The office boy sauntered along, with nothing apparently on his mind,
and finally stopped in front of a window on Union Square, which
appeared to have considerable attraction for him.

Then it was that the detective saw Ralston come up, and, while
apparently watching the window also, thrust his hand into the pocket of
the office boy and withdraw the package of money, which he at once
slipped into his own pocket.

Mr. Sharpleigh smiled a little to himself.

"Very neat!" he soliloquized, "but it won't go down, my cunning
friend."

Felix gave a little side glance, seeing what was going on, but
immediately stared again in at the window.

Sharpleigh beckoned to a tall man, dressed as a civilian, but really an
officer in plain clothes.

"Go after him!" he said, in a low voice, indicating Ralston.

Then he followed Felix, who in about five minutes began to show signs
of agitation.

He thrust his hand wildly into his pocket, and looked panic-stricken.

"What is the matter, my boy?" asked Sharpleigh, blandly.

"Oh, sir, I have been robbed," faltered Felix.

"Robbed--of what?"

"I had eighteen hundred dollars in bank bills in my pocket, in four
parcels, and--and they must have been taken while I was looking in at
this window."

"You seem to have been very careless?" said Sharpleigh. "Why were you
not more careful when you knew you had so much money in your care?"

"I--I ought to have been, I know it, sir, but I wasn't thinking."

"Where are you employed?"

"At Mr. Fairchild's office, on Fourteenth Street."

"The real estate agent?"

"Yes, sir."

"I know the place."

"My cousin is the bookkeeper. He will be so angry with me."

"I think he will have reason. I saw a man following you rather closely,
I presume he took the money."

"Oh, won't you come back to the office with me and tell my cousin that?
I am afraid he will discharge me."

"Yes, I will go with you."

So it happened that Felix and Mr. Sharpleigh went together into the
office where Mullins was eagerly waiting for the return of his
emissary.

"What's the matter, Felix?" he said, as the boy entered. "Have you
brought the money?"

"Oh, Cousin David, I am so sorry."

"So sorry? For what?"

"I--I have lost the money. A pickpocket took it while I was looking in
at a window. This gentleman was near and he saw a suspicious-looking
man next to me."

"This is a strange story, Felix. We must notify the police at once. Did
you see anyone likely