glass harp vs glassichord

glass harp

noun
  • A musical instrument consisting of glasses (typically wine glasses) tuned by putting different amounts of liquid into them. Sound is produced by rubbing one's fingers around the rims of the glasses, causing them to vibrate. 

glassichord

noun
  • A 19th-century musical instrument made of glass plates that are struck by hammers or sticks. 

  • Synonym of glass harmonica 

  • Anything that produces a similarly pure continuous sound. 

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