Compound microscope

This microscope's tube has a consistent diameter. The eyepiece is at the top and the lens is at the bottom. On the back of the pillar is a screw to enable fine focusing. The tube is screwed into an arm that protrudes from the triangular moving part of the pillar. It moves vertically on a moving rack mechanism with 2 side screws for coarse focusing. The pillar is inserted into a round drum. Fine focusing is achieved by slight movements of the tube, controlled with a screw on the back. The rectangular stage has small holes in the corners for magnifying glasses or clips. Under the stage is a disc with different-sized holes used as a diaphragm to control the intensity of the light being reflected by the concave mirror below. The double pedestal is curved and at the top is a joint system that allows the microscope to tilt. The base is horseshoe-shaped. At the back of the join between the legs is an inscription identifying the manufacturer: "APPS 433 Strand. London."

Alfred Apps (1839–1913) was a maker of optical, mathematical, and philosophical instruments. He worked from No. 433 on the Strand in London between 1866 and 1911.