"I am afraid he wants to harm Professor Delapine," said Céleste.
"Nonsense," cried Renée, "you surely don't mean to say he wants to injure Delapine?"
"No, no," said Riche, getting alarmed in turn, "she didn't mean that exactly, she merely meant to say—that we must set to work to extinguish the fire if we want to save the house. Now, mademoiselle, you go back to the summer-house with Céleste, and don't stir until I come back, and I promise you no harm shall come to Delapine. Meanwhile I will walk round the house."
With these words he left the two girls, and proceeded to assist the others in tracing the source of the fire.
"I wonder if there can be any truth in Céleste's remark," muttered Riche to himself. "No, no, what Céleste is saying is all nonsense, I will never believe it. I feel convinced that Pierre is in his chambers by this time."
On the day before the séance, Pierre had purchased a quantity of shavings and a large bottle of naphtha together with some phosphorous which he dissolved in it.
"Ah," he said to himself, "this will make a famous blaze, and no one will be able to guess who did it."
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.