CHAP. 1. gree of heat, which could not happen, if it was produced by chemical combinations of materials near the surface of the earth.

Mineral Waters.

"2. In the very dry summer of 1780, when all the cold springs in this part of the country either totally ceased, or were much diminished, I was well informed on the spot, both at Matlock and Buxton, that the warm springs had suffered no observable decrease of their water. Whence I conclude, that the sources of these warm springs were at a much greater depth below the surface of the earth than the cold ones; and that, on that account, the water must first have been raised in the form of steam from those greater depths. Another circumstance shows, that the source of many of these waters is situated beneath the origin of the cold springs; even after the steam which produces them is condensed into water; which is, that their heat continues always the same both in winter and summer, in wet seasons and in dry; evincing, that no cold water from the dews, or springs in consequence of them, is mixed with these sources of warm water, &c.

"3. The rocks of limestone in all this part of the country abound with perpendicular clefts, in which are found the ores of zinc, lead, and copper; and it is hence probable, that not only the steam of water at present, which produces these warm springs, but that those metals themselves, and the fluor, or baroselenite, which attends them, have, in former ages, been raised into those perpendicular clefts by the great subterraneous fires, which raised the continents and islands from the primeval ocean.

"4. The existence of central fires in the earth in the early ages of the world, is demonstrated by the elevation of the solid parts of the globe above the ocean, and the shattered condition of its strata, with the immense masses of lava then produced, which go under the names of toadstone, basaltes, moor-stone, porphyry, and granite, as are so well explained in Mr. Whitehurst's and in Dr. Hutton's Theories of the Earth. The present existence of central fires seems probable from the many volcanoes, which are spiracula, or chimnies, belonging to those great fires; and it is probable, that by the escape of elastic vapours from these, is owing the small extent of modern earthquakes, compared with those of remote antiquity, the vestiges of which remain all over the globe. Another argument for the present existence of immense subterraneous fires, is, that the great earthquake at Lisbon produced undulations on the lakes of Scotland; and was felt in the mines of Derbyshire; (Philos. Transact.) which could not easily happen, but by a percussion on one side of a confined fluid lava, which would be propagated to the other; as striking the gentlest blow on one side of a bladder distended with water, is felt by the hand placed on the other side: to which may be added, that in some mines the deeper you descend, the warmer you perceive them, &c.

"5. Because there are springs of hot water in all countries, where open volcanoes evidently exist: whence from analogy we may conclude, that the hot springs in countries where open volcanoes have existed, but are not now open, are owing to the same cause acting in a less powerful manner.

"6. Add to this, that if those waters had been heated by the chemical decomposition of pyrites, some of them at least would probably have retained a strong chalybeate taste, or sulphureous smell; or that they would all of them have been impregnated with some similar material, which, on

the chemical analysis of these waters of Buxton and Matlock, does not ap- CHAP. 1. pear to be the fact.

Mineral

"7. I come now to another circumstance, which very much corrobo- Waters. rates the above theory of the production of these springs from the steam raised from deep subterraneous fires, and not from any decomposition of pyrites. The strata in this part of Derbyshire consist of beds of limestone, and of lava (or toadstone) which lie reciprocally one above the other. Now if we suppose the steam rising from subterraneous fires to be owing partly to water slowly subsiding upon those fires, and to limestone gradually calcined by them, it must happen, that the steam rising through the perpendicular clefts in the supercumbent rocks, must be replete with calcareous gas, (fixed air) or with some phlogisticated air.*

"If this steam, so impregnated, be condensed in limestone strata, the fixed air in this hot steam will super-saturate itself again with calcareous earth. Now this is what precisely happens to the waters of Matlock, which are replete with calcareous particles, as appears by the copious deposition of tupha, or calcareous incrustations, along the channels in which they flow. For, in general, it happens, that springs of water wear themselves valleys from their sources, as is done by the water at Buxton; but those springs at Matlock have produced rocks and mountains of a spongelike calcareous stone between their fountains and the Derwent, with which all the houses at Matlock are constructed, and many of the stone fences.

"In the beginning of October, 1780, I was present, with my friend Mr. Edgeworth, at the opening of two of the springs at Matlock, about 200 yards above their usual places of appearance. We found them both at these new openings about one degree of heat, or somewhat more, warmer than at their places of usual exit. The upper one, which could be best seen, issued from some cracks or fissures in the upper surface of a bed of toadstone, and between it and the blue marl which lies over it; under which marl it seems to have been condensed, and thence to have supersaturated itself with calcareous particles. I examined this marl by means of acids, and found it to be calcareous, except some shining bits of whitish pyrites, which had no appearance of being in a state of decomposition.

"On the contrary, the steam which produces the water at Buxton, is probably condensed in the substance of the toadstone, or lava, and not in a stratum of marl or limestone, like the Matlock water; and hence the great difference of their contents. As one edge of these strata of limestone and lava, wherever there are springs, is always elevated higher than the other, it would be easy, by attending to the inclination of these strata, to discover

"Dr. Priestley, from five ouncesof limestone, obtained 1160 ounce-measures of air, ninetenths of which was fixed air, and the other tenth phlogisticated air. From four ounces of whitespar he obtained 830 ounce-measures of air; the first portion of which had but one-fourth of fixed air; which, however, varied in the course of the experiment, being once three-fourths, then one-half, then one-third of fixed air."

↑ "It may seem extraordinary that fixed air, or calcareous gas, which is known to precipitate lime from water, should render limestone more soluble in water. This, however, is evinced by the experiments of Mr. Cavendish, who added to lime-water, which had been rendered turbid by means of calcareous gas, more of the same gas, which enabled the water to re-dissolve the precipitated limestone. Water, by a large quantity of calcareous gas, will thus, in close vessels, super-saturate itself with lime; which will gradually precipitate in the form of limestone, when exposed to the air, by the evaporation of the superfluous gas."

Mineral Waters.

CHAP. 1. on which side of the bath is situated the mountain in which the steam is condensed, which probably may not be more than a mile or two from the eruption of the springs; because, on opening the springs at Matlock at a place about 200 yards above the Wells, the water (though already collected into a kind of vein) was cooled more than a degree; and this cooling must proceed much faster where the water is diffusely and thinly spread between two contiguous strata: and further, as the progress of this water must warm in some degree the surface of the earth, beneath which it passes after its condensation, and particularly at the place of its condensation, it is not improbable but its course might be detected by observations made in rhymy mornings, or when snow has lain long on the ground, by the melting or disappearing of it first in that part; or, perhaps, by the earlier vegetation of the grass or trees on those parts of the surface. A Mr. Taylor, who once kept this bath, produced early vegetables, by conveying a stream of the warm water under a border of his garden. If this source should ever be discovered by mining, I suppose the water, by being received nearer the place of its devaporation, would be found of a greater degree of heat, from 82, its present heat, up to 212, or the heat of boiling water.

"The contents of the waters of Buxton and Matlock must countenance the theory above delivered; for if steam be raised from subterraneous furnaces, where limestone is probably in a state of calcination, much calcareous gas, or fixed air, and some phlogisticated air, would arise with the aqueous steam: these are found in the Buxton water, in the loose state of bubbles, according to the analysis of Dr. Pearson; and in this the Buxton water resembles the waters at Bath, which are said, by Dr. Priestley, to possess similar kinds of air; and as these airs seem to be the principal ingredients of both these waters, there is reason to believe, both from this circumstance, and from their success in relieving similar diseases, that their medicinal powers are very similar, &c.

"In the Buxton water the fixed air is found in loose bubbles, because it does not meet with any kind of calcareous earth, or limestone, to combine itself with in the Matlock water the contrary occurs; it has no loose airbubbles, because the fixable air is combined with lime, and thus this water is replete with calcareous earth in subtile solution; and in this respect I suppose resembles the Bristol water.

"By the experiments of Bergman and Scheele, it appears that the stony concretions in animal bodies consist of saccharine acid and air, and that this acid has a greater affinity than any other to calcareous earth.* Now as the saccharine acid is perpetually generated in the stomach during the digestion of our aliment, it is probable that the salutary effects of these

"I cannot leave this account of calcareous or hard waters without adding, that I suppose, from the great affinity between calcareous earth and saccharine acid, may be explained a circumstance, the theory of which has never been understood, and therefore the fact has generally been doubted; and that is, that hard waters make stronger beer than soft ones. I appeal to the brewers of Burton for the fact, who have the soft water of the Trent running on one side of their brewhouses; and yet prefer universally the hard or calcareous water supplied by their pumps. I suppose there may be some saccharine acid in the malt (which is not all of it equally perfectly made into sugar by the vegetable digestive power of the germinating barley) which, by its attracting the calcareous earth of hard waters, may produce a kind of mineral sugar, which, like the true sugar, may be convertible into spirit: for a similar purpose, I suppose lime is used by the sugar-bakers in refining their sugars, though the theory of its effects is unknown to them."

calcareous waters, such as Matlock and Bristol, may be owing to their CHAP. 1. saturating the super-abundancy of this saccharine acid, and that thus they Mineral may prevent the tendency which some of our fluid secretions possess, of Waters. producing calculous, and perhaps gouty and bilious concretions; and prevent the increase in size of those already formed: on the same principle they may tend to render purulent matter less acrimonious, as they are supposed to be of advantage in pulmonary and scrophulous ulcers, &c."

The most in repute of the sulphureous waters of Derbyshire rises in the park of Lord Scarsdale, at Kedleston. In a glass it looks very clear and transparent; but in the well, it appears of a blackish blue colour, tinged with purple; and any substance thrown into it, assumes the same appearance. That it is impregnated with sulphur, in some state or form, is not only evident from its strong taste and smell, but likewise from its changing silver to a dark copper colour: and in its passage from the well, a whitish sediment is deposited, which has the appearance of sulphur. That it is also impregnated with other substances, is proved by the experiments of Dr. Short, who observes, that eight pints evaporated, left two scruples of sediment, twenty-one grains of which were a dark brownish earth, and the rest salt in these respects it appears similar to the water at Harrogate.

Kedleston water is principally valued for its anti-scorbutic qualities. When taken inwardly, it acts as a diuretic, and has given relief to persons afflicted with the gravel. It has also been found efficacious, from external application, in various cutaneous diseases, but more especially in ulcerous complaints. In the summer it is frequently used by the inhabitants of Derby as a substitute for malt liquor, at their meals: the charge of carriage (one penny per quart) affording sustenance to a few poor people of the neighbourhood. The temperature of the spring is about forty-seven degrees. Several other sulphureous springs rise in different parts of the county, but have hitherto undergone very little examination.

The chalybeate waters are numerous; but the most celebrated spring of this nature is at Quarndon, about three miles from Derby. Persons of a weak and relaxed habit have been much benefited by its use: when taken in sufficient quantity, it generally operates as a purgative; yet, to produce this effect, exercise is sometimes necessary. From the experiments made by Dr. Short, it appears, that a pint contains one grain of fixed salt; and that two gallons, when evaporated, leave half a dram of a light-coloured sediment, half of which is nitrous earth. Its temperature is nearly fortynine and a half. Within 200 yards of the warm spring at Buxton, there is a chalybeate water of similar properties to that at Quarndon; the most essential difference is, that the fixed air, by which the iron is held in solution in the latter, may be set at liberty with a more moderate degree of heat than is requisite for the same purpose in that at Buxton: its taste, also, is less rough and irony. Other chalybeate waters are found at Morley, Chesterfield, Tibshelf, Duffield, and Bradley.

In the liberty of Heage, about midway between Crich and Belper, is a martial vitriolic spring, the only one that has yet been found in this county. It is situated on a black boggy soil, and was discovered about thirty years ago by a labouring man, who was employed in forming a sough to drain some of the neighbouring grounds. He had long been afflicted with an

Mineral
Waters.

CHAP. 1. ulcerous disorder in one of his legs, but observed, that during the continuance of his labour, it gradually disappeared, and by the time his undertaking was completed, he had received an entire cure. This induced a supposition that the spring was possessed of medicinal properties, and when examined, the fact became evident from the vitriolic taste of the water. It has been thought to contain fixed air in some quantity; not only from the number of bubbles which may be seen in it, when first poured into a glass at the spring, but likewise from the circumstance, that when tightly enclosed in a cask or bottle, it will break either with a slight degree of agitation; an effect attributed to the efforts of the fixed air to make its escape. Besides the beneficial efficacy of Heage water in ulcerous diseases, it has been found useful in stopping inward bleedings; and when applied outwardly, is said to have this effect, as soon, and completely, as extract of Saturn.*

Ebbing and flowing Well.

The ebbing and flowing Well is situated nearly midway between Chapelen-le-Frith and Tideswell, close to the south side of the turnpike road, and immediately under a steep hill, which rises to the height of more than one hundred feet. The well is merely a small pool, of an irregular form, but nearly approaching to a crescent shape, with flat stones placed edgeways, apparently intended as a watering place for cattle, from two to three feet deep, and about six or seven yards in width. The motion of the water, from which it has obtained its name, is by no means regular, but seems to depend on the quantity of rain which falls in the different seasons of the year. In very dry seasons, it has sometimes ceased to flow for two, three, or four weeks together; and several instances of this kind have been observed within the last thirty or forty years. Sometimes it flows only once in twelve hours; but at others, every hour; and in very wet weather, perhaps twice or thrice within that time. When it first begins to rise, the current can only be perceived by the slow movement of the blades of grass, or other light bodies that float upon the surface: yet, before the expiration of a minute, the water issues in considerable quantity, with a guggling noise, from several small apertures on the south and west sides. The interval of time betwixt the ebbing and flowing is generally stated to be four minutes and a half: the quantity of water it discharges at different periods also varies. In October, 1802, after a few showery days, it flowed and ebbed once in about three quarters of an hour; the whole time it continued to flow was four minutes and a half. In this space it rose more than five inches; and would probably have been three times that height, if the water had been confined; but as one side of the pool is lower than the other, the water falls into a ditch that skirts the road. Having ceased to flow, it remained a few seconds stationary, and then began to run back. The retro

We have been favoured by Dr. Gilbert with the following additional remarks. The waters of Matlock, like those of Bristol and Buxton, are of the calcareous class. When taken at the fountain, long experience assigns them highly restorative, strengthening, and curative powers; especially in pulmonary cases and nervous disorders. Ancient and modern practice alike direct the use of the Hot Baths, as the most powerful agent in the preservation of health, in the cure of rheumatism, and in the greater portion of inflammatory, acute and chronic disorders. Almost all nations of the remotest antiquity have had their Warm Baths. The northern nations from the Hot Bath plunge into snow, proving the power acquired by warm bathing in resisting cold and the vicissitudes of temperature.