January 31 » Czechoslav Trade Union Association is founded in Prague.
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 22 » British colonial officers Charles Walter Rand and Lt. Charles Egerton Ayerst are assassinated in Pune, Maharashtra, India by the Chapekar brothers and Mahadeo Vinayak Ranade, who are later caught and hanged.
July 2 » British-Italian engineer Guglielmo Marconi obtains a patent for radio in London.
August 10 » German chemist Felix Hoffmann discovers an improved way of synthesizing acetylsalicylic acid (aspirin).
August 21 » Oldsmobile, an American automobile manufacturer and marque, is founded.
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.
February 21 » Constituent Assembly of the Democratic Republic of Georgia adopts the country's first constitution.
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.
March 17 » The Second Polish Republic adopts the March Constitution.
May 31 » The Tulsa race massacre kills at least 39, but other estimates of black fatalities vary from 55 to about 300.
June 20 » Workers of Buckingham and Carnatic Mills in the city of Chennai, India, begin a four-month strike.
September 7 » The Legion of Mary, the largest apostolic organization of lay people in the Catholic Church, is founded in Dublin, Ireland.
Day of death September 2, 1980
The temperature on September 2, 1980 was between 7.3 °C and 20.5 °C and averaged 14.1 °C. There was -0.1 mm of rain. There was 10.5 hours of sunshine (77%). The partly clouded was. The average windspeed was 1 Bft (weak wind) and was prevailing from the south-southeast. Source: KNMI
In The Netherlands , there was from Monday, December 19, 1977 to Friday, September 11, 1981 the cabinet Van Agt I, with Mr. A.A.M. van Agt (CDA/KVP) as prime minister.
January 26 » Egypt–Israel relations are formally established.
February 26 » Egypt and Israel establish full diplomatic relations.
April 2 » United States President Jimmy Carter signs the Crude Oil Windfall Profits Tax Act.
May 9 » In Florida, Liberian freighter MVSummit Venture collides with the Sunshine Skyway Bridge over Tampa Bay, making a 1,400-ft. section of the southbound span collapse. Thirty-five people in six cars and a Greyhound bus fall 150ft. into the water and die.
June 10 » The African National Congress in South Africa publishes a call to fight from their imprisoned leader Nelson Mandela.
September 26 » At the Oktoberfest terror attack in Munich 13 people die and 211 are injured.
When copying data from this family tree, please include a reference to the origin: Hendrik Dreyer, "Dreyer Tree", database, Genealogy Online (https://www.genealogieonline.nl/dreyer-tree/I18762.php : accessed January 23, 2026), "Roelof Jacobus Coertze (1897-1980)".
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