Jacques-André Mallet

Jacques-André Mallet

Jacques-André Mallet (born September 23, 1740 in Geneva ; † January 30, 1790 ibid) (also: Jacob Andreas Mallet ) was a Geneva mathematician and astronomer .

Life

Jacques-André Mallet was the son of Jean-Robert Mallet (born November 26, 1702 in Geneva; † 1771), a Geneva officer in the French service and his wife Dorothée (* 1708 in Geneva; † unknown), a daughter of François Jean Favre (1660-1740), born. His sister Marguerite Mallet was married to Jean-Louis Pictet from 1773 . Another sister was Isabelle Mallet (* 1743 in 'Geneva; † February 14, 1798).

He studied at the Académie de Genève and was a student of the mathematician Louis Necker . He then studied from 1760 to 1762 at the University of Basel with Daniel Bernoulli , with whom he corresponded until his death and who recommended him as an astronomer for Tsarina Catherine II . In 1763 he went on a study trip to France and England . In Paris he made the acquaintance of Jérôme Lalande and in London with Nevil Maskelyne and John Bevis .

With his brother-in-law Jean-Louis Pictet he was a participant in an expedition launched by Tsarina Catherine II, in which the scientists Maximilian Hell , Jeremiah Dixon , William Bayly , Anders Hellant (1717–1789) and Anders Planman (1724–1803 ) participated; he went to Lapland on April 4, 1768 to observe the passage of Venus in front of the sun on June 3, 1769 . For this purpose he participated in an observatory built in Ponoi, but was only able to observe one phase of the passage due to the weather. Jean-Louis Pictet, who was in Umba , had continuous rain. From the records, however, Jacques-André Mallet was able to determine the parallax of the sun, which made it possible to calculate the distance between the earth and the sun.

After his return to Geneva on October 29, 1769, he was elected to the Council of Two Hundred in Geneva. In 1771 he asked the council for permission to build an observatory on part of the city fortifications, which he built partly at his own expense. In the same year he received a position as honorary professor at the Académie de Genève . In 1772 he became the director of the Geneva observatory and remained so until his death. His numerous observations, which he made with the help of his assistants Marc-Auguste Pictet and Jean Trembley (1749–1811), dealt with solar and lunar eclipses , tracking Jupiter's moons, the movements of planets and comets, and sunspots .

In 1786 he decided to bring his instruments to his country house in Avully and to set up a comfortable observatory there. He now spent most of the time in his country house and, in addition to astronomy, was also concerned with the management of his estate and the business of the community in which he had been appointed cashier and village mayor.

After his death, his instruments were bought by the Geneva Société des Arts and donated to the local observatory. His country house in Avully was inscribed on the list of cultural assets .

Memberships

He was a member of the Société des Arts, founded in Geneva in 1776.

From May 2, 1772, he was a corresponding member of the Paris Académie des Sciences , from 1776 an honorary member of the St. Petersburg Academy of Sciences and a member of the Royal Society in London and the Academy of Sciences in Berlin .

Honors

The Mallet moon crater is said to have been named after him. In contrast to this, however, the Irish geophysicist Robert Mallet is also named as the namesake.

Individual evidence

1. ↑ Friedrich Schlichtegroll: Nekrolog on the year 1790, Volume 1, pp. 119–126. Retrieved February 6, 2018 . 
2. ↑ Marcel Golay: Jacques-André Mallet. In: Historical Lexicon of Switzerland . August 25, 2008. Retrieved July 29, 2018 .
3. ↑ Gaea: Natur u. Life: Central organ for the dissemination of scientific and geographical knowledge as well as progress in the field of the entire natural sciences, p. 408 . Lehmann, 1869 ( google.de [accessed July 29, 2018]).