146

HISTORY OF ENGINEERING.

Bock I.

island, on which was erected the pharos. At the extremity of each of the moles was atower, in which was placed the machinery for extending a chain across the opening.

Fig.158.

NERO’S PORT AT ANTI I’M.

TarenUim consists of two ports, the outer called Mare Grande, the inner Mare Piccoli.A bridge of seven arches unites the present city to the continent on the north side, through

Fig.159.

TARENTUM.

which the sea flows with great impetuosity; this formerly was the entrance into the harbour,which will now only admit small boats. In the time of the Romans there were drawbridges,to enable the military in the citadel to command the inner port. The enemy s fleet in thesecond Punic war was so completely blocked up within it, that it could not regain thesea. *

Between the arches of the bridge was a wooden frame, to which nets were attached for