Ampère, André (1775-1836)

André Ampère was the French mathematician, physicist, philosopher and chemist who played a fundamental part in founding the science of electromagnetism. Born near Lyon, France, to a wealthy family, Ampère was tutored privately. He moved to Paris in 1805 to take up a post at the Ecole Polytechnique. Three years later, he was appointed by Napoleon to be Inspector General of the Imperial university system; a post he retained until his death.

In the 1820s, Ampère's interest in electromagnetism was stimulated by Hans Christian Oersted's discovery that the flow of electric current can deflect a compass needle. Ampère realized that this phenomenon could be used in a measuring device the basis for the design of the galvanometer. Ampère investigated and theorized about many aspects of electromagnetism, showing in particular that two current-carrying wires would repel each other or attract each other depending on the direction of the current flow. If the flow of the current was the same in both wires, they would attract each other, whereas opposing current flow would cause the wires to repel. He showed that a coil of current-carrying wire, which he called a solenoid, would behave like a bar magnet. Ampère also investigated the force between two current-carrying conductors thus providing the basis for the modern definition of the SI unit of current the ampere.

Ampère had a troubled life his father was executed during the Terror of 1793 and his first wife died in 1804. These events led to a nervous breakdown from which Ampère never really recovered. His epitaph reads 'Tandem Felix' (happy at last).