The diaphragms used in the recorders and reproducers are made of French rolled plate glass, thinner than a sheet of ordinary writing paper. Edward W. Byrn.十九世纪发明进展.
Forty-one distinct inventions relating to the phonograph, covering various forms of recorders, arrangement of parts, making of records, shaving tool, adjustments, etc. 弗兰克·刘易斯·戴尔.爱迪生的生平和发明.