crucible vs slop-bowl

crucible

noun
  • A cup-shaped piece of laboratory equipment used to contain chemical compounds when heating them to very high temperatures. 

  • A heat-resistant container in which metals are melted, usually at temperatures above 500°C, commonly made of graphite with clay as a binder. 

  • A very difficult and trying experience, that acts as a refining or hardening process. 

  • The bottom and hottest part of a blast furnace; the hearth. 

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 crucible and slop-bowl occurred in a corpus of books? (source: Google Ngram Viewer )