This is a small, folding brass and ivory botanical microscope that was used as a field microscope. The instrument can be folded into a carrying case made from velum-covered cardboard. The lens is a single planoconvex lens of approximately 3x magnification. The folding handle is made from ivory. The sample holder is a small brass pin that can be slid along a brass rail for focusing. Microscopes like these were used by naturalists of the 19th Century.