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 2 » Anglo-Afghan War: The Siege of Malakand ends when a relief column is able to reach the British garrison in the Malakand states.
August 10 » German chemist Felix Hoffmann discovers an improved way of synthesizing acetylsalicylic acid (aspirin).
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.
December 30 » The British Colony of Natal annexes Zululand.
Day of marriage February 25, 1921
The temperature on February 25, 1921 was between -2.9 °C and 14.0 °C and averaged 4.8 °C. There was 8.6 hours of sunshine (81%). The average windspeed was 2 Bft (weak wind) and was prevailing from the south. 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 » The Australian cricket team captained by Warwick Armstrong becomes the first team to complete a whitewash of The Ashes, something that would not be repeated for 86 years.
April 11 » Emir Abdullah establishes the first centralised government in the newly created British protectorate of Transjordan.
May 3 » West Virginia becomes the first state to legislate a broad sales tax, but does not implement it until a number of years later due to enforcement issues.
July 2 » World War I: U.S. President Warren G. Harding signs the Knox–Porter Resolution formally ending the war between the United States and Germany.
October 13 » Soviet republics sign the Treaty of Kars to formalize the borders between Turkey and the South Caucasus states.
October 26 » The Chicago Theatre opens.
Day of death April 2, 1952
The temperature on April 2, 1952 was between -2.0 °C and 6.6 °C and averaged 2.2 °C. There was 1.1 mm of rain during 0.9 hours. There was 7.1 hours of sunshine (55%). The partly clouded was. The average windspeed was 3 Bft (moderate breeze) and was prevailing from the northwest. Source: KNMI
April 9 » Hugo Ballivián's government is overthrown by the Bolivian National Revolution, starting a period of agrarian reform, universal suffrage and the nationalization of tin mines
June 26 » The Pan-Malayan Labour Party is founded in Malaya, as a union of statewide labour parties.
July 7 » The ocean liner SSUnited States passes Bishop Rock on her maiden voyage, breaking the transatlantic speed record to become the fastest passenger ship in the world.
July 21 » The 7.3 Mw Kern County earthquake strikes Southern California with a maximum Mercalli intensity of XI (Extreme), killing 12 and injuring hundreds.
September 6 » A prototype aircraft crashes at the Farnborough Airshow in Hampshire, England, killing 29 spectators and the two on board.
October 8 » The Harrow and Wealdstone rail crash kills 112 people.
When copying data from this family tree, please include a reference to the origin: Joop Klavers, "Family tree Klavers", database, Genealogy Online (https://www.genealogieonline.nl/stamboom_klavers/I155243.php : accessed March 16, 2026), "Derk Roossien (1897-1952)".
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