On the left, where the Via Appia crosses the brook of the Almo, now called Maranna, the Via di San Sisto Vecchio leads to the back of the Cœlian behind S. Stefano Rotondo. Here, in the hollow, in the grounds of the Villa Mattei, under some picturesque farm-buildings, is a spring which modern archæology has determined to be the true _Fountain of Egeria_, where Numa Pompilius is described as having his mysterious meetings with the nymph Egeria. The locality of this fountain was verified when that of the Porta Capena was ascertained, as it was certain that it was in the immediate neighbourhood of that gate, from a passage in the 3d Satire of Juvenal, which describes, that when he was waiting at the Porta Capena with Umbritius while the waggon was loading for his departure to Cumæ, they rambled into the valley of Egeria, and Umbritius said, after speaking of his motives for leaving Rome, "I could add other reasons to these, but my beasts summon me to move on, and the sun is setting. I must be going, for the muleteer has long been summoning me by the cracking of his whip." To this valley the oppressed race of the Jews was confined by Domitian, their furniture consisting of a basket and a wisp of hay: "Nunc sacri fontis nemus et delubra locantur Judæis, quorum cophinus fœnumque supellex." _Juvenal, Sat._ iii. 13. On the right, are the _Baths of Caracalla_, the largest mass of ruins in Rome, except the Coliseum; consisting for the most part of huge shapeless walls of red and orange-coloured brickwork, framing vast strips of blue sky, and tufted with shrubs and flowers. These baths, which could accommodate 1600 bathers at once, were begun in A.D. 212, by Caracalla, continued by Heliogabalus, and finished under Alexander Severus. They covered a space of 2,625,000 square yards--a size which made Ammianus Marcellinus say that the Roman baths were like provinces--and they were supplied with water by the Antonine Aqueduct, which was brought hither for that especial purpose from the Claudian, over the Arch of Drusus. Antiquaries have amused themselves by identifying different chambers, to which, with considerable uncertainty, the names of Calidarium, Laconicum, Tepidarium, Frigidarium, &c., have been affixed. The habits of luxury and inertion which were introduced with the magnificent baths of the emperors were among the principal causes of the decline and fall of Rome. Thousands of the Roman youth frittered away their hours in these magnificent halls, which were provided with everything which could gratify the senses. Poets were wont to recite their verses to those who were reclining in the baths. ----"In medio qui Scripta foro recitent, sunt multi,--quique lavantes: Suave locus voci resonat conclusus." _Horace, Sat._ i. 4.