I seemed bound to be the prey of a divided duty. As I crossed the street, I asked myself which of the two experiments I had in mind should occupy my attention first. Should I proceed at once with that close study and detailed examination of the house, which I contemplated in my eagerness to establish my theory of a secret passage between it and the one now inhabited by the Misses Quinlan, or should I wait to do this until I had recovered the box, which might hold still greater secrets?

I could not decide, so I resolved to be guided by circumstances. If Mrs. Packard were still out, I did not think I could sit down till I had a complete plan of the house as a start in the inquiry which interested me most.

Mrs. Packard was still out,—so much Nixon deigned to tell me in answer to my question. Whether the fact displeased him or not I could not say, but he was looking very sour and seemed to resent the trouble he had been to in opening the door for me. Should I notice this, even by an attempt to conciliate him? I decided not. A natural manner was best; he was too keen not to notice and give his own interpretation to uncalled for smiles or words which contrasted too strongly with his own marked reticence. I therefore said nothing as he pottered slowly back into his own quarters in the rear, but lingered about down-stairs till I was quite sure he was out of sight and hearing. Then I came back and took up my point of view on the spot where the big hall clock had stood in the days of Mr. Dennison. Later, I made a drawing of this floor as it must have looked at that time. You will find it on the opposite page.

Near the place where I stood [marked A on the plan], had occurred most of the phenomena, which could be located at all. Here the spectral hand had been seen stopping the clock. Here the shape had passed encountered by Mr. Weston’s cook, and just a few steps beyond where the library door opened under the stairs Mr. Searles had seen the flitting figure which had shut his mouth on the subject of his tenants’ universal folly. From the front then toward the back these manifestations had invariably peeped to disappear—where? That was what I was to determine; what I am sure Mayor Packard would wish me to determine if he knew the whole situation as I knew it from his wife’s story and the record I had just read at the agent’s office.

Alas! there were many points of exit from this portion of the hall. The drawing-room opened near; so did Mayor Packard’s study; then there was the kitchen with its various offices, ending as I knew in the cellar stairs. Nearer I could see the door leading into the dining-room and, opening closer yet, the short side hall running down to what had once been the shallow vestibule of a small side entrance, but which, as I had noted many times in passing to and from the dining-room, was now used as a recess or alcove to hold a cabinet of Indian curios. In which of these directions should I carry my inquiry? All looked equally unpromising, unless it was Mayor Packard’s study, and that no one with the exception of Mr. Steele ever entered save by his invitation, not even his wife. I could not hope to cross that threshold, nor did I greatly desire to invade the kitchen, especially while Nixon was there. Should I have to wait till the mayor’s return for the cooperation my task certainly demanded? It looked that way. But before yielding to the discouragement following this thought, I glanced about me again and suddenly remembered, first the creaking board, which had once answered to the so-called spirit’s flight, and secondly the fact which common sense should have suggested before, that if my theory were true and the secret presence, whose coming and going I had been considering, had fled by some secret passage leading to the neighboring house, then by all laws of convenience and natural propriety that passage should open from the side facing the Quinlan domicile, and not from that holding Mayor Packard’s study and the remote drawing-room.

This considerably narrowed my field of inquiry, and made me immediately anxious to find that creaking board which promised to narrow it further yet.

Where should I seek it? In these rear halls, of course, but I hated to be caught pacing them at this hour. Nixon’s step had not roused it or I should have noticed it, for I was, in a way, listening for this very sound. It was not in the direct path then from the front door to the kitchen. Was it on one side or in the space about the dining-room door or where the transverse corridor met the main hall? All these floors were covered in the old-fashioned way with carpet, which would seem to show that no new boards had been laid and that the creaking one should still be here.

I ventured to go as far as the transverse hall,—I was at full liberty to enter the library. But no result followed this experiment; my footsteps had never fallen more noiselessly. Where could the board be? In aimless uncertainty I stepped into the corridor and instantly a creak woke under my foot. I had located the direction in which one of the so-called phantoms had fled. It was down this transverse hall.

Flushed with apparent success, I looked up at the walls on either side of me. They were gray with paint and presented one unbroken surface from base-board to ceiling, save where the two doorways opened, one into the library, the other into the dining-room. Had the flying presence escaped by either of these two rooms? I knew the dining-room well. I had had several opportunities for studying its details. I thought I knew the library; besides, Mr. Searles had been in the library when the shape advanced upon him from the hall,—a fact eliminating that room as a possible source of approach! What then was left? The recess which had once served as an old-time entrance. Ah, that gave promise of something. It projected directly toward where the adjacent walls had once held two doors, between which any sort of mischief might take place. Say that the Misses Quinlan had retained certain keys. What easier than for one of them to enter the outer door, strike a light, open the inner one and flash this light up through the house till steps or voices warned her of an aroused family, when she had only to reclose the inside door, put out the light and escape by the outer one.

But alas! at this point I remembered that this, as well as all other outside doors, had invariably been protected by bolt, and that these bolts had never been found disturbed. Veritably I was busying myself for nothing over this old vestibule. Yet before I left it I gave it another glance; satisfied myself that its walls were solid; in fact, built of brick like the house. This on two sides; the door occupied the third and showed the same unbroken coat of thick, old paint, its surface barely hidden by the cabinet placed at right angles to it. Enough of it, however, remained exposed to view to give me an opportunity of admiring its sturdy panels and its old-fashioned lock. The door was further secured by heavy pivoted bars extending from jamb to jamb. An egg-and-dart molding extended all around the casing, where the inner door had once hung. All solid, all very old-fashioned, but totally unsuggestive of any reasonable solution of the mystery I had vaguely hoped it to explain. Was I mistaken in my theory, and must I look elsewhere for what I still honestly expected to find? Undoubtedly; and with this decision I turned to leave the recess, when a sensation, of too peculiar a nature for me readily to understand it, caused me to stop short, and look down at my feet in an inquiring way and afterward to lift the rug on which I had been standing and take a look at the floor underneath. It was covered with carpet, like the rest of the hall, but this did not disguise the fact that it sloped a trifle toward the outside wall. Had not the idea been preposterous, I should have said that the weight of the cabinet had been too much for it, causing it to sag quite perceptibly at the base-board. But this seemed too improbable to consider. Old as the house was, it was not old enough for its beams to have rolled. Yet the floor was certainly uneven, and, what was stranger yet, had, in sagging, failed to carry the base-board with it. This I could see by peering around the side of the cabinet. Was it an important enough fact to call for explanation? Possibly not; yet when I had taken a short leap up and come down on what was certainly an unstable floor, I decided that I should never be satisfied till I had seen that cabinet removed and the floor under it rigidly examined.

Yet when I came to take a look at this projection from the library window and saw that this floor, like that of the many entrances, was only the height of one step from the ground, I felt the folly into which my inquiring spirit had led me, and would have dismissed the whole subject from my mind if my eyes had not detected at that moment on one of the tables an unusually thin paper-knife. This gave me an idea. Carrying it back with me into the recess, I got down on my knees, and first taking the precaution to toss a little stick-pin of mine under the cabinet to be reached after in case I was detected there by Nixon, I insinuated the cutter between the base-board and the floor and found that I could not only push it in an inch or more before striking the brick, but run it quite freely around from one corner of the recess to the other. This was surely surprising. The exterior of this vestibule must be considerably larger than the interior would denote. What occupied the space between? I went upstairs full of thought. Sometime, and that before long, I would have that cabinet removed.