I had hoped to find him at the station at Epinay; but he was not there. However, a cab was waiting for me and I was soon at the Glandier. Nobody was at the gate, and it was only on the threshold of the château that I met the young man. He saluted me with a friendly gesture and threw his arms about me, inquiring warmly as to the state of my health. When we were in the little sitting-room of which I have spoken, Rouletabille made me sit down. “It’s going badly,” he said. “What’s going badly?” I asked. “Everything.” He came nearer to me and whispered: “Frédéric Larsan is working with might and main against Darzac.” This did not astonish me. I had seen the poor show Mademoiselle Stangerson’s fiancé had made at the time of the examination of the footprints. However, I immediately asked:— “What about that cane?” “It is still in the hands of Frédéric Larsan. He never lets go of it.” “But doesn’t it prove the alibi for Monsieur Darzac?” “Not at all. Gently questioned by me, Darzac denied having, on that evening, or on any other, purchased a cane at Cassette’s. However,” said Rouletabille, “I’ll not swear to anything; Monsieur Darzac has such strange fits of silence that one does not know exactly what to think of what he says.” “To Frédéric Larsan this cane must mean a piece of very damaging evidence. But in what way? The time when it was bought shows it could not have been in the murderer’s possession.” “The time doesn’t worry Larsan. He is not obliged to adopt my theory which assumes that the murderer got into The Yellow Room between five and six o’clock. But there’s nothing to prevent him assuming that the murderer got in between ten and eleven o’clock at night? At that hour Monsieur and Mademoiselle Stangerson, assisted by Daddy Jacques, were engaged in making an interesting chemical experiment in the part of the laboratory taken up by the furnaces. Larsan says, unlikely as that may seem, that the murderer may have slipped behind them. He has already got the examining magistrate to listen to him. When one looks closely into it, the reasoning is absurd, seeing that the ‘intimate’—if there is one—must have known that the professor would shortly leave the pavilion, and that the ‘friend’ had only to put off operating till after the professor’s departure. Why should he have risked crossing the laboratory while the professor was in it? And then, when he had got into The Yellow Room?—