"He had been thirty years in slavery. How and where he had been captured he could no longer remember. His mind was a blank on that point. But one thing he told me that is important. For twenty years he had lived among the Gallas in a village fifty miles to the south of Harar, and it was a few years after he had been brought there that he nearly succeeded in making his escape.
"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.