More attractive, though not more useful, monuments of labor and care for the public health, remain in the aqueducts, by which a plentiful supply of water was always insured to the city of the seven hills--the mere dilapidated remains of which still suffice for her present use. A mere glance at the proportions of some of these noble works, which conveyed the purifying and health-giving element, through hills and across valleys, from sources varying in distance from sixty miles downward, may well raise a blush at the scant and meagre substitutes which we can show in the nineteenth century. Well may Frontinus, in an exulting tone, compare the useful splendor of the nine aqueducts, which in his time supplied the city, with the useless, slave-grown bulk of the pyramids, or the merely decorative works of Grecian towns.
The most remarkable of the nine aqueducts were the Anio Vetus, the Aqua Marcia, the Aqua Claudia, and the Anio Novus. The Anio Vetus brought a supply from the river Anio, a distance of forty miles. It was built B. C. 273, and consisted of a stone water-course, the channel of which was coated with cement. A still longer one was the Aqua Marcia, extending along a distance of fifty-four miles, six and a half miles being above ground, and chiefly supported on arches. So lofty was the level of the terminal reservoir, that the highest parts of the Capitoline Mount could be supplied from it. This aqueduct united toward its termination with two others, in the same pile of masonry, so as to form one range of building, in which the three water-courses occupied different levels, one above the other, and finally discharged their streams into the same reservoir. At the same period that this aqueduct was constructed, 700 wells, 150 springs, and 130 subordinate reservoirs, were added to the former sources of supply. The Marcian Aqueduct was remarkable for the vastness and solidity of its proportions and construction.
Augustus caused an aqueduct to be built specially for the purpose of supplying the vast basin in which he exhibited sham naval fights to the citizens: but the Anio Novus, one of two new aqueducts built by the Emperor Claudius, was the most striking of all in its architectural effect. For six miles before its entrance into the city the water flowed along a channel supported by arches, some of which reached the height of 109 feet, and constituted a range of great beauty.