"May he go to defeat if he tries it!" said Jack fervently.
"In which case," said the lieutenant with good natured tolerance, "you would undoubtedly go with us."
"Even so," replied Jack, "I still could not wish to see you get away."
The lieutenant glanced at him admiringly.
"I believe you mean it," he said. "You are a brave lad. But come, we had all better turn in now."
"I guess you are right," said Frank; "and thanks for the trouble you have taken to explain all this to us."
"It was a pleasure, I am sure," was the lieutenant's reply, and they all made their way to the officer's cabin, where they prepared to retire for the night.
CHAPTER V
UNDER THE SEA
But there was to be no sleep for any aboard the German submarine X-9 that night. As the boys were just about to tumble into their bunks, there was the sound of a sudden commotion on the vessel.