On arriving at the house of Dr. Villebois some time after dinner on the evening of the séance, he availed himself of a favourable opportunity, at a moment when the servant was not looking, to deposit a small black bag in a corner of the hall. Just at the beginning of the séance, as will be remembered, he slipped out of the room and recovering his bag from its hiding place, went cautiously upstairs to Riche's bedroom, taking extra precautions that no one should see him enter. Quickly making a small heap of the shavings under the bed, he soaked them with the mixture of naptha and phosphorous. Then making sure that everything was in order for his dastardly purpose he left the room as stealthily as he had entered it, noiselessly locking the door behind him, and placing the key in his pocket. "Now," he muttered, "I must get back to the 'spiritualists' and watch their movements from my place of vantage, and then mon brave Delapine, we shall see." Pierre returned to the room adjoining the séance room, which opened into the conservatory, and taking up a position behind a curtain from where he could see what went on without being observed, he cautiously opened the little phial containing some of the liquid he had stolen from Paul's laboratory on the evening of his visit to the analyst, and proceeded to fill a small hypodermic syringe with the fluid. "Confound that fire," he muttered. "It seems an uncommonly long time in starting. I'll sneak back and see if anything has gone wrong." No sooner had he opened the door of the dining-room, when he perceived the strong odour of burning wood and naptha, and looking up the stairs he observed a bluish cloud of smoke slowly making its way along the ceiling, and spreading down the stairs. "That seems to be all right," he said to himself, as he returned to his hiding-place. In about five minutes' time the smoke began slowly to penetrate the room and make its way into the séance chamber. "Keep calm, keep calm," he said to himself, as he heard a commotion among the guests in the adjoining room. Peeping through the keyhole, Pierre saw the guests hurriedly rise up and rush out through the conservatory into the garden. As soon as he had ascertained that the last person had left the room, he cautiously opened the door and crept into the séance room. He first adjusted the blinds of the conservatory window and door, so that no light could penetrate, and then turned up the lights sufficiently high to observe the professor in the cabinet. There he was, clear enough, sleeping as calmly as an infant.