The lake of Agnano is a pretty little circular piece of water, more varied in its banks than the volcanic lakes about Rome. It abounds in wild fowl, but is said to be destitute of fish. There are some remains of ancient baths, which have been rudely fitted up for modern use, under the name of Stufe di San Germano, a _stufa_ being a steaming place, as opposed to a bath where you enter the water. A hot sulphureous vapour issues from the rock, which is supposed in many cases to be very conducive to health. After walking about 100 yards by the side of the lake, where the ground was covered with frogs three deep, on which it was impossible to avoid treading, we arrived at the Grotto del Cane. I had refused the dog, but I suppose he does not suffer greatly, since he accompanied us of his own accord to the mouth of the grotto. This is merely a little hollow in the side of the hill, hardly deserving the name of a cave, but fastened with a door for fear of accidents. I could hardly stand upright in it. A warm vapour rises about eighteen inches from the ground, which extinguishes a torch instantly. From this I walked back to Naples, being already nearly two miles on the road, but I shall here add the account of some farther excursions, in one of which I engaged the corribolo from Naples, as far as the Arco Felice. We pass under what is called the Villa of Cicero, at a small distance from Pozzuoli. It only consists of rubble walls, partially faced with reticulated tufo, and is certainly misnamed. We pass behind Monte Nuovo, which as all the world knows, rose in one night. The present height is 460 feet, but it appears at first to have been considerably greater. The old crater is covered with herbage, but there is one spot on the outside where the ground is still warm. Beyond this hill we look down to the left on the lake of Avernus, no longer a pestiferous lake which birds cannot fly over; but as it is evidently one of the volcanic craters with which this country abounded, one knows not what formerly may have been the case. Although looking down upon one crater, we still seem inclosed in a larger one, whose circuit is penetrated by the Arco Felice. This is pretended to have been part of the circumference of the ancient Cuma, but it is a Roman work formed of rubble-work faced with brick, wherever it is not part of the natural rock.