ardor vs changeableness

ardor

noun
  • Intense heat. 

  • Great warmth of feeling; fervor; passion. 

  • Spirit; enthusiasm; passion. 

changeableness

noun
  • the condition of being able to suffer some changes 

  • the condition of being changeable 

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