Pronunciation GB: ˈkaɪməɡrɑːf, GA: ˈkaɪməɡræf

An early instrument for measuring changes in bodily function through time. It was used in early research into speech acoustics to record speech pressure variation. It consisted of a revolving drum covered usually in smoked paper. The signal to be recorded was transduced into mechanical movement of a stylus, which scraped off the smoke layer as it moved at right angles to the drum’s direction of rotation.