position he had a clear view of the top of the big table, and
as I reached him I looked through an opening in the thick leaves. The
top of the stone was empty!

"Do you think he slipped down while I was climbing the tree?" asked
Holman.

"I'm certain he didn't," I answered. "It would have been impossible."

We stared at the stone in silence. The top was covered with short moss
that had gathered there through the centuries, and instead of being flat
as we had surmised there was a noticeable slope, so that the part that
was directly behind the camp was fully two feet higher than the rear.
This was the only peculiarity in its construction, and although we sat
in silence, staring at its moss-covered surface, we were utterly unable
to put forward the slightest supposition that would account for the
disappearance of the watcher. The incident was an extraordinary one. The
man could not have dropped from the table before we reached the
supporting piers, and we were equally certain that he had not slipped
down the pillars while we stood guard beneath.

"I'm going up there," muttered Holman. "We can get the rope from the
camp. Come along! I'd like a look at that place at closer quarters."

We climbed hastily down the tree, crept cautiously back to the camp and
took the stout rope which we had used in reaching the Ledge of Death.
The camp was quiet. The curious nasal sounds produced by the natives,
together with the rather high-toned snore of Professor Herndon, were the
only sounds that came through the still night.

Holman flung one end of the rope over a projecting corner of the flat
slab, twisted one half of it round and round the pillar to make
occasional grips which we could use in the ascent, then clutching the
hanging end he worked himself slowly up. I followed him, only to find
the upper surface of the table as bare of any signs of life as we had
previously noted from our perch in the chestnut tree. The tough moss
upon the stone was fully four inches long, and covered the slab
completely. In vain we stamped around looking for a possible hiding
place. The massive block didn't offer a cranny that a lizard could hide
in, and with an unsolved mystery upon our hands we descended to the
ground.

"What do you make of it?" asked Holman.

I shook my head. The enigma baffled me. Our suspicions regarding the
honesty of Leith made the strange appearance of the figure on the table
of stone more perplexing than it would have be