This is the eleventh of the twelve studies, based on the traditional tune known as Aberysthwyte, aka "Jesus, Lover of My Soul".
It's the simplest of all the studies, presenting the unadorned melody (modified to fit the natural harmonics available), and then presenting the melody over a gently droning, pulsing pedal tone before wrapping up the second presentation in a block chord chorale that leads to a modal plagal cadence coda.
https://youtu.be/GuBx3gwlNXs