dampproof vs wetproof

dampproof

verb

  • To make resistant to the effects of damp. 

adj

  • Resistant to the effects of damp. 

wetproof

verb

  • To make waterproof. 

adj

  • Waterproof. 

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