allay vs tranquilize

allay

verb
  • To make quiet or put at rest; to pacify or appease; to quell; to calm. 

  • To alleviate; to abate; to mitigate. 

noun
  • Alleviation; abatement; check. 

tranquilize

verb
  • To calm (a person or animal) or put them to sleep using a tranquilizer dart. 

  • To make (something or someone) tranquil. 

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