By these different steps we ascertain the quantity of the different ingredients. We must next ascertain the state of combination in which they existed. This is done, by supposing that the ingredients were so united as to form the most soluble salts. Should other sub stances, besides these mentioned, be supposed to exist in the water, as potassa or alumina, they must be detect ed by their proper test, and their proportions ascertain ed. These, it is supposed, are likewise so combined, as to form with the acids the most soluble compounds. Thus, in his experiments on sea water, Dr. Murray found that a pint of this fluid contained, Lime 2 9 Magnesia 14 8 Soda 96 3 Sulphuric acid . . . 14.4 Muriatic acid . . . 97.7 226.1 These, he inferred, existed in the water in the state of muriate of soda, muriate of lime, muriate of magnesia, and sulphate of soda. The quantity of sulphate of soda equivalent to 14.4, of sulphuric acid is 25.6 ; the re mainder of the soda 85.1 is united with 74.2 of muriatic acid, to form 159.3 of muriate of soda. The quantity of muriate of lime, equivalent to 2.9 of lime, is 5.7. The 14.8 of magnesia is combined with the remainder of the muriatic acid, to form 35.5 muriate of magnesia.
The saline contents, then, according to this way of de termining the compounds, are Muriatc of soda . . 159.3 Muriate of magnesia 95.5 Muriate of lime . . 5.7 Sulphate of soda . . 25.6 226.1 In the same way, having ascertained the proportions of the different ingredients in any mineral water, the quantities of the compounds which they form may be ascertained.
If this view of the constitution of mineral waters be correct, the component parts of those analysed will be very different from what has been stated in the foregoing Table, these having been ascertained by the evaporation of the fluid, and by the other methods usually followed in the analysis of mineral waters. Thus those which have yielded sulphate of lime and muriate of soda, it is inferred, contain muriate of lime and sulphate of soda, the two former having been generated during the eva poration by the decomposition of the latter. The quan tities of the substances contained in the water may be ascertained, by finding the equivalents of the different compounds. Thus 100 of sulphate of lime are equiva lent to 81.5 of muriate of lime ; and 100 muriate of soda are equivalent to 122 sulphate of soda.*