"Look out! Look out!" he cried. "There's a stampede of 'em, and they're headed right this way!"
"Stampede of what? Who's headed this way?" cried Tom. "A lot of monkeys?"
"No, wild horses! Thousands of 'em! Hear 'em coming?"
In the silence that followed Ned's warning there could be heard a dull, roaring, thundering sound, and the earth seemed to tremble.
"The young senor speaks truth! Wild horses are coming!" cried San Pedro. "Get ready, senors! Have your weapons at hand, and perchance we can turn the stampede aside."
"The rifles! The electric rifles, Ned—Mr. Damon! We've got to stop them, or they'll trample us to death!" cried Tom.
As he spoke the thundering became louder, and then, looking across the grassy plain, all saw a large troop of wild horses, with flying manes and tails, headed directly toward them!
