When the first mine should be completed, the battery from San Michael was to open against the second line of defence, and the assault given on the first line. Approaches were then to be continued against the second line, and the battery turned against the third line, in front of the White Church, where the defences were exceedingly weak. Meanwhile a trench for musketry was to be dug along the brow of San Michael, and a concealed battery prepared within the horn-work for a final attack on the Napoleon battery; but the artillery consisted of only three eighteen-pounders with five iron twenty-four-pound howitzers: slender means which, rather than the defects of the fortress, governed the line of attack.
When the horn-work fell, a lodgement was commenced in the interior, and continued vigorously under a destructive fire from the Napoleon battery, but good cover was obtained in the night.
On the 21st the garrison mounted several field-guns, and at night fired heavily with grape and shells on the workmen digging the musketry trench. The 22nd this fire was redoubled, yet the besiegers worked with little loss, and their musketeers galled the enemy. In the night the battery was armed with two eighteen-pounders and three howitzers, and the secret battery within the horn-work was commenced; but Wellington, now deviating from his first plan, directed an escalade against the first line. In this view, at midnight four hundred men with ladders were secretly posted in a hollow road, fifty yards from the wall, which was from twenty-three to twenty-five feet high without flanks; and to aid this main column, a Portuguese battalion was assembled in the town of Burgos for a flank attack.
Second Assault. (Sept. 1812.)
In this assault, although the Portuguese were repelled by the fire of the common guard, the principal party, composed of detachments under Major Lawrie, entered the ditch, yet altogether and confusedly; Lawrie was killed, the soldiers who mounted the ladders were bayoneted, combustible missiles were thrown down in abundance, and the men gave way, leaving half their number behind. The wounded were brought off next day under a truce, and it is said, that on the body of an officer the French found a complete plan of the siege. It was a very disastrous attempt, which delayed the regular progress for two days, increased the enemy’s courage and produced a bad effect upon the troops, some of whom were already dispirited by the storm of the horn-work.
The original plan being now resumed, the hollow way from whence the escaladers had advanced, running along the front of defence, was converted into a parallel, and the trench made deep and narrow to secure them from the plunging shot of the castle. Musketeers were also planted to keep down the enemy’s fire. But heavy rains incommoded the troops, and the French raised a palisaded work on their own right, which flanked this parallel, and from thence they killed so many of the besiegers’ marksmen that the latter were withdrawn.
In the night a flying sap from the right of the parallel was pushed within twenty yards of the first line; but the directing engineer was killed, and with him many men, for the French plied their musketry sharply, and rolled large shells down the steep side of the hill. The head of the sap was indeed so commanded as it approached the wall, that a six-feet trench, added to the height of the gabions above, scarcely protected the workmen; wherefore the gallery for a mine was worked as rapidly as the inexperience of the miners would permit.
When the secret battery in the horn-work of San Michael was completed two eighteen-pounders were removed from the first battery to arm it, being replaced by two iron howitzers. The latter were used to drive the French marksmen from their offensive palisaded wall, but after firing one hundred and forty rounds without success the attempt was relinquished; and ammunition was so scarce that the soldiers were paid to collect the enemy’s bullets.
A zigzag was now commenced in front of the first battery, down the face of San Michael, to obtain footing for a musketry trench to overlook the enemy’s defences below: the workmen were exposed to the whole fire of the castle at the distance of two hundred yards, and were knocked down fast, yet the work went steadily on.
On the 26th the gallery was advanced eighteen feet and the soil found favourable; but the men, in passing the sap, were hit by the French marksmen, and an assistant engineer was killed. In the night the parallel was prolonged on the right to within twenty yards of the ramparts, in the view of driving a second gallery and mine; musketeers were then planted there and at the same time the zigzag was continued, and the musket trench completed with little loss, though the whole fire of the castle was concentrated on the spot.