Jean-Baptiste Meusnier de la Place

Project of a tethered balloon
planned by Meusnier de La Place (1784).

Jean Baptiste Marie Charles Meusnier de la Place , often simply quoted Meusnier , (born June 19, 1754 in Tours , † June 13, 1793 in Mainz-Kastel ) was a French mathematician , engineer and general .

Life and calling

Meusnier came from an old family of civil servants and lawyers in Tours. He received private lessons and attended the military academy (École royale du génie de Mézières) in Mézières in 1774/5 , where he trained as an engineer. One of his teachers there was Gaspard Monge , who encouraged him to study differential geometry . On the very first day of his arrival, Meusnier challenged Monge to test his math skills. Monge gave him the task of proving a differential geometric theorem by Euler and, to Monge's astonishment, Meusnier gave him a proof the next day that surpassed Euler's. In 1776 Meusnier published his first mathematical treatise ( Memoire sur la courbure des surfaces , Memoirs Mathem.Phys.Acad.Science, Paris, Vol. 10, 1785, pp. 477-510, read 1776) with new results on the differential geometry of curves and surfaces . Among other things, he showed that the helicoids (spiral surface) is a minimal surface . Meusnier's theorem about the curvature of curves through a point on a surface, which he proved in the same work from 1776, is named after Meusnier . Meusnier also worked with Antoine Lavoisier on electrolysis in the 1780s and was already producing hydrogen without being able to name the element. Meusnier also dealt with the theory of machines.

Military designer

In 1776 he joined the army and had a steep career. In 1792 he was commander of the 14 ^e régiment d'infantry . He was a military engineer in Verdun and Cherbourg . On May 5, 1793, Meusnier de la Place was promoted to Général de division .

Meusnier de la Place became famous when in 1784 he proposed a design for an impact airship . In the absence of previously non-existent drive units, he proposed a muscle-powered propeller for the construction, which the airship occupants should operate. In addition, Meusnier invented the so-called ballonets , which compensate for the inevitable loss of gas - a technique that is still used today. From the following year comes an airship draft that already shows all the essential components of an airship , with an elongated, streamlined shape, its own propulsion, and steerability. It was these ideas in particular that led to his admission to the French Academy of Sciences on January 3, 1784 .

Meusnier de la Place died in the fighting for the Mainspitze during the siege of Mainz by coalition troops from the wounds he suffered.

Honors

Inscription: Tué à Cassel [!]

His name is entered on the triumphal arch in Paris in the 6th column (MEUNIER).
The Meusnier Point , a headland in the Antarctic , bears his name.
In the Jardin des Prébendes d'Oé in Tour there is a monument dedicated to him with a portrait bust. The memorial inscription, however, mentions an incorrect place of death: Tué à Cassel (instead of "Castel").

literature

Richard Gillespie: Ballooning in France and Britain, 1783–1786: Aerostation and adventurism. In: Isis , Vol. 75, No. 2 (June 1984), pp. 248-268.
Clifford Truesdell: Jean-Baptiste-Marie Charles Meusnier de la Place (1754-1793): an historical note. In: Meccanica , 31, 607-610 (1996).

Web links

Biography ( Memento from October 10, 2012 in the Internet Archive )
Meusnier's theorem
To the Meusnier airship

Remarks

↑ Euler's formula, which expresses the curvature in a normal section of the surface through the two main curvatures
↑ Monge cited in Clifford Truesdell "Jean-Baptiste-Marie-Charles Meusnier de la Place (1754-1793): an historical note", Meccanica Vol. 31, 1996, pp. 607-610
↑ Meusnier's theorem: The circles of curvature of all plane sections through the same line element (i.e. point with associated tangent direction) of the surface lie on a sphere. For example Blaschke lectures on differential geometry , vol. 1, Springer 1924, paragraph 34
↑ Helmut Braun: The rise and fall of airship travel - an economic historical analysis. eurotrans-Verlag, Regensburg 2007, ISBN 3-936400-22-9 , p. 88.

personal data
SURNAME	Meusnier de la Place, Jean-Baptiste
ALTERNATIVE NAMES	Meusnier de la Place, Jean Baptiste Marie Charles
BRIEF DESCRIPTION	French mathematician and general
DATE OF BIRTH	June 19, 1754
PLACE OF BIRTH	Tours
DATE OF DEATH	June 13, 1793
Place of death	Mainz-Kastel

[1] Euler's formula, which expresses the curvature in a normal section of the surface through the two main curvatures

[2] Monge cited in Clifford Truesdell "Jean-Baptiste-Marie-Charles Meusnier de la Place (1754-1793): an historical note", Meccanica Vol. 31, 1996, pp. 607-610

[3] Meusnier's theorem: The circles of curvature of all plane sections through the same line element (i.e. point with associated tangent direction) of the surface lie on a sphere. For example Blaschke lectures on differential geometry , vol. 1, Springer 1924, paragraph 34

[4] Helmut Braun: The rise and fall of airship travel - an economic historical analysis. eurotrans-Verlag, Regensburg 2007, ISBN 3-936400-22-9 , p. 88.