Italian Harpsichord-Building in the 16th and 17th Centuries · John D. Shortridge — chapter 4 of 4 · ~8 words · public domain
Marin Mersenne, Harmonie Universelle, Paris, 1636, p. 101.
Italian Harpsichord-Building in the 16th and 17th Centuries · The Wunder Library — complete classics, free to read, with narration.