selves without fear of being overheard by the Mexicans. At first Senor Delazes had suggested that one of his own drivers pilot Tom's cart, saying:
"I know what the senors fear—that their language may be listened to, but I assure you that this man understands no English, do you, Josef?" he asked the man in question, using the Spanish.
The man shook his head, but a quick look passed between him and his employer.
"Oh, I guess we'll let Rad drive," insisted Tom calmly, "it will remind him of his mule Boomerang that he left behind."
"As the senor will," Delazes had replied with a shrug of his shoulders, and he turned away. So it was that Tom, Ned and Mr. Damon, in their own cart, piloted by the colored man, were in the rear of the little cavalcade.
"Have you any idea where you are going, Tom?" asked Ned, after they had reached the shade, when it was not such a task to talk.
"Oh, I have a good general idea," replied the young inventor. "I've studied the map Mr. Illingway sent, and according to that the city of— well, you know the place we're looking for—lies somewhere between Tampico and Zacatecas, and which the plain of the ruined temple which used to be near the ancient city of Poltec, is about a hundred and fifty miles north of the city of
