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 anatomy in the 19th century History of anatomy in the 19th century The history of anatomy in the 19th century saw anatomists largely finalise and systematise the descriptive human anatomy of the previous century. The discipline also progressed to establish growing sources of knowledge in histology and developmental biology, not only of humans but also of animals. Samuel Thomas von Sömmerring originally published a clear, accurate and precise system in German (1791–1796), then in Latin (1794–1800). There was a second German edition in 1800–1801 and a further eight-volume edition (1841–1844) revised and with additional material by Th.L.W. Bischoff, Friedrich Gustav Jakob Henle, E.H. Huschke, Theile,