Analysis of Day is dying

Day is dying! Float, o song,
Down the westward river,
Requiem chanting to the Day,
Day, the mighty giver!

Pierced by shafts of Time he bleeds,
Melted rubies sending
Through the river and the sky,
Earth and heaven blending.

All the long-drawn earthy banks
Up to cloudland lifting:
Slow between them drifts the swan
'Twixt two heavens drifting,

Wings half open like a flower.
In by deeper flushing,
Neck and breast as virgin's pure
Virgin proudly blushing.

Day is dying! Float, o swan,
Down the ruby river,
Follow, song, in requiem
To the mighty Giver!