Geoscience Reference
In-Depth Information
The government established universal manhood suffrage in France and on Arago's
initiative abolished slavery in the French colonies. It set up national workshops to
guarantee work for everyone by implementing various public projects. Arago was
minister of war and marine, and his brother Étienne and son Emmanuel had important
posts in the same government (Emmanuel continued his distinguished career in poli-
tics long after). Arago voted with the socialists and introduced many reforms while
holding this government position, outlawing corporal punishment in the navy and
improving the condition of the sailors. Elected as President of the Commission at
the head of the Assembly, he was even the Head of State (or one could say he was the
25
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Prime Minister of France) for 46 days in 1848, a level of distinction held by
few scientists. As President he implemented an unpopular decision to abolish the
national workshops in Paris and replace them with conscription into the army. The
Commission was overthrown by a series of riots in June and July 1848 and Arago
returned to the Observatory.
Arago's dream of establishing a republic in France came to an end in 1851 in the
coup that ended the Second Republic. A year later, Louis-Napoleon re-established
the hereditary empire and took the title of Napoleon III. Arago was reluctant to
accept the reality of the new situation and refused to take the oath of allegiance to
Napoleon III. He was allowed to remain director of the Observatory until he retired
back to his birthplace in the Pyrenees in 1853.
The observations made in Spain and the Balearic Islands by Biot and Arago
were analyzed and presented by Biot in 1810 who also measured the time kept by
a pendulum clock at Bordeaux and Dunkirk. In 1817, he went to Scotland and the
Shetland Islands to confirm the geodesy carried out by Colonel William Mudge,
director of the Ordnance Survey, the most accurate and comprehensive mapping
authority in Britain. In 1813, Mudge had extended into Scotland the accurate
survey begun in England and Biot located the maps in astronomical terms of latitude
and longitude. Biot revisited Spain to repeat the geodesic measurements made by
himself and Arago and to conduct pendulum experiments. He began to realize that
the Earth was not a simple ellipsoid of revolution, and that the time kept by pendu-
lum clocks on the same latitude varied locally. His most important scientific work
was in the polarization of light, and his name is commemorated in the Biot-Savart
Law, which describes the magnetic field set up by a steady electric current and also
the Biot Number, the ratio of the rate of conduction of heat in a body and the rate
at which heat is radiated from its surface.
ARAGO WAS COMMEMORATED as a scientist and as a statesman in Paris in1893
by the erection of a bronze statue on a pedestal in the Place Île de Sein. The Place lies
south of the Observatory (on the meridian) and in the appropriately named Boulevard
Arago. The statue was taken down and melted in 1942 during the occupation of Paris
in the Second World War, and the pedestal is now empty. His body is buried in the
Cemetery of Père-Lachaise in Paris, to the east of the city center, near the entrance in
the Bvd de Ménilmontant and is commemorated there by a bust mounted on a pillar
(Division 4, to the south of the Avenue Principale between the Bureau de la
Conservation and the Monument aux Morts). In addition, a bust by Pierre-Jean David
