Arago, Francois Jean
Aiton's Encyclopedia (1910)
a'ra-go, Francois Jean (1786-1853), a French scientist. Though dead little over half a century, Arago is a marked example of the way in which eminent men and eminent services pass from the public mind. As a student, director of the Observatory of Paris, editor of the Annals of Chemistry and Physics, member of the Chamber of Deputies, Minister of War and Navy, professor in the Polytechnical School and secretary of the French Academy of Sciences, he was a brilliant, able, prominent figure for half a century. With the celebrated Biot he completed the measurements of a geographical meridian on which the scientific meter is based. Among his contributions to scientific knowledge are researches regarding the polar snows of Mars, the belts of Jupiter and Saturn, sunspots, the effects of atmospheric refraction, the oscillations of the magnetic needle , the connection between the aurora borealis and magnetism, the creation of a magnet by the use of the galvanic current, the polarization of light, the construction of a polariscope, the interference of colors, and the velocity and the wave theory of light. In the discharge of legislative and administrative duties to which he was called, Arago was influential in establishing public education, in the development of railroads and telegraphs, in improving the navigation of the Seine, and in the boring of artesian wells . He abolished flogging in the navy, and brought about the downfall of negro slavery in the French colonies. He was a brilliant writer, an eloquent speaker, a public spirited citizen, and, as we have seen, contributed in no small degree to the advancement of science.
What Has Changed in the Last Century
Aiton's 1910 sketch of Arago's life and work needs almost no correction; what has changed is his reputation, which the entry mourned as fading. The bronze statue then standing on the Place de l'Île-de-Sens was seized and melted down under the German occupation, and in 1994 the Dutch artist Jan Dibbets replaced it with 135 bronze medallions set into Paris pavements along the old meridian — the trail later made famous by Dan Brown's The Da Vinci Code (2003). His physics has held up too: the bright "Arago spot" at the centre of a circular shadow is still taught as a decisive demonstration of the wave nature of light, and his "researches regarding the polar snows of Mars" have been vindicated by spacecraft that found those caps to be water and carbon-dioxide ice. Arago's other legacies remain intact: the 1848 abolition of slavery in the French colonies came during the provisional government in which he served, and his 1839 announcement of Daguerre's photographic process to the Academy of Sciences is still cited as the birth notice of photography.
Written for this edition, 2026.