emigrant vs foundling

emigrant

noun
  • Any of various pierid butterflies of the genus Catopsilia. Also called a migrant. 

  • Someone who leaves a country to settle in a new country. 

foundling

noun
  • An abandoned child, left by its parent(s), often a baby left at a convent or similar safe place. 

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