“Receiving no reply to his letter, he determined, since Mademoiselle Stangerson would not come to him, that he would go to her. His plan had long been formed. He had made himself master of the plans of the château and the pavilion. So that, one afternoon, while Monsieur and Mademoiselle Stangerson were out for a walk, and while Daddy Jacques was away, he entered the latter by the vestibule window. He was alone, and, being in no hurry, he began examining the furniture. One of the pieces, resembling a safe, had a very small key-hole. That interested him! He had with him the little key with the brass head, and, associating one with the other, he tried the key in the lock. The door opened. He saw nothing but papers. They must be very valuable to have been put away in a safe, and the key to which to be of so much importance. Perhaps a thought of blackmail occurred to him as a useful possibility in helping him in his designs on Mademoiselle Stangerson. He quickly made a parcel of the papers and took it to the lavatory in the vestibule. Between the time of his first examination of the pavilion and the night of the murder of the keeper, Larsan had had time to find out what those papers contained. He could do nothing with them, and they were rather compromising. That night he took them back to the château. Perhaps he hoped that, by returning the papers he might obtain some gratitude from Mademoiselle Stangerson. But whatever may have been his reasons, he took the papers back and so rid himself of an encumbrance.” Rouletabille coughed. It was evident to me that he was embarrassed. He had arrived at a point where he had to keep back his knowledge of Larsan’s true motive. The explanation he had given had evidently been unsatisfactory. Rouletabille was quick enough to note the bad impression he had made, for, turning to the President, he said: “And now we come to the explanation of the Mystery of The Yellow Room!” * * * * * A movement of chairs in the court with a rustling of dresses and an energetic whispering of “Hush!” showed the curiosity that had been aroused. “It seems to me,” said the President, “that the Mystery of The Yellow Room, Monsieur Rouletabille, is wholly explained by your hypothesis. Frédéric Larsan is the explanation. We have merely to substitute him for Monsieur Robert Darzac. Evidently the door of The Yellow Room was open at the time Monsieur Stangerson was alone, and that he allowed the man who was coming out of his daughter’s chamber to pass without arresting him—perhaps at her entreaty to avoid all scandal.” “No, Monsieur President,” protested the young man. “You forget that, stunned by the attack made on her, Mademoiselle Stangerson was not in a condition to have made such an appeal. Nor could she have locked and bolted herself in her room. You must also remember that Monsieur Stangerson has sworn that the door was not open.”