Every time the boat was submerged it was carried further away from the cataract, and in a very few minutes--but the few minutes seemed an eternity--the water grew calmer and the boat more steady. Then it was that they opened their eyes. “Am I blind?” asked Ibrahim. “Am I?” echoed Max. The Arab was asked if he could see anything, and he answered in the negative. “Then we are blind!” Max solemnly asserted. “Why so?” “We cannot see.” “True.” “Is not that sufficient evidence?” “No.” “Why not?” “Because we may be underground.” “You mean----?” “That we are on the breast of a subterranean river, flowing under the desert.” “You mean it?” “Is it not as probable as that we are all blind?” “Perhaps so.” The water was as calm as a stagnant pool. Scarcely a ripple passed over its surface. And yet the boat was borne along quietly and slowly. Max had recovered his good spirits, and with them his appetite. “I am hungry.” “So am I.” “Let us refresh.” Fortunately the packages of food were all incased in waterproof covering, a precaution which should always be taken by explorers. One of the packages was unfastened from the Arab’s back, and a thoroughly good repast was partaken by all three. “I feel ever so much braver,” said Ibrahim. “Yes, there is a great satisfaction in having a full stomach.” “How do you feel, Selim?” The man groaned, wearily, and in a quaint manner told his master that he felt bad. “I shall die,” he said, “and I don’t want to do so. Before I ate salt with your excellency I wanted to die, but now--I don’t like it at all.” The Arab had been so miserable that all terror had been removed from the thought of death. His appetite satisfied, his love of life grew stronger, and the very thought of his impending fate was horrible. “Hold my hand,” suddenly exclaimed Max. “What are you going to do?” “Never mind; I want to stand up, and this confounded boat is so shaky I am afraid I’ll fall over into the water.” Ibrahim grasped Max around the legs, while Selim held one hand. Max raised the other above his head. He was trying if he could touch anything which would satisfy him that they were really drifting through a tunnel. But he could not reach anything. If he really were in a subterranean cave or passage, the roof was too lofty for him to reach. On went the boat, its speed gradually increasing. Its occupants were victims of fate. They were without paddle or oar, and had positively no means of guiding or directing the boat. Ibrahim put his hand into the water, and exclaimed: “It is hot!” Max repeated the experiment, and found that the water was many degrees warmer than it had been. “What do you make of it?” Max asked. “That the air being more confined causes the water to be warmer.” “Absurd! It would be the exact opposite of that. The water ought to be colder.” “What is your theory?” “We are approaching a boiling spring.” “That is a pleasant reflection--see, can you discern anything?”