the resemblance to a perfect nail was complete—the fissure was invisible. Pressing the spring, I gently raised the sash for a few inches; the head went up with it, remaining firm in its bed. I closed the window, and the semblance of the whole nail was again perfect.
"The riddle, so far, was now unriddled. The assassin had escaped through the window which looked upon the bed. Dropping of its own accord upon his exit (or perhaps purposely closed), it had become fastened by the spring; and it was the retention of this spring which had been mistaken by the police for that of the nail,—further inquiry being thus considered unnecessary.
"The next question is that of the mode of descent. Upon this point I had been satisfied in my walk with you around the building. About five feet and a half from the casement in question there runs a lightning-rod. From this rod it would have been impossible for any one to reach the window itself, to say nothing of entering it. I observed, however, that the shutters of the fourth story were of the peculiar kind called by Parisian carpenters ferrades—a kind rarely employed at the present day, but frequently seen upon very old mansions at Lyons and Bordeaux. They are in the form of an ordinary door (a single, not a folding door), except that the lower half is latticed or worked in open trellis, thus affording an excellent hold for the hands. In the present instance these shutters are fully three feet and a half broad. When we saw them from the rear of the house they were both about half open—that is to say, they stood off at right angles from the wall, It is probable that the police, as well as myself, examined the back of the tenement; but if so, in looking at these ferrades in the line of their breadth (as they must have done), they did not perceive this great breadth itself, or, at all events, failed to take it into due
