Monocular compound microscope - Serial No. 25627 - 1850-1900 - Germany - E. Hartnack

Antique E. Hartnack compound monocular microscope, manufactured in Potsdam, Germany, serial number 25627, preserved in its fitted wooden carrying case with three numbered eyepieces and associated historical accessories and documentation.

Edmund Hartnack was one of the most important microscope makers of the 19th century. After his earlier career in Paris, Hartnack established his workshop in Potsdam in 1870 and became particularly renowned for the quality of his optical instruments and his work on advanced microscope objectives.

Based on comparison with documented Hartnack serial numbers, this microscope can reasonably be dated to approximately 1887–1890. Hartnack instruments numbered 24312 and 24560 are documented at around 1885, while serial number 26231 is documented at around 1890. Particularly interesting is another surviving Potsdam-period Hartnack microscope, serial number 25132, which is equipped with the same sequence of eyepieces numbered 2, 3 and 4 as the present instrument. The dating given here is therefore based on comparison with surviving documented instruments rather than an exact factory production record.

The microscope is constructed principally from lacquered brass with a painted metal horseshoe-form base, square stage and adjustable mirror beneath. The maker's signature “E. Hartnack / Potsdam” is engraved on the instrument.

Three eyepieces numbered 2, 3 and 4 are included and fit into their designated compartments in the fitted case.

An especially interesting feature of the lot is the surviving two-sided paper document found with the microscope, recording part of its later Austrian history.

One side is headed:

“Optisches Institut
Ludwig MERKER's Wtw.
Johanna Merker
WIEN, XVIII.,
CZERMAKGASSE 7.”

Ludwig Merker (1856–1920) was a prominent Viennese microscope and optical-instrument manufacturer. His business moved to Czermakgasse shortly after the beginning of the 20th century and continued after his death. The reference to “Ludwig Merker's Wtw.” (Witwe / widow) and Johanna Merker therefore points to a later Austrian chapter in the history of this Hartnack microscope rather than its original manufacture.

The reverse of the same document bears the stamp:

“Dipl.-Ing. Erich Valentin
Pichlwang 42
Post Timelkam, Ob.-Öst.”

together with handwritten microscopic measurement notes including “μ = 1/1000 mm” and further mm/μ calculations. This provides an interesting connection to the microscope's later use or ownership in Upper Austria.

Also included are several associated microscope accessories and boxes of cover glasses/slides. These appear to be later additions accumulated during the working life of the instrument and are not represented as original Hartnack accessories.

IMPORTANT CONDITION NOTE:
The objective lens that would screw into the threaded lower end of the microscope tube is missing. The threaded objective mount itself is present and is clearly photographed. Because the objective is absent, the microscope has not been optically tested and is offered primarily as a historical scientific instrument and collector's object.

The microscope otherwise displays attractive age-related patina and wear consistent with its approximately 135-year history. The lacquered brass retains a particularly appealing antique appearance. There are scratches, marks, oxidation/tarnishing and areas of wear to the metal surfaces and painted base. The fitted wooden case likewise shows normal age-related scratches, marks and edge wear, while the interior fittings and textile-lined sections remain present. Please examine the photographs carefully as they form an important part of the condition description.

- Microscope dimensions:
Height: 25 cm
Width: 7 cm
Depth: 9 cm

- Fitted case:
28.5 × 15 × 10.5 cm

- Total weight including case and contents:
2.785 kg

A particularly attractive and well-documented example of a late 19th-century E. Hartnack scientific instrument, retaining its fitted case, three numbered eyepieces and unusual later Austrian provenance documentation.

The lot will be carefully packed with particular attention to securing the microscope, optical components and fitted wooden case, and shipped with tracking.