History of Science and Engineering Annotation << Back ANALOGIES IN THE CREATION OF THE PHENOMENOLOGICAL IDEAL HEAT MACHINE THEORY A.F. Smyk, N.B. Kuzmina The article deals with the genesis of the ideal heat engine theory, first proposed by S. Carnot in 1824. He “designed” an ideal heat engine, consisting of two heat sources with different temperatures and a working substance with elastic properties, drawing conclusions by analogy. Based on the concept of heat as a weightless substance - caloric, Carnot used the analogy between the transfer of caloric from a more heated source to a less heated one and the fall of water in a mechanical hydraulic machine. The article also reviewed analogy between the transfer of caloric matter and the potential difference in a Volta battery. These analogies allowed Sadi Carnot to examine in detail the cyclical transformation of heat into work and establish that the efficiency of a heat engine is determined only by the temperature difference between the heater and the cooler. Keywords: Sadi Carnot; principles of thermodynamics; ideal heat engine; cycle method; analogy method. DOI: 10.25791/intstg.06.2019.696 Contacts: E-mail: afsmyk@mail.ru Pp. 03-09.