Picturolls, made by the Filmusic Company of Los Angeles, allowed any
operator of the player piano or photoplayer (one which had an 88 note
tracker bar) to supply music according to the mood of the silent movie.
Love scenes would require a "smoochie, love" type of music while chase
scenes would require more exciting music.  The Picturolls came in many
designations with enough to fulfill any  mood that came up.  I owned and
played a Style 20 Fotoplayer made by the American Photoplayer Company for
years until recently and it was fun using a number of rolls to highlight
the silent movie.  Mary Jo (my wife) and I are Charlie Chaplin aficionados
and we enjoyed projecting a silent move such as "The Tramp" and using the
Picturolls to set the scene.  I wrote an article about the Fotoplayers
several years ago (early 1980's) and it was published in the Musical Box
Society Journal.  Hope this helps!

Ron