Analysis of Eugène Ysaÿe's "Harmonies du soir"

I recently stumbled upon this great piece of music by Belgian Composer and conductor.

The beginning of "Harmonies du soir" features some gorgeous harmonic movements,here is a short analysis i did.

Measures 1 to 10 go from Eb7 to G7 and back to Eb7.That would be the general harmonic direction.

The B7(bVI7 of Eb) in measure 4 is a neighbour chord to Eb7.

Interestingly enough,Eb7(bVI7 of G7) can serve as a neighbour chord to G7.(G°7 is also used)

In Jazz, the bVI7 is often considered as a altered subdominant chord ( a sort of" bluesy" modification of the bVImaj7chord which is a modal interchange), but it may also be traced back to a neighbour chord function.

"Harmonies du soir is a sensuously chromatic journey through thickly textured emotions and colours finally leading, by restlessly climbing motifs, to a glorious sunrise in C. The only documented public performance was given by the Columbia University Strings in New York in 1979. This is its first recording. "

Eugène Ysaÿe - "Harmonies du soir" for string quartet and orchestra (audio + sheet music)

Harmonies du soir, Op. 31, is a fascinating novelty. Géry Lemaire described the score as 'a messy doodle of a manuscript written in light pencil. On the last page, still in the author's hand, and ...

https://www.youtube.com/watch?v=Ku8JJwdurHg&feature=youtu.be