I really liked this, ecspecially since right now we're working on an actual passacaglia in band. I know that Ron Nelson's passacaglia on BACH is a completely different style piece and time period when compared with Dido and Aeneus, but its the only real passacaglia that is fresh in my mind. I don't even know if that is what this is considered, or if the bass function is just an ostinato with different variations... but when I heard it I think 10 different times, I thought of a passacaglia.
I think the first variation begins in m.14, and then the second one is in m.35 with the clear return of the dotted rhythm, or at least that is what I listened for.
I felt like the piece was a simple or continuos binary with a clear A and B section but no return on the A section to close the piece.
The A section was comprised of two phrases, antecedent and consequent, with a half cadence then a PAC, and the B section is formed the same way. I thought that it was interesting that the lyrics of the sections were like a statement and then response, so that the lyrics of the B sections were a response to the lyrics of the A section. This might be a normal thing that isn't even important and I just noticed it because I'm not a singer, but I thought that it was neat.