cistern vs porcelain goddess

cistern

noun
  • In a flush toilet, the container in which the water used for flushing is held; a toilet tank. 

  • The vessel surrounding the condenser in a steam engine. 

  • A cisterna. 

  • A reservoir or tank for holding water, especially for catching and holding rainwater for later use. 

porcelain goddess

noun
  • A toilet bowl. 

  • metaphor for a woman, often stressing paleness, delicateness or lack of emotion. 

  • Used other than figuratively or idiomatically: see porcelain, goddess. 

How often have the words cistern and porcelain goddess occurred in a corpus of books? (source: Google Ngram Viewer )