The temperature on June 9, 1884 was about 14.5 °C. There was 0.9 mm of rain. The air pressure was 1 kgf/m2 and came mainly from the west-southwest. The airpressure was 76 cm mercury. The atmospheric humidity was 78%. Source: KNMI
In The Netherlands , there was from April 23, 1884 to April 21, 1888 the cabinet Heemskerk, with Mr. J. Heemskerk Azn. (conservatief) as prime minister.
February 1 » The first volume (A to Ant) of the Oxford English Dictionary is published.
May 1 » Moses Fleetwood Walker becomes the first black person to play in a professional baseball game in the United States.
June 16 » The first purpose-built roller coaster, LaMarcus Adna Thompson's "Switchback Railway", opens in New York's Coney Island amusement park.
October 14 » George Eastman receives a U.S. Government patent on his new paper-strip photographic film.
October 22 » The International Meridian Conference designates the Royal Observatory, Greenwich as the world's prime meridian.
December 6 » The Washington Monument in Washington, D.C., is completed.
Day of marriage May 6, 1911
The temperature on May 6, 1911 was between 2.7 °C and 13.9 °C and averaged 8.6 °C. There was 12.1 hours of sunshine (80%). The average windspeed was 3 Bft (moderate breeze) and was prevailing from the north. Source: KNMI
January 3 » A magnitude 7.7 earthquake destroys the city of Almaty in Russian Turkestan.
January 12 » The University of the Philippines College of Law is formally established; three future Philippine presidents are among the first enrollees.
January 18 » Eugene B. Ely lands on the deck of the USSPennsylvania anchored in San Francisco Bay, the first time an aircraft landed on a ship.
February 18 » The first official flight with airmail takes place from Allahabad, United Provinces, British India (now India), when Henri Pequet, a 23-year-old pilot, delivers 6,500 letters to Naini, about 10 kilometres (6.2mi) away.
July 7 » The United States, UK, Japan, and Russia sign the North Pacific Fur Seal Convention of 1911 banning open-water seal hunting, the first international treaty to address wildlife preservation issues.
December 29 » Mongolia gains independence from the Qing dynasty, enthroning 8th Jebtsundamba Khutughtu as Khagan of Mongolia.
Day of death December 21, 1931
The temperature on December 21, 1931 was between -1.2 °C and 2.0 °C and averaged 0.4 °C. The average windspeed was 3 Bft (moderate breeze) and was prevailing from the east-northeast. Source: KNMI
In The Netherlands , there was from August 10, 1929 to May 26, 1933 the cabinet Ruys de Beerenbrouck III, with Jonkheer mr. Ch.J.M. Ruys de Beerenbrouck (RKSP) as prime minister.
February 20 » The U.S. Congress approves the construction of the San Francisco–Oakland Bay Bridge by the state of California.
March 5 » The British Raj: Gandhi–Irwin Pact is signed.
March 23 » Bhagat Singh, Shivaram Rajguru and Sukhdev Thapar are hanged for the killing of a deputy superintendent of police during the Indian independence movement.
March 25 » The Scottsboro Boys are arrested in Alabama and charged with rape.
March 26 » Swissair is founded as the national airline of Switzerland.
October 1 » Clara Campoamor persuades the Constituent Cortes to enfranchise women in Spain's new constitution.
When copying data from this family tree, please include a reference to the origin: J. Ham, "Family tree Ham", database, Genealogy Online (https://www.genealogieonline.nl/stamboom-ham/I1500.php : accessed February 1, 2026), "Roelf Potze (1884-1931)".
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