Hi, in the framework of a doctoral dissertation on (simply put) 'non-traditional' piano playing techniques, I'm researching - amongst others - the genesis of the glissando. I found two instances in Beethoven's works (in opus 15 and 53). My questions:
1. If I paid a visite to the Beethoven Haus, would it be possible for me to find out whether the glissandi were included in the earliest sketches for these particular works (did these survive)?
2. Did anybody (contemporary to B.) write about these glissandi? (e.g. reviews of in performances by Beethoven / when considering performance practice?)
3. Is there any existing research as to where B. might have gotten the idea for octave glissandi if he wasn't the first to think of them?