Compound Microscope with Accessories, by Andrew Ross, London, c. 1838 & 1861

Originally a monocular microscope, the binocular body with a symmetrical, achromatic prism was a later addition. This brass 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 tubes are held by brackets on a sleeve that can be racked up and down on the limb. The eyepieces have two lenses and push into the top of the tubes. The inter-ocular distance is adjusted by a bar with milled knob at each end that extents the eyepiece fittings from the body. Fine focusing is adjusted by a mill-edged screw on the front of the lower part of the body. An internal 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.

The accessories with this microscope are a bull's-eye lens on a stand, a spring state for glass phials, a condensing lens on a steel pin, stage forceps, four eyepieces and five objectives in cans, one with a Lieberkuhn. Only one of the objectives fits the microscope.