To add to the good explanations given by Francoise Dussour, you may
have a look at a very good web site relating the fascinating history of
a mechanical piano maker in Nice, Nallino, created in 1872 by Joseph
Nallino, the great grand father of the author of these pages, Michel
Nallino : http://perso.club-internet.fr/mnallino/
For those who have no access to the web, this story was published too
in the AAIMM Journal Musiques Mecaniques Vivantes, issue 27, 3d Trim.
1998, pp 13-27.
Best regards from Paris,