ovoke you to do so. The situation is one calling for tact, Herr
Lieutenant."

"And I cannot forget that you are taking occasion to remind me of the
fact," retorted von Schellen, a dark look coming into his face.

"Then may I, as the prisoner of war, ask that the subject be changed?"
Dave Darrin suggested.

"By all means," von Schellen returned, quickly, though he was able to
perceive that the American had again succeeded in putting him in the
wrong.

Just a moment later a petty officer appeared on deck. Taking two or three
steps toward the junior officer he halted, saluted, and then remained
standing at attention, as though waiting.

Von Schellen stepped over to the man, and a conversation followed in low
tones, but did not last long.

"If you care to remain on deck and watch," said the junior lieutenant,
"you will see something that may interest you."

CHAPTER XII

GERMAN BRUTALITY AT ITS WORST

JUST behind the conning tower a jointed steel mast was raised and stepped
by three seamen who came at the petty officer's order.

Farther astern a narrow, ledge-like trapdoor of steel was raised, and
from this was taken and stepped another steel jointed mast. The seamen
now worked quickly in rigging aerial wires in place. In a very short time
the work was completed, and the petty officer saluted von Schellen.

"You cannot fail to understand what we are doing," hinted the young
German officer.

"You are about to send or receive radio messages, I take it," Dave
replied.

"You have been told, of course, that we always report our whereabouts
after dark?"

"Yes, it is common knowledge with the Allies," Dave admitted. "And also
that you receive instructions from the home offices of your Admiralty."

There was a crackling sound on the aerials, followed by others, some
short, some long.

"A wonderful invention, is it not?" asked von Schellen, with
satisfaction.

"Yes, and first developed outside of Germany," Dave bantered,
good-humoredly.

"True enough, but we have known how to take the radio and adapt it to all
our needs," retorted von Schellen.

"Your operator is now reporting your whereabouts, of course."

"That would seem likely, wouldn't it?" the other demanded.

"And then you will receive information."

"Yes; and sometimes we have even messages for our men from their homes,"
laughed von Schellen. "More! I have even had tender messages from my
sweetheart! And have answered them in kind!"

Fo