"I believe I know where it was," Hugh told him simply. "You see, I noted several things about the face of the quarry that day we stopped to look it over; and when I saw that dancing trail of fire I figured out that it must be at just such a place, which spot I'm heading for right now. And just as you spoke I had ample proof that I was right in my guess."

"Why, what happened, Hugh?" demanded Horatio eagerly.

"I caught a faint glimpse of light up there," Hugh told him. "I wonder none of the rest of you happened to notice the same. It made me think that some person might be in one of those holes we saw in the face of the wall—-caves, the natives call them, Horatio says. As this was somewhat deep only a tiny bit of illumination escaped, and you could just detect that when at a certain angle. Stop short, now, and see for yourselves, for there it is again!"

Thrilled to the bone they stood and gaped. Hugh was pointing with his disengaged hand, half holding the lantern back of him so that its glow might not further interfere with their view.

"You're right, Hugh; that's surely what it is," greed Thad, almost immediately; and each of the other three went on record with a corresponding affirmative.

"Then the next thing for us to do is to find some way of climbing up to that same fissure," the leader explained, showing that he meant to lose no time in trying to open negotiations with the unknown denizens of the quarry, whose actions were becoming more and more mysterious as time passed.

"Which means that we're going to beard the tiger in his den," quoth Owen, gripping his gun more firmly as he edged a little closer to Hugh; for since he was the only member of the expedition who could be said to possess a weapon it was proper that he should be found in the van at such a crisis.

They walked on, not hastily, and showing no outward sign of the tumult that must have raged in each boyish heart. Now it was no longer possible for them to discern that faint glow; but such a little thing did not daunt them. Hugh had marked well the exact location of their objective point, and Hugh seldom made mistakes, those other confident fellows were telling themselves as they cheerfully trudged along.

The foot of the cliff was at hand. Rains and winds and snow avalanches had, during the years that had passed since the hands of men worked those diggings, served to cut loose great quantities of debris from the face of the height, so that here and there at the foot irregular pyramids of earth and rocks could be seen. Hugh now seemed to have turned his attention from above and was bending half over, as though examining the ground. Owen knew what this meant. The other anticipated finding a track leading directly to the route by means of which that cavern halfway up the cliff might be easiest attained.

And, as often happens, such reasoning proved to be the wisest thing the searchers could have undertaken, for hardly had half a minute elapsed an Hugh was heard to give vent to a low ejaculation of gratification.