Image: Dictaphone cylinder machine

Description: Photo of a Dictaphone wax cylinder dictation machine, made by Columbia Graphophone Company in the 1920s. The user pressed a button on the mouthpiece, which started the cylinder turning, and spoke into it. The sound travelled down the tube and vibrated a membrane attached to a needle cutting a groove in the wax surface of the cylinder. The needle inscribes a record of the sound vibrations into the cylinder. To replay it, the mouthpiece was detached and replaced with a pair of 'stethoscope' type earphones. Each wax cylinder can hold about 1200-1500 words, and can be reused 100-120 times by erasing it with a machine that 'shaves' the surface off. Alterations: removed caption, erased noise in white areas, increased brightness.
Title: Dictaphone cylinder machine
Credit: Downloaded 2008-1-12 from Clarence Charles Smith (1922) The Expert Typist, MacMillan Co., New York, USA, p.123, fig.37 on Google Books. The photo is credited (p.122) to the Columbia Phonograph Co.
Author: Columbia Phonograph Co.
Permission: Public domain - published in USA before 1923.
Usage Terms: Public domain
License: Public domain
Attribution Required?: No