Smith setting out for New Scotland Yard in order to make certain final arrangements in connection with the business of the night, I began closely to study the mysterious Zagazig messages, determined not to be beaten, and remembering the words of Edgar Allan Poe—­the strange genius to whom we are indebted for the first workable system of deciphering cryptograms:  “It may well be doubted whether human ingenuity can construct an enigma of the kind which human ingenuity may not, by proper application, resolve.”

The first conclusion to which I was borne was this:  that the letters comprising the word “Zagazig” were designed merely to confuse the reader, and might be neglected; since, occurring as they did in regular sequence, they could possess no significance.  I became quite excited upon making the discovery that the punctuation marks varied in almost every case!

I immediately assumed that these constituted the cipher; and, seeking for my key-letter, e (that which most frequently occurs in the English language), I found the sign of a full-stop to appear more frequently than any other in the first message, namely ten times, although it only occurred thrice in the second.  Nevertheless, I was hopeful ... until I discovered that in two cases it appeared three times in succession!

There is no word in English, nor, so far as I am aware, in any language, where this occurs, either in regard to e or any other letter!

That unfortunate discovery seemed so wholly to destroy the very theory upon which I relied, that I almost abandoned my investigation there and then.  Indeed, I doubt if I ever should have proceeded were it not that by a piece of pure guesswork I blundered on to a clue.

I observed that certain letters, at irregularly occurring intervals, were set in capital, and I divided up the message into corresponding sections, in the hope that th capitals might indicate the commencements of words.  This accomplished, I set out upon a series of guesses, basing these upon Smith’s assurance that the death of the dacoit afforded a clue to the first message and the note which he (Smith) had pinned upon the door a clue to the second.

Such being my system—­if I can honor my random attempts with the title—­I take little credit to myself for the fortunate result.  In short, I determined (although e twice occurred where r should have been!) that the first message from the thirteenth letter, onwards to the twenty-seventh (id est: I;g:-zagAz;i-;_g_;_-Z_,-a;-gazi;-) read:—­

"Three Colt Street."

Endeavoring, now, to eliminate the e where r should appear, I made another discovery.  The presence of a letter in italics altered the value of the sign which followed it!

From that point onward the task became child’s-play, and I should merely render this account tedious if I entered into further details.  Both messages commenced with the name “Smith” as I early perceived, and half an hour of close study gave me the complete sentences, thus:—­