rich in carbonic anhydride; (_f_) sulphuretted waters, which contain hydrogen sulphide. Sulphuretted waters may be recognised by their smell of rotten eggs, and by their giving a black precipitate with lead salts, and also by their tarnishing silver objects. Aërated waters, which contain an excess of carbonic anhydride, effervesce in the air, have a sharp taste, and redden litmus paper. Saline waters leave a large residue of soluble solid matter on evaporation, and have a salt taste. Chalybeate waters have an inky taste, and are coloured black by an infusion of galls; on being exposed to the air they usually give a brown precipitate. Generally, the character of mineral waters is mixed. In the table below the analyses are given of certain mineral springs which are valued for their medicinal properties. The quantity of the substances is expressed in millionths by weight. Column Headings: A: Calcium salts B: Sodium chloride C: Sodium sulphate D: Sodium carbonate E: Potassium iodide and bromide +-------+-------+--------+-------+-------+-----+------+ | | | | | | | | | | [A] | [B] | [C] | [D] | [E] | [F] | | | | | | | | | +-------+-------+--------+-------+-------+-----+------+ | | | | | | | | | I. | 1,928 | -- | 152 | -- | -- | 24 | | II. | 816 | 386 | 1,239 | 26 | -- | 43 | | III. | 1,085 | 1,430 | 1,105 | -- | 4 | 90 | | IV. | 343 | 3,783 | 16 | 3,431 | -- | 14 | | V. | 3,406 | 15,049 | -- | -- | 2 | -- | | VI. | 352 | 3,145 | -- | 95 | 35 | 50 | | VII. | 308 | 1,036 | 2,583 | 1,261 | 4 | 178 | | VIII. | 1,726 | 9,480 | -- | -- | 40 | 120 | | IX. | 551 | 2,040 | 1,150 | 999 | -- | 1 | | X. | 285 | 558 | 279 | 3,813 | -- | -- | | | | | | | | | | XI. | 340 | 910 | Iron and aluminium {1,020 | | | | | sulphates: {1,660 | +-------+-------+--------+----------------------------+ Column Headings: G: Iron carbonate H: Magnesium salts I: Silica J: Carbonic anhydride K: Sulphuretted hydrogen L: Total solid contents