“Inspector Weymouth?”

“Oh! for once he has stooped to a disguise:  spectacles, and a muffler which covers his face right up to the tip of his nose.  Add to this a prodigious overcoat and an asthmatic cough, and you have a picture of Mr. Jonathan Martin, the occupant of room No. 239.”

I could not repress a smile upon hearing this description.

“No. 239,” continued Smith, “contains two beds, and Mr. Martin’s friend will be joining him there this evening.”

Meeting my friend’s questioning glance, I nodded comprehendingly.

“Then what part do I play?”

“Ostensibly we both leave town this evening,” he explained; “but I have a scheme whereby you will be enabled to remain behind.  We shall thus have one watcher inside and two out.”

“It seems almost absurd,” I said incredulously, “to expect any member of the Yellow group to attempt anything in a huge hotel like the New Louvre, here in the heart of London!”

Nayland Smith, having lighted his pipe, stretched his arms and stared me straight in the face.

“Has Fu-Manchu never attempted outrage, murder, in the heart of London before?” he snapped.

The words were sufficient.  Remembering black episodes of the past (one at least of them had occurred not a thousand yards from the very spot upon which we now stood), I knew that I had spoken folly.

Certain arrangements were made then, including a visit to Scotland Yard; and a plan—­though it sounds anomalous—­at once elaborate and simple, was put into execution in the dusk of the evening.

London remained in the grip of fog, and when we passed along the corridor communicating with our apartments, faint streaks of yellow vapor showed in the light of the lamp suspended at the further end.  I knew that Nayland Smith suspected the presence of some spying contrivance in our rooms, although I was unable to conjecture how this could have been managed without the connivance of the management.  In pursuance of his idea, however, he extinguished the lights a moment before we actually quitted the suite.  Just within the door he helped me to remove the somewhat conspicuous check traveling-coat which I wore.  With this upon his arm he opened the door and stepped out into the corridor.

As the door slammed upon his exit, I heard him cry:  “Come along, Petrie! we have barely five minutes to catch our train.”

Detective Carter of New Scotland Yard had joined him at the threshold, and muffled up in the gray traveling-coat was now hurrying with Smith along the corridor and out of the hotel.  Carter, in build and features, was not unlike me, and I did not doubt that any one who might be spying upon our movements would be deceived by this device.

In the darkness of the apartment I stood listening to the retreating footsteps in the corridor.  A sense of loneliness and danger assailed me.  I knew that Inspector Weymouth was watching and listening from the room immediately opposite; that he held Smith’s key; that I could summon him to my assistance, if necessary, in a matter of seconds.