s of activity on the part of the
submarine crew. Several men hurried along the alley-way, each with a
set purpose. They paid little heed to the Englanders as they passed.

At their heels came Herr Rix, the Leutnant of the submarine. He was
beaming affably.

"Goot mornings!" he exclaimed. "You come mit me, den I show you how we
blockade."

He led the way to the compartment in which the bowl of the
supplementary periscope was placed. It was now broad daylight, and
consequently the bowl showed a distinct image. A junior officer was
standing by, but on seeing Rix approach he saluted and moved aside.

"Look!" exclaimed the Leutnant.

Both lads peered into the bowl. On its dull sides, an expanse of sea
and sky was portrayed. Beyond that they could see nothing, until Rix
called their attention to a small dark object.

"Englische sheep!" he declared. "Now you vos watch."

He touched a metal stud. Instantly an arrangement of telescopic lenses
came into play within the tube of the periscope, with the result that a
small portion of the view was greatly magnified upon the object card.
It revealed a tramp of about nine hundred tons. She had a single
funnel painted black, with two broad red bands; two stumpy masts, with
derricks, and a lofty bridge and chart-house abaft the funnel. She was
wall-sided. Her rusty hull was originally painted black. Here and
there were squares of red lead, showing that her crew had been engaged
in trying to smarten her up before she reached port. Aft, frayed and
dirty with the smoke that poured from her funnel, floated the red
ensign.

The submarine began to rise. Although she tilted abruptly, the image
of the tramp steamer still remained upon the object bowl. By an
ingenious arrangement, the lenses were constructed to compensate for
any deviation of the tube of the periscope from the vertical. The lads
could see the bows of the U-boat shaking clear of the water, throwing
cascades of foam off on either side as the passing craft forged ahead
at at least eighteen knots.

Now, for the first time, the skipper of the tramp saw the danger. He
was a short, thick-set man, with white hair and an iron-grey moustache,
and a face the colour of mahogany. For an instant he grasped the
bridge-rails and looked towards the submarine, then gesticulated
violently to the man at the wheel.

The spikes ran through the helmsman's hands, as he rapidly revolved the
wheel actuating the steam steer