"He had often heard from the natives of an underground river that was said to exist, and which emptied either into the River Juba or into the sea. The tales concerning the river were many and strange, but the chief of the Gallas assured him that at one time a tribe of natives had lived in the mouth of a huge cavern which gave access to the river." "I have heard something of that myself," interrupted Melton. "An Arab at Zanzibar told me, but I never had any faith in the story." "That river exists," said Canaris solemnly. "The Englishman found it." "What!" cried Guy and Melton in one breath. "He found the underground river?" "Yes, he discovered it," resumed Canaris. "He found it one day while hunting in a concealed cavern. He ventured down and came to a great sandy beach, past which flowed swiftly a broad stream. On the beach lay half a dozen strong canoes with paddles. All this he saw by the light that streamed in from narrow crevices overhead. He went back to the village and began to lay aside provisions for the journey, for he intended making his escape by the river. In a week all was ready. He had concealed near the cavern supplies for a long voyage. The very day fixed for his escape he was sold to a Galla chief who lived twenty miles distant. In the years that followed he made many attempts to escape, but on every occasion was captured and brought back. At last he was given as tribute to the Emir by this Galla chief, and here in this dungeon, on the spot you are sitting on now, he breathed his last." Canaris paused and helped himself to a glass of water. "A strange story, indeed," said Guy; "but what has it got to do with us?" "I will tell you," responded Canaris, with a slight tremor in his voice. "It may have nothing to do with any of us, and it may be of the greatest importance to us all." "Did the old man tell you where to find the cavern?" asked Guy. "No," answered Canaris, "but before he died he gave me this," and, pulling a folded bit of linen from his pocket he handed it to Guy. "Can you read that?" he asked in strange excitement. "I have never been able to make anything out of it." Guy pulled it carefully open and gazed with interest on the faded characters that had apparently been written in blood. "Yes," he said after a pause, "I can read it. It is French." "Go on," said Canaris. "Tell me quickly what it is." "It translates as follows," rejoined Guy: "Half way between Elephant Peak and the Lion's Head. The south side of the stone kraal. The rock with the cross." Canaris sprang to his feet and staggered back against the wall of the dungeon. "It was Providence that brought you here," he cried. "It is wonderful, wonderful!" "What do you mean?" said Guy. "How can this aid us?" "It is the secret of the cave," replied Canaris. "The stone kraal is a curious formation of rocks that lie between the two mountains that bear those names. Close by is the village of the chief of all the Gallas."