"Don't it say 'Special'?" demanded Zeph, with an offended air.

"Yes, I see the word."

"Well, then, that's me--special secret service, see? Of course, I don't look much like a detective, just common and ordinary now, but I'm going to buy a wig and a false beard, and then you'll see."

"Oh, Zeph!" exclaimed Ralph.

"All right, you keep right on laughing at me," said Zeph. "All the same, I'm hired. What's more, I'm paid. Look at that--I've got the job and I've got the goods. That shows something, I fancy," and Zeph waved a really imposing roll of bank notes before the sight of the young engineer.

"Your employers must think you a pretty good man to pay you in advance," suggested Ralph.

"They do, for a fact," declared Zeph. "They know they can depend upon me. Say, Ralph, it's funny the way I fell into the job. You never in your life heard of the slick and easy way I seemed to go rolling right against it. And the mystery, the deadly secrets, the--the--hold on, though, I'm violating the eth--eth--yes, ethics of the profession."

"No, no--go on and tell us something about it," urged Ralph. "I'm interested."

"Can't. I've gone too far already. Sworn to secrecy. Honestly, I'm not romancing, Ralph, I'm working on a case that reads like a story book.

Some of the strange things going on--they fairly stagger me. I can't say another word just now, but just the minute I can, you just bet I'll tell you all about it, Ralph Fairbanks. Say, you haven't seen two boys around here, have you--two tiny fellows? I left them in the garden here. They're in my charge, and I mustn't lose sight of them,"

and Zeph began looking all around the place.

"Two human monkeys, who make no more of flying through the air than you or I do to run a race?" inquired Ralph.

"That's them," a.s.sented Zeph.

"They were here a few minutes ago," advised Ralph, "but I don't see them just now. I wondered who they were. The last I saw of them, they were chasing one another over our neighbors' lot over there."

"I must find them," said Zeph. "They are another of my responsibilities. I hear them."

As Zeph spoke, there proceeded from the alley a mellow and peculiar but very resonant whistle. It was followed by a responsive whistle, clear as a calliope note. Then into view dashed the two boys for whom Zeph was looking. They were still chasing one another, and the foremost of the twain was making for the house. As he pa.s.sed a tree full tilt, without the least apparent exertion he leaped up lightly, seized a branch, coiled around it like a rubber band, and his pursuer pa.s.sed under him at full 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 never heard of before? You bet there is a whistling language!" chuckled Zeph--"and I'm now about to demonstrate it to you. You see these two boys? Well, they are natives of Gomera, the smallest of the Canary Islands. They were raised in a district where at times there is no living thing within sight, and the vast wilderness in the winding mountains is broken only by the crimson flower of the cactus growing in the clifts of the rock."

"You talk like a literary showman, Zeph Dallas," declared Fred.

"Well, I'm telling the story as I get it, ain't I?" demanded Zeph in an injured tone and with a sharp look at Fred, as if he suspected that he was being guyed. "Anyhow, I want to explain things so you'll understand."

"Go right ahead, Zeph," insisted Ralph encouragingly, "we're interested."

"Well, up among those big stone terraces is the whistling race. They are able to converse with one another at a distance of three miles."

"That's pretty strong," observed Fred. "But make it three miles."

"A Silvando will signal a friend he knows to be in a certain distant locality. He does it by setting his fore fingers together at a right angle in his mouth, just as you'll see these two Canaries do in a minute or two. An arrow of piercing sounds shoots across the ravine."

"Arrow is good--shoots is good!" whispered Fred, nudging Ralph.

"There is a moment's pause--" continued Zeph.

"Oh, he's read all this in some book!" declared Fred.

"Then there comes a thin almost uncanny whistle from far away.

Conversation begins, and as the sounds rise and fall, are shrill or drawn, so they are echoed. Then comes the ghostly reply, and then question and answer follows. They talk--all right. Travelers say so, and a lot of scientific fellows are now on the track of this strange tribe to investigate them before civilization makes of their talk a dead language. Kara--ready!" called out Zeph to the boy at the bush.