Template:Selected anniversaries/October 23: Difference between revisions

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||1842: Henry Harrison Chase Dunwoody born. Known in his own time for his work with the Army’s Weather Bureau, Dunwoody invented the carborundum radio detector in 1906. It was the first practical mineral radio wave detector and the first commercial semiconductor device. Pic.
||1842: Henry Harrison Chase Dunwoody born. Known in his own time for his work with the Army’s Weather Bureau, Dunwoody invented the carborundum radio detector in 1906. It was the first practical mineral radio wave detector and the first commercial semiconductor device. Pic.
||1844: Édouard Branly born ... physicist and academic, early involvement in wireless telegraphy and his invention of the Branly coherer around 1890. Pic.


||1852: De Morgan conveyed Four Color Problem to Hamilton, writing, "A student of mine asked me today to give him a reason for a fact which I did not know was a fact—and do not yet. He says that if a figure be anyhow divided and the compartments differently coloured so that the figures with any portion of common boundary line are differently coloured—four colours may be wanted, but not more… Query cannot a necessity for five or more be invented." Pic.
||1852: De Morgan conveyed Four Color Problem to Hamilton, writing, "A student of mine asked me today to give him a reason for a fact which I did not know was a fact—and do not yet. He says that if a figure be anyhow divided and the compartments differently coloured so that the figures with any portion of common boundary line are differently coloured—four colours may be wanted, but not more… Query cannot a necessity for five or more be invented." Pic.

Revision as of 04:29, 23 March 2020