suspicion; but unless his study of the tenderfoot had been
wrong, Smithy would not be guilty of disobedience.

"Well, what am I thinking about?" was the way Thad took himself to task
presently; "trying to find the answer to a riddle by bothering my
brains, when it ought to be written here on the sand as plain as print."

Immediately he commenced to move about, looking for signs. Of course
there must be all manner of footprints there, some recent, and others
made on the occasion of the preceding visit of the scouts. But Thad had
studied trail finding more or less under the watchful eye of the Maine
boy, who knew considerable about it; and hence he was able to decide
what were new, and what old footprints.

And he had not been at this task more than half a minute when he
received considerable of a shock.

"Why, here's that footprint with the marked sole!" he whispered, a new
thrill in the region of his heart.

He could guess what that meant, for it was very fresh and new. The man
whom he now believed to be some sort of criminal, had been right there
on the beach since he, Thad, had quitted the spot to climb the tree
selected for his signaling operations!

And since Smithy was supposed to be waiting there, only one inference
could be drawn--the tenderfoot scout had fallen into the enemy's hands!

Evidently matters were approaching a crisis now. The two men who hid on
this island as though they feared their fellows to see them, were
beginning to grow bolder. At first they had only felt annoyed by the
coming of the scouts, and the making of the camp opposite their secret
retreat. Then, by degrees, as the boys began to infringe on their
territory, they had commenced to strike back; first by causing the boat
to disappear; and now by capturing poor Smithy, who must be nearly dead
with fright because of his peril.

Thad suspected the men may have begun to fear that their hiding-place
was known, and that the boys would be trying to either effect their
capture, or communicate their discovery to the authorities in some
neighboring town.

Perhaps they hoped to keep matters boiling at fever heat until night
fell, when they could make use of the recovered boat to slip away; or
else swim from the island retreat.

He looked further, and soon found marks that plainly told the story of a
struggle. It had been brief, however, for evidently Smithy was evidently
taken by surprise, and with his breath immediately cut off by a crue