Template:On This Day (nonfiction)/April 26

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  1558: Physician Jean Fernel dies. Fernel ntroduced the term "physiology" to describe the study of the body's function, and was the first person to describe the spinal canal.

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  1710: Mathematician and philosopher Thomas Reid born. Reid will argue that common sense (in a special philosophical sense of sensus communis) is, or at least should be, at the foundation of all philosophical inquiry, justifying our belief that there is an external world.

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  1798: Artist Eugène Delacroix born. His use of expressive brushstrokes and his study of the optical effects of color will shape the work of the Impressionists.

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  1879: Printer, bookseller, and inventor Édouard-Léon Scott de Martinville dies. He invented the phonoautograph, which records an audio signal as a photographic image.

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  1879: Physicist and academic Owen Willans Richardson born. He will win the 1928 Nobel Prize in Physics for his work on thermionic emission, which led to Richardson's law.

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  1902: Mathematician and academic Lazarus Immanuel Fuchs dies. He contributed important research in the field of linear differential equations. Fuchs is the eponym of Fuchsian groups and functions, and the Picard–Fuchs equation.

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  1920: Mathematician and theorist Srinivasa Ramanujan dies. He made substantial contributions to mathematical analysis, number theory, infinite series, and continued fractions, including solutions to mathematical problems considered to be unsolvable.

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  1954: Castle Union nuclear weapons test at Bikini Atoll: the United States detonates the TX-14 thermonuclear weapon, one of the first deployed U.S. thermonuclear bombs. The explosion causes extensive fallout. Castle Union was the code name given to one of the tests in the Operation Castle series of United States nuclear tests. It was the first test of the TX-14 thermonuclear weapon (initially the "emergency capability" EC-14), one of the first deployed U.S. thermonuclear bombs. Pic.

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  1986: A nuclear reactor accident occurs at the Chernobyl Nuclear Power Plant in the Soviet Union (now Ukraine).

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  2006: Yuval Ne'eman dies. Ne'eman discovered the classification of hadrons through the SU(3) flavor symmetry (now named the Eightfold Way, and proposed independently by Murray Gell-Mann).