Science Art: Sound Vibrations, 1892

from Sound and Music: https://archive.org/stream/soundmusicx00zahm#page/410/mode/2up Click to embiggen

Seeing what we hear, in 1892. Did they have oscilloscopes in 1892? I don’t think they did. But they could visualize this.

At any rate, I found this via Nemfrog in Sound and Music by John Augustine Zahm.