"A moment ago, Mr. Kennedy, I saw you and Mr. Jameson glancing up
at the ceiling. Sound-proof as this room is, or as I believe it to
be, I--I hear voices, voices from--not through, you understand,
but from--that very ceiling. I do not hear them now. It is only at
certain times when I am alone. They repeat the words in some of
these letters--'You must not take up those bonds. You must not
endanger the peace of the world. You will never live to get the
interest.' Over and over I have heard such sentences spoken in
this very room. I have rushed out and up the corridor. There has
been no one there. I have locked the steel door. Still I have
heard the voices. And it is absolutely impossible that a human
being could get close enough to say them without my knowing and
finding out where he is."

Kennedy betrayed by not so much as the motion of a muscle even a
shade of a doubt of Brixton's incredible story. Whether because he
believed it or because he was diplomatic, Craig took the thing at
its face value. He moved a blotter so that he could stand on the
top of Brixton's desk in the centre of the room. Then he
unfastened and took down the glass hemisphere over the light.

"It is an Osram lamp of about a hundred candlepower, I should
judge," he observed.

Apparently he had satisfied himself that there was nothing
concealed in the light itself. Laboriously, with such assistance
as the memory of Mr. Brixton could give, he began tracing out the
course of both the electric light and telephone wires that led
down into the den.