Knowing she was as yet unseen, Mrs.Conway entered the library and closed the door behind her.

Then she hurried to the fireplace, touched the two springs, pulled the bookcase open and entered the secret chamber, and closed the bookcase behind her.
She had often examined the lock, thinking that the secret spring of the closet might be concealed here.

It was a large old-fashioned one, and moved two bolts, one at the top of the door and one at the bottom.
These she had already discovered could be easily opened from the inside.

She imagined that Miss Penfold was merely going round the house to see that all was secure, and she had, contrary to her practice, taken the key from the door of the library in order that Miss Penfold might enter it if she chose.

But the thought now flashed across her that possibly she might intend to open the secret room; and to prevent this she now thrust the barrel of the pistol she carried in between the back of the bolt and the piece of iron against which it shot, so that the action of the springs could not throw it out of its place.
Breathlessly she listened.