on dit vs scuttlebutt

on dit

noun
  • A flying report; rumour. 

scuttlebutt

noun
  • Gossip, rumour, idle chatter. 

  • A keg of drinking water with a hole cut in it, on board ship. 

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