until the time of Caligula, when the seven existing aqueducts being found insufficient for the increase of luxury and popu- lation, this emperor, in the 789th year of Rome, began two new ones. These were finish- ed by the Emperor Claudius with great magnificence, and opened for use in the year of Rome 803. The first was named Aqua Claudia, and the second Anio Novus, to dis- tinguish it from the other Anio, which was afterward called Vettis, or the Ancient. The source of the Aqua Claudia was from two fine springs called Cseruleus and Curtius, at a distance of thirty-eight miles from the city, on the Via Sublacensis, 300 paces within on a path to the left. The Aqua Claudia was next in quality to the Aqua Marcia. The whole length of this wonderful aqueduct was 46 miles and 406 paces, of which 36 miles and 210 paces were subterraneous ; the remaining 10 miles 176 paces were carried * Burgess, vol. ii., p. 332. PRELIMINARY ESSAY. 17 over arches in different places as the level required, viz : in the more distant parts 3 miles, 78 paces, and at seven miles from the city, those arches began rising in height as they stretched towards the capital, running in some places parallel with the Marcian Aqueduct, and sometimes coming in contact with it, as they both approached their termination. Near the Arco Furbo, about three miles on the road to Frascati, the two aqueducts cross one another, and the whole, as seen stretching over the now unpeopled Campagna,* forms one of the most striking objects that can be imagined. It was in the Claudian aqueduct that Sextus V. conveyed the Aqua Felice. Finally, to complete the account of Frontinus, the Anio Novus (also brought by Clau- dius) took its rise on the Via Sublacensis, at the 42d mile-stone. It was, as the name implies, a portion of the river Anio. This river, traversing a rich and highly cultivated region, was mixed in times of rain with a quantity of the soil. On this account a puri- fying piscina or reservoir was interposed between the river and the mouth of the aque- duct, in which the water settled before entering the channel-ways. In spite, however, of this precaution, the water in times of violent floods was frequently discolored, when it reached the city. Another streamlet, called Herculaneus, rising on the same road, about 38 miles from Rome, and of which the waters were remarkably limpid, was conducted into the Anio Novus, but in time of rain, its advantages were lost by the mixture with the more abundant Anio. This stupendous aqueduct extended the vast distance of 62 miles — 48 miles and 300 paces being subterraneous. The rest was carried over such lofty arches, that in some places they rose to the height of 109 feet. - All these aqueducts were carried to Rome on different levels, and their waters were dis- tributed to the several parts of the city, to which their respective elevations were the best adapted. The Anio Novus flowed on the highest line, and the others in this order : the 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 * T7ie unpeopled Campagna. — " The desert which encircles Rome owed its ancient salubrity, not to any nat- ural 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 Cam- pagna 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 ] 5 18 PRELIMINARY ESSAY. in the Campagna, were necessarily on a low level, and the Alsietina, on the lowest of all, was distributed in quarters about the Tiber, and