Analysis of Regret

There's a regret that from my bosom aye
       Wrings forth a dirgy sweetness, like a rain
       Of deathward love; that ever in my brain
Uttereth such tones as in some foregone way
Seem gathered from the harmonies that start
       Into the dayspring, when some rarest view
       Unveileth its Tempèan grace anew
To meet the sun—the great world’s fervent heart.
’Tis that, though living in his tuneful day,
       My boyhood might not see the gentle smile,
Nor hear the voice of Shelley; that away
       His soul had journeyed, ere I might beguile
In my warm youth, by some fraternal lay,
       One thought of his towards this may native isle.