The temperature on May 1, 1915 was between 4.5 °C and 19.4 °C and averaged 13.2 °C. There was 7.3 hours of sunshine (49%). The average windspeed was 3 Bft (moderate breeze) and was prevailing from the southwest. Source: KNMI
In The Netherlands , there was from August 29, 1913 to September 9, 1918 the cabinet Cort van der Linden, with Mr. P.W.A. Cort van der Linden (liberaal) as prime minister.
January 25 » Alexander Graham Bell inaugurates U.S. transcontinental telephone service, speaking from New York to Thomas Watson in San Francisco.
January 31 » World War I: Germany is the first to make large-scale use of poison gas in warfare in the Battle of Bolimów against Russia.
February 19 » World War I: The first naval attack on the Dardanelles begins when a strong Anglo-French task force bombards Ottoman artillery along the coast of Gallipoli.
May 7 » The Republic of China accedes to 13 of the 21 Demands, extending the Empire of Japan's control over Manchuria and the Chinese economy.
May 7 » World War I: German submarine U-20 sinks RMS Lusitania, killing 1,198 people, including 128 Americans. Public reaction to the sinking turns many former pro-Germans in the United States against the German Empire.
June 5 » Denmark amends its constitution to allow women's suffrage.
Day of death April 23, 1964
The temperature on April 23, 1964 was between 5.2 °C and 12.3 °C and averaged 8.5 °C. There was 10.3 mm of rain during 4.4 hours. There was 2.1 hours of sunshine (15%). The heavily clouded was. The average windspeed was 3 Bft (moderate breeze) and was prevailing from the southwest. Source: KNMI
March 31 » Brazilian General Olímpio Mourão Filho orders his troops to move towards Rio de Janeiro, beginning the coup d'état.
May 9 » Ngô Đình Cẩn, de facto ruler of central Vietnam under his brother President Ngô Đình Diệm before the family's toppling, is executed.
August 16 » Vietnam War: A coup d'état replaces Dương Văn Minh with General Nguyễn Khánh as President of South Vietnam. A new constitution is established with aid from the U.S. Embassy.
August 27 » South Vietnamese junta leader Nguyễn Khánh enters into a triumvirate power-sharing arrangement with rival generals Trần Thiện Khiêm and Dương Văn Minh, who had both been involved in plots to unseat Khánh.
August 28 » The Philadelphia race riot begins.
November 21 » The Verrazano-Narrows Bridge opens to traffic. At the time it is the world's longest bridge span.
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/I486294.php : accessed February 28, 2026), "Harm Potse (± 1894-1964)".
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