ll speed.

"This way, Kara--hey, Karo," called out Zeph, and the two strange lads
came up to him with a fawn-like docility, in keeping with the mild,
timid expression of their faces.

"Sare," spoke one of them with a bow, and his companion repeated the
word. They both bowed to Ralph next, and stood like obedient children
awaiting orders. Ralph was silent for fully a minute, studying their
unfamiliar make-up. At that moment Fred Porter, having come down
stairs the front way, strolled around the corner of the house.

"This is my friend, Fred Porter--Zeph--Zeph Dallas, Porter,"
introduced the young railroader, and the two boys shook hands. Porter
became instantly interested in the two strange lads.

"I'm going to show you fellows something," said Zeph, "something
mighty remarkable, something you never saw before, and it's going to
beat anything you ever heard of. About those two boys. Kara!"

One of the two lads instantly moved to the side of Zeph, who beckoned
to him to follow him. He led the boy ten feet away behind a thick
large bush, his back to the others.

"Karo," he spoke again, and the other boy allowed him to turn him
around where he stood, his back to the other boy.

"See here, Zeph," spoke Ralph with a broad smile, "are you going to
give us a detective demonstration of some kind, or a sleight-of-hand
demonstration?"

"Quit guying me, Ralph Fairbanks," said Zeph. "You're always at it,
but I'm going to give you something this time that will make you sit
up and take notice, I'll bet. Those boys came from a good many
thousand miles away--from the other side of the world, in fact."

"They look it," observed Fred Porter.

"Gomera," exclaimed Zeph.

"Where's that now?" inquired Fred.

"It is the smallest of the Canary Islands."

"Oh, that's it!"

"And they talk without saying a word," was Zeph's next amazing
announcement.

"Whew!" commented Fred dubiously.

"They do. It's that I'm going to show you. Perhaps those boys are the
only two of their kind in the United States. They are Silvandos."

"What are Silvandos, Zeph?" inquired Ralph.

"Silvandos," replied Zeph, with manifest enjoyment of the fact that he
was making a new and mystifying disclosure, "are persons who carry on
a conversation through a whistling language."

CHAPTER XVI

ZEPH DALLAS AND HIS "MYSTERY"

"Whistling language?" repeated Fred Porter. "Is there one?"

"Aha! didn't I say I was going to show you something you nev