some danger."

"But we might as well have some sport along with it," argued Andy, who
could not help seeing the funny or bright side of everything. Frank,
though more serious, did not despise a good time by any means, but he
went at matters more determinedly than did his brother.

"To my notion, the first thing to do is to go at this search with a
system," went on the older lad. "We'll climb up to the top of the
cliff, and see if we can make out anything from there. If that man is
here he may have set up a camp, and built a fire. If he has, we can
easily see it from the cliff. Then we will know where we're at."

To this Andy agreed, and soon they were toiling to the top of the high
land that ran lengthwise of the island, roughly dividing it into two
parts. It was no easy matter to reach the summit, and several times
the boys had to stop for a rest. But finally they were at the goal.

Below them, on all sides, washing the rocky shores of the island were
the heaving waters of the great bay. They could take in most of the
shore line, irregular and indented as it was, but, look as they did,
there was no sign of life.

They saw no curling smoke from a campfire. They saw no figure of a
man--the man whom they had so fruitlessly pursued. Nor was there any
vestige of a big motor boat half-burned.

"Well, nothing doing so far," remarked Frank, after a pause. "Now
we'll go down and begin a circuit of the shore and see what is in some
of the caves."

Slipping and sliding over the loose stones and gravel, they reached the
bottom of the slope near where they had drawn up their boat. The sight
of this craft gave Frank an idea.

"Suppose while we're on one side of the island that man--or
someone--should happen to come along?" he suggested. "He'd make off
with our boat, sure."

"Probably," agreed Andy. "But we can prevent that."

"How?"

"By hiding the oars. We'll shove 'em under some bushes quite a
distance back, so they can't be found."

Frank agreed that this was a good idea, and though there was a chance
that someone might land in a motor boat and tow off their rowing craft,
still they had to take that risk.

Then began a systematic search of the island. They went along the
shore, and looked into many small caves. The interior of these was
dark, but they had each provided a pocket portable electric flash lamp,
so that they were able to illuminate the caverns.

"Nothing here," announced Frank, afte