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ANNUAL REGISTER For the YEAR 1772.

time to have thrown down that part of the cone next the sea, which would naturally have left it in its present state, and that the conical mountain, or existing Vesuvius, has been raised by the succeeding eruptions: all my observations confirm this opinion. I have seen ancient lavas in the plain on the other side of Somma, which could never have proceeded from the present Vesuvius. Serao, a celebrated physician now living at Naples, in the introduction of his account of the eruption of Vesuvius in 1737, (in which account many of the phænomena of the volcano are recorded and very well accounted for) says, that at the convent of Dominican fryars, called the Madona del Arco, some years ago, in sinking a well, at a hundred feet depth, a lava was discovered, and soon after another, so that in less than three hundred feet depth, the lavas of four eruptions were found. From the situation of this convent it is clear beyond a doubt, that these lavas proceeded from the mountain called Somma, as they are quite out of the reach of the existing volcano.
From these circumstances and from repeated observations I have made in the neighbourhood of Vesuvius, I am sure that no virgin soil is to be found there, and that all is composed of different strata of erupted matter, even to a great depth below the level of the sea. In short, I have not any doubt in my own mind, but that this volcano took its rise from the bottom of the sea; and as the whole plain between Vesuvius and the mountains behind Caserta, which is the best part of the Campagna Felice, is (under its good soil) composed of burnt matter, I imagine the sea to have washed the feet of those mountains, until the subterraneous fires began to operate, at a period certainly of a most remote antiquity.
The soil of the Campagna Felice is very fertile; I saw the earth opened in many places last year in the midst of that plain, when they were seeking for materials to mend the road from Naples to Caserta. The stratum of good soil was in general four or five feet thick; under which was a deep stratum of cinders, pumice, fragments of lava and such burnt matter as abounds near Vesuvius and all volcanos. The mountains at the back of Caserta are mostly of a sort of limestone, and very different from those formed by fire; though Signior Van Vitelli, the celebrated architect, has assured me, that in the cutting of the famous aqueduct of Caserta through these mountains, he met with some soils, that had been evidently formed by subterraneous fires. The high grounds which extend from Castel-a-Mare to the point of Minerva towards the island of Caprea, and from the promontory that divides the bay of Naples from that of Salerno, are of lime-stone. The plain of Sorrento, that is bounded by these high grounds, beginning at the village of Vico, and ending at that of Massa, is wholly composed of the same sort of tufa as that about Naples, except that the cinder or pumice stones intermixed in it are larger than in the Naples tufa. I conceive then that there has been an explosion in this spot from the bottom of the sea. This plain, as I have remarked to be the case with all soils produced by subterraneous fire, is extremely fertile; whilst 
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the ground about it, being of another nature, is not so. The island of Caprea does not shew any signs of having been formed by subterraneous fire, but is of the same nature as the high grounds last mentioned, from which it has been probably detached by earthquakes, or the violence of the waves. Rovigliano, an island, or rather a rock in the bay of Castel-a-Mare, is likewise of lime-stone, and seems to have belonged to the original mountains in its neighbourhood: in some of these mountains there are also petrified fish and fossil shells, which I never have found in the mountains, which I suppose to have been formed by explosion. 
You have now, Sir, before you the nature of the soil, from Caprea to Naples. The soil on which this great metropolis stands has been evidently produced by explosions, some of which seem to have been upon the very spot on which this city is built; all the high grounds round Naples, Pausilipo, Puzzole, Baia, Misenum, the islands of Pro-cita and Ischia, all appear to have been raised by explosion. You can trace still in many of these heights the conical shape that was naturally given them at first, and even the craters out of which the matter issued, though to be sure others of these heights have suffered such changes by the hand of time, that you can only conjecture that they were raised in the like manner, by their composition being exactly the same as that of those mountains, which still retain their conical form and craters entire. A tufa, exactly resembling the specimen I took from inside of the theatre of Herculaneum, layers of pumice intermixed with layers of good soil, just like those over Pompeii, and lavas like those of Vesuvius, compose the whole soil of the country that remains to be described.
The famous grotto anciently cut through the mountain of Pausilipo, to make a road from Naples to Puzzole, gives you an opportunity of seeing that the whole of that mountain is tufa. The first evident crater you meet with, after you have passed the grotto of Pausilipo, is now the lake of Agnano; a small remain of the subterraneous fire (which must probably have made the bason for the lake, and raised the high grounds which form a sort of amphitheatre round it) serves to heat rooms, which the Neapolitans make great use of in summer, for carrying off diverse disorders, by a strong perspiration. This place is called the Sudatorio di San Germano; near the present bagnios, which are but poor little hovels, there are the ruins of a magnificent ancient bath. About an hundred paces from hence is the Grotto del Cane; I shall only mention, as a further proof of the probability that the lake of Agnano was a volcano, that vapours of a pernicious quality, as that in the Grotto del Cane, are frequently met with in the neighbourhood of Etna and Vesuvius, particularly at the time of, before, and after great eruptions. The noxious vapours having continued in the same force constantly so many ages, as it has done in the Grotto del Cane (for Pliny mentions this grotto), is indeed a circumstance in which it differs from the vapours near Vesuvius and Etna, which are not constant; the cone forming the outside of this supposed volcano is still perfect in many parts.
F 3 Oppo- 

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