April 30 » J. J. Thomson of the Cavendish Laboratory announces his discovery of the electron as a subatomic particle, over 1,800 times smaller than a proton (in the atomic nucleus), at a lecture at the Royal Institution in London.
June 16 » A treaty annexing the Republic of Hawaii to the United States is signed; the Republic would not be dissolved until a year later.
July 2 » British-Italian engineer Guglielmo Marconi obtains a patent for radio in London.
September 1 » The Tremont Street Subway in Boston opens, becoming the first underground rapid transit system in North America.
September 11 » After months of pursuit, generals of Menelik II of Ethiopia capture Gaki Sherocho, the last king of Kaffa, bringing an end to that ancient kingdom.
September 12 » Tirah Campaign: In the Battle of Saragarhi, ten thousand Pashtun tribesmen suffer several hundred casualties while attacking 21 Sikh soldiers in British service.
Day of death April 10, 1931
The temperature on April 10, 1931 was between 5.8 °C and 8.8 °C and averaged 6.9 °C. There was 1.9 mm of rain during 2.1 hours. The average windspeed was 3 Bft (moderate breeze) and was prevailing from the north-northwest. Source: KNMI
In The Netherlands , there was from August 10, 1929 to May 26, 1933 the cabinet Ruys de Beerenbrouck III, with Jonkheer mr. Ch.J.M. Ruys de Beerenbrouck (RKSP) as prime minister.
January 7 » Guy Menzies flies the first solo non-stop trans-Tasman flight (from Australia to New Zealand) in 11 hours and 45 minutes, crash-landing on New Zealand's west coast.
March 26 » Swissair is founded as the national airline of Switzerland.
May 7 » The stand-off between criminal Francis Crowley and 300 members of the New York Police Department takes place in his fifth-floor apartment on West 91st Street, New York City.
September 30 » Start of "Die Voortrekkers" youth movement for Afrikaners in Bloemfontein, South Africa.
October 21 » A secret society in the Imperial Japanese Army launches an abortive coup d'état attempt.
December 9 » The Constituent Cortes approves a constitution which establishes the Second Spanish Republic.
When copying data from this family tree, please include a reference to the origin: Nabestaanden Sierd Eizenga , "Family tree Eizenga-Vis", database, Genealogy Online (https://www.genealogieonline.nl/stamboom-eizenga-vis/I7333.php : accessed February 19, 2026), "Tjeerd Hielkes Posthumus (1897-1931)".
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