man who covered Jack, and the German's bullet
went wild.

The commander of the submarine, at this juncture, losing his temper at
being pursued to the very door of safety, turned and sprang for Jack with
a wild cry. He was a big and powerful man, and as he wrapped his arms
about Jack, the lad staggered back.

But he recovered his balance in a moment and struck out with his right
fist. Struck in the stomach, the German grunted and stepped back.

Now the remainder of the German crew came pouring on deck. At the same
time Frank's launch grated alongside and his men poured a volley of rifle
bullets into the enemy. The latter turned and scampered for safety below
decks.

Jack, still struggling with the German commander, paused and looked around
long enough to cry:

"After them, Frank! Don't let them shut you out."

Frank understood and led his men toward the conning tower at a run. Most
of the enemy were already inside and descending, but Frank arrived in time
to prevent the closing of the conning tower, which would have permitted
the submarine to submerge, leaving the struggling figures in the water.
With the conning tower open, it was, of course, impossible for the U-Boat
to submerge, for she would have been flooded immediately.

Frank's men made prisoners of the half a dozen Germans who had not time to
get below, and then the lad ran over to help Jack.

"Keep away, Frank," said Jack. "I've got this fellow, and I hope he
doesn't give up too easily. We've heavy accounts to settle with him."

The big German showed no symptoms of giving up. He lashed out with both
arms and Jack was kept busy warding off the blows. But the German
commander was a novice at this sort of fighting, while Jack, only a year
or so before, had won the heavyweight boxing championship of the British
navy. So there was no doubt in Frank's mind as to the outcome. He and his
men formed a circle around the struggling figures, at the same time
guarding the conning tower to prevent the enemy from closing it.

"Shoot the first head you see down there," Frank enjoined the men he left
on guard, and he knew they would be only too glad to obey this order.

Jack, with a smile still on his face, permitted the German commander to
waste his energy in ineffective blows. Then Jack stepped forward and
delivered a heavy blow to the man's mouth. The German staggered back. Jack
doubled him up with a left-handed punch to the pit of the stomach, then
straightened h