foam at the mouth vs smolder

foam at the mouth

verb
  • To rage, vent one's anger. 

  • To spew saliva as foam. 

smolder

verb
  • To show signs of repressed anger or suppressed mental turmoil or other strong emotion, such as passion. 

  • To exist in a suppressed or hidden state. 

  • To burn with no flame and little smoke. 

noun
  • The act of smoldering or something that smolders. 

How often have the words foam at the mouth and smolder occurred in a corpus of books? (source: Google Ngram Viewer )