“Do you know, that occurred to me,” put in Bob. “But I didn’t like to say anything for fear you’d laugh at me. It seemed as if he was afraid we had discovered something.”

“That’s the way I took it,” spoke Ned. “I wonder what it could have been.”

“Whatever it was, you can depend on it there was something crooked back of it,” commented Jerry. “Those two never got together but they were up to some mischief. I only hope we have no further trouble with them.”

The boys were again at the boat house the next afternoon. Ned had asked to run the engine, and, as it was decided that all three should take turns at managing the different parts, Bob went to the wheel while Jerry played he was a passenger.

“Down or up?” asked Bob, as he threw in the clutch and backed the Dartaway out of the house.

“Let’s go down,” suggested Jerry. “Then we can try her up against the current and see how she behaves.”

The boat was making good progress, the engine was purring like a contented cat, and the boys were beginning to enjoy the run, when Bob suddenly shut off the power and cried:

“There, I forgot all about ’em!”

“What?” asked Jerry anxiously. “There’s plenty of gasolene, I hope.”