s on the wharf."

"And did I pass muster?" I queried.

"Sure you did!" he cried enthusiastically. "Miss Barbara Herndon says
that you are true blue, and Miss Edith--"

He stopped and looked at a patch of shadow near the galley. "Some one is
hiding there," he whispered. "I saw him sneak into it."

"Nonsense!" I growled. "The moon and something else are affecting your
brain."

"But I'm sure of it," he gasped.

He sprang for the spot as he finished speaking, but he found nothing. He
returned to my side shaking his head as if only half convinced about the
matter.

"Some one was listening to us talking, but whoever it was he managed to
slip away while we were arguing the question."

"Well, he didn't learn much," I said. "It was probably one of the
islanders, and you've scared the life out of him now."

Holman gripped my arm as I turned away, and he put a question in a tense
whisper.

"What do you think of Leith?" he asked.

Somehow the question did not surprise me, but I was not in a hurry to
give my opinion of the, Professor's partner.

"I have only spoken a few words to him," I countered cautiously.

"But your impression?" stammered the youngster. "Don't you think--well,
of course you haven't got the lay of things yet."

I smiled at the guilelessness of the boy who was making a confidant of
a stranger. "What's wrong with Leith?" I asked. "What are you hinting
at?"

Holman glanced at the Tongan at the wheel, then at the shadow patch that
had disturbed his nerves a few moments before.

"He's the devil!" he whispered.

I felt inclined to laugh. Leith was certainly not a person that one
would take to the moment an introduction was given, but the manner in
which the young fellow had imparted his opinion was amusing. But it was
evident that I had not guessed wrong when I divined trouble the moment I
came over the side of the yacht.

Holman caught my coat with his left hand as we turned, and he spoke
excitedly.

"Do you know what we're after?" he queried hoarsely.

"It's a scientific expedition," I replied. "That's what you and Captain
Newmarch told me, and I have not questioned any one else."

"But do you know the particular line we are after?"

"No," I replied.

"Well, we're after skulls. Leith has told the Professor about some
ancient boneyard that he knows of, and he's dragging old Herndon down
there."

"I cannot see the crime now," I said. "I've gone after skulls before
to-day. I brought a hu