ephemerality vs fugacity

ephemerality

noun
  • The state or condition of being ephemeral; transience. 

  • Something that is ephemeral. 

fugacity

noun
  • Transience. 

  • A measure of the tendency of a fluid to expand or escape. 

  • A measure of the relative stability of different phases of a substance under the same conditions. 

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