effervescence vs optimism

effervescence

noun
  • Vivacity. 

  • The escape of gas from solution in a liquid, especially the escape of carbon dioxide from a carbonated drink. 

  • Foment. 

optimism

noun
  • the doctrine that this world is the best of all possible worlds 

  • a tendency to expect the best, or at least, a favourable outcome 

  • the belief that good will eventually triumph over evil 

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