By focusing on the interior of a speaker's larynx and using infrared, he was able to convert the visible vibrations of the vocal cords into sound of fair quality, but that did not satisfy him. He worked for a while on vibrations picked up from panes of glass in windows and on framed pictures, and he experimented briefly with the diaphragms in speaker systems, intercoms and telephones. He kept on into October without stopping, and finally achieved a device that would give tinny but recognizable sound from any vibrating surface - a wall, a floor, even the speaker's own cheek or forehead.
It is true that all of us are the beneficiaries of crimes committed by our ancestors, and it is true that nothing can be done about that now because the victims are dead and the survivors are innocent. These are good reasons for keeping our mouths shut about the past: but tell me, what are our reasons for silence about atrocities still to come?