Pallophotophone
an apparatus for recording and reproducing sounds photographically. The human voice or other sound is made to cause the oscillation of a delicate mirror and in this way to affect a beam of light reflected from the mirror to a photographic film in continuous motion. The sound is reproduced by moving the developed film in front of a delicate electrical device whose energy is affected by the intensity of the light falling upon it. The electrical current with these impressed variations is in turn transformed to sound as in ordinary telephony or as in radio with loud-speaking devices. The pallophotophone has already been used to make records for broadcasting from radio stations. Its possible applications in the recording and reproducing of long speeches, lectures, etc., are obvious, while it also makes possible the simultaneous recording of pictures and sounds on the same photographic film, thus answering the main problem of the talking motion picture.