"As my daughter knows," began Santiago in a feeble voice, "I am a direct descendant of the great Montezuma. My ancestor was the guardian of the treasure which had been accumulated by the Aztec kings for years. After the overthrow of my race by the Spanish conquerors, there was given to my first great ancestor the keeping of the secret of the source of the gold which had made the city of Anahuac such a rich prize. "This secret has been handed down through all these generations, the one object being to use this knowledge in freeing Mexico from the Spanish yoke. This secret I, as the last of my race, possess." The aged man paused, his strength being hardly able to the task he had set himself. "It is much as I suspected," whispered Don Esteban to Donald, while Lucia bent over and smoothed the brow of the sick man. "A few years ago," Santiago finally continued, "I began to see an opportunity for the people to assert their rights. In our good Senor Madero I saw the one who should lead the common people out of their bondage. I went to him and offered him all the wealth at my command. He accepted the trust and we began our work. It was at that time that I placed the money with Don Esteban. Also the box, containing the secret of the mine, of which only I and Madero knew. "You all know what has happened since that time. Madero won, but he was betrayed. His betrayer now seeks to rule the republic, but he can never do it. He must be overthrown." The aged man became greatly excited and the physician cautioned him to be careful. In a few minutes he became more peaceful and continued: "I have always been a great friend of the Americans. I admired their integrity and their government. I spent many years of my youth in the United States. I have known many of their great men. I was sure they would be pleased with Madero, and they were. But after he was betrayed, then I began to fear them, as I was told that the usurper, Huerta, had been helped by them." "Who told you that?" asked Billie, almost without thinking. "That man there," and Santiago pointed with his long bony finger at the mountebank, Strong. "That man, Francisco Rodriguez, who claims to be an American, but who is a traitor to his country. He fed me with lies, as I now know, and he wormed out of me the secret of Montezuma's Mine." Again the aged man's excitement nearly overcame him, but again he rallied with an almost superhuman effort.