Dulcimer Maker And Musician
Wow. This could be anything. The flute is an old style flute but they were in popular use well past the Turn of the Century. The guy playing the viola holds his bow in the classical manner of the time. The harmonium would have been the most portable keyboard of the era. They could be playing Shrammel quartet music, some sort of popiular music or what we think of today as folk music. My guess would be light classical. Just my 2p.