MARRANA, A.D. 1124, AND THE
RIVER ALMO.

These three may all be treated as one aqueduct for the supply of Rome, partly natural and partly artificial. They all come from the Alban Hills; the first from near Rocca di Papa on very high ground, the second from about a mile above the small and very picturesque town of Marino; the third lower down the same hill. They are all mountain streams, and partake of the usual character of such streams; in dry weather the springs that supply the Almo bring so little water, that it is only sufficient to fill some ponds for cattle at the foot of the hill. The deep bed of the river, which winds about the Campagna for miles, is therefore dry for a great part of the year, but the other two streams never fail; they are united at the foot of the hill, not far from the place where the Aqua Aurelia came from. The greater part of their united waters runs into the river Anio, but a portion of it is diverted near the ruins of the ancient fortified village or pagus, called Centroni (2315,2316, 2317,2318, 2319), on the road to Tusculum, (now Frascati,) about eight miles from Rome. This branch to supply Rome is first brought through an ancient tunnel of the Aqua Julia, at each end of which remains can be seen of the stone specus and the flood-gates (2310, 2311, 2312, 2313). The water is then conveyed in a bank of clay for about a mile, and then in the bed of one of the many branches of the mountain stream called the river Almo, and so brought into Rome (1309, 1318), under the Porta Metronia, which is built upon a bridge over it. The stream passes under some other bridges with mills upon them, and eventually falls into the Tiber through an aperture left for

it in the Pulchrum Littus, or fine tufa wall of the Kings (drawing, 1235; plans, 368*, 1234*; views, 77, 166, 157).

Another branch from it is carried from the junction or separation between the Torre Fiscale and Roma Vecchia (1937*) by the side of the cross road from the Via Appia Nova to the Via Appia Antiqua. Sometimes in the bed of the Almo, and in other parts, where the ground is low and the stream is liable to floods, an artificial canal is made for it, which may be seen in the valley of the Caffarella. This excellent plan was carried out in the most economical but effectual manner by a company in the twelfth century. This is really an aqueduct, though not usually so called; it is kept in repair by the present Water-Company, and is of great importance for Rome; as the floods to which the Almo was always liable along its whole line, and within the walls of Rome, (as is mentioned by Cicero,) are effectually kept out of Rome, and a constant, regular supply of water is obtained.

XVIII. AQUA FELICE, made A. D. 1587 by Pope Sixtus V. (Felice Peretti).

The sources of it are the springs under the hill on which La Colonna stands. The same water had been used long before, and brought into Rome by the aqueduct (XI.) of Hadrian and Trajan before mentioned. The large reservoir for the water now in use is very near to the remains of the old one of Hadrian. The construction of this aqueduct is very rude and rough, of concrete and rubble-stone only, and this stone consists entirely of old materials; still the large scale of the work, and the height at which the specus is carried upon the arcade, give it a grand effect. At a little distance, the inferior construc

tion is not seen, and this almost modern aqueduct is frequently mistaken by strangers for one of the old ones of the time of the Empire, of which it is only an imitation. It is seen in several of the views of the older aqueducts in the Campagna, especially those at the Torre Fiscale (531, 1028, 1029) and the Porta Furba (68, 1437). Here it crosses the road to Frascati on an arch, with an inscription upon it. In the latter part of its course it is made on the piers of the Claudian arcade, and it enters Rome at the same point, the north-east corner of the gardens of S. Croce. After passing along the north side of them, it is divided into different branches by a reservoir at the angle, close to the south side of the Porta Maggiore (30). The principal stream then passes along upon the Wall of Aurelian (80 a, b, 81), on the same high bank as the earlier aqueducts had done; it was cut through in making the railway, but a new bridge over that road was built for it (29). Near this it can be seen that it is carried on the piers of an older aqueduct for some distance (28). See Alexandrina (XV.) Further on towards the Porta di S.

Lorenzo the ground is higher, and in order to keep the level necessary for the specus, it is brought within the wall, and built up against the inside of it (1871). The Marcia, Tepula, and Julia, over which it is carried, as is seen at the two gates where their arcade is visible under the specus of the Aqua Felice, are here still under it, but underground also, owing to

the higher level of the ground. It passes over the Porta di S. Lorenzo to a reservoir on the north side of it, and then turns to the west by the side of the road, which it crosses upon an arch, with an inscription upon it, at a short distance within that gate (81). The principal termination of it is at the Fountain of the Termini (called of Moses,) 71. Behind the fountain is a reservoir after the old fashion, which is illustrated by a plan and section (704*). The celebrated Fountain of the Triton (1196), in the Piazza Barberini, is also supplied by this aqueduct, as well as all the upper terraces upon the hills. The lower range, on the Campus Martius, is chiefly supplied by the Virgo. Another branch goes from the reservoir at the Porta Maggiore along the bank on which the Arches of Nero are carried, to the Lateran, where the fountains are supplied by this water. The old aqueduct was used according to the custom of the time, and there is a cascade specus from the level of the Marcia to that of the Appia (shewn in 541).

The specus of each of these old aqueducts was used to carry the metal pipes of the Aqua Felice, when it was convenient to do so (1295*), as has been previously mentioned.

THE AQUA MARCIA PIA was made by a Company between 1860 and 1870, and has been mentioned under the head of the Marcia (a part of it is shewn in 1553).