César-François Cassini de Thury explained

César-François Cassini de Thury
Birth Date:17 June 1714
Birth Place:Thury-sous-Clermont, France
Death Place:Paris, France
Children:Jean-Dominique Cassini
Nationality:French
Field:Cartography
Astronomy
Work Institutions:Paris Observatory
Known For:Topographical map of France

César-François Cassini de Thury (17 June 1714  - 4 September 1784), also called Cassini III or Cassini de Thury, was a French astronomer and cartographer.

Biography

Cassini de Thury was born in Thury-sous-Clermont, in the Oise department, the second son of Jacques Cassini and Suzanne Françoise Charpentier de Charmois.[1] He was a grandson of Giovanni Domenico Cassini, and would become the father of Jean-Dominique Cassini, Comte de Cassini.[2]

In 1739, he became a member of the French Academy of Sciences as a supernumerary adjunct astronomer, in 1741 as an adjunct astronomer, and in 1745 as a full member astronomer.

In January 1751, he was elected a Fellow of the Royal Society.[3]

Cassini de Thury succeeded to his father's official position in 1756 and continued the hereditary surveying operations.[4] In 1744, he began the construction of a great topographical map of France, one of the landmarks in the history of cartography. Completed by his son Jean-Dominique, and published by the Académie des Sciences from 1744 to 1793, its 180 plates are known as the Cassini map.

The post of director of the Paris Observatory was created for his benefit in 1771 when the establishment ceased to be a dependency of the French Academy of Sciences. A letter and proposal sent by Cassini de Thury to the Royal Society in London instigated the Anglo-French Survey (1784–1790), which measured the precise distance and direction between the Paris Observatory and the Royal Observatory, Greenwich, by way of a trigonometric survey.

His chief works are: La méridienne de l’Observatoire Royal de Paris (1744), an arc measurement correction of the Paris meridian (Dunkirk-Collioure arc measurement (Cassini de Thury and de Lacaille)); Description géométrique de la terre (1775); and Description géométrique de la France (1784), which was completed by his son ("").

César-François Cassini de Thury died of smallpox in Paris on 4 September 1784.

Works

Bibliography

D. Aubin, Femmes, vulgarisation et pratique des sciences au siècle des Lumières : Les Dialogues sur l’astronomie et la Lettre sur la figure de la Terre de César-François Cassini de Thury, Brepols (2020)

See also

External links

Notes and References

  1. Jonathan Powell, From Cave Art to Hubble: A History of Astronomical Record Keeping, (Springer Nature Switzerland AG, 2019), 114
  2. Jonathan Powell, From Cave Art to Hubble: A History of Astronomical Record Keeping, (Springer Nature Switzerland AG, 2019), 115
  3. Web site: Library and Archive Catalogue. Royal Society. 21 December 2010.
  4. Jonathan Powell, From Cave Art to Hubble: A History of Astronomical Record Keeping, (Springer Nature Switzerland AG, 2019), 115