J.D.MÖLLER´S PREPARED SLIDES REDISCOVERED

   
   

 

In 1864, JOHN DIEDRICH MÖLLER (1844 - 1907) founded the J.D.MÖLLER company in Wedel near Hamburg. This company sold among other things microscopic slides. J.D.MÖLLER had specialized on arranging diatoms on coverslips. Even today such slides are produced by some amateurs, but MÖLLER was able to arrange thousands of frustules with an accuracy never reached again. Depending on the purpose he produced prepared slides showing linear arrangements, circular arrangements and even show preparations with diatoms arranged in regular geometric patterns. So J.D.MÖLLER became a legend among professionals: Never again slides with so many diatoms have been made (some with more than 4000 different diatoms!), never again such a precision combined with such an aesthetic has been attained.

J.D.MÖLLER described and photographically documented many of his prepared slides in a catalogue published in 1890, but all these magnificently prepared slides were lost, and as MÖLLER never published his method in detail he took his secrets to his grave. Usually a coverslip is coated with a very thin layer of special adhesive, then the frustules are positioned with the help of a very fine bristle, but this technique does not allow any readjustment and cannot explain the accuracy of positioning attained by MÖLLER.

In 2002 Mr.M.BURBA, a member of the MIKROBIOLOGISCHE VEREINGUNG, started investigations concerning the fate of these preparations. Time consuming researches in various archives and museums led to the rediscovery of a variety of MÖLLER´S preparations and even of the positioning device MÖLLER used, along with MÖLLER´S laboratory diaries. Based on this evidence the technique used could be largely reconstructed. And even the whereabouts of the largest ever produced slide with more than 4000 species laid on an area of 5x7mm could be determined.

SHOW PREPARATIONS

During the 19th century it became fashionable in bourgeois circles to organize meetings of "interesting contemporaries" (artists, philosophers, scientists). This was done by the lady of the house. She could improve her social status this way, and at the same time she gained some liberty by practicing activities being met with social approval. But a meeting of that kind was not only a place for discussions: "exotic rarities" were demonstrated including so-called "show-preparations" - artfully arranged slides that showed either attractive geometric patterns (see above) or even pictures composed of diatoms, wing scales of butterflies and small hard parts of marine animals. The diameter of these works of art were less than 1 to 2 mm and so they were inspected with special low magnifying microscopes every item diplaying beautiful interference colours.The prices of these slides were significant: A German catalogue of 1880 states prices of 400 up to 800 Mark (for comparison: in 1913 the price of a house plus piece of land was about 6000 Mark). Today the most beautiful examples achieve fancy prices up to EUR 24.000!

Another popular type of slides, not shown here, were photographs of landscapes, art objects or newspaper pages, reduced to 2x2 mm by using a very special grainless sensitized material. These products are the precursors of the "Microdot process" which was used later to smuggle intelligence material.

When tracing the fate of the MOELLER slides Mr. M. BURBA also spotted some of these show preparations. Usually the objects were mounted with Canada balsam mixed with monobromnaphthalene to increase the refractive index. The gradual evaporation of this liquid despite the presence of a thick ring of varnish often resulted in the shrinkage of the mountant, but Mr. BURBA managed to restore these preparations. We show here some particularly fine examples (all the colours displayed are interference colours which vanish when inspected at higher magnification).

 
       
 
       
 
       
   
       

In 2007 an exhibition about J.D.MOELLER has been on display. Here the exhibition catalogue.

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