"So long! We will see you in the morning," called George as they pushed the rowboat off.
"Yes. In the morning—maybe," answered Harriet laughingly.
"It's my opinion that those girls are going to try to play more tricks to-night," declared Billy, after they had gotten a short distance from the "Red Rover." He was speaking in a tone louder than he imagined. Harriet heard every word he said.
"Yes," agreed George. "I'll tell you what we'll do. We'll put a boy on watch to-night. Then, if they try to run away from us, we will just follow and give them a surprise. We can't let those girls get the better of us this time."
That was the last that Harriet heard. They had rowed so far away that their words were inaudible. But what she had heard was quite sufficient.
"And about those ghosts?" questioned Larry.
"A bluff," scoffed George. "You don't believe in ghosts, do you?"
"Well, I don't know. I have heard of such things," admitted Larry solemnly.
"Nonsense. I guess we will elect you to watch the houseboat to-night. How about it?" demanded George.
"I don't care."