Illustration of Saint John the Evangelist sitting on a rock with a writing tablet in his lap. He is writing on the tablet. An eagle, often associated with John, is perched on the ground next to him. A tall staff with a cross at the top is leaning against a rock in the background.

Saint John the Evangelist Writing

Illustration of Saint John the Evangelist sitting on a rock with a writing tablet in his lap. He is…

An instrument for registering the vibrations of a sounding body.

Phonautograph

An instrument for registering the vibrations of a sounding body.

A form of the phonautograph invented by Thomas A. Edison, by mean which sounds are made to produce on a register permanent tracings, each having an individual character corresponding to the sound it produces.

Phonograph

A form of the phonautograph invented by Thomas A. Edison, by mean which sounds are made to produce on…