ment on the oily swell, was a welcome one.

The lads had set their joint watch by the submarine's time, which,
being mid-European standard, was one hour fast of Greenwich.

For several hours they slept soundly and undisturbed. Suddenly they
were both awakened by the muffled tramp of men in heavy sea-boots. The
solitary light in the alley-way was switched off; the water-tight doors
were firmly closed. Already the air in the confined space was stifling.

"What has happened?" asked Vernon anxiously, for the vessel, instead of
resting immovably upon the bed of the channel, was now rolling
sluggishly. Yet she could not be under way, for the motors were silent.

Springing from his bunk, Ross felt for the switch of the electric
light. It was already down, yet the flow of current was interrupted.

"Let's find out," he said. "Come along."

The lads, before turning in, had carefully laid out their clothes, so
as to be ready to slip into them at a moment's notice, yet it was a
matter of considerable difficulty to dress in the dark.

"The door's closed," announced Ross as the lads groped their way to the
end of the alley-way.

"I believe the submarine's holed," suggested Haye.

"No; she wouldn't lift as she's doing. Besides, the crew are moving
about. Let's bang on the door with our boots."

For several minutes they hammered, but without result. The air, never
very fresh, was now almost unbearable, owing to lack of ventilation.
The imprisoned youths began to get desperate.

Then, without warning, the door slid back. The alley-way was flooded
with brilliant light.

"Make haste!" shouted a voice which the lads recognized as that of Hans
Koppe. At the same time he grasped Ross by the shoulder and literally
dragged him across the steel threshold. Vernon followed quickly, but
barely had he gained the compartment beyond than the massive steel door
shot back again.

"Didn't you hear the order all hands for'ard?" asked Hans, not
unkindly, for the white faces of the English lads told their own tale.

"No," replied Ross. "Besides, we are not included in the 'hands', are
we?"

"You'll have to bear the consequences if you don't obey," rejoined
Koppe. "I'm supposed to be looking after you, but how was I to know
you hadn't turned out? Fortunately for you, I heard your knocking, and
asked Herr Kapitan to open the doors. He was angry, but did so."

"What has happened then?" asked Trefusis, for the seaman seemed in