"Step-daughter," he said, with a wink. "By my first wife. The girl in the way then. Much more in the way now. Why? Her mother's dead, and I'm married again. Conundrum. What relation is she to my second wife? Work it out. Name, Maria. A perfect encumbrance. Dumb from her birth. And silly. Horrible nuisance. No vice in her. Not dangerous in the least. Therefore, friendly patient. No restraint or punishment. To be allowed to go about the house and grounds. Do as she likes. Must sleep in room by herself. Will give no trouble. Quarter paid in advance. Make her happy, and she shall remain for years. Must be kindly treated. Will programme do?" "It is excellently arranged." "I go down as Mr. Nettlefold, The Elms, Ealing. Cousin of mine lives there. Should letters addressed Nettlefold arrive, will forward them on to me wherever I am. As I say, go down as Mr. Nettlefold. Leave Sheldon as such. Return to Sheldon as another man. To watch over Sophy, otherwise Maria. Got danger signals ready." He produced a number of small pellets, some blue, some white, weighted, and attached to thin cords. "Sophy," he continued, "otherwise Maria, ties these to underclothing. Stays. String of petticoat. Anything. Detaches one when required. I'll instruct her. Every day one thrown over wall. None thrown, go in and see her. Quite safe. Will she remain long?" I answered that I thought she would be able to get hold of the desk in less than a week, and that under no circumstances should she remain longer than a fortnight. If she could not accomplish her task in that time it would be useless to keep her there. We continued talking about the arrangements till half-past one, when my faithful and punctual Sophy made her appearance. She looked the picture of neatness, and her eyes beamed when I expressed approval of her attire. Bob gazed upon her with satisfaction. "She'll do," he said. "You keep quiet. I'll take her in hand." I left it to him to explain matters and to teach her her lesson. He could have had no apter pupil; in less than half an hour she was proficient. "We start, the three of us," said Bob, "at three o'clock. Not for Sheldon. Four miles from there is a large village, Nutford. We put up there. Arrive six-twenty. Have dinner. Dark night. Walk to Sheldon. Reconnoitre. Show you the wall, where you can get over. If you want to. Show you where to throw pellets. Four o'clock every afternoon. Convenient time. Dr. Peterssen probably away. Feel all right?" "As right as a trivet," said Sophy. "You're a girl--after my own heart. Have something to eat before we start. Tuck away." At three o'clock we were in the train which was to convey us to our destination. CHAPTER XLVIII. SOPHY ENTERS DR. PETERSSEN'S ESTABLISHMENT AS A FRIENDLY PATIENT.