in natural history, is used, in general, for all fossil bodies, whether simple or compound, dug out of a subterraneous mine, from which it takes its denomination.
MINERAL Waters, in medicine, all those wherein any medicinal virtues, besides those of common water, are found.
These mineral waters are of various kinds, but they are considered under the general titles of chalybeate, purgative, and alterative. The more-useful and commodious additions for examining these three kinds of mineral waters, are, according to Dr Shaw, galls, syrup of violets, and oil of tartar per deliquium. Galls discover in them any small proportion of vitriol or dissolved iron, as having the property of immediately striking a purple or black colour in all waters where any such substance is lodged. Spirit of violet, in the same fame manner, discovers any small predominancy of an acid or alkali therein, by changing the water red if acid, and green if alkali prevails. Oil of tartar discovers any small proportion of earthy matter less capable of dissolving in water than that salt, by precipitating such earthy matter in form of a white cloud to the bottom of the containing glass, where it collects and appears like a subtile white powder.
These particulars may be shewn, and proved satisfactorily, by adding to pure water a little of a known acid, alkali, dissolved iron, and subtile earth, or fine light sediment of an earthy water; applying the syrup of violets, galls, and oil of tartar respectively.
Mineral waters are imitable by art. The rule is, by a proper analysis to find the contents of such water (by evaporation, the addition of tingling ingredients, &c. as above mentioned) and their proportions; then, by means of synthetical chemistry, to compose a similar mixture: thus, for example, we learn by a proper analysis, that the ingredients, or different constituent parts of Pyrmont waters, are a subtile aqueous fluid, a volatile iron, and a predominating alkali, all joined together in one brisk pungent spirituous water. The imitation of this kind of chalybeate water, is by much the most difficult, and may perhaps be rendered most perfect, by boiling the purest common water in a close vessel, with a small proportion of ochre, soft iron ore, or pyrites.
The imitation of the common purgative mineral waters is easy; thus Epsom water is imitated by barely dissolving three or four drams of Epsom salt in a quart of pure water, made somewhat brisk or quick with a few drops of spirit of vitriol and oil of tartar per decilquium, so as to let the alkali prevail.
The imitation of the alterative waters, such as those of Bath, Buxton, &c. has hitherto scarce been attempted, nor can be rationally, for want of their respective just analysis, upon which such imitation should always be grounded.
As to the use of mineral waters, the learned Heister observes, that in general they are found to agree much better with persons in the middle stages of life, than with persons very old or very young. If any general rule can be given in this case, it is, that people should not take them when younger than eighteen, or older than sixty.