All at once, as the Curlytops were riding along, they heard what they thought was a whistle.
"Some one is calling us," said Janet, turning to look back. "Did you hear that, Ted?"
"Yes, I heard a whistle. Maybe it's Uncle Frank, or some of the cowboys."
The children looked across the prairie but could see no one. They were about to go on again when the whistle sounded once more.
"That is some one calling us," declared Jan. "Let's see if we can't find who it is, Teddy."
So the children looked around again, but no one was in sight, and, what was still stranger, the whistling sound kept up.
"It's some one playing a joke on us, and hiding after they whistle," said Janet. "Maybe one of the cowboys from the ranch."
"Maybe an Indian," said Ted, and then he was sorry he had said that, for his sister looked frightened.
"Oh!" said Janet, "if it's an Indian—"
"I don't guess it is," Teddy hastened to say. "I guess Indians don't whistle, anyhow."