J. Grunow, New York No. 976

An advanced version of the Physician's Model, c. 1889

Microscope with a swinging sub-stage for oblique illumination

J. Grunow, New York No. 976 microscope
J. Grunow, New York No. 976 microscope
J. Grunow, New York No. 976 microscope
J. Grunow, New York No. 976 microscope
J. Grunow, New York No. 976 microscope
J. Grunow, New York No. 976 microscope

 

J. Grunow, New York No. 976 microscope

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.

J. Grunow, New York No. 976 microscope
J. Grunow, New York No. 976 microscope

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 Model

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.

An example of the standard Physician’s Model with serial number 990 sold at auction in 2008.

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).

 

J. Grunow, New York serial number 976

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

An Advertisement from the Laboratory Handbook

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