October 19

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  1433: Priest, humanist philosopher, and astrologer Marsilio Ficino born. His Florentine Academy, an attempt to revive Plato's Academy, will influence the direction and tenor of the Italian Renaissance and the development of European philosophy.

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  1900: Max Planck discovers the law of black-body radiation (Planck's law).

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  1909: Criminologist and physician Cesare Lombroso dies. Lombroso's theory of anthropological criminology essentially stated that criminality was inherited, and that someone "born criminal" could be identified by physical (congenital) defects, which confirmed a criminal as savage or atavistic.

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  1909: Physicist and chemist Marguerite Perey born. Perey will discover the element francium while purifying samples of lanthanum.

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  1910: Astrophysicist, astronomer, and mathematician Subrahmanyan Chandrasekhar born. He will share the 1983 Nobel Prize for Physics "for his theoretical studies of the physical processes of importance to the structure and evolution of the stars".

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  1973: Watergate scandal: President Richard Nixon rejects an Appeals Court decision that he turn over the Watergate tapes.