Joseph Fourier (1768 - 1830)

Fourier came from a very large family. He was the ninth of twelve children - not including the three older siblings from his father’s first marriage!

By the age of ten he was an orphan. He won his first prize for maths aged only 14, but entered a Benedictine abbey intending to train as a priest. He continued to work at mathematics, and eventually decided to leave the abbey for Paris and a life devoted to research.

At this time, 1790s, he joined a local revolutionary committee, which was opposed to the monarchy. He quickly became entangled with the French Revolution, and was imprisoned in 1794 for expressing his views.

Fortunately, he was spared the guillotine and was freed later that year. He went to study at the École Normale in Paris with Laplace, Lagrange and Monge, and later began teaching at the École Polytechnique.

However, his political background caught up with him and he was arrested and imprisoned again only to be released shortly afterwards.

He was a scientific adviser for Napoleon’s army when it invaded Egypt in 1798, along with Monge. Although the battle started promisingly for Napoleon, by the end of the year the fleet was almost totally destroyed by Nelson in the Battle of the Nile.

Napoleon’s army were trapped in Egypt. Fourier became an administrative figure, and helped set up schools and archaeological digs, and collate the information found.

He founded the Cairo Institute, where along with Monge and Napoleon, he was one of the twelve members of the maths division! He was elected secretary.

Napoleon returned to Paris in 1799, Fourier following him a couple of years later, taking up his old post at the École Polytechnique. Napoleon so valued Fourier that he appointed him as Prefect of the Department of Isère, and he moved to Grenoble.

Although a great honour, Fourier really wanted to pursue his mathematical research. Instead he ended up overseeing swamp drainage and road construction.

He also wrote the Description of Egypt during this time, although by the time of its publication in 1810 Napoleon had made so many changes that he’d almost rewritten history! By the second edition nearly all references to Napoleon had been removed.

He also worked on his theory of heat in a memoir entitled On the Propagation of Heat in Solid Bodies, which caused controversy when he sent it to a committee consisting of Laplace, Lagrange, Monge and Lacroix.

It was the first appearance of what we now call Fourier series - the expansion of functions by trigonometric series. He won a prize for his work, although the board were not entirely convinced by his detailed analysis.

Subsequently his work was completely vindicated and became the fundamental method of dealing with waves and their propagation and as this includes sound, optics, electronics you can see how important it is.

When Napoleon fled to exile in Elba, he made Fourier Prefect of the Rhône. Fourier resigned after being ordered to remove all administrators with Royalist sympathies.

Fortunately, Napoleon allowed him to retain a pension of 6000 francs. Unfortunately Napoleon was defeated before the pension came in to effect and Fourier returned to Paris penniless.

He continued his mathematical research, and was elected to the French Academy of Sciences against a rival called Biot. Later, Biot would contest Fourier’s work on heat, claiming that he had discovered it first, although he could not prove it.