s. What did this man know about Walter? Possibly,
through him the great mystery, that commenced with the note in the seat
of their boat, would be explained.

After they came back to the island, Retlaw rapidly recovered, and was
frequently found wandering around the town. On several occasions he
called on the Professor. To the surprise of all he appeared at this
time, surprised to find John and the boys present, and appeared to be
terribly startled on seeing the two skulls.

The moment he saw the paralytic, he became agitated, and started for the
door. John barred the way, and said: "Do you know that man?"

In a hesitating voice, he answered: "Yes; I know him well. Where did you
find him?" and notwithstanding he saw the quiet figure he drew back with
an expression of fear and hesitancy.

George slyly drew forth the Walter note, referred to in the previous
volume, "Adventures on Strange Islands," and handed it to John. The
latter seized it and said: "Did you ever see this?"

He grasped the paper, and answered: "Where did you get this? Did he have
it?"

"No," replied the Professor; "we found it in a recess at the end of a
seat in our boat,--the one we made on this island, three years ago."

"I do not know how it could have gotten there. It was written to
Clifford,--"

"John B. Clifford?" asked Harry in excitement.

Retlaw turned, when he heard Harry. "Yes," was the hesitating answer.

"Do you know Walter?" asked John.

He did not reply, but glanced at all of them, and while doing so Harry
came forward, and said: "Isn't your name Walter?"

The man started back and held up his hand: "What makes you think so?" he
asked in alarm.

"Because _Retlaw_ reversed, spells Walter," answered Harry.

It was time for the Professor to show surprise at the acuteness of
Harry's conclusions. John took the cue at once. "Why are you trying to
deceive us?"

He dropped his eyes, and was silent, and then he slowly turned to the
quiet man.

John noticed the movement. "Who was the man tied to the vessel and
wrecked on the island to the south of us?"

This question by John produced an added agitation in the deportment of
the man. He was visibly affected by the question, but there was no
reply.

"As you do not feel disposed to answer our questions we must detain or
keep you in custody until Clifford recovers," said John, and motioning
to the boys, they gathered around him, and called in the attendants and
ordered the men to ta