4to. [iv] 291 pp, lacking the folding plate of the keyboard, scattered foxing, but otherwise very good. Full leather binding, gilt stamped, title plate to spine partially cracked. Palau (21923) notes: "Es traduccion de la obra de Antonio Bemetzrieder y esta muy bien impresa" and the work is indeed beautifully printed, with musical examples throughout and including a charming engraving at the head of the first lesson, featuring three putti playing around a harpsichord. An interesting and unusual keyboard treatise written by a modestly important Spanish mathematician and architect.