BOULOGNE, May 23, 1765.

DEAR DOCTOR, - I found three English families at Aix, with whom I could have passed my time very agreeably but the society is now dissolved. Mr. S - re and his lady left the place in a few days after we arrived. Mr. A - r and lady Betty are gone to Geneva; and Mr. G - r with his family remains at Aix. This gentleman, who laboured under a most dreadful nervous asthma, has obtained such relief from this climate, that he intends to stay another year in the place: and Mr. A - r found surprizing benefit from drinking the waters, for a scorbutical complaint. As I was incommoded by both these disorders, I could not but in justice to myself, try the united efforts of the air and the waters; especially as this consideration was re-inforced by the kind and pressing exhortations of Mr. A - r and lady Betty, which I could not in gratitude resist.

Aix, the capital of Provence, is a large city, watered by the small river Are. It was a Roman colony, said to be founded by Caius Sextus Calvinus, above a century before the birth of Christ. From the source of mineral water here found, added to the consul's name, it was called Aquae Sextiae. It was here that Marius, the conqueror of the Teutones, fixed his headquarters, and embellished the place with temples, aqueducts, and thermae, of which, however, nothing now remains. The city, as it now stands, is well built, though the streets in general are narrow, and kept in a very dirty condition. But it has a noble cours planted with double rows of tall trees, and adorned with three or four fine fountains, the middlemost of which discharges hot water supplied from the source of the baths. On each side there is a row of elegant houses, inhabited chiefly by the noblesse, of which there is here a considerable number. The parliament, which is held at Aix, brings hither a great resort of people; and as many of the inhabitants are persons of fashion, they are well bred, gay, and sociable. The duc de Villars, who is governor of the province, resides on the spot, and keeps an open assembly, where strangers are admitted without reserve, and made very welcome, if they will engage in play, which is the sole occupation of the whole company. Some of our English people complain, that when they were presented to him, they met with a very cold reception. The French, as well as other foreigners, have no idea of a man of family and fashion, without the title of duke, count, marquis, or lord, and where an English gentleman is introduced by the simple expression of monsieur tel, Mr. Suchathing, they think he is some plebeian, unworthy of any particular attention.

Aix is situated in a bottom, almost surrounded by hills, which, however, do not screen it from the Bize, or north wind, that blows extremely sharp in the winter and spring, rendering the air almost insupportably cold, and very dangerous to those who have some kinds of pulmonary complaints, such as tubercules, abscesses, or spitting of blood. Lord H - , who passed part of last winter in this place, afflicted with some of these symptoms, grew worse every day while he continued at Aix: but, he no sooner removed to Marseilles, than all his complaints abated; such a difference there is in the air of these two places, though the distance between them does not exceed ten or twelve miles. But the air of Marseilles, though much more mild than that of Aix in the winter is not near so warm as the climate of Nice, where we find in plenty such flowers, fruit, and vegetables, even in the severest season, as will not grow and ripen, either at Marseilles or Toulon.

If the air of Aix is disagreeably cold in the winter, it is rendered quite insufferable in the summer, from excessive heat, occasioned by the reflexion from the rocks and mountains, which at the same time obstruct the circulation of air: for it must be observed, that the same mountains which serve as funnels and canals, to collect and discharge the keen blasts of winter, will provide screens to intercept intirely the faint breezes of summer. Aix, though pretty well provided with butcher's meat, is very ill supplied with potherbs; and they have no poultry but what comes at a vast distance from the Lionnois. They say their want of roots, cabbage, cauliflower, etc. is owing to a scarcity of water: but the truth is, they are very bad gardeners. Their oil is good and cheap: their wine is indifferent: but their chief care seems employed on the culture of silk, the staple of Provence, which is every where shaded with plantations of mulberry trees, for the nourishment of the worms. Notwithstanding the boasted cheapness of every article of housekeeping, in the south of France, I am persuaded a family may live for less money at York, Durham, Hereford, and in many other cities of England than at Aix in Provence; keep a more plentiful table; and be much more comfortably situated in all respects. I found lodging and provision at Aix fifty per cent dearer than at Montpellier, which is counted the dearest place in Languedoc.

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.

Having ordered our coach to be refitted, and provided with fresh horses, as well as with another postilion, in consequence of which improvements, I payed at the rate of a loui'dore per diem to Lyons and back again, we departed from Aix, and the second day of our journey passing the Durance in a boat, lay at Avignon. This river, the Druentia of the antients, is a considerable stream, extremely rapid, which descends from the mountains, and discharges itself in the Rhone. After violent rains it extends its channel, so as to be impassable, and often overflows the country to a great extent. In the middle of a plain, betwixt Orgon and this river, we met the coach in which we had travelled eighteen months before, from Lyons to Montpellier, conducted by our old driver Joseph, who no sooner recognized my servant at a distance, by his musquetoon, than he came running towards our carriage, and seizing my hand, even shed tears of joy. Joseph had been travelling through Spain, and was so imbrowned by the sun, that he might have passed for an Iroquois. I was much pleased with the marks of gratitude which the poor fellow expressed towards his benefactors. He had some private conversation with our voiturier, whose name was Claude, to whom he gave such a favourable character of us, as in all probability induced him to be wonderfully obliging during the whole journey.

You know Avignon is a large city belonging to the pope. It was the Avenio Cavarum of the antients, and changed masters several times, belonging successively to the Romans, Burgundians, Franks, the kingdom of Arles, the counts of Provence, and the sovereigns of Naples. It was sold in the fourteenth century, by queen Jane I. of Naples, to Pope Clement VI. for the sum of eighty thousand florins, and since that period has continued under the dominion of the see of Rome. Not but that when the duc de Crequi, the French ambassador, was insulted at Rome in the year 1662, the parliament of Provence passed an arret, declaring the city of Avignon, and the county Venaiss in part of the ancient domain of Provence; and therefore reunited it to the crown of France, which accordingly took possession; though it was afterwards restored to the Roman see at the peace of Pisa. The pope, however, holds it by a precarious title, at the mercy of the French king, who may one day be induced to resume it, upon payment of the original purchase-money. As a succession of popes resided here for the space of seventy years, the city could not fail to be adorned with a great number of magnificent churches and convents, which are richly embellished with painting, sculpture, shrines, reliques, and tombs. Among the last, is that of the celebrated Laura, whom Petrarch has immortalized by his poetry, and for whom Francis I. of France took the trouble to write an epitaph. Avignon is governed by a vice-legate from the pope, and the police of the city is regulated by the consuls.

It is a large place, situated in a fruitful plain, surrounded by high walls built of hewn stone, which on the west side are washed by the Rhone. Here was a noble bridge over the river, but it is now in ruins. On the other side, a branch of the Sorgue runs through part of the city. This is the river anciently called Sulga, formed by the famous fountain of Vaucluse in this neighbourhood, where the poet Petrarch resided. It is a charming transparent stream, abounding with excellent trout and craw-fish. We passed over it on a stone bridge, in our way to Orange, the Arausio Cavarum of the Romans, still distinguished by some noble monuments of antiquity. These consist of a circus, an aqueduct, a temple, and a triumphal arch, which last was erected in honour of Caius Marius, and Luctatius Catulus, after the great victory they obtained in this country over the Cimbri and Teutones. It is a very magnificent edifice, adorned on all sides with trophies and battles in basso relievo. The ornaments of the architecture, and the sculpture, are wonderfully elegant for the time in which it was erected; and the whole is surprisingly well preserved, considering its great antiquity. It seems to me to be as entire and perfect as the arch of Septimius Severus at Rome. Next day we passed two very impetuous streams, the Drome and the Isere. The first, which very much resembles the Var, we forded: but the Isere we crossed in a boat, which as well as that upon the Durance, is managed by the traille, a moveable or running pulley, on a rope stretched between two wooden machines erected on the opposite sides of the river. The contrivance is simple and effectual, and the passage equally safe and expeditious. The boatman has nothing to do, but by means of a long massy rudder, to keep the head obliquely to the stream, the force of which pushes the boat along, the block to which it is fixed sliding upon the rope from one side to the other. All these rivers take their rise from the mountains, which are continued through Provence and Dauphine, and fall into the Rhone: and all of them, when swelled by sudden rains, overflow the flat country. Although Dauphine affords little or no oil, it produces excellent wines, particularly those of Hermitage and Cote-roti. The first of these is sold on the spot for three livres the bottle, and the other for two. The country likewise yields a considerable quantity of corn, and a good deal of grass. It is well watered with streams, and agreeably shaded with wood. The weather was pleasant, and we had a continued song of nightingales from Aix to Fontainebleau.

I cannot pretend to specify the antiquities of Vienne, antiently called Vienna Allobrogum. It was a Roman colony, and a considerable city, which the antients spared no pains and expence to embellish. It is still a large town, standing among several hills on the banks of the Rhone, though all its former splendor is eclipsed, its commerce decayed, and most of its antiquities are buried in ruins. The church of Notre Dame de la Vie was undoubtedly a temple. On the left of the road, as you enter it, by the gate of Avignon, there is a handsome obelisk, or rather pyramid, about thirty feet high, raised upon a vault supported by four pillars of the Tuscan order. It is certainly a Roman work, and Montfaucon supposes it to be a tomb, as he perceived an oblong stone jetting out from the middle of the vault, in which the ashes of the defunct were probably contained. The story of Pontius Pilate, who is said to have ended his days in this place, is a fable. On the seventh day of our journey from Aix, we arrived at Lyons, where I shall take my leave of you for the present, being with great truth - Yours, etc.