hand glass vs reflecting telescope

hand glass

noun
  • A small mirror with a handle. 

  • A small glazed frame for the protection of plants. 

reflecting telescope

noun
  • A telescope which produces a magnified image by reflecting light through a series of mirrors housed in a tube, using a large curved mirror to gather the light and one or more additional mirrors to transmit the light to an eyepiece. 

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