# The New International Encyclopædia/Fourier, Jean-Baptiste Joseph, Baron

**FOURIER**, Jean-Baptiste Joseph, Baron
(1768-1830). A French geometer and physicist,
born at Auxerre. He was the son of a poor tailor,
and was left an orphan at the age of eight. The
Bishop of Auxerre, recognizing his ability, placed
him in a Church military school, where he soon
showed a decided aptitude for mathematics. At
the age of nineteen he wrote his memoir, *Sur la*
*résolution des équations numériques de degré*
*quelconque*, which was presented to the Academy
in 1789. He took part in the Revolution, but in
1795 was sent as a student to the newly founded
Ecole Normale, and soon after obtained the chair
of analysis in the Ecole Polytechnique (1795-98).
He went to Egypt in 1798 and was made
perpetual secretary of the Institute of Cairo, and in
the following year was placed at the head of one
of the two scientific expeditions to the upper
Nile. He returned to France in 1801 and was
made (1802) Prefect of Isère, a position which
he filled with his usual tact and energy.
Napoleon created him a baron in 1808; but as,
in 1814, he gave brief allegiance to the Bourbons,
his political career was wrecked by the return
of the Emperor from Elba. He was, after much
difficulty, made a member of the Academy of
Sciences in 1815, and succeeded Delambre (1822)
as perpetual secretary for the mathematical
sciences. He later became a member of the French
Academy (1826). Fourier was one of the leading
mathematical physicists of his time. His labors
were divided between the study of the theory of
heat and of numerical equations. Among his
leading works are the following: *Théorie analytique*
*de la chaleur* (1822); *Analyse des*
*équations déterminées* (posthumous, 1831); a memoir
on statics (*Journal de l'Ecole Polytechnique*,
1797-98); and numerous memoirs on equations.
His works, including references to numerous
biographical sketches, were published by Darboux
under the title, *Œuvres de Fourier* (Paris,
1889-90).

Fourier's Series, communicated by Fourier to
the Academy toward the end of 1807, plays an
important part in mathematical physics.
Consult Du Bois-Reymond, *Zur Geschichte der*
*trigonometrischen Reihen* (Tübingen, 1880).