Nicolas Léonard Sadi Carnot

Nicolas Léonard Sadi Carnot (French: [nikɔla leɔnaʁ sadi kaʁno]; 1 June 1796 – 24 August 1832) was a <a href="/facts/French_people/984axQ8y">French</a> <a href="/facts/Military_engineering/dzAR2FJI">military engineer</a> and <a href="/facts/Physicist/cQcgvSIm">physicist</a>. A graduate of the <a href="/facts/%25C3%2589cole_polytechnique/0DS7aMaR">École polytechnique</a>, Carnot served as an officer in the <a href="/facts/Engineering_Arm/toKexev9">Engineering Arm</a> (le génie) of the <a href="/facts/French_Army/NCnjovlu">French Army</a>. He also pursued scientific studies and in June 1824 published an essay titled <a href="/facts/Reflections_on_the_Motive_Power_of_Fire/KmBj7Xq8">Reflections on the Motive Power of Fire</a>. In that book, which would be his only publication, Carnot developed the first successful theory of the <a href="/facts/Thermal_efficiency/fR0ysNpr">maximum efficiency</a> of <a href="/facts/Heat_engine/t1gq4r5d">heat engines</a>.
Carnot's scientific work attracted little attention during his lifetime, but in 1834 it became the object of a detailed commentary and explanation by another French engineer, <a href="/facts/%25C3%2589mile_Clapeyron/108oIBhT">Émile Clapeyron</a>. Clapeyron's commentary in turn attracted the attention of <a href="/facts/William_Thomson%2c_1st_Baron_Kelvin/LTIxG1jV">William Thomson</a> (later Lord Kelvin) and <a href="/facts/Rudolf_Clausius/RMgFgY7I">Rudolf Clausius</a>. Thomson used Carnot's analysis to develop an absolute <a href="/facts/Thermodynamic_temperature/JXeJJPa6">thermodynamic temperature</a> scale, while Clausius used it to define the concept of <a href="/facts/Entropy/s52IXeFz">entropy</a>, thus formalizing the <a href="/facts/Second_law_of_thermodynamics/m7SJ2eeH">second law of thermodynamics</a>.
Sadi Carnot was the son of <a href="/facts/Lazare_Carnot/t9cV2MU9">Lazare Carnot</a>, an eminent mathematician, engineer, and commander of the <a href="/facts/French_Revolutionary_Army/5S7JENdQ">French Revolutionary Army</a> and later of the <a href="/facts/Grande_Arm%25C3%25A9e/5aqjSLYa">Napoleonic army</a>. Some of the difficulties that Sadi faced in his own career might have been connected to the persecution of his family by the <a href="/facts/Bourbon_Restoration_in_France/hKbV35eL">restored Bourbon monarchy</a> after the fall of Napoleon in 1815. Sadi Carnot died in relative obscurity at the age of 36, but today he is often characterized as the "father of <a href="/facts/Thermodynamics/q4hIx3yP">thermodynamics</a>".

Nicolas Léonard Sadi Carnot open-in-new

Nicolas Léonard Sadi Carnot