calumet vs peace pipe

calumet

noun
  • A clay tobacco-pipe used by American Indians, especially as a symbol of truce or peace. 

peace pipe

noun
  • A tobacco pipe smoked ceremonially in certain Native American cultures that symbolizes peace among those who smoke it, and among whom it is passed around from person to person. 

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