quicksilver vs sporadic

quicksilver

adj
  • Unpredictable, erratic or fickle; mercurial. 

noun
  • The metal mercury. 

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

verb
  • To overlay with quicksilver. 

  • To treat with quicksilver. 

sporadic

adj
  • Rare and scattered in occurrence. 

  • Exhibiting random behavior; patternless. 

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