Early handheld microscope. 3 3/4" long including handle. 1 1/2" deep lens. In 1812 William Hyde Wollaston introduced an improved version of the earliest magnifiers - It's very thick biconvex / almost spherical glass with a groove around the middle, which blocks the badly distorted peripheral rays so you get a sharp, clean image at high magnification. I believe these coincided with the public interest in botany - I was told they were used for examining plant structures. White metal, not silver. c. 1850.