As he approached, that spot widened promisingly; and when from time to time he caught glimpses of it through fissures in the rock, he became increasingly certain that it was indeed the doorway to a cavern. But what a cavern it must be! The opening was perhaps wide enough to admit half a dozen men walking side by side, and its coaly opaqueness brought visions of interminable depths. His imagination was not fully awakened, however, until he stood on a sort of rocky terrace or balcony directly facing the gaping hole. Then, when he saw the jagged aperture giving upon the tunnel-like recess, with the low roof that would barely admit his unstooping form, and the interior unillumined and blank as if here were the end of all things, a tremor of fear shot through him, and his horror-stricken mind conjured up all manner of fantastic terrors.

As if to lend some color of reason to his alarm, Wuff crouched down before him with bristling hair and eyes angrily shining; and from his throat there issued low growls and grumblings.

But Ru had no time for hesitation. His torch was already half burned away, and the cave must be explored while the flame lasted—and so, trying to forget his unreasoning dread, Ru forced his way into the blackness.

Reluctantly Wuff followed at his heels; but each second his growls grew louder.

Yet at first Ru was aware of nothing disturbing. There was only the bare floor and the shadowy walls dimly lit by the torch; and a new assurance came to him as he pressed farther into the gloom.

Then—not half a dozen seconds could have elapsed—he became conscious of a light that was not of his torch. From the darkness beyond, two phosphorescent eyes were staring out at him!

While he shuddered and thought of flight, and the mutterings of Wuff rose in a savage crescendo, the phosphorescent eyes lunged toward him, a sudden wind blew past, and a great body went bounding by. Ru screamed and waved his torch, and thereupon two more phosphorescent eyes emerged from the darkness; there came another puff of wind, and a second huge form went hurtling past. As it plunged into the rim of daylight and disappeared, Ru recognized the hideous spotted shape of a hyena.

For a moment he stood motionless, to make sure that no other beasts lurked in the shadows. Then, convinced that the routed pair had been the cave's sole tenants, he started slowly forward again; while Wuff, keeping close at his side, still growled a little and sniffed suspiciously at the cavern floor.

As he advanced, breathing the dank air that reeked with odors of dampness and decay, Ru observed that this cave was uncannily different from that which he had known. It twisted and turned confusingly; not for many yards anywhere did it keep a straight course; its roof was high in places, and in places so low that he could barely creep beneath; here and there huge stalactites, like gigantic tapering clubs, hung from the ceiling; and on the floor the pointed stalagmites bristled. And now and again he could hear the murmuring of invisible water—an eery murmuring, which sent queer little shudders down his spine and made him recall all the tales his people had ever told of evil spirits that dwelt in recesses of the mountains.

Yet, although he had a curious sense of things unearthly, Ru was fascinated. There was something enchanted about those great deserted shadowy vaults and galleries, illuminated only by the flickering of his torch; the silence, unbroken except by the sound of the unseen waters, acted upon him like a charm; and, as one in a magic spell, he wandered on and on, forgetful for the moment of the peril into which he was thrusting himself.