The Napoleon battery commanded every thing around it, save to the north, where at the distance of three hundred yards there was a second height scarcely less elevated than that of the fortress. It was called the Hill of San Michael, and was defended by a large horn-work with a hard sloping scarp twenty-five, and a counterscarp ten feet high. This outwork was unfinished and only closedSee [Plan 4.] by strong palisades, but it was under the fire of the Napoleon battery, was well flanked by the castle defences, and covered in front by slight entrenchments for the out picquets. The French had already mounted nine heavy guns, eleven field-pieces, and six mortars or howitzers in the fortress, and as the reserve artillery and stores of the army of Portugal were also deposited there, they could increase their armament.
FIRST ASSAULT.
The batteries so completely commanded all the bridges and fords over the Arlanzan that two days elapsed ere the allies could cross; but on the 19th the passage of the river being effected above the town, by the first division, major Somers Cocks, supported by Pack’s Portuguese, drove in the French outposts on the hill of San Michael. In the night, the same troops, reinforced with the forty-second regiment, stormed the horn-work. The conflict was murderous. For though the ladders were fairly placed by the bearers of them, the storming column, which, covered by a firing party, marched against the front, was beaten with great loss, and the attack would have failed if the gallant leader of the seventy-ninth had not meanwhile forced an entrance by the gorge. The garrison was thus actually cut off, but Cocks, though followed by the second battalion of the forty-second regiment, was not closely supported, and the French being still five hundred strong, broke through his men and escaped. This assault gave room for censure, the troops complained of each other, and the loss was above four hundred, while that of the enemy was less than one hundred and fifty.
Wellington was now enabled to examine the defences of the castle. He found them feeble and incomplete, and yet his means were so scant that he had slender hopes of success, and relied more upon the enemy’s weakness than upon his own power. It was however said that water was scarce with the garrison and that their provision magazines could be burned, wherefore encouraged by this information he adopted the following plan of attack.
Twelve thousand men composing the first and sixth divisions and the two Portuguese brigades, were to undertake the works; the rest of the troops, about twenty thousand, exclusive of the Partidas, were to form the covering army.
The trenches were to be opened from the suburb of San Pedro, and a parallel formed in the direction of the hill of San Michael.
Jones’s Sieges. A battery for five guns was to be established close to the right of the captured horn-work.
A sap was to be pushed from the parallel as near the first wall as possible, without being seen into from the upper works, and from thence the engineer was to proceed by gallery and mine.
When the first mine should be completed, the battery on the hill of San Michael was to open against the second line of defence, and the assault was to be given on the first line. If a lodgement was formed, the approaches were to be continued against the second line, and the battery on San Michael was to be turned against the third line, in front of the White Church, because the defences there were exceedingly weak. Meanwhile a trench for musketry was to be dug along the brow of San Michael, and a concealed battery was to be prepared within the horn-work itself, with a view to the final attack of the Napoleon battery.
The head-quarters were fixed at Villa Toro, colonel Burgoyne conducted the operations of the engineers, colonel Robe and colonel Dickson those of the artillery, which consisted of three eighteen-pounders, and the five iron twenty-four-pound howitzers used at the siege of the Salamanca forts; and it was with regard to these slender means, rather than the defects of the fortress, that the line of attack was chosen.