meth vs watch glass

meth

noun
  • A spiced mead, originally from Wales. 

  • Marijuana. 

  • Methamphetamine, especially in the form of the crystalline hydrochloride. 

  • Methadone. 

  • A tramp. 

watch glass

noun
  • A sandglass. 

  • An item of glass laboratory equipment consisting of a simple, slightly concave circle of glass. It is a general utility item, used to hold small samples, to evaporate liquids, to cover a beaker, and so on. 

  • The glass covering of the face of a watch. 

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