This is a beautiful arrangement of the familiar tune Londonderry Air
I heard this piece on Todd Wilson's CD "In a Quiet Cathedral" many years ago and fell in love with it. Although the notes themselves aren't difficult, I have found it very challenging from a musical standpoint, trying to keep everything smooth as silk with a flowing legato, using a lot a rubato, and manipulating two expression pedals at the same time! I've been playing it for years and It's still a work in progress!
In the second treatment of the tune, Lemare calls for the Vox Humana and a soft celeste for the melody so I've taken the Vox from the Recit and coupled to the Salicional and Unda Maris from the Positif. He specifies the harp to play the arpeggios above the Vox Humana melody, but since there isn't one on the PAB, I chose the 8' Harmonic Flute from the Grand Orgue.