Boltzmann, Ludwig (l

t`vĭkh bôlts`män), 1844–1906, Austrian physicist, b. Vienna, educated at Univ. of Vienna. He began teaching (1869) at Graz Univ. In 1873 he became mathematics professor at Vienna and then physics professor at Graz (1876), Munich (1890), Vienna (1895), and Leipzig (1900). Boltzmann made important contributions to the kinetic theory of gases and to statistical mechanics—the Boltzmann constant, which relates the mean total energy of a molecule to its absolute temperature, is used widely in statistics and is named for him. Working independently, he demonstrated a law on black body black body, in physics, an ideal black substance that absorbs all and reflects none of the radiant energy falling on it. Lampblack, or powdered carbon, which reflects less than 2% of the radiation falling on it, approximates an ideal black body.
..... Click the link for more information. radiation that had been stated by the Austrian physicist Josef Stefan; hence the law is sometimes known as the Stefan-Boltzmann law.

Boltzmann, Ludwig (Eduard)

(born Feb. 20, 1844, Vienna, Austria—died Sept. 5, 1906, Duino, Italy) Austrian physicist. He obtained his doctorate from the University of Vienna and thereafter taught at several German and Austrian universities. He was one of the first European scientists to recognize the importance of James Clerk Maxwell's electromagnetic theory. He explained the second law of thermodynamics by applying the laws of mechanics and the theory of probability to the motions of atoms, and he is remembered as the developer of statistical mechanics. His work was widely attacked and misunderstood; subject to depression after 1900, he eventually committed suicide. Shortly after his death, his conclusions were finally supported by discoveries in atomic physics and by recognition that phenomena such as Brownian motion could be explained only by statistical mechanics.