dense Russian population, the centre of which is Kuznetsk, on the Tom.
Geology.—Geologically the Altai mountains consist of two distinct elements which differ considerably from each other in composition and structure. The Russian Altai is composed mainly of mica and chlorite schists and slates, together with beds of limestone, and in the higher horizons Devonian and Carboniferous fossils occur in many places. There is no axial zone of gneiss, but intrusions of granite and other plutonic rocks occur, and the famous ore deposits are found chiefly near the contact of these intrusions with the schists. The strata are thrown into folds which run in the direction of the mountain ridges, forming a curve with the convexity facing the south-east. The Mongolian or Great Altai, on the other hand, consists mainly of gneiss and Archaean rocks. The strike of the rocks is independent of the direction of the chain, and the chain is bounded by faults. It is, in fact, a horst and not a zone of folding.
Flora.—The Flora of the Altai, explored chiefly by Karl F. von Ledebour (1785-1851), is rich and very beautiful. Up to a level of 1000 ft. on the northern and 2000 ft. on the southern slopes, plant life belongs to the European flora, which extends into Siberia as far as the Yenisei. The steppe flora penetrates into the mountains, ascending some 1100-1200 ft., and in sheltered valleys even up to 5500 ft., when it of course comes into contact with the purely alpine flora. Tree vegetation, which reaches up as high as 6500 and 8150 ft., the latter limit on the north and west, consists of magnificent forests of birch, poplar, aspen, and Coniferae, such as Pinus cembra, Abies sibirica, Larix sibirica, Picea obovata, and so on, though the fir is not found above 2500 ft., while the meadows are abundantly clothed with brightly coloured, typical assortments of herbaceous plants. The alpine meadows, which have many species in common with the European Alps, have also a number of their own peculiar Altaian species.
Mineral wealth.—The Altai proper is rich in silver, copper, lead and zinc ores, while in the Kuznetsk Ala-tau, gold, iron and coal are the chief mineral resources. The Kuznetsk Ala-tau mines are only now beginning to be explored, while the copper, and perhaps also the silver, ores of the Altai proper were worked by the mysterious prehistoric race of the Chudes at a time when the use of iron was not yet known. Russians began to mine in 1727 at Kolyvan, and in 1739 at Barnaul. Most of the Altai region, covering an area of some 170,000 sq. m. and including the Kuznetsk district, has since 1746 formed a domain of the imperial family under the name of the Altai Mining District. The ores of the Altai proper nearly always appear in irregular veins, containing silver, lead, copper and gold—sometimes all together,—and they are, or were, worked chiefly by Zmeinogorsk (or Zmeiev), Zyryanovsk, Ust-Kamenogorsk and Riddersk (abandoned in 1861). They offer, however, great difficulties, especially on account of their continually varying productivity and temperature of fusion. The beautiful varieties of porphyry—green, red, striped—which are obtained, often in big monoliths, near Kolyvan, are cut at the imperial stone-cutting factory into vases and other ornaments, familiar in the art galleries and palaces of Europe. Aquamarines of mediocre quality but enormous size (up to 3 in. in diameter) are found in the Korgon mine. The northern, or Salair, mining region is rich in silver ores, and the mine of this name used formerly to yield up to 93,300 oz. of silver in the year. But the chief wealth of the northern Altai is in the Kuznetsk coal-basin, also containing iron-ores, which fills up a valley between the Kuznetsk Ala-tau and the Salair range for a length of about 270 m., with a width of about 65 m. The coal is considered equal to the best coal of England and south Russia. The country is also covered with thick diluvial and alluvial deposits containing gold. However, all the mining is now on the decline.
Population.—The Russian population has rapidly increased since the fertile valleys belonging to the imperial family have been thrown open to settlement, and it has been estimated that in 1908 the population of the region (Biysk, Barnaul and Kuznetsk districts) reached about 800,000. Their chief occupations are agriculture (about 3,500,000 acres under culture), cattle-breeding, bee-keeping, mining, gathering of cedar-nuts and hunting. All this produce is exported partly to Tomsk and partly to Kobdo in Mongolia. The natives may represent a population of about 45,000. They are Altaians in the west and Telenghites or Teleuts in the east, with a few Kalmucks and Tatars. Although all are called Kalmucks by the Russians, they speak a Turkish language. Both the Telenghites and the Altaians are Shamanists in religion, but many of the former are already quite Russified. The virgin forests of the Kuznetsk Ala-tau—the Chern, or Black Forest of the Russians—are peopled by Tatars, who live in very small settlements, sometimes of the Russian type, but mostly in wooden yurts or huts of the Mongolian fashion. They can hardly keep any cattle, and lead the precarious life of forest-dwellers, living upon various wild roots when there is no grain in the spring. Hunting and fishing are resorted to, and the skins and furs are tanned.
Towns.—The capital of the Altai region is Barnaul, the centre of the mining administration and an animated commercial town; Biysk is the commercial centre; Kuznetsk, Ust-Kamenogorsk, and the mining towns of Kolyvan, Zmeinogorsk, Riddersk and Salairsk are the next largest places.
ALTAMURA, a town of Apulia, Italy, in the province of Bari, 28 m. S.S.W. of the town of that name, and 56 m. by rail via Gioia del Colle. Pop. (1901) 22,729. It possesses a fine Romanesque cathedral begun in 1232 and restored in 1330 and 1531, the portal being especially remarkable. It is one of the four Palatine churches of Apulia. The surrounding territory is fertile. The medieval walls, erected by the emperor Frederick II., rest upon the walls of an ancient city of unknown name. These early walls are of rough blocks of stone without mortar. Ancient tombs with fragments of vases have also been found, and there are cases which have been used as primitive tombs or dwellings, and a group of some fifty tumuli near Altamura.
ALTAR (Lat. altare, from altus, high; some ancient etymological guesses are recorded by St Isidore of Seville in Etymologiae xv. 4), strictly a base or pedestal used for supplication and sacrifice to gods or to deified heroes. The necessity for such sacrificial furniture has been felt in most religions, and consequently we find its use widespread among races and nations which have no mutual connexion.
Mesopotamia.—Altars are found from the earliest times in the remains of Babylonian cities; the oldest are square erections of sun-dried bricks. In Assyrian mounds limestone and alabaster are the chief material. They are of varying form; an altar shown in a relief at Khorsabad is ornamented with stepped battlements, which are the equivalent of the familiar “altar-horns” in Hebrew ritual. An altar also from Khorsabad (now in the British Museum) has a circular table and a solid base triangular on plan, with pilasters ornamented with animals' paws at the angles. A third variety, of which an 8th century B.C. example from Nimrud exists in the British Museum, is a rectangular block ornamented at the ends by cylindrical rolls. These altars are in height from 2 to 3 ft. According to Herodotus (i. 183) the great altars of Babylonia were made of gold.
Egypt.—In Egypt altars took the form of a truncated cone or of a cubical block of polished granite or of basalt, with one or more basin-like depressions in the upper surface for receiving fluid libations. These had channels whereby fluids poured into the receptacles could be drained off. The surface was plain,