Jean-Charles de Borda

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Jean-Charles de Borda
Jean-Charles de Borda
Born(1733-05-04)4 May 1733
Dax
Died19 February 1799(1799-02-19) (aged 65)
Paris
NationalityFrench
Scientific career
FieldsMathematics
Signature

Jean-Charles, chevalier de Borda (4 May 1733 – 19 February 1799) was a French mathematician, physicist, and Navy officer.

Biography

Borda was born in the city of Dax to Jean‐Antoine de Borda and Jeanne‐Marie Thérèse de Lacroix.[1][2] In 1756, Borda wrote Mémoire sur le mouvement des projectiles, a product of his work as a

military engineer. For that, he was elected to the French Academy of Sciences
in 1764.

Borda was a mariner and a scientist, spending time in the Caribbean testing out advances in chronometers. Between 1777 and 1778, he participated in the American Revolutionary War. In 1781, he was put in charge of several vessels in the French Navy. In 1782, he was captured by the English, and was returned to France shortly after. He returned as an engineer in the French Navy, making improvements to waterwheels and pumps. He was appointed as France's Inspector of Naval Shipbuilding in 1784, and with the assistance of the naval architect Jacques-Noël Sané in 1786 introduced a massive construction programme to revitalise the French navy based on the standard designs of Sané.

In 1770, Borda formulated a ranked preferential

Napoleon Bonaparte who insisted that his own method be used after he became president of the Académie in 1801. The Borda count is in use today in some academic institutions, competitions and several political jurisdictions. The Borda count has also served as a basis for other methods such as the Quota Borda system, Black's method and Nanson's method
.

In 1778, he published his method of reducing

position fixing in pre-chronometer days. They were used, for example, by Lewis and Clark
to measure their latitude and longitude during their exploration of the North-western United States.

Another of his contributions is his construction of the standard metre, basis of the metric system to correspond to the arc measurement of Delambre and Méchain. As an instrument maker, he improved the

Méchain
.

Reflecting circle, on display at Toulon naval museum

Tables of logarithms

With the advent of the metric system, after the French Revolution it was decided that the

arc-minutes.[3] This required the calculation of trigonometric tables and logarithms corresponding to the new unit and instruments for measuring angles in the new system.[4]

Borda constructed instruments for measuring angles in the new units (the instrument could no longer be called a "sextant") which was later used in the arc measurement of the meridian between Dunkirk and Barcelona by Delambre to determine the radius of the Earth and thus define the length of the metre. The tables of logarithms of sines, secants, and tangents were also required for the purposes of navigation. Borda was an enthusiast for the metric system and constructed tables of these logarithms starting in 1792 but their publication was delayed until after his death and only published in the Year IX (1801) as Tables of Logarithms of sines, secants, and tangents, co-secants, co-sines, and co-tangents for the Quarter of the Circle divided into 100 degrees, the degree into 100 minutes, and the minute into 100 seconds to ten decimals, and including his tables of logarithms to 7 decimals from 10,000 to 100,000 with tables for obtaining results to 10 decimals.

The division of the degree into hundredths was accompanied by the division of the day into 10 hours of 100 minutes (

Republican Calendar was abolished by Napoleon in 1806, but the 400-unit circle lived on as the Gradian
.

Honours

Publications

  • Cover page of a 1791 copy of "Rapport sur le choix d'une unité de mesure" by Borda and the Marquis de Condorcet
    Cover page of a 1791 copy of "Rapport sur le choix d'une unité de mesure" by Borda and the Marquis de Condorcet
  • Page one of a 1791 copy of "Rapport sur le choix d'une unité de mesure" by Borda and the Marquis de Condorcet
    Page one of a 1791 copy of "Rapport sur le choix d'une unité de mesure" by Borda and the Marquis de Condorcet
  • Pages 2-3
    Pages 2-3
  • Pages 4-5
    Pages 4-5
  • Pages 6-7
    Pages 6-7
  • Pages 8-9
    Pages 8-9
  • Pages 10-11
    Pages 10-11
  • Final page of a 1791 copy of "Rapport sur le choix d'une unité de mesure" by Borda and the [[Marquis de Condorcet]]
    Final page of a 1791 copy of "Rapport sur le choix d'une unité de mesure" by Borda and the [[Marquis de Condorcet]]

See also

Notes

  1. ISBN 978-0-387-31022-0
    . Retrieved August 22, 2012.
  2. ^ Black, Duncan (1958). Theory of Committees and Elections. Cambridge, UK: Cambridge University Press. pp. 156ff.
  3. ISBN 978-0-486-14497-9
    . Retrieved 2022-01-02.
  4. ^ Tables Trigonométriques Décimales ou Table des Logaritihmes des Sinus, Sécantes et Tangentes, Suivant la Divisiondu Quart de Cercle en 100 degrés, du Degré en 100 Minutes, et de la Minute en 100 Secondes revues, augmentées et publiées par J. B. Delambre, Paris, AN IX (1801), L'Imprimerie de la République
  5. ^ "Discovery Circumstances: Numbered Minor Planets (175001)-(175658)". www.cfa.harvard.edu. Archived from the original on 2008-02-17.

References

Wikisource has the text of the 1911 Encyclopædia Britannica article "Borda, Jean Charles".
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