altars, especially to consecrate imperial worship: there was one for Spain and one for Gaul (at Lyons), with an abundance of statuary and decoration, where the Spanish and Gallic councils met annually and proclaimed their political allegiance. The Altar of Peace, with its sculptured friezes, erected in honor of Augustus, at Rome, to celebrate the pacification of the world, was one of the artistic masterpieces of the Augustan reign. Of the smaller altars and tables of offerings, hundreds were erected in every city, not only in connection with the temples, but also in shrines and chapels and throughout the streets: they are among the finest pieces of Græco-Roman decoration, and are of all shapes — circular, polygonal, square or oblong. Usually each was consecrated to a single god or hero. Of course, the use to which the altar was put influenced its form: according as it was for incense or sacred fire, for libations, for fruits, flowers, or the like, or for bloody sacrifices.
In the Christian Church the altar was quite different in its suggestions. All reminiscence of heathen altars was abhorrent. The marble sarcophagi in which were buried the bodies of martyrs in the catacombs were among the earliest altars, except, indeed, plain wooden tables which developed into marble slabs with one or more legs. Only a single altar was allowed in each church — none outside — and it was always erected over the relics of a martyr. As early as the fifth century, precious metals came into use for altars. The great variety of shape in pagan times was reduced to one — moderately oblong. The altar was placed in the axis of the church, just outside the radius of the apse, or in the middle of the transept, if there was one. Beneath it was the confession (see Confession) for the relics of the saint, which afterward developed into the crypt. (See Crypt.) Above it rose a tabernacle, canopy, or ciborium. (See Ciborium.) The structure of the altar itself was rarely ornamented, though in Italy the faces were often inlaid with marbles and mosaics. Nevertheless the altar usually had a number of artistic accessories that must be mentioned to give an idea of its appearance. Altar-front was a decoration for the front and sometimes for the other sides of the altar, not merely when the structure was a slab supported on legs, but even if it were solid. It was sometimes in the shape of a rich hanging; sometimes it was a relief of gold, silver gilt, enamel, or silver. Famous mediæval altar fronts are at the Clugny Museum (from Basel), Paris; at St. Mark's, Venice; at Sant' Ambrogio, Milan; at San Jacopo, Pistoia. Altar-piece is used as a decoration placed on top of the altar, a custom that did not come into use until the Middle Ages, when the altar was made to face the people and not the apse, and when altars against the wall were multiplied. Some altar-pieces, complements to the altar-fronts, were of precious metals, as at Venice (St. Mark's), and at Pistoia (San Jacopo), but usually they were devotional pictures, preferably in the form of triptychs, or even groups of sculpture, or a sculptured tabernacle. Altar-screen is often connected with the confession and its staircase. In early churches it was surmounted by sculpture, and hardly distinguishable from an altar-rail. Consult Rohault de Fleury, La Messe (Paris, 1883).
ALTAROCHE, al'ta'rAsh',
Marie Michel, (1811-84). A French playwright and journalist, born at Issoire. From 1834 to 1848 he was editor-in-chief of Charivari, the influence of which was increased by his political satires and his general wit and acumen. He was elected to the Assembly in 1848 but retired the following year, and from that time was successively manager of the Odéon, Folies Nouvelles, and other theatrical enterprises. He wrote Chansons et vers politiques 1835). Contes démocratiques (1837), Aventures de Victor Augerol (1838), and the following plays: Lestocq ou le retour de Sibérie (1836), and Le Corrégidor de Pampelune (1843).
ALTAZ'IMUTH (altitude + azimuth; see Azimuth). An astronomical instrument, used for determining the position on the sky of stars or other heavenly bodies by measuring their altitude and azimuth. (The altitude of a star is its angular distance above the horizon, measured on a great vertical circle of the sky, perpendicular to the horizon and passing through the star and the zenith, or point directly overhead. The azimuth of a star is the angular distance, measured on the horizon, from the south point of the latter to the foot of the vertical circle upon which the altitude is measured.) The altazimuth instrument has two brass circles, one with its plane horizontal, the other with its plane vertical, and a telescope is attached to the circles. When this is directed so that a star appears at the intersection of a pair of crossed threads fixed in the field of view, it is possible to read the star's altitude and azimuth from the graduations engraved on the two circles. Being of considerable complexity, the instrument does not give results of a precision quite equal to those obtained with the meridian circle; and for this reason it is employed chiefly in its portable form when observations must be made at temporary observatories. such as eclipse expedition stations. It is in use, however, at Greenwich, for observing the moon on nights when it is not possible to observe that body in the meridian.
ALTDORF, alt'dOrf,
or ALTORF. The capital of the Swiss canton of Uri, situated in a sheltered spot at the base of the Grunberg, about 2 miles east of the lake of Lucerne (Map: Switzerland. C 2). It lies 1475 feet above sea level, and is a well built town, having several open places, a church, a nunnery, and the oldest Capuchin monastery in Switzerland, built in 1581. The town is connected with the Tell legend — for Tell is said to have lived near by — and Tell dramas are still played here. The spot where his son stood to be shot at is marked by a bronze statue of father and child, by Kissling, erected in 1895. Southeast about 1½ miles is the entrance to the Schächenthal. Pop., 3000.
ALTDORFER, alt'dOr-fer,
Albrecht (? 1480-1535). A Bavarian painter and engraver on copper and wood. The exact date and place of his birth are unknown, though the latter was probably near Landshut: but most of his life was passed at Regensburg, where he practically founded a school, and where he died Feb. 13, 1538. He was influenced to some extent by Dürer, but is of independent importance. His pictures are marked especially by romantic imagination, his landscapes, which constitute the most important part of his work as a painter, being more the creation of his own fancy than faithful transcripts of nature. But while his drawing is frequently disappointing, his coloring is rich and strong. One of his best-known works, the "Victory of Alexander at Arbela" (1529), so
