Good morning to all of you.
I've been listening to a compact disc featuring mostly lesser-known
madrigals and three harpsichord works.
The harpsichord seemed quite special to me, and it special it is: It
is a model that was built to be able to play late renaissance or early
baroque music in natural temperament as well as in equal temperament.
Each octave needs 19 notes to reach this aim, they write in the
introductory notes.
But is it possible to play every single tones in natural temperament,
with 'only' nineteen notes? Does anyone know about this?
Have a nice day.
C. Songeur.

Here is a note on this instrument:
The Cembalo universale was constructed in 1979 by Keith Hill in
accordance with descriptions contained in Michael Praetorius's
Syntagma musicum II (1619). This harpsichord has a compass of four
octaves, each of which is equipped with seven additional sharp keys to
form sub-semitones. The instrument therefore has 19 keys per octave
and allows chromatic repertoire of the late Renaissance and early
Baroque to be played with pure intonation.
This instrument offers a unique opportunity to become acquainted with
the special character of temperaments using pure thirds.
From CD Sony Classical, 'Vivarte' series, No. 82876811832: Scipione
Lacorcia, Terzo Libri de Madrigali a Cinque Voci (1620), Gesualdo
Consort Amsterdam, Harry van der Kamp cond.