Up the rifle came, but, just as he pressed the trigger, Professor Scotch pushed the weapon to one side, so the bullet did not pass within twenty feet of the white canoe.
"Why did you do that?" demanded Frank, angrily.
"I couldn't see you shoot into that canoe again," faltered the agitated professor. "It was too much—too much!"
"What do you mean by that?"
Professor Scotch shook his head. He could not explain, and he was ashamed of his agitation and fears.
"Well, you fellows lay over anything I ever went up against!" said Frank, in disgust. "I didn't suppose you could be so thoroughly childish."
"All right, Frank," came humbly from the professor's lips. "I can't help it, and I haven't a word to say."
"But I will take one more shot at that canoe!" vowed Frank.
"Not this day," chuckled Barney Mulloy. "She's gone!"
It was true. The mysterious canoe had vanished from view while they were speaking.