When Nat came back from lunch he was introduced to Harry Bray, and Hamilton Dart brought forth several packages of old bills and letters and also a couple of cheap blank books.

"I want these things sorted out," said he. "Enter all names in the books, and file them away according to date."

This seemed easy work, and both of the young clerks said they understood what was wanted. Then Hamilton Dart put on his hat and left the office.

"I won't be back this afternoon," he said. "Lock up at five o'clock, and you, Bray, can take the key."

"Yes, sir," answered Harry Bray.

"This isn't very hard," was Nat's comment, when he was left alone with his fellow clerk.

"It is about as easy a job as I ever struck," answered Harry Bray.

"It's queer there are no customers coming in," said Nat, an hour later. "Mr. Dart must do most of his business outside."

"A good many brokers do, Nat. They have to hustle for business or they don't get any."

The afternoon passed, and at the proper time Nat left the office and went home.

"You've certainly struck a soft snap," said Dick, when the country boy had related his experience. "Wish I could strike a snap like that."

"Perhaps you will some day," answered Nat. "Come, I'll give you a lesson in writing and figures to-night," and he did. Dick was a bright scholar, so it proved a pleasure more than a task to teach him.

Promptly on time the following morning, Nat went to the office. At the door he met Harry Bray, who had just come in from his home on Staten Island. They opened up the office together, one doing the sweeping and the other the dusting.

"In most places like this, the office boy or the janitor does such work," said Harry.

"I don't mind it in the least," answered Nat.

"Oh, neither do I."

They began on their work where they had left off, and about an hour later their employer put in an appearance.

"Hard at it, eh?" he said, cheerily. "That's the way I like to see things move. Nat, I want you to go to the post office again."

"Yes, sir."

In a few minutes our hero had departed, and then Hamilton Dart turned to Harry Bray.

"Bray, here is an important document to deliver to a party living near Central Park," said he. "Deliver it, and get a receipt."

"I will, sir," answered Harry Bray, and in a minute more he, too, was gone.

An hour later there was a knock on the door, and the sick man, who had called the day before, came in.

"Is that situation still open?" he questioned, anxiously.

"Why do you ask?" demanded Hamilton Dart, abruptly.

"I was going to say that I borrowed that money from my sister."

"Oh! Have you it with you?"

"Yes, sir."

"Then, if you wish the job, you can take it right now. Another man is coming to see me about it in an hour."

"I'll take the job," said Oliver Ripple, quickly, and brought forth his money. Hamilton Dart took it, and gave his usual receipt.

"What interest do I get on this?" asked the new clerk, anxiously.

"Six per cent."

"Thank you. I told my sister I thought as much. She had the money in the bank, but that only paid her three per cent. Six per cent. will be twice as good."

"You may come to work to-morrow morning at nine," said Hamilton Dart.

"I'll go to work to-day, if you say so, Mr. Dart."

"No, my other clerks can take care of the work to-day. Both of them are now out on errands."

When Oliver Ripple was gone, Hamilton Dart smiled broadly to himself.

"Three of them," he murmured. "That's not so bad, after all. I wonder if that chap who was to come at half-past ten will show up?"

When Nat left the post office he found no letters for Samuel Barrows.

"Mr. Dart will be disappointed again," he thought. "But it is not my fault."

The afternoon passed quietly. Only one man called at the office, and when he found Hamilton Dart was not in he disappeared immediately.

That evening Nat gave Dick another lesson, for which the newsboy was very grateful.

"No wonder you got that job," said Dick. "You can figure like lightning, and write fine, too."

"I don't have to figure much at the office."

"How do you like your boss?"

"I haven't really seen enough of him to make up my mind."

"He must be full of business."

"I suppose that is so."

When Nat went to the office on the following day he again met Harry Bray at the entrance. They went upstairs together, and found two men standing in the hallway, near the door of the office. As soon as they entered the place the men followed them.

"Neither of these young chaps is the man," said one of the newcomers, in a low voice.

"Where is Mr. Hamilton Dart?" asked the other.

"I can't say, sir," answered Harry Bray. "He may be here shortly."

"Are you a partner in this concern?"

"No, sir. I am a clerk."

"Are you a clerk, too?" asked the man, turning to Nat.

"Yes, sir. Is there anything we can do for you?"

"Don't know as there is, young man," was the short answer. "We'll wait here for Mr. Dart."

A half-hour passed and Oliver Ripple put in an appearance.

"Where is Mr. Dart?" he asked, gazing around.

"He is not here yet," answered Nat.

"I am his new clerk. He engaged me yesterday, and told me to come to work this morning."

At this speech the two men who had come in gazed at the sick man curiously.

"So you were engaged yesterday?" asked one in a low tone.

"Yes."

"Excuse me, but I'd like to know if you put up any money as security?"

"I did—a hundred dollars."

"Ah!" And each of the two men looked at his companion significantly.

"Do you know Mr. Dart?" asked the sick man.

"We know of him."

"He does quite a business, doesn't he?"

"He does—in his own way," was the suggestive answer.

At that moment came a tramping on the stairs. Then the office door was thrown open, and Hamilton Dart appeared.

"There he is!" cried one of the men. "Just as I thought!"

He started for the doorway, but Hamilton Dart was too quick for him. He backed away, leaped for the stairs, and went down flight after flight, four and five steps at a time. Both men gave chase, but by the time they reached the sidewalk the swindler had disappeared.

"Hullo! what can this mean?" cried Nat, in quick alarm. "I must say I don't like this."

"Those men are after Mr. Dart," came from Harry Bray.

"You mind the office—I'll see what is up," went on Nat, and followed down the stairs.

"He is gone, Parsons," said one of the men.

"You are sure it was our man?"

"Yes, confound the luck. He got away like a slippery eel."

"Did Mr. Dart run away from you?" asked Nat.

"That's what he did, young man."

"What did he run for?"

"Perhaps you know as well as I do."

"No, I don't."

"How long have you worked for that man?"

"Only a few days."

"What about that other chap upstairs?"

"He came to work about the time I did."

"And that pale-looking man, too?"

"I don't know any more about him than you do."

"Did you place any money in your employer's hands?"

"Yes, a hundred dollars. And Harry Bray, the other clerk, put up the same amount."

"Humph! I reckon you've seen the last of your cash."

"What!" cried Nat, aghast. "Do you mean that?"

"I sure do."

"But—but——" Our hero was so staggered he could not continue for the moment.

"This Hamilton Dart—or whatever he calls himself—is a first-class swindler."

"A swindler!" Nat fell up against the doorway. "I—I—then my money is gone?"

"More than likely."

"Oh, what a fool I've been! And I thought he was such a gentleman."

"He has fooled lots of folks besides you, young man," said one of the men, kindly, for he saw that Nat was hard hit.

"He isn't a business man at all?"

"He is a confidence man from Chicago."

By this time, feeling certain something was wrong, Harry Bray and Oliver Ripple came below.

"What do you mean by confidence man?" asked Nat, doubtfully.

"He is a swindler; one of the kind that can tell a good story in order to get your money."

"Who is a swindler?" demanded Harry Bray.

"Our employer," cried Nat. "He has run away with our money."

"Has Mr. Dart run away?" asked the sick man, nervously.

"Yes."

"Oh! And to think I borrowed that money from my poor sister!" came with a cry of anguish, and then the sick man sank on the hallway stairs, thoroughly overcome.