To the taste it is very agreeable, and when drunk in moderate quantity, it exhilarates the spirits, increases the appetite, and produces no particular determination to the bowels. It is to the strong impregnation with carbonic acid, and the small proportion of soda which it contains, that its most important benefits are owing.
If it be closely corked and sealed, Seltzer water may be kept without injury, or even alteration, for a very considerable time; but, if exposed to the air, it soon becomes fetid. It is used as a common drink at table in many parts of Germany and Holland, and is even brought into England in stone bottles, each containing about three pints. A large proportion of Seltzer water, either genuine or artificial, is consumed in this country.
8. CHALYBEATE WATERS.
292. Are such as contain a portion of iron. This is easily detected by the property which it has of striking a black colour with tincture of nutgalls.
293. TUNBRIDGE WATER is a carbonated chalybeate, the small portion of iron which it contains being held in solution by carbonic acid ([26]). It is, however, neither brisk nor acidulous. To the taste it is simply chalybeate; and that only in a slight degree.
Its foreign contents are oxide of iron ([21]), a small portion of common salt, muriat of magnesia, and sulphat of lime ([192]), carbonic acid gas or fixed air ([26]), and other gases, but these only in small quantity.
Tunbridge Wells is a populous village, situated in a sandy but romantic valley in the county of Kent, about five miles from the town of Tunbridge, and thirty-six miles south of London. There are, at this place, many chalybeate springs, all of which nearly resemble each other in their chemical properties. Two of them, however, are chiefly used, each of which yields about a gallon of water in a minute.
When first taken from the stone basin into which it flows, the water is perfectly clear and bright, and exhales no particular smell. It does not sparkle in the glass, but a few bubbles slowly separate, and adhere to the sides of the vessel. When it has stood for some hours exposed to the air, it becomes turbid, and otherwise undergoes a very material change. As it does not properly curdle soap, it may be denominated a soft water.
The original discovery of this water, as to its medical properties, is usually considered to have been in the reign of James the First. The season for drinking it commences as early as March or April, and continues till November.
294. SPA WATER, the celebrity of which has given a general appellation to most other mineral springs, is a highly carbonated chalybeate water, which contains a great proportion of carbonic acid ([26]). It has an agreeable acidulous taste, mixed with a strong impression of chalybeate, which remains on the palate for a considerable time after it has been drunk.