"Here's Mr. Kane now!" cried Nan, halting before the grim-visaged
horseman. "Good-morning, Mr. Kane!"

The man's lips twisted into a smile, and he nodded. But no word
came from him. Nan was not to be put off easily. She asked:

"Do you know what that sound is, Mr. Kane? Do listen to it!" as the
high-pitched whistle again reached their ears.

Hesitation Kane struggled to answer--and it was a struggle. They
could see that. He flushed, and paled, and finally blurted out a
single word:

"Outlaw!"

With that he strode by and was lost in the shadows of the trees.
Nan and Walter gazed at each other in both amazement and amusement.

"What do you know about that?" demanded the boy.

"Well, we got him to say something," sighed the girl.

"But--but it doesn't mean anything. 'Outlaw,' indeed! Does he mean
to tell us that there is a Mexican bandit, for instance, out there
whistling?"

"How foolish!" laughed Nan. "Of course not."

"Then, Miss Sherwood, please explain," commanded Walter.