you be so kind as to reach behind your chair? What do you find?"

Lawrence lifted up the plain black box and with it he pulled up
the wires which I had so carefully concealed in the cracks of the
floor.

"That," said Kennedy, "is a little instrument called the
microphone. Its chief merit lies in the fact that it will magnify
a sound sixteen hundred times, and carry it to any given point
where you wish to place the receiver. Originally this device was
invented for the aid of the deaf, but I see no reason why it
should not be used to aid the law. One needn't eavesdrop at the
keyhole with this little instrument about. Inside that box there
is nothing but a series of plugs from which wires, much finer
than a thread, are stretched taut. Yet a fly walking near it will
make a noise as loud as a draft-horse. If the microphone is
placed in any part of the room, especially if near the persons
talking--even if they are talking in a whisper--a whisper such as
occurred several times during the evening and particularly while
I was in the next room getting the notes made by my
stenographer--a whisper, I say, is like shouting your guilt from
the housetops.

"You two men, Close and Lawrence, may consider yourselves under
arrest for conspiracy and whatever other indictments will lie
against such creatures as you. The police will be here in a
moment. No, Close, violence won't do now. The doors are
locked--and see, we are four to two."