Page:The New International Encyclopædia 1st ed. v. 12.djvu/765

* MAGNESIA. 683 MAGNESIUM. its capture by the .Seljuks and later by the Ottomans, it retained its importance, and "under its modern name, JIanissa, is a flourishing town with fine' buildings, on the Smyrna-Alashehr railroad. In this region, near Mount Sipylus, Greek legend located the Kingdom of Tantalus and myth of Xiobe. There are remains of very «arly settlements on the slopes of Mount Sipylus. The second ^Magnesia was in Caria, in the valley of the Ma'ander, and called Maf/nisia on the M(e- onder (Miignrsia ad ilwandrum), to distinguish it from that near Mount Sipylus. It was 15 miles from Kphesus. This city seems also to have been a colony of Magnetes. whose wanderings through Delphi and Crete to Asia were part of the legendary history of the city. It early became wealthy and powerful, but was destro3'ed in the first half of the seventh century B.C. by the Cim- merian invaders. It was rebuilt and afterwards conquered by the Persians. King Artaxerxes assigned it to Themistocles as a residence, and after his death here, about B.C. 4G0, the inhabit- ants paid him honors as to a hero. In the neigh- borhood was a celebrated temple of Artemis Leu- cophryne, and when about B.C. 400 the old site of the city was for some reason abandoned, the inhabitants withdrew to the higher ground around the temple, where a new city was built, which, though never very prominent, was later the seat of a bishopric. The temple was Ionic, and of great beauty. Part of its sculptured frieze was brought to the Louvre by Texier. and the rest is in Constantinople. Excavations con- ducted for the Berlin Museum by Dr. Humann in 18S11-03 laid bare the temple, and also brought to light the Agora, theatre, and other buildings, as well as many inscriptions, including one con- taining the legendary account of the founding of the city. Consult: Kern, Die flriinduttps- geschichte von ilaf/ncsia am ilaiandros. (Berlin, 1894) ; id.. Die Infiehriften von Magnesia am ilwander (Berlin, 1900). MAG'NESITE (from magnesium). A mag- nesium carbonate that crystallizes in the hexagonal system, has a vitreous lustre, and is either white, light yellow, or brown in color. It is usually found in the form of irregular veins in serpentine and other magnesium rocks, being a deposition product either of the serpentine itself or of the original rock from which the serpentine is derived. It is found in many lo- calities in Moravia, Styria. Silesia, and Norway; and in the I'nited .States in ilarvland. New Jer- sey, Massachusetts, Xew York, California, and Washington. This mineral finds considerable use in the preparation of magnesian compounds, such as Epsoui salts, magnesia, and in the manu- facture of paint, paper, and fire brick; also to some extent as an adulterant for the cheaper grades of soap. A variety containing iron is called hrennnrrite, or fcroioi spar. MAGNESIUM, mag-ne'zhi-um nr -shTum (Xeo-Lat., from magnesia, from Gk. fiayvrfala [sc. ^('Sof], magnesia [sc. Iithos'. magnesian [sc. stone], magnet, from Mayvrio-la, Mafjnesia, a dis- trict in Thcssaly, where magnetic stones abound- ed). A metallic clement first isolaicd by Davy and Bussy. Certain isolated salts of magnesium were known in the seventeenth century, tlio sul- phate, for instaiuv ('Epsom salt'), having been found in the mineral waters at Epsom, England. The element is not found native, but its com- VOL. XII.— 44. pounds are widely distributed as the minerals 7nagnesile or magnesium carbonate, dolomite or magnesium-calcium carbonate, liiescrite or mag- nesium .sulphate, Icainite or magnesium sulphate with pota.ssium chloride, carnallite or magne- sium-potassium chloride, as well as numerous other minerals, containing smaller quantities. Magnesium also forms the chief constituent of mail}- silicates, such as augite, hornblende, olirine, .serpentine, tourmaline, and meerschaum. It is further found in the bones of animals and in the seeds of the cereals. The metal itself was originally obtained by heating magnesivim chloride with potassium in a platinum crucible, and wa.shing out the lesulting potassium chloride with water. It may be made by the action of metallic sodium on magnesium chloride, but it is more cheaply olitained eleetrolytically. Magnesium (symbol, Mg; atomic weight, 24.30) is a silver-white, lusti-ous, hard metal that is malleable and ductile, has a specific gravity of 1.7.5, melts at about 500° C. and boils at about 1000° C. It finds use as an illuniinant, burning readily when in the form of filings, wire, or ribbon, with a white light of great Ijrillianc.v ; thus, a burning magnesium w ire of 0.297 millimetei's thickness produces a light equal to 74 stearin candles ; hence its application for flashlights in photography, for signals, and in fireworks. Magnesium combines with various other metals to form alloys, the most interesting of which are those with potassium and sodium, which decompose water at ordinary temperatures. A silver-white alloy of aluminum and magnesium, called magnalium. has Ijeen recommended for lens mountings, spectacles, etc. When ignited in the air or oxygen it forms an oxide,_ MgO, which is a white, light, infusible, amorphovis powder that is extensively used in the manufacture of cruci- bles, cupels, fire bricks, etc. It is also vised, like lime, for the production of a light similar to the calcium light. (See DRiMMoxn Light.) The commercial article is obtained by prolonged igni- tion of the carbonate or the hydrate, both of which are derived from the saline deposits of Stassfurt, Germany. The oxide, as well as the carbonate, of magnesium finds use in medicine as a laxative and antacid. When mixed with water, the oxide gradually changes into the hydrate, which is also found native as the mineral brucite. The hydrate is used for ex- tracting sugar from molasses, forming an insolu- ble, granular, crystalline magnesium saccharate. which, when decomposed by carbon dioxide, yields pure sugar. The carbonate, which is known ciinnnercially as maijnesia alba, is pre- pared by ]>recipitating either the sulphate or the chloride with sodium carbonate. The sulphate, or Epsom salt, which occurs as the purgative princi])le of various spring waters, is obtained commercially from the minerals kieserite and ep- somite, or by decomposing dolomite with sul- phuric acid. This salt is largely used as a fer- tilizer, as a refrigerant cathartic in medicine, for dyeing with aniline colors, and for warp- sizing cotton. The rhlnridc. which occurs native with jiotassium chloride as carnallite in the Stassfurt deposits, is used by cotton spinners as a lliread luliricator. and as a source for other magnesium salts. The citr-ate. which is official in the United States Pharmacopa>ia, is used in medicine as a laxative.