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.
July 2 » British-Italian engineer Guglielmo Marconi obtains a patent for radio in London.
August 21 » Oldsmobile, an American automobile manufacturer and marque, is founded.
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.
Day of marriage November 30, 1921
The temperature on November 30, 1921 was between -15.0 °C and 1.4 °C and averaged -5.6 °C. There was 5.6 hours of sunshine (69%). The average windspeed was 3 Bft (moderate breeze) and was prevailing from the east-southeast. 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 31 » The Royal Australian Air Force is formed.
April 2 » The Autonomous Government of Khorasan, a military government encompassing the modern state of Iran, is established.
June 28 » Serbian King Alexander I proclaims the new constitution of the Kingdom of Serbs, Croats and Slovenes, known thereafter as the Vidovdan Constitution.
August 3 » Major League Baseball Commissioner Kenesaw Mountain Landis confirms the ban of the eight Chicago Black Sox, the day after they were acquitted by a Chicago court.
September 7 » In Atlantic City, New Jersey, the first Miss America Pageant, a two-day event, is held.
November 4 » Japanese Prime Minister Hara Takashi is assassinated in Tokyo.
When copying data from this family tree, please include a reference to the origin: LvH, "Genealogy De Geus", database, Genealogy Online (https://www.genealogieonline.nl/genealogie-de-geus/I43209.php : accessed August 10, 2025), "Johan Jacob KOOIJMAN (1897-????)".
Copy warning
Genealogical publications are copyright protected. Although data is often retrieved from public archives, the searching, interpreting, collecting, selecting and sorting of the data results in a unique product. Copyright protected work may not simply be copied or republished.
Please stick to the following rules
Request permission to copy data or at least inform the author, chances are that the author gives permission, often the contact also leads to more exchange of data.
Do not use this data until you have checked it, preferably at the source (the archives).
State from whom you have copied the data and ideally also his/her original source.