PACINI MONOCULAR COMPOUND MICROSCOPE Filippo Pacini was an Italian instrument maker who excelled in microscope design and construction during the mid nineteenth century. The microscope illustrated below is an example of the microscopes produced by Pacini. An original version of the microscope was photographed and described by Gerard Turner in his book Catalogue of Microscopes. The base is a flat semi-circular brass plate, similar to another Pacini microscope featured in the museum, supported by three short tapered feet, with the limb and two large columns emerging from the flat surface. This version has longer feet than its cousin, the rotatable stage is not divided, and the eyetube/ocular combination is much shorter. In addition, this Pacini model has an Amici prism with an aperture on a hinged brass arm that protrudes from the front of the stage. An oval stage housing is positioned at the top of the columns and has plenty of room to accommodate a wide spectrum of specimens. The back portion of the stage is supported by a large rectangular brass limb, which contains a trapeze-sectioned bar carrying the arm to which the body tube is attached.

This inner bar is attached to a locking screw that controls a long vertical iron screw serving as the fine focus mechanism through a knurled wheel positioned under the base. A circular stage has 360-degrees of rotation and can be translated in the Y-direction by a screw with a calibrated wheel on the back of the pillar. Below the stage is a set of four apertures and a single-lens condenser that can travel up and down on a brass rod. Light is projected into the condenser lens by means of a plano-concave mirror. OBERHAUSER HORIZONTAL MONOCULAR COMPOUND MICROSCOPE Georges Oberhauser, a renowned European optician, manufactured this brass compound microscope sometime between 1835 and 1840. Designed for versatility, the drum-style monocular, which is part of the Billings collection at the Walter Reed Army Hospital in Washington DC, is shown in a horizontal microscope configuration. The Fraunhofer-style microscope can be mounted on a circular, leaded base on top of a storage box or on a 7.88-inch tubular pillar for horizontal use, as illustrated above. The tubular pillar may also be screwed into the leaded base or storage box to complete the microscope stand, though this configuration is not illustrated.

An internal 1.25-inch mirror receives light through a cutout portion of the French microscope’s drum-shaped, receiving tube, and a bull’s-eye condenser on a hinged arm may be swung into place for illuminating opaque specimens. Although the instrument does not feature a substage condenser, a revolving disc of diaphragms for adjusting the illumination and resolution of transparent specimens viewed under transmitted light is included. CHARLES CHEVALIER MONOCULAR COMPOUND MICROSCOPE Built around 1839, this microscope is a smaller version of Chevalier’s universal microscope. The original model, from which our 3-D Studio Max drawing is derived, resides in the Billings Microscope Collection at the National Museum of Health and Medicine at Walter Reed Army Hospital in Washington, D. C. The tripod base supports a cylindrical pillar that has a compass joint at the top, to which a short horizontal arm is attached. Both the horizontal microscope body tube and a vertical square limb are attached to the arm. On the limb is a rectangular stage which is moved up and down with a rack and pinion mechanism to focus the microscope. Clips on the stage are used to secure the specimen. Beneath the stage is a double mirror, which is flat on one side and concave on the other. The body tube slides on the prism box and has a single compound ocular with a breechlock fitting. The objective is threaded and fits into the bottom of the prism box.