An advanced version of the Physician's Model, c. 1889
Microscope with a swinging sub-stage for oblique illumination
The microscope came supplied with three objectives with canisters (1 1/2, 2/3, and 1/6 with correction collar),
two eyepieces with protective caps, an Abbe condenser with one Waterhouse stop, a live box, a brass and glass
slide carrier, and a triple nose-piece. The storage case has a brass handle and an internal drawer for the accessories.
This microscope dates from near the end of the 19th century. It appears
to be a more advanced and larger version of Grunow’s Physician’s Model,
which was first described in 1886. The microscope is about 15-inches
in height inclined as shown in the photos. The height can be extended via draw-tube. There is a single pillar
coming up from a Y-shaped base terminating at the inclination pivot. Coarse focusing is by rack and pinion.
There is a continental type fine adjustment mechanism. The round
stage has a built-in aperture wheel. On top of the stage is a glass
and brass slide carrier. The sub-stage consists of an Abbe condenser
which focuses by rack and pinion and a double sided mirror, both of
which are attached to a swinging arm. The swing of the arm has a locking mechanism
and is calibrated by a silvered scale. It is these latter
features that distinguishes this advanced version from the ordinary smaller Physician’s Model.
The standard Physician’s Model was described and
illustrated in The Journal of the Royal Microscopical Society, 1887 as follows:
Grunow's Physician's Microscope.-- In this instrument,
designed by Mr. J. Grunow (figs. 35 and 36), the whole stand is of brass,
with rack-and-pinion coarse, and micrometer-screw fine-adjustments. The
stand can be inclined to any angle. The mirror is mounted on a double arm,
so that it can be swung above the stage for the illumination of opaque objects
Tbe substago is on a pillar attached to the base of the Microscope, and
may be turned aside, thus facilitating the exchange of accessories without
disturbing tho object in the field.
The incorporation of this swinging sub-stage necessitated
a redesign of the sub-stage layout. While in the standard version
the condenser and mirror were on separate arms, in this advanced version,
they are located together on a single swinging arm. In the standard version the condenser
focused with a simple push mechanism having a locking screw, while in the version shown here, a rack and pinion is used.
Another feature of the advanced version is the round stage and the use of a glass slide carrier. This advanced version
is somewhat larger than the standard Physician’s Model.
Evidently, the first known use of a swinging substage
was with the microscope designed by Thomas Grubb in 1854.
Several original examples of this microscope still exist,
one of which is shown here.
However, it was the introduction of Zentmayer’s American Centennial
model in 1876 that spurred renewed interest in this feature. Almost
immediately, other manufactures in America and England assimilated
this feature into their designs. As illustrated with the microscope shown
on this page, some of Grunow's later models also incorporated this feature (for example, also see this microscope).
The Grunow brothers, Julius and William, emigrated from Germany to New York around 1849. They started in the scientific instrument business by first working for the optician Benjamin Pike of that city. By 1854, they began their own operation in New Haven CT where they concentrated on the production of microscopes. By 1864, they were back in New York. Some years later, the partnership ended. J. Grunow continued on to produce microscopes up to around 1892. The total output of the Grunows was limited in comparison to some other contemporary firms; on the basis of the observed serial numbers, they manufactured just over one thousand microscopes in total. See: a family history of the Grunows in 19th century America written by a descendant.
An advertisement from the Laboratory Handbook, 1885