Page:Encyclopædia Britannica, Ninth Edition, v. 1.djvu/793

Rh A M P A M P 749 tionary excesses, was at once thrown into prison, and soon after perished on the scaffold. This event produced such an impression on the susceptible mind of Ampere, that he continued for more than a year in a state little removed from idiocy. But Rousseau s letters on botany falling into his hands, the subject engrossed him, and roused him from his apathy. His passion for knowledge returned. From botany he turned to the study of the classic poets, and to the writing of verses himself. About this time (1796) an attachment sprang up, the progress of which he naively recorded in a journal (Amorum). In 1799 he was happily married to the object of his attachment. From about 1796 Ampere gave private lessons at Lyons in mathe matics, chemistry, and languages; and in 1801 he removed to Bourg, as professor of physics and chemistry, leaving his ailing wife and infant son at Lyons. His wife died in 1804. After two years absence he returned to Lyons, on his appointment as professor of mathematics at the Lyceum. His small treatise, Considerations sur la Theorie Mathematique du Jeu (Lyons, 1802), in which he success fully solved a problem that had occupied Buffon, Pascal, and others, and demonstrated that the chances of play are decidedly against the habitual gambler, attracted consider able attention. It was this work that brought him under the notice of M. Delambre, whose recommendation obtained for him the Lyons appointment, and afterwards (1805) a subordinate position in the Polytechnic School at Paris, where he was elected professor of analysis in 1809. Here he continued to prosecute his scientific researches and his multifarious studies with unabated diligence. He was admitted a member of the Institute in 1814. It is on the service that he rendered to science in establishing the rela tions between electricity and magnetism, and in developing the science of electro-magnetism, or, as he called it, electro dynamics, that Ampere s fame mainly rests. On the llth of September 1820 he heard of the discovery of Professor Oersted of Copenhagen, that a magnetic needle may be deflected by a voltaic current. On the 18th of the same month he presented a paper to the Academy, containing a far more complete exposition of the phenomenon, which he had in the interval investigated by experiment, and show ing that magnetic defects can be produced, without magnets, by aid of electricity alone. In particular he showed that two wires connecting the opposite poles of a battery attract or repel each other according as the currents pass in the same or in opposite directions. According to the theory of magnetism which Ampere s subsequent investigations led him to adopt, every molecule of magnetic matter is acted on by a closed electric current, and magnetisation takes place in proportion as the direction of these currents approaches parallelism. The whole field thus opened up he explored with characteristic industry and care. He anticipated the invention of the electric telegraph, having suggested in 1821 an apparatus of the kind with a sepa rate wire for each letter. Late in life he prepared a remarkable work on the classification of the sciences, which was published after his death. In addition to this and one or two works of less importance, he wrote a great number of memoirs and papers that appeared in scientific journals. He died at Marseilles in June 1836. The great amiability and child-like simplicity of Ampere s character are well brought out in his Journal et Correspondence, published by Madame Chevreux (Paris, 1872). AMPERE, JEAN-JACQUES-ANTOINE, the only child of the preceding, was born at Lyons, August 12, 1800. He showed an early preference for literary pursuits, and this was strengthened by his intimate intercourse with the brilliant circle to which his introduction to Madame Re&quot;camier s celebrated reunions admitted him. He be-an his literary career as a contributor to the Globe and Seme Francaise, which Guizot conducted in opposition to the government of Charles X. After spending some time in travel, he commenced a course of lectures at the Athenaeum of Marseilles in 1830, the first of which, De I Histoire de la Poesie, he published. The revolution of July led to his return to Paris, where he lectured at the Sorbonne, till, in 1833, he succeeded Andrieux as professor of the history of French literature in the college of France. His lectures here, which were greatly admired, form the basis of several works, particularly of his Histoire litteraire de la France avant Ie_l2me Siecle, 3 vols., Paris, 1839, 1840. Ampere was a constant contributor to various periodical publica tions. He wrote for the Revue des Deux Mondes sprightly accounts of his long journeys in Egypt and North America, as well as in various parts of Europe, which were after wards collected under the title, Litterature et Voyages (2 vols., 1834). His principal work is the Histoire Romaiiif a Rome (4 vols., 1856-64), a series of papers, reprinted in part from the Revue des Deux Mondes, showing shrewd sense and great and varied learning, particularly on archaeological questions, and written in an attractive though often discursive style. Ampere was officer of the Legion of Honour from 1846, and in 1847 was admitted to the French Academy. He died March 27, 1864. AMPHIARAUS, in Greek legend, a son of Oi cles and Hypermnestra, descended on the paternal side from, the kingly seer Melampus, and, like his ancestor, endowed with the prophetic gift ; but at the same time known for his valour in the great enterprises of his time the expedition of the Argonauts and the hunt of the Calydonian boar. The expedition, however, on which the chief events of his life hinge is that of the Seven against Thebes, into which he was unwillingly driven by the treachery of his wife, Eriphyle (Odyssey, xi. 326), a sister of Adrastus, who then ruled in Sicyon, and by whom the enterprise was planned to restore Polynices to the throne of Thebes. As prince of Argos, Amphiaraus was in a position to assist greatly; but when called upon by Adrastus to take a part, he declined, on the ground that the cause was unholy, and would end fatally. His marriage with Eriphyle, however, had not only been meant to heal previous quarrels between him and Adrastus, but was to be a bond of peace for the future in this way, that she should always arbitrate between them. To secure her favour now, Polynices gave her the fatal necklace which Cadmus had once given to Harmonia, and, though warned of the consequences, Eriphyle accepted it and decided against her husband. Knowing that he would never return, Amphiaraus enjoined his son Alcmaeon, then a boy, to avenge his death upon his mother ; and to his children generally he gave wise counsel. As he stepped into his chariot to depart he turned with a look of anger towards his wife, a scene which was represented on the chest of Cypselus. The assault of Thebes was disastrous to the Seven ; and Amphiaraus, pursued by Periclymenus, would have fallen by his spear had not Jupiter, at a critical moment, struck the earth with a thunderbolt, and caused it to open and swallow him with his horses, Thoas and Dias, his chariot, and his charioteer, Baton. Jupiter and Apollo, it is said in the Odyssey (xv. 245), loved Amphiaraus dearly; yet he did not reach an old age, but fell at Thebes, through the gift accepted by his wife. After death he continued, as a deified hero, to exercise his prophetic power by giving oracles on the spot where he had sunk into the earth. In earlier times this was believed to have happened at Harma, on the way from Thebes to Potniae, and it was there that the oracle of Amphiaraus was which Croesus and Mar- donius consulted (Herodotus, i. 49, 52; viii. 134). After wards this oracle yielded to that in the neighbourhood of Oropus, where was also a sanctuary to Amphiaraus (Jupiter Amphiaraus, as he was styled), with athletic and