"You should have known you couldn't convince him," said Jack.
The three friends walked along the deck gazing out over the water. Half an hour later, as they were about to go below, Frank caught sight of a figure in the uniform of a German lieutenant, who was eyeing them closely.
There was something familiar about that figure and unconsciously the lad gave a start. He called Jack's attention to the man, and the latter, seeing that he was the subject of discussion, quickly withdrew.
"I've seen him some place," said Frank.
"And so have I," Jack declared. "There is some thing strangely familiar about him. Say! It's unpleasant when you know a man and can't place him."
"Let's hope he is not some old enemy come back to life," said Frank, quietly, as they returned to their cabin.
CHAPTER XXIII
AN UNKNOWN FRIEND
Bremen. The greatest of all German shipping centers, and, before the outbreak of the European war, one of the greatest seaports in the whole world.
Even on the third day of June, 1916, when the German warship on which Jack, Frank and Harris were prisoners steamed into Bremen the port was alive with activity. Great German merchant ships, useless since the war began, appeared deserted, but other and smaller craft dashed hurriedly hither and yon.