fastened from within. It resisted the utmost force of those who endeavored 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 bad not been in these directions. And, therefore, it was thought a matter of supererogation to withdraw the nails and open the windows.

"My own examination was somewhat more particular, and was so for the reason I have just given—because here it was, I know, that all apparent impossibilities must be proved to be not such in reality.

"I proceeded to think thus—a posteriori. The murderers did escape from one of these windows. This being so, they could not have refastened the sashes from the inside, as they were found fastened—the consideration which puts a stop, through its obviousness, to the scrutiny of the police in this quarter. Yet the sashes were fastened. They must, then, have the power of fastening themselves. There was no escape from this conclusion. I stepped to the unobstructed casement, withdraw the nail with some difficulty, and attempted to raise the sash. It resisted all my efforts, as I had anticipated. A concealed spring must, I now knew, exist; and this corroboration of my idea convinced me that my premises, at least, were correct, however mysterious still appeared the circumstances attending the nail. A careful search soon brought to light the hidden spring. I pressed it, and, satisfied with the discovery, forbore to upraise the sash.

"I now replaced the nail and regarded it attentively. A person passing out through this window might have reclosed it, and the spring would have caught: but the