lecture vs rap over the knuckles

lecture

verb
  • To preach, to berate, to scold. 

  • To teach (somebody) by giving a speech on a given topic. 

noun
  • a class that primarily consists of a (weekly or other regularly held) lecture (as in sense 1) 

  • A berating or scolding. 

  • A spoken lesson or exposition, usually delivered to a group. 

rap over the knuckles

How often have the words lecture and rap over the knuckles occurred in a corpus of books? (source: Google Ngram Viewer )