Rudolf Julius Emanuel Clausius
(1822 - 1888)

born: January 2, 1822 in Kölin died: August 24, 1988 in Bonn German physicist. R. Clausius was professor in Zürich, Würzburg, Bonn and was one of the founders of statistical mechanics. ("Über die Art der Bewegung, welche wir Wärme nennen") He formulated the second law of thermodynamics and introduced the entropy as equation of state. In his work "Über die bewegende Kraft der Wärme und die Gesetze, welche sich daraus ableiten lassen" (Poggendorffs "annalen", 1850) he defines the elements of classical thermodynamics, with all major implications of the mechanical equivalent of heat. He modified Carnot's law such, that the work produced by heat is not only proportional to the heat transferred from the warmer to the colder body, but is also proportional to the temperature difference of the two bodies. His major publications are the "Abhandlungen über die mechanische Wärmetheorie" (Braunschweig, 1864-67). Second Edition in three volumes: Vol. 1: "Die mechanische Wärmetheorie", (1876), Vol. 2: "Die mechanische Behandlung der Elektrizität" (1879), Vol. 3: "Entwicklung der besonderen Vorstellung von der Natur der Wärme als eine Art der Bewegung" (later edited by Planck and Pulfrich as "Kinetische Theorie der Gase" (1889-91)).