deepening vs dilatation

deepening

noun
  • The act of becoming deeper. 

dilatation

noun
  • The act of dilating; expansion; an enlarging on all sides; the state of being dilated 

  • Prolixity; diffuse discourse. 

  • A dilation or enlargement of a canal or other organ. 

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