Jerry Shiels travelled with a “pardner”--a man who played the harp and acted as his assistant and messenger in affairs wherein Jerry was reluctant to appear personally. When Shiels was arrested, he had in his possession a quantity of printed and manuscript music, and after his first remand his “pardner,” Jimmy Snape, applied for the music to be given up to him, in order, as he explained, that he might earn his living. No objection was raised to this, and Shiels was quite willing that Snape should have it, and so it was handed over. Now among the music was a small slip, headed “Flitterbat Lancers,” which Shiels had shown to Snape before the arrest. In case of Shiels being taken, Snape was to take this particular slip to Legg as fast as he could. The slip indeed carried about it, in some unexplained way, which Legg understood, an indication of the place in which Shiels had concealed the bulk of the Wedlake jewels, and the whole proceeding was an ingenious trick invented by Shiels (and used before, it was supposed) to communicate with Legg while under arrest. Snape got the music, but, as chance would have it, on that very day Legg himself was arrested, and soon after was sentenced also to a term of years. Snape hung about in London for a little while, and then emigrated. Before leaving, however, he gave the slip of music to Luker’s father, a rag-shop keeper, who was a friend of his, and to whom he owed money. He explained its history, and hoped that Luker senior would be able to recoup himself for the debt, and a good deal over. Then he went. Luker senior had made all sorts of fruitless efforts to get at the information concealed in the paper. He had held it to the fire to bring up concealed writing, had washed it, had held it to the light till his eyes ached, had gone over it with a magnifying glass--all in vain. He had got musicians to strum out the notes on all sorts of instruments--backwards, forwards, alternately, and in every other way he could think of. If at any time he fancied a resemblance in the resulting sound to some familiar song-tune, he got that song and studied all its words with loving care, upside-down, right-side up--every way. He took the words “Flitterbat Lancers” and transposed the letters in all directions, and did everything else he could think of. In the end he gave it up, and died. Now lately, Luker junior had been impelled with a desire to see into the matter. He had repeated all the parental experiments, and more, with chemicals, and with the same lack of success. He had taken his “pal” Birks into his confidence, and together they had tried other experiments still--usually very clumsy ones indeed--till at last they began to believe that the message had probably been written in some sort of invisible ink which the subsequent washings and experiments had erased altogether. But he had done one other thing: he had found the house which Shiels rented at the time of his arrest, and in which a