I'm having a little bit of difficulty interpreting the glissando in the attached picture. It can be found at the bottom of p.25 of the score (there's only one edition floating around on the internet/IMSLP).
The notes as written are:
B-flat/C-flat, A-flat/B-dbl-flat, G-flat/A-dbl-flat, E-flat/F-flat, D (natural), D-flat/E-dbl-flat, C/D-dbl-flat, C-flat.
Considering that it's intended to be played as a glissando - and specifically with the fingers 2-1 - I think there's a misprint. To me it would make more sense as:
B-flat/C-flat, A-flat/B-dbl-flat, G-flat/A-dbl-flat, G-dbl-flat, E-flat/F-flat, D (natural), D-flat/E-dbl-flat, C/D-flat, D-dbl-flat, C-flat.
In this way, the single notes and top note of each dyad form a white key glissando, played by the thumb, and the second finger hits the black key immediately below (when there is one).
Question 1 - Is there any way that the text as written could be correct / played as a glissando with the given fingers?
Question 2 - Do you think the intention is to keep this pattern all the way through the "second part" of the glissando, or does it turn into just a white key glissando after that first octave?
My thinking is that its the latter because if it were the former, C-flat at the beginning of the line going down would have been a B-flat/C-flat dyad
Question 3 - Does anyone know what that symbol at the very bottom right below the staff means?
Topic: Respighi concerto in modo misolidio glissando