"What is it, Sam?" called Fred.
Sam, however, made no response and soon disappeared from sight around the bend in the shore.
"What do you suppose the trouble is?" inquired John.
"I'm telling you," said George, "that Sam has seen something that surprised him. He has been saying all the while that he was afraid something might happen to the Black Growler."
"But nothing can happen to her to-night. It's perfectly clear. There's no storm, and even Sam did not think it was worth while to run her into the boat-house."
"That may be just the trouble," suggested Grant.
"I don't know what you mean," retorted George, quickly turning upon his friend. "What might happen?"
"The thing that Sam seemed to be afraid of."
"But what is that?"
"Sam hasn't told me."