Usage/History: This microscope is designed to provide
low magnifications of objects in three dimensions. Widely used
for dissections, small parts assembly and inspection, jewelry
inspection and similar operations requiring an enlarged, stereoscopic
view, these instruments consist of two independent microscopes.
Each has an erecting prism system and is focused on the same
object from a slightly different angle to give an exaggerated
stereoscopic view. Because of the inclinations of the optical
axis of the two microscopes from the vertical, only the center
of the field is in focus for both, however the composite image
appears sharp over the entire field due to the opposite nature
of the focusing errors, the accommodation of the eye, and the
great depth of view of the low power objectives. This type of
low power, binocular microscope was first designed by Greenough
in 1897, and was first manufactured by Zeiss using standard microscope
optics.1 Leitz was the first manufacturer to significantly
improve the design with the use of large diameter (1.25"),
well corrected eyepieces giving a bright, flat, and large field
of view.2
Description: Greenough type "binocular"
microscope; 10.5 x with two a15 oculars (1 1/4" diameter).
The body consists of two binocular like leather covered tubes,
6" long, enclosing porro prism erecting optics, which may
be rotated to accommodate inter ocular distance. The body is
mounted through a brass dovetail to a focusing rack which is
in turn mounted through a second dovetail to the arm (the rack
may be removed). An 11" articulated black painted brass
arm rotates 360° on a focusing sleeve which rides on a 14"
pillar with rack and pinion movement. The pillar is attached
to a heavy, solid, round cast iron base, 7" dia x 1 3/4"
high at post. All exposed metal parts are nickel plated or black
wrinkle enameled. There is a serial number? (6420) stamped on
a plate on the top of the optical module focusing/mount mechanism.
Research: Similar to Ernst Leitz Stand (dated 1925)
as illustrated in The Billings Microscope Collection, 2nd ed,
figure 275 (signed "E. Leitz, Wetzlar, Germany, 2624").
What appears to be an identical stand is illustrated in the 1927
Eimer & Amend BCM Catalog (Eimer & Amend, New York, 1927)
as item 26334 on pg 495. The optical portion is of an earlier
design, but the optical unit is also illustrated in the catalog
on pg 498 on a standard stand as item 26370. This microscope
was a gift from Dr. William Allen of HSU's Biology Department.
He later stated that he believed it had originally been William
Lanphere's.
1 Needham, George Herbert. The
Practical Use of the Microscope. Charles C. Thomas Publisher.
Springfield. (1958) p. 64.
