84. Alkaline Sulphate*. The quantity of the alkaline sulphates may be ascertained, by freeing the water of the other sulphates, (70,) and then adding the solution of acetate of baryta. 100 grains of the precipitate are equivalent to 74.8 of dry sulphate of potassa, and to 61.2 of dry sulphate of soda.
85. Sulphate of Lime. Add nitric acid, to decompose the carbonates, boil the fluid, and add weak alcohol, the sulphate of lime will be precipitated. It must be then ignited and weighed.
86. Sulphate of Magnesia. If this be the only sul phate present, its quantity may be known by precipi tating the sulphuric acid, and ascertaining the weight of the sulphate of haryta, 100 grains of which = 51 the sulphate of magnesia. if sulphate of lime be like wise in solution, precipitate the lime by carbonate of magnesia, and weigh the precipitate ; then throw clown the sulphuric acid, and ascertain its quantity; subtract from it that which belongs to the lime, obtained by the former precipitation ; the remainder gives the quantity of sulphate of magnesia, 100 of acid uniting with 50 of magnesia. If the fluid contain sulphate of magnesia and sulphate of soda, add soda, and the magnesia will be precipitated. Dry it and weigh it, 100 = 300 grains of dry sulphate of magnesia. lithe fluid contain these three sulphates, add soda, by which the lime and magnesia Av i I be precipitated. Dissolve the precipitate in diluted sulphuric acid, and evaporate to dryness; wash the residue with a little cold water, which will dissolve the sulphate of magnesia, and leave the sulphate of lime. Evaporate the solution, and weigh the residue ; this is the weight of the sulphate of magnesia, the weight of the undissolved matter is that of the sulphate of lime. Should the water also contain sulphate of alumina, the precipitate given by the soda must be treated with ace tic acid, which will dissolve the magnesia ; the magne sia may then be precipitated by soda. If sulphate of iron be present, expose the fluid to the air for some days, and add alumina, the oxide of iron, and the sul phate of alumina are precipitated, and the sulphate of magnesia is left, and may be procured as above.
87. Sulphate of iron. Having ascertained, by boil ing, that the iron is not in union with carbonic acid, precipitate the iron, (53 ) and infer the quantity of sul phate.
88. Muriates. Suppose that the carbonates are thrown down by boiling, and that muriates of lime, magnesia, and alumina are present, add baryta, by which the whole of the three earths will be precipitated. Dissolve the precipitate in muriatic acid, and then ascertain, by the tests, (48, 50. 51,) the quantity of each earth, and infer that of the muriate of each.
100 lime = 196 dried muriatc of lime.
100 magnesia = 238.3 dried muriatc of magnesia.
100 alumina = 317.6 dried nruriate of alumina.
89. When the sulphates are present with the muriates, the tatter must be separated by evaporation to dryness, and treating the residue with alcohol, which will dis solve the men iates; then proceed as above. If sulphate of lime only he present, throw down the sulphuric acid by baryta, and ascertain its quantity, filter the fluid, and proceed as (88.) subtracting the quantity of the sul phate of lime [ruin the lime obtained by precipitation, the remainder belongs to the muriatic acid.
90. NN'hen sulphates of lime and magnesia, and the muriates of soda, magnesia, and alumina are present, throw down the lime and alumina by carbonate of snag nesia, and ascertain the quantity of lime which will give that of the sulphate, (62.) Find out the quantity of sul phuric acid by baryta ; subtract the quantity which we know was in union with the lime ; the remainder will belong to the magnesia, and will chew the quantity of the sulphate of that earth.
91. To another portion of the water, add lime-water, which will throw down the magnesia and alumina; as certain the proportions of these, (63.) that of the alu mina will show the quantity of muriate of alumina. (88 ) Subtract from the weight of magnesia that which we know to belong to sulphuric acid, the remainder will indicate the quantity of muriate of magnesia. By adding baryta, and then carbonic acid, to the fluid, the sulphutic acid and lime will he thrown down, and the quantity of muriate of soda may be ascertained by eva poration.