They were just getting up from supper when they heard a tremendous racket close by. There was a crash, and a splash, as though a whole section of the river bank had caved in. “The big tree!” exclaimed Will, turning white. “I wonder, now,” remarked Jerry, rather in doubt; while Bluff declared he meant to go ashore, and find out if it could really be so. He came back later, lantern in hand, and reported that the tree, to which they had thought to tie up, had entirely disappeared, having been undermined by the rising flood, so that it toppled over into the river, and was carried off. Where it had once proudly stood, there now remained only a gap in the river bank. And once again did three of the chums have reason to be thankful for Frank Langdon’s thoughtfulness. What their fate might have been had they carried out their first intention, was not pleasant to contemplate. During the night another heavy shower fell, and for an hour the rain pattered upon the roof of the houseboat. Frank declared, in the morning, that this sort of weather in the summer was a rare thing; for, as a rule, the rivers are at flood in the early spring, and decline through the hot months. “See any chickens roosting on a floating coop, Bluff?” asked Jerry, at one time during the morning, as he noticed the other handling the glasses nervously. “Frank, oh! Frank, look here!” called Bluff, without paying any attention to the joking words of the other; and as Frank came hurrying out of the cabin Bluff went on to say: “take a look, and see what you make of that tree down there, that we’re catching up with. Seems to me there’s people in the branches!” Instantly there was excitement aboard the houseboat. Frank peered through the glasses, and immediately confirmed the words of the discoverer; and as the others, in turn, took a look, they added their opinions. “A man, a woman, and, seems to me, two children, are perched among the branches of the tree,” Frank continued, soon afterwards, as he looked again; “and as the thing seems to be moving very slowly we’re catching up, all right.” “But how in the wide world d’ye suppose they ever got there?” demanded Will. “Their house may have been carried off; and, finding that it was sinking, they climbed into that treetop when they had the chance. Now, I recollect I _did_ hear a call just before morning. I listened, and made up my mind it was only a wild bird, perhaps a night-heron hunting its food along the flooded bank. But it must have been one of those children crying in fear!” “Well, we’ve sure got to get that family aboard, and take them to the next town. Why, perhaps those children are half starved for something to eat right now!” Jerry remarked, warmly, for he knew what that must feel like.