And as the sound broke upon his ears, both Max and Ibrahim groaned aloud. An oar had broken. “The paddle, quick!” Max seized the badly-shaped paddle, and tried to use it like an oar. In vain. The Arab’s oar was broken, and the boat and its occupants were at the mercy of the cruel river. Where was it taking them? Not to the whirlpool. That was passed long ago. They could see it again as they looked back. Ibrahim reached out his hand to seize a branch of a mimosa tree, but his effort was in vain. “See, what is that? Oh, Allah!” exclaimed the Persian as he saw the face of the dead Arab close to the boat, with its eyes open, and peering into the face of the young chief. “It is horrible!” groaned Max. On sped the boat, faster and yet faster. The living Arab was the picture of stoicism. He sat erect, his arms folded, the turban on his head scarcely wrinkled; but his teeth were clinched together, and he awaited death. Ibrahim had passed through the terror of the valley of the shadow of death, and had mentally wished his uncle farewell. As for Max, he was occupied thinking of a way to escape. And yet a few minutes of life only remained to them. The water had changed to dull, heavy red in color. All along the banks Max could see the quagmire the caravan had avoided. But the boat sped on so rapidly that nothing definite could be noted. It seemed the boat was going uphill, but of course that was imagination. A few yards before them was tall marsh grass growing in the water. “Our troubles are at an end,” gasped Max, catching his breath, as he spoke. The boat tossed slightly. A sudden lurch, and the small dugout, with its three occupants, was precipitated over a cataract, a seething cauldron of hissing, sputtering, bubbling water! CHAPTER XIV. THE SUBTERRANEAN RIVER. The sudden shooting of the cataract, the wild plunge into the water beneath, had taken away their breath, and neither Max nor Ibrahim was able to speak. Instinctively, the three men caught hold tightly of the sides of the dugout, and it was well that they did so, and maintained their grip like grim death. The boat rolled over and over, constantly righting itself, and its occupants got more baths in a few minutes than they cared for. They found the water quite warm, which was some consolation, for had it been icy cold they would have been unable to retain their hold upon the boat. How the water came tumbling down! All sorts of strange noises were made in its descent. To Max and Ibrahim it seemed that ten thousand peals of thunder had impressed themselves on the tympanum of their ears. The Arab might have been a statue of marble. He clutched the boat with both hands, but his features were as rigid as death. He had his eyes and mouth closed tightly, and had it not been for the swelling of his bosom he might have been thought dead.