The captain shook his head.

“I don’t believe it was an accident. We have always been mighty careful about leaving any waste around where it could start into a flame. Besides, if you notice, boys, you can see that it started close to the cabin, and not near the boiler.”

Captain Amos involuntarily lowered his voice and glanced suspiciously around while speaking. His manner thrilled the boys as they had seldom been before.

“Not an accident! Tell me about that, will you? Do you mean that you believe some one set the boat afire?” exclaimed Jerry.

“Don’t speak so loud, please. That is what I think. Unless it was intentional, I can’t imagine how the thing started,” answered the young captain, who was still much excited after his recent experience.

“But it seems monstrous. Who would be guilty of such a terrible thing?” asked Frank, possibly dimly suspecting that the other might be seeking to cover up some lack of proper caution on his part, though that was not like Amos Short.

“Say, did your crew mutiny?” gasped Bluff, whose eyes were wide open with wonder over this new development of the affair, and who had lately been doing considerable reading of sea tales.

“Well, hardly. I only have the engineer, an old faithful fellow; the pilot, who stuck to his post through it all, and would have run us ashore if the worst came; and one deck hand, a darky,” he replied warmly.

“Then it was a passenger, you think?” demanded Frank, determined to get at the bottom of this new mystery.

“Well, none of my pay passengers. Listen and I’ll tell you. This being the first trip this year we were not so particular about taking pay. At Newtonport a couple of tramps got aboard. When I went to collect their fares they said they had no money, but wanted to get across the lake to Centerville. Rather than have a disturbance on board I allowed them to remain, cautioning them to stay below near the engine.”