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MAGNAN a grand officer of the legion of honor, and was promoted to command the division of Stras- burg. In July, 1849, he was elected to the legislative assembly, but took little part in the sittings, being prevented by military duty. He was appointed to the command of the army of Paris, July 15, 1851, aided Louis Napoleon in organizing the coup d'etat, and fought under Gen. Saint- Arnaud on Dec. 2, 3, and 4. He was promoted to the rank of marshal, in 1852 was made a senator, and in 1854 grand hunts- man. On the outbreak of the Italian war in 1859, he took command of the army of Paris. MAGNAN, Valentin, a French physician, born in Perpignan, March 16, 1835. He completed his studies in Paris in 1863, and won in 1865 the Civrieux academical prize for his fitude clinique sur la paralyse generale (new ed., 1873). In 1867 he became physician to the asylum of Ste. Anne, connected with the cen- tral administration of lunatics, and here he acquired celebrity by his lectures on the fatal effects of alcohol and absinthe. An additional Civrieux prize was awarded to him in 1873 for his treatise Des diverses formes du delire alco- olique et de leur traitement. His fitude ex- perimentale et clinique sur V alcoolisme (1871), and contributions to medical and other jour- nals, have exerted much influence in promo- ting the cause of temperance in France. MAGNENTIPS, Flavins Popilins, Koman emperor of the West, died in August, 353. He is said to have been of a German family of Gaul, and taken captive by Constantius Chlorus or Con- stantine. Under the latter he rose to the rank of count. Having been intrusted by Constans with the command of the Jovian and Herculean legions, which had been substituted for the ancient prastorian guards at the remodelling of the empire by Diocletian, he availed himself of his office to plot the emperor's overthrow. On Jan. 18, 350, presenting himself in imperial robes at a great banquet given by one of the conspirators at Autun, he was immediately sa- luted with the title of Augustus; and assas- sins sent for the purpose having despatched Constans, Magnentius was acknowledged as emperor by all the western provinces except Illyria. Constantius, on hearing of his broth- er's murder, hastened from the confines of Persia and defeated Magnentius in a most san- guinary battle at Mursa (Eszek) on the Drave in 351, and in the passes of the Cottian Alps in 353. These disasters led to the defection of all the countries that had recognized the usurper, who thereupon committed suicide. MAGNESIA. I. The most easterly division of ancient Thessaly, Greece, .a narrow and mountainous strip of land, containing among others Mts. Ossa and Pelion, and bounded IS. by the lower course of the Peneus, on the con- fines of the Macedonian district of Pieria, E. and S. E. by the JSgean, S. W. by the Paga- saean gulf, and W. by the great Thessalian plain. II. The name of two ancient cities of Asia Minor. One, a town of Lydia (now Ma- MAGNESIA 851 nissa), was situated on the Hermus, at the foot of Mt. Sipylus, and celebrated by the great victory of the Romans over Antiochus the Great of Syria (190 B. C.), which made the conquerors masters of a part of Asia Minor. The other, in Caria, was situated on the river Lethseus in the valley of the Meander, and had a celebrated temple of Diana, the ruins of which are still visible. MAGNESIA, the only known oxide of the met- al magnesium, one of the alkaline earths, the compound character of which was discovered by Davy. It consists of 60 per cent, of mag- nesium and 40 of oxygen. Like lime, it is found in nature combined with carbonic acid, which may be expelled by calcination at a red heat; the native oxide is called periclase. It is a fine, light, white powder, having neither taste nor smell, almost insoluble in boiling water but less so in cold, of specific gravity 2-3, and known as calcined magnesia. It was regarded as infusible until melted by Dr. Hare with his compound blowpipe. Its properties are alka- line, and it neutralizes all acids. Magnesia ex- ists in the magnesian limestones (see DOLO- MITE), and forms the mineral species magnesite. From these it may be obtained, but the sources that chiefly furnish it are the sulphate of mag- nesia (see EPSOM SALT) of mineral springs, or this salt mixed with chloride of magnesium sup- plied by the bittern of salt works. Magnesia alba is prepared by mixing together dilute so- lutions of sulphate of magnesia and carbonate of soda, with or without heating. An inter- change of acids and bases takes place, and an insoluble carbonate of magnesia is precipitated, which may be washed with hot water, collected, and dried. For heavy magnesia a cold saturated solution of carbonate of soda is added to an equal volume of boiling saturated solution of sulphate of magnesia, and three volumes of water. The mixture is boiled till effervescence has ceased, and then more boiling water is added, the whole being continually stirred. This variety is granular, while the light is more or less intermixed with prismatic crys- tals. The light cubes of magnesia are prepar- ed by removing the precipitate, after it has drained for one or two days in linen strainers, to cubical moulds open at the bottom, and standing in a warm room upon a table of plas- ter or porous stone, which absorbs the water. After a time the moulds are turned over, so as to present another side to the absorbent sur- face. Carbonate of magnesia resembles ^ the calcined in its appearance and qualities ; it is somewhat more soluble in cold than in hot water, but still requires to dissolve it 9,000 parts of the latter and 2,493 of the former. It contains some water in its composition, but the proportions of its ingredients vary with the methods of its preparation. The hypochlo- ride of magnesia has bleaching properties equal to those of chloride of lime. Several salts of magnesia are used in medicine, the most important being the oxide, carbonate, sulphate,