Magnifiers: a closer look (V)
A "Winkler & Wagner" folding magnifier - the ultimate gadget!

There are reasons why we are discussing all those magnifiers in depth: whereas publications about compound microscopes and so-called simple microscopes are available in huge quantity, literature about magnifiers appears to be scarce. But we do use magnifiers extensively in search for tardigrades. E.g., when screening dry moss samples in situ the approximate number of tardigrade inhabitants can be estimated by means of a good 10x magnifier. Ca. 80 to 120 years ago, hand magnifiers were taken much more seriously. Even a dedicated magnifiers' dictionary appeared at this time:

Fig. 1: Cover page and (only one) example page, taken from part III of Fremdsprachliches Optisches Wörterbuch - Lupen und Lesegläser (Weimar 1927). We notice with utmost respect that most exclusive technical terms like the "aplanatic Steinheil magnifier" were considered as important and selected for presentation in four languages!

Due to the lack of written sources it can be terribly difficult to tell the actual production date of a given magnifier. Moreover, many interesting items are lacking signatures or other clues to their origin. Already two years ago we had presented a folding magnifier with extremely high magnifying power but were not able to clarify its origin. In the meantime we came across a catalogue helping to understand (see literature). Here, once more a short description with text and images:

Fig. 2: Extremely tiny folding magnifier with ultra-high magnification - we measured a magnification factor of 34x! It appears to be made in the first quarter of the 20th century. Weight 13.4g. Brass housing, partially blackened, partially nickel-coated.

Fig. 3: Same as in fig. 2, upside-down detail view of the optical head.

Please note the conical housing of the optics. This geometry is the only way to achieve that daylight will properly illuminate the object under investigation. Cylindrical optical head housings will perfom much worse in this respect. It is obviously an instrument for very professional use, possibly the ultimate gadget too ;-). But at the same time it is requiring practice and a shiver-free hand. Only then you will get the full performance. This magnifier is rendering an absolutely crisp view with an enorous amount of detail. Though the lenses are uncoated (glass coatings didn't exist when it came into being!) the user is well protected against stray-light, as the top lens is positioned in a recessed manner, moreover surrounded by black grooves. When comparing with present-day products it will become clear that those ingenious refinements are no more used, even in the most luxurious hand magnifiers. Instead you will find chrome-loaded lens environments, primitive screw ring mounts, cylindrical fittings, poor finish etc. pp. Funny enough the internet is even providing positive "user reviews" about 30x magnifiers with 35 mm lens diameters (but of course those specs do not make any physical sense!).

Fig. 4: Same as fig. 3, view of the optical system. This is a true cemented Steinheil triplet system with an outer diameter of 5 mm. When mounted it is viewed through an iris opening of 3 mm diameter. Also the sides of the glass cylinder are blackened - signaling a perfect product.

Fig. 5: Photograph of the year number on a German 1 Cent coin (with a letter height of 0.65 mm), taken through the magnifier. The field of view is still rather wide, measuring ca. 5 mm. Though the user's pupil will come very, very close to the lens in this situation and the edges are definitely out of focus this wide field will help to find your visual detail target more easily.

Fig. 6: Enhanced detail of fig. 5. Scratches and other flaws on the numbers are already coming out. Object width shown ca. 2.5 mm.

Just for comparison we are showing the performance of a much bigger professional instrument, namely the so-called "Leitz Großfeld-Stereomikroskop":

Fig. 7: For comparison, the same object as in fig. 5, photographed through a very good stereo microscope of the 1970s. In this case a 4x objective and a 16x eyepiece were used (cf. the respective instrument description in our February issue).

Of course the "Winkler&Wagner" hand magnifer cannot provide the same detail as the heavy, stationary Leitz Großfeld-Stereomikroskop but even today it is well able to mark top notch quality within the field of hand magnifiers.

Literature

Fa. Winkler & Wagner: Katalog 9 über naturwissenschaftliche Hilfsmittel. p. 34/35. Wien 1913.
[Annotation: "Winkler&Wagner" is the name of the seller, not the manufacturer. We think that the manufacturer was in fact a very small company, too modest to place its name on the instrument.]

© Text, images and video clips by  Martin Mach  (webmaster@baertierchen.de).
The Water Bear web base is a licensed and revised version of the German language monthly magazine  Bärtierchen-Journal . Style and grammar amendments by native speakers are warmly welcomed.

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