“Be careful, is all I ask you, Sandy,” Bob replied. “They tell us the currents of the Mississippi are treacherous, and that they often clutch a swimmer as if they had many hands. If the boat starts down-stream again, as I fancy may be the case, I will follow along the shore, bearing both guns.”

Sandy hastened to divest himself of all superfluous clothing, at the same time keeping one eye on the strange boat.

He was a splendid swimmer; indeed, the boy had ever been like a duck in the water, so that Bob felt little fear about his ability to reach the boat, and tow it ashore, unless some unexpected development occurred.

“Keep out of range as you draw closer, Sandy,” he remarked.

“What makes you say that, Bob?” demanded the other. “It sounds as if you expected to have to use your gun. Come, do you think Indians might be lying in the bottom of the boat, ready to rise up and seize a swimmer, if he came close; or fill him full of arrows?”

“Here is a tree that I can easily climb,” remarked Bob. “Wait a minute while I get up among the branches. Perhaps I can tell then if enemies are crouching in that boat. Don’t start till I come back, Sandy.”

He climbed like a monkey, and was quickly in a position where he could take a partial view of the strange craft’s interior.

But Bob did not stay there long. Whatever it was he saw, he dropped down again to the ground much faster than he had climbed aloft.

“Did you see any Indians?” asked Sandy, now ready to plunge into the water.