"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 superstition 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 passed out from the New Louvre Hotel, crossed the busy thoroughfare and entered the buffet of an establishment not far distant. My friend having ordered cocktails-- "And now perhaps you will explain to me the reason for your mysterious behavior?" said I. Smith, placing my glass 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?" "For a very good reason, Petrie, and the same that prompts me to retain the Tûlun-Nûr box in my own possession rather than to deposit it in the strong-room of my bank." "I begin to understand." "I trust you do, Petrie; it is fairly obvious. Probably the plan is a perilous one, but I hope, by laying myself open to attack, to apprehend the enemy--perhaps to make an important capture." Setting down my glass, I stared in silence at Smith.