1. Smith passing Three Colt Street twelve-thirty Wednesday.

2. Smith going Joy-Shop after one Monday.

The word “Zagazig” was completed, always, and did not necessarily terminate with the last letter occurring in the cryptographic message.  A subsequent inspection of this curious code has enabled Nayland Smith, by a process of simple deduction, to compile the entire alphabet employed by Dr. Fu-Manchu’s agent, Samarkan, in communicating with his awful superior.  With a little patience, any one of my readers my achieve the same result (and I should be pleased to hear from those who succeed!).

This, then was the outcome of my labors; and although it enlightened me to some extent, I realized that I still had much to learn.

The dacoit, apparently, had met his death at the very hour when Nayland Smith should have been passing along Three Colt Street—­a thoroughfare with an unsavory reputation.  Who had killed him?

To-night, Samarkan advised the Chinese doctor, Smith would again be in the same dangerous neighborhood.  A strange thrill of excitement swept through me.  I glanced at my watch.  Yes!  It was time for me to repair, secretly, to my post.  For I, too, had business on the borders of Chinatown to-night.

CHAPTER XXII

THE SECRET OF THE WHARF

I sat in the evil-smelling little room with its low, blackened ceiling, and strove to avoid making the slightest noise; but the crazy boards creaked beneath me with every movement.  The moon hung low in an almost cloudless sky; for, following the spell of damp and foggy weather, a fall in temperature had taken place, and there was a frosty snap in the air to-night.

Through the open window the moonlight poured in and spilled its pure luminance upon the filthy floor; but I kept religiously within the shadows, so posted, however, that I could command an uninterrupted view of the street from the point where it crossed the creek to that where it terminated at the gates of the deserted wharf.

Above and below me the crazy building formerly known as the Joy-Shop and once the nightly resort of the Asiatic riff-raff from the docks—­ was silent, save for the squealing and scuffling of the rats.  The melancholy lapping of the water frequently reached my ears, and a more or less continuous din from the wharves and workshops upon the further bank of the Thames; but in the narrow, dingy streets immediately surrounding the house, quietude reigned and no solitary footstep disturbed it.

Once, looking down in the direction of the bridge, I gave a great start, for a black patch of shadow moved swiftly across the path and merged into the other shadows bordering a high wall.  My heart leapt momentarily, then, in another instant, the explanation of the mystery became apparent—­in the presence of a gaunt and prowling cat.  Bestowing a suspicious glance upward in my direction, the animal slunk away toward the path bordering the cutting.