by Delaroche and Bérard were two measurements which showed that the specific heat of air decreased when the pressure was raised. This was a new and important experimental result. The ‘effect’ was found to be spurious of course (definitively by Victor Regnault as late as 1862), but in the meantime it was clear endorsement of some of the tenets of the caloric theory of heat. It could be invoked, for example, to explain the rise of temperature of a gas when it was compressed adiabatically. Robert Fox in his study of the rise and fall of the caloric theory has written:
Their error, although less than 10 per cent, was to prove one of the most influential in the whole history of the study of heat. Backed by the prestige associated with victory in the Institute's competition, the result quickly became standard and… was to mislead many calorists.
1 Delaroche, F. and Bérard, J.-E., ‘Sur la détermination de la chaleur spécifique des differens gaz’, Annales de chimie et de physique, (1813), 85, pp. 72–110, 113–182.Google Scholar For some reason there are two different printings of this volume of the Annales, distinguished by typeface and some spellings. The one which is evidently later has several more numerical misprints than the other.
2 Fox, Robert, ‘The Caloric Theory of Gases from Lavoisier to Regnault’, Oxford, 1971, pp. 134–150Google Scholar gives an account of the circumstances surrounding these experiments.
3 Ibid., p. 140.
4 Delaroche, and Bérard, , op. cit. (1), pp. 104, 108.Google Scholar
5 Ibid., p. 109 and p. 176, note 1.
6 Compare ibid., p. 102 and footnote with p. 107 and footnote.
7 Ibid., p. 90.
8 Ibid., p. 126.
9 Ibid., p. 128.
10 Ibid., p. 138.
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