“My idea, too, sir,” agreed Frank.

Lord Hastings turned on his heel and left the compartment, and a moment later the vessel began to sink lower and lower into the sea. Frank still stood on watch, and when he was certain that the D-16 would pass beneath the mine without danger of striking it, he gave the signal and the vessel headed forward once more.

Lord Hastings entered the compartment again.

“The chances are there are more of them,” he said, “so we shall have to be very careful. I’ll have Mr. Templeton take the next watch, for we cannot keep too sharp a lookout.”

Frank nodded his head in assent. Lord Hastings left.

Five minutes later Jack appeared at Frank’s side and the latter turned to go. Suddenly he whirled about and spoke to his chum.

“You must be more careful than I was,” he said quietly. “I was almost the means of sending us all to the bottom for good.”

“What do you mean?” asked Jack in surprise.

Frank explained.

“Well,” said his chum consolingly, “a miss is as good as a mile, you know.”