July 5

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  1687: Isaac Newton publishes Philosophiæ Naturalis Principia Mathematica ("Mathematical Principles of Natural Philosophy"). Principia states Newton's laws of motion, forming the foundation of classical mechanics; Newton's law of universal gravitation; and a derivation of Kepler's laws of planetary motion (which Kepler first obtained empirically).

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  1833: Inventor Nicéphore Niépce dies. He invented heliography, a technique which he used to create the world's oldest surviving product of a photographic process.

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  1942: Mathematician Oskar Bolza dies. He is known for his research in the calculus of variations; his work on variations for an integral problem involving inequalities later became important in control theory.

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  2009: Discovery of the Staffordshire hoard, the largest hoard of Anglo-Saxon gold ever discovered in England, consisting of more than 1,500 items found near the village of Hammerwich, near Lichfield, Staffordshire.