This part is written in the 8-notes scale. Whereas normal scales have 7 different notes, this one counts 8 (C-D-D#-F-F#-G#-A-B-C) or all the steps up are 1 tone, 1/2 tone - 1 tone, 1/2 tone... throughout the scale. That implies that normal harmonic sequences are rare or incomplete and that more chromatic movements occur, which lead to somewhat unusual themes. The 8-notes scale was used a.o. by Mozart, but he harmonized in the traditional way. I limited myself to only the notes of the scale (sometimes enharmonically). There is also a variant of this scale (with the sequence of tones and half tones inversed: C-C#-D#-E-F#-G-A-A#-C).
The trio will only have short pieces in each time a different unusual scale. A reel is an old English dance in 6/8, related to the Gigue or Jig.
Please feel free to comment and have a pleasant listen!