The boy decided to act with caution. With such an opponent as the sheikh he knew he would be called upon to exercise not only promptitude but cunning. It had not been without difficulty that he had managed to persuade the guides to allow him to enter the temple. Fernando, who was filled with a strong desire for vengeance, had wished for the honour for himself. But Harry, as the leader of the expedition, would not give way, agreeing that the moment he fired the elder guide should hasten to his assistance.
Ready to fire at a moment's notice, Harry set about a systematic search of the ruined temple. Starting from the entrance, he worked his way around the walls, holding as much as possible to the shadows. He looked behind each boulder, he searched each crevice that appeared large enough to admit the body of a man. In the end he returned to the entrance. The place was evidently deserted.
His first thought was to leave the building, to tell Cortes that he had been mistaken, that the sheikh was not there; but then he remembered how seldom the judgment of either of the guides had been at fault, and, assuring himself that he had overlooked some hiding-place, he began his search anew.
He came to a place where a clump of cactus was growing against the wall, and here he discovered what he had not noticed before. Under the cactus plant was a little archway, a kind of tunnel, large enough to admit a man crawling on hands and knees.
The boy was in two minds what to do. It was one thing to search from boulder to boulder, ready to fire at a moment's notice; it was another to go head foremost on all-fours into what might prove to be a trap. If the Arab was hiding on the other side of the wall, beyond the cactus-bush—a stroke of the knife, and the matter would be ended. The boy had need of all the courage he possessed. To go back to Jim and the two guides would be to confess himself afraid.
Taking a deep breath, like a man about to dive, he lay flat upon his face, and as silently as possible worked his way forward through the sand, which was still warm from the rays of the sun of the preceding day.
If there were many holes in the wall such as this, it was well three of them had remained on guard without. Had all four entered the temple at once, the sheikh, if he lay anywhere in hiding, had a sure way of escape. Harry had no means of knowing whether the hole led to the desert or to an inner room.
On the other side of the wall it was quite dark. The boy looked overhead, and was able to see that he was sheltered by a roof—a roof in which there were great holes, through which he could see the stars. He could do nothing as yet, until his eyes had grown accustomed to the darkness.
For some moments he lay still, his heart thumping against his ribs, straining his ears to catch the slightest sound. From somewhere quite near at hand, at first almost imperceptible but gradually growing louder, came a low, soft, vibrating noise that seemed to proceed from somewhere under the ground.
Harry thought he had heard something like it before; he could not remember where. It was like the droning of a monster bee, or the noise of a kettle on the point of boiling over, or else the purring of a cat.