The single includes two B-sides, "Delius" and "Passing Through Air". "Delius" is Bush's tribute to English composer Frederick Delius. The subtitle, "Song of Summer", comes from one of Delius' works, and from a BBC film Bush saw about the composer's life. Again, it's of note that the album version is different in that the previous track "Babooshka" segues into it, whereas the single B-side version begins unobscured. "Passing Through Air" is one of Bush's earliest works—originally recorded in 1973 at David Gilmour's studio, a few weeks after her 15th birthday.