The 1st of February the breach in Saint Augustin, also, became practicable, and the attention of the besieged being drawn to that side, the French sprung a mine which they had carried under the wall from the side of Saint Monica and immediately entered by the opening. The Spaniards thus unexpectedly taken in the rear, were thrown into confusion and driven out with little difficulty. They, however, rallied in a few hours after and attempted to retake the structure, but without success, and the besiegers animated by this advantage broke into the neighbouring houses and, at one push, carried so many as to arrive at the point where the street called the Quemada joined the Cosso, or public walk. The besieged rallied, however, at the last house of the Quemada, and renewed the combat with so much fury that the French were beaten from the greatest part of the houses they had taken, and suffered a loss of above a hundred men. On the side of San Engracia a contest still more severe took place; the houses in the vicinity were blown up, but the Spaniards fought so obstinately for the ruins that the Polish troops were scarcely able to make good their lodgement--although two successive and powerful explosions had, with the buildings, destroyed a number of the defenders. The experience of these attacks induced a change in the mode of fighting on both sides. Hitherto the play of the French mines had reduced the houses to ruins, and thus the soldiers were exposed completely to the fire from the next Spanish posts. The engineers, therefore, diminished the quantity of powder that the interior only might fall and the outward walls stand, and this method was found successful. Hereupon the Spaniards, with ready ingenuity, saturated the timbers and planks of the houses with rosin and pitch, and setting fire to those which could no longer be maintained, interposed a burning barrier which often delayed the assailants for two days, and always prevented them from pushing their successes during the confusion that necessarily followed the bursting of the mines. The fighting was, however, incessant, a constant bombardment, the explosion of mines, the crash of falling buildings, clamorous shouts, and the continued echo of musquetry deafened the ear, while volumes of smoke and dust clouded the atmosphere and lowered continually over the heads of the combatants, as hour by hour, the French with a terrible perseverance pushed forward their approaches to the heart of the miserable but glorious city.