Sonate F-Dur "Das Lied vom Rhein"

Now that my opus 11 - the well-tempered organ - has been completed, I have taken a longer break.
Then, the day before yesterday, I took a look in the "Lahrer Kommersbuch" and found a song, namely "Das Lied vom Rhein". When I look out of my window, I can see it about 100 meters away, the "Vater Rhein" at river kilometer 654. It's beautiful, after a few days of high water the river level has dropped again, but the river still seems well filled and very sublime.

The song of the Rhine, the melody was written by Hans-Georg Nägeli around 1816.
What I immediately think of when I think of the year 1816 is this:

The unusually cold year of 1816, especially in the north-east of America and the west and south of Europe, is known as the year without a summer. In the United States it was nicknamed "Eighteen hundred and froze to death", and in Germany it also became notorious as the year of misery "Eighteen hundred and froze". Today, the main cause is considered to be the eruption of the Indonesian volcano Tambora in April 1815, which volcanologists classify as significantly more powerful than the eruption of Mount Vesuvius in 79 AD and that of Krakatau in 1883.

Nägeli (perhaps) therefore wrote this song in this year and under the impression of this climatic event.
I used the melody as a model for this sonata. A 3-movement work, a song movement, a trio and an essentially 3-part fugue, which is extended by the pedal in the coda.
I will dispense with a concluding dacapo of the song movement, as the magnificent melody can be clearly heard in the pedal.

We hear the wonderful Mascioni Organ in Giubiasco.