71. Sulphate of lime may be detected by evaporating the water till a deposit be formed. If this be soluble in a large quantity of water, and the solution give a preci pitate with baryta, not soluble in nitric acid, and also with oxalic acid, then it is sulphate of lime.
72. Sulphate of magnesia may be procured by the addition of hydro-sulphuret of strontia, which, if there be no free acid or sulphate of alumina present, gives a precipitate only with sulphate of magnesia. If sulphate of lime be present, a precipitate will be formed, but not for twenty-four hours after the addition of the hydro sulphuret.
73. Sulphate of iron. When iron is in union with sulphuric acid, it is known by the tests of this metal de tecting it in the water after it has been boiled. (53.) 74. Alienate of soda. Precipitate the sulphates by alcohol and nitrate of baryta. After filtration, decom pose the nitrates and muriates by sulphuric acid, and boil the fluid. Again add alcohol and baryta, to pre cipitate the sulphates formed. • The fluid then contains only alkaline nitrates and muriates. If the last be pre sent, they must be decomposed by the addition of acetate of silver, by which acetates of the alkalies will be form ed. These may be known by the methods recommended. (46, 47.) 75. Muriate of lime. Deprive the water of sul phates, by evaporation, and the addition of alcohol and nitrate of baryta ; after filtration evaporate to dry ness, and digest the residue in alcohol. Evaporate the solution, and subject the residue to the action of water. If the solution afford precipitates with oxalic acid, and with acetate of silver, then it contains muriatic acid and lime. But these may not be in union with each other, as the solution may contain magnesia or alu mina. To ascertain if this be the case, add ammo nia ; if a precipitate fall, it contains magnesia. If the fluid give a precipitate on the addition of carbonate of lime, then it contains alumina, either of which may per haps be in union with the muriatic acid. If neither of these earths be present, then the fluid contains muriatc of lime. Suppose one or both present, to find out if the acid be in union with the lime, precipitate the earth by oxalic acid, filter, and subject the fluid to distillation, collecting the product in a cool receiver containing a little water. If this give a precipitate with nitrate of
silver, then it contains muriatic acid, which was set free from the lime by the addition of the oxalic acid : or the solution may be evaporated to dryness, and exposed to a red heat for an hour ; if it contain muriate of lime and magnesia in union with nitric acid, the latter salt will be decomposed. On exposing the residue to the air, the presence of muriate of lime will be known by its at tracting moisture.
76. Muriate of Magnesia. Separate the sulphuric acid by baryta, filter, evaporate to dryness, and dis solve the residue in alcohol. Again evaporate and dis solve in water. If muriate of magnesia be present, it will be dissolved, and if carbonate or lime cause no pre cipitation, and if no precipitate be formed by evapora tion and the addition of sulphuric acid and alcohol, then the fluid contains only muriatic acid and magnesia, in union with each other. But, along with these, there may be nitric acid, and lime or alumina, or both. We must therefore determine if, in this case, the muriatic acid and magnesia be in combination with each other. For this purpose, precipitate the lime by evaporation, and by the addition of sulphuric acid and alcohol, and drive off the acid with which it was in union, by boil ing ; then add oxalic acid, and the magnesia will be thrown down in the course of 24 hours. Subject the fluid to distillation, and ascertain if it contain muriatic acid, (43) ; if it does, then the fluid contained muriate of magnesia.
77. Muriate of alumina. If any free alkali be present, saturate it with nitric acid ; then separate the sulphuric acid by nitrate of baryta. If the fluid after this give a precipitate with carbonate of lime, it contains muriate of alumina, or muriate of iron. Whether it be alumina or iron, or perhaps both, may be known by dissolving the precipitate in muriatic acid, and applying the tests of these substances, (50, 53.) Of the Methods followed for ascertaining the quantities of the different compounds contained in Mineral Wa ters.