topped. Gripping the rim of the
oval hatchway he gazed, horror-stricken, at two objects bobbing in the
water directly in the path of the submarine. Then, recovering his
voice, he shouted to the quartermaster to port helm.

The fellow obeyed promptly, but it was too late. Practically
simultaneously, two barrels swung round and crashed alongside the
submarine's hull.

Officers and men, expecting momentarily to find themselves blown into
the air, stood stock-still. Then, as nothing so disastrous occurred,
Schwalbe gave orders for easy astern.

The barrels, connected by a span of grass rope, had been thrown
overboard from the pursued vessel, in the hope that the submarine would
foul her propellers in the tangle of line. Once a blade picked up that
trailing rope, the latter would coil round the boss as tightly as a
band of flexible steel.

The plan all but succeeded; only the metal guards protecting the
propellers saved them from being hopelessly jammed. Yet the attempt
was attended with good results as far as the British ship was
concerned, for by the time U75 had lost way and had cautiously backed
away from the obstruction, the swift cargo-vessel had gained a distance
that put her beyond all chance of being overhauled.

Infuriated by his failure, Kapitan Schwalbe went aft and descended into
his cabin. He was hardly conscious of the presence of his two
involuntary guests as he passed. He was thinking of the fate that had
consigned him to a perilous and uncongenial task. Without doubt the
vessel he had been pursuing was equipped with wireless, and by this
time a number of those dreaded hornets would be tearing towards the
spot. To add to his discomfiture it was reported to him that the
reserve of fuel on board had seriously dwindled. In order to remain
effective it was necessary that U75 should replenish her tanks before
another forty-eight hours had passed.

According to his customary tactics, Schwalbe ordered the submarine to
dive to sixty feet. At that depth she would be safe from any
possibility of being rammed. Provided she could avoid the under-water
obstructions with which the British naval authorities had sown the bed
of the sea at almost every point likely to be frequented by lurking
hostile submarines, she was in no actual danger.

Gaining his diminutive cabin, Schwalbe by sheer force of habit
consulted the aneroid. The mercury was falling rapidly. Since he last
looked, barely two hours prev