Carnot's 1824 treatise on thermodynamics. Title page of 'Reflexions sur la puissance motrice du feu' (Reflections on the Motive Power of Fire, 1824) by French physicist Sadi Carnot (1796-1832). This work contained his theories on heat engines and the Carnot cycle, laying the foundations of the second law of thermodynamics. The work also covered concepts such as the Carnot efficiency and the Carnot theorem. This work was published in Paris, France.