"We must have landed right over a mine cargo once more," Dave answered smiling. "There were several explosions, but they came nearly together. One of these days we'll start something like that that will send us up half a mile into the air. But it's great sport, Andrews, especially when you pause to think what it all means."

"Great sport for us, but too sudden for the Huns," rejoined the watch officer. "They cannot have had the satisfaction, even, of realizing that anything had hit them."

Satisfied that there would be no more underseas explosions, Darrin gave the order to come about.

That the underseas craft had been struck was indicated clearly enough by the patches of oil on the water. The force of the explosion told the Yankee tars that the craft must have been blown into bits.

"Best thing I ever saw done!" signalled the British officer in command of the "blimp."

"Find us another, and we'll try to show you something just as good," Darrin caused to be signalled back.

Fernald, who had been called, having reported, was sent with the chief engineer to make a hull inspection below decks. Though some of the hull plates had been dented inward enough to attract attention, no leak could be found. The "Grigsby" was as seaworthy as ever, though after that rocking shock this seemed a marvel.

Off in the distance the "blimp" soon became a mere speck to the watchful eyes of those on the destroyer.

Dave directed that the aircraft be followed at cruising speed so long as she remained in sight. When the dirigible was at last lost to view the destroyer lay to, her lookouts using their glasses.

"Think the aircraft is coming back, sir," reported a lookout from the military mast.