The sulphureous waters are very powerful and active remedies; as the sulphur, in the attenuated form which it assumes in its combination with inflammable air, is conveyed to the smallest vessels. These waters have been long employed in diseases of the,skin; and, as they are used both externally and internally, they produce very considerable effects. In gouty swellings and diseased joints from this and other causes, the warm sulphureous waters are highly useful; in the chronic pains from gout, rheumatism, contractions, or indeed any cause, they afford considerable relief. They are supposed particularly effectual in diseases produced by arsenic, lead, or mercury: but we suspect that this opinion rather arises from the power of sulphur on metals out of the body, than from actual observation. In such diseases, the metal seems to be soon discharged out of the system, and the effects only remain.

Modern refinement, perhaps modern theory, has added another group of complaints to those which are likely to bebenefited by sulphureous waters, viz. the diseases arising from too great a proportion of oxygen in the system. Pathologists have not traced this cause very extensively; but it has been supposed to occasion the diabetes melli-tus, and in hectics the florid blood seems to show that the fluids are highly oxygenated. In the former, Dr. Rollo advised the hepatised ammonia; and other authors have thought that the same object might be more conveniently attained by these waters. We know not that they have been employed in hectic, but air of a lower quality than that of the atmosphere seems occasionally useful; and we strongly suspect that the credit of the Bristol waters has been lessened, since it has been fashionable to reside nearer the summit of the hill.

Of the bituminous waters we have had little experience, and need not enlarge. We perceive in some authors, that water impregnated with what is called fossil oil occur in this kingdom and in different parts of the continent. In our own country the waters of Brosely, Pitchford, and Wigan, are enumerated; in France, those of Gabian and Plombieres; in Germany, that of Waldsborn. In fact, the accuracy of modern chemistry has not yet sufficiently illustrated the nature of several mineral springs; nor are the medical reports wholly free from suspicion of superstitious, prejudiced, or interested exaggeration. We have, consequently, preferred giving the general outlines of the analysis, with the knowledge to be drawn from the sensible qualities of the water respecting its ingredients, to the list of mineral waters, with which we had purposed to conclude the present article.

The metallic impregnations only remain, and under this head we purpose to speak more particularly of the Bath waters. These springs have been long and highly esteemed; but the chemist has been disappointed in finding so little foundation from his analysis for the character they have for so many centuries enjoyed. This water consequently furnishes a strong argument in favour of those who consider the attenuated form of the impregnation as the chief source of the benefit arising from it. Simple warm water has indeed been substituted, and many are the virtues attributed to it in assisting digestion. Such it may possess; but till it produces all the varied effects of the Bath waters, we shall have little confidence in the refinement. Every physician, who wishes to distinguish himself at Bath, writes on its waters, and endeavours to add to the stock; yet we are still little acquainted with the volatile ingredients which occasionally produce giddiness, and, when improperly used, fever. It is not very unreasonable to presume that it is inflammable or azotic gas. The iron is in a small proportion; and a late author, who has plumed himself on the discovery of silex in this water, has advanced very little in the discovery of the cause of its powerful effects. Bath waters are certainly warm and tonic: in the arthritic weakness of the stomach they are highly useful; in palsy, if the effects of the stimulating, inebriating principle be avoided, they are very serviceable; in topical weaknesses of the joints they excel almost every other remedy. In the relaxation of the hip joint, we perceive, from the records of the Bath hospital, they have given important relief: in chronic obstructions of the viscera they are equally valuable.

The waters impregnated with vitriolated iron only-are more simply tonic; and the forge water, where the iron seems only mechanically mixed, is chiefly useful as a topical application.

The other metallic impregnations of water are copper, arsenic, and tin: of the two latter however we have no proofs, and we think they have never been discovered. Copper in water chiefly occurs near mines; but we perceive in Ireland the mineral waters at Balle-murtoch and Cronebaum accounted cupreous; and those of Altenburgh, Cement, Goslar, Herengrunde, Neusol, and Schmelnitze, in Germany, are supposed to be of a similar nature. They are used only as topical applications to old ulcers, and sometimes in chronic ophthalmy.

We may perhaps be accused of neglect, for not more particularly noticing the cretaceous waters and the sea water. Of the former,. Bristol waters are a striking and an almost solitary example; nor are we ignorant of different effects supposed to result from its demulcent properties, particularly in hectics and diseases of the bladder. It is sufficient to mention them in this place for the use of those who have more credulity on these subjects than ourselves. We see no other effects from these waters than from a mild pure fluid, which is certainly useful, though' not the only source of the advantages which mineral waters impart. The Bristol springs have been thought serviceable in diabetes: a fact that requires a more ample consideration of the disease than can be admitted in this place.

Sea water has been supposed to possess peculiar power; but if more eminently useful than other saline purgative waters, the advantages chiefly result from its being more easily procured and longer continued. Yet we must remark that common salt is a necessary condiment to many tribes of animals. To man it is equally of importance, since it furnishes the most common and salutary stimulus, so that we may suppose it peculiarly advantageous in diseases. In fact, we find it so; and, where the constitution can bear its action, which is not always mild, it is highly useful. Physicians have supposed that it owes some of its advantages to the bittern, the oily matter which it contains. This cannot be denied, though it is not probable. Yet when we reflect that the salts of marine plants and of other mi productions are often particularly useful asdeobstruents, more so than even the salt itself, we must not deny some peculiar advantages to their pabulum.