jack-o'-lantern vs will o' the wisp

jack-o'-lantern

noun
  • A carved pumpkin whose top and stem have been cut out and interior removed, leaving a hollow shell that is then decorated to represent a face, illuminated from within by a candle. It is a symbol of Halloween. 

  • A similar item made from a turnip 

will o' the wisp

noun
  • A flickering light or lantern, especially over bogs, swamps or marshes, held by a supernatural creature who uses it to lure travelers at night to their demise. 

  • A delusionary or otherwise unachievable goal that one feels compelled to pursue. 

How often have the words jack-o'-lantern and will o' the wisp occurred in a corpus of books? (source: Google Ngram Viewer )