Compound Microscope and Eyepiece, by Andrew Ross & Co., London, c. 1838

This copper alloy instrument is supported by a cylindrical pillar on a flat tripod foot. The maker's name and address are inscribed on the foot. A compass joint at the top of the pillar carries the shaped limb. The upper part of the limb has a triangular cross section and rackwork on the rear face. The body tube is held on brackets on a sleeve that can be racked up and down on the limb. The eyepiece has two lenses and pushes into the top of the body. Fine focusing is achieved by a telescoping nosepiece. A mill-edged screw on the lower, front of the body pushes on a bracket that is hinged at the rear. This draws the nose from the body. A spring retracts the nose as the screw is released. An external thread on the nose takes an objective. The mechanical stage has a plate mounted on a cylinder that fits the stage hole and allows the plate to rotate. A sliding bracket to support specimens has two pinholes and dovetails onto the stage plate. A post below the stage carries the plano-concave mirror in a horseshoe mount on a sliding sleeve.