"In about ten minutes Paddington came along, walking as if he was in quite a hurry. He went into the tobacconist's, but he came out quicker than he had entered, and his face was a study--purple with rage one minute, and white with fear the next. I don't believe he knows yet who's tailing him, sir, but he looks as if he realized we had him coming and going. He went straight over to the little restaurant, with murder in his eye, but he only stayed a minute or two. I tailed him home to his rooms, and he stamped along at first as if he was so mad he didn't care whether he was followed or not. When he got near his own street, though, he got cautious again, and I had all I could do to keep him from catching me on his trail--he's a sharp one, when he wants to be, and he's on his mettle now." "I know the breed. He'll turn and fight like any other rat if he's cornered, but meanwhile he'll try at any cost to get away from us," Blaine responded. "You have him well covered, Ross?" "Thorpe is waiting in a high-powered car a few doors away, Vanner in a taxi, and Daly is on the job until I get back. He won't take a step to-day without being tailed," the operative answered, confidently. "Here's the cigarette box, sir. I opened it as soon as I got in the restaurant, to see if it was the real goods and not a plant, as you instructed. It's the straight tip, all right. There were no cigarettes inside, only this single sheet of paper covered with little marks--looks like music, only it isn't. I don't know much about sight-reading, but some of those figures couldn't be played on any instrument!" Henry Blaine opened the little box and drew from it the bit of folded paper, which he spread out upon the desk before him. A glance was sufficient to show him that it was another cryptic message, similar to that which Guy Morrow had found in the Brunells' deserted cottage, and which he had vainly studied until far into the night. "Very good, Ross. Get back on the job, now, and report any developments as soon as you have an opportunity." When the operative had gone, Blaine drew forth the cryptogram received the previous evening and compared the two. They were identical in character, although from the formation of the letters and figures, the message each conveyed was a different one. The first had baffled him, and he scrutinized the second with freshly awakened interest: [Illustration: An image of a coded message is shown here in the text.] The three lines fascinated him by their tantalizing problem, and he could not take his eyes from them. The musical notes could be easily read in place of letters, of course, with the sign of the treble clef as a basic guide, but the other figures still puzzled him. All at once, a word upon the lowest line which explained itself caught his eye; then another and another, until the method of deciphering the whole message burst upon his mind. One swift gesture, a few eagerly scrawled calculations, and the truth was plain to him.