“I believe you’ve struck the truth, Jerry!” he exclaimed.

“Then it must have been a shooting-star or a piece off a comet,” said Will.

“Not much.  I am sure I heard voices calling out, and laughing over the joke.  I tell you somebody’s playing a nasty trick on us, that’s what!” declared Bluff.

“Voices, did you say?  Are you sure?” demanded Frank, stopping in his fumbling around the tent, while Jerry was throwing some dead palmetto leaves on the fire to induce a speedy blaze, so that they might have more light.

“Yes, I’m sure; and they were out there, too,” continued Bluff, pointing beyond the motor-boat.

“I heard ’em, too!” called Joe, at this juncture, as his head appeared in view above the combing of the craft.

“Out on the bayou?” asked Frank, anxious to solve the strange mystery.

“Sure!  And there was something like the creaking of sails, too.  But I don’t think they was makin’ fun of us.  I kinder thought one of ’em called out somethin’ that sounded like, ‘Help us!’” went on Joe breathlessly.

“Talk to me about your mysteries!  Who ever ran up against a worse one than this?” gasped Jerry, scratching his head, as he shivered in the cool air.

“What time is it, anyhow?” demanded Will, who had now found his camera, and was feeling satisfied, because it did not appear to have sustained any injury.

“Time?  I declare if that isn’t dawn in the east, fellows!  Time we were up, I guess,” remarked Frank, stooping over again, determined to learn the secret of the sudden and violent collapse of the tent, accompanied by such strange whispering voices that seemed to die away in the distance.

“Well, all I can say is that if dawn comes with such a swoop down in this blessed country, it’s me back to my native heath again,” grumbled Jerry, who had received a few bruises in the mix-up.  Up to now he had paid no attention to them, but they were beginning to make themselves manifest.

“What’s this?”

Frank uttered the cry as he bent over and stared at something which he had discovered under the canvas.

“Hold on!  I’ve got my gun handy!” exclaimed Bluff, thinking that if it were a wild animal his time had come to distinguish himself.

“Oh!  What is it?” echoed Will, crowding near.

The fire was now leaping madly up as the tinder-like dried palmetto leaves and stalks caught, so that every one could easily see.

“Why, it’s a bag!—­a big bean bag!” exclaimed Will, in amazement.  “Where, in the name of goodness, did that come from, fellows?”

“A bean bag!  Tell me about that, will you?” said Jerry.  And then, as he bent over to clutch hold of it, he went on:  “Why, as sure as you live, it’s a sand bag!  Who ever could have shied that thing at us and then run away?”

Frank was more than startled.  He had seen just such bags before, and filled with sand, too.  He knew to what uses they were put.