Analysis of The Fountain Leaps as if its Nearest Goal

The fountain leaps as if its nearest goal
Were sky, and shines as if its life were light.
No crystal prism flashes on our sight
Such radiant splendor of the rainbow's whole
Of color. Who would dream the fountain stole
Its tints, and if the sun no more were bright
Would instant fade to its own pallid white?
Who dream that never higher than the dole
Of its own source, its stream may rise?
Thus we
See often hearts of men that by love's glow
Are sudden lighted, lifted till they show
All semblances of true nobility;
The passion spent, they tire of purity,
And sink again to their own levels low!