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A mysterious field microscope - the Chinese TWX-1 (I)

All of us know that the internet does in fact help enormously in order to look beyond the national fence. A few decades ago the networking scenario was dramatically different. Thus microscopy amateurs from the United States, Europe and other countries had a modest information exchange at best. For example German microscopy amateurs complained that "good quality field microscopes" apparently were unavailable. In 1981 the German Peter Hofmann (see literature) published a review featuring the SWIFT M51 field microscope. As a conclusion he stated [translation by us] : "It is surprising that such an ingenious instrument has not been available before". Remember that this was in the before-web-era. It was terribly difficult at this time to screen the world's market for special products like those field microscopes. So many ingenious products simply remained hidden behind national and cultural borderlines.

In 1997 the reknowned biology veteran Bill Amos reveiled the existence of the "Nikon Model H" field microsope  to the world audience. In his MICSCAPE web article he made clear that this fine Japanese field microscope had been available for a few cosmopolitan people since about 1960.

Besides, German post-war microscopists were surprised to learn about the same time that the German Hensoldt company had produced pre-war luxury field microscopes as well.

About the year 2000 international microscope collectors communicated intensively via internet. Michael Dingley from Australia offered a CD dedicated to portable microscopes only, listing many field microscopes and illustrating them with photographs. In this stage of advanced international transparency everybody thought that the history of field microscopes was closed - nothing to add. Casual reappearences of instrument designs like the "Lensman" under the labels of "Trekker" or "Readiview", plus a few MacArthur or SWIFT microscope re-makes were notified by the now much more international microscopists' community, but without great surprise.

Nevertheless one of those collectors, Manuel del Cerro, opened the door to a strange miracle by stating in his collection CD:

"Surprisingly, in the late 1980s, when the Chinese microscope-making industry was not fully developed it was already producing a very elaborate McArthur microscope."

But alas there are no illustrations on this CD, just the text hint. Today we know that Manuel del Cerro referred to the instrument depicted below which we will discuss in detail in the issues to come:

[ TWX-1 military field microscope ]

The Chinese military field microscope TWX-1, assumed to be a product by the "TaiYuan Optical Instruments Factory" in the Chinese Shanxi province. Designed for mobile military use. Apparently just stored, never actively used. Production time at least, possibly also beyond the time range between 1971 and 1979. The production years of individual instruments can be deducted from the serial numbers, all of which are "yynnnn" with yy indicating the year.

The TWX-1 can serve as an excellent mobile tardigrade research instrument as well. The following image and capture might serve as a first overview:

[ TWX-1 military field microscope ]
01Metal bulb housing  11Fine focus wheel (on both sides)
02Concave mirror, movable  12Specimen table support
03Iris diaphragma and blue filter  13Table movement guide ("y")
04Condenser, fixed height, N.A. 1.2  14Specimen wheel holder ("x")
053 objektives 10x, 45x, Oil 90x  15Battery compartment position
06Position of prism 1 (inside)  16Second eye-piece (inside)
07Position of prism 2 (inside)  17Two AA batteries (inside)
08Position of prism 3 (inside)  18Ground plate with rubber feet
09Eye-piece, thread-fixed  19Lamp access window (underside)
10Coarse focus wheel  20Light on/off

And, of course, the most important question: how about the tardigrade-specific qualities? The answer is quite simple. We love it. As a first example we are going to show the egg of the tardigrade Ramazzottius oberhaeuseri just photographed free-hands through the eye-piece of the TWX-1:

[ Egg of the tardigrade Ramazzottius oberhaeuseri ]

Egg deposited by the tardigrade Ramazzottius oberhaeuseri, diameter close to 60 µm, photographed through the eye-piece of the TWX-1 without any adapter. Camera: Sony DSC-P200. Microscope objektive: 45x / N.A. 0.63.

In the next issues we will discuss the excellent light source and light guidance of the TWX-1. Besides, the bulb can be easily exchanged against a modern LED bulb with identical thread. Furthermore we will demonstrate the optical quality by means of diatom test specimens. Last but not least we will illustrate the excellent mechanical solid metal build quality of the TWX-1 field microscope.


Peter Hoffmann: Ein Mikroskop für Untersuchungen im Feld.
MIKROKOSMOS 70 (1981) p. 336-340.
[Annotation: the Swift M51 field microscope appears to have been sold in the anglo-saxon countries as Swift FM-31].

© Text, images and video clips by  Martin Mach  (webmaster@baertierchen.de).
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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