Although in an unfinished state, and merely palisaded, it was under the fire of the castle and the Napoleon battery. The guns, already mounted, comprised nine heavy cannon, eleven fieldpieces, and six mortars and howitzers; and, as the reserve artillery and stores of the army of Portugal were deposited in the castle of Burgos, General Dubreton had the power of increasing his armament to any extent he thought fit.
Two days passed before the allies could cross the river. On the 19th August the passage was effected, and the French outposts on St. Michael were driven in. That night, the hornwork itself was carried after a sanguinary assault, the British losing in this short and murderous affair upwards of four hundred men.
From the hill, now in possession of the allies, it was decided that the future operations should be carried on, and the engineers arranged that each line in succession should be taken by assault. The place, on a close examination, was ascertained to be in no respect formidable; but the means to effect its reduction, by comparison, were feebler still. Nothing, indeed, could be less efficient; three long 18-pounders, and five 24-pound howitzers, formed the entire siege artillery that Lord Wellington could obtain.
The headquarters were fixed at Villa Toro. The engineering department intrusted to Colonel Burgoyne, and the charge of the artillery to Colonels Robe and Dickson.
The second assault, that upon the exterior wall, was made on the night of the 22nd by escalade. Major Laurie of the 79th, with detachments from the different regiments before the place, formed the storming party. The Portuguese, who led the attack, were quickly repulsed, and though the British entered the ditch, they never could mount a ladder. Those who attempted it were bayoneted from above, while shells, combustibles, and cold shot were hurled on the assailants, who, after a most determined effort for a quarter of an hour, were driven from the ditch, leaving their leader, and half the number who composed the storming party, killed and wounded.
After this disastrous failure, an unsuccessful attempt to breach the wall was tried, in effecting which, of the few guns in battery, two were totally disabled by the commanding fire of the castle, and the engineers resorted, from sheer necessity, to sap and mine. The former, from the plunging fire kept up from the enemy’s defences, and which occasioned a fearful loss, was speedily abandoned; but the latter was carried vigorously on, and the outward wall mined, charged, and, on the 29th, exploded.
At twelve o’clock at night the hose was fired, the storming party having previously formed in a hollow way some fifty paces from the gallery. When the mine was sprung, a portion of the wall came down, and a sergeant and four privates, who formed the forlorn hope, rushed through the smoke, mounted the ruins, and bravely crowned the breach. But in the darkness, which was intense, the storming party and their supporting companies missed their way, and the French recovering from their surprise, rushed to the breach, and drove the few brave men who held it back to the trenches. The attack consequently failed, and from a scarcity of shot no fire could be turned on the ruins. Dubreton availed himself of this accidental advantage, and by daylight the breach was rendered impracticable again.
Still determined to gain the place, Lord Wellington continued operations, although twelve days had elapsed since he had sat down before it. A singular despondency, particularly among the Portuguese, had arisen from those two failures; while insubordination was creeping into the British regiments, which produced a relaxed discipline that could not be overlooked, and which, in general orders, was consequently strongly censured.
The siege continued; and, on the 4th of October, a battery opened from Saint Michael’s against the old breach, while the engineers announced that a powerful mine was prepared for springing. At five o’clock that evening the fusee was fired. The effect was grand and destructive; one hundred feet of the wall was entirely demolished, and a number of the French, who happened to be near it, were annihilated by the explosion. The 24th regiment, already in readiness to storm, instantly rushed forward, and both breaches were carried, but, unfortunately, with heavy loss.
A lodgment was immediately effected, and preparations made for breaching the second line of defence where it joined the first.