Numericana's  Biographies

Pierre Louis Dulong   (1785-1838; X1801)
Wikipedia   |   Encyclopedia Britannica (1911)

An only child born in Rouen and orphaned at the age of 4, he was brought up by an aunt and was educated at Centrale-Auxerre and Centrale-Rouen.  He entered  Polytechnique  at the age of 16.  He became a physician and worked as a chemist with Berthollet in Arcueil.  He discovered the explosive properties of nitrogen chloride in 1811, losing an eye ans two fingers in the process.

In 1820, Dulong and Berzelius determined that water was an oxide of hydrogen.  Dulong held the chair of physics at  Polytechnique  from 1820 to 1829 and was director of scientific studies there from 1830 to 1838.  For his joint work with Alexis Petit  (including the formulation of the Dulong-Petit law, in 1819)  Dulong was elected to the physics section of the French  Académie des sciences  (of which he would become president, in 1828). 

Maître de conférences à Normale (1830), il est professeur de chimie en Sorbonne (1832). Il fut membre de l’Académie de médecine. Les "Lois de Dulong" ont fondé l’analyse des minerais insolubles. Il étudie la force élastique des vapeurs et la loi de Mariotte, imagine le cathétomètre et le thermomètre à poids. Dulong et Arago formulent la loi sur les machines à vapeur demandée par le gouvernement en 1825.
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Evariste Galois   (1811-1832)
MacTutor   |   The Evariste Galois Archive   |   Math93   |   Fictionalization

At the age of 20,  Evariste Galois  was mortally wounded in a duel  (with either  Perscheux d'Herbinville  or  Ernest Duchatelet)  over a young lady called  Stéphanie-Félice Poterin du Motel.  Left for dead, Galois (who had no seconds) was discovered by a local peasant and transported to the  Cochin  hospital in Paris, where he died from peritonitis the next day  (May 31, 1832).  To his brother Alfred, he had whispered:

Ne pleure pas, Alfred.  J'ai besoin de tout mon courage pour mourir à 20 ans.
Please don't cry, Alfred.  I need all my courage to die at twenty.

Held on June 2, the funerals of Galois were attended by more than 2000 people and served as a focal point of  republican  riots which lasted for several days.  His dubious status as a martyred activist could have remained Galois' main claim to fame had it not been for his wish to have his last mathematical papers reviewed by Gauss or Jacobi...  His brother,  Alfred Galois  and his closest friend  Auguste Chevalier  did send out copies of the work, which were apparently ignored by the originally intended recipients.  In 1842, one of these copies reached Joseph Liouville (1809-1882)  who finally published what is now known as  Galois Theory,  in 1846.

The story is poignant enough as it is, but some biographers are perpetuating the  myth  that Galois wrote feverishly all he knew about  Group Theory  on the night before the fateful duel, apologizing again and again for not having the time to do it better...  The leading offender is clearly E.T. Bell (1883-1960) who wrote an emphatic chapter in his popular 1937 collection of biographies entitled  Men of Mathematics.  Actually, there's only one occurence of such a statement in all the mathematical manuscripts of Galois  (an "author's note" about an incomplete proof).  Otherwise, the myth seems entirely based on the following sentence which appears in the letter known as "Galois' Testament", dated May 29, 1832 and addressed to his friend  Auguste Chevalier.  The passage is about what Galois called  ambiguity theory  (now associated with Riemann Sheets).

Mais je n'ai pas le temps, et mes idées ne sont pas encore
bien développées sur ce terrain, qui est immense. 
But I am running out of time, and my ideas are not yet
sufficiently developped in this field, which is immense.

Galois' Testament  ends with the following words:

Until the age of 12, Galois had been schooled entirely by his mother,  Adélaïde-Marie Demante Galois.  Galois was then enrolled at  Louis-le-Grand  (the most prestigious  lycée  of Paris)  as a boarder in the  quatrième  grade, on 6 October 1823.  He took his first mathematics class there (under M. Vernier) in Februay 1827 and became enthralled with the subject.  In 1828-1829, Galois was a  Mathématiques Spéciales  student under Louis Richard (1795-1849) at  Louis-le-Grand.  Athough he never published anything himself, Richard was an outstanding teacher of mathematics, in the French  Grandes Ecoles  tradition which is still enduring to this day  (see Lucien Refleu, 1920-2005).  Besides Galois, Louis Richard also taught Urbain Le Verrier (1811-1877), Joseph Serret (1819-1885) and Charles Hermite (1822-1901).

In April 1829, on the recommendation of Louis Richard, Galois had his first paper published  (Proof of a Theorem on Periodic Continued Fractions)  in the  Annales de Gergonne.  On May 25 and June 1, 1829, Galois submitted to the Academy his early research on equations of prime degree  (such an equation is solvable by radicals if and only if all its roots are rational functions of any two of them).  He was 17.

Normal Subgroups   |   Galois Rings.   |   Galois Fields

Jules Tannery   (1848-1910)
MacTutor   |   Wikipedia

Like his older brother Paul Tannery (1843-1904),  Jules Tannery  was an alumnus of the "Taupe Laplace"  (Lycée Malherbe de Caen) where he taught briefly (1871-1872) early in his career.  His star student at the time was Léon Lecornu (1854-1940) who later became a member of the  Académie des sciences.  Tannery earned his doctorate in 1874 at the  Ecole Normale Supérieure  (ENS)  under  Charles Hermite (1822-1901)  [the man who had just proved the transcendentality of  e ].

Jules Tannery  was first appointed at ENS-Ulm in 1881 and also took up lecturing duties at ENS-Sèvres in 1882, shortly ater its creation  (that counterpart of ENS-Ulm for girls had been created in 1881 and fused with ENS-Ulm in 1985).  Tannery supervised four doctoral students, including  Jacques Hadamard  (1865-1963, who proved the Prime Number Theorem)  and Jules Drach (1871-1949).

Other students of Tannery's at ENS included the likes of Paul Painlevé  (twice a Prime Minister of France, in 1917 and 1925)  and  Émile Borel (1871-1956).  Jules Tannery was elected to the French  Académie des sciences  in 1907.

Tannery devised the teardrop-shaped surface of revolution pictured at left, dubbed  Tannery's pear,  as a single lobe of the two-lobe algebraic surface  (degree 4)  of cartesian equation:

8 a² (x² + y² )  =  (a² - z² ) z²

Parametrically, for  both  lobes:
      x   =   (a / Ö32)  sin u  cos v
      y   =   (a / Ö32)  sin u  sin v
      z   =     a  sin u/2

Every  geodesic curve  (like the bold line shown at left)  is an  algebraic  closed curve  that goes around the axis  twice  and crosses itself once!

If need be, the  entire  surface described by the above unrestricted equations can be called  Tannery's hourglass  (it consists of two distinct congruent  Tannery pears  sharing the same axis and the same  cone-point ).  The cone's half-angle is:

Arctg  1/Ö8   =   19.47122...°

Jules Tannery is also remembered for  Tannery's Limiting Theorem  which states that the limit of an infinite sum is the sum of the limits, under certain conditions...

Mathematical Genealogy   |   Teaching Geometry   |   Tannery's Limiting Theorem

Ernest Vessiot   (1865-1952)
MacTutor   |   L'œuvre scientifique de M. Ernest Vessiot by Elie Cartan (1947)

In the 1884 entrance exam to the  Ecole Normale Supérieure, Vessiot was second only to  Jacques Hadamard  (1865-1963) who was subsequently a classmate of his.  After graduation, Vessiot held several teaching positions, starting at Lyon in 1887, then Lille (1892) Toulouse, Lyon again and Paris (1910).  In 1914, he succeeded  François Cosserat  (1852-1914; X1870)  as president of the  Société Mathématique de France.  Vessiot would hold the post of director of the  Ecole Normale Supérieure  until his retirement in 1935.  He was elected to the  Académie des Sciences  in 1943.

Ernest Vessiot  obtained his doctorate in 1892, under C. Emile Picard (1856-1941)  with a dissertation about the action of continuous groups of transformations  (Lie groups)  on the independent solutions of a differential equation.  In that domain, he would later extend results of Jules Drach (1902) and Elie Cartan (1907).

Mathematical Genealogy   |   Correlator

Jules Drach   (1871-1949)
MacTutor   |   Work of Jules Drach

Like  Jacques Hadamard  earlier,  Jules Drach  did his doctoral work at  Ecole Normale Supérieure  under the supervision of  Jules Tannery.

Mathematical Genealogy   |   Rues de Ludres

Yves Glénisson  (1962)

Yves-Edouard Glénisson   (1929-2011)
Doris Glénisson  |  Formules de Glénisson  |  Genealogy  |  Wikipédia

Yves Glénisson  was a Belgian mathematician and a trained engineer who was born in Louvain (Belgium) on May 3, 1929.  He was the uncle of the writer Fabienne "Amélie" Nothomb (1966-).  He inherited the title of Roman Count which had been granted in 1902 to his great-grandfather Edouard-Antoine Glénisson (1837-1904) by pope Leo XIII along with the above arms  (inspired from the  Kinschot arms).  Yves Glénisson passed away a few weeks after his eighty-second birthday, on a Sunday morning, May 29, 2011.

Yves Glénisson never bore his Belgian family arms:  De sable, à la croix pattée d'or cantonnée de douze abeilles du même, posées en pal.

Yves Glénisson is best remembered for a new way to compute the roots of a polynomial, which he published with Léon Derwidué,  in 1959.

Yves Glénisson  &  Léon Derwidué,
Une nouvelle méthode de calcul des zéros des polynômes
Acad. Roy. Belg. Bull. Cl. Sci. (5) 45 (1959) pp. 197-204.

Thanks to  Countess Doris Glénisson  (eldest daughter of Yves)  for her private communications and the permission to reproduce the above portrait of her father.

McNamee   |   Householder & Stewart, 1971   |   Glénisson & Derwidué, 1960 (pdf, 2485 kB)

Sharing Science on the Web   |   Giants of Science   |   Solvay Conferences   |   Armorial
Nicolas Bourbaki   |   Lucien Refleu   |   Roger Apéry   |   Other Biographies