Hardly had they begun the advance than Ned, who had been narrowly
watching one of the natives, hurried up to Tom, and rapidly
whispered something to his chum.

"What?" cried Tom. "Armed with a six-shooter, is he? Well, we'll see
about that! Halt!" he cried in Spanish, and then he called San Pedro
the head mule driver, to him.




CHAPTER X

A WILD HORSE STAMPEDE


"Who is that man?" demanded Tom pointing to the one Ned had
indicated. Tom's chum had had a glimpse of a shining revolver in the
hip pocket of one of the mule drivers, and knowing that the simple
natives were not in the habit of carrying such weapons, the lad had
communicated his suspicions to Tom.

"What man, senor?" asked the head mule driver.

"That one!" and the young inventor again pointed toward him. And,
now that Tom looked a second time he saw that the man was not as
black as the other drivers--not an honest, dark-skinned black but
more of a sickly yellow, like a treacherous half-breed. "Who is he?"
asked Tom, for the man in question was just then tightening a girth