Codex Harmonicus II — De Motu Chordae

Folio II of the Codex Harmonicus, a recovered-manuscript-style plate on tension, weight and the measure of time — the three causes of pitch, the swinging pendulum, and a table of tempo markings against a beating thread.

What's inside

• The three causes of pitch — length, pull and thickness — set out as a proportion, with a diagram of the loaded canon
• The plumb-line as a measure of tempo, with the timing formula for one beat of a swinging weight
• A table of seven tempo markings, from grave to presto, each given in beats, thread length and braccia
• A table of weights hung from one string and the consonant intervals each produces
• Notes on stringing a lute of six courses so that every course pulls alike
• A short study of how weather — damp, cold and dry — untunes an instrument through the day