54-467: An Aragoscope is a telescope design based on diffraction around the edge of an occluding disc, named after French scientist François Arago . The light diffracted around the edge of a perfectly circular occluder interferes constructively at the central axis, and the resolution at that point would be equal to the resolution of conventional lens with the same size as the occluder. Only light intensity would be lower. On this basis it would be possible to create
108-404: A consistent republican to the end, and after the coup d'état of 1852, though suffering first from diabetes , then from Bright's disease , complicated by dropsy , he resigned his post as astronomer rather than take the oath of allegiance . Napoleon III gave directions that the old man should be in no way disturbed, and should be left free to say and do what he liked. In the summer of 1853 Arago
162-428: A determination to carry on together further fundamental laws of the polarization of light known by their means. As a result of this work, Arago constructed a polariscope, which he used for some interesting observations on the polarization of the light of the sky. He also discovered the power of rotatory polarization exhibited by quartz . Among Arago's many contributions to the support of the undulatory hypothesis, comes
216-708: A general in the Mexican army. Jacques Étienne Victor (1799–1855) took part in Louis de Freycinet 's exploring voyage in the Uranie from 1817 to 1821, and on his return to France devoted himself to his journalism and the drama. The fourth brother, Étienne Vincent (1802–1892), is said to have collaborated with Honoré de Balzac in The Heiress of Birague , and from 1822 to 1847 wrote a great number of light dramatic pieces, mostly in collaboration. Showing decided military tastes, François Arago
270-612: A joint meeting of the academies of Arts and Sciences. In 1830, Arago also was appointed director of the Observatory, and as a member of the chamber of deputies he was able to obtain grants of money for rebuilding it in part, and for the addition of magnificent instruments. In the same year, too, he was chosen perpetual secretary of the Academy of Sciences, the place of Joseph Fourier . Arago threw himself into its service, and by his faculty of making friends he gained at once for it and for himself
324-539: A northerly wind to Bougie on the coast of Africa. Transport to Algiers by sea from this place would have occasioned a weary delay of three months; Arago, therefore, set out over land, guided by a Muslim priest, and reached it on Christmas Day. After six months in Algiers he once again, on 21 June 1809, set sail for Marseille, where he had to undergo a monotonous and inhospitable quarantine in the lazaretto , before his difficulties were over. The first letter he received, while in
378-571: A population of 11,981 (as of 1 January 2021). Its land area is 83.24 km (32.14 sq mi). It is subdivided into several civil parishes ( parròquies ), themselves subdivided into vendas ( véndes in Catalan). North of Formentera is located Espalmador (in Catalan: Illa de S'Espalmador ), the second largest island of the Pitiusas Islands, surrounded by a few minor islets. Espalmador
432-611: A single Island council, with Formentera sending a single councilor to both Parliament and the Island council). Since 2007, however, separate direct elections are held to elect the Island Council of Formentera, with currently 17 seats ( it only sends a single one to the Balearic Parliament ). Since the 1960s, Formentera has been a popular destination for hippies . Formentera is renowned across Europe for many pristine white beaches and
486-471: A starshade, specifically designed to avoid diffraction onto the central axis. Fran%C3%A7ois Arago Dominique François Jean Arago ( Catalan : Domènec Francesc Joan Aragó ), known simply as François Arago ( French: [fʁɑ̃swa aʁaɡo] ; Catalan: Francesc Aragó , IPA: [fɾənˈsɛsk əɾəˈɣo] ; 26 February 1786 – 2 October 1853), was a French mathematician , physicist , astronomer , freemason , supporter of
540-638: A telescope by placing a suitable disc in space accompanied by a separate telescope some distance away along its axis. This concept has been explored by NASA and received Phase One funding in June 2014 by the NASA Innovative Advanced Concepts (NIAC) program. It is important to note that this is a very different approach from that taken by another NASA project, the New Worlds Mission , which aims to use an occluder with "petals", otherwise known as
594-401: A touchstone for the various characters' interwoven relationships. Although paved roads allow access to all parts of the island and cars are easily hired in the port, many people choose to rent mopeds or even bicycles due to the flat nature of most of the island and the availability of dedicated cycle tracks in many locations. The island also has four Martello towers . With no airports,
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#1732858265031648-468: A worldwide reputation. As perpetual secretary it was his duty to pronounce historical eulogies on deceased members; and for this duty his rapidity and facility of thought, and his happy piquancy of style, and his extensive knowledge peculiarly adapted him. He was elected a Foreign Honorary Member of the American Academy of Arts and Sciences in 1832. In 1834, Arago again visited Scotland , to attend
702-448: Is a tombolo , separated from the main island of Formentera by a shallow sandbar . This area is a popular stopping point for those in yachts heading between Ibiza and Formentera. Formentera has a semi-arid climate with hot, very dry summers and warm, dry winters. The flat orography of the island means that rainfall is scarce and the temperature is quite uniform. The average annual rainfall is 370–420 mm. The average annual temperature
756-586: Is also fairly entitled to be regarded as having proved the long-suspected connexion between the aurora borealis and the variations of the magnetic elements. In 1827 he was elected an associated member of the Royal Institute of the Netherlands, when that institute became the Royal Netherlands Academy of Arts and Sciences in 1851, he became foreign member. In 1828, he was elected a foreign member of
810-490: Is between 17 and 18 °C. Overall, the climate is mild, with an average annual temperature of 18.6 degrees Celsius and 2883 hours of annual sunshine on average. Elections are held every four years concurrently with local elections . From 1983 to 2007, councilors were indirectly elected from the results of the election to Parliament of the Balearic Islands for the constituencies of Ibiza and Formentera (then forming
864-555: Is named after the island. James Taylor also worked on his hit song Carolina in My Mind on holiday from recording with Apple Records , though he began writing it in London and completed it on the nearby island of Ibiza . The Cap de Barbaria Lighthouse plays a pivotal role in Julio Medem 's 2001 Spanish film, Sex and Lucia (Lucía y el sexo) , which was filmed on the island and served as
918-400: Is now known as the spot of Arago . The two philosophers conducted together those experiments on the polarization of light which led to the inference that the vibrations of the luminiferous ether were transverse to the direction of motion , and that polarization consisted of a resolution of rectilinear propagation into components at right angles to each other. The subsequent invention of
972-612: Is said to derive from the Latin word frumentarium , meaning "granary". The island was occupied in prehistoric times, going back to 2,000–1,600 BC. Archaeological sites from that period remain in Ca na Costa, Cap de Barbaria (multiple sites) and Cova des Fum. The island had been occupied by the Carthaginians before passing to the ancient Romans . In succeeding centuries, it passed to the Visigoths ,
1026-773: The Byzantines , the Vandals , and the Arabs . In 1109, Formentera was the target of a devastating attack by the Norwegian king Sigurd I at the head of the Norwegian Crusade . The island was conquered by James I the Conqueror , added to the Crown of Aragon and later became part of the medieval Kingdom of Majorca . From 1403 to the early 18th century, the threat of Barbary pirate attacks rendered
1080-525: The Carbonari revolutionaries and politician. Arago was born at Estagel , a small village of 3,000 near Perpignan , in the département of Pyrénées-Orientales , France, where his father held the position of Treasurer of the Mint. His parents were François Bonaventure Arago (1754–1814) and Marie Arago (1755–1845). Arago was the eldest of four brothers. Jean (1788–1836) emigrated to North America and became
1134-672: The Mediterranean Sea . More specifically Formentera is part of the delimitation of the Balearic Sea , which is a northwestern element of the Mediterranean Sea. Its major villages are Sant Francesc Xavier , Sant Ferran de ses Roques , El Pilar de la Mola (on the La Mola peninsula), La Savina , and Es Pujols , the most important tourist destination of the island. Formentera comprises one municipality , also called Formentera, and has
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#17328582650311188-513: The Pityusic Islands group (comprising Ibiza and Formentera itself, as well as various small islets). It covers an area of 83.24 square kilometres (32.14 sq mi), including offshore islets. At the 2011 Census, the population was 10,583; according to the Census of 1 January 2021, it counted 11,891 inhabitants, while the official estimate as at 1 January 2023 was 11,389. The island's name
1242-532: The Royal Swedish Academy of Sciences . In optics, Arago not only made important optical discoveries on his own, but is credited with stimulating the genius of Jean-Augustin Fresnel , with whose history, as well as that of Étienne-Louis Malus and Thomas Young , this part of his life is closely interwoven. Shortly after the beginning of the 19th century the labours of at least three philosophers were shaping
1296-434: The experimentum crucis which he proposed to carry out for measuring directly the velocity of light in air and in water and glass. On the emission theory the velocity should be accelerated by an increase of density in the medium; on the wave theory, it should be retarded. In 1838 he communicated to the Academy the details of his apparatus, which utilized the relaying mirrors employed by Charles Wheatstone in 1835 for measuring
1350-484: The polariscope and discovery of Rotary polarization are due to Arago. He invented the first polarization filter in 1812. He was the first to perform a polarimetric observation of a comet when he discovered polarized light from the tail of the Great Comet of 1819 . The general idea of the experimental determination of the velocity of light in the manner subsequently effected by Hippolyte Fizeau and Léon Foucault
1404-442: The velocity of sound, 1818 to 1822. His magnetic observations mostly took place from 1823 to 1826. He discovered rotatory magnetism, what has been called Arago's rotations , and the fact that most bodies could be magnetized; these discoveries were completed and explained by Michael Faraday . Arago warmly supported Augustin-Jean Fresnel 's optical theories, helping to confirm Fresnel 's wave theory of light by observing what
1458-560: The Bureau des Longitudes. This, however, the prince president declined to accept, and made "an exception in favour of a savant whose works had thrown lustre on France, and whose existence the government would regret to embitter." Cape Gregory in Oregon was named by Captain Cook on 12 March 1778 after Saint Gregory , the saint of that day; it was renamed Cape Arago after François Arago. Arago remained
1512-493: The close of 1803, Arago entered the École Polytechnique , Paris, but apparently found the professors there incapable of imparting knowledge or maintaining discipline. The artillery service was his ambition, and in 1804, through the advice and recommendation of Siméon Poisson , he received the appointment of secretary to the Paris Observatory . He now became acquainted with Pierre-Simon Laplace , and through his influence
1566-399: The doctrine of the undulatory, or wave, theory of light . Fresnel's arguments in favour of that theory found little favour with Laplace, Poisson and Biot, the champions of the emission theory; but they were ardently espoused by Humboldt and by Arago, who had been appointed by the Academy to report on the paper. This was the foundation of an intimate friendship between Arago and Fresnel, and of
1620-537: The extent of its oscillations according as it is more or less approached to the surface. This discovery, which earned him the Copley Medal of the Royal Society in 1825, was followed by another, that a rotating plate of copper tends to communicate its motion to a magnetic needle suspended over it, which he called "magnetism of rotation" but (after Faraday's explanation of 1832 ) is now known as eddy current . Arago
1674-438: The fact that nude sunbathing is allowed on most of its beaches . Throughout its history, Formentera has been the subject of many legends, written in novels by famous writers such as Jules Verne , and in songs by musicians as varied as Gilberto Gil and Pink Floyd . From this artistic curiosity, the annual Formentera Jazz Festival has been held annually in early June and features many emerging and established musicians from
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1728-475: The following portions of Arago's works have appeared: Formentera Formentera ( Balearic Catalan: [fuɾmənˈteɾə] , Spanish: [foɾmenˈteɾa] ) is a Spanish island located in the Mediterranean Sea , which belongs to the Balearic Islands autonomous community ( Spain ) together with Mallorca , Menorca , and Ibiza . Formentera is the smallest and most southerly island of
1782-616: The island uninhabitable. On 17 June 1651, during the Franco-Spanish War (1635–1659) , a squadron of Spanish galleys under John of Austria the Younger captured the French galleon Lion Couronné off this island. The island and its surrounding islets became a separate insular council with the same territory as the eponymous municipality after 1977. Before that, it was administered in the former insular council of Ibiza and Formentera (covering
1836-749: The island was formerly reachable only by boat from Ibiza, making it the quieter of the two islands, but in recent years regular passenger service from the Spanish mainland has increased tourism. Ferry tickets from Ibiza are available in advance, as are transfers from Ibiza airport or port directly to accommodation in Formentera. Ferries to Formentera operate from their own terminal in Ibiza port, with departures every half hour in high season on large (200+ passenger) fast catamarans . The journey takes approximately 30 minutes comprising 10 minutes leaving Ibiza, 10 minutes crossing
1890-514: The lazaretto, was from Alexander von Humboldt ; and this was the origin of a connection which, in Arago's words, "lasted over forty years without a single cloud ever having troubled it." Arago had succeeded in preserving the records of his survey; and his first act on his return home was to deposit them in the Bureau des Longitudes at Paris. As a reward for his adventurous conduct in the cause of science, he
1944-563: The local and international scene. The Canadian writer Patrick Roscoe was born in Formentera. Joni Mitchell wrote her 1971 album Blue on the island while Bob Dylan once slept on the Far de la Mola on the island. Author Matt Haig also writes about visiting the island often in his twenties in Reasons to Stay Alive . The opening track of the King Crimson album Islands , Formentera Lady ,
1998-608: The meeting of the British Association at Edinburgh . From this time till 1848 he led a life of comparative quiet – although he continued to work within the Academy and the Observatory to produce a multitude of contributions to all departments of physical science – but on the fall of Louis-Philippe he left his laboratory to join the Provisional Government (24 February 1848). He was entrusted with two important functions, that had never before been given to one person, viz.
2052-466: The ministry of marine and colonies (24 February 1848 – 11 May 1848) and ministry of war (5 April 1848 – 11 May 1848); in the former capacity he improved rations in the navy and abolished flogging. He also abolished political oaths of all kinds and, against an array of moneyed interests, succeeded in procuring the abolition of slavery in the French colonies . On 10 May 1848, Arago
2106-437: The most creditable national enterprises, dating from this period, are due to his advocacy – such as the reward to Louis Daguerre for the invention of photography, the grant for the publication of the works of Fermat and Laplace , the acquisition of the museum of Cluny, the development of railways and electric telegraphs, the improvement of the reneile. In 1839, Arago reported the invention of photography to stunned listeners of
2160-478: The plan proposed by him. In 1830, Arago, who always professed liberal opinions of the republican type, was elected a member of the chamber of deputies for the Pyrénées-Orientales département , and he employed his talents of eloquence and scientific knowledge in all questions connected with public education, the rewards of inventors, and the encouragement of the mechanical and practical sciences. Many of
2214-553: The sea, and 10 minutes arriving in Formentera past the isthmus to Espalmador . Some of the anchorages may not be suitable for sailboats under less than ideal circumstances. A local Ibizan ( eivissenc ) variant of the Balearic dialect of the Catalan language is spoken in Formentera. While the official languages are Catalan and Spanish , other major languages like English, Italian, German, French and Dutch can also be heard extensively in
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2268-405: The southernmost point to which they were to carry the survey. Arago continued the work until 1809, his purpose being to measure a meridian arc in order to determine the exact length of a metre. After Biot's departure, the political ferment caused by the entrance of the French into Spain extended to the Balearic Islands , and the population suspected Arago's movements and his lighting of fires on
2322-445: The top of Mount Galatzó ( Catalan : Mola de l'Esclop) as the activities of a spy for the invading army. Their reaction was such that he was obliged to give himself up for imprisonment in the fortress of Bellver in June 1808. On 28 July he escaped from the island in a fishing-boat, and after an adventurous voyage he reached Algiers on 3 August. From there he obtained a passage in a vessel bound for Marseille , but on 16 August, just as
2376-491: The velocity of the electric discharge; but owing to the great care required in the carrying out of the project, and to the interruption to his labours caused by the revolution of 1848, it was the spring of 1850 before he was ready to put his idea to the test; and then his eyesight suddenly gave way. Before his death, however, the retardation of light in denser media was demonstrated by the experiments of H. L. Fizeau and B. L. Foucault, which, with improvements in detail, were based on
2430-520: The vessel was nearing Marseille, it fell into the hands of a Spanish corsair . With the rest the crew, Arago was taken to Roses , and imprisoned first in a windmill, and afterwards in a fortress, until the town fell into the hands of the French, when the prisoners were transferred to Palamos . After three months' imprisonment, Arago and the others were released on the demand of the dey of Algiers, and again set sail for Marseille on 28 November, but then within sight of their port they were driven back by
2484-458: The whole group of the Pityusic Islands), but in a separate comarca which already covered the current municipality of Formentera. This reform allowed Ibiza to unify its comarca of five municipalities with its new insular council, no longer administrating Formentera. The main island of Formentera is 19 kilometres (12 mi) long and is located about 6 kilometres (4 mi) south of Ibiza in
2538-1045: Was advised by his physicians to try the effect of his native air, and he accordingly set out to the eastern Pyrenees , but this was ineffective and he died in Paris. His grave is at the famous Père Lachaise Cemetery in Paris. Arago was an atheist. Arago's works were published after his death under the direction J. A. Barral, in 17 vols., 8vo, 1854–1862 ( F. Arago (1854), Jean-Augustin Barral (ed.), Œuvres complètes de Francois Arago (in French), Paris, Leipzig: Gide et J. Baudry, doi : 10.5962/BHL.TITLE.20983 , Wikidata Q51430135 ); also separately his Astronomie populaire , in 4 vols.; Notices biographiques , in 3 vols.; Indices scientifiques , in 5 vols.; Voyages scientifiques , in 1 vol.; Grimoires scientifiques , in 2 vols.; Mélanges , in I vol.; and Tables analytiques et documents importants (with portrait) , in 1 vol. English translations of
2592-406: Was commissioned, with Jean-Baptiste Biot , to complete the meridian arc measurements which had been begun by J. B. J. Delambre , and interrupted since the death of P. F. A. Méchain in 1804 (the meridian arc of Delambre and Méchain ). Arago and Biot left Paris in 1806 and began operations along the mountains of Spain. Biot returned to Paris after they had determined the latitude of Formentera ,
2646-824: Was elected a member of the Executive Power Commission , a governing body of the French Republic. He was made President of the Executive Power Commission (11 May 1848) and served in this capacity as provisional head of state until 24 June 1848, when collective resignation of the commission was submitted to the National Constituent Assembly. At the beginning of May 1852, when the government of Louis Napoleon required an oath of allegiance from all its functionaries, Arago peremptorily refused, and sent in his resignation of his post as astronomer at
2700-465: Was elected a member of the French Academy of Sciences , at the remarkably early age of twenty-three, and before the close of 1809 he was chosen by the council of the École Polytechnique to succeed Gaspard Monge in the chair of analytical geometry . At the same time he was named by the emperor one of the astronomers of the Paris Observatory , which was accordingly his residence till his death. It
2754-405: Was elected a member of the Bureau des Longitudes immediately afterwards, and contributed to each of its Annuals, for about twenty-two years, important scientific notices on astronomy and meteorology and occasionally on civil engineering , as well as interesting memoirs of members of the Academy. Arago's earliest physical researches were on the pressure of steam at different temperatures, and
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#17328582650312808-578: Was in this capacity that he delivered his remarkably successful series of popular lectures in astronomy, which were continued from 1812 to 1845. In 1818 or 1819 he proceeded along with Biot to execute geodetic operations on the coasts of France, England and Scotland. They measured the length of the seconds pendulum at Leith , Scotland, and in the Shetland Islands , the results of the observations being published in 1821, along with those made in Spain. Arago
2862-407: Was sent to the municipal college of Perpignan , where he began to study mathematics in preparation for the entrance examination of the École Polytechnique . Within two years and a half he had mastered all the subjects prescribed for examination, and a great deal more, and, on going up for examination at Toulouse , he astounded his examiner by his knowledge of J.-L. Lagrange 's work. Towards
2916-440: Was suggested by Arago in 1838, but his failing eyesight prevented his arranging the details or making the experiments. Arago's fame as an experimenter and discoverer rests mainly on his contributions to magnetism in the co-discovery with Léon Foucault of eddy currents , and still more to optics . He showed that a magnetic needle, made to oscillate over nonferrous surfaces, such as water, glass, copper, etc., falls more rapidly in
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