Claudia, the Julia, the Tepula, and the Marcia ; the waters of all these five aqueducts could, however, be conducted to every part of the city. The Anio Vetus was in the sixth rank, as to level, though from the height of its source, it might have been conveyed to the loftiest parts of the city. The Aqua Virgo, and Aqua Appia, of which the sources were " The desert which * T7ie unpeopled Campagna. encircles Rome owed its ancient salubrity, not to any natural advantages which it now wants, but to the population and tillage of the Latin States. During the Empire the public ways were lined with houses from the city to Aricia, to Tibur, to the sea. In the interval between these lines, the town and country were so interwoven, that Nero projected a third circuit of wall, which should embrace half the Campagna. At that period the bad air infected but a small part between Antium and Lanuvium nor did it desolate these, for Antium grew magnificent under different emperors, and Lanuvium ;

was surrounded with the villas of the great. At length when a dreadful succession of Lombards, Franks, and Saracens destroyed the houses, pavements, drains, crops, plantations, and cattle which had protected the Campagna from mephitism, it then returned to its own vicious propensity, for both the form of its surface and the order of its soil promote the stagnation of water." [Forsyth, p. &H ]

18 PRELIMINARY ESSAY.

in the Campagna, were necessarily on a low level, and the Alsietina, on the lowest of all,