Tad tried to sing, but gave it up and resumed his whistling.
"I'm glad Chunky is not out on this trick," thought the boy aloud. "I am afraid he would be riding back to camp as fast as his pony could carry him."
No sooner had the words left his mouth than a flash, so brilliant that it blinded Tad for the moment, lighted up the prairie. A crash which, as it seemed to him, must have split the earth wide open, followed almost instantly.
Another roar, different from that caused by the thunder, rose on the night air, accompanied by the suggestive rattle of meeting horns and the bellowing of frightened cattle.
By this time Tad had circled around to the west side of the herd. The instant this strange, startling noise reached him he halted his pony and listened.
Off to the north of him he saw the flash of a six-shooter. Another answered it from his rear. Then a succession of shots followed quickly one after the other.
The lad began slowly to understand.
He could hear the rush and thunder of thousands of hoofs.
"The cattle are stampeding!" cried Tad.