Yawman & Erbe Rochester N.Y., c. 1884

Engraved on the fine adjustment knob: Pat. Aug. 15, 1882

Yawman & Erbe Rochester N.Y., c. 1884. Engraved on the fine adjustment knob: Pat. Aug. 15, 1882 Yawman & Erbe Rochester N.Y., c. 1884. Engraved on the fine adjustment knob: Pat. Aug. 15, 1882 Yawman & Erbe Rochester N.Y., c. 1884. Engraved on the fine adjustment knob: Pat. Aug. 15, 1882

Yawman & Erbe Rochester N.Y., c. 1884. Engraved on the fine adjustment knob: Pat. Aug. 15, 1882

Yawman & Erbe Rochester N.Y., c. 1884. Engraved on the fine adjustment knob: Pat. Aug. 15, 1882

Yawman & Erbe Rochester N.Y., c. 1884. Engraved on the fine adjustment knob: Pat. Aug. 15, 1882. Accessories

Among the accessories are two Gundlach objectives, a 1/4-inch and a divisible 2/3 and 1-inch objective both with canisters, two eyepieces (one incomplete), an eyepiece micrometer, a camera ludica, a live box, a Holman's live slide, and a set of dissection tools. The stage can accommodate two stage clips or an accessory glass stage with an articulated nickel plated slide carrier. The sub-stage consists of a wheel of diaphragms.

 

Yawman & Erbe Rochester N.Y., c. 1884. Engraved on the fine adjustment knob: Pat. Aug. 15, 1882. Differtential screw

This description of the differential screw fine adjustment was extracted from The Odontographic Journal, 1881. It was patented by Philip Yawman on Aug. 15, 1882

The same gentleman also exhibited a new fine adjustment for microscope stands, invented and manufactured by Messrs. Yawman & Erbe, of this city. What are commonly called fine adjustments rarely get beyond one hundred threads to the inch, but this a differential screw, which is “a compound screw by which a motion is produced equal to the difference of the motions of the component screws ”—gives a movement equal to three hundred and sixty threads to the inch. This exceedingly fine movement may be reduced, by loosening a conveniently placed milled-head screw, to sixty threads to the inch, an adjustment sufficiently fine for all low power objectives. This fine adjustment is attached to all stands made by this firm, and may at slight expense be attached to stands of other manufacture. All microscope stands made by Messrs. Yawman & Erbe have three adjustments: 1st. The rack and pinion common to all good instruments; 2d, The ordinary fine adjustment as used on first-class instruments generally; and 3d, What may be called their superfine adjustment, the differential screw. It was on a stand fitted with this superfine adjustment that Major Streeter was enabled to “show off ” his highly-prized one-eighth objective, which he did under most unfavorable circumstances, resolving and resolving the Amphipleura pellucid of Mr. Main's test-plate, a feat that with the ordinary fine adjustment had often consumed fifteen minutes in its accomplishment.

Yawman & Erbe Rochester N.Y., c. 1884. Engraved on the fine adjustment knob: Pat. Aug. 15, 1882. Storage case

Yawman & Erbe Rochester N.Y., c. 1884. Engraved on the fine adjustment knob: Pat. Aug. 15, 1882. In storage case

 

 

Philip Yawman and Gustav Erbe were both employees of Bausch & Lomb. In 1880, they left that firm to start their own business in Rochester New York. For the greater part of the life of the firm, Yawman & Erbe primarily were involved in the manufacture of office furniture and equipment. However, for a very brief period in the early 1880's they manufactured microscopes. It appears that the production of microscopes was in collaboration with Ernst Gundlach, another former B&L employee. It is clear that it was Gundlach who produced the optics, but it is less clear which firm actually manufactured the stands. Both firms often sold the same model microscopes and, in fact, there are microscopes that bear dual signatures by both firms. For example, see the two "Nonpareil" model microscopes in this collection. Also, see this Gundlach signed microscope which is very similar to the instrument shown on this page with the exception of having a cast iron base instead of a brass base. Additionally, the walnut storage cases for all these microscopes are distinctive and identical. While the furniture produced by the Y&E is now rather common, the microscopes are far less so. The early history of the Yawman & Erbe firm has been documented.

There are labels in the storage case indicating that the microscope was retailed by Schmidt & Kaelber of Rochester N.Y.

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