A Societe Genevoise Frauenhofer's Model 2077 Compound Screw Micrometer Microscope, circa 1900
13 inches high (33.0 cm) (base)

PRIVATE WEST COAST COLLECTION

Compound Toolmaker's/Clockmaker's Microscope. "Societe Genevoise, Pour La Construction D'Instruments De Physique Geneve" on metal label inside box. A 1900 trade catalog describes this instrument as Model 0277, Frauenhofer's Screw Micrometer with telescope or microscope of low power. Priced at 350 sF. 6-1/2"body tube slides in a clamp for coarse adjustment. Stage slides on a dove-tail bar. 2 folding legs with leveling screws and 1 fixed leg. 1-3/4" plano-concave mirror on a swinging arm. Screw-in fitting in center of stage has a 1/16" dia. hole for a pin point source of light. Single ocular, cross hairs in an assembly in the body tube which are adjustable as in a surveying instrument. 3 screw-on oculars with working distances of approximately 1-1/4", 2" and 5". Body tube can be moved over a horizontal range of 3 cm with a precision lead screw with a vernier readout in increments of 0.002mm. Body tube rotates 360º with a vernier readout in increments of 0.1º. Frame pivots to allow measurements in a vertical plane. Very robust all brass construction, lacquered with blackened accents. Solid fitted hardwood box with lock and key. Metal plaque on outside lid, "145".

Minor losses of silvering to mirror, errant scratches, some patination spotting, with wear commensurate with age and use.