Microscope Museum

Collection of antique microscopes and other scientific instruments

 

      

Antoni van Leeuwenhoek eel viewer/showcase for visitors microscope replica, EXEMPLAR EX LONDINIO MMXXV (2025)

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Antoni van Leeuwenhoek (1632 - 1723) was a Dutch microscopist who was the first to observe bacteria and protozoa, and is many times referred to as the father of microbiology. Van Leeuwenhoek made microscopes consisting usually of a single high-quality lens of very short focal length. At the time, such simple microscopes were preferable to the compound microscope, which increased the problem of chromatic aberration. Van Leeuwenhoek’s methods of microscopy remain something of a mystery. During his lifetime he made more than 500 lenses, most of which were very small (no larger than a pinhead) and usually mounted them between two thin brass plates, riveted together. A large sample of those lenses were found to have magnifying powers in the range of 50 to, at the most, 300 times. This is a replica of an antique microscope, made in April 2025, illustrating a quite unusual eel viewer/showcase for visitors type of microscope (eventually) made by Van Leeuwenhoek. The replica is made of brass and contains a single replaceable lens enclosed within two brass plates riveted together. The replica is engraved with “EXEMPLAR EX LONDINIO MMXXV”, and with the Roman numeral “I”. This type of microscope would have been used to observe the passage of red blood cells through the capillaries in the tails of living fish and eels. To use this microscope, the specimen was placed head down in a glass tube containing water and inserted in the microscope. Lenses are easily exchanged in this instrument and focussing is made via a wing screw on the side opposite the viewer’s eye. The association of this format of eel viewer to Van Leeuwenhoek is only circumstantial, as no unambiguous description of this device appears in the 1747 auction catalogue when all Van Leeuwenhoek’s little lenses and microscopes were sold after the death of Van Leeuwenhoek’s daughter Maria, and 24 years after Van Leeuwenhoek’s death. There is also no known description or image unambiguously associating this type of microscope to Van Leeuwenhoek, in his many letters, the auction catalogue, or in any other document or publication available from many of Van Leeuwenhoek’s visitors. Still, as mentioned above, there is some circumstantial evidence indicating that Van Leeuwenhoek may have been associated with this type of eel viewer. One of these eel viewers is owned by the Museum Boerhaave in Leiden (object number V07015; Figure 1). As the story goes, this microscope was brought to the Netherlands from St. Petersburg in the 1760s by either David de Gorter the elder or his son. It is believed to be the same microscope that Van Leeuwenhoek presented to Tsar Peter the Great during the Tsar’s visit to the Netherlands in 1696 - 1697. The device was eventually donated to the Physical Cabinet at Leyden University toward the close of the 19th century and was later relocated to Museum Boerhaave. However, the claim that it originated from Van Leeuwenhoek remains doubtful. The eel watching microscope illustrated in a Van Leeuwenhoek’s own 1689 letter to the Royal Society of London differs significantly in design from this one. The instrument in question bears a closer resemblance to the eel-watchers crafted by the Van Musschenbroek workshop, which first appeared in their 1707 sales catalogue and were available until at least 1748. Van Musschenbroek’s workshop had replicated Van Leeuwenhoek’s original design but made several modifications. They added a fourth side to the frame and introduced a separate support for the lens mount. Instead of a simple screw, focusing was achieved through a screw mechanism fixed to a forked bracket, one end attached to the lens support and the other to the frame. Additionally, the instrument used a single spring to secure the glass tube. Originally, it was sold with a selection of lenses stored in a small case. Van Leeuwenhoek made and used other types of microscopes to observe and study different types of samples, including his most well-known single-lens microscope, dual- and three-lenses microscopes, and other eel/fish viewers. Figure 2 below shows a selection of replicas of these microscopes making part of this collection.

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Figure 1. Brass aquatic microscope said to be taken to the Netherlands from St Petersburg in the 1760s, which may have been presented to Tsar Peter the Great by Van Leeuwenhoek, and currently owned by Museum Boerhaave, Leiden (adapted from Bracegirdle, Brian (1983) Beads of glass: Leeuwenhoek and the early microscope. Catalogue of an Exhibition in the Museum Boerhaave).

 

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Figure 2. Replicas of different types of microscopes associated with Antoni van Leeuwenhoek: (A) Standard type of single-lens microscope; (B) Dual lenses microscope; (C) Three-lenses microscope; (D) Aquatic/eel viewer microscope; (E) Eel viewer/showcase for visitors microscope; and (F) Fish viewer microscope. All these replicas are engraved with “EXEMPLAR EX LONDINIO MMXXV”.