Kennedy
seemed engrossed in it while the rest of us fidgeted at the delay.
"Can you get me a couple of old telephone instruments?" he asked at
length, turning to us and addressing the St. Cenis detective.
The detective nodded and disappeared down the hall. A few minutes
later he deposited the instruments on a table. Where he got them
I do not know, but I suspect he simply lifted them from vacant rooms.
"Now some Number 30 copper wire and a couple of dry cells," ordered
Kennedy, falling to work immediately on the telephones. The
detective despatched a bellboy down to the basement to get the
wire from the house electrician.
Kennedy removed the transmitters of the telephones, and taking the
carbon capsules from them placed the capsules on the table carefully.
Then he lifted down the etching from the wall and laid it flat on
its face before us. Quickly he removed the back of the picture.
Pressing the transmitter fronts with the carbon capsules against
the paper and the glass on the picture he mounted them so that the
paper and glass acted as a large diaphragm to collect all the sounds
in the room.
"The size of this glass diaphragm," he explained as we gathered
around in intense interest at what he was doing, "will produce a
strikingly sensitive microphone action and the merest whisper will
be reproduced with startling distinctness.
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