Yesterday was the 231st anniversary of the birth of Cagniard de Latour, a French experimental physicist who discovered the concept of a critical state. Latour conducted a number of ingenious experiments that proved important to theoretical physics. He is best remembered for a series of tests in which he heated alcohol and other liquids in sealed glass tubes and found that at a certain critical temperature and pressure the curved upper surface of the liquid changed shape. Latour also studied the physics of voice production, estimated the forces involved in bird flight, imitated the formation of minerals in the Earth, and attempted to convert carbon into diamond.
[Source: Trevor I. Williams, Ed., A Biographical Dictionary of Scientists (John Wiley & Sons, ed. 3, New York, 1982)]