equipoise vs equiponderance

equipoise

noun
  • A state of balance; equilibrium. 

  • A counterbalance. 

verb
  • To act or make to act as an equipoise. 

  • To cause to be or stay in equipoise. 

equiponderance

noun
  • The state of being equal in weight; equipoise 

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