This is a small chest microscope by Jean Alfred Nachet (1831-1908). It consists of a brass microscope body supported by a single pillar. The base of the pillar has a broad rectangular base with a central locating pin and two side mounting screws, which allows it to be bolted to the stage in its upright position. The stage is hinged to a brass mount, which is bolted to the interior of the mahogany chest. The stage can be folded back into the chest for storage or folded out for microscope use. The microscope body press-fits into the slotted mount cantilevered off the main support pillar. Engraved on side is "Nachet - 17 r. St. Severin-Paris".
Coarse focus is accomplished by sliding the body up or down inside the mounting sleeve. Fine focus is built into the support pillar as a spring/screw focus mechanism. A knurled knob at the top of the pillar turns the screw thread and moves the microscope mount in fine increments. Optically, the microscope consists of three lenses: Objective, field, and eyelens The eye and field lenses are mounted in a draw tube, which is pressed into the body tube. The objective lens is a single biconvex optic and a removable aperture. With the aperture in place resolution is markedly better (by reducing spherical aberration). The stage is rectangular with a central hole. There are two spring clips screwed to the stage, but only one remains. The illuminating mirror is bolted to the under surface of the stage. The mirror has one parabolic reflecting surface. The box has 2 flat metal feet that fold out for stability. Imaging is fair, but exhibits poor contrast. Contrast and resolution can be increased by adding the aperture cover to the objective.
Camille Sebastien Nachet started work as an optician in 1839 or 1840. His son, Jean Alfred joined the firm sometime between 1849 and 1854. Alfred and grandson Albert Nachet subsequently purchased the Oberhaeuser instrument company in 1896. Alfred and Albert were both in charge of Nachet company at the time. This instrument was made by the Nachet firm during Alfred's era. Alfred Nachet owned one of the greatest collections of antique microscopes the world has ever seen: The Nachet Collection of Paris. That collection went up for sale in the 1960s, and some of the microscopes were purchased by Orville Golub. Those instruments from the original Nachet Collection were subsequently donated to the University of California, Berkeley, where they now form an important historical component of the Golub Collection at UCB.
Microscope featured 05/2016