The microscope is signed on two places, on the tube "Ernst Gundlach" and on the base "Gundlach". A similar microscope sold by Yawman & Erbe of Rochester N.Y. is also represented in this collection. It has a brass base instead of the cast iron base that is on the microscope shown on this page. The microscope shown on this page came supplied with two Gundlach objectives and two eyepieces. The main focus of the microscope can be accomplished by slip-tube or by rack and pinion, while the fine focus utilizes a micrometer screw mechanism. The mirror can be positioned at any angle relative to the stage including above the stage for illumination of opaque objects. The draw-tube is nickel plated.
In the 1882 Gundlach catalog, this model was called the Student’s Microscope No. 1.
It was described in the catalog as follows:
The mirrors are plane and concave, the latter being two inches in diameter.
The mirrors swing above the stage to any angle for the illumination of opaque
objects, and the mirror bar is graduated in five-degree spaces. The device for
keeping the friction uniform on the mirror-bar is a new one. It is a contrivance
that keeps in order and is durable. There are three adjustments: rack-and-pinion,
sliding adjustment. and micrometer screw. The rack, which is on a double-V is
very satisfactory. It is new in design and perfect in work. The fine adjustment
is an entirely new invention. It is simpler and much less expensive than the
roller motion adjustment on the College Microscope. It will be found satisfactory,
and fully adequate to the work it is intended to do. It is worked by a milled
head on top of the pillar, and it has a very much greater extent of motion than
the fine adjustments of other makers. This stand was originally devised with
reference to receiving a glass stage. A glass stage with simple slide carrier
has been devised which can be added to the stand at small expense, making it
equal to those of greater pretensions at a much lower price.
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. Additionally, the walnut storage cases for all these microscopes are distinctive and identical.
The following description of Gundlach's contributions to microscopical optics was extracted from the Proceedings of the American Society of Microscopists (1882):
ERNST GUNDLACH Was born in Pyritz, Prussia, 1834; was educated there and in Berlin, where he took a course in one of the leading workshops (C.Lewert) to learn the trade of philosophical instrument-maker; afterwards working with other firms, and always choosing those who were doing their own optical work, in the hope of adding practical knowledge to the theoretical principles of optical science with which he was already familiar. On account, however, of the habit of opticians of keeping their methods of work strictly secret, young Gundlach learned little or nothing of practical value in this special line and, in 1866, he started optical work for himself, knowing nothing of the methods of others, except that emery is used for grinding, and rouge for polishing lenses. Technical difficulties soon presented themselves, only to be overcome by the enthusiasm of the young optician, and in about six months he had completed his first microscope, with three objectives and two eye-pieces. This instrument was purchased by Prof. Berg, of the University of Berlin, who, though a stranger to Mr. Gundlach, recognized the fine quality of his work. The next year he exhibited at the Paris Exposition his glycerine immersion objectives, and received therefor a special medal. This Mr. Gundlach believes to be the first instance of the intentional construction of objectives for use with an immersion fluid of higher refractive index than water. A frictionless fine adjustment for microscope stands was another of his inventions about this time.
In 1873 Mr. Gundlach, who had already become recognized as one of the greatest of living opticians, removed to this country and located at Hackensack, N. J. His first work here was the construction of two water immersion objectives (a 1/6 and 1/16 for Prof. Thacker, of Cincinnati, O., which won the admiration of many very competent judges, including Dr. Woodward, of the U. S. A. Medical Museum, Washington, D. C. In 1875, Mr. Gundlach invented his so- called “glycerine adjustment,” in which, by means of a layer of heavy glycerine of variable thickness confined between the front of the anterior lens of the objective and a plane glass cover, compensation is made for varying thickness of cover glass without alteration of optical adjustment or change of magnifying power.
In 1876 Mr. Gundlach brought out his hemispherical condenser and his periscopic eye-piece, the latter being an improvement on the orthoscopic ocular of Kellner.
In 1879 he discovered a new optical principle, upon which the construction of his globe lens is based. The construction of this lens is very peculiar, consisting of a solid and perfect globe of crown glass enclosed in cement within a hollow globe of flint glass, the corrections being obtained by the thickness of the flint.
In 1880 Mr. Gundlach produced a series of homogeneous immersion objectives, having apertures of 136° in balsam (1.41 N. A.), and combining remarkable working distance with most excellent corrections and performance.
Mr. Gundlach has also made some notable contributions to the literature of microscopical optics, among which may be mentioned his discussion of numerical working distance of objectives, and a new method of measuring apertures from 87° to 1800 in crown glass (1.14 to 1.52 N. A.) It will be seen that, so far as practical optics is concerned,'Mr. Gundlach is an autodidact, as, from the secrecy maintained by European opticians in regard to their methods of work, he was unable to learn but little, if anything, and was forced to work out his methods for himself.
Additional information about the Gundlach businesses in America is online.
See this essay about Ernst Gundlach and his microscopes.
Gundlach 1878 advertisment
