In MMD 18.04.24 Gérard Dabonot asked for the scale for 30-note Piano
Melodico.  I published this scale, and those for the other versions of
Piano Melodico as well as much more details of the construction of
these rare instruments, in "Das Mechanische Musikinstrument, Nr. 90,
August 2004, pages 7 to 19 :  C.F.C.  Greinacher: Piano Melodico - Eine
Familie mechanischer Musikinstrumente".  You can find this publication
via the Internet under
https://www.musica-mechanica.de/media/PDF/Melodico.pdf 

An English version of this paper was published in "Carousel Organ, The
Journal of the Carousel Organ Association of America,  #14, January
2003, p. 14 - 22, Dr. Christian F.C. Greinacher: Piano Melodico - A
family of mechanical musical instruments", and in "The Music Box, The
Journal of the Musical Box Society of Great Britain", Vol. 21, Nr. 3,
Autumn 2003, p. 89 - 97, same title.

I think this publication does answer Gérard's and many other questions
concerning the Piano Melodico.  Some very details of the 30-note Piano
Melodico are documented in "Restaurierungsbericht Nr. 2, Piano Melodico,
C.F.C. Greinacher".  You could find and download this restoration
report from
https://www.lulu.com/shop/search.ep?keyWords=greinacher&type=&pn=1 

Greetings from Germany,
Christian Greinacher