Still, upon close examination, it was evident that it was not cemented in.

Taking out a penknife from her pocket, she found that the joint was too close even to allow this to be inserted for any distance.

There was no keyhole or any other visible means of opening it, and she searched the walls in vain for any hidden spring.
For a whole week she continued the search, but without the slightest success, and at last began almost to despair; for at the end of that time she was convinced that she had passed her fingers again and again over every square inch of the floor and walls within her reach.
Completely worn out with her sleepless nights, she determined to take a little rest, and to abstain altogether for a few nights from the search.

On the third night, however, an idea suddenly occurred to her.
She rose at once, dressed herself, and was about to go downstairs, when she thought that she heard a noise below.

She returned at once to her room, hid away her hat and coat, and again went to the top of the stairs and listened.
Yes, she had not been mistaken; she distinctly heard sounds below, and, she thought, the murmur of men's voices.