pannikin vs slop-bowl

pannikin

noun
  • A durable cup or other vessel used for drinking made of metal and coated in enamel. 

  • The contents of such a vessel. 

slop-bowl

noun
  • Part of a traditional tea set, used to empty the cold tea and dregs in tea cups before refilling with hot tea. Usually pottery or silver. 

How often have the words pannikin and slop-bowl occurred in a corpus of books? (source: Google Ngram Viewer )