Royce now saw beneath him half a dozen steep steps leading down into gloom. He descended carefully, lighting his way with the candle, and found himself in a passage, narrower than the upper one, but much cooler and less stuffy. From the direction of the cave there was a steady draught.
Moving against it, Royce, after about fifty paces, caught sight of a glint of light ahead. He pressed on eagerly, and discovered that the passage ended in an opening roughly circular in shape, about a yard in diameter. Passing on, he came out into a tangle of brushwood through which he saw trees. He forced his way forward, and stood in a clump of woodland. There was nobody to be seen, no sound. He stole cautiously among the trees until he came to the edge of the clump. It looked over open country. Glancing round, taking care to keep hidden from observation, he saw at last the fort, on the hill about two hundred yards away.
"This must be the clump we noticed," he thought. "Now I understand why Goruba has not used it for cover in attacking us. He doesn't want any of his men to discover the secret entrance to his hoard. Of course, with the slab down they couldn't find the hoard itself, but evidently he doesn't mean to be bothered with inconvenient questions. Well, Mr. Goruba, I have caught you out. I only wish I could catch you."
Royce made his way back quickly, feeling that he was perhaps risking a good deal in leaving the men so long. He carefully replaced the two slabs, ascended the wall of the well, much to Kulana's relief, and, having assured himself that the garrison were at their posts and that the enemy had made no move, he sat down to devise a trap for Goruba.
"I suppose the fellow will come again," he thought. "Why does he come at all? A visit to the cave and no farther would prove that his treasure is safe. I suppose his idea in penetrating right into the fort is to spy, perhaps to frighten the men into deserting me. I mean to stop your little game, my man."
His first notion was to place a couple of sentries in the cave, to catch Goruba on his next appearance. In the darkness the giant would not see them. But he soon gave that up. It would probably be better not to let the men know anything about the cave for the present. Besides, he could not tell when Goruba would pay his next visit, and the superstitious negroes would never endure a long wait in the dark.
After long puzzling, Royce hit on a plan that seemed likely to be successful. He attached a thin cord to the slab in the well, at a point where it would not be seen in the semi-darkness by any one entering from the passage.
Carrying the cord round the well, he passed it through hooks of his own devising—nails driven into the brickwork and bent almost double. At the top he fastened similar hooks to the wall of the well-yard, near the floor, drew the cord through them, and finally tied it to the topmost of a short column of empty meat tins in his own room.
When this was done, he went down to the well again, turned the slab gently on its axis, and in a moment or two heard a slight clatter as the tins were overturned.
"I call that a stroke of genius," he said to himself. "The question is, will the sound scare Goruba away? He is bound to hear it, though it is not so loud as I expected. But, after all, there is nothing to make him connect the sound with his own movements, so I fancy there will be a little surprise in store for him."