Six hours later Barlow entered the chief's office in the Treasury Department and reported that he had secured the code message. "So New York phoned," was the only comment from the man who directed the destinies of the Secret Service. "Take it right up to the Navy Department and turn it over to Thurber, the librarian. He'll be able to read it, if anybody can." Thurber, Gene knew, was the man who was recognizedly the leading authority on military codes and ciphers in the United States, the man who had made a hobby as well as a business of decoding mysterious messages and who had finally deciphered the famous "square letter" code, though it took him months to do it. "He'll have to work faster than that this time," thought Barlow, as he made his way toward the librarian's office on the fourth floor of the big gray-stone building. "Time's at a premium and Germany moves too fast to waste any of it." But Thurber was fully cognizant of the necessity for quick action. He had been warned that Barlow was bringing the dispatch and the entire office was cleared for work. Spreading the oiled paper on a table top made of clear glass, the Librarian turned on a battery of strong electric lights underneath so that any watermark or secret writing would have been at once apparent. But there was nothing on the sheet except line after line of meaningless letters. "It's possible, of course, that there may be some writing in invisible ink on the sheet," admitted the cipher expert. "But the fact that oiled paper is used would seem to preclude that. The code itself may be any one of several varieties and it's a matter of trying 'em all until you hit upon the right one." "I thought that Poe's story of 'The Gold Bug' claimed that any cipher could be read if you selected the letter that appeared most frequently and substituted for it the letter 'e,' which is used most often in English, and so on down the list," stated Barlow. "So it did. But there are lots of things that Poe didn't know about codes." Thurber retorted, his eyes riveted to the sheet before him. "Besides, that was fiction and the author knew just how the code was constructed, while this is fact and we have to depend upon hard work and blind luck. "There are any number of arbitrary systems which might have been used in writing this message," he continued. "The army clock code is one of them--the one in which a number is added to every letter figure, dependent upon the hour at which the message is written. But I don't think that applies in this case. The cipher doesn't look like it--though I'll have to admit that it doesn't look like any that I've come across before. Let's put it on the blackboard and study it from across the room. That often helps in concentrating." "You're not going to write the whole thing on the board?" queried the operative. "No, only the first fifteen letters or so," and Thurber put down this line: I i i t f b b t t x o r q w s b b