Greatly sobered, I restored the paper to its place in the box, slipped on the string and prepared to leave the cellar with it.  Then I remembered the brick on the floor and the open hole where it had been, and afterward the something which had fallen over within and what this space might mean in a seemingly solid wall.

More excited now even than I had been at any time before, I thrust my hand in again and tried to sound the depth of this unexpected far-reaching hole; but the size of my arm stood in the way of my experiment, and, drawing out my hand, I looked about for a stick and finding one, plunged that in.  To my surprise and growing satisfaction it went in its full length—­about three feet.  There was a cavity on the other side of this wall of very sizable dimensions.  Had I struck the suspected passage?  I had great hope of it.  Nothing else would account for so large a space on the other side of a wall which gave every indication of being one with the foundation.  Catching up my stick I made a rude estimate of its location, after which I replaced the brick, put out the gas, and caught up Bess’ box.  Trembling, and more frightened now than at my descent at my own footfall and tremulous pursuing shadow, I went up-stairs.

As I passed the corridor leading to the converted vestibule which had so excited my interest in the afternoon, I paused and made a hurried calculation.  If the stick had been three feet long, as I judged, and my stride was thirty inches, then the place of that hole in the wall below was directly in a line with where I now stood,—­in other words, under the vestibule floor, as I had already, suspected.

How was I to verify this without disturbing Mrs. Packard?  That was a question to sleep on.  But it took me a long time to get to sleep.

CHAPTER XIV

I SEEK HELP

A bad night, a very bad night, but for all that I was down early the next morning.  Bess must have her box and I a breath of fresh air before breakfast, to freshen me up a bit and clear my mind for the decisive act, since my broken rest had failed to refresh me.

As I reached the parlor floor Nixon came out of the reception-room.

“Oh, Miss!” he exclaimed, “going out?” surprised, doubtless, to see me in my hat and jacket.

“A few steps,” I answered, and then stopped, not a little disturbed; for in moving to open the door he had discovered that the key was not in it and was showing his amazement somewhat conspicuously.

“Mrs. Packard took the key up to her room,” I explained, thinking that some sort of explanation was in order.  “She is nervous, you know, and probably felt safer with it there.”

The slow shake of his head had a tinge of self-reproach in it.

“I was sorry to go out,” he muttered.  “I was very sorry to go out,”—­but the look which he turned upon me the next minute was of a very different sort.  “I don’t see how you can go out yet,” said he, “unless you go by the back way.  That leads into Stanton Street; but perhaps you had just as lief go into Stanton Street.”