new pin, were there any traces of a man's footmarks. Since they have been found near this window outside, he must have made his way through the ceiling of The Yellow Room into the attic, then cut his way through the roof and dropped to the ground outside the vestibule window. But—there's no hole, neither in the ceiling of The Yellow Room nor in the roof of my attic—that's absolutely certain! So you see we know nothing—nothing! And nothing will ever be known! It's a mystery of the devil's own making."
Rouletabille went down upon his knees again almost in front of a small lavatory at the back of the vestibule. In that position he remained for about a minute.
"Well?" I asked him when he got up.
"Oh! nothing very important,—a drop of blood," he replied, turning towards Daddy Jacques as he spoke. "While you were washing the laboratory and this vestibule, was the vestibule window open?" he asked.
"No, Monsieur, it was closed; but after I had done washing the floor, I lit some charcoal for Monsieur in the laboratory furnace, and, as I lit it with old newspapers, it smoked, so I opened both the windows in the laboratory and this one, to make a current of air; then I shut those in the laboratory and left this one open when I went out. When I returned to the pavilion, this window had been closed and Monsieur and Mademoiselle were already at work in the laboratory."
"Monsieur or Mademoiselle Stangerson had, no doubt, shut it?"
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