Tellurian vs tellurian

Tellurian

noun
  • An inhabitant of the Earth. 

tellurian

adj
  • Of a mineral: containing tellurium. 

  • Of or relating to the earth; (specifically, chiefly science fiction) inhabiting planet Earth as opposed to other planets. 

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