It was the dark centre of Camus’ life, the depository, without doubt, of his secrets. What he would find there in the way of written or other evidence, Lavenne did not know; of how he would prosecute his search, he had no definite plan; yet he knew that here was the only place where Justice might rest her lever as on a fulcrum, and with one swift movement send the Poisoner crashing to the pit that awaited him. As he lay in the darkness revolving these matters in his mind, he heard the great clock of the Hôtel chiming the hour of eleven. He determined to wait till midnight. Jumeau had told him that Camus had gone to the Hôtel Dubarry and would not be home, most likely, till the small hours, if then. Lavenne felt that he had the whole night before him, unconscious of the fact that Camus’ hour of return that night was not at all to be counted on, simply for the reason that Camus, when Camille Fontrailles left the party, had become restless, and though he had taken his place at the card-table, showed such absence of mind that Luck, who hates a cold lover, declared herself dead against him. Meanwhile Monsieur Brujon retired to rest, but not before sending a special messenger to Monsieur Gaston Le Roux with a note, enclosing the testimonial, and an inquiry as to whether the man mentioned in it was to be trusted. M. Le Roux’s reply consisted of only one word, “Absolutely.” CHAPTER VI THE LABORATORY At twelve o’clock, Lavenne, slipping from the bed, felt in his pockets to make sure that the _crochet_, the tinder-box and steel and the three special candles which he had brought with him, short and thick like modern night-lights, were to hand. Then he opened his door. The passage was in black darkness, yet he felt sure of finding his way. He had noted the length of the passage, the position of the doors, and the position of the staircase leading to the upper floor; he had counted the number of steps in the stairs, the form of the landing to which they led was mapped in his mind, and also the point in the landing from which opened the passage leading to the dining-room corridor and to the laboratory of Camus. He closed the door of the bedroom carefully, and groping his way, passed down the passage to the stairs. The stairs creaked under his foot, some stairways seem to creak the louder the more softly they are trodden on. Lavenne knew this idiosyncrasy and went boldly, reached the landing, found the passage to the dining-room corridor, and in a moment more was spreading his fingers on the door of Camus’ private room in search of the key-hole. Then, taking the _crochet_ from his pocket, he inserted it in the lock.