esprit vs fervour

esprit

noun
  • Spirit, enthusiasm. 

  • Liveliness, or active mind and spirit. 

  • A wit. 

fervour

noun
  • An intense, heated emotion; passion, ardour. 

  • Heat. 

  • A passionate enthusiasm for some cause. 

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