The baths of Aix, so famous in antiquity, were quite demolished by the irruptions of the barbarians. The very source of the water was lost, till the beginning of the present century (I think the year 1704), when it was discovered by accident, in digging for the foundation of a house, at the foot of a hill, just without the city wall. Near the same place was found a small stone altar, with the figure of a Priapus, and some letters in capitals, which the antiquarians have differently interpreted. From this figure, it was supposed that the waters were efficacious in cases of barrenness. It was a long time, however, before any person would venture to use them internally, as it did not appear that they had ever been drank by the antients. On their re-appearance, they were chiefly used for baths to horses, and other beasts which had the mange, and other cutaneous eruptions. At length poor people began to bathe in them for the same disorders, and received such benefit from them, as attracted the attention of more curious inquirers. A very superficial and imperfect analysis was made and published, with a few remarkable histories of the cures they had performed, by three different physicians of those days; and those little treatises, I suppose, encouraged valetudinarians to drink them without ceremony. They were found serviceable in the gout, the gravel, scurvy, dropsy, palsy, indigestion, asthma, and consumption; and their fame soon extended itself all over Languedoc, Gascony, Dauphine, and Provence. The magistrates, with a view to render them more useful and commodious, have raised a plain building, in which there are a couple of private baths, with a bedchamber adjoining to each, where individuals may use them both internally and externally, for a moderate expence. These baths are paved with marble, and supplied with water each by a large brass cock, which you can turn at pleasure. At one end of this edifice, there is an octagon, open at top, having a bason, with a stone pillar in the middle, which discharges water from the same source, all round, by eight small brass cocks; and hither people of all ranks come of a morning, with their glasses, to drink the water, or wash their sores, or subject their contracted limbs to the stream. This last operation, called the douche, however, is more effectually undergone in the private bath, where the stream is much more powerful. The natural warmth of this water, as nearly as I can judge from recollection, is about the same degree of temperature with that in the Queen's Bath, at Bath in Somersetshire. It is perfectly transparent, sparkling in the glass, light and agreeable to the taste, and may be drank without any preparation, to the quantity of three or four pints at a time. There are many people at Aix who swallow fourteen half pint glasses every morning, during the season, which is in the month of May, though it may be taken with equal benefit all the year round. It has no sensible operation but by urine, an effect which pure water would produce, if drank in the same quantity.
If we may believe those who have published their experiments, this water produces neither agitation, cloud, or change of colour, when mixed with acids, alkalies, tincture of galls, syrup of violets, or solution of silver. The residue, after boiling, evaporation, and filtration, affords a very small proportion of purging salt, and calcarious earth, which last ferments with strong acids. As I had neither hydrometer nor thermometer to ascertain the weight and warmth of this water; nor time to procure the proper utensils, to make the preparations, and repeat the experiments necessary to exhibit a complete analysis, I did not pretend to enter upon this process; but contented myself with drinking, bathing, and using the douche, which perfectly answered my expectation, having, in eight days, almost cured an ugly scorbutic tetter, which had for some time deprived me of the use of my right hand. I observed that the water, when used externally, left always a kind of oily appearance on the skin: that when, we boiled it at home, in an earthen pot, the steams smelled like those of sulphur, and even affected my lungs in the same manner: but the bath itself smelled strong of a lime-kiln. The water, after standing all night in a bottle, yielded a remarkably vinous taste and odour, something analogous to that of dulcified spirit of nitre. Whether the active particles consist of a volatile vitriol, or a very fine petroleum, or a mixture of both, I shall not pretend to determine: but the best way I know of discovering whether it is really impregnated with a vitriolic principle, too subtil and fugitive for the usual operations of chymistry, is to place bottles, filled with wine, in the bath, or adjacent room, which wine, if there is really a volatile acid, in any considerable quantity, will be pricked in eight and forty hours.