19th century in science Carnot captured some of the ideas of thermodynamics in his discussion of the efficiency of an idealized engine. Sadi Carnot's work provided a basis for the formulation of the first law of thermodynamics—a restatement of the law of conservation of energy—which was stated around 1850 by William Thomson, later known as Lord Kelvin, and Rudolf Clausius. Lord Kelvin, who had extended the concept of absolute zero from gases to all substances in 1848, drew upon the engineering theory of Lazare Carnot, Sadi Carnot, and Émile Clapeyron–as well as the experimentation of James Prescott Joule on the interchangeability of mechanical, chemical,
History of the Jews in 19th-century Poland History of the Jews in 19th-century Poland Jewish Polish history during the 19th century: Official Russian policy would eventually prove to be substantially harsher to the Jews than that under independent Polish rule. The lands that had once been Poland were to remain the home of many Jews, as, in 1772, Catherine II, the tzarina of Russia, instituted the Pale of Settlement, restricting Jews to the western parts of the empire, which would eventually include much Poland although it excluded some areas in which Jews had previously lived. By the late 19th century, over four million Jews would live in