Page:The New International Encyclopædia 1st ed. v. 01.djvu/554

AMLWCH. formed by excavation out of the solid slate rock, at the expense of the mining companies, capable of receiving vessels of 600 tons. Pop., 1891, 5400; 1901, 5300.

AM'MAN. See.

AM'MAN, (1669-1724). A Swiss physician, and one of the earliest writers on the instruction of the deaf and dumb. In his work, Surdus Loquens (1692), he describes the process employed by him in teaching, which was principally by fixing the attention of the pupils on the motions of his lips and larynx while he spoke, and inducing them to imitate him until they could utter distinct words. He practiced in Holland.

AM'MAN,, or (1539-91). An engraver and designer of great productiveness, many of whose works are in the Berlin collection of engravings. He was born in Zürich and after 1560 lived at Nuremberg. He began a series of copperplate portraits of the kings of France (published 1576), and made many woodcuts for the Bible. His drawing is correct and spirited, and his costumes are minutely accurate.

AMMANATI, am'ma-na'te, Bartolommeo (1511-92). An Italian architect and sculptor, born at Settignano; one of the foremost artists of the Late Renaissance or Baroceo, at first a pupil of Baccio Bandinelli, and afterward of Sansovino, at Venice, whom he assisted in connection with the Library of St. Mark. On his return to Florence he came under the influence of Michelangelo's Medici Chapel sculptures. He went to Rome and collaborated with Vignola at the Villa of Pope Julius, under Pope Paul III. He returned to Florence in 1557, became architect of Cosmo de' Medici, and devot- ed himself thenceforth to the beautifying of his native city. His Santa Trinita Bridge, several fountains and small private palaces (Pucci, Giugni), are successful; but his great courts of the Pitti Palace and Santo Spirito are in bad taste. He afterward redeemed himself in the simpler court of the Collegio Romano at Rome (1582), and in the Ruspoli Palace (1586).

AM'MEN, (1820-98). An American naval officer. He was born in Brown Co., Ohio, entered the naval service as midshipman in 1836, and by successive promotions rose to the rank of rear-admiral in 1877. In 1861-62, and again in 1863-64, he served in Admiral Dupont's blockading squadron, and as commander of the gunboat Seneca participated in the reduction of Port Royal (November 7, 1861), and took command of the forts after their surrender. He commanded the monitor Patapsco before Fort Macallister (March 3, 1863). and before Fort Sumter (April 7, 1863); and in the two attacks on Fort Fisher (December, 1864, and January, 1865), was in command of the Mohican. He served as chief of the Bureau of Yards and Docks from 1869 to 1871, and of the Bureau of Navigation from 1871 to 1878, when he retired to private life. He designed the "Ammen life raft" and the ram Katahdin, and wrote The American Inter-Oceanic Ship Canal Question (1880); The Atlantic Coast (1883), a discriminating account, from the standpoint of a naval specialist, of the operations of the Federal navy along the Atlantic coast during the Civil War; Country Homes and Their Improvement; and The Old Navy and the New (1891).

AMMENHAUSEN, am'mcn-hou'zen, Kon- rad von. A German poet of the fourteenth century. He traveled extensively, became a monk at Stein, and wrote a long, rhymed poem on the game of chess. For much of his material he drew upon the Latin work of Jacobus de Cessolis. The poem is valuable for the anec- dotes of the Middle Ages which it preserves, and still more for extended references to con- temporaneous history.

AMMERGAU (iim'mer-gou) MYSTERY. See.

AM'METER, or AMPERE'METER (ampere + Gk. μέτρον, metron, measure). An instrument which is used to measure the intensity of an electric current, and which indicates this quantity directly in amperes (q.v.). Ammeters are constructed in numerous forms, which are based for the most part on the galvanometer (q.v.), on the intensity of attraction for soft iron exerted by a hollow coil of wire carrying a current, or on the electro-dynamometer. As the galvanometer is used to detect and measure minute currents, so the ammeter is employed in testing and engineering to indicate large currents, and to enable an observer to read directly in amperes the current flowing at any instant in a circuit. The best form of ammeter is the Weston instrument, made in the United States, and used all over the world. It consists of a voltmeter (q.v.) or portable galvanometer, whose movable coil is connected in parallel with a low resistance formed by one or more copper wires. As the current in a circuit depends upon the fall in potential across a constant resistance (in this case the copper wire), the operation of the instrument will readily be seen. Numerous other forms of ammeters are constructed, the simplest of which consist of a coil of wire through which the current passes, inclosing a soft iron core suspended by a spring. The amount that this core is attracted is indicated by a pointer on a scale, which can be made regular by constructing the core of suitable shape. In other ammeters a magnetic needle is placed between the poles of a strong permanent magnet, and is surrounded by coils through which the current passes. This current in passing deflects the needle by an amount depending upon its intensity. The dynamometer or some modification of it, is often used to measure alternating currents, and consists of two coils, one of which is free to revolve against the action of a spring. When the current passes through the two coils, which are normally at right angles, there is a tendency for the movable coil to take a position parallel to the other, and the amount of motion depends upon the intensity of the current.

AM'MIA'NUS MAR'CELLI'NUS. The last Latin historian of the Roman Empire. He flourished in the closing years of the fourth century, and wrote a history of Rome from the accession of Nerva (96) to the death of Valens (378), designed as a continuation of the histories of Tacitus. The work when complete was in thirty-one books, of which only eighteen (14-31) are extant, covering the last twenty-five years of contemporaneous history (353-378). Ammianus Marcellinus was himself a Greek, born at Antioch; but he had served for years in the army, and had risen to rank in the Eastern and Gothic campaigns before he settled down