To find themselves once more in their canoes, and to be gliding over unknown waters, with new scenes unfolding at every turn, was so exhilarating to the boys that they started up the river at racing speed, shouting and laughing as they went. They were about to disappear from the sight of the others around a bend of the stream when they were checked by a shout from Lieutenant Carey. As he joined them he said:
"We must keep together, boys, and regulate our speed by that of the cruiser, for, in case of unforeseen difficulties or dangers, it won't do for us to be separated. I wouldn't make any more noise than is necessary either. There is no knowing what the Indians, whose country we are entering, may take it into their heads to do. While I do not anticipate any serious trouble from them, I would rather avoid them as much as possible, and by proceeding quietly we may escape their notice—at least for the present."
For the first mile or two the river-banks were hidden beneath a dense growth of mangroves, though above these they could catch occasional glimpses of the tops of pines and tall palmettoes. The mangroves grew smaller and thinner, until finally they disappeared entirely, and on tasting the water over which they floated our voyagers found it to be fresh and sweet.
"There is no danger of our suffering from thirst on this trip whatever may happen," said Sumner.
They were close to one of the banks as he spoke, and from it there suddenly came a rushing sound, followed by the floundering splash of some huge body in the water, so close at hand that their canoes were violently rocked by the waves that immediately followed. The suddenness of the whole proceeding drew a startled cry from Worth.
"What could it have been?" he asked in a low tone, and with a very white face. "Was it a hippopotamus, do you think?" He had seen the "hippos" splash into their tank in Central Park.
"Not exactly," laughed Sumner, who, after a slight start, had quickly regained his composure. "It was a big alligator, and he went so close under my canoe that I could have touched him with the paddle."
"Suppose he had upset us?"