Fourier, Joseph, << foo ryay, zhoh ZEHF, >> Baron (1768-1830), a French mathematician, studied the theory of heat conduction and developed a technique for describing the transfer of heat in purely mathematical terms. Fourier was also a political administrator and accompanied the French general Napoleon Bonaparte on a campaign in Egypt.
Jean-Baptiste-Joseph Fourier was born in Auxerre, France, on March 21, 1768. He studied at the Royal Military School in Auxerre, where he later returned as a teacher. In 1787, he entered the abbey of St. Benoit-sur-Loire to train for the priesthood, but he left the abbey after two years. In 1793, Fourier became involved in the French Revolution (1789-1799). Because of his political activities, he was imprisoned for several months in 1794 and again in 1795. Fourier joined the Ecole Normale in Paris, a teacher-training college, when it opened in 1795. Later in the same year, he became a professor of mathematics at the new Ecole Polytechnique, also in Paris.
In 1798, Fourier went with Napoleon’s invasion force to Egypt as a scientific adviser. See Napoleon I (Egypt invaded). As an administrator in Egypt, Fourier set up and supervised a number of scientific and educational institutions. He returned to France in 1801 and was appointed to the administrative post of prefect of Isere at Grenoble in the following year. He stayed in Grenoble until Napoleon was defeated in 1815, when he moved to Paris. Fourier was elected to the French Academy of Sciences in 1817 and became its secretary in 1822. In 1826, he was elected to the French Academy and to the Academy of Medicine. He became a member of the Royal Society (London) in 1823. In 1830, he was elected a foreign member of the Royal Swedish Academy of Sciences.
Fourier began his mathematical work on the theory of heat conduction in the early 1800’s. He presented his first paper on the subject, “On the propagation of heat in solid bodies,” to the French Academy of Sciences in 1807. This paper introduced the technique of expressing mathematical functions (relationships between variables) as trigonometric series (series of sines and cosines). These trigonometric series are now known as Fourier series. His technique had a great influence in mathematical physics and in pure mathematical analysis. Fourier series are used in physics in the study of light, sounds, and other waves. He was awarded the title of baron by Napoleon in 1808 and, in 1812, he won the mathematics prize of the French Institute. His completed theory appeared as The Analytical Theory of Heat (1822). Fourier’s work aroused some controversy because mathematicians of the time disagreed over the degree of generality of Fourier series. These difficulties provided a stimulus for mathematicians to clarify the analysis of functions. Fourier died in Paris on May 16, 1830.
