This day also a zigzag was commenced in front of the first battery and down the face of San Michael, to obtain footing for a musketry trench to overlook the enemy’s defences below; and though the workmen were exposed to the whole fire of the castle, at the distance of two hundred yards, and were knocked down fast, the work went steadily on. On the 26th the gallery of the mine was advanced eighteen feet, and the soil was found favourable, but the men in passing the sap, were hit fast by the French marksmen, and an assistant engineer was killed. In the night the parallel was prolonged on the right within twenty yards of the enemy’s ramparts, with a view to a second gallery and mine, and musketeers were planted there to oppose the enemy’s marksmen and to protect the sap; at the same time the zigzag on the hill of San Michael was continued, and the musket trench there was completed under cover of gabions, and with little loss, although the whole fire of the castle was concentrated on the spot. The 27th the French were seen strengthening their second line, and they had already cut a step, along the edge of the counterscarp, for a covered way, and had palisaded the communication. Meanwhile the besiegers finished the musketry trench on the right of their parallel, and opened the gallery for the second mine; but the first mine went on slowly, the men in the sap were galled and disturbed, by stones, grenades, and small shells, which the French threw into the trenches by hand; and the artillery fire also knocked over the gabions of the musketry trench, on San Michael, so fast, that the troops were withdrawn during the day. In the night a trench of communication forming a second parallel behind the first was begun and nearly completed from the hill of San Michael towards the suburb of San Pedro, and the musketry trench on the hill was deepened. The 28th an attempt was made to perfect this new parallel of communication, but the French fire was heavy, and the shells, which passed over, came rolling down the hill again into the trench, so the work was deferred until night and was then perfected. The back roll of the shells continued indeed to gall the troops, but the whole of this trench, that in front of the horn-work above, and that on the right of the parallel below, were filled with men whose fire was incessant. Moreover the first mine was now completed and loaded with more than a thousand weight of powder, the gallery was strongly tamped for fifteen feet with bags of clay, and all being ready for the explosion Wellington ordered the THIRD ASSAULT.