heavens vs welkin

heavens

noun
  • The distant sky of the sun, moon, and stars. 

intj
  • An expression of surprise, contempt, outrage, disgust, boredom, or frustration. 

welkin

noun
  • The sky which appears to an observer on the Earth as a dome in which celestial bodies are visible; the firmament. 

  • The upper atmosphere occupied by clouds, flying birds, etc. 

  • The place above the Earth where God or other deities live; heaven. 

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