There was a long and ominous pause before the next renewal of conflict. Wellington used it to repair his shattered left and brought in Lambert's Peninsular veterans, twenty-two hundred strong. Napoleon quickly formed a corps, under Lobau, intended to repel the flank attack of the Prussians. Ney was determined to redeem his repulse by a second front attack, and Napoleon, either by word or silence, gave consent. While the batteries kept up their fire, the marshal gathered in the center the largest mass of horsemen which had ever charged on a European battle-field--twelve thousand men, light and heavy cavalry. His aim was to supplement Reille, still engaged at Hougomont, and dash in upon the allied right center. Donzelot's column, now reformed, was hurled directly against La Haye Sainte, and the mass of the cavalry surged up the hill. The gunners of Wellington's artillery, unprotected even by breastworks, stood to their pieces until the attacking line was within forty yards; then they delivered their final salvo, and fled. Wavering for an instant, the French advanced with a cheer. Before them stood the enemy in hollow squares, four ranks deep, the front kneeling, the second at the charge, the two others ready to fire. The horsemen dared not rush on those bristling lines. In and out among the serried ranks they flowed and foamed, discharging their pistols and slashing with their sabers, until, discouraged by losses and exhausted by useless exertion, their efforts grew feeble. Dubois's brigade, according to a doubtful tradition, dashed in ignorance over the brow of a certain shallow ravine, men and horses rolling in horrid confusion into the unsuspected pit. The hollow was undoubtedly there at the time, although it has since been filled up, and, it is believed, was likewise the grave of the fifteen hundred men and two thousand horses that were eventually collected from round about. The British reserve cavalry, supported by the infantry fire and a few hastily collected batteries, completed the defeat of Ney's first charge. A second was repulsed in the same way. The undaunted marshal then waited for reinforcements. No fewer than thirty-seven squadrons came in, Napoleon sending Kellermann's heavy dragoons as a last resort. Guyot's division of the heavy cavalry of the guard was also there--some say they had been summoned by Ney, others that they came of their own accord; the question arises because, in the next stage of the battle, their absence from the station assigned to them was a serious matter. Another time, and still another, this mighty force moved against the foe. Pouring in and out, backward and forward, among the squares, they lost cohesion and force until, in the very moment of Wellington's extremity, they withdrew, as before, exhausted and spent.