somnific vs spellbinding

somnific

adj
  • Causing sleep; somniferous. 

spellbinding

adj
  • Engrossing; fascinating; gaining rapt attention; captivating. 

  • Having the power to bind magically through the agency of a spell. 

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