Shelley published “The Cloud” in the Prometheus Unbound volume, appearing in July 1820; he had probably composed the lyric in the early months of that same year. Shelley's lyric was poetically inspired by the opening song of the cloud nymphs (or Nepheliads) in Part II of Leigh Hunt's “The Nymphs”, who exclaim in the first-person that it is they “[w]ho bring the clouds from the great sea” (Foliage, 1818, p. xxxi). “The Cloud” draws on Shelley's avid scientific observations and reading, in particular Luke Howard's work on cloud classification in his Essay on Clouds (1803) and the hydrological speculations of Adam Walker (who lectured during Shelley's days at Seyon Academy and Eton), which were …
Sandy, Mark. "The Cloud". The Literary Encyclopedia. First published 21 March 2002; last revised 30 November -1.
[http://www.litencyc.com/php/sworks.php?rec=true&UID=7303, accessed 18 April 2015.]