In spite of the steady and well-directed fire of the citadel, the besiegers made steady progress. Their third and fourth parallels were directed against the lunette Saint Laurent; a mine was run under one of its bastions, and sprung on the night of the 14th December, making a practicable breach in the walls. Three companies of the 65th French regiment assaulted immediately, passed the ditch without firing a shot, and carried the breach at the point of the bayonet. At the same time a battalion of grenadiers took advantage of the springing of the mine and consequent confusion; they scaled the walls of the lunette on the opposite side, and the garrison of less than three hundred men was compelled to retire to the citadel with the loss of sixty prisoners, after making a most gallant defence.
The capture of this position was of great advantage to the French, as it enabled them to bring their approaches close to the edge of the ditch on the summit of the counterscarp. General Chassé planned a sortie, which was led by Captain Morré. It resulted in the capture of five mortars, and the levelling of some twenty-five yards of the trenches, but the working force of French was speedily strengthened, and the Dutch were beaten back with the loss of their captain, who was killed. Other sorties were made, the Dutch displaying great bravery, but the retardation of the work of the besiegers was hardly sufficient to compensate for the loss of men. Night and day the bombardment continued, and so vigorously was it carried on that as many as fourteen bombs were seen in the air at once.
The immense casemates of the citadel were not strong enough to stand the French fire. The casemates were broken through by the weight of the falling bombs; some of the missiles penetrated to the hospitals, piercing the six feet of earth piled upon the roofing of heavy timber, and exploding in the midst of the sick and wounded.
