@misc{indiciae66b330c8dd06,
  title = {Negretti \& Zambra's encyclopædic illustrated and descriptive reference catalogue of optical, mathematical, physical, photographic and standard meteorological instruments, manufactured and sold by them — Illustration, Page 231},
  year = {1887},
  url = {https://www.biodiversitylibrary.org/page/16784069},
  note = {Source identifier: page-16784069}
}