Joseph Louis François Bertrand (French pronunciation: [ʒozɛf lwi fʁɑ̃swa bɛʁtʁɑ̃]; 11 March 1822 – 5 April 1900) was a French mathematician whose work emphasized number theory, differential geometry, probability theory, economics and thermodynamics.
Jean-Victor Poncelet (French pronunciation: [ʒɑ̃ viktɔʁ pɔ̃slɛ]; 1 July 1788 – 22 December 1867) was a French engineer and mathematician who served most notably as the Commanding General of the École Polytechnique. He is considered a reviver of projective geometry, and his work Traité des propriétés projectives des figures is considered the first definitive text on the subject since Gérard Desargues' work on it in the 17th century. He later wrote an introduction to it: Applications d'analyse et de géométrie.As a mathematician, his most notable work was in projective geometry, although an early collaboration with Charles Julien Brianchon provided a significant contribution to Feuerbach's theorem. He also made discoveries about projective harmonic conjugates; relating these to the poles and polar lines associated with conic sections. He developed the concept of parallel lines meeting at a point at infinity and defined the circular points at infinity that are on every circle of the plane. These discoveries led to the principle of duality, and the principle of continuity and also aided in the development of complex numbers.As a military engineer, he served in Napoleon's campaign against the Russian Empire in 1812, in which he was captured and held prisoner until 1814. Later, he served as a professor of mechanics at the École d'application in his home town of Metz, during which time he published Introduction à la mécanique industrielle, a work he is famous for, and improved the design of turbines and water wheels. In 1837, a tenured 'Chaire de mécanique physique et expérimentale' was specially created for him at the Sorbonne (the University of Paris). In 1848, he became the commanding general of his alma mater, the École Polytechnique. He is honoured by having his name listed among notable French engineers and scientists displayed around the first stage of the Eiffel tower.
Nicolas Léonard Sadi Carnot (French pronunciation: [nikɔla leɔnaʁ sadi kaʁno]; 1 June 1796 – 24 August 1832) was a French mechanical engineer in the French Army, military scientist and physicist, often described as the "father of thermodynamics". He published only one book, the Reflections on the Motive Power of Fire (Paris, 1824), in which he expressed the first successful theory of the maximum efficiency of heat engines and laid the foundations of the new discipline: thermodynamics. Carnot's work attracted little attention during his lifetime, but it was later used by Rudolf Clausius and Lord Kelvin to formalize the second law of thermodynamics and define the concept of entropy. Driven by purely technical concerns, such as improving the performance of the steam engine, Sadi Carnot's theoretical work laid important foundations for modern science as well as technologies such as the automobile and jet engine.
His father Lazare Carnot was an eminent mathematician, military engineer, and leader of the French Revolutionary Army.
Antoine Augustin Cournot (French pronunciation: [ɑ̃twan oɡystɛ̃ kuʁno]; 28 August 1801 – 31 March 1877) was a French philosopher and mathematician who also contributed to the development of economics.
Édouard Jean-Baptiste Goursat (21 May 1858 – 25 November 1936) was a French mathematician, now remembered principally as an expositor for his Cours d'analyse mathématique, which appeared in the first decade of the twentieth century. It set a standard for the high-level teaching of mathematical analysis, especially complex analysis. This text was reviewed by William Fogg Osgood for the Bulletin of the American Mathematical Society. This led to its translation into English by Earle Raymond Hedrick published by Ginn and Company. Goursat also published texts on partial differential equations and hypergeometric series.
Jules Antoine Lissajous (French pronunciation: [ʒyl ɑ̃twan lisaʒu]; 4 March 1822 in Versailles – 24 June 1880 in Plombières-les-Dijon) was a French physicist, after whom Lissajous figures are named. Among other innovations, Lissajous invented the Lissajous apparatus, a device that creates the figures that bear his name. In it, a beam of light is bounced off a mirror attached to a vibrating tuning fork, and then reflected off a second mirror attached to a perpendicularly oriented vibrating tuning fork (usually of a different pitch, creating a specific harmonic interval), onto a wall, resulting in a Lissajous figure. This led to the invention of other apparatus such as the harmonograph.
Antoine-Joseph Yvon Villarceau (15 January 1813 – 23 December 1883) was a French astronomer, mathematician, and engineer.
He constructed an equatorial meridian-instrument and an isochronometric regulator for the Paris Observatory.
He wrote Mécanique Céleste. Expose des Méthodes de Wronski et Composantes des Forces Perturbatrices suivant les Axes Mobiles (Paris: Gauthier-Villars, 1881) and Sur l'établissement des arches de pont, envisagé au point de vue de la plus grande stabilité (Paris: Imprimerie Impériale, 1853).
He is the eponym of Villarceau circles, which are two circular sections of a torus other than the two trivial ones.
A short street in the 16th arrondissement of Paris is named after Villarceau.
Marie Ennemond Camille Jordan (French: [ʒɔʁdɑ̃]; 5 January 1838 – 22 January 1922) was a French mathematician, known both for his foundational work in group theory and for his influential Cours d'analyse.
Félix Édouard Justin Émile Borel (French: [bɔʁɛl]; 7 January 1871 – 3 February 1956) was a French mathematician and politician. As a mathematician, he was known for his founding work in the areas of measure theory and probability.
Edmond Nicolas Laguerre (9 April 1834, Bar-le-Duc – 14 August 1886, Bar-le-Duc) was a French mathematician and a member of the Académie des sciences (1885). His main works were in the areas of geometry and complex analysis. He also investigated orthogonal polynomials (see Laguerre polynomials). Laguerre's method is a root-finding algorithm tailored to polynomials. He laid the foundations of a geometry of oriented spheres (Laguerre geometry and Laguerre plane), including the Laguerre transformation or transformation by reciprocal directions.