“Do you know what that is?” he demanded.
No one did. Miranda shrugged his shoulders and turned his attention ostentatiously elsewhere, as if floating balls of crackling white flames, used to illuminate caves, were matters of ordinary experience with him. Andrew’s mouth was opened quite as wide as his eyes as he stood staring upward at the curious illumination. It would be a splendid saving of candle power, he thought, more than enough for the whole village, if they could only manage to take it back with them to Rysdale. But, even if it were small enough, it wouldn’t be possible to carry in one of their trunks, since it would be sure to set things on fire. This objection was made by Mrs. Quayle, and seemed reasonable enough.
“That is the most remarkable thing on earth,” went on Leighton, heedless, in his excitement, of the frivolous comments of his companions. “I have often thought that sooner or later something like this would be discovered. It is impossible to estimate its value. Why, all the billions of dollars that there are in the world to-day could not pay for it at the present market prices.”
The calm assurance with which this estimate was given shattered Miranda’s pose of studied indifference.
“What is it?” he asked sharply.
“Radium!”
The silence that followed was eloquent of the mingled incredulity and delight with which so staggering an announcement was received. Leighton, fascinated with his subject, proceeded to explain things, much as if he were at home again in his laboratory, working out a particularly novel experiment, and expounding his various theories of physics. Of course, he had nothing but theory to go on, since he had never seen, heard of, or believed possible such a huge mass of radium as this that hung above them. And because it was so unbelievably huge, the others refused at first to take it for what he said it was. But he insisted that it could be nothing else. Radium it was—and with this as his basis of fact, he quickly built up an imposing theory that he used to explain more than one matter that before had puzzled them.
This immense globe of radium, he believed, in the first place, was the parent-body of all the infinitesimal particles of this remarkable substance that had recently been found in different parts of the world. The mysterious properties of radium, he said, were only dimly understood as yet by physicists who had experimented with it. Apparently it was a mineral; but as it revealed a constant and amazing activity, throwing out a force that so far had baffled analysis, there were those who held that it was a living, or, better yet, a life-giving substance. The existence of this immense body of radium here, in the center of the cave, explained, to the satisfaction of Leighton, much of the strange phenomena they had seen. Here, obviously, was the source of the soft, diffused light that had puzzled them ever since they passed through the Condor Gate; and it was to this center of energy that they must attribute the increase in buoyancy and physical well-being experienced the further they penetrated into this subterranean world. The peculiar growths, also, half vegetable, half mineral, that had given the appearance of groves and gardens to certain portions of the cave through which they traveled, were undoubtedly due to this marvelous force, occupying the same relative position towards subterranean life that the sun did to the outside world of nature. Moreover, Leighton firmly believed that the supremacy of radium as the life-giver in this cave, involved the existence, as they would discover, of other phenomena having still more subtle, even psychic, qualities. Narva grunted significantly at this observation, and Una confirmed the truth of it by relating how the floor of the court where they were standing had, only a short time before, reflected a series of pictures of events taking place in the outside cave, by means of which they had been able to follow Leighton’s approach to the palace and watched the collision of his party with that of Raoul. It was through this peculiar photographic power of radium, indeed, that Sajipona could discover whatever was taking place in the remotest regions of her domain. This information did not surprise Leighton in the least. On the contrary, he appeared to take it as a matter of course, one of many marvels that might be expected in a land run, so to speak, by radium.
Absorbed in the discussion of these matters, no one noticed the entrance of Sajipona. The queen, coming from the apartment where she had left David and Raoul, was not in a hurry to make her presence known, and lingered long enough behind the others to enjoy the curiosity and wonder with which they were regarding the globe of light above them. She now advanced smilingly, addressing herself particularly to Leighton, whom she complimented for his shrewd guess as to the nature of the force pervading and governing the cave. Indian though she was, inheritor of a realm that, in all its customs and beliefs, was primitive, distant from the civilizations found elsewhere in the world to-day, she had heard and studied enough of Europe and America to be familiar with some of the momentous discoveries of modern science. Hence, she had been quick to grasp the fact that this subterranean sun, worshiped by her ancestors ages ago as the Life Giver—the God that, according to Indian legend, resided under Lake Guatavita—was nothing more nor less than an immense body of radium, the most precious substance known to man, the scarcity of which had led scientists to ransack the uttermost parts of the earth in the hope of adding to their store of it. Here it had always been, the one priceless possession of her people, enabling them to live apart, independent of the world that threatened at one time to exterminate them. How this radium had come there originally she could not tell. It was the result, doubtless, of hidden forces about which philosopher and scientist are as yet ignorant. Or, it might itself be the architect of the subterranean world whose extent and manifold marvels had amazed the explorers. By means of this radium force, as Una had told them, she was able to see what was happening in any part of the cave, even throughout that dark region lying beyond the Condor Gate—an incredible statement, as it appeared to Leighton. For they had been in this outer cave and discovered in it neither the light nor the warmth they had enjoyed on this side the Condor Gate. Hence, argued the savant, this outer cave appeared to lie entirely beyond the zone of radium influence. Sajipona smiled at Leighton’s objection and asked him if nothing had occurred in the outer cave, while he was there, that he had been unable to explain. They had been through so many marvels in so short a time that the explorers looked at each other doubtfully. Mrs. Quayle answered for them.
“Yes, the terrible stone that pulled off my jewelry, and then dragged gold up from the lake outside—how was that done?” she asked, still smarting, apparently, from the indignities she had suffered.