Chap. IV.

ROMAN.

133

of work was accomplished by merely throwing into the ocean the earth obtained fromPuteoli , which, when immersed in the sea, became as solid and compact as a hard rock :this earth was a compound of alumina, bitumen, and sulphur, not differing muchfrom that found at Cyzicena, which, when cut into large blocks and sunk under water,had the property of hardening. The younger Pliny , lib. vi. let. 32., writing from theneighbourhood of Ostia , describes the progress made at the port of Centocella?, thusenabling us to judge of the method by which the Homans conducted such operations.“ The left hand of the port is defended by exceeding strong works, and they are nowemployed in carrying on the same on the opposite side. An artificial island, which isrising at the mouth of the haven, will break the force of the waves, and afford a safe

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channel to ships on each side. In the construction of this wonderful instance of art, stonesof a most enormous size are transported either in a large sort of pontoon or raft, and, beingpiled one upon another, are fixed by their own weight, and gradually accumulate in themanner of a natural mound. It already lifts its rocky back above the ocean, while thewaves which beat upon it, being tossed to an immense height, foam with a prodigious noise,and whiten all the sea around. To these stones are added large blocks, which, when thewhole shall be completed, will give it the appearance of an island just emerged from thesea." The above was written from his villa at Centocell®.

Ostia was formed into a port in the year of Rome 132, by Ancus Martius , who also con-structed the first wooden bridge over the Tiber ; and here, in after times, were threeseparate ports, affording secure retreat to vessels on that dangerous coast, constructed byAugustus, Claudius, and Trajan : the latter, that alluded to by Pliny , was destroyed by thechanges which took place in the bed of the Tiber. The ancient port of Ostia was abouthalf a league from the sea, and five leagues south-west of Rome , near the mouth of theTiber. At Porto, now a small village, and a league from Ostia , on the other side ofthe Tiber, are considerable remains of the town which the emperors Claudius andTrajan caused to be built. The basin of the ancient port of Trajan may be seen,with fragments of many of the buildings represented on his coins.

The port constructed by Claudius, in advance of that of Trajan , was amongst theboldest executed by Roman engineers: — an oval sheet of water, enclosed from theocean by broad and spacious moles, affording a safe haven for vessels which navigatedthe western shores of Italy : an artificial island lay between the horns of these twomoles, with towers at each extremity, containing machinery and tackle of variouskinds, by which the boatmen could at all times enter safely. These constructions musthave been a work of prodigious labour; their solidity is attested by the writers ofthe time, particularly by Pliny . In the middle of this island stood a pharos, before w’hichwas the colossal statue of the emperor Claudius . Fire was placed, at the approach ofnight, in the upper story of this lofty structure, which could be seen from a considerabledistance. Orders of the purest architecture decorated three of the stories, and ingeniously

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