fine arches of the Neronian branch from the Claudian Aqueduct erected almost over it. It is very probable that one of the laws (referred to by Frontinus as having been in existence long before his time) respecting aqueducts was in force from the commencement, namely, that there should be no buildings of any kind within ten feet on either side of the aqueducts; thus an open space was probably existing at the time when Nero wished to carry water to his magnificent reservoir at the north-western end of the Coelian, and of this he availed himself in rearing the splendid arcade which is called by his name. It will be remarked, however, that the brick buttresses actually came down to the flat roof of the original specus of the Appian. The top of that specus was raised to a greater height by the engineers of Sixtus V., and in this enlargement the underground supports of the Neronian arches are cut through to give headway to the aquarii passing along the channel. They have however to stoop their heads as they pass under each buttress.

The old tunnel specus was discovered in the time of Sixtus V., (Felice Peretti), filled up by clay deposit to the depth of three feet, or half the height of the specus, as in other places, and the builders found it easier to raise it, for the aquarii to go along it, than to clear it out. They therefore knocked away the flat tilecovering of the time of Nero, and raised a vault of rubble-stone three feet higher.

From the great subterranean reservoir, still in use for the water of a spring, near the Arch of Dolabella, to the edge of the western cliff of the Coelian is but a short distance, and here the specus seems to run in a bank dividing the vineyard or garden of the Villa Mattei from that of the monks of S. Gregory, on which a wall has been built. At this point subsequent alterations, and especially those under the Emperors Nerva and Trajan, have buried to a great depth the actual remains of the original aqueduct; but this later work occupies the same line, and must be described. We first come to a large piscina or filtering-place on the cliff of the Cœlian, immediately above the Porta Capena. This piscina is divided into two parts, one above the other; but both are below the top of the cliff, and are faced with brick and reticulated work of the time of Trajan. There are remains of two specus running along against the face of the cliff; of the upper one the lower part, or pavement, of Opus Signinum, only remains, and this runs down in a sloping direction from the upper reservoir to a lower one, a little to the south of it, which is very extensive. This lower reservoir consists of several parallel

chambers, through which, or rather in front of which, another specus runs at a lower level; this appears to be horizontal. This specus goes on in the direction of the ruins of a building of various periods, possibly the remains of the Ædes Camenarum, and passes then to the south in the direction of the Thermæ of Severus and Commodus. Another branch was evidently afterwards made from the upper reservoir going towards the north for a very short distance, merely for one of the usual angles; then, turning again to the west, in the valley below, there is another large castellum aquæ, or reservoir of five chambers, all as usual oblong and side by side. This is on lower ground, and is built upon the wall of Servius Tullius, where it crosses the valley; the upper part of this reservoir has been made into a house for the gardener. The underground part of the chamber nearest to the Cœlian is built of the large square blocks of tufa usual in the time of the Kings, and belongs to the fortifications of the Porta Capena, over the Via Appia, which here passed close under the Cœlian; the other chambers appear, from the bricks, to be of the time of Trajan. From this point to the Piscina Publica, the line of tall brick piers of Trajan can be distinctly traced by the existing remains, passing across to the other side of the road and of the stream here close to it. The ruins of the Piscina Publica, as rebuilt by Trajan, remain visible under the corner of the Pseudo-Aventine, near S. Balbina, and from this the water was again distributed in different branches. At this point, let it be observed, and only at this point, is the valley which divides the Coelian from the Aventine sufficiently narrow to admit of agreement with the direct and clear assertion of Frontinus, that here alone, throughout the whole course, was it carried on a substructure and on arches for a dis-. tance of one hundred yards.

Although there are no remains of the specus now visible at this spot, because the gate has been destroyed, there can be little doubt that the channel for the water was carried over the southern gate of the city according to its extent at that time. This gate was called the Porta Capena; and as the Appian aqueduct was allowed to fall into decay, it gave rise to the descriptions both of Martial and Juvenal, who describe it as wet or moist'.

This is on the line of the wall of Servius Tullius. It appears that Trajan made a reservoir here over the old one. The specus of the Appia passes through the present gardener's house lengthwise, from east to west. This specus was found again in another excavation to

the west of it, by the side of the present road.

r

66

"Substitit ad veteres arcus madidamque Capenam." (Juvenal, sat. iii. ver. 11.) Capena grandi porta qua pluit gutta." (Martial, lib. iii. epigr.47.) The distance from the foot of the Cœlian

The excavations made in 1868 and 1869 under the direction of Mr. Parker, with the help of the British Archæological Society of Rome and the Roman Exploration Fund, have clearly shewn the specus of the Aqua Appia and those of two other aqueducts carried upon the agger of Servius Tullius across the valley from the Cœlian to the Aventine, with branches to the left running into the subterranean chambers of the Piscina Publica. These underground chambers are of the time of the Republic, the walls are built of rubble stone as usual at that period, and there are small openings through these walls for the circulation of the water, although the upper part has been rebuilt in the time of Trajan, as the remains of the wall are faced with the brickwork usual in his time. The lowest specus is cut out of tufa rock under the wall of Servius Tullius, which is built of the usual large blocks of tufa.

The principal branch went underground to the cave reservoir at its mouth, on the level of the quay of the Marmorata between that and the Salaria, just outside of the old Porta Trigemina; the old agger in which that gate was situated still forms the southern or lower boundary of the wharf of the Salaria. Part of the course of this earliest specus, that of the Appia, can be traced and seen in a subterranean stone quarry nearly under S. Sabba. The specus is six feet high and two feet wide, and it is filled up to nearly half its height by solid clay, evidently the deposit left by the water. The old specus, long after it had been out of use, seems to have been employed by the quarrymen as it was a tunnel in the tufa rock just high and wide enough for a man to walk in, by cutting. away one side they made it wide enough for a horse and cart to carry the stone, and they raised the vault as high as was convenient for the purpose of making an entrance into the quarry. The series of wells descending into the old specus from the gardens above remain at intervals, with notches for steps cut in the rock to enable a man to go up and down when required. The course of the specus is cut off by the road to the Porta Ostiensis, but probably that road was originally carried over it at the crossing;

to the Marrana is just a hundred yards along the line of the wall of Servius Tullius, across this part of the valley or great primitive foss. The ground on the side of the wall is all made earth and rubbish, and two aqueducts are carried on arcades against the wall, one on either side. These arcades have not been traced beyond the Marrana, the

ground there being higher. At the Piscina Publica, where another pit was dug 20 ft. deep, the wall is built against the tufa rock, and there is a third specus in a tunnel in the rock under the wall.

Or perhaps the road was a deep foss-way, and the specus passed over the arch of the gate at this point, where four roads meet.

it then passed through another large subterranean quarry nearly under S. Prisca, to the cave reservoir at its mouth'.

Before arriving at the two large reservoirs just outside of the garden of the Sessorium, now Sante Croce, the specus of the Appia must have passed by another smaller reservoir at the same low level, near the ruins of the apse of a hall, miscalled the temple of Venus and Cupid. This seems likely to have been the point at which the branch specus, coming from the north, entered Rome, and it was then carried on to the two large reservoirs outside this garden, supposed to have been the Gemelli".

Below the "Salina" or salt warehouses on the bank of the Tiber, and near the "Porta Trigemina," the water was "distributed." This was also close under the Clivus Publicii, or the slanting zig-zag road leading up from the wharf to the top of the hill.

So far the general course can be traced; but the exact point of entrance into Rome could not be fixed without excavations, which have not as yet been made. There are, however, some data given by Frontinus which should not be overlooked, as they bear incidentally upon the course of some other of the aqueducts.

In the spring of the year 1870, another excavation was made close to this point, and a way was found into another old subterranean stone-quarry long out of use. Through this cave, or quarry, the specus of five different aqueducts pass on their way to the Tiber. Some of these come down at a steep decline, and the water of the whole seems to have been carried into the lowest one, the Appia, at this point. This specus must have been carried over the deep foss-way upon or under the arch of the gate of the old wall of the city, where four roads meet.

It

is also visible again in another old subterranean stone-quarry on the other side of the road, nearly under S. Prisca, and from thence it must have gone to the old cave, used as a reservoir near the Marmorata, and the Porta Trigemina, immediately under the monastery of S. Maria del Trinita di Malta, where the specus is again visible, and where the wells of other aqueducts run into the same cave reservoir at the mouth of the aqueducts in this part of Rome. One of these runs down a vertical pipe from the reservoir nearly over this cave, but under S. Sabina on the hill above, excavated in 1865, and described by M. Descemet (Sect. xi.) There is an

other large reservoir in the interior of the hill, still full of water, supplied by a spring rising there; the water from this still passes through the same passage to the Tiber. This is also said to have been called the cave of Faunus by the poets. It is probably also the same as that of Cacus, being a large natural cave, with a spring of water, and a natural reservoir of considerable size in it about knee-deep, the entrance to which is by a narrow passage made into the specus of the aqueduct. Such a cave might very well have been used to drive cattle into for concealment, and a resolute, well-armed man standing at the entrance might defend it against any number. Solinus (i. 7) says that the cave of Cacus was at the Porta Trigemina, and that he dwelt in the Salina, which are close by this spot. "Qui Cacus habitavit locum cui Salinæ nomen est, ubi Trigemina porta."

u On the wall of the smaller reservoir, the fragment of an inscription, relating to the Thermæ of S. Helena, now in the Vatican Museum, is said to have been found :--

D. N. HELENA. VEN. . . . AVG. MAT.
AVIA. BEATIS.

First, it should be remarked, that the water of the Appia was augmented by an additional stream. This was not accomplished till the time of Augustus. The source of this latter was on the same side of the Via Prænestina, but a little nearer to Rome (near the sixth milestone) we are told, and its course was, like the main stream, entirely underground. It was more direct, as its length was less than six miles and a-half, while the original stream, by its windings, required about eleven miles to complete the same distance".

It joined, however, the Appia at the " Spes (Specus) Vetus," and at the Gemelli', which was under (infra) the "Old Specus," it could be measured. This is an important landmark; it is well at once to observe that the usual interpretation of the passage as referring to a "Temple of Spes," and the statement that a temple occupied the site of some ruins which are marked thus in a few maps, (in most, Templum Veneris et Cupidinis) does not seem to fit the circumstances. It is proposed to read in both these two instances "Specus Vetus." The expression occurs, altogether, five times in Frontinus, and it will be most satisfactory therefore to consider the passages together, which will be done more conveniently in connection with the next aqueduct described.

The Torquatian and Plautian, or Pallantian gardens, seem by the

Frontinus says, c. 5, at the sixth milestone on the Via Prænestina, about nine hundred and eighty paces off to the left, and near the Via Collatina, this stream has its source. The sources both of the Aqua Appia and of the Augusta were traced by Signor Fabio Gori and Mr. J. H. Parker, in March, 1868, and were afterwards shewn to the British Archæological Society of Rome.

The source of the Appia was 780 paces off the road, between the 7th and 8th milestone. That of the Augustan 880 paces off, and by the 6th milestone. The former was measured to its termination, giving 114 miles. The latter went only to the "Specus Vetus" (which is two miles less) and gave 64 miles. Two miles is the distance from the Porta Maggiore to the Porta Trigemina and the Salaria. In all probability the Augustan branch was carried for the six miles into Rome along the bank of the Via Prænestina, here a deep foss-way between two high banks; and at a later period the Aqua Virgo was carried over it at a higher level, till within about half a mile of Rome, where it arrives at the outer bank of the great foss, and is

carried at a sharp angle to the north to the Pincian. The Appia, being much deeper, was carried straight on at the bottom of the great foss into Rome, and entered at the extreme eastern corner, under the line afterwards taken by the Claudian arcade, to the two great reservoirs or gemelli before mentioned; the main line running here parallel to it, a little to the south, till it reached the Piscina of S. Helena, the two lines converging at the gemelli.

There are considerable remains of two large reservoirs in a garden just outside of the boundary-wall of the Sessorium, which wall is of the time of S. Helena, on its western side. Some excavations made in them in 1869 under my direction shewed that they went to a great depth, the workmen being stopped by water. These two great reservoirs, so close together in the line of the Aqua Appia, seem to have been the Gemelli mentioned by Frontinus. From this point the specus can be traced along the Coelian, and the reservoirs are below the level of that specus (infra specum veterem).—F. ii. 65.