"I have not yet seen the interior of the box, Mr. Smith," he said.

Smith paused in his perambulation of the carpet and stared hard at the celebrated art dealer.

"Unfortunately," he replied, "the key is missing."

"Ah!" cried the a.s.sistant, Lewison, excitedly, "you are mistaken, sir!

Coffers of this description and workmanship are nearly always complicated conjuring tricks; they rarely open by any such rational means as lock and key. For instance, the Kren treasure-chest to which I referred, opens by an intricate process involving the pressing of certain k.n.o.bs in the design, and the turning of others."

"It was ultimately opened," said Mr. Meyerstein, with a faint note of professional envy in his voice, "by one of Christie's experts."

"Does my memory mislead me," I interrupted, "or was it not regarding the possession of the chest to which you refer, that the celebrated case of 'Hague versus Jacobs' arose?"

"You are quite right, Dr. Petrie," said Meyerstein, turning to me.

"The original owner, a member of the Younghusband Expedition, had been unable to open the chest. When opened at Christie's it proved to contain jewels and other valuables. It was a curious case, wasn't it, Lewison?" turning to his clerk.

"Very," agreed the other absently; then--"Have you endeavored to open this box, Mr. Smith?"

Nayland Smith shook his head grimly.

"From its weight," said Meyerstein, "I am inclined to think that the contents might prove of interest. With your permission I will endeavor to open it."

Nayland Smith, tugging reflectively at the lobe of his left ear, stood looking at the expert. Then--

"I do not care to attempt it at present," he said.

Meyerstein and his clerk stared at the speaker in surprise.

"But you would be mad," cried the former, "if you accepted an offer for the box, whilst ignorant of the nature of its contents."

"But I have invited no offer," said Smith. "I do not propose to sell."

Meyerstein adjusted his pince-nez again.

"I am a business man," he said, "and I will make a business proposal: A hundred guineas for the box, cash down, and our commission to be ten per cent on the proceeds of the contents. You must remember," raising a fat forefinger to check Smith, who was about to interrupt him, "that it may be necessary to force the box in order to open it, thereby decreasing its market value and making it a bad bargain at a hundred guineas."

Nayland Smith met my gaze across the room; again a slight smile crossed the lean, tanned face.

"I can only reply, Mr. Meyerstein," he said, "in this way: if I desire to place the box on the market, you shall have first refusal, and the same applies to the contents, if any. For the moment if you will send me a note of your fee, I shall be obliged." He raised his hand with a conclusive gesture. "I am not prepared to discuss the question of sale any further at present, Mr. Meyerstein."

At that the dealer bowed, took up his hat from the table, and prepared to depart. Lewison opened the door and stood aside.

"Good morning, gentlemen," said Meyerstein.

As Lewison was about to follow him--

"Since you do not intend to open the box," he said, turning, his hand upon the door k.n.o.b, "have you any idea of its contents?"

"None," replied Smith; "but with my present inadequate knowledge of its history, I do not care to open it."

Lewison smiled skeptically.

"Probably you know best," he said, bowed to us both, and retired.

When the door was closed--

"You see, Petrie," said Smith, beginning to stuff tobacco into his briar, "if we are ever short of funds, here's something"--pointing to the Tlun-Nr box upon the table--"which would retrieve our fallen fortunes."

He uttered one of his rare, boyish laughs, and began to pace the carpet again, his gaze always set upon our strange treasure. What did it contain?

The manner in which it had come into our possession suggested that it might contain something of the utmost value to the Yellow group. For we knew the house of John Ki to be, if not the head-quarters, certainly a meeting-place of the mysterious organization the Si-Fan; we knew that Dr. Fu-Manchu used the place--Dr. Fu-Manchu, the uncanny being whose existence seemingly proved him immune from natural laws, a deathless incarnation of evil.

My gaze set upon the box, I wondered anew what strange, dark secrets it held; I wondered how many murders and crimes greater than murder blackened its history.

"Smith," I said suddenly, "now that the mystery of the absence of a key-hole is explained, I am sorely tempted to essay the task of opening the coffer. I think it might help us to a solution of the whole mystery."

"And I think otherwise!" interrupted my friend grimly. "In a word, Petrie, I look upon this box as a sort of hostage by means of which-- who knows--we might one day buy our lives from the enemy.

I have a sort of fancy, call it superst.i.tion if you will, that nothing--not even our miraculous good luck--could save us if once we ravished its secret."

I stared at him amazedly; this was a new phase in his character.

"I am conscious of something almost like a spiritual unrest," he continued. "Formerly you were endowed with a capacity for divining the presence of Fu-Manchu or his agents. Some such second-sight would appear to have visited me now, and it directs me forcibly to avoid opening the box."

His steps as he paced the floor grew more and more rapid. He relighted his pipe, which had gone out as usual, and tossed the match-end into the hearth.

"To-morrow," he said, "I shall lodge the coffer in a place of greater security. Come along, Petrie, Weymouth is expecting us at Scotland Yard."

CHAPTER XI

IN THE FOG

"But, Smith," I began, as my friend hurried me along the corridor, "you are not going to leave the box unguarded?"

Nayland Smith tugged at my arm, and, glancing at him, I saw him frowningly shake his head. Utterly mystified, I nevertheless understood that for some reason he desired me to preserve silence for the present. Accordingly I said no more until the lift brought us down into the lobby and we had pa.s.sed out from the New Louvre Hotel, crossed the busy thoroughfare and entered the buffet of an establishment not far distant. My friend having ordered c.o.c.ktails--

"And now perhaps you will explain to me the reason for your mysterious behavior?" said I.

Smith, placing my gla.s.s before me, glanced about him to right and left, and having satisfied himself that his words could not be overheard--

"Petrie," he whispered, "I believe we are spied upon at the New Louvre."

"What!"

"There are spies of the Si-Fan--of Fu-Manchu--amongst the hotel servants! We have good reason to believe that Dr. Fu-Manchu at one time was actually in the building, and we have been compelled to draw attention to the state of the electric fitting in our apartments, which enables any one in the corridor above to spy upon us."

"Then why do you stay?"