Codex Harmonicus V — De Unda Aeris

Folio V of the Codex Harmonicus, a recovered-manuscript-style plate on sound as a wave in air — ripples on water as a model for sound, the speed of an echo, the dissected human voice, and sympathetic resonance between bodies.

What's inside

• Rings on water as a model for sound — how two voices pass through each other unmixed, with a diagram of two overlapping ripples
• Measuring a valley by its echo, and the speed of sound worked out from a shout, a plumb-line and a distant gun
• How sound travels differently through air, water, wood and iron, with a table of speeds and ratios
• The bending of sound by wind and by warm and cold air, and why a listener hears best at dawn, downwind, over water
• The human voice dissected — the throat, the mouth's two chambers, and a table of vowels by pitch
• Sympathetic resonance between bodies, and a table of how the delay of an echo tells the size of the room that returns it