A Tale of Two Revolutions
The story of thermodynamics begins in 1824 in Paris. France had been rocked to its foundations by thirty-five years of war, revolution, and dictatorship. A king had been executed, constitutions had been written, Napoleon had come and gone twice, and the monarchy had been restored twice. Napoleon had successfully marched his armies through the countries of Europe and then disastrously into Russia. France had been invaded and occupied and had paid a large war indemnity.
In 1824, a technical memoir was published by a young military engineer who had been born into this world of social, military, and political turmoil. The engineer's name was Sadi Carnot, and his book had the title Reflections on the Motive Power of Fire. By “motive power” he meant work, or the rate of doing work, and “fire” was his term for heat. His goal was to solve a problem that had hardly even been imagined by his predecessors. He hoped to discover the general operating principles of steam engines and other heat engine devices that supply work output from heat input. He did not quite realize his purpose, and his work was largely ignored at the time it was published, but after Carnot's work was rediscovered more than twenty years later it became the main inspiration for subsequent work in thermodynamics.
Although he always worked on the fringes of the scientific world of his time, Sadi Carnot did not otherwise live in obscurity. His father, Lazare, was one of the most powerful men in France during the late eighteenth and early nineteenth centuries. Sadi was born in 1796 in the Paris Luxembourg Palace when Lazare was a member of the five-man executive Directory. Lazare Carnot served in highlevel positions for only about four years, but his political accomplishments and longevity were extraordinary for those turbulent times. Before joining the gov-