Carnot, Nicolas Léonard Sadi
Nicolas Léonard Sadi Carnot (1796-1832), French physicist who developed the theory behind heat engines. Carnot’s Réflexions sur la Puissance Motrice du Feu (Reflections on the Motive Power of Fire, 1824) laid out principles that would influence the most fundamental laws of science and engineering: the Law of Conservation of Energy and the First and Second Laws of Thermodynamics. In Réflexions, Carnot sought to answer two fundamental questions: first, whether there was an upper limit to the power of heat; and second, whether there was a better means than steam to produce this power. He proposed that work was generated by the passage of caloric from a warmer to a cooler body, with caloric being conserved in the process. Rudolf Clausius later showed, however, that heat was in fact not conserved; yet this did not undermine the validity or importance of Carnot’s results. Carnot deduced that the efficiency of the engine depended only on the temperature at the heat source and at the heat sink, and not on the temperature of the working substance. The first deduction is known as the Carnot Cycle, the second as Carnot's Theorem.
Further Reading
Nicolas Léonard Sadi Carnot - Biography (ThinkQuest: Library)
Main discoveries of Sadi Carnot that led to the foundation of thermodynamics (The Carnot Foundation)
