hrough the flooring and might be somewhere over my head.

But my candle was inadequate for more than the most superficial
examination of the ceiling, which presented so far as I could see an
unbroken surface. I turned my attention, therefore, to the floor. It was
when I was turning the rug back that I recognized the natural and not
supernatural origin of the sound which had so startled me. It had been
the soft movement of the carpet across the floor boards.

Some one, then, had been there before me--some one who knew what I knew,
had reasoned as I reasoned. Some one who, in all probability, still
lurked on the upper floor.

Obeying an impulse, I stood erect and called out sharply, "Sperry!" I
said. "Sperry!"

There was no answer. I tried again, calling Herbert. But only my own
voice came back to me, and the whistling of the wind through the window
I had opened.

My fears, never long in abeyance that night, roused again. I had
instantly a conviction that some human figure, sinister and dangerous,
was lurking in the shadows of that empty floor, and I remember backing
away from the door and standing in the center of the room, prepared for
some stealthy, murderous assault. When none came I looked about for a
weapon, and finally took the only thing in sight, a coal-tongs from the
fireplace. Armed with that, I made a cursory round of the near-by rooms
but there was no one hiding in them.

I went back to the rug and examined the floor beneath it. I was right.
Some one had been there before me. Bits of splintered wood lay about.
The second bullet had been fired, had buried itself in the flooring, and
had, some five minutes before, been dug out.

VII

The extraordinary thing about the Arthur Wells story was not his
killing. For killing it was. It was the way it was solved.

Here was a young woman, Miss Jeremy, who had not known young Wells, had
not known his wife, had, until that first meeting at Mrs. Dane's, never
met any member of the Neighborhood Club. Yet, but for her, Arthur Wells
would have gone to his grave bearing the stigma of moral cowardice, of
suicide.

The solution, when it came, was amazing, but remarkably simple. Like
most mysteries. I have in my own house, for instance, an example of a
great mystery, founded on mere absentmindedness.

This is what my wife terms the mystery of the fire-tongs.

I had left the Wells house as soon as I had made the discovery in the
night nursery. I carried the