October 6

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  1570: Gerolamo Cardano imprisoned for 87 days on charges of impiety (casting a horoscope of Christ). He spent the remaining five years of his life in Rome under the eye of a suspicious pope who nonetheless gave him a pension.

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  1735: Mathematician, astronomical and scientific instrument maker Jesse Ramsden born. He will build his reputation on his engraving and design of dividing engines, which allowed high accuracy measurements of angles and lengths in instruments. Ramsden will produce instruments for astronomy that will be especially well-known for maritime use (needed for the measurement of latitudes), and for his surveying instruments (widely used for cartography and land survey).

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  1784: Mathematician, engineer, cartographer, economist, and politician Charles Dupin born. In 1826 he will create the earliest known choropleth map.

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  1831: Mathematician, philosopher, and academic Richard Dedekind born. He will make important contributions to abstract algebra (particularly ring theory), algebraic number theory and the definition of the real numbers.

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  1866: Inventor Reginald Fessenden born. He will perform pioneering experiments in radio, including the use of continuous waves and the early—and possibly the first—radio transmissions of voice and music.

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  1880: Mathematician Benjamin Peirce dies. He made contributions to celestial mechanics, statistics, number theory, algebra, and the philosophy of mathematics; he became known for the statement that "Mathematics is the science that draws necessary conclusions".

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  1889: American inventor Thomas Edison shows his first motion picture.