nd shook the water out of his long black hair. Then he
turned for a glance around him. In front of him loomed the sand
dunes, their weird shifting formations dotted here and there with
scraggly underbrush. Down the coast the picture was the same.

Turning, the lad gazed northward in the general direction where he
knew lay Holland and her neutral shores.

"That's where I go from here," he said cheerfully.

He had jogged along not more than a quarter of a mile when the coast
line veered sharply to right, leaving only the expanse of ocean
looming up beyond the stretch of sandy beach. Following along the
curve in the coast line, Jack found himself presently on the shore
of a small land-locked bay. The mouth of the inlet was barely wide
enough to permit the passage of a good-sized vessel.

But neither ship nor human being was in sight.

"Might be one of the secret passageways used by the undersea boats,"
Jack mused as he followed the curving line of the bay away from the
ocean.

Presently he came to an abrupt halt at a break in the beach where
the rolling sand dunes fell sheer away to the mouth of another
waterway---this time a small stream that wound its way inland through
a tortuous channel. It was no more than two hundred feet across.

Jack realized this must be one of the canals with which the coast
was known to be ribboned. For a moment he stood in contemplation
of the sight. Now he was more than ever convinced that he had
stumbled into a U-boat base. The love of adventure gripped him and
he determined to press on.

For the next ten minutes he threaded his way along the canal bank.
Suddenly, as he turned one of the snake-like twists in the course of
the waterway, he found himself facing an old stone windmill that stood
almost directly on the canal bank. It was only a stone's throw away.

Instinctively the boy threw himself upon the sandy loam. There was
not a sign of life about the abandoned structure. In the peaceful
days before the war it had, no doubt, been used by a Belgian farmer
to water his fields.

But now Jack saw something that set his heart a-flutter. From the
dome-like crest of the windmill stretched a number of wires tautly
drawn and leading away to some point beyond his range of view. For
a moment he contemplated the scene in silence with tingling nerves.
Satisfied at last that his presence was not yet known---if any human
being was within the stone tower---he struggled up to a kn