CHAPTER VII.

On Mineral Waters.-Distinctive Character of Mineral Waters.Therapeutic Importance of Mineral Waters.-Chemical Character of their Respective Mineral Impregnations.—Classification of Mineral Waters: Saline, Sulphureous, Carbonated or Alkaline, and Chalybeate.-Thermal Mineral Waters.-Principal Mineral Waters of Great Britain and Continental Europe.-The Mineral Waters of England considered in further detail, as to their Localities, the Chemical Nature of their Saline and Gaseous Impregnation, and their Therapeutic Effects: Buxton, Matlock, Bakewell, Bath, Bristol, Cheltenham, Leamington, TunbridgeWells, Harrogate, &c. - Stimulating Effects of the several Mineral Waters.-Inferential Suggestions as to the Medicinal Treatment of Chronic Diseases.

MINERAL waters act remedially on many of the disordered conditions of the human body, particularly on those which are of chronic character, or in a chronic stage; they assist efficiently, in many cases, the therapeutic effects of climate and change of air, and the other means which have been considered in the preceding Chapters; and they often exercise a marked curative influence on morbid states of the system, which other means have failed to relieve, even when aided by the appliances of medicine. The mineral waters deservedly occupy an important position among the means of health, and are rightly considered to be nothing less than the great dispensaries of nature.

CHARACTERISTICS OF MINERAL WATERS. 245

The mineral waters in general appear to differ from the other forms of terrestrial water, in the constant amount of their mineral impregnation, and its unvarying character. Even sea-water is said to differ much in different localities, as to the amount of the solid matter held in solution. The water of the Mediterranean is reported to contain a larger amount of saline matter than that of the British Channel; and this, than the water of the German Ocean; and this, than the water of the Baltic. Whether this opinion be eventually ascertained to have been well founded or not, in the instance of the waters of rivers, lakes, and springs, and even in that of rain-water, the greatest differences in their degree of purity are found to obtain, under different circumstances as to temperature, character of vegetation, the quantity of rain that may have fallen recently, &c. Moreover, the amount of mineral impregnation, or of alkaline, calcareous, saline, chalybeate, or gaseous matters, contained in the common terrestrial waters, is sometimes greater than that which is contained in many mineral waters of established character for their medicinal effects; but the variable amount of the mineral impregnation in the common terrestrial waters, and frequently the very variable character of such impregnation, forms an important distinction between these waters and the generality of the mineral waters strictly so called. In illustration of this, the thermal waters of Buxton were analysed in the year 1784, and again, with the aids of an advanced science, in 1820; and in both cases, the same amount of mineral impregnation

was found to characterise them: the same remark applying to the different analyses of the more important of the mineral waters that have been made at different periods, when they have been conducted with sufficient care and skill to be of a trustworthy character. In the case of thermal waters more particularly, but the observation may be extended to many of the cold mineral waters,-even the quantity of the water poured out from the several springs at different periods of the year, under the different atmospherical circumstances of hot weather and cold, wet weather and drought, may not be found to vary in any degree; showing, very conclusively, that the waters to which this observation is applicable, are not in any degree dependent on the rains for their supply, but are altogether derived from some other source ;whether that source be or be not a conduit leading directly from the ocean; by which the water is conveyed to the fault, or rupture in the stratification, through which the mineral water escapes finally to the surface. If this view be admitted to be the most feasible solution of this problem that has ever been advanced, there is no difficulty in understanding how the waters of the ocean might be deprived of all their saline constituents, by having to percolate extensive beds of gravel, or other porous strata, which would have the effect of removing any amount of saline impregnation such water might contain. Any degree of mineral impregnation would be subsequently given to such water by the strata through which it might thereafter have to pass, supposing such

CHARACTERISTICS OF MINERAL WATERS. 247

strata to contain soluble materials; and any degree of elevated temperature by which such mineral water might be characterised, might, with sufficient probability, be ascribed to the circumstance of its having passed through strata at a given depth below the surface of the earth. By ascertaining the temperature of the rocks at different depths below the surface, it has been inferred "that the earth becomes warmer by one degree for every forty-four feet of depth, stating it in round numbers; and, consequently, at a depth of not more than a few thousands of feet, the temperature of the earth may be such as would raise water to the boiling heat of 212°: enough has been ascertained to justify the conclusion that this would be the case at a depth of little more than 7000 feeta depth that bears no greater proportion to the earth's diameter, than a few inches bear to a mile. These views, as to the origin of the tepid mineral waters, and the source of their elevated temperature, are confirmed by the circumstance, that thermal springs are found in the greatest abundance in the neighbourhood of active or recently active volcanoes, and that volcanoes are hardly ever found to exist without giving rise to springs of tepid water. And in those situations where no traces of volcanic agency can be detected in the neighbourhood of tepid springs, these waters are always found to issue from the primary rocks, chiefly from granite, either directly, or from beds of inconsiderable thickness, which evidently form a mere crust over rocks of the primary class." *

* Buxton and its Waters.

From the earliest ages, mineral waters have been resorted to by mankind, as great and trustworthy means of relieving or curing diseases; and, in all ages, and under all the different and varying circumstances of mental darkness and enlightenment, of superstition and its worse opposite, of Paganism, Mohammedanism, and Christianity, of the intertropical and the temperate regions of the earth, of the denizens of hills, plains, and valleys,—mineral waters have been found to hold a high place in public confidence. And it is a curious fact, that no country in the world appears to be destitute of mineral waters; and they have been subjected to investigation and study, as to their properties and effects, by chemists and medical men, in Portugal, Spain, France, Switzerland, Germany, Italy, Greece, Great Britain, various districts of Asia, both continental and insular, the continent and islands of Africa, and the continents and the islands of North and South America.

The respective temperature of the different mineral waters is found to range from the comparative cold of some 60°, to the actual boiling heat of 212°; and warm and cold mineral waters are respectively found in almost every country.

Besides the important division of mineral waters into those which are warm and those which are cold, they are further divided according to their predominant principle, or most characteristic effect on the animal economy, into the saline, the chalybeate, the sulphurcous, the calcareous, and the acidulous. This division is, in most cases, sufficiently justifiable,