There were many fountains along the streets of Pompeii, most of them at the corners. They were fed by pipes connecting with the water system of the city. The construction is simple. A deep basin was made by placing on their edges four large slabs of basalt, held together at the corners by iron clamps. Above one of the longer sides, usually near the middle, is a short, thick standard, of the same stone, pierced for the lead feed pipe, which threw a jet of water forward into the basin below; on the opposite side is a depression through which the superfluous water ran off into the street. Most of these standards are ornamented with reliefs, roughly carved but effective,--an eagle with a hare in its beak, a calf's head, a bust of Mercury, a head of Medusa, a drunken Silenus (Fig. 103), or some other suitable design, arranged so that the water would spurt from the mouth of the figure or from an amphora. Occasionally we find a fountain of finer material. That of Concordia Augusta, of limestone, has already been mentioned (p. 117). In the neighborhood of the Porta Marina there is a fountain of white marble with a relief showing a cock that has tipped over a jar, from the mouth of which the water flowed. Both these more costly fountains were probably the gift of private individuals, one presented to the city by Eumachia, the other by the owner of the nearest house, at VII. xv. 1-2. All the fountains bear witness to long use by the depressions worn in the stone by the hands of those leaning forward to drink. Water towers stand at the sides of the streets, small pillars of masonry preserved ordinarily to the height of 20 feet. Usually on one side there is a deep perpendicular groove (shown in Fig. 103) in which ran the pipe that carried the water to the top of the tower, where it was received by a small open reservoir, presumably of metal, and distributed through numerous small pipes leading to the fountains and to private houses. The sides of the towers are often covered with incrustations of lime deposited from the water, in which the impressions of the lead pipes are still to be seen; in the case of one tower, at the northeast corner of Insula VI. xiii, a number of the pipes have been preserved. A reservoir was placed also on the top of the commemorative arch at the lower end of Mercury Street, on which stood the bronze statue of Nero or Caligula (p. 48); the traces of the pipes leading from it are clearly seen on the surface of the arch. Similar water towers are in use now in Constantinople and Palermo, having been introduced into the latter city, it would seem, by the Saracens, who very likely took their water system from that of the Turkish capital. [Illustration: Fig. 103.--Fountain, water tower, and street shrine, corner of Stabian and Nola streets.]