After dark vapors have oppress'd our plains
For a long dreary season, comes a day
Born of the gentle South, and clears away
From the sick heavens all unseemly stains.
The anxious month, relieved of its pains,
Takes as a long-lost right the feel of May;
The eyelids with the passing coolness play
Like rose leaves with the drip of Summer rains.
The calmest thoughts came round us; as of leaves
Budding -- fruit ripening in stillness -- Autumn suns
Smiling at eve upon the quiet sheaves --
Sweet Sappho's cheek -- a smiling infant's breath --
The gradual sand that through an hour-glass runs --
A woodland rivulet -- a Poet's death.

John Keats

http://www.poemhunter.com/poem/sonnet-after-dark-vapors-have-oppress-d-our-plains/