on deck for fresh air
before you are interviewed by Herr Kapitan Schwalbe. See that door?
Beyond that you must not pass without permission. It is forbidden. If
you do so, you will not have another opportunity in a hurry."

"What are they going to do with us?" asked Ross.

The sailor shook his head.

"It is forbidden to ask questions," he said sternly. "Whatever is
necessary that you should know will be told you."

He turned his back upon his questioner, signifying in a plain manner
that it was useless for Trefusis to say more. Taking the hint the lad
returned to his chum, wondering deeply at the fate that had thrown them
into the hands of the enemy.

CHAPTER V

Aboard U75

Like Ross, Vernon Haye made a poor meal. He had barely finished when a
petty officer appeared and curtly ordered the lads to follow him.
Since he did so in German it was fairly certain that Trefusis'
admission had been communicated to both officers and crew.

Staggering, they passed along the alley-way into a broad subdivision
that extended completely athwartships. It was one of the two broadside
torpedo-rooms, and contained two tubes of slightly greater diameter
than the British 21-inch. In "launching-trays" by the side of the
tubes were eight torpedoes with their deadly war-heads attached. Both
transverse bulkheads were almost hidden by indicators, voice-tubes, and
pipes for transmitting the compressed air from the air-flasks to the
torpedo-tubes.

Passing through another water-tight door the prisoners found themselves
in yet another compartment. On one side was an "air-lock", with its
complement of life-saving helmets; on the other was an oval-shaped door
forming means of communication with the small room built against the
curved sides of the submarine. Ross guessed, and rightly as it
afterwards transpired, that the door led into a space that could be
flooded at will, and which in turn enabled a diver to operate from the
U-boat while submerged.

Confronting the lads was an almost perpendicular steel ladder
communicating with the conning-tower. Their guide was about to ascend
when a stern voice exclaimed in German:

"Not that, you idiotic clodhopper! Have you lost your reason? The
forward hatchway, don't you know?"

"Pardon, Herr Leutnant," said the petty officer, abjectly apologetic,
and, backing down the ladder, he passed through another door entering
into an alley-way between the officers' cabins. Here was th