138

HISTORY OF ENGINEERING.

Book I.

placed the pharos, and by a projection of the shore into the sea, forming a small cape, com-prised between the Pisco Montano and the Torre Gregoriano ; from the latter point to theextremity of the port, the slope of the shore is from north-west to south-east. Theexternal part of the wall of this enclosure has a considerable talus; the ancient rocks stillremain at its base. The facing on the internal part is perpendicular, and holes in marbleblocks remain, through which the cables were passed when the vessels were moored.

The mole, which forms the enclosure, was raised 12 feet in height above low water ; itswidth at the top is 40 feet, and there are few works more substantial or solid to be met with.

Some remains of columns and their entablature lie at the foot of the mole, and in allprobability they once adorned a structure on the platform which was the residence of theofficers of the port. The foundation or establishment of these works are of great antiquity,and are said to be the first regular constructions of this kind in Italy . In many parts theopus reticulatum may be seen: we know that it was restored by Antoninus Pius .

Adria , whence the Adriatic derived its name, was the ancient Atria; it is 32,000 metresfrom the sea; Rimini is 1500, and Ravenna 8000. At Rimini terminated the two greatroads, the Emilian and the Flaminian; here was a triumphal arch and a bridge, which wereerected in the time of Augustus . A canal conducts small craft from this once famous portto the sea.

A variety of methods was employed in the construction of double dams, formed of pilesand planks, chained or tied together, and filled in with clay and marsh weeds, well rammedin or puddled, to keep out the water. When this was effected, the water was pumped outby the various machines then in use, and which were most effective for the purpose. 'HieArchimedean screw and water wheels were employed, after which the foundations weredragged or dug out; when, if soft, alder, olive, or oak piles, previously charred, weredriven in, and the intervals between their heads filled with charcoal or some other equallyimperishable material. On this, walls of squared stone, in regular courses, were laid,taking care that the longest were employed as bond-stones, to pass into the thickness of thewall, and thus tie in the others. The inside of the wall was then filled with rubble ormasonry, and on such work, towers were built. The arsenals around a port usually hada northern aspect, the heat being supposed to encourage the teredinos and other destructiveworms, and they were generally constructed of a material not likely to take fire. Thesebuildings were for the purpose of receiving the largest ships, which were drawn on shore,and protected under them.

Naples is in 40° 50' north latitude, and 14° 14' east longitude; this city is of Grecianorigin. Livy mentions it as joining with the inhabitants of Pala?polis and the Samnites

Fig. 148.

NAPLES.

against the Roman power. It is situated in the bosom of a capacious bay, and the har-bour is formed by a mole, built in two directions, having its lighthouse at the bend.Within the mole, the ground is soft, being covered with three or four fathoms of water.This city, from the number of its inhabitants and its beauty, has been styled the Queen of the