eel and stalked
away. Frank gazed after him amusedly.

"Now what do you think of that?" he exclaimed.

"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.

"Why all the excitement?" was Frank's comment, as the three stood well
forward while the warship steamed through the harbor.

"Several reasons, I guess," said Jack. "One is that half of these small
vessels ply between Bremen and Scandinavian ports in spite of the
British blockade; and the other reason probably is the fact that the
city is celebrating the great naval victory."

"Naval victory?"

"Sure; the battle of Jutland. The German people have been told that the
German fleet won; and now the people are celebrating. See all those
flags? Why else would they be displayed so profusely?"

"Because Germany is at war," said Frank.

"Oh, no they wouldn't. You remember we were in Hanover once while the
war was in progress. You didn't see all those flags about like that."

"I guess you're right."

At that moment a German officer approached the three friends.

"I've something of interest to show you," he said; "something that will
be of interest to all the world presently."

"We shall be glad to see it, whatever it may be," replied Jack,
courte