't turn here."

The boat passed under the great bridge and on through the seething
rapids. It ran on for a little distance, then circled and swung back.
Again it passed through the angry waters, then made a wide circuit,
steaming slowly along the land, while those aboard searched the
darkness, peering into every curve and indentation of the shore, to try
to spy out some sign of life. Tugs were shunting car barges, and an
occasional steam craft passed, but nowhere was there a sign of a
motor-boat or of the fugitive Germans.

A great doubt came into Captain Hardy's mind. Could it be that after
all they had been on a wild-goose chase? He had thought the connection
between Hell Gate and the Balaklavan rendezvous far-fetched. But it
had been the one chance left. They had tried the theory out and they
were wrong. The wireless patrol had not merely lost the Germans. They
had lost all trace of them. They had failed in the crisis.

CHAPTER XX

A CLUE FROM THE AIR

Slowly the little police-boat finished her circuit, nosing into every
dark nook and spying out every black corner; but blacker than either
the night or the water was the gloom in the hearts of Captain Hardy and
his fellow members of the wireless patrol. With bowed head the
disappointed leader turned to the commander of the boat, to tell him to
return to his dock. But Captain Hardy was too loyal to his fellows,
too resentful of Lieutenant Gavigan's remarks about them to indicate by
word or act that he thought they had been on a wild-goose chase. So he
said simply, "We were too late, Lieutenant. They have given us the
slip. But none the less I thank you for your assistance."

Then he turned aside and stood peering gloomily into the dark waters,
that reflected the exact shade of his own mind. Appreciating better
than his youthful companions the full extent of the disaster that had
befallen them, he could not, for the time being, summon up his usual
fortitude or see any hopeful prospect. Now that the spies knew that
they were discovered, he felt sure that they would never risk the
sending of another wireless message. And a wireless message was the
sole clue by which his little patrol might once more pick up the trail
of the fugitives.

But Captain Hardy's disappointment was no whit keener than that of his
fellows, nor his sufferings any more poignant; yet with the buoyancy of
inexperienced youth, hope was not entirely crushed in the heart of