* * * * * 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 observing him. But this morning differed from the first morning, because now, for the first time, he was ready to do something about the watcher or watchers. Exploration of the whole valley had not helped. Therefore, there lay at his feet a considerable coil of rope, the manufacture of which from plaited strands of the tough grass in his Eden had taken him whole days. With what patience he could find, he was waiting for the gigantic spout of milky-colored, perfumed water which would mean that the geyser had gone off and would erupt no more for exactly forty-four minutes. Eleven days in the valley!