precarious vs quicksilver

precarious

adj
  • Dangerously insecure or unstable; perilous. 

  • Relating to incipient caries. 

  • Depending on the intention of another. 

quicksilver

adj
  • Unpredictable, erratic or fickle; mercurial. 

verb
  • To overlay with quicksilver. 

  • To treat with quicksilver. 

noun
  • The metal mercury. 

  • An amalgam of mercury and tin applied to the backs of mirrors, quicksilvering. 

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