ASTR^EA ASTROLOGY 1STRSA (Gr. aarpala, starry), a genus of radiate animals of the polyp family, which at- tach themselves to marine bodies, and are often found collected together into a globular or hemispherical mass, known as one of the forms of coral. The upper surface of these masses is entirely covered with little cavities of stellar form, each one of which is the recep- tacle of a polyp, and in the centre is its mouth, from which radiate its numerous tentacula or arms. These cavities are either in close con- tact or separated by intervening spaces; and this feature is made the basis for dividing the genus into two sections, the first of which is represented by the common East India species, A.favosa, and the other by the A. rotulosa of the West Indies. ASTRAKHAN, or A t radian. I. A government of S. E. Russia, on the N. W. shore of the Cas- pian sea; area, 85,010 sq. m. ; pop. in 1867, 573,954, including 134,000 Kirghizes. The Volga, flowing from N. W. to S. E., divides it into two arid steppes of nearly equal size, with a few fertile tracts, pasture lands, and grain fields along the banks of the river. The whole coun- try seems to have once been covered by the Caspian, and the soil abounds with saline in- gredients. Salt lakes and marshes are abun- dant. Rock salt and gypsum are found. There are few trees. The climate is extremely hot in summer and cold in winter, and unwhole- some to strangers. Cattle, goats, and a poor breed of horses are raised, and the goat skins are used for the manufacture of morocco leath- er. The most valuable industry is fishing, the fisheries of the Volga being extraordinarily productive. The principal rivers besides the Volga are the Akhtnba, Sarpa, and Kuma. The most important towns, besides the capital, are Krasnoi-Yar, Tchernoi-Yar, and Tzarev. The population is composed of Kalmucks, Kir- ghizes, Tartars these three being nomadic tribes and Russians, Armenians, Persians, Hindoos, and Germans. Astrakhan was an- ciently a khanate of the Golden Horde of Tar- tars, and embraced, besides Astrakhan proper, Saratov, Orenburg, and the Caucasus. It was annexed to Russia by the czar Ivan the Ter- rible in 1554. II. The capital of the preced- ing government, situated on an island formed by one of the branches of the Volga, about 20 m. from the sea; pop. in 1867, 47,839. The houses are partly of brick, partly of wood, and the streets are crooked, unpaved, and dirty. The population is composed of all nations of Europe and Asia, and of nearly all creeds. There are mosques for the Mohammedans and sanctuaries for the Hindoos, as well as Chris- tian churches. The city has a naval academy, several public schools, a Greek theological sem- inary, Greek and Armenian archbishops, and a printing office for the Kalmuck language. About 100 small manufacturing establishments produce cashmere shawls, silk and cotton fab- rics, furs, dyes, powder, and salt. The salt works are very extensive, and its fisheries in the Volga and Caspian are, next to those of Newfoundland, the most important in the world. Astrakhan is an entrepot of the Rus- sian oriental trade, and the raw produce from the remoter regions, consisting principally of hides, sheepskins, and grease, is brought there. The Volga is its great channel of inland nnvi- gation, and in 1863 its imports were valued at $997,976, and its exports at $215,448. The trade of the Caspian, with Astrabad and other Persian ports on the S. and Tartary on the E., belongs almost wholly to Astrakhan and Baku. The harbor of Astrakhan, however, is much obstructed by sand. ASTRINGENTS (Lat. aetringcre, to bind), agents which have the power to contract the animal tissues, diminish the amount of their fluids, and increase their density. They seem to act partly by a direct coagulation of albu- minous and gelatinous structures, and partly by diminishing the size of the blood vessels and consequently the amount of blood. An exam- ple of the first mode is seen in the formation of leather by tanning, which, however, is a degree of action far beyond what can take place in the living body. Astringents diminish both the absorbing and secreting functions of mucous membranes, and coagulate the secre- tions already formed. They excite a peculiar feeling of dryness and puckering in the mouth. They are used to check bleeding and excessive discharges from mucous membranes, to pro- mote the healing of ulcerated surfaces, and to restore lax and flabby tissues to their normal firmness. Some of them are absorbed, and, after passing through the blood, are excreted by the kidneys. The vegetable astringents, nutgalls, oak and hemlock bark, kino, catechu, rhatany, logwood, crane's-bill, ui-a urti, Tvin- tergreen, and a large number of others, con- tain more or less of the different forms of tan- nic and gallic acids. The chief mineral astrin- gents are acetate of lead, the different alums, persalts of iron, nitrate of silver, and the sul- phates of copper and zinc. Some astringents, as tannic acid, alum, and lead, find a useful ap- plication in the arts of dyeing and tanning. ASTROLOGY (Gr. aar/mv, star or constellation, and /Wyof, discourse), a system of rules for dis- covering future events by studying the positions of the heavenly bodies, which was received for ages as a science, but lias now lost all credit in civilized nations. It was divided into two kinds : judicial; by which the fate and acts of men and nations might be foreknown ; and natural, by which the events of brute and in- animate nature, such as the changes of the weather, &c., might be predicted. The etymo- logical meaning of the word astrology is almost the same as that of astronomy ; and there was no clear distinction made between the two branches until the time of Galileo. Previously, most students of the movements of the heav- enly bodies had been more or less astrologers. The invention of the telescope and the gen- eral establishment of the Copernican system
