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.
August 10 » German chemist Felix Hoffmann discovers an improved way of synthesizing acetylsalicylic acid (aspirin).
August 31 » Thomas Edison patents the Kinetoscope, the first movie projector.
September 10 » Lattimer massacre: A sheriff's posse kills 19 unarmed striking immigrant miners in Lattimer, Pennsylvania, United States.
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.
December 30 » The British Colony of Natal annexes Zululand.
Day of marriage January 20, 1921
The temperature on January 20, 1921 was between 1.4 °C and 9.0 °C and averaged 6.4 °C. There was 0.2 mm of rain. The average windspeed was 4 Bft (moderate breeze) and was prevailing from the west. 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.
March 1 » Following mass protests in Petrograd demanding greater freedom in the RSFSR, the Kronstadt rebellion began, with sailors and citizens taking up arms against the Bolsheviks.
March 20 » The Upper Silesia plebiscite was a plebiscite mandated by the Versailles Treaty to determine a section of the border between Weimar Germany and Poland.
April 2 » The Autonomous Government of Khorasan, a military government encompassing the modern state of Iran, is established.
June 20 » Workers of Buckingham and Carnatic Mills in the city of Chennai, India, begin a four-month strike.
June 28 » Serbian King Alexander I proclaims the new constitution of the Kingdom of Serbs, Croats and Slovenes, known thereafter as the Vidovdan Constitution.
September 11 » Nahalal, the first moshav in Palestine, is settled as part of a Zionist plan of creating a Jewish state, later to be Israel.
Day of death February 16, 1970
The temperature on February 16, 1970 was between -6.2 °C and 1.4 °C and averaged -1.5 °C. There was 9.6 mm of rain during 5.6 hours. There was 1.5 hours of sunshine (15%). The partly or heavily clouded was. The average windspeed was 3 Bft (moderate breeze) and was prevailing from the west. Source: KNMI
When copying data from this family tree, please include a reference to the origin: Hans Weening, "Family tree Weening", database, Genealogy Online (https://www.genealogieonline.nl/stamboom-weening/I108876.php : accessed October 17, 2026), "Hepke Poelstra (1897-1970)".
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