cumshaw vs furtherance

cumshaw

noun
  • A gratuity or tip as thanks for a service 

verb
  • To give or make a present to. 

furtherance

noun
  • Promotion. 

  • Advancement or progress. 

  • The act of furthering or helping forward 

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