“Water!” sneeringly echoed a voice from the darkness behind them. “Say, rather, there is the secret of Guatavita!”
“Raoul Arthur!” exclaimed the others.
Letting go the handle of the windlass, they rushed to the spot where the Black Magnet had vanished. There, at one side of the rocky projection, stood Raoul, pale and haggard, the light in his lamp extinguished.
“I suspected this,” he said, as if his sudden reappearance among them were the most natural thing in the world. “I knew from the direction of the path that it led back to the lake. I have been trying to reach this place for years. Oh, yes! I had heard something about it before—I don’t deny that. But, of course, I expected to stay by you. So, when you started to leave the cave I came back, expecting to rejoin you. As I was examining the machine I was attacked by two men, thrown to the ground and left unconscious. I came to myself a few minutes ago—in time to congratulate you, it seems, upon solving the mystery of the cave.”
“That is strange,” said Leighton coldly. “You left us, without a word, at a time when you were needed. The attack that you say was made upon you we should have heard. But—we have heard nothing.”
“Believe me, or not, as you like; it is true,” was the sullen reply.
“Why do you say we have the secret of Guatavita?”
“Look!”
Raoul pointed to the projection in the wall behind which the Black Magnet had disappeared. It was not a shelf, as they had at first supposed, but the opening of a shaft, or well, that slanted downward at an angle that in the course of fifty feet, or less, would reach considerably beyond the vertical line of the cave’s wall. In shape this shaft was oblong, slightly larger in length and in breadth than the Black Magnet. It was evidently of artificial origin, its four walls being perfectly smooth and without irregularities of line. Even by one who had not seen the magnet descend into this shaft, its intended use as a sort of runway for raising and lowering heavy bodies would be quickly recognized. But where it led to was another matter. One thing was easily discovered: where it reached a point some twenty feet below the level of the cave’s floor the shaft was filled with water. Beyond this, of course, nothing could be made out. It was to the bottom of the pool thus indicated that the magnet had plunged.
“It is a well hewn out of the rock by Indians—or perhaps by Spaniards digging for gold,” said Leighton.