BARIUM (sym. Ba, eq. 68.5, in new system 137) is the metal present in heavy spar (sulphate of baryta) and baryta. It was regarded as a white metal, until the researches of Dr. Matthiesen demonstrated that it possesses a yellow color. As yet, the metal B. has not been obtained in mass, but only as a powder. It decomposes water readily at ordinary temperatures, and exposed to the air, quickly combines with oxygen, forming the oxide of B. (I3a0), or BARYTA. The latter substance is an earth resembling ordinary caustic lime, and may otherwise be prepared by adding finely divided black oxide of copper (CuO) to a solution of sulphuret of B. (BaS), when the sulphuret of copper (CuS) is thrown down, and the baryta (Ba0) is left in solution. On evaporation the water of solution passes off as steam, and leaves the solid earthy-looking substance, baryta. A
third mode of preparing baryta is to heat strongly the nitrate of baryta (Ba0N0s), when the nitric acid (NO,) Hies off, and leaves the baryta (BaO). The sulphuret of B. (BaS) is obtained when the sulphate of baryta in powder is mixed with finely-pul verized coal, and the whole being placed in a crucible, is raised to a red heat in a fur nace. The result is, that 4 atoms of the carbon (C) of the coal carry off the 4 atoms of oxygen in the sulphate of baryta as carbonic oxide (CO), whilst the f3. united solely with sulphur is left behind as the sulphuret of B. (BaS). The chloride of B. is prepared by adding h. drochloric acid (HC1) to a solution of the sulphuret of B. (BaS), when hydro sulphuric acid (HS) escapes, and chloride of B. remains behind, and on evaporation of the liquid, is obtained in crystals.