until I reached the fourth story, where I dashed
through an open doorway, slammed behind me an iron door, which shut with
a spring, and fell gasping upon the floor.

"In less than a minute I was aware, by a slight rattling of the
grate-hinges, that something was pushing against the door; but I did not
move. I knew that I was safe. The room in which I lay was a prison
dungeon, and in it, in the olden times, it is said, men had been left to
perish. Escape or communication with the outer world was impossible. A
little light and air came through a narrow slit in the wall, and the
door could not be forced.

"I knew that the invisible dog, or whatever it was, could not get in
unless the door was open. I had frequently noticed that when he entered
a room it was through an open door, and I sometimes knew of his approach
by seeing an unlatched door open without visible cause; so, feeling
secure for the present, I lay and gasped and panted.

"After the lapse of a few hours, however, I was seized by a new terror.
How was I ever to get out of this horrible dungeon? Even if I made up my
mind to face the dog, trusting that he had recovered from his momentary
anger, I had no means of opening the door, and as to making any one hear
me I knew that was impossible.

"I had no hope that my servants would seek me here. I had not seen any
one when I ran into the tower, and if they should discover that I was in
this dungeon, how could they open the door? The key was in my father's
possession. He had taken it to Vienna to exhibit it as a curiosity to
some of his mechanical friends. He believed that there was not such
another key in the world. I was in the habit of making long absences
from the castle, and if I should be looked for I believed that the tower
would be the last place visited.

"Night came on; the little light in the room vanished, and, hungry,
thirsty, and almost hopeless, I fell asleep.

"During the night there was a most dreadful storm. The thunder roared,
the lightning flashed through the slit in the wall, and the wind blew
with such terrific violence that the tower shook and trembled. After a
time I heard a tremendous crash as of falling walls, and then another,
and now I felt the wind blowing into my prison.

"There was no further sleep for me. Trembling with a fearful
apprehension of what might happen next, I cowered against the wall until
the day broke, and then I perceived that in front of me was a great hole
in th