ground, but retired to send for Hasdrubal and fortify with trenches and palisades the cross-wall in front of the residences.  Scipio now left Mancinus to guard Megalia and himself set out to join Piso and the troops so as to have their support in his conduct of operations.  He made a rapid return journey with the lightest equipped portion of the army and found that Hasdrubal had entered Carthage and was attacking Mancinus fiercely.  The arrival of Scipio put an end to the attack.  When Piso too had come there, Scipio bade him take up his position outside the wall opposite certain gates, and he sent other soldiers around to a little gate a long distance away from the main force, with orders as to what they must do.  He himself about midnight took the strongest portion of the army, got inside the circuit (using deserters as guides) and moving quietly to a point inside the little gate he hacked the bar in two, let in the men who were on the watch outside and destroyed the guards.  Then he hastened to the gate opposite which Piso had his station, routing the intervening guards (who were only a few in each place), so that Hasdrubal by the time he found out what had happened could see that nearly the entire body of Roman troops was inside.  For a while the Carthaginians withstood them:  then they abandoned the city, all but the Cotho and Byrsa, in which they took refuge.  Next Hasdrubal killed all the Roman captives in order that his people in despair of pardon might show the greater fortitude in resistance.  He also made away with many of the natives on the charge that they wanted to betray their own cause.  And Scipio encircled them with trench and palisade and intercepted them by a wall, yet it was some time before he took them captive.  The walls were strong and the men within being many in number and confined in a small space fought with vehemence.  They were well off for food, too, for Bithias from the mainland opposite the city sent merchantmen, amid wind and wave into the harbor to them so often as there was a heavy gale blowing.  To overcome this obstacle Scipio conceived and executed a startling operation, namely, the damming of the narrow entrance to the harbor.  The work was difficult and toilsome, for the Carthaginians undertook to check them, yet he accomplished it by the number of laborers at his disposal.  Many battles took place in the meantime, but the enemy were unable to prevent the filling of the channel.

IX, 30.—­So when the mouth of the harbor had been filled up, the Carthaginians were terribly oppressed by the scarcity of food; some of them deserted, others endured it and died, and still others ate the dead bodies.  Hasdrubal, accordingly, in dejection sent envoys to Scipio with regard to truce, and would have obtained immunity, had he not desired to secure both preservation and freedom for all the rest as well.  After he had failed for this reason to accomplish his purpose he confined his wife in the acropolis because she had made propositions to Scipio for the