lathering vs tanning

lathering

noun
  • The act of lathering; a covering with lather. 

tanning

noun
  • The process of making leather, which does not easily decompose, from the skins of animals, which do. 

  • The acquisition of a tan, either by exposure to the sun, or artificially. 

  • A spanking. 

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