A´mos, one of the minor prophets; flourished under the Kings Uzziah of Judah and Jeroboam II of Israel (810 to 784 B.C. by the common chronology). Though engaged in the occupations of a peasant he must have had a considerable amount of culture, and his book of prophecies has high literary merits. It contains denunciations of Israel and the surrounding nations, with promises of the Messiah.
Amoy´, an important Chinese trading port, on a small island off the south-east coast opposite Formosa; has a safe and commodious harbour, and its merchants are among the wealthiest and most enterprising in China; one of the five ports opened to foreign commerce by the treaty of Nanking in 1842. The privilege was confirmed and extended by the treaty of Tien-tsin in 1858, and the port is now open to all countries. Pop. 114,000.
Ampel´idæ. See Chatterers.
Ampère (a˙n˙-pār), André-Marie, a celebrated French mathematician and philosopher, founder of the science of electro-dynamics, born at Lyons in 1775, died at Marseilles in 1836; professor of
mathematical analysis at the Polytechnic School, Paris, and of physics at the College of France. What is known as Ampère's Theory is that magnetism consists in the existence of electric currents circulating round the particles of magnetic bodies, being in different directions round different particles when the bodies are unmagnetized, but all in the same direction when they are magnetized.
Ampère, Jean-Jacques-Joseph-Antoine, historian and professor of French literature in the College of France; the only son of André-Marie Ampère; born at Lyons 1800, died 1864; chief works: Histoire Littéraire de la France avant le 12e siècle (1839); Introduction à l'Histoire de la Littérature française au moyen âge (1841); Littérature, Voyages et Poésies (1833); La Grèce, Rome et Dante, Études Littéraires d'après Nature; l'Histoire romaine à Rome (4 vols. 8vo, 1856-64); Promenades en Amérique (1855); César, Scènes historiques (1859), full of hostile allusions to the French Empire.
Ampere (am´pār), in electricity, the unit employed in measuring the strength or intensity of an electric current, being equivalent to the current produced by the electro-motive force of one volt in a wire having the resistance of one ohm. The name (cf. Farad, Coulomb, Watt, &c.) is derived from that of the well-known physicist, Ampère. An ampere-meter or ammeter is an instrument by which the strength of an electric current is given in amperes.
Amphib´ia, a class of vertebrate animals, which in their early life breathe by gills or branchiæ, and afterwards partly or entirely by lungs. The Frog, breathing in its tadpole state by gills and afterwards throwing off these organs and breathing entirely by lungs in its adult state, is an example of the latter phase of amphibian existence. The Proteus of the underground caves of Central Europe exemplifies forms in which the gills of early life are retained throughout life, and in which lungs are developed in addition to the gills. A second character of this group consists in the presence of two occipital 'condyles', or processes by means of which the skull articulates with the spine or vertebral column; Reptiles possessing one condyle only. The class is divided into four orders: the Ophiomorpha (or serpentiform), represented by the Blindworms, in which limbs are wanting and the body is snake-like; the Urodela or 'Tailed' Amphibians, including the Newts, Proteus, Siren, &c.; the Anoura, or Tailless Amphibia, represented by the Frogs and Toads; and the Labyrinthodontia, which includes the extinct forms known as Labyrinthodons. The term Amphibia was originally employed by Linnæus in his Systema Naturæ, and adopted by Cuvier in his Tableau Elémentaire. See Batrachia.
Amphibol´ogy, in logic, an equivocal phrase or sentence, not from the double sense of any of the words, but from its admitting a double construction, as 'The duke yet lives that Henry shall depose'.
Amphic´tyonic League (or Council), in ancient Greece, a confederation of tribes for the protection of religious worship, but which also discussed questions of international law, and matters affecting their political union. The most important was that of the twelve northern tribes which met alternately at Delphi and Thermopylæ. The tribes sent two deputies each, who assembled with great solemnity; composed the public dissensions, and the quarrels of individual cities, by force or persuasion; punished civil and criminal offences, and particularly transgressions of the law of nations, and violations of the temple of Delphi. Its calling on the States to punish the Phocians for plundering Delphi caused the Sacred Wars, 595-586, 448-447, 357-346 B.C.