melancholy vs mirth

melancholy

noun
  • Great sadness or depression, especially of a thoughtful or introspective nature. 

  • Black bile, formerly thought to be one of the four "cardinal humours" of animal bodies. 

adj
  • Affected with great sadness or depression. 

mirth

noun
  • The emotion usually following humour and accompanied by laughter; merriment; jollity; gaiety. 

  • That which causes merriment. 

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