Roger's quick eye had seen the same bag in which he had brought the golden sign ashore now secured over Alvarez's shoulder, and doubtless containing the coveted disc--the plaque which held the secret of the Mexican treasure, and which, if he could only secure it, would lead to an immense reward for himself and the expedition; that is, supposing he and his comrades escaped from Mexico, which was not at all certain. In the meanwhile they had their hands sufficiently full, for as they fought on the deck of the Spanish brigantine, the other vessels sailing beneath the flag of Castile bore down upon them, churning their way through a mass of canoes, which were swamped for all the world as though they were but tiny shells. None of the Mexican craft could withstand these heavy vessels--not even those constructed by Peter Tamworth. The huge prows of the brigantines crashed into them and bore them down, rolling them and their freight over, and sending the canoes to the bottom. The natives, however, could swim like fish, and while numbers made vain attempts to clamber aboard the brigantines, others swam to their comrades or turned for the long swim home. But they had to contend with more than water alone, for as the brigantines ran, the Spanish plied the enemy with their guns, using small shot, one of which was sufficient to wreck a canoe, while broadsides often slew fifty and more of the unfortunate Mexicans. Then the crossbow-men aboard turned to the brigantine on which Roger and his friends fought, sending their shafts amongst them. "Tell some of our men to keep down that fire," gasped Roger, halting for a moment and turning to Teotlili. "Now, Peter and Philip, one more effort and we will drive these Spaniards out into the lake. Shoulder to shoulder, and bring up some of the natives with the lances. We will make a capture, and will take this fellow Alvarez; for see, the disc is hanging to his shoulder."