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Compound achromatic microscope, stand III C

Maker

ZEISS

Country

Germany

Signature

CARL ZEIS / JENA / 51768

Category

Microscopes

Optical 1

Compound

Optical 2

Achromatic

Size of the microscope (h x b x d)

32.5 × 13 × 15.5 cm

Inventory number

SM 33

Description

Stand type III C, its nick name is ‘Bierseidel’ or Jug Handle, because of its characteristic grip. Zeiss introduced this stand in 1898, it was made until the nineteen twenties. A problem with the older large stands I and III was that it was usual to pick them up by their limb, the sensitive micrometer screw which was in the limb got damaged easily by this malpractice (these stands are very heavy, 7-8 kilo). In the new Jug Handle this cannot happen so easily. Zeiss introduced a new fine adjustment as well, the Berger type micrometer screw, which acted on the block carrying the body tube and the coarse adjustment.
There were two main types, stand I with a large diameter body tube which was especially intended for micro-photography and stand III with a body tube of normal diameter. This stand III C has a plain circular stage, covered with ebonite, it can be centred and rotate. Below the stage a simple Abbe type condenser with an iris diaphragm and a flat and concave mirror in a bracket. There is a triple objective changer.
With the microscope goes one Huygenian eyepiece ‘Carl Zeiss No. 2’, with a focal length of 43.97 mm, its magnification is 5.69×. There is one incomplete objective lens Zeiss, type AA, this was not investigated further. The other objective lens is signed ‘Winkel Zeiss / Göttingen’, type ‘5’, serial number 33824. It was investigated using the Bleeker microscope and a 5× Huygenian eyepiece. Its focal length is 5.40 mm, its magnification is 164×, the numerical aperture is 0.6 and the resolving power is below 1 µm. The quality of this objective is very good, it resolves the diatom Stauroneis phoenicenteron into dots (according to Van Zuylen ‘sublime’).