Dominique François Arago biography

Dromo's Den

Dominique Francois Arago Biography

Arago, Dominique Francois (1786-1853). A celebrated French astronomer and natural philosopher, born at Estagel, near Perpignan, in the Department of Basses-Pyrénées. At the age of 17 he entered the Ecole Polytechnique at Paris, where the spirit, promptitude, and vivid intelligence he exhibited in his answers to the questions of Legendre excited the admiration of every one. In 1805 he became secretary to the Bureau des Longitudes at Paris. Two years afterward he was engaged, with Biot and others, by the French government, to carry out the measurement of an are of the meridian, which had been commenced by Delambre and Méchain. Arago and Biot had to extend it from Barcelona to the Balearic Islands. The two savants established themselves on a lofty summit near the eastern coast of the Spanish peninsula, where they lived for many months, communicating by signals across the Mediterranean with their Spanish collaborators in the little isle of Iviza. Before Arago completed his calculations, Biot had returned to France, and war had broken out between France and Spain. Arago was now held to be a spy; his signals were interrupted; and with great difficulty he succeeded in making his escape to Majorca, where he voluntarily imprisoned himself in the citadel of Belver, near Palma. At last he obtained his liberty on condition of proceeding to Algiers, which he did; but on his way back to France was captured by a Spanish cruiser, and sent to the hulks at Palamos. He was, however, liberated after a time and sailed once more for France; but almost as he was entering the port of Marseilles, a tempest arose which drove the vessel across the Mediterranean all the way back to the coast of Africa, landing it at Bougia. He went by land to Algiers, where he was compelled to remain about half a year, and whence he again set out for Marseilles in the latter part of June, 1809. After having narrowly escaped another capture by an English frigate, Arago finally found his way to Marseilles. As a reward for his sufferings in the cause of science, the Paris Academy of Sciences suspended its standing rules in his favor; and though only 23 years of age, he was elected member in the place of Lalande, who had just died, and was appointed professor of analytical geometry and geodesy in the Ecole Polytechnique. Afterward his attention was devoted more to astronomy, magnetism, galvanism, and polarization of light. In 1811 he read before the Academy a paper of fundamental importance on chromatic polarization. In 1812 he began his extraordinary course of lectures on astronomy, etc., which fascinated all Paris-- the savants by their scientific rigor and solidity, the public by their brilliancy of style. In 1816, along with Gay-Lussac, Arago established the Annales de Chimie et de Physique and demonstrated the value of the undulatory theory of light. In the same year he visited England, making the acquaintance of various persons distinguished in science, especially Dr. Thomas Young. In 1818 appeared his Recueil d'observations géodésiques, astronomiques, et physiques. In 1820 he turned his facile and inventive genius into a new channel and made several important discoveries in electromagnetism. Oersted had shown that a magnetic needle was deflected by a voltaic current passing along a wire. Arago pursued the investigation and found that not only a magnetic needle, but even non-magnetic substances, such as rods of iron or steel, were subject to deflection, exhibiting during the action of the voltaic current a positive magnetic power, which, however, ceased with the cessation of the current. Some time after, he demonstrated that a bar of copper and other non-magnetic metals, when moved circularly, exert a noticeable influence on the magnetic needle. For this discovery of the development of magnetism by rotation, he obtained in 1825 the Copley Medal of the Royal Society of London, and in 1834, when he again visited Great Britain, especial honors were paid to him by the friends of science in Edinburgh and Glasgow. Four years previous to this second visit to Great Britain he was made perpetual secretary of the Academy and director of the observatory, a position which he retained till his death. As secretary of the Academy he wrote his famous éloges of deceased members, the beauty of which has given him so high a place among French prose writers. In politics, too, his career was remarkable. He was a keen Republican and took a prominent part in the July Revolution of 1830. In the following year he was elected by Perpignan as member of the Chamber of Deputies, where he occupied a position on the extreme Left. In the February Revolution of 1848 he was chosen a member of the Provisional government, and appointed Minister of War and Marine. In this position he resisted the proposed measures of the Socialist party, regarding the Constitution of the United States as the ideal of democracy. His popularity in his own department was the means of preventing the discontented population of Basses-Pyrénées from proceeding to lawless and violent measures. He opposed the election of Louis Napoleon to the presidency, declared himself against the policy of the new ministry, and refused to take the oath of allegiance after the coup d'etat of 1851. Napoleon, in a letter, paid a high tribute to his talents and virtues and excused him from taking the oath as director of the observatory. In his general character Arago was sociable and a brilliant conversationalist. He was the intimate friend of Alexander von Humboldt. His collected works, edited by Barral, were published in Paris (17 vols., including a biography of Arago, 1854-62) . Alexander von Humboldt wrote an introduction to the German translation of Arago's works.

The New International Encyclopaedia, Vol. II (New York: Dodd, Mead & Co., 1920) 2-3.