cat-o'-nine-tails vs horsewhip

cat-o'-nine-tails

noun
  • A similarly constructed leather nine-tail whip, as used in British penal colonies and certain armies. 

  • A scourge (multi-tail whip) having nine, often knotted, whipcords, formerly used for flogging as naval punishment. 

horsewhip

noun
  • A whip for use on horses. 

verb
  • To flog or lash with a horsewhip. 

How often have the words cat-o'-nine-tails and horsewhip occurred in a corpus of books? (source: Google Ngram Viewer )