expiate vs rectify

expiate

verb
  • To make amends or pay the penalty for. 

  • To wind up, bring to an end. 

  • To purify with sacred rites. 

  • To atone or make reparation for. 

rectify

verb
  • To correct or amend (a mistake, defect etc.). 

  • To adjust (a globe or sundial) to prepare for the solution of a proposed problem. 

  • To restore (someone or something) to its proper condition; to straighten out, to set right. 

  • To determine the length of a curve included between two limits. 

  • To purify or refine (a substance) by distillation. 

  • To produce (as factitious gin or brandy) by redistilling bad wines or strong spirits (whisky, rum, etc.) with flavourings. 

  • To remedy or fix (an undesirable state of affairs, situation etc.). 

  • To convert (alternating current) into direct current. 

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