equipollence vs equiponderance

equipollence

noun
  • The condition of being equipollent; equality of power, force, signification, or application. 

  • Sameness of signification of two or more propositions which differ in language. 

equiponderance

noun
  • The state of being equal in weight; equipoise 

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