Fourier, Joseph (1768–1830)

JOSPEH FOURIER WAS a French mathematician, also acknowledged as an Egyptologist and administrator, who greatly influenced mathematical physics through his Théorie analytique de la chaleur (1822; The Analytical Theory of Heat). He analyzed the con-duction [Page 427]of heat in solid bodies in terms of infinite mathematical series now called the Fourier series. His work went well beyond the area of heat conduction, stimulating research in mathematical physics. Since Fourier, the discipline has been identified with the solution of boundary-value problems, focusing on many natural occurrences such as sunspots, tides, and the weather. Fourier has also contributed to the theory of functions of a real variable, one of the main branches of modern mathematics. The mathematician was one of the earliest proponents of the theory of global warming, although his many other achievements have overshadowed such contribution. In an article first published in 1824, Fourier pioneered the study of global warming, arguing that the atmosphere absorbs some of the Sun's warmth and sends it back to the Earth.

Fourier was born on March 21, 1768 in Auxerre, Bourgogne, France, the ninth of 12 children from his father's second marriage. His childhood was marked by the premature death of both his parents. His mother died when he was 9 years old and his father, a tailor, died the following year. Fourier started his education at Pallais's school, run by the music master from the cathedral. Because of the great potential that he had shown, he proceeded, in 1780, to the Ecole Royale Militaire of Auxerre where first he excelled in literature, but very soon understood that his favorite field was mathematics.

In 1787, Fourier entered the Benedictine abbey of St Benoit-sur-Loire to become a priest. His interest in mathematics continued, however, and Fourier was not completely sure that training for the priesthood was the right decision. In his correspondence with C. L. Bonard, the professor of mathematics at Auxerre, he admitted that he really wanted to make a major impact in mathematics. In the end, Fourier did not take his religious vows and left St Benoit in 1789. The following year, he found employment as a teacher at the Benedictine college, Ecole Royale Militaire of Auxerre, where he had studied. With the outbreak of the French Revolution, political commitment also entered Fourier's life, and, in 1793, the mathematician became involved in politics and joined the local Revolutionary Committee. Fourier was “enamored,” as he wrote, of the ideal of equality that pervaded the Revolution at the beginning, although he was appalled by the excesses that soon characterized the Terror.

After being briefly imprisoned due to internal feuds within the Revolutionary Front, later in 1794, Fourier was accepted to study at the Ecole Normale in Paris. This institution had been established for training teachers, and was intended to serve as a model for other teacher-training schools. Fourier began teaching at the Collège de France and, thanks to his contacts with Lagrange, Laplace and Monge, who had been his teachers at the Normale, began further mathematical research. He was appointed to a position at the Ecole Centrale des Travaux Publiques. After a second arrest, in 1975, Fourier went to teach at the Ecole Polytechnique. In 1797, he succeeded Lagrange as chair of analysis and mechanics.

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