30 g of microscope please!

by Martin Mach, Germany

 
 
 

In 1886 Hermann Hager published a small booklet about microscopy1. He mentions a cheap microscope, "sufficient for domestic and naturalists' use" for 6 German Marks (see fig. 1, taken from Hager's booklet) with 50x linear magnification. The set included the microscope and furthermore a tripod style magnifying glass.


Figure 1

This type of popular microscope seems to have been manufactured in many countries and over a wide range of time. It can be found often on flea markets in Germany and probably also elsewhere. Even the most self-confident dealers seem to feel ashamed that they have to ask money for them, so you can get them quite cheaply. There are several different styles (see examples in fig. 2). The body of the left instrument measures 9 cm in height and has a diameter of about 3 cm. The weights of the instruments in fig. 2 are similar, about 30 g each (the left one is made of a rather thin brass plate, whereas the right one is more rigid).


Figure 2

Fig.3 explains the use of the instrument. An inbuilt spring fixes the slide in its position very close to the objective. Focusing is done by a slight movement of the objective tube within the concentric body tube and can be somewhat tedious. The optical components are concentrated in less than a cubic centimeter's volume. Some instruments have two rather primitive semi-convex glass drop lenses with the convex sides facing each other whereas more modern instruments can have regular lenses with better performance.

The combination with a magnifying glass has been continued over a long range of time. Fig. 3 with the two components taken apart, indicates that even those small microscopes can hide a further instrument - a magnifying glass - inside their body, like a Russian doll.


Figure 3

How about the optical performance? I have included a photomicrograph (fig. 4) taken through the objective of the instrument in fig . 3. to give you a rough idea. The diameter of the diatom circle is 0.75 mm. This photograph can be directly compared to the microphotograph taken through the Tami pocket microscope (fig. 5, cf. article about the Tami pocket microscope here in Micscape) of the same slide. It is quite evident that the Tami pocket microscope has a much higher overall magnification and, more important of course, a much better resolution. Nevertheless the ultralight ultrasmall cheap microscope is quite sufficient to screen coloured specimens like e.g. cross sections through plants at lower magnifications and it still easily outperforms a magnifying glass.


Figure 4


Figure 5

The more cynical people among you will think that those instruments are just a useless and outdated relic of former times and that one should not dissipate one's precious leisure time on them. But I must confess that I like those simple constructions because they are a minimalistic means to enjoy the marvel of optical magnification in a rather childish and non-professional way.

Comments to the author Comments to the author sent via our contacts page quoting page url plus : ('mmach','')">Martin Mach are welcomed.

Reference

1 Hermann Hager: Das Mikroskop und seine Anwendung. Berlin 1886. p 44.

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Published in the August 2000 edition of Micscape Magazine.

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