The mystery instrument is a perfectly standard Aeolian 65/88-note
Pianola!  There are two tracking ears, plus a changeover switch to
the left underneath the tracker bar.  The switchover device sits
behind the spool box, and is a work of art, beautifully machined.

For serious players this is a choice instrument, with its two scales,
Themodist accenting and a Pianola stack.  Very nice, worth snapping up.

Julian Dyer