them. In an instant Craig had entered the cabinet, and in a dark
corner on the floor he deposited the mechanism he had brought
from the laboratory. Then he resumed his seat, shutting the box
in which he had brought the mechanism, so that it would not
appear that he had left anything about the room.

Artfully he led the conversation along lines that interested the
old man until he seemed to forget the hour. Not so, Craig. He
knew it was nearing half-past twelve. The more they talked the
more uncanny did this house and room of spirits seem to me. In
fact, I was rapidly reaching the point where I could have sworn
that once or twice something incorporeal brushed by me. I know
now that it was purely imagination, but it shows what tricks the
imagination can play on us.

Rap! rap! rap! rap! rap!

Five times came a curiously hollow noise from the cabinet. If it
had been possible I should certainly have fled, it was so sudden
and unexpected. The hall clock downstairs struck the half-hour in
those chimes written by Handel for St. Paul's.

Craig leaned over to me and whispered hoarsely, "Keep perfectly
still--don't move a hand or foot."

The old man seemed utterly to have forgotten us. "Is that you,
John?" he asked expectantly.

Rap! rap! rap! came the reply.