Also on This Day in History April 20
Discover what happened on April 20 with HISTORY's summaries of major events, anniversaries,
famous births and notable deaths.
Births on This Day, April 20
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1928
Gerald S. Hawkins
English-American radio astronomer and mathematician who used a computer to show that Stonehenge was a prehistoric astronomical observatory.
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1860
Charles Gordon Curtis
U.S. inventor who devised a steam turbine widely used in electric power plants and in marine propulsion.
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1786
Marc Séguin the Elder
French engineer and inventor of the wire-cable suspension bridge and the tubular steam-engine boiler.
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1798
William Edmond Logan
Canadian geologist, known as the “Father of Canadian Geology.”
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1913
Willi Hennig
German zoologist who proposed cladistics (Greek=branch) for the hierarchical classification of species, based on phylogeny - the evolutionary history - of the ancestors.
Deaths on This Day, April 20
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1940
Alfred Cort Haddon
English anthropologist who is recognized as one the founders of modern British anthropology as an observational science.
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1932
Giuseppe Peano
Italian mathematician who founded symbolic logic.
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1856
Robert Livingston Stevens
U.S. engineer and ship designer who invented the inverted-T railroad rail and the railroad spike.
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1918
Ferdinand Braun
German physicist who shared the Nobel Prize for Physics in 1909 with Guglielmo Marconi for the development of wireless telegraphy.
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1786
John Goodricke
English astronomer who was the first to notice that some variable stars were periodic.