Francois Arago (1786-1853), French physicist and astronomer. Arago laid many of the foundations for the study of electromagnetism, studying magnetic rotation and the magnetisation of a wire coil by passing electrical current through it. His experimental discoveries of the behaviour of an oscillating magnetic needle won him the Copley Medal of the Royal Society in 1825. He also worked with Jean Baptiste Biot to measure the Earth's meridians. This led to the original standardisation of the metre as 1/10,000,000 the distance from the equator to the North Pole through Paris. A liberal republican, he held several roles in government during his career.