Microscope Museum

Collection of antique microscopes and other scientific instruments

Antoni van Leeuwenhoek fish viewer microscope replica, EXEMPLAR EX LONDINIO MMXXV (2025)

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 Antoni van Leeuwenhoek microscope, made in April 2025, illustrating a quite unusual and large type of microscope made by Van Leeuwenhoek. The replica is made of brass and acrylic (imitating the original glass), and contains a single 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 by Van Leeuwenhoek to observe the passage of red blood cells through the capillaries in the tails of living fish and eels, and to demonstrate such observations to his many visitors. To use this microscope, the specimen was wrapped in wet fabric and then mounted against the glass. The microscope lens plate was mounted on the other side of the glass, screwed in an arm that made it possible to move the lens in all directions on the glass surface. The dimensions and process to build and use this microscope were described in detail by Van Leeuwenhoek himself in a 1710 letter to the Royal Society of London. Two of these devices appeared to have been built by Van Leeuwenhoek, listed 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. An image of this microscope type can be identified on the cover image of the catalogue (Figure 1 – see white arrow). The same device was illustrated in a book of travels published in 1753 by Zacharias Conrad von Uffenbach, in which he described a visit he made to Van Leeuwenhoek in 1710 to see his discoveries (Figure 2). Unfortunately, no surviving microscope of this type is known to exist today. 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 3 below shows a selection of replicas of these microscopes making part of this collection.

Figure 1. Cover image of the 1747 auction catalogue when all Van Leeuwenhoek’s lenses and microscopes were sold after the death of his daughter Maria. The white arrow points to a fish viewer microscope.

Figure 2. Van Leeuwenhoek’s fish viewer microscope as illustrated in the 1753 book of travels by Zacharias Conrad von Uffenbach (Vol. III, pp. 349 – 360; publisher: Frankfurt-Leipzig: Ulm-Memmingen).

Figure 3. 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”.