which found its way into the St. Louis headquarters and which appeared to be a code letter written in Greek characters and words. An inspection of this, and a close following through of the case in all the hands it reached, will give a reader some idea of the uncanny sureness of the United States government experts in deciphering any sort of blind communication that may come before them.
The average unskilled person could make little out of the original letter, which was worse than Greek. Interest in this puzzle deepened when it was discovered that, although written in Greek characters, Greek scholars to whom it was submitted were unable to translate it. It was ultimately sent to the War College in Washington, that House of Mystery, which in due time returned a German translation, revealing the fact that Greek letters had been adapted to the formation of German words. It might still have remained possible for the real secret of the letter to have been concealed in an unknown code—as one may learn by reference to the brief mention of ciphers and codes in an earlier chapter (See "Arts of the Operatives"). Therefore, a first-class mystery story, indeed the best detective story of all those the League chiefs have sent in, still remains for any wise doctor who can solve it. It is easier to write a "detective story" than it is to read a cipher and double code, because a story-writer knows his own answer, whereas in the other case, no one knows the real answer.
This letter had been stopped in transit in France a few days after the entrance of the United States into the Great War. There seemed to be some small hope of finding a clue to the author through advertising it as an undelivered letter. While this plan was under contemplation, however, a report reached headquarters, from an operative, to the effect that while soliciting Y. M. C. A. subscriptions in a St. Louis office building late at night, he had surprised a citizen of German origin, alone in his office, who appeared to be attempting to decipher a letter with the aid of two books, seemingly code books.
The letter was then advertised and two operatives were assigned to watch the appropriate window at the General Post Office. After a week's vigil, the clerk in charge beckoned to the operatives and pointed to the retreating figure
