Jean Baptiste Marie Charles Meusnier de la Place ( Tours, 19 June 1754 — le Pont de Cassel, near Mainz, 13 June 1793) was a French mathematician, engineer and

Revolutionary A revolutionary is a person who either participates in, or advocates a revolution. The term ''revolutionary'' can also be used as an adjective, to refer to something that has a major, sudden impact on society or on some aspect of human endeavor. ...

general. He is best known for

Meusnier's theorem In differential geometry, Meusnier's theorem states that all curves on a surface passing through a given point ''p'' and having the same tangent line at ''p'' also have the same normal curvature at ''p'' and their osculating circles form a sphere. ...

on the curvature of surfaces, which he formulated while he was at the École Royale du Génie (Royal School of Engineering). He also discovered the helicoid. He worked with

Lavoisier Antoine-Laurent de Lavoisier ( , ; ; 26 August 17438 May 1794),
CNRS (

hydrogen.

Dirigible balloon

Meusnier is sometimes portrayed as the inventor of the

dirigible An airship or dirigible balloon is a type of aerostat or lighter-than-air aircraft that can navigate through the air under its own power. Aerostats gain their lift from a lifting gas that is less dense than the surrounding air. In early ...

, because of an uncompleted project he conceived in 1784, not long after the first balloon flights of the Montgolfiers, and presented to the

French Academy of Sciences The French Academy of Sciences (French: ''Académie des sciences'') is a learned society, founded in 1666 by Louis XIV of France, Louis XIV at the suggestion of Jean-Baptiste Colbert, to encourage and protect the spirit of French Scientific me ...

. This concerned an elliptical balloon (''ballonet'') 84 metres long, with a capacity of 1,700 cubic metres, powered by three propellers driven by 80 men. The basket, in the form of a boat, was suspended from the canopy on a system of three ropes.

Jacques Charles and ''Les Frères Robert''

After their successful hydrogen balloon flights in 1783, professor Jacques Charles and the Robert brothers built an elongated, steerable craft that followed Jean Baptiste Meusnier's proposals. Their design incorporated Meusnier's internal ''ballonnet'' (air cell), a rudder, and a method of propulsion.Biographical dictionary of the history of technology, Volume 39 By Lance Day, Ian McNeil. Charles, Jacques Alexandre Cesar
/ref> On 15 July 1784 the brothers flew for 45 minutes from Saint-Cloud to Meudon with M. Collin-Hullin and Louis Philippe II, the Duke of Chartres in their elongated balloon. Rather than 80 men it was fitted with oars for propulsion and direction, but these proved useless. The absence of a gas release valve also meant that the duke had to slash the envelope to prevent it rupturing when they reached an altitude of about 4,500 metres (15,000 ft).Federal Aviation Administration - F.A.Aviation News, October 2001, Balloon Competitions and Events Around the Globe, Page 15
/ref>
/ref> On 19 September 1784 the brothers and M. Collin-Hullin flew for 6 hours 40 minutes, covering from Paris to

Beuvry Beuvry () is a commune in the Pas-de-Calais department in the Hauts-de-France region in northern France. Geography A suburban town immediately southwest of Béthune, southwest of Lille, at the junction of the D945, D72 and N41 roads. Light in ...

near Béthune, passing over Saint-Just-en-Chaussée and the region of Clermont de l’Oise.Histoire Beuvry, Balloon revolution
This was the first flight over 100 km.

Giffard's dirigible

In 1852, sixty six years after Charles and the Robert brothers 'oar powered' dirigible, Henri Giffard's design for the first successful powered airship was inspired by Meusnier's ideas.

Meusnier's military career

During his military career he was put in charge of coastal defences in 1791. Fighting the Prussians on the Rhine, he was injured during the siege of Mainz (1793) and died of his wounds.Jean-Baptiste-Marie charles meusnier de la place (1754–1793): an historical note
/ref> For his military service, his is one of the names inscribed under the Arc de Triomphe (as MEUNIER).

Notes

References

Jules Michelet Jules Michelet (; 21 August 1798 – 9 February 1874) was a French historian and an author on other topics whose major work was a history of France and its culture. His aphoristic style emphasized his anti-clerical republicanism. In Michelet's ...