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Французский астроном и геодезист (1630-1696). Был направлен французским правительством во Фр.Гвинею для измерения параллакса Марса в момент нахождения его в перигелии. Сравнение этих наблюдений с другими позволило определить расстояние до Марса и Солнца от Земли, что дало первую достаточно точную оценку размеров Солнечной системы. Ришер обнаружил, что маятниковый отвес качается в Гвинее медленнее, чем в Париже, из чего сделал заключение, что Гвинея дальше от центра Земли, чем Франция. Ньютон и Гюйгенс, используя эти данные, доказали, что Земля имеет форму не сферы, а сжатого сфероида. Brit, КИА, DSB.
Born: in all probability in France, 1630
Died: Paris, 1696
Dateinfo: Dates Certain
No information on financial status.
Schooling: No University
Nothing is known of the education of Richer.
Affiliation: Catholic (by assumption)
6. Scientific Disciplines
Primary: Astronomy Subordinate: Physics, Zoology The Acadщmie chose Richer to make astronomical observations far from Paris for the purpose of comparing corresponding and simultaneous observations. In 1670 he travelled to La Rochelle to measure the height of the tides in the harbor at the vernal and autumnal equinox. In the same year he made a voyage to French Canada to make observations for the Acadщmie. During this trip Richer was in charge of testing the reliability of the new marine clocks made by Huygens. Both clocks stopped during a severe storm, and Richer reported their unsuitable performance to the Acadщmie as well as to Huygens. Huygens responded that Richer was incompetent and the failure of the clocks was due to the carelessness of their caretaker rather than to the device itself. The Acadщmie did not share Huygens' estimation of Richer's ability. While off the coast of French Canada he had determined the latitude of the fort on Penobscot Bay using a quadrant with a telescopic sight. This was the most precise observation made up until that time in the Western Hemisphere. The following year Richer was selected to travel to Cayenne to make observations useful for navigation. Two years later illness forced Richer to return to Paris. For unknown reasons he was transferred from active service with the Acadщmie des Sciences to fortifications and military construction with the title of royal engineer. Richer's only written work is his "Observations astronomiques et physiques faites en l'isle de Caienne" published in the Mщmoires of the Acadщmie. Richer's astronomical observations of a lunar eclipse and the satellites of Jupiter led to the determination of the longitude of Cayenne which was three minutes too big. His observations of Mars at perigee with corresponding observations made elsewhere led to the calculation of a fairly close approximation to the fundamental astronomical unit as well as the parallax of Mars and the Sun. In geodesy Richer's observation of the length of the seconds pendulum improved the understanding of the shape of the earth as a spheroid flattened at the poles. Although Richer did not seem to have taken a great interest in describing the natural environment, he did make a few comments on the animal life. He noted that unlike the turtle the porpoise is a warm blooded animal. The crocodile can rest without food for several months even when in the presence of nourishment. Richer tried to bring a small crocodile back to France but it died on the return voyage. He also described the eels in the rivers of Cayenne. Lastly, he investigated the claims that the small opening on the back of the Pecari from which escaped a nauseating foam was related to its respiration and found this claim to be false.
7. Means of Support Primary: Government Richer spent the beginning of his career travelling for the Acadщmie and making astronomical and physical observations. After his return from Cayenne, he received the title royal engineer, but there is no information about his duties or his training in fortifications and military construction.
8. Patronage Types: Scientist, Government Official By order of Louis XIV Richer set off on his voyage to Cayenne; however the effective source of the appointment was the Acadщmie. From the general shape of his career, from his original appointment to the Acadщmie, and from the appointment as royal engineer I am assuming that
some official was taking care of Richer.
9. Technological Involvement Types: Cartography, Navigation, Military Engineering His work in cartography and navigation is above. I am assuming that he
carried out some duties as a military engineer.
10. Scientific Societies Memberships: Acadщmie Royal des Sciences, 1666-1696 Richer was admitted to the Acadщmie in 1666 as an щlшve astronome. As early as 1670 he was referred to as a mathщmaticien. By 1679 he was a full-fledged
member of the Acadщmie.
Sources 1.Alfred Lacroix, Figures de savants, 3, (Paris, 1938), pp. 11-14. 2.John W. Olmsted , "The Scientific Expedition of John Richer to Cayenne (1672-73)," Isis, 34 (1942-43), 117-28. 3.________, "The Voyage of Jean Richer to Acadia in 1670," Proceedings of the American Philosophical Society, 104 (1960),
Compiled by: Richard S. Westfall Department of History and Philosophy of Science Indiana University
The Galileo Project Development Team: firstname.lastname@example.org
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