Janus vs time-server

Janus

name
  • Used to indicate an azo dye with a quaternary ammonium group, frequently with the diazo component being safranine. 

  • A moon of Saturn. 

  • A two-faced person, a hypocrite. 

  • The god of doorways, gates and transitions, and of beginnings and endings, having two faces looking in opposite directions. 

  • Used to indicate things with two faces (such as animals with diprosopus) or aspects; or made of two different materials; or having a two-way action. 

time-server

How often have the words Janus and time-server occurred in a corpus of books? (source: Google Ngram Viewer )