brass monkeys vs glacial

brass monkeys

adj
  • very cold 

glacial

adj
  • Cold and icy. 

  • Of, or relating to glaciers. 

  • Very slow. 

  • Having the appearance of ice. 

  • Cool and unfriendly. 

noun
  • A glacial period (colloquially known as an ice age). 

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