MANDOLINE, is 4 PinSie41 instrument of the litte kind, but smaller, having fog strings, which are tuned in the same manner As those of the violin. The mandoline is still met with ecrAsignAllY in Italy, but bas fslteil int4 diSnse in twist other parts of Europe.
This metal was first discovered by Scheele and Oahu, al?put 1775. Its natigal compounds aye very nnynerpuS, And the metal is easily separated from thena• Manganese has A fgaIisli White eginiiri aril resembles white PaSt iii aPPAiirsinee it i4 hard, brittle, and has A fAseienlated crystalline structure ; its specific gravity is 7.0 ; it is inoderous and tasteless, but when hteathed upon, emits a smell somewhat resembling that of hydrogen gas. IV exppsure to the manganese readily tarnishes by tixidisenient., and even in a. very short time attracts sufficient oxygen to lose its metallic lustre, and falls to reddish brown powder; hence the necessity for preserving it immersed in naptha. Even at common tereperatups it slowly decomposes water ; and at a red heat the decomposition is rapidly effected, mid in both clasps hydrogen gas is evelyed, and oxide of manganese formed.
The ores pf iitanganeSe are chiellY oxides, and are very numerous, There are no fewer than five oxides of Op metals, of 'Which the protoxide gi.ves an amethystine colour to glass. Jfauganic acid has not hitherto been pbtained in a separate state ; but ratt.nganate pf potash is easily prepared. It is of a green colour,
and has long been known by the rime of mine ral chameleon., on account of the change of colour which the solution undergoes during the process. Ifyperniangailic acid has a fine red colour, and is rapidly decomposed by organic matter, as paper or linen. It ble,aches coloured matter. Manganese combines with chloride and with sulphur. A also combines with several other metals, as gold, silver, copper, tin, anal iron; with the combination takes place readily, and the iron is rendered harder, whiter, and more brittle by it; and it is stated that iron which contains manganese is best adapted for making steel. A. small quantity of iron causes manganese to obey the magnet, and renders it less oxidable. The oxides of manganese, and especially the binoxide, as containing most oxygen, are largely employed in the preparation of chlorine, for the manufacture of bleacbing powder, or chloride of lime. It is employed in glass making to correct the yellow colour which oxide of iron is apt to impart to the glass ; it is used also in making the black enamel of pottery. Sulphuret of mangariese lies also been used within a few years to give a brown eplour in oalico-printing. The kbaosicle, the sulphate, and the hydrophlorate manganese, Are All einPIPYPd in metligille,