The Spaniards had pierced the walls with embrasures for their cannon, and these commanded all the avenues. The gunners waited until the columns were close at hand, and then their terrible discharge swept lanes through the crowded masses in the streets. For a moment the Mexicans paused, paralyzed by the terrible slaughter; and then, rallying, rushed forward again. Three times the cannon were discharged into their midst; but though broken and disordered, they still pressed on until they swept up to the very foot of the walls, pouring in a hail of arrows. They were well seconded by those on the housetops who, from their elevated position, were on a level with the Spaniards; and whose missiles, arrows, javelins, and stones thrown with great force from slings, galled the defenders greatly, and wounded great numbers of them. In vain did the Aztecs strive to climb the walls. These were of no great height but, as they showed their heads above the parapet, they were shot down by the Spanish arquebus men, or struck backwards by the weapons of the Tlascalans. Failing to scale the walls, they tried to batter down the parapet with heavy pieces of timber. But the stonework was too strong, and they then shot burning arrows into the palace, and hurled blazing torches over the wall. The palace itself was of stone, but some of the exterior works which had been constructed were of wood, and these were soon on fire. The defenders had no water with which to extinguish the flames and, at the point where the new works joined the wall, the fire was so fierce that they were afraid it would spread to the palace; and, to extinguish it, were forced to adopt the desperate expedient of overthrowing the wall upon the burning mass. The breach thus made was guarded by a battery of heavy guns and a party of arquebusiers, and these repelled every attempt of the Mexicans to take advantage of the breach which had been thus formed. The fight continued until night fell, and the Mexicans then drew off. Cortez and his followers were astonished at the obstinacy with which they had fought, and the contempt of death they had displayed. They had obtained such easy victories, with forces but a fourth of those which Cortez now commanded, that he had formed the lowest opinion of the fighting powers of the Aztecs. But he now found that a nation was not to be trampled upon with impunity. However, he consoled himself with the thought that this was but a temporary outbreak of fury; and he determined to sally out with all his force, on the following morning, and to inflict a terrible chastisement upon his assailants.