At the back of the whole of the rest of the breach was a perpendicular fall, from fifteen to twenty-five feet in depth, under which were the ruins of the houses which joined on to the back of the breach; and here and there was left an end wall of the houses, by which alone it was possible to descend. A line of retrenchment carried along the nearest standing parallel walls, was strongly occupied by the enemy, and which entirely swept the confined summit of the breach.
The storming parties advanced to the breach, and there remained on the side of it without being able to crown the top, from the heavy fire from the intrenched ruins within. Many desperate efforts were made to gain it, without effect, particularly up to the curtain; but the enemy maintained that post firmly. Fresh troops were sent on successively, as fast as they could be filed out of the trenches, with laudable perseverance; and the Portuguese, in two detachments, forded the river Urumea, near its mouth, in a very handsome style, under a heavy fire of grape and musketry.
The breach was now covered with troops remaining in the same unfavourable situation, and unable to gain the summit. Upwards of two hours of continued exertion had elapsed, when, by a happy chance, a quantity of combustibles exploded within the breach, and the French began to waver; the assailants made fresh efforts; the ravelin and left branch of the hornwork were abandoned by the enemy; the retrenchment within the breach was soon after deserted by them; and the men by degrees got over the ruins and gained the curtain.
The troops, being now assembled in great numbers on the breach, pushed into the town; the garrison, dispirited at its great loss, and intimidated at the perseverance shown in sending fresh men, was quickly driven from all its entrenchments, except the convent of St. Teresa, into the castle.
From the superior height of the curtain, the artillery in the batteries on the right of the Urumea were able to keep up a fire on that part during the assault, without injury to the troops at the foot of the breach, and being extremely well served, it occasioned a severe loss to the enemy, and probably caused the explosion which led to the final success of the assault.
The assailants had upwards of five hundred killed and fifteen hundred wounded; of the garrison, besides the actual killed and wounded during the assault, seven hundred were made prisoners in the town. Of the engineers, Lieutenant-colonel Sir R. Fletcher, Captains Rhodes and Collyer, were killed; and Lieutenant-colonel Burgoyne, and Lieutenants Barry and Marshall, were wounded.
As soon as the town was carried, a communication was made from the left of the parallel to the salient angle of the ditch of the ravelin, through the counterscarp, which was blown in, and so into the town by the great gate; and preparations were made to reduce the castle.
The plan for the attack was to erect batteries on the works of the town, and breach some of the main points of the castle defences, as the battery de la Reyna, the Mirador, and the keep, as well as the thin loop-holed walls connecting them.
On the 2nd of September, a new battery for seventeen guns was commenced, occupying the whole terreplein of the hornwork, and another for three guns on the left of the cask redoubt.
A discussion for surrender was entered into with General Rey, but he broke it off.