bullwhip vs cat-o'-nine-tails

bullwhip

noun
  • A whip made from plaited leather, often with a knotted end, for use with livestock. 

verb
  • To beat with a bullwhip. 

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. 

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