empyrean vs the wide blue yonder

empyrean

adj
  • Of the sky or the heavens; celestially refined. 

noun
  • The region of pure light and fire; the highest heaven, where the pure element of fire was supposed by the ancients to exist: the same as the ether, the ninth heaven according to ancient astronomy, and Dante's poem. 

the wide blue yonder

How often have the words empyrean and the wide blue yonder occurred in a corpus of books? (source: Google Ngram Viewer )