"It is equally certain that if Dollon is still in the Palais, he cannot be in the Dépôt, for the Dépôt has been rigorously searched since his disappearance, and he would most certainly have been found, had he been anywhere about the Dépôt. It is also certain that he is not inside the Palais, because the only means of communication between the Dépôt and the Palais is a single staircase, and it is certain that a corpse could not have been taken that way unperceived.... Then it follows that Jacques Dollon must have got out by the only ways which are in communication with the Dépôt: that is to say, the drains and the chimneys!"

"How could he have got out, or been got out by the drains? As far as I know, there is no system of pipes large enough to allow of the passage of a man through the pipes which join the main sewers; but, as a set-off to that, there is a chimney—the ancient chimney of Marie Antoinette—which communicates with the Dépôt, and the roof I am now on: it must have been by this chimney that the escape was made! Let us see whether this is so or not!"

By the light of his tiny dark lantern Fandor studied afresh the plan of the Palais, and tried to identify the various chimneys about him. He soon picked out the orifice of Marie Antoinette's chimney. After a considering glance at it, he remarked:

"That's odd! Here is the only chimney whose opening is below the ledge of the roofs! It is certain that unless one had been warned, and had examined this roof from some neighbouring building, the orifice of this chimney would not be noticed. If Jacques Dollon passed out by it, no one would notice his exit!"

Our journalist continued his examination, full of excitement. Surely he was on the right track!

"Ah! Ah! Here are stones freshly scraped and scratched!" he cried delightedly. "And this white mark is just the kind of mark which would be made by a cord scraping against the wall! And look what a size this chimney is! It's not only one Jacques Dollon who could pass out by it, but two! But three! A whole army! Ah, ha, I believe I am on the right track! Now for it!"

Fandor bent over and looked down the interior of the chimney; and, at the risk of toppling over, he managed to reach something he saw shining in the darkness of the opening; he drew himself up, radiant:

"By Jove! There are irons fixed in the walls of the chimney to climb up and down by; and, what is more, they bear traces of a recent passage—the rust has been rubbed off here and there!... Yes, it is by this way Dollon has come out!... To whom else could it be an advantage to use this as an exit from the interior of the Palais, on to the roofs?"

Fandor was keen on the scent! Here, indeed, was matter for an article which would bring him into notice—good business for a journalist!

"If Dollon had been alive," reflected Fandor, "it is evident that, once on the roofs, he had a choice of three ways to escape: he could do what I have just done, but the other way about; he could break a skylight, jump into a garret, and lie hidden under the tiles, awaiting the propitious moment when he could gain the corridors below and, mingling with the crowd, slip unobserved into the street; or, he could hide among the roofs, and stay there; or, he could search for an opening—one of those air holes which put the cellars and drains in communication with the exterior.... But I have come to the conclusion that Dollon is dead! Then his corpse could only remain up here; or, it has been put down into some place where nobody goes. The garrets of the Palais are so incessantly visited by the clerks and registrars that no corpse could remain undiscovered in any of them. Therefore, either Jacques Dollon's corpse is somewhere on the roofs of the Palais, or there is some sort of communication between the roofs and the drains—it is obvious!"