empyreal vs skyly

empyreal

adj
  • Of the sky or heavens. 

  • Fiery, made of pure fire. 

  • Pertaining to the highest heaven or the empyrean 

skyly

adj
  • Of, resembling, or relating to the sky; celestial 

How often have the words empyreal and skyly occurred in a corpus of books? (source: Google Ngram Viewer )