Prof. Raffaele Pisano
Université de Lille
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1824-2024: Reading Sadi Carnot, Thermodynamics’ Genesis & its Heritage
In 1824, Sadi Carnot (1796-1832) presented the basics of thermodynamics (2nd principle only) in his only published book–Réflexions sur la puissance motrice du feu (hereafter Réflexions). Sadi Carnot knew Watt’s works. In his Réflexions he dealt with heat machines and gas theory through: a) the caloric hypothesis mixed with a weak heat concept, b) the 4-phases cycle and c) ad absurdum proof theorem (atypical for a physical science at that time). The impossibility of perpetual motion was linked to state of a system, reversible processes and cycle (four phases). In his unpublished Notes sur les mathématiques, la physique et autres sujets (s.d.) he made slight and indirect use of the hypothesis on puissance motrice conservation/heat–work (Cfr. Carnot s.d., pp. 134–135). He also provided a cycle (three phases) in his unpublished Recherche d’une formule propre à représenter la puissance motrice de la vapeur d’eau (between November 1819 and March 1827). At the beginning of the discursive part of Réflexions – and at the end of his celebrated theorem – he claimed that work can be obtained every time there is a difference in temperature between which heat flows (Cfr. Pisano’s works). He proposed a different manner to close his own cycle (displayed by cylinders only) and determined (erroneously) the mathematical function of the efficiency for an heat machine. In my talk I present an historical–scientific genesis of Sadi Carnot’s thermodynamics in his Réflexions (1824) and a reading of its early heritage (1834-1870).
Selected References
Carnot L ([1783] 1786) Essai sur les machines en général. Defay, Dijon.
Carnot L (1778) Mémoire sur la théorie des machines pour concourir au prix de 1779 propose par l’Académie Royale des Sciences de Paris. The manuscript is conserved in the Archives de l’Academie des sciences, Institut de France, and consists of 85 sections in 63 folios. Sections 27–60 are reproduced. In: Gillispie (1971), Appendix B, pp. 271–296 | See also: Carnot L (1780) Mémoire sur la théorie des machines pour concourir au prix que l’Académie Royale des Sciences de Paris doit adjuger en 1781. The manuscript is dated from Béthune 15 July 1780. It is conserved in the Archives de l’Académie des sciences, Institut de France, and consists of 191 sections in 106 folios. Sections 101–160 are reproduced. In: Gillispie (1971), Appendix C, pp. 299–343.
Carnot S (1878) Réflexions sur la puissance motrice du feu sur les machinés propre à développer cette puissance. Gauthier–Villars, Paris.
Clapeyron EBP (1834) Mémoire sur la puissance motrice du feu. Journal de l’École Royal Polytechnique XXIII/XIV:153–190. [Collections École polytechnique Z 5 (1834)].
Gillispie CC, Pisano R (2014) Lazare and Sadi Carnot. A Scientific and Filial Relationship. 2nd edition. Springer, Dordrecht [On St Robert, see Chap. X].
Pisano R, Cooppersmith J, Australia, Peake M (2021) Essay on Machines in General (1786). Text, Translations and Commentaries. Lazare Carnot’s Mechanics – Vol. 1. Springer, Cham.
