cloakroom vs thunderbox

cloakroom

noun
  • A lavatory, now particularly a small secondary lavatory or a men's room. 

  • A room intended for holding luggage, as at an airport. 

  • A private lounge next to a legislative chamber. 

  • A room intended for holding guests' cloaks and other heavy outerwear, as at a theater or night club. 

thunderbox

noun
  • Any lavatory or toilet, especially a rudimentary outdoor latrine or toilet, or an outhouse. 

  • A box of metal balls which is shaken to create a thunder sound effect. 

  • A chamber pot enclosed in a box; a portable commode. 

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