Henri Poincare

On 20 April 1881, Henri Poincaré married Louise Poulin d'Andesi, whom he had met while he was employed at the University of Caen. They had four children; Jeanne (born in 1887), Yvonne (born in 1889), Henriette (born in 1891) and Léo, (born in 1893).

Sometime in June 1912, Poincaré underwent a successful surgery for a prostate problem. Thereafter, he apparently made a good recovery. On 17 July 1912, as he was dressing to go out for the first time post-operation, he suddenly died of embolism. He was 58 year old at the time of his death.

He was buried in the Poincaré family vault in the Cemetery of Montparnasse, Paris. His funeral was attended by delegates from University of Paris, the Académie française, the Académie des Sciences etc. The Royal Society was represented by its secretary, Sir Joseph Larmor, and by the Astronomer Royal, Mr F W Dyson.

Jules Henri Poincaré was born on April 29, 1854 in Nancy, at that time an important town in the Lorraine County in France. Today it is the capital city of the French Department of Meurthe-et-Moselle.

His father, Charles Émile Léon Poincaré, was a neurologist and a Professor of Medicine at the University of Nancy. His mother, Marie Pierrette Eugénie Launois, came from a family of gentlemen farmers in Arrancy. Henry was elder of his parents’ two children, having a sister named Aline Catherine Eugénie.

At the age of five, Henry was inflicted with acute diphtheria, which caused temporary paralysis of legs and soft palate; leaving him unable to speak or walk for several months. But during this period, he also developed an auditory perception, which enabled him to associate colors with sound.

It is possible that he began his education under his mother, learning to read and write at the age of six, soon excelling in written composition. Later, he studied with a private teacher, who introduced him to mathematics.

A very intelligent boy with a strong memory, he had to read a book only once to be able to recall on which page any specific line could be found. Although music was not his strong point, he loved music and acting, staging plays with his cousins.

Starting his career as a junior lecturer in technical mathematical analysis in December 1879, Henri Poincaré remained with the University of Caen until 1881. While there, he published his first major paper, dealing with automorphic functions. It attracted the attention of many eminent mathematicians, establishing him as one.

In 1881, he joined the University of Paris as an Associate Professor of Analysis, remaining with the University for the rest of his short life. In the same year, he started working on the qualitative theory of differential equation, fully developing it by 1882, thus creating a new branch of mathematics.

Although he was thoroughly involved with his academic work, Poincaré did not totally abandon his mining career. Along with teaching at the University of Paris, he worked for the Ministry of Public Services, being employed to the position of Assistant Engineer in 1881.

From 1881 to 1885, he was in charge of development of the northern railway. Eventually, he would become Chief Engineer of the Corps de Mines in 1893 and Inspector General in 1910. Meanwhile from 1883 to 1897, he also taught mathematical analysis at École Polytechnique.

In spite of Poincare’s busy schedule, his academic output did not diminish, leading to his election to the chair of Mathematical Physics and Theory of Probability at the University of Paris in 1886. Later, he also held the chairs of Physical and Experimental Mechanics and Celestial Mechanics and Astronomy.

'La Science et l'Hypothès’ (Science and Hypothesis), first published in 1901, is one of Poincaré’s most popular works. In this book, he talked about mathematics, physics, space and nature in non-technical terms. He also declared that absolute truth is unattainable and many scientific beliefs are nothing but conventions.

'La Valeur de la Science’ (The Value of Science), published in 1905, is another of his popular works. In the first part, he dealt exclusively with the mathematical sciences, laying stress on the relationship between intuition and logic while the second part deals with the links between physics and mathematics.

'Science and Method’, published in 1908, is his third most popular book, written for general public. Here he dealt with different issues of methodology such as selection of facts, calculation of errors and methods to compensate that error etc. The book was translated into six languages.