Analysis of He, when young Spring protrudes the bursting gems

He, when young Spring protrudes the bursting gems,
Into his freshened soul; her genial hours
He full enjoys; and not a beauty blows
And not an opening blossom breathes in vain.
In summer he, beneath the living shade,
Such as o'er frigid Tempe wont to wave
Or Hemus cool, reads what the Muse, of these
Perhaps, has in immortal numbers sung:
Or what she dictates writes: and, oft an eye
Shot round, rejoices in the vigorous year.
When Autumn's yellow lustre gilds the world,
And tempts the sickled swain into the field,
Seiz'd by the general joy, his heart distends
With gentle throes, and through the tepid gleams
Deep-musing, then he best exerts his song.