To avoid useless loss of men, he withdrew the garrison from the bridgehead. The defences, consisting only of piles of loose stones and rubble, while effective against bullets, must soon be knocked to pieces by shells, even from field-guns, and would prove only a death-trap to men congregated behind them. He had reason to be thankful for the precautions he had taken when the enemy, after sending shell after shell into the vacant emplacement until it was thoroughly demolished, got to work on the bridgehead. Some twenty rounds reduced this, the first line of defence, to a mere rubbish heap. Fortunately the enemy did not suspect the existence of the main trench which had been dug in the rear, and was masked by the embankment on the shore of the island. Having destroyed the bridgehead, the Turkish gunners began to search the embankment methodically, dropping shells at every few yards along the front. The embankment, consisting of deep and closely packed mud, could not be broken down by the light shells from field-guns; but the bombardment would have played havoc with the defenders if, as the Turks no doubt supposed, they were extended behind it. As soon as their intentions became clear, Burnet withdrew the machine-gun from the second emplacement to the third, which was well retired from the shore and beyond the enemy's immediate objective. This precaution turned out to be unnecessary, or at least premature, for the bombardment was limited to about two hundred yards on each side of the bridgehead. Seeing that the second emplacement was outside the enemy's present zone of fire, Burnet had the machine-gun quickly restored to its former position. Hitherto the Arabs had not fired a single shot in answer to the bombardment. Not a man of the enemy was in sight, and the guns were far away on the mainland, completely hidden. The Arabs, at first alarmed by the deafening explosions and the devastating effects of the shells, had begun to recover tone when they saw that the damage was mainly material. A few of them had been hit by flying splinters of stone, but their injuries were light, and none had been killed. At last the bombardment of the embankment ceased. A few moments later shells began to fall on the ruined buildings in the centre of the island. Anticipating this, Burnet had told the small body of Arabs whom he was holding there in reserve what to do, and they, with Rejeb, had already taken refuge in the deep underground chambers.