"That ought to scare would-be thieves away," said Chet. "They'll imagine somebody is firing at them."
The rest for a couple of days had done Rush much good, and he made no work of carrying the two boys along the trail that led to the second foothills.
Long before noon they reached the hills, and here stopped for lunch.
"And now for the wonderful mine!" cried Chet. Then, happening to glance across the plains below, he added: "Gracious, Paul! What is that?"
The attention of both young ranchmen was at once drawn to a round, black cloud on the horizon to the east. It was hardly a yard in diameter, apparently, when first seen, but it increased in size with great rapidity.
It was moving directly toward them, and in less than two minutes from the time Chet uttered his cry it had covered fully a third of the distance.
"From what I have heard I should say that was a cyclone cloud," exclaimed Paul. "And still"
"Who ever heard of a cyclone up here among the foothills," returned Chet. "I don't believe they ever strike this territory."
