The Witch of Atlas: Phosphor reading by her own light

The Witch of Atlas as a visionary rhyme.  How Percy Shelley's ottava rima differs from Byron's (we go to this late poem in his career in order to make the comparison).  Some attempt to understand the politics of the poem.  The sleepers.  The unimportance of reality when compared to vision.  What's Shelleyan about this.  What Empson calls the self-involved simile: moving in the light of its own loveliness; concealing only their scorn of all concealment; lying in her own shadow.  (Stevens: "Phosphor reading by his own light.")