evaporation vs lengthening

evaporation

noun
  • The process in which all or a portion of liquid (in a container) is turned into vapour, in order to increase the concentration of solid matter in the mixture. 

  • The process of a liquid converting to the gaseous state. 

lengthening

noun
  • a type of sound change when a sound (especially a vowel) lengthens 

  • The process of making or growing longer. 

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