EXPLORATIONS IN ROMR. 251 lioles for the beams of the old floor, which still remain in the walls of some of the I'ooms. The subten-anean passa<'-e lias a drain under it, which is in some parts under the pave- ment ; this drain had been choked up by neglect, and a part of the passai^e itself had thus become a drain. Tiiis was traced by the persons employed passing along under tiie Forum Komanum, and eventually into the Cloaca Maxima. The history of this prison is well known, and the account of the imprisonment of Jugurtha in it as related by Sallust has been noticed on previous occasions. The exist- ence of a far greater part of this ancient prison, much more than was previously supposed, is now clearly proved, althou-di many were quite incredulous about it. The other work on which we were previously engaged was the Porticus of the Thei-nuT of Antoninus Cai-acalla, often called the Thermal of the Antonines. This Porticus or arcade completed the great work of the Therma?, and was between the main building and the Via Appia ; probably it faced that street, and ran down one side of it. The line of the street or road has been slightly changed in that part, and it is probable that it ran along in front of the Porticus, where we have found remains of an old paved street, with the raised footpaths, called crcpedines, on each side of it, and slight remains of a temple on the other side, which passes under the present Church of SS. Nereus and Achilleus. Our explorations in that direction were again stopped by water. At the south end of the Porticus, between that and the main buihling of the Therma), we had ascertained in previous years that the ground had been intentionally raised as much as 30 ft. against the back wall of the Porticus (on the top of which wall are remains of an aqueduct), and the great main building. In this made earth, at the south end of the vineyard of Mr. Brocard, we had also found painted chambers, at the depth of 30 ft. from the surface of the ground in that part ; but as the ground in front of the Porticus is 20 ft. below the level of what it is at the back, tiie paved street in front of it would correspoml in level with the building, to which these painted chambers belongeil. This buihling I had for some time conjectured to have been the Palace of the Emperor Hadrian, called in the Regionary Catalogue of the fourth century, Privata Iladriaua,
