Ariel's Song
"Ariel's song" is a verse passage in Scene ii of Act I of William Shakespeare's "The Tempest". It consists of two stanzas to be delivered by the spirit Ariel, in the hearing of Ferdinand. In performance it is sometimes sung and sometimes spoken. There is an extant musical setting of the second stanza by Shakespeare's contemporary Robert Johnson, which may have been used in the original production. Section::::"Full fathom five". "Full fathom five" is the beginning of the second stanza of "Ariel's song", better known than the first stanza, and often presented alone . It implicitly addresses Ferdinand who, with his father, has just gone through a shipwreck in which the father supposedly drowned. It is the origin of the identically worded catchphrase, which means "at a depth of five fathoms [of water]" and thus, in most evocations, drowned and lost as the father is. Prior to modern diving technology, an object lost in five fathoms of water would be considered irretrievable. This stanza is also the source of the contemporary English usage of "sea change". Modern usage of the phrase is seldom specific to the sea or drowning, but generally refers to any  change that is holistic and seems "beyond recognition" in degree: a metamorphosis. The lines of Ariel's song do not indicate whether the "sea change" was caused by Prospero's magical powers, or simply by immersion in the sea.