Thus it came to pass that on a certain night in August, about two in the morning, Paul Coquenil found himself alone in the baron’s spacious, silent library before a massive safe.  The opening of this safe is another matter that need not be gone into—­a desperate case justifies desperate risk, and an experienced burglar chaser naturally becomes a bit of a burglar himself; at any rate, the safe swung open in due course, without accident or interference, and the detective stood before it.

All this Coquenil had done on a chance, without positive knowledge, save for the assurance of the black-whiskered valet that the baron wrote frequently in a diary which he kept locked in the safe.  Whether this was true, and, if so, whether the baron had been mad enough to put down with his own hand a record of his own wickedness, were matters of pure conjecture.  Coquenil was convinced that this journal would contain what he wanted; he did not believe that a man like De Heidelmann-Bruck would keep a diary simply to fill in with insipidities.  If he kept it at all, it would be because it pleased him to analyze, fearlessly, his own extraordinary doings, good or bad.  The very fact that the baron was different from ordinary men, a law unto himself, made it likely that he would disregard what ordinary men would call prudence in a matter like this; there is no such word as imprudence for one who is practically all-powerful, and, if it tickled the baron’s fancy to keep a journal of crime, it was tolerably certain he would keep it.

The event proved that he did keep it.  On one of the shelves of the safe, among valuable papers and securities, the detective found a thick book bound in black leather and fastened with heavy gold clasps.  It was the diary.

With a thrill of triumph, Coquenil seized upon the volume, then, closing the safe carefully, without touching anything else, he returned to his room in the stable.  His purpose was accomplished, and now he had only one thought—­to leave the hotel as quickly as possible; it would be a matter of a few moments to pack his modest belongings, then he could rouse the doorkeeper and be off with his bag and the precious record.

As he started to act on this decision, however, and steal softly down to the courtyard, the detective paused and looked at his watch.  It was not yet three o’clock, and M. Paul, in the real burglar spirit, reflected that his departure with a bag, at this unseasonable hour, might arouse the doorkeeper’s suspicion; whereas, if he waited until half past five, the gate would be open and he could go out unnoticed.  So he decided to wait.  After all, there was no danger, the baron was away from Paris, and no one would enter the library before seven or eight.