Geneva wheel vs Maltese cross

Geneva wheel

noun
  • A mechanism that translates a continuous rotation into an intermittent rotary motion. 

Maltese cross

noun
  • Synonym of Geneva wheel 

  • A cross having four equal arms resembling arrowheads joined at the points 

  • A flowering plant Lychnis chalcedonica (syn. Silene chalcedonica) of the family Caryophyllaceae 

  • A position on the rings where the gymnast's body is horizontal and straight, with arms to the side; a horizontal planche. 

How often have the words Geneva wheel and Maltese cross occurred in a corpus of books? (source: Google Ngram Viewer )