dowsing vs rhabdomancy

dowsing

noun
  • The practice of seeking water or other substances (usually liquid) with the aid of a forked stick or similar pointing device, as believed by some practitioners to derive from supernatural power. 

rhabdomancy

noun
  • Divination with wands or rods, especially to use a divining rod to find things below the ground. 

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