A ridge of hills raised about 300 or 400 feet above the level of the sea, stretch in a direction parallel to the coast, from the Tiber to Torre St Lorenzo, beyond Ar dea. The tongue of land which lies between this range and the sea is entirely formed by the allu don of the Ti ber and of the sea, which throws back upon the land the sand which is carried down by the river. The whole of the country, which was the ancient Laurentum, is ex tremely fertile, and the climate very temperate.
Though different travellers hate pointed out craters in various parts of the Campagna, yet there appear to be only three which are characterised with sufficient distinctness. The first of these is the famous lake Rc gillus, which is about a quarter of a league in diameter. It is placed at the bottom or an inverted cone of hard black lava, from forty to sixty feet high, which forms bare and rugged rocks, and is entirely open on the side of the road where the lake is level w ith tie plain. This crater is not like those of Albano and Nemi, covered with volcanic ejections which take away from it the re gula• form of an inverted cone; but the lava is almost completely uncut ered in its upper part.
The two other craters or Atha.. and Nemi are about four or fiNe hundred feet higner than that of lake Re gillus. They are covered with volcanic ejections seve ral hundred feet in height, which prolong the cone front the hard lava which forms the basins of the Likes. These two craters are of a Very regular conical form, and so extremely high that it requires half an hour to ascend front the lake to the top of the higher cone. The fa mous emissary made at the siege of Vcii, is cut pre cisely between the volcanic ejections, which are easily pierced, and the hard lava which now contains the re maining waters of the lake. When the lake occupied the higher part of its extensive basin, the immense mass of waters which it contained were in danger of over whelming the rich plains below. The wealthy citizens of Rome, alarmed for the destruction of their ficids, are said to have made use of the siege of Vcii as a pretext for the people, or a part of the army, to cut the emissary, by which the superabundant water was dis charged." The crater of Nemi is a very little smaller than that of Albano, but is equally regular and pictu resque. Its cone does not appear to have been at any
time entirely filled with the water of the lake. The lava in the Campagna is every where of an unilorm hardness and appearance ; and wherever it appears, it is coveted with volcanic ejections.
There are numerous sulphureous springs in the Cam pagna, but the most abundant of these is between Tivoli and Rome, where the water conies out of the ground almost boiling hot, and forms the lake of Solfatara. The reeds and other vegetables are so incrusted with calcareous depositions, that they have the appearance of stone, and islands of a considerable size, which are form d by them, float about the lake, and are capable of car • several people at a time. The stream issuing 's lake has the same property, and continues to slitoko it joins the Anio or the Teverone. The Anio possesses . ..milar property of forming calcareous de positions of eve y shade, From the brilliant crystallisa tions, which arc called confetti di Tivoli, to the darker concretions, which have incrusted a very near Rome. Near Subiaco the minutest inst cts, and the leaves of the vine, are distinctly seen in these incrusta tions. After the Anio has passed the fine cascades of Tivoli, it fat ms, by depositions in the great plain, those immense beds of travertino, of which St Peter's, a part of the Collisetun, and all the other public edifices in Rome aie built. There are likewise several springs of acidulous water without any sulphur, as at Aqua Ace tosa.
The Campagna contains 112,909 rubbias (a rubbia of land contains 4866 square toises) or 940 square miles, or 7 t to a degree. About two fifths of this land belongs to the church, and the other three fifths to about a hun dred lay proprietors. The farms are held by leases of nine years, and also by perpetual leases ; hut the last of these leases is abrogated, lithe farmer neglects for two years to pay his rent. The general price of a rubbia of good land is abort twenty piastres, and the expense of cultivating it amounts to about forty piastres.
Before the revolution, a rubbia of corn was sold at six or eight piastres ; hut in the year 1802, the price varied from 22 to 30 piastres.