bottle up vs cool down

bottle up

verb
  • To keep suppressed and hidden. 

  • To prevent (enemy vessels) from leaving an anchorage. 

  • To put into bottles. 

cool down

verb
  • To become less agitated or excited. 

  • To become cooler; to be reduced in temperature. 

  • To cause (something) to become cooler; to reduce the temperature of. 

  • To decrease in degree or intensity. 

  • To cause (someone) to become less agitated or excited. 

How often have the words bottle up and cool down occurred in a corpus of books? (source: Google Ngram Viewer )