fulminate vs speak out

fulminate

verb
  • To issue as a denunciation. 

  • To make a verbal attack. 

  • To thunder or make a loud noise. 

noun
  • Any salt or ester of fulminic acid, mostly explosive. 

speak out

verb
  • To assert or promote one's opinion; to make one's thoughts known. 

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