birch vs cat-o'-nine-tails

birch

noun
  • A stick, rod or bundle of twigs made from birch wood, used for punishment. 

  • A hard wood taken from the birch tree, typically used to make furniture. 

  • A birch-bark canoe. 

  • Any of various trees of the genus Betula, native to countries in the Northern Hemisphere. 

verb
  • To punish with a stick, bundle of twigs, or rod made of birch wood. 

  • To punish as though one were using a stick, bundle of twigs, or rod made of birch wood. 

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 birch and cat-o'-nine-tails occurred in a corpus of books? (source: Google Ngram Viewer )