"The Artifice of Sadi Carnot: Reflections on his 230th anniversary", by Alejandro Jenkins

00:00:00 Introduction 00:02:29 Mechanics of engines 00:31:33 Sadi Carnot (1796-1832), Capitaine du Génie 00:54:12 Carnot's artifice 01:34:24 Active forces 02:00:58 Outlook Speaker: Alejandro Jenkins, University of Costa Rica Summary: Sadi Carnot is one of the most unusual and enigmatic figures in the history of physics. Son of "the Great Carnot, Organizer of the Victory", uncle of a future President of the French Republic, graduate of the prestigious École Polytechnique of Paris (which his father had helped establish), Carnot enjoyed little success in his career as a military engineer and published a single scientific work that went almost unnoticed before his death in an insane asylum at age 36. Nonetheless, today Sadi Carnot is considered the founder of thermodynamics and, in Feynman's words, one of the few instances of an engineer who made a fundamental contribution to theoretical physics. In this talk I wish not only to say something about what little we know of Carnot’s life, but also to explain the reasoning that allowed him to establish thermodynamics while still almost wholly ignorant of the nature of heat. I revisit some of his most notable arguments, including one of which Kelvin would later write that "nothing in the whole range of Natural Philosophy is more remarkable than the establishment of general laws by such a process of reasoning." I contrast Carnot’s profound curiosity about the operation of useful engines with the disdain of Euler, who left to posterity an analytical mechanics that cannot account for the simplest motor. I shall conclude with some personal reflections on how Carnot’s legacy might help orient us towards a more realistic theory of engines that might dissipate the obscurities and fictions that continue to beset the theory of non-equilibrium thermodynamics.