The Summer Solstice and the Solar Microscope

June 21, 2019

Today, which marks the summer solstice, would be a good day to experiment with what’s called a solar microscope – in fact, a kind of “magic lantern illuminated by the sun’s rays,” designed to project in a dark room a magnified image of a microscopic slide.

Works of the polymath and physician Martin Frobenius Ledermüller (1719-1769), keeper of the Margrave of Brandenburg’s natural history collection, helped to popularize microscopy in the eighteenth century, and the solar microscope – Sonnenmikroskop – demonstrated its power to a larger audience. Ledermüller’s Nachleese seiner microskopischen Gemüths- und Augen-Ergösung, “verlegt und in Kupfer gebracht von Adam Wolfgang Winterschmidt, Kupferstecher in Nürnberg” and “gedruckt auf Kosten des Verlegers von Christian de Launoy, 1762,”

Title page of Ledermüller’s Nachleese (1762). Department of Special Collections, Memorial Library, University of Wisconsin-Madison.
Engraved title for the “third fifty” observations from the same work.

featured a hand-colored engraving of the solar microscope in action, with a detailed description beginning p. 6.

Plate (Tab.) I, showing the solar microscope in action (and awaiting an audience).

This illustration comes from our copy of the work in German (call number: MS L49 G Cutter), but it also appears in Ledermüller’s Amusement microscopique, tant pour l’esprit que pour les yeux, likewise engraved and sold by A. W. Winterschmidt and printed by Christian de Launoy in Nuremberg (call number: MS L49 Cutter). A digitized version of the edition in French, from the Getty Research Institute copy, is available through the HathiTrust Digital Library; a copy at the Bibliothèque de l’Arsenal, as digitized by the Bibliothèque nationale de France, has been made available through Gallica — see, for example, view 159 in the troisième cinquaintenaire des Amusemens microscopiques.

Ledermüller — clearly not amused — referred in Nachleese to a dispute with a microscopist with the memorable name Wilhelm Friedrich von Gleichen-Russworm (1717-1783). Gleichen-Russworm, we learn from the biographical sketch by Machael E. Mitchell in the Dictionary of scientific biography, had been led to the study of microscopy by Ledermüller, but his subsequent criticisms prompted Ledermüller’s ire.

In 1781 Gleichen-Russworm in turn referred to Ledermüller in a relatively short work of 16 pages + 6 leaves of plates but with a very long title:

Des Herrn Baron von Gleichen genannt Russworm, Abhandlung vom Sonnenmikroskop: Mit dessen im Neuesten aus dem Reiche der Pflanzen, und auch in dem dritten Funfzig der Ledermüllerischen mikroskopischen Ergötzungen bekannt gemachten Universalmikroskop vereinigt, und womit sowohl im verfinsterten als hellen Zimmer, und unter freyem Himmel, wohin nur die Sonne scheinet, Beobachtungen zu machen, und die Objekte sowohl auf dem Schieber als an der Feder oder den Stift nicht nur waagrecht, sondern auch senkrecht angebracht, und beobachtet werden können: Mit sechs illuminirten Kupfertafeln (Nürnberg: In der Winterschmidtischen Kunsthandlung, 1781), call number: 1180153 noncurrent.

Gleichen-Russworm was also intrigued by processes of fertilization in plants and animals and used microscopic observations in his investigations of pollen. His work is thus linked to Pollinators, the topic of the current exhibit in Special Collections.