"The graphic method of studying sounds, which fairly meets even the exacting demands of physicists, and is largely used by them may be briefly explained thus: Suppose the smoked plate [shown] to be a sheet of smoked paper fastened around a cylinder that is mounted that, when it is turned by a crank, the screw cut upon the axis moves the cylinder endwise as shown. Such and instrument is called a vibroscope." -Avery 1895

Graphic Method of Studying Sounds Using A Vibroscope

"The graphic method of studying sounds, which fairly meets even the exacting demands of physicists,…