It was well towards noon when Billy rose from the ground and strolled lazily down to the beach.  Suddenly his good-natured face took on a startled look as he stared anxiously toward the houseboat.  A moment later he was running toward the tent at full speed.

“Fellows, come out here!” he shouted.  “Hurry up!”

“What’s the matter?” asked George Baker, hurrying out of the tent, the other members of the Tramp Club at his heels.

“Look!” gasped Billy, pointing toward the “Red Rover.”  “What do you make of that?”

“Why—­why—­” stammered George Baker.  Then he uttered a sudden cry of alarm.  “By George, she’s on fire.  That scamp has sneaked in and set fire to the boat under our very noses.  I’m positive that he did it.  Pile into the launch with all the pails you can find and let’s get out there.  That villain must have swum over, climbed aboard, and set fire to the side of the boat away from the shore.  That’s why we didn’t notice the smoke when she first began to burn.”

By the time they were on their way toward the doomed houseboat the fire had made tremendous headway.  Being an old boat, the “Red Rover” burned like kindling.  It seemed to be fairly wrapped in flames.

“It’s no use,” groaned George.  “She’ll be gone inside of the next five minutes.  We can’t save the boat or anything on board.  I’m thankful the girls were all on shore.  That villain must have watched them go, and then swam out here.  If he’d paddled out in his canoe this morning we’d have seen him.  Don’t go too near her, fellows.  She’s likely to collapse any minute.”

“Look out!  She’s going!” exclaimed Larry Goheen.  A moment later the whole top of the unwieldy boat fell in, while the flames attacked the hull with renewed fury.

* * * * *

When the Meadow-Brook Girls returned to the shore of the lake, that afternoon, well laden with the fruits of their shopping, they were met by the members of the Tramp Club, who looked unduly solemn.  One glance at their grave faces and Harriet cried out apprehensively, “What on earth has happened to you, boys?”

“We’re all right,” stammered George, “but the ’Red Rover’—­well, it is—­”

The Meadow-Brook Girls all looked involuntarily in the direction of where the “Red Rover” had lain that morning.

“Why—­why—­where is our boat?” faltered Miss Elting.

Then George poured forth the story of the morning’s disaster, while the girls listened in consternation to the recital of the way in which the houseboat had been set fire to and sunk.

“Of course that half-breed did it,” concluded George, “and now that we’ve told you all about it, we are going to start out after him.  I’ll wager he’s somewhere around this lake yet.”

“I shall go back to the village at once and put the matter in the hands of the constable,” declared Miss Elting.  “I shall also see Dee Dickinson.  I hold him indirectly responsible for all the disagreeable things that have happened to us, and for this, too.”