Reaching home he passed into his study, and, seating himself at his writing-table, pulled a sheet of note-paper towards him and began to sketch, as well as he could remember it, the box he had seen. Then he leant back in his chair and closed his eyes. "I have cracked a good many hard nuts in my time," he said reflectively, "but never one that seemed so difficult at first sight as this. As far as I see at present, the case stands as follows: the box will be brought from the bank where it usually reposes to Wiltshire House on the morning of the dance. I shall be allowed to have possession of it, without the stones of course, for a period possibly extending from eleven o’clock in the morning to four or five, at any rate not later than seven, in the evening. After the ball the necklace will be returned to it, when it will be locked up in the safe, over which the butler and a footman will mount guard. "To get into the room during the night is not only too risky, but physically out of the question; while to rob Her Grace of her treasure during the progress of the dance would be equally impossible. The Duke fetches the casket and takes it back to the bank himself, so that to all intents and purposes I am almost as far off the solution as ever." Half-an-hour went by and found him still seated at his desk, staring at the drawing on the paper, then an hour. The traffic of the streets rolled past the house unheeded. Finally Jowur Singh announced his carriage, and, feeling that an idea might come to him with a change of scene, he set off for a drive in the Park. By this time his elegant mail phaeton, with its magnificent horses and Indian servant on the seat behind, was as well known as Her Majesty’s state equipage, and attracted almost as much attention. To-day, however, the fashionable world noticed that Simon Carne looked pre-occupied. He was still working out his problem, but so far without much success. Suddenly something, no one will ever be able to say what, put an idea into his head. The notion was no sooner born in his brain than he left the Park and drove quickly home. Ten minutes had scarcely elapsed before he was back in his study again, and had ordered that Wajib Baksh should be sent to him. When the man he wanted put in an appearance, Carne handed him the paper upon which he had made the drawing of the jewel case. "Look at that," he said, "and tell me what thou seest there." "I see a box," answered the man, who by this time was well accustomed to his master’s ways.