horsepower vs magnetism

horsepower

noun
  • Power derived from the motion of a horse. 

  • Strength. 

  • A nonmetric unit of power (symbol hp) with various definitions, for different applications. The most common of them is probably the mechanical horsepower, approximately equal to 745.7 watts. 

  • A metric unit (symbol often PS from the German abbreviation), approximately equal to 735.5 watts. 

magnetism

noun
  • Power of attraction; power to excite the feelings and to gain the affections. 

  • The science which treats of magnetic phenomena. 

  • The property of being magnetic. 

  • Animal magnetism. 

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