Let us examine, each by each, the possible means of egress. It is clear that the assassins were in the room where Mademoiselle L'Espanaye was found, or at least in the room adjoining, when the party ascended the stairs. It is then only from these two apartments that we have to seek issues. The police have laid bare the floors, the ceilings, and the masonry of the walls, in every direction. No «secret» issues could have escaped their vigilance. But, not trusting to «their» eyes, I examined with my own. There were, then, «no» secret issues. Both doors leading from the rooms into the passage were securely locked, with the keys inside. Let us turn to the chimneys. These, although of ordinary width for some eight or ten feet above the hearths, will not admit, throughout their extent, the body of a large cat. The impossibility of egress, by means already stated, being thus absolute, we are reduced to the windows. Through those of the front room no one could have escaped without notice from the crowd in the street. The murderers «must» have passed, then, through those of the back room. Now, brought to this conclusion in so unequivocal a manner as we are, it is not our part, as reasoners, to reject it on account of apparent impossibilities. It is only left for us to prove that these apparent 'impossibilities' are, in reality, not such.

"There are two windows in the chamber. One of them is unobstructed by furniture, and is wholly visible. The lower portion of the other is hidden from view by the head of the unwieldy bedstead which is thrust close up against it. The former was found securely fastened from within. It resisted the utmost force of those who endeavoured to raise it. A large gimlet-hole had been pierced in its frame to the left, and a very stout nail was found fitted therein, nearly to the head. Upon examining the other window, a similar nail was seen similarly fitted in it; and a vigorous attempt to raise this sash failed also. The police were now entirely satisfied that egress had not been in these directions. And, «therefore,» it was thought a matter of supererogation to withdraw the nails and open the windows.