Searching for any information and/or music for the 20-note Mantel
Orchestrone by Merritt Gally.  From what I've found there were two
different sizes: a 20-note and a larger 26-note version.

Harold Draper

 [ 20 note Mantel Orchestrone by Merritt Gally - interior.
 [ http://www.mmdigest.com/Attachments/16/08/05/160805_094003_Mantel%20Orchestrone%201.JPG
 

 [ 20 note Mantel Orchestrone by Merritt Gally - exterior.
 [ http://www.mmdigest.com/Attachments/16/08/05/160805_094003_mantel%20orchestrone.jpg