the word both with “corn” and “oak-horn,” and the spelling changed accordingly.
ACORUS CALAMUS, sweet-sedge or sweet-flag, a plant of the natural order Araceae, which shares with the Cuckoo Pint (Arum) the representation in Britain of that order of Monocotyledons. The name is derived from acorus, Gr. ἄκορος, the classical name for the plant. It was the Calamus aromaticus of the medieval druggists and perhaps of the ancients, though the latter has been referred by some to the Citron grass, Andropogon Nardus. The spice “Calamus” or “Sweet-cane” of the Scriptures, one of the ingredients of the holy anointing oil of the Jews, was perhaps one of the fragrant species of Andropogon. The plant is a herbaceous perennial with a long, branched root-stock creeping through the mud, about 34 inch thick, with short joints and large brownish leaf-scars. At the ends of the branches are tufts of flat, sword-like, sweet-scented leaves 3 or 4 ft. long and about an inch wide, closely arranged in two rows as in the true Flag (Iris); the tall, flowering stems (scapes), which very much resemble the leaves, bear an apparently lateral, blunt, tapering spike of densely packed, very small flowers. A long leaf (spathe) borne immediately below the spike forms an apparent continuation of the scape, though really a lateral outgrowth from it, the spike of flowers being terminal. The plant has a wide distribution, growing in wet situations in the Himalayas, North America, Siberia and various parts of Europe, including England, and has been naturalized in Scotland and Ireland. Though regarded as a native in most counties of England at the present day, where it is now found thoroughly wild on sides of ditches, ponds and rivers, and very abundantly in some districts, it is probably not indigenous. It seems to have been spread in western and central Europe from about the end of the 16th century by means of botanic gardens. The botanist Clusius (Charles de l’Escluse or Lécluse, 1526–1609) first cultivated it at Vienna from a root received from Asia Minor in 1574, and distributed it to other botanists in central and western Europe, and it was probably introduced into England about 1596 by the herbalist Gerard. It is very readily propagated by means of its branching root-stock. It has an agreeable odour, and has been used medicinally. The starchy matter contained in its rhizome is associated with a fragrant oil, and it is used as hair-powder. Sir J. E. Smith (Eng. Flora, ii. 158, 2nd ed., 1828) mentions it as a popular remedy in Norfolk for ague. In India it is used as an insectifuge, and is administered in infantile diarrhoea. It is an ingredient in pot-pourri, is employed for flavouring beer and is chewed to clear the voice; and its volatile oil is employed by makers of snuff and aromatic vinegar. The rhizome of Acorus Calamus is sometimes adulterated with that of Iris Pseudacorus, which, however, is distinguishable by its lack of odour, astringent taste and dark colour.
ACOSTA, JOSÉ DE (1539?–1600), Spanish author, was born at Medina del Campo about the year 1539. He joined the Jesuits in 1551, and in 1571 was sent as a missionary to Peru; he acted as provincial of his order from 1576 to 1581, was appointed theological adviser to the council of Lima in 1582, and in 1583 published a catechism in Quichua and Aymara—the first book printed in Peru. Returning to Spain in 1587, and placing himself at the head of the opposition to Acquaviva, Acosta was imprisoned in 1592–1593; on his submission in 1594 he became superior of the Jesuits at Valladolid, and in 1598 rector of the Jesuit college at Salamanca, where he died on the 15th of February 1600. His treatise De natura novi orbis libri duo (Salamanca, 1588–1589) may be regarded as the preliminary draft of his celebrated Historia natural y moral de las Indias (Seville, 1590) which was speedily translated into Italian (1596), French (1597), Dutch (1598), German (1601), Latin (1602) and English (1604) The Historia is in three sections: books I. and II. deal with generalities; books III. and IV. with the physical geography and natural history of Mexico and Peru; books V., VI. and VII. with the religious and political institutions of the aborigines. Apart from his sophistical defence of Spanish colonial policy, Acosta deserves high praise as an acute and diligent observer whose numerous new and valuable data are set forth in a vivid style. Among his other publications are De procuranda salute Indorum libri sex (Salamanca, 1588), De Christo revelato libri novem (Rome, 1590), De temporibus novissimis libri quatuor (Rome, 1590), and three volumes of sermons issued respectively in 1596, 1597 and 1599.
Authorities.—José R. Carricido, El P. José de Acosta y su importancia en la literatura científica española (Madrid, 1899); C. Sommervogel, Bibliothèque de la Compagnie de Jésus, Première Partie (Brussels and Paris, 1890), vol. i., col. 31–42; and Edward Grimston’s translation of the Historia reprinted (1880) for the Hakluyt Society with introduction and notes by Sir Clements R. Markham. (J. F.-K.)
ACOSTA, URIEL (d. 1647), a Portuguese Jew of noble family, was born at Oporto towards the close of the 16th century. His father being a convert to Christianity, Uriel was brought up in the Roman Catholic faith, and strictly observed the rites of the church till the course of his inquiries led him, after much painful doubt, to abandon the religion of his youth for Judaism. Passing over to Amsterdam, he was received into the synagogue, having his name changed from Gabriel to Uriel. His wayward disposition found, however, no satisfaction in the Jewish fold. He came into conflict with the authorities of the synagogue and was excommunicated. Unlike Spinoza (who was about fifteen at the time of Acosta’s death), Acosta was not strong enough to stand alone. Wearied by his melancholy isolation, he was driven to seek a return to the Jewish communion. Having recanted his heresies, he was readmitted after an excommunication of fifteen years, but was soon excommunicated a second time. After seven years of exclusion, he once more sought admission, and, on passing through a humiliating penance, was again received. His vacillating autobiography, Exemplar Humanae Vitae, was published with a “refutation” by Limborch in 1687, and republished in 1847. In this brief work Acosta declares his opposition both to Christianity and Judaism, though he speaks with the more bitterness of the latter religion. The only authority which he admits is the lex naturae. Acosta was not an original thinker, but he stands in the direct line of the rational Deists. His history forms the subject of a tale and of a tragedy by Gutzkow. Acosta committed suicide in 1647. The significance of his career has been much exaggerated.
ACOTYLEDONES, the name given by Antoine Laurent de Jussieu in 1789 to the lowest class in his Natural System of Botany, embracing flowerless plants, such as ferns, lycopods, horse-tails, mosses, liverworts, sea-weeds, lichens and fungi. The name is derived from the absence of a seed-leaf or cotyledon. Flowering plants bear a seed containing an embryo, with usually one or two cotyledons, or seed-leaves; while in flowerless plants there is no seed and therefore no true cotyledon. The term is synonymous with Cryptogams, by which it was replaced in later systems of classification.
ACOUSTICS (from the Gr. ἀκούειν to hear), a title frequently given to the science of sound, that is, to the description and theory of the phenomena which give rise to the sensation of sound (q.v.). The term “acoustics” might, however, with advantage be reserved for the aspect of the subject more immediately connected with hearing. Thus we may speak appropriately of the acoustic quality of a room or hall, describing it as good or bad acoustically, according as speaking is heard in it easily or with difficulty. When a room has bad acoustic quality we can almost always assign the fault to large smooth surfaces on the walls, floor or ceiling, which reflect or echo the voice of the speaker so that the direct waves sent out by him at any instant are received by a hearer with the waves sent out previously and reflected at these smooth surfaces. The syllables overlap, and the hearing is confused. The acoustic quality of a room may be improved by breaking up the smooth surfaces by curtains or by arrangement of furniture. The echo is then broken up into small waves, none of which may be sufficiently distinct to interfere with the direct voice. Sometimes a sounding-board over the head of a speaker improves the hearing probably by preventing echo from a smooth wall behind him. A large bare floor is undoubtedly bad for acoustics, for when a room is filled by an audience the hearing is much improved.
