bibcock vs sillcock

bibcock

noun
  • An appliance (typically a valve with a threaded outlet) allowing the provision of hose connections outside of buildings. 

sillcock

noun
  • A faucet designed to be installed horizontally on the outside wall of a building, typically to attach a hose. 

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