I may have mentioned the fact before, but on this occasion it became so peculiarly evident to me that I am constrained to record it here—­ I refer to the sense of impending danger which invariably preceded a visit from Fu-Manchu.  Even had I not known that an attempt was to be made that night, I should have realized it, as, strung to high tension, I waited in the darkness.  Some invisible herald went ahead of the dreadful Chinaman, proclaiming his coming to every nerve in one’s body.  It was like a breath of astral incense, announcing the presence of the priests of death.

A wail, low but singularly penetrating, falling in minor cadences to a new silence, came from somewhere close at hand.

“My God!” hissed Guthrie, “what was that?”

“The Call of Siva,” whispered Smith.

“Don’t stir, for your life!”

Guthrie was breathing hard.

I knew that we were three; that the hotel detective was within hail; that there was a telephone in the room; that the traffic of the Embankment moved almost beneath us; but I knew, and am not ashamed to confess, that King Fear had icy fingers about my heart.  It was awful—­that tense waiting—­for—­what?

Three taps sounded—­very distinctly upon the window.

Graham Guthrie started so as to shake the bed.

“It’s supernatural!” he muttered—­all that was Celtic in his blood recoiling from the omen.  “Nothing human can reach that window!” “S-sh!” from Smith.  “Don’t stir.”

The tapping was repeated.

Smith softly crossed the room.  My heart was beating painfully. 
He threw open the window.  Further inaction was impossible. 
I joined him; and we looked out into the empty air.

“Don’t come too near, Petrie!” he warned over his shoulder.

One on either side of the open window, we stood and looked down at the moving Embankment lights, at the glitter of the Thames, at the silhouetted buildings on the farther bank, with the Shot Tower starting above them all.

Three taps sounded on the panes above us.

In all my dealings with Dr. Fu-Manchu I had had to face nothing so uncanny as this.  What Burmese ghoul had he loosed?  Was it outside, in the air?  Was it actually in the room?

“Don’t let me go, Petrie!” whispered Smith suddenly. 
“Get a tight hold on me!”

That was the last straw; for I thought that some dreadful fascination was impelling my friend to hurl himself out!  Wildly I threw my arms about him, and Guthrie leaped forward to help.

Smith leaned from the window and looked up.

One choking cry he gave—­smothered, inarticulate—­and I found him slipping from my grip—­being drawn out of the window—­drawn to his death!

“Hold him, Guthrie!” I gasped hoarsely.  “My God, he’s going!  Hold him!”

My friend writhed in our grasp, and I saw him stretch his arm upward.  The crack of his revolver came, and he collapsed on to the floor, carrying me with him.