“But they may run into us,” objected Frank. “If they’re moving around down here, and they’ll heat our screws too.”

“Don’t you worry, son,” replied Rawlins. “We’re on hard bottom ten fathoms deep and quiet as a mouse and they’ll be on the surface looking for oil or wreckage. And by glory I’ll bump ’em, as the quarter-master says—that is, if I may, Mr. Pauling.”

“H-m-m,” muttered Mr. Pauling. “I don’t think they’re worthy of any consideration. They evidently tried to destroy us and are no better than pirates. I guess we’ll be perfectly safe in firing on them if necessary. But don’t sink them first thing, Rawlins. Put a shot over them—close enough to let them know we mean business. They can give us valuable information if we capture them, but dead men don’t talk.”

“You bet I’ll show ’em we mean business!” declared Rawlins. “I handled a gun and crew during the war and I bet my bottom dollar I can slam a shell so close to ’em it will take their hats off without rumpling their hair.”

“Oh, I hear that whirring again!” cried Frank excitedly.

“Me too!” added Tom.

Bancroft grabbed the receivers and put them on. For an instant he listened attentively and to his ears came the steady unmistakable swishing whir of a vessel’s screw, the sound Frank had so aptly compared to a heavy wind.

“She’s a-coming!” announced the operator. “Not far off, either!”

Rawlins sprang to the periscope and glued his eye to it, swinging it around throughout the entire arc of its movement.

“Now they’re closer!” cried Bancroft. Then a moment later: “Going off again! Sounds as if they’re circling!”