were probably hunting outside the house, dredging the creek, or beating the woodland.  I knew that another hour or two would find me unconscious, and with my inability to cry out would go my only chance of rescue.  It was the combination of bad air and heat, probably, for some inadequate ventilation was coming through the pipes.  I tried to retain my consciousness by walking the length of the room and back, over and over, but I had not the strength to keep it up, so I sat down on the table again, my back against the wall.

The house was very still.  Once my straining ears seemed to catch a footfall beneath me, possibly in my own room.  I groped for the chair from the table, and pounded with it frantically on the floor.  But nothing happened:  I realized bitterly that if the sound was heard at all, no doubt it was classed with the other rappings that had so alarmed us recently.

It was impossible to judge the flight of time.  I measured five minutes by counting my pulse, allowing seventy-two beats to the minute.  But it took eternities, and toward the last I found it hard to count; my head was confused.

And then—­I heard sounds from below me, in the house.  There was a peculiar throbbing, vibrating noise that I felt rather than heard, much like the pulsing beat of fire engines in the city.  For one awful moment I thought the house was on fire, and every drop of blood in my body gathered around my heart; then I knew.  It was the engine of the automobile, and Halsey had come back.  Hope sprang up afresh.  Halsey’s clear head and Gertrude’s intuition might do what Liddy’s hysteria and three detectives had failed in.

After a time I thought I had been right.  There was certainly something going on down below; doors were slamming, people were hurrying through the halls, and certain high notes of excited voices penetrated to me shrilly.  I hoped they were coming closer, but after a time the sounds died away below, and I was left to the silence and heat, to the weight of the darkness, to the oppression of walls that seemed to close in on me and stifle me.

The first warning I had was a stealthy fumbling at the lock of the mantel-door.  With my mouth open to scream, I stopped.  Perhaps the situation had rendered me acute, perhaps it was instinctive.  Whatever it was, I sat without moving, and some one outside, in absolute stillness, ran his fingers over the carving of the mantel and—­found the panel.

Now the sounds below redoubled:  from the clatter and jarring I knew that several people were running up the stairs, and as the sounds approached, I could even hear what they said.

“Watch the end staircases!” Jamieson was shouting.  “Damnation—­ there’s no light here!” And then a second later.  “All together now.  One—­two—­three—­”