Five 18th century artifacts, discovered over a period of 40 years in Amsterdam, at last have been identified as personal telescopes. Two of the them were found in a privy pit. The devices–representing the very cutting edge of 18th century technology–were hand-carved from bone and fitted with a pair of lenses. How such high-end tech got dumped in a cesspool remains a mystery, but the telescopes themselves are unique artifacts:
Ranging in length from roughly 3 to 5 inches (80 to 140 millimeters), the telescopes were made using cattle metatarsal bone. “This particular bone of cow, the metatarsal bone, is actually quite straight and round,” Marloes Rijkelijkhuizen, of the Amsterdam Archaeological Centre at the University of Amsterdam, told LiveScience. “It’s a nice shape to make these telescopes from, it’s straight and (has a) very round narrow cavity.”
Each telescope would have had a pair of lenses — like the system used by Galileo — a convex objective and a concave ocular, to magnify objects. (Two of the telescopes have at least one lens intact.) The longest of the telescopes, which had both lenses intact, is made of two parts put together with a screw thread, and was equipped with a bone insertion that has a small hole and likely functioned as an aperture stop.