PLATE XVII.

ARCHES OF NERO WITHIN THE PORTA MAGGIORE.

THIS double arcade crosses the valley or inner foss of the Sessorian Palace. It was built on this plan for greater strength, as the piers are of a great height. This arcade is a continuation of the one that forms the northern wall of the Sessorian gardens, in a direct line to the west, over the Coelian to the great reservoir over the Arch of Dolabella (shewn in the last plate). The specus was carried at the top, and conveyed the water of the Claudian and Anio Novus, united at the Gemelli (a great twin reservoir which was close to that point, and at the north-west angle of the Sessorian gardens). The Claudian as a separate water turns at a sharp angle, and goes on to the Porta Maggiore, with the Anio Novus over it, and terminated at another tower just to the north of the place where the Marcia, Tepula, and Julia pass through the wall. But they left a considerable part of their water at that angle to be united to that of the Anio Novus at the Gemelli.

The lower view represents a fragment of the Aqua Marcia, as repaired and restored by Trajan, to the north of, and near the Porta Maggiore, in the vineyard in which the Minerva Medica stands, which has been the Exquiliæ, and afterwards the gardens of Mæcenas. This, which is parallel to the City wall, is joined to it a little further on. It was accidentally brought to light by some excavations in 1871, and is now buried again.

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PLATE XVIII.

THE CLAUDIAN AND THE ANIO NOVUS, IN THE North Wall of THE SESSORIAN GARDENS, NEAR THE PORTA MAGGIORE.

THE wall for about a quarter of a mile is entirely made out of this arcade, with the arches filled up, but it is built upon the old earthwork of the Sessorium, probably of the time of the Kings. The arcade extends from the angle at the north-east corner, where the aqueduct entered Rome, to the north-west angle near the Porta Maggiore, which was called Porta Sessoriana, because it entered into the Sessorian gardens.

The lower view represents the NYMPHÆUM OF ALEXANDER SeveRUS, WHERE THE TROPHIES OF MARIUS WERE HUNG.

This is identified by a representation of it on one of the coins of that Emperor. It is commonly miscalled a Castellum of the Aqua Julia, but it is on too high a level for that water, and there is no other but the Anio Novus which is high enough; this was brought along the wall to another reservoir near the Porta Tiburtina, and then by a branch arcade to this point, where there is another large reservoir on high ground, from which the water was dispersed in different directions. One branch went to supply the great reservoir called the Sette Sale, which supplied the Thermæ of Titus and Trajan on the Exquiliæ, and from thence went on to the Colosseum and to the Tiber. Another branch supplied the Thermæ of Constantine, on the Quirinal.

PLATE XIX.

RESERVOIR ON THE ARCHES OF NERO OVER THE ARCH
OF DOLABELLA.

THIS Plate is almost a repetition of Plate XV., but from a different point of view, and this great reservoir is of so much importance for the history of the aqueducts in Rome, that it was necessary to shew it as clearly as possible. Without repeating what has been said before, we may add that the arch seen to the right in this view is the beginning of an arcade which led to the Colosseum. Another branch in a more direct line led to the Palatine, after passing first along the north wall of the garden of the Villa Celimontana, then by the western side of the Clivus Scauri, parallel to the church of SS. John and Paul, and at the foot of the hill passing across the road, and under the apse of the church; then turning again southwards on an arcade across the valley to the Palatine, of which there are remains; afterwards passing along the whole length of the Palatine underground, it is visible at the mouth of a tunnel on the platform opposite to the Capitoline Hill, and went across the Forum Romanum over the bridge of Caligula. The work of Nero stopped at the Arch of Dolabella, but it was taken up and completed by his successors.

Another branch went also to the left, on the west wall of the garden of the Villa Celimontana, to the valley between the Coelian and the Aventine. There is a large reservoir for it on the cliff of the Cœlian, partly below and partly above it, and in the garden of the monks of S. Gregory. It then went on a tall arcade, over the Porta Capena and the agger of Servius Tullius, to the Piscina Publica, and from thence, again crossing the valley between the two parts of the Aventine, to the Therma of Sura, and the private house of Trajan, and the temples on the edge of the Aventine, and to the mouth of the aqueducts in the cave under the Priorato at the Porta Trigemina, and so to the Tiber.