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- It was, as the name dius) took its rise on the Via Sublacensis, at the 42d mile-stone. 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 purifying piscina or reservoir was interposed between the river and the mouth of the aqueduct, 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.