Bradys!" exclaimed the boy.

He took off his cap and his companion stripped off a wig and false beard.

Every one in the room glanced at them in amazement.

No one suspected their identity before.

Old King Brady was now seen to have white hair and a clean-shaven face, in which a daring, determined character was shown.

Even the Collector was astonished.

When he recovered his composure, a smile crossed his face, and he rose and warmly shook hands with the pair, saying:

"Well, this is an agreeable surprise."

Old King Brady smiled, took a chew of tobacco and replied:

"You got our chief to assign us on this case and requested us to be here at two o'clock, and here we are."

"Ready for work?"

"Yes, sir. Instruct us."

"Well, all I can tell you is that this country is being flooded with precious stones upon which no duty is being paid, and I want you to find the party who is doing the crooked work."

"Have you any clews upon which we can work?"

"None, whatever. You'll have to get them yourselves from the importers in John street, Broadway and Maiden Lane. They may give you some points."

"We shall follow your suggestion."

The two detectives started for the door, then paused.

Harry Brady, the boy, then said:

"Mr. Gibson has some doubts about our ability to work for the Custom House. Since he has flung defiance at us, we'll accept his challenge."

"How? growled the inspector, in ugly tones.

"Well, we'll meet you officers and the Collector on board the steamer Campania, of the Cunard line, in one hour, when she reaches her pier from Quarantine. If we don't show up more smugglers than you do, we'll give up this assignment."

"I'll go you!" eagerly exclaimed the jealous inspector.

"And I'll be there to see that you get fair play," grimly said the Collector.

The Bradys silently bowed and withdrew.

When they reached the street, Old King Brady laughed and said:

"They're all jealous of us. But we'll show them a trick or two, Harry."

"They'll be a surprised lot," laughed the boy. "We have them beaten already."

They headed for the jewelry district and called upon several of the most prominent importers and lapidaries, from whom they gained some very valuable information. The last importer they spoke to said:

"Paul La Croix, a French-Canadian, was just in here with his daughter, trying to sell us some smuggled diamonds. See—there he goes now."

He pointed out the window at a tall, thin, stylishly-clad man of forty in light trousers, a black frock coat and high hat.

The detectives observed that he now did not have his daughter with him.

From where they were, they could see that La Croix had a thin, sallow face, a long, sharp nose and a closely-trimmed dark moustache.

He turned into Broadway and disappeared in the crowd.

"Who is he?" asked Old King Brady, of the dealer in precious stones.

"A mystery. No one knows. He makes many trips between New York and Havre to smuggle diamonds which he sells here. Every jeweler in the Lane knows him. Some deal with him."

"Where does he live?"

"At the Fifth Avenue Hotel."

"Thank you."

And a moment later the detectives were gone.

Reaching Broadway they hurried ahead intending to find La Croix and arrest him with contraband diamonds in his possession.

But the man disappeared and they found no trace of him.

The Bradys gave up the hunt, temporarily, for they were determined to find the man again.

They crossed the city, going to the west side.

People who saw the pair paid no heed to them now, for they had made some changes in their apparel, in a sheltering doorway, and by turning their coats inside out, pocketing their uniform hats and putting on soft felt hats, they transformed their appearance.

They now looked like ordinary citizens.

Each one adjusted a false moustache and a wig to hide his identity.