Scipio, meanwhile, after having confined the besieged to the city itself, sought totally to cut off their intercourse with the outer world.

He took up his head-quarters on the ridge by which the Carthaginian peninsula was connected with the mainland, and, notwithstanding the various attempts of the Carthaginians to disturb his operations, constructed a great camp across the whole breadth of the isthmus, which completely blockaded the city from the landward side.

Nevertheless ships with provisions still ran into the harbour, partly bold merchantmen allured by the great gain, partly vessels of Bithyas, who availed himself of every favourable wind to convey supplies to the city from Nepheris at the end of the lake of Tunes; whatever might now be the sufferings of the citizens, the garrison was still sufficiently provided for.

Scipio therefore constructed a stone mole, 96 feet broad, running from the tongue of land between the lake and gulf into the latter, so as thus to close the mouth of the harbour.

The city seemed lost, when the success of this undertaking, which was at first ridiculed by the Carthaginians as impracticable, became evident.