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:—