Junctions of the arcade of Sixtus V., or Aqua Felice, with that of the Claudia, take place at an angle where the Torre Fiscale has been built, and again at another angle where there is an archway called the Porta Furba, about two miles from Rome, and a most picturesque ruin of a _piscina_, with a tall tower by the side of it, in which is the ventilating-shaft of the conduit. The difference of construction and of level is very evident, and the three conduits carried on the same arches may be seen distinctly. The construction of the Claudia (VIII.) is of large square blocks of stone. The Anio Novus (IX.) is merely an additional brick conduit, the work is part of that of Claudius and Nero, and is carried over the original one at a great height from the ground. Near the city only small portions of this upper conduit remain here and there, as, for instance, over the Porta Maggiore, and in a few places on the wall. In some places, the arcade of the Aqua Felice runs parallel to the Claudian for a considerable distance, and is joined to it at both ends, as near the Porta Furba. This lower arcade carried part of the conduits of the Aqua Marcia, Tepula, and Julia, which ran from the Porta Furba into the city parallel to the later one of Claudius, at a lower level. Where the Aqua Felice enters the city, it is carried on the piers of the arcade of Claudius, from the junction with the arches of Nero, over the Porta Maggiore to the old _castellum_ at the corner of the wall, where it turns at a sharp angle. Here the arches of Claudius cease; but the conduit of the Aqua Felice is continued along the city wall, of which it forms part, upon the ancient embankment as far as the Porta S. Lorenzo, and over the archway of Augustus there, using one of the older conduits. It then makes a sharp turn to the west, and after being carried along the north side of the road for a short distance, crosses it again on an archway built for the purpose by Sixtus V., as recorded by an inscription upon it; then it turns sharply to the west again, and is carried on an arcade between the road on the north and the railway on the south, to the great inner _agger_, which it reaches at a point near the Thermæ of Diocletian and the railway station. It is then carried in an old _specus_ in that bank along the east side of the Thermæ, and turns at an angle to the north, at the Via Nomentana, near the Porta Nomentana, a little to the south of the modern Via di Porta Pia; then along the north side of the Thermæ till it arrives at the great reservoir behind the fountain of Termini. The _specus_ is three feet wide, and the water in it is usually from three to four feet deep, running with a rapid current about five miles an hour, and constantly flowing day and night. Thence it is carried in pipes to the different reservoirs and fountains of the upper town. It also supplies the lower part of the city from the Ghetto to the Marmorata, along the bank of the Tiber. SUMMARY.