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252 VANADIUM buildings excepting the palace of the local au- thorities, the mosques, and Armenian churches. A third chapel and a school were opened in 1874 by the American missionaries. Coarse cotton cloth is made and exported, and there are salt refineries. A rocky hill with a ruined citadel extends over one mile ; inside the cita- del are vast caves with cuneiform inscrip- tions and other relics referred to the days of Semiramis, who, according to tradition, laid out the city on a magnificent scale and re- sided there in summer; hence the Armenian name of Shamiramagerd, city of Semiramis. It took its present name from the Armenian king Van (371-351 B. 0.), who embellished and extended the place. Under the real or nominal rule of the Macedonian and Syrian Greeks it became known as Iban. It was afterward the seat of the Armenian dynasty of the ArsacidiB, which, with intervals of Ro- man domination, reigned till A. D. 428, when the country was subjugated by the Persians. At the close of the 10th century Van flour- ished once more as the capital of the third Ar- menian kingdom of Vashburagan. The inva- sion of the Seljuk Turks in the llth century ushered in a long series of calamities, and the extinction of the Armenian kingdom. The sanjak of Van comprises a large population of Armenians, Kurds, and Turkomans. II. A celebrated salt lake, the largest in Armenia, about 1,400 sq. m. in extent, and 5,400 ft. (ac- cording to Rawlinson) above the sea level. It is a triangular basin extending N. E. to S. W. over 80 m. between Amis and Tadvan ; great- est width, between Akhlat and Van, about 50 m. It is surrounded by high mountains, reach- ing in parts the level of perpetual snow, al- ternating with beautiful plains. The waters are of the deepest blue ; the luxuriant vegeta- tion along its banks is unsurpassed in that part of Asia. It has no outlet, but is less impreg- nated with salt than Lake Urumiah, receives several streams, and contains islets. Among the interesting towns on the lake shore is Akhlat, once the residence of Armenian kings, with a vast population. VANADIUM, a metal, first recognized as dis- tinct in 1801 by Del Rio, who found it in the brown lead ore (now known as vanadinite) of Zimapan in Mexico, and called it erythronium. But it was generally considered by chemists to be chromium, an opinion afterward adopted by Del Rio himself. In 1830 Sefstrom found the iron made from the magnetic ore of Ta- berg in Sweden, as well as the cinder produced in its conversion, to contain a peculiar metal, which he called vanadium, from Vanadis, one of the names of the Scandinavian goddess Freyja ; and the Zimapan lead ore was after- ward found by Wohler to contain the same metal. It has also been discovered in the iron slag of Staffordshire, and recently by Roscoe in larger quantity in the copper-bearing beds at Alderley Edge and Mottram St. Andrews, Cheshire, by Dr. Bolton in pitchblende, by Dr. Hayes in many rocks, and by Bottger in pea iron ores. The metal is obtained by prolonged ignition of the dichloride in a stream of pure dry hydrogen gas. It is a grayish white pow- der, which has the appearance under the mi- croscope of a silver-white crystalline mass. It does not tarnish in the air, burns with bril- liant scintillations when thrown into a flame, burns vividly when quickly heated in oxygen, forming a pentoxide, and takes fire in a cur- rent of chlorine gas, forming a tetrachloride. It is insoluble in hydrochloric acid. It has until recently been regarded as a hexad me- tal, analogous to tungsten ; but Roscoe has shown, by a comparison based upon the com- position of the oxides and oxychlorides, and upon the isomorphism of the vanadates with phosphates, that it is a pentad, belonging to the arsenic and phosphorus group. Vanadium forms five oxides: V a O, V a O a , V a O,, V,O 4 , and V a O ; compounds analogous to the oxides of nitrogen, V a O being called vanadic anhy- dride, and sometimes pentoxide of vanadium. The monoxide, V a O, is a brown substance formed by prolonged exposure of the metal to the air at ordinary temperatures, or more quickly at a dull red heat. The dioxide, V a O a , is produced by continued heating of the mon- oxide. The trioxide, V a O, is formed by ig- niting the pentoxide, V a O, in hydrogen gas, or in a crucible lined with charcoal. When exposed to warm air it absorbs oxygen, glows with a dull red light, and passes again into pentoxide. Vanadious oxide or anhydride, or vanadium tetroxide, V a C>4, is formed by fur- ther oxidation of the dioxide or trioxide, or by partial reduction of the pentoxide. It forms with acjds vanadious salts, which have a bright blue color. Vanadium pentoxide, or vanadic anhydride, may be prepared from the native lead vanadate. The mineral is dissolved in nitric acid, and the lead and arsenic precipitated by sulphuretted hydrogen, which also reduces the vanadium pentoxide to tetroxide. The blue filtered solution is then evaporated to dryness, which reconverts the tetroxide to pentoxide. It is then digested in aqua ammo- nia, which dissolves the pentoxide. A lump of sal ammoniac (chloride of ammonium) is put into the solution, and as the salt dissolves ammonium vanadate is precipitated, being only very slightly soluble in a saturated solution of the chloride of ammonium. A temperature below redness expels the ammonium. It is a reddish yellow powder, which dissolves in 1,000 parts of water, forming a light yellow solution. With stronger acids it forms vana- dic salts, but it unites with bases more readily than with acids, forming salts called vanadates of various constitution, as orthovanadates, hav- ing the general formula (3MO),V a O ; pyro- vanadates, (3MO),V a O; metavanadates, MO,- VnOs, analogous to metaphosphates ; divana- dates, MO,2V a O s ; and tri vanadates, MO,3V a O. In the United States the principal localities of vanadium minerals are at the Wheatley mine,