April 18 » The Greco-Turkish War is declared between Greece and the Ottoman Empire.
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.
May 26 » The original manuscript of William Bradford's history, "Of Plymouth Plantation" is returned to the Governor of Massachusetts by the Bishop of London after being taken during the American Revolutionary War.
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 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 marriage April 30, 1921
The temperature on April 30, 1921 was between 6.8 °C and 20.2 °C and averaged 13.7 °C. There was 12.0 hours of sunshine (81%). The average windspeed was 3 Bft (moderate breeze) and was prevailing from the northeast. Source: KNMI
In The Netherlands , there was from September 9, 1918 to September 18, 1922 the cabinet Ruys de Beerenbrouck I, with Jonkheer mr. Ch.J.M. Ruys de Beerenbrouck (RKSP) as prime minister.
January 20 » The first Constitution of Turkey is adopted, making fundamental changes in the source and exercise of sovereignty by consecrating the principle of national sovereignty.
February 12 » Bolsheviks launch a revolt in Georgia as a preliminary to the Red Army invasion of Georgia.
February 22 » After Russian forces under Baron Roman von Ungern-Sternberg drive the Chinese out, the Bogd Khan is reinstalled as the emperor of Mongolia.
March 8 » Spanish Prime Minister Eduardo Dato Iradier is assassinated while exiting the parliament building in Madrid.
July 27 » Researchers at the University of Toronto, led by biochemist Frederick Banting, prove that the hormone insulin regulates blood sugar.
September 5 » Roscoe "Fatty" Arbuckle party in San Francisco ends with the death of the young actress Virginia Rappe: One of the first scandals of the Hollywood community.
When copying data from this family tree, please include a reference to the origin: Eva Drenth, "Family tree Diverse", database, Genealogy Online (https://www.genealogieonline.nl/stamboom-drenth/I12466.php : accessed February 5, 2026), "Gijsbertus Hofman (1897-????)".
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