necessarium vs washbowl

necessarium

noun
  • A lavatory. 

  • Synonym of reredorter: a monastery's latrine, outhouse, or lavatory, typically located behind the dormitory. 

washbowl

noun
  • A sink in a bathroom, connected to a supply of water and a drain, in which one may wash one's face and hands. 

  • A basin for washing the face and hands; a washbasin. 

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