"We are as close as we can get now," said Teotlili, touching him on the arm. "We had better wade ashore and run to the city, for their horsemen might attempt to cut us off. Hark! I hear sounds of fighting." They stood up in the canoe and listened, the noise of some conflict coming to their ears. "The first attack on the causeways," said Roger. "We need have no fear of the enemy breaking in while we are absent. But we had better run, for, as you say, the Spaniards might send out their horse to cut us off. Let the men keep together." They stepped into the water, and waded across the mud-flats till they reached dry ground, the Mexicans dragging their canoes after them. Then all set their faces toward Mexico, where they arrived within half an hour. They found each of the three Spanish divisions hotly engaged on the causeways, and hastened at once to aid in the defence, the arrival of Roger being hailed with loud shouts of triumph. "The cacique has come," the men bellowed to one another. "Here is the fighting chief who has promised to lead us. We will show these Spaniards what we can do." Men rushed out and picked the young giant up in their arms. Then he was borne to the main causeway, to where the King of Mexico was stationed. "I am glad that you have come," said the latter, grasping his hand warmly. "I am lost without you. You know these men against whom we fight, and you are able to meet their strategy with methods which are new to us. Come to the edge of the breach and see what is happening." They walked along the causeway to that part which faced the far shore, and was within a stone's throw of it. A wide breach had been made, on the near side of which the Mexican crossbow-men were posted, while on the far side stood the Spaniards, baulked for the moment, and viciously plying the defenders with a hail of shot and cannon-ball. The attack had commenced, in fact--an attack which was to develop, and which was to be of unparalleled ferocity. CHAPTER XVIII The Defence of the Causeways The siege of Mexico had commenced in earnest, for now that the fleet of canoes had been scattered or sent to the bottom, the brigantines closed in on the fair city which lay on the bosom of the lake, till the long, straight causeway stretching north and south prevented further progress. And there the cannon were turned upon the defenders who manned the wide strip of masonry, while from the farther side of the breach other cannon belched forth shot at them. But this was not all. At two other and separate points the Spaniards had made an incursion on to the causeways, all of which led to the city, so that three parties of Mexicans were kept engaged, and their whole force posted on the main portion of the viaduct was exposed to the flanking fire of the brigantines.