dispersal vs evanescence

dispersal

noun
  • The act or result of dispersing or scattering; dispersion. 

  • A dispersal prison. 

evanescence

noun
  • The event of fading and gradually vanishing from sight. 

  • The act or state of vanishing away; disappearance. 

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