Knight's Gate (ai 'Iññadеs л.), probably between the hill of the Nymphs and the Pnyx. 5. The Melitian Gate (ai Medɩrides π.), so called because it led to the demus Melite. It was between the Pnyx and the Museum hill. On the south side: 7. The Itonian Gate (ai 'Irovia π.), near the Ilissus, where the road to Phalerum began. 8. The Diomean Gate ( Atóμeta π.), leading to Cynosarges and the demus Diomea. On the east side: 9. The Gate of Diochares (ai Aioxáроνs π.), leading to the Lyceum. On the north side: 10. The Acharnian Gate (ai 'Aɣaρviкaì π.), leading to the demus Acharnæ.

AQUEDUCTS.-The supply of water in the Grecian towns in early times was chiefly from springs and cisterns hewn in the rock. The insufficiency of water from these sources led to the necessity of receiving larger supplies through tunnels and conduits from hills near the towns. In Athens, under the rule of Pisistratus (B.c. 560) an extensive series of works was completed to bring water from the hills Hymettus, Pentelicus, and Parnes. From Hymettus were two conduits passing under the bed of the Ilissus, and the most part of the course was cut in the rock. Pentilicus, richer in water, supplied another conduit. Outside Athens those two conduits met in a large reservoir, from which the water was distributed by a ramification of underground channels throughout the city. Aqueducts were scarcely known in Greece before the time of the Romans. In Italy, in early times, constructions for the conveyance of water, consisted of an oblong basin, divided into several chambers, which received the water of a spring, and then distributed it by pipes (tubi, fistulæ) or canals. Of these there is an example at Tusculum. The basin is built of blocks of stone, which, along the sides, overlap each other, till they meet and form a roof.

At a later period aqueducts were used by the Romans. Remains of those stupendous structures are to be met with not only in the neighbourhood of Rome, but also throughout the Roman provinces in Europe, Asia, and Africa. They were apparent or subterranean. The latter, which sometimes traversed considerable space, and were carried through rocks, contained pipes (fistulæ, tubuli) of lead or terra cotta, frequently marked either with the name of the potter, or the name of the consuls in whose time it was laid down. At convenient points, in the course of these aqueducts, as it was necessary from the water

being conveyed through pipes, there were reservoirs (piscina), in which the water might deposit any sediment that it contained. Vitruvius has given rules for the laying down of pipes, and for forming reservoirs. The apparent aqueducts were built on the most stupendous scale. Hills were pierced through by tunnels, and valleys crossed either by solid substructions or arches of masonry, according to the height required, bringing water from sources varying from thirty to sixty miles in distance. At one

period of the history of Rome no less than twenty aqueducts stretched their long line of arches, and brought as many different streams of water, across the wide plain or Campagna in which the city stands. For the most part they were built of brick, and consisted of nearly square piers running up to the same height-a slight and uniform declivity being necessarily maintained—and connected by semicircular arches, over which the conduit (specus, canalis) ran. This conduit had a paved or tiled floor, and was enclosed laterally by walls of brick or stone lined with cement, and with a transverse arch, or by a simple flat coping of stone. The water either ran directly through this conduit, or was

carried through pipes laid along its floor. These aqueducts were either simple, double or triple, according as they were composed of a single, two, or three tiers of arches. At the termination of the aqueduct, within the city, was a vast reservoir called castellum, which formed the head of the water, from which it was conducted through pipes into smaller reservoirs, and thence was distributed through the city, thus supplying the public fountains, baths, and houses. The chief castellum was, externally, a highly decorated building. The so-called trophies of Marius, at Rome, are supposed by Piranesi to have been ornaments of a castellum or reservoir of the Aqua Julia. Excavations made some years ago seem to confirm his opinion. Remains of works of art found near the castellum prove that it must have had a very ornamental exterior.

We shall begin our enumeration of the principal aqueducts by the most ancient in Rome. Before the year of Rome, 441, the city was supplied with water from the Tiber only. In that year (B.c. 313) Appius Claudius, the censor, constructed an aqueduct which brought water from a distance of seven miles; it was called Aqua Appia, after him. It began to the left of the Via Prænestina; and, according to Frontinus, its whole course, except sixty paces near the Porta Capena, was under ground. This last portion was on arches. No traces of it remain.

The Anio Vetus was constructed by M. Curius Dentatus, B.C. 272, and was finished by M. Fulvius Flaccus. The water was derived from a source of the river Anio, near Augusta, twenty miles beyond Tibur, and about forty-three from Rome. It was built of peperino stone. A small portion of this aqueduct is still visible outside the Porta Maggiore.

The Aqua Marcia was constructed by the prætor, Q. Marcius Rex, by command of the senate, B.C. 144. It had its source in a small stream which runs into the Anio, not far from the present town of Subiaco, about thirty-seven miles from Rome. It was repaired by Agrippa. The latter portion of this aqueduct for about six miles from Rome was on arches, the remains of which form one of the most interesting features of the Roman Campagna. It is remarkable for the excellence and wholesomeness of its water.

The Aqua Tepula was constructed by Cneus Servilius Cæpio

and L. Cassius Longinus, B.C. 127. It had its source near the tenth milestone on the Via Latina.

The Aqua Julia was executed by Agrippa in his ædileship, B.C. 33, and was so called in honour of Julius Cæsar. This aqueduct was a union of three streams: the Aqua Marcia, the Aqua Tepula, and the Aqua Julia, properly so called, which had its source two miles beyond that of the Aqua Tepula. It supplied the Esquiline and Palatine hills. It was built partly on massive substructions and partly on arches. The so-called Sette Sale are supposed to have been a reservoir of the aqueduct for the use of the baths of Titus.

The Aqua Virgo was constructed by Agrippa, under Augustus, to supply his baths. Its source was between the seventh and eighth milestone, on the Via Collatina. It derives its name from the tradition that its source was pointed out by a young girl to some thirsty soldiers. It entered Rome near the Porta Pinciana, from whence it was conducted on arches to the Campus Martius. The greater portion of it was subterranean, a small portion of about 700 paces, was on arches. This aqueduct still supplies a large part of modern Rome.

The Aqua Alsietina, on the right bank of the Tiber, was brought by Augustus, from the lacus Alsietinus, to supply his naumachia. It was about thirty miles long.

The Aqua Claudia was commenced by Caligula, A.D. 36, continued and finished by the emperor Claudius, A.D. 50. The springs from which it derived its water were near the thirtyeighth milestone, on the Via Sublacensis, a few miles from Sublaquem (Subiaco). It was more than forty-six miles long. At the present day a line of arches belonging to this aqueduct extend for about six miles across the Campagna, forming the grandest and the most picturesque vista on the plain near Rome. The arches were afterwards used by Sixtus V. to supply the city from another source, under the name of the Aqua Felice.

The Anio Novus, also built by Claudius, was the longest of all the aqueducts, being nearly fifty-nine miles long. Its source was near the forty-second milestone, on the Via Sublacensis. This aqueduct, with the Aqua Claudia, entered the city over the

present Porta Maggiore, in two channels, one above the other. The upper was the Anio Novus, the lower the Aqua Claudia.

It has been calculated that these nine aqueducts furnished Rome with a supply of water equal to that carried down by a river thirty feet broad by six deep, flowing at the rate of thirty inches a second. There were four other aqueducts of later construction which may be added to the list.

The Aqua Trajana was brought by Trajan from the Lacus Sabatinus (Bracciano) to supply the Janiculus and the Regio Transtiberina. The Aqua Alexandrina was constructed by Alexander Severus; its source was in the lands of Tusculum, about fourteen miles from Rome, between Gabii and the lake Regillus. The Aqua Septimiana seems to have been only a branch of the Aqua Julia, formed to supply the baths of the emperor from whom it takes its name, Septimius Severus. The Aqua Algentia had its source at M. Algidus. Its builder is unknown.

There was also the Aqua Crabra, which had its source near that of the Julia, but the water was so bad, that it was abandoned, and hence was called Aqua Damnata.

These seem to have been the fourteen aqueducts, which were still in use at Rome in the time of Procopius. These magnificent and useful works of the ancient Romans were not confined to the capital alone. Constructions of equal magnificence and utility, some even on a grander scale, are to be found not only in the provinces near Rome, but even in the remotest parts of the empire. Among those constructions to be met with in the provinces, the most remarkable for the scale of its magnificence and grandeur, far exceeding anything of the kind in Italy, is the so-called Pont du Gard, which supplies Nismes with water. It consists of three tiers of arches one above the other: the first tier contains six arches; the second, eleven; the third, thirtyfive. The whole height is 182 feet; the channel in which the water runs is three feet high. The aqueduct of Segovia, in Spain, is also a Roman work, exhibiting great perfection and solidity in its construction. It is built entirely of stone, in two ranks of arches, the piers being eight feet wide and eleven in depth; 150 arches still remain. The effect, however, is much marred by the houses and other objects that crowd their bases. In the opinion of Mr. Fergusson the aqueduct at Tarragona bears a character of lightness combined with constructive solidity and elegance unrivalled in any other work of its