After collecting a number of little tributary springs, at the distance of seven miles from the city, they flowed on towards Rome, each in its own channel, but over the same arches. The Julia was the highest, the Marcia the lowest of the three. About thirteen years afterwards, the same Agrippa brought to Rome the Aqua Virginis, so called from the circumstance, as related by Frontinus, that when some * "Why do these aqueducts cross the Campagna in courses so unnecessarily long and indirect! Several reasons have been alleged, all of which may have influenced the ancients but their chief ; motive, in my opinion, was, to distribute part of the water to the Campagna itseli, and to diffuse it there in smaller veins. Besides this general circuit, the Romans bent their aqueducts into frequent angles, like a screen, not so much to break the force of their currents, as to give stability to the arcades." [Forsyth, p. 133.] t Burgess, vol. ii., p. 328.

16 PRELIMINARY ESSAY. of Agrippa's soldiers were seeking for water, a young girl pointed out to them certain rills,

which, having followed up, they came to a copidus supply of water. In a little temple built on the spot, a picture is suspended, commemorating the event. The springs thus found were surrounded with a brick wall, and in their course augmented by several small streams, and the united waters were carried to Rome by an aqueduct of about fourteen miles, of which about three-fourths of a mile are above ground, and one half of the distance on arches.