Ye gentle visitations of calm thought--
Moods like the memories of happier earth,
Which come arrayed in thoughts of little worth,
Like stars in clouds by the weak winds enwrought,--
But that the clouds depart and stars remain,
While they remain, and ye, alas, depart!
Percy Bysshe Shelley
http://www.poemhunter.com/poem/fragment-ye-gentle-visitations-of-calm-thought/