The lances were within four yards of him when he thrust the match into the black train trailing across the deck. But even then his coolness and determination did not desert him. He pushed in the glowing end and waited till the grains commenced to splutter. Then he tossed the brand full at Roger, and setting the example to his men, leaped over the side, the Spaniards following instantly, tumbling into the lake with a series of loud splashes, and with loud shouts to attract the attention of their comrades. As for the attackers, the Mexicans hardly realized what was happening, for they were unacquainted with the powers of gunpowder, and even then, after their conflicts with the Spaniards, did not know how the thunder of their guns was produced, nor the means by which the ball was driven. They stared over the side, therefore, while the crossbow-men sent their shafts at the swimmers. And there they would have remained, deafening the air with their shouts of triumph, had it not been for their leader. Roger bounded forward and leaped at the spluttering train, hoping to put out the fire with his foot. But it ran as swiftly as a man could travel, and as he reached the black and smoking line which it had left, he saw that it was already descending the rough ladder which led below, and was racing over the piece of canvas on which Alvarez had laid it. Beyond, in the darkness, which the flashes of the powder helped to lighten spasmodically, was the faint outline of a barrel. "The powder! We are dead men if we do not leap overboard!" he shouted. Then he seized Teotlili and dragged him to the side. "Tell all to leap at once for their lives," he said. "Come, Philip, Peter, and every one. We will capture Alvarez in the water." There was not a moment to be lost, and therefore, without another glance at those aboard, he flung himself into the water, and swimming beneath the surface as far as possible, rose at length when he was forced to do so by the need of air. At the same instant there was a deafening explosion, the brigantine split into fragments, while her deck and spars, together with some dozen of the unhappy natives, were flung into the air with terrific force, the _débris_ descending within a few seconds, and splashing into the lake. Roger trod water and looked vainly for Alvarez. But he was nowhere to be seen. Then he turned to look for Peter and Philip, to find them close behind him. "The enemy are being picked up by that brigantine," gasped Philip, pointing to one which was close at hand. "We had better move away, or they will take us prisoners." "Or shoot us down with their shafts," spluttered Peter, who was no great swimmer. "Better get aboard one of the canoes." "We must do so at once," answered Roger. "Alvarez must escape for the time, but I know that he is with the enemy now, and that he has the disc. Let him wait, for I will take him yet, and make him pay for his treachery. Ah, here is Teotlili."