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," assented 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 passed 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
passed under him at fu