“She sells sea-shells on the sea-shore,” the vocalist wailed. “The shells she sells are sea-shells, I'm sure.” The effect was instantaneous. A window was flung open, and an indignant householder with one hand frantically waved the musicians away, and with the other threw them a copper coin. At the same moment Ford walked quickly to the piano and laid a half-crown on top of it. “Follow me to Harley Street,” he commanded. “Don't hurry. Take your time. I want you to help me in a sort of practical joke. It's worth a sovereign to you.” He passed on quickly. When he glanced behind him, he saw the two men, fearful lest the promised fortune might escape them, pursuing him at a trot. At Harley Street they halted, breathless. “How long,” Ford demanded of the one who played the piano, “will it take you to learn the accompaniment to a new song?” “While you're whistling it,” answered the man eagerly. “And I'm as quick at a tune as him,” assured the other anxiously. “I can sing----” “You cannot,” interrupted Ford. “I'm going to do the singing myself. Where is there a public-house near here where we can hire a back room, and rehearse?” Half an hour later, Ford and the piano-player entered Sowell Street dragging the piano behind them. The amateur detective still wore his rain-coat, but his hat he had exchanged for a cap, and, instead of a collar, he had knotted around his bare neck a dirty kerchief. At the end of the street they halted, and in some embarrassment Ford raised his voice in the chorus of a song well known in the music-halls. It was a very good voice, much too good for “open-air work,” as his companion had already assured him, but, what was of chief importance to Ford, it carried as far as he wished it to go. Already in Wimpole Street four coins of the realm, flung to him from the highest windows, had testified to its power. From the end of Sowell Street Ford moved slowly from house to house until he was directly opposite the three in one of which he believed the girl to be. “We will try the NEW songs here,” he said. Night had fallen, and, except for the gas-lamps, the street was empty, and in such darkness that even without his disguise Ford ran no risk of recognition. His plan was not new. It dated from the days of Richard the Lion-hearted. But if the prisoner were alert and intelligent, even though she could make no answer, Ford believed through his effort she would gain courage, would grasp that from the outside a friend was working toward her. All he knew of the prisoner was that she came from Kentucky. Ford fixed his eyes on the houses opposite, and cleared his throat. The man struck the opening chords, and in a high barytone, and in a cockney accent that made even the accompanist grin, Ford lifted his voice. “The sun shines bright on my old Kentucky home,” he sang; “'tis summer, and the darkies are gay.”