r an inspection of the first one.
And that was the result in all the others that they penetrated before
dusk. By nightfall they had covered perhaps a quarter of the shore
line and then they turned back.

A roaring blaze was kindled on the sand from the plentiful supply of
driftwood that strewed the beach, and at the cheerful fire they sat and
talked as they ate their supper.

"Jolly fun, isn't it?" asked Andy.

"It sure is, even if we don't discover anything. I wish Paul was
along."

"Perhaps it's just as well he's home," commented the younger lad. "I
have an idea that this man keeps informed of our movements, and don't
fancy having him sneak up on us during the night, which he would be
very likely to do if Paul was with us."

"That's so. But, speaking of night, what are we going to do about
sleeping?"

"Under our boat, with our blankets spread out on the sands," said the
younger lad. "It's plenty warm enough."

It was not a half bad way to spend the night, especially as the
overturned rowboat kept off the chilly dew. Soon the two brothers were
soundly sleeping. They did not bother to keep a watch and even allowed
the fire to die out, taking the precaution, however, to put some wood
under the boat, where it would be dry in case of rain in the night.

"Well, now for another try at the mysterious man!" called Frank, as he
crawled out from under their shelter the next morning. "Maybe we'll
have better luck to-day."

They set off directly after breakfast, and took with them their
blankets and a supply of food. For they intended to make a half
circuit of the island that day, and they figured that night would find
them too far away from their camp to make it practical to return.

"We'll eat and sleep wherever we are when it's dark," decided Frank.

Their search that day was as fruitless as fore. Not a vestige of the
man or boat to be seen. They made a sort of shelter of driftwood and
seaweed before darkness fell, and built a rousing fire in front of it,
where they sat and talked until it was time to turn in.

"I don't like the looks of the weather," remarked Frank as he wrapped
up in his blankets.

"Why not?" his brother wanted to know.

"It looks like rain, and if it does we're going get wet."

"Oh, I guess not," said the younger lad easily. He never looked for
trouble.

It was along toward morning when Frank awoke from a troubled dream that
he was standing under a shower bath. He found it t