Sadi Carnot and the Thermodynamics of James Watt

Abstract

A comparison of Carnot’s thermodynamic statements, published in his Reflections, with the Watt’s thermodynamic ideas shows that Carnot used Watt’s thermodynamics, but he did not understand it properly. For instance, he did not realize the Watt’s idea that production of work in the steam engine requires a consumption of heat. Also, instead of the pressure difference boi ler-to-condenser, Carnot used the temperature difference to be the direct quantity for the transport of caloric in the engine. Many of Carnot’s state ments are shown to express Watt’s ideas in other wording. Watt realized the reversible heat transfer in experiment several decades prior to Reflections. In addition, Carnot’s analogy of steam engine and water fall, published 1824, has been invalidated, long before its birth, by the Watt’s formulation of the first law in 1774. Despite these facts, James Watt is banished from the history of thermodynamics.