hand glass vs imager

hand glass

noun
  • A small mirror with a handle. 

  • A small glazed frame for the protection of plants. 

imager

noun
  • A system that creates a digital copy such as a disk image. 

  • One who images or forms likenesses; a sculptor. 

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