J. & W. Grunow, New Haven Conn. (attributed)

The Educational Model Microscope. c. 1860

While this microscope is unsigned by the maker, it is clearly of American origin. The shape of the cast-iron base and limb is characteristic of the early instruments made by J. & W. Grunow. In fact, except for the addition of a coarse focus by rack and pinion, this instrument appears nearly identical to the Educational Model shown in the 1857 Grunow catalog. The objective is signed Queen & Co. and may not have been originally supplied with the microscope. When purchased for this collection, the original lacquered brass surface finish was absent; it has subsequently been restored.

This microscope likely dates from the 1860's. 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.

The following is an extract from the Illustrated Scientific and Descriptive Catalogue of Achromatic Microscopes, J. & W. Grunow & Co., New Haven Conn, 1857.

Educational Microscope. This instrument is mounted on a firm tripod, with up- rights of japanned cast-iron. A solid limb of japanned cast-iron supports the stage and the body of the instrument, and being attached to the uprights by a trunnion joint, it allows the instrument to be inclined at any angle. The body of the instrument slides easily and steadily in a firm, but elastic brass cylinder, attached to the japanned limb, by which means it is readily adjusted to any desired focus. The stage is two by three inches, having spring clips to retain the object in place when the microscope is inclined.A fine screw, with a milled head, at the right of the stage, gives a fine adjustment to the focus.

Below the stage is a diaphragm plate, with orifices of different sizes to regulate the illumination, and a space between the largest and smallest orifices to exclude all the light, and give a dark background for viewing opaque objects.

A concave mirror an inch and a half in diameter, suspended by a cradle joint, and movable in every direction, is used for illuminating the object.The mirror is so attached to the axis of the instrument, by a movable arm, that it can be turned so as to give very oblique light.

This instrument is generally supplied with two eye-pieces, and with one inch and one quarter inch objectives of second quality, giving four magnifying powers, varying from 40 to 350 diameters.

This microscope is designed, as its name implies, for educational purposes, for schools, private families, and for young people generally. Farmers, mechanics and merchants, who desire to devote some of their leisure hours to intellectual improvement, or to the investigation of those branches of natural science more or less connected with their several avocations, will find this at once a cheap, substantial and efficient microscope.

As it is very steady and delicate in its adjustments, and can be used with the higher powers, the man of science will often find it a convenient substitute for the larger microscopes, when a more portable instrument is required for special purposes.

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