Réflexions sur la puissance motrice du feu et sur les machines propres a developper cette puissance
1824
Nicolas Leonard Sadi Carnot(1796-1832)
 Carnot first investigated and theorized the thermal efficiency of the steam engine. Employing the caloric-theory, he compared the motive power of heat to that of falling water. From this Carnot concluded that the power of heat is generated by differences in temperature and quantity of calorics in the same way that the power of falling water depends on the head and quantity of water. He first demonstrated the equivalency and interchangeability between heat and mechanistic work, and thus initiated a new realm of physics that came to be known as thermodynamics.