220 AQUEDUCT conveyed over it in two separate channels, are the AQITA CLAUDIA and the ANIO Novus, and from the three inscrip tions above the arches it appears (1.) that the Emperor Claudius had constructed the so-called Aqua Claudia Aque duct from the springs Cseruleus and Curtius, 45 miles from Rome; (2.) that the same emperor had constructed the so-called Anio Novus Aqueduct from the 62d milestone from Rome; (3.) that the Emperors Vespasian and Titus had restored these splendid undertakings of Claudius. Both aqueducts had been begun by Caligula, 38 A.D., and were completed ten years after by Claudius. The two springs from which the Aqua Claudia took its rise were in the Sabine hills near the 35th milestone, on the Via Sub- lacensis. It was augmented by part of the Aqua Martia, famous for the goodness of its water, and, owing to bends in the course, reached the length of 45 miles, as stated in the inscription, 35 miles of it being under and 10 above ground. The Anio Novus, so called to distinguish it from an older aqueduct, the Anio Vetus, took its rise in the river Anio at the 62d milestone, on the road just named, the water being first collected in a large basin, where it was allowed to purify itself. At the 32d milestone it was augmented by the clearer water of the spring, rivus Hercu- laneus. The entire length of 62 miles was partly above and partly below ground. About 6 miles from Rome it approached the Aqua Claudia, and from that point the two waters travelled together to the city in two distinct channels, one above the other, and supported by a chain of arches, which at one place reached the height of 109 feet. But in height these arches must yield to those of the aqueduct at Nismes, the ancient Nemausus, erected in the time of Augustus, which rose to 180 feet. The Pont du Gard, as the aqueduct at Nismes is now called, consists, as will be seen from Plate IV., of three rows of arches striding across the valley of the river Garden. In the lowermost row are six arches, of which one has a span of 75 feet, the others each 60 feet. In the second row are twelve arches, each with a span of 75 feet. In the third row are thirty-six smaller arches, immediately above which was the water-course. As a bridge, the Pont du Gard has no rival for lightness and boldness of design among the existing remains of works of this class carried out in Roman times. Besides the two principal aqueducts at Rome already described, there remain to be noticed twelve more which assisted in the supply of water for the city. These are (1.) AQUA APPIA, which took its rise at the foot of the Alban mountains on the Pneneste road, between the 7th and 8th milestones, and measured from its source to the Porta Trigemina 11,180 paces, of which 11,130 were below ground. It appears to have been the first important enter prise of the kind at Rome, and was the work of the old Censor Appius Claudius, from whom it derived its name. The date of its construction was the year of Rome 442, according to Frontinus, an overseer of aqueducts (curator aquarum) under the empire, whose work De Aquceduct. urb. Romce we still possess. (2.) ANIO VETUS, constructed forty years after the last-mentioned aqueduct, by the Censor Manlius Curius Dentatus, with the help of L. Papirius Censor, who finished it. From its source near Tivoli, on the left side of the Anio, it flowed 43,000 paces, of which 42,779 were below ground, and 221 above. At the dis tance of 2 miles from Rome (Frontinus, i. 21) it parted into two courses, one of which led to the horti asiniani, and was thence distributed; while the other (rectus duchis) led by the temple of Spes to the Esquiline gate, the site of which was near the modern Villa Negroni, where, in 1861, was found a subterranean conduit and an inscribed stone, which left no doubt as to its having been one of the atones set up to mark the distances of the Anio Vetus. (3.) AQUA MARTIA, rising on the left side of the Via Valeria, traversed 61,710 paces, of which 54,247 were underground, and the remaining distance carried partly on solid wall and partly on arches. It was the work of Quintus Martius Rex, not of Ancus Martius the fourth king of Rome, as Pliny (N.H., xxxi. 3) fancied, and took its name from its constructor. Its waters were celebrated for their coolness and excellent quality. (4.) AQUA TEPULA, from its source in the district of Tusculum, flowed 10,000 paces, mostly above ground, and on the^ same series of arches as carried the Aqua Martia, but at a higher level. It was the work of the Censors Cn. Servilius Csepio and L. Crassus Longinus, and was completed in the year 126 B.C. Again, partly on the same structure of arches, and with a still higher channel, flowed (5.) AQUA JULIA, from a source near that of the last-mentioned aqueduct to within 7000 paces of the walls of Rome, where the joint waters were received in a reservoir, and thence distributed in various channels to the city. Its entire length was 15,426 paces. It was constructed in the year 34 B.C. by Marcus Agrippa, to whose zeal to meet public wants in this direction were due the two other aqueducts (6.) AQUA VIRGO, and (7.) AQUA CRABRA or DAMNATA, the former as well known for the goodness of its water as was the latter for the inferiority which procured it the designation of Damnata. The Aqua Virgo, from its origin at a copious spring in a marsh on the Collatine way, not far from the ancient Gabii, measured 14,105 paces, along which it was conveyed in pipes, partly under and partly above ground, on a solid substructure or on arches. It was completed in the year 48 B.C. (8.) AQUA ALSIE- TINA or AUGUSTA rose in Etruria, on the Via Claudia, and travelled 22,172 paces, of which 358 were on arches. It was the work of Augustus, whose object was to furnish by it water for gardens and other than drinking purposes. (9.) AQUATRAJANA, rising in Lake Sabatinus (Bracciano), was constructed by Trajan. (10.) AQUA ALEXANDRINA, rising in the district of Tusculum, was the work of Alex ander Severus. (11.) AQUA SEPTIMIANA seems to have been only a branch led from the Aqua Julia to supply the baths of the emperor from whom it takes its name, Septi- mius Severus. (12.) AQUA ALGENTINA rose on Mount Algidus ; at whose instance it was made is unknown. Of the fourteen aqueducts which supplied ancient Rome, three remain in use at the present time, furnishing the modern city with abundance of water. The first of the three is the Aqua Virgo, now known as Fontana di Trevi, supplying the best water in Rome. It was restored by Pope Pius IV. The next is the Aqua Claudia, known as the Aqua Felice or di Termini, which was restored by Sixtus V. The third is the Aqua Trajana, called, from the Pope who restored it, viz., Paul V., Aqua Paole. At regular intervals along the course of an aqueduct were built reservoirs (casteUa), to enable repairs to be made at any point, and also to let off water for the popula tion of the district through which it passed. It was the law that material necessary for repairs should be supplied from the private property nearest to where the damage was, and should be conveyed at the cost of the owner of such property. Castella of smaller dimension were also required in many parts of the city. Of these, it was said, there were 247 in Rome. To allow the water to purify itself before being distributed in the city, large basins (piscinae limarice), were built outside the walls. For the process of purification salt was used (Vitruvius, viii.) These piscina? were covered in with a vaulted roof, and were usually on a colossal scale, as in the example still pre served at Fermo, which consists of two stories, each having three oblong basins communicating with each other; or the
Piscina Mirabile at Bai;e, which is covered in by a vaulted