life preserver vs shillelagh

life preserver

noun
  • A buoyant ring or vest intended to keep a person afloat. 

shillelagh

noun
  • A wooden (traditionally blackthorn (sloe) wood) club ending with a large knob. 

  • Any cudgel, whether or not of Irish origin. 

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