To ascertain the quantity of earthy and saline matter contained in water, the following is the most simple and easy method. EXPERIMENT. Put any measured quantity of the water into a platina, or silver evaporating basin, the weight of which is known, and evaporate the water upon a steam bath, at a temperature of about 180 deg., nearly to dryness; and, lastly, remove the basin to a sand bath, and let the mass be evaporated to perfect dryness. The weight of the platina basin being already known, we have only to weigh it carefully. When the solid saline contents of the water is attached to it, the increase of weight gives the quantity of solid matter contained in a given quantity of the water. EXPERIMENT. Pour upon the saline contents a quantity of distilled water equal to that in which the obtained salts were originally dissolved. If the whole saline matter become dissolved in this water, there is reason to believe that the saline matter has not been altered during the evaporation of the water. But if a portion remain undissolved, as is usually the case, then we may conclude that some of the salts have mutually decomposed each other, when brought into a concentrated state by the evaporation, and that salts have been formed which did not originally exist in the water before its evaporation. We have already mentioned that almost the only salts contained in common waters, are the carbonates, sulphates, and muriates, of soda, lime, and magnesia; and sometimes a very minute portion of iron. Having determined the different acids and bases present, in the manner stated at p. 49, we may easily ascertain the relative weight of each. The following formula suggested by Dr. Murray,[17] is fully as accurate a means of analysing waters as any other, and it is easy of execution. The weight of the saline ingredients of a given quantity of water being determined, we may proceed to the accurate analysis of it in the following manner. EXPERIMENT. Measure out a determinate volume of the water (as 500 or 1000 cubic inches,) and evaporate it gradually, in an unglazed open vessel defended from dust, to one third of its original bulk; then divide this evaporated liquid into three equal portions. EXPERIMENT. Drop into the first portion, muriate of barytes; wash the precipitate, collect it, dry it at a red heat upon platina foil, and weigh it; digest it in nitric acid, dry it, and weigh it again. The loss of weight indicates the quantity of carbonate of barytes which the precipitate contained. The residual weight is sulphate of barytes; the carbonic acid in the water is equivalent to 0,22 of the weight of the carbonate of barytes; the sulphuric acid to 0,339 of the weight of the sulphate of barytes. EXPERIMENT.