n the center of this upland, cliff-guarded
valley, a gaping black orifice which every faculty of judgment told him
was the mouth of the geyser of perfume. And beside it, outstretched on a
smooth sheet of rock which glistened as though coated with a layer of
clear, sparkling glass, he saw--

* * * * *

Kirby blinked his eyes rapidly, hardly believing what he saw.

On the glistening rock lay the perfectly preserved figure of a Spanish
Conquistadore in full armor. Morion and breast-plate were in place, and
glistened as though they had been burnished this morning. And the
Spaniard's dark, handsome, bearded face! Kirby saw instantly that no
decay had touched it, that even the hairs of the beard were perfect. The
whole armor-clad corpse gleamed softly with a covering of the same
glassy substance which covered the rock.

Kirby glanced at his watch, saw that twelve minutes must elapse before
the geyser spouted again. Then his eyes narrowed. He remained standing
where he was, hard by the mouth of the tunnel, knowing that a wise man
would conduct cautiously his exploration of this valley of wonders.

Arsenic! Silicon!

The two words stood out sharply in his thought. In Africa existed plenty
of springs whose waters contained enough arsenic to bring death to those
who drank. Might not the Spaniard's presence here be explained, then, by
assuming that the geyser water was charged with a strong arsenic
content, and, in addition, with some sort of silicon solution which,
left to dry in the air, hardened to glass?

Lord, what a discovery to take back with him to Kansas! Almost it made
the discovery of the golden cylinder pale by comparison. Why, the
commercial uses to which this silicon water might be put were almost
without limit, and the owner of the concession might confidently expect
to make millions!

It was while Kirby stood there, breathless and jubilant, waiting for
the geyser to spout, that he began to feel that _he was being watched_.

Suddenly, with a start, he shot a sweeping glance over the whole grove.
But that did no good. He saw nothing save sunlight and waving green
leaves.

Eleven days were to pass before he discovered all that was to be
involved in that sensation of being gazed at by unseen eyes.

CHAPTER III

At the beginning of the eleventh morning in the valley, Kirby had again
posted himself close to the mouth of the black tunnel, and again felt
that hidden eyes were