E. Hartnack was a hard-working disciple of his famous and well-known uncle George Oberhaeuser from 1857 and took control of his company in 1860, introducing improvements and innovations but keeping the form of his models. With the Franco-Prussian War of 1870, he moved to Potsdam, Germany, leaving an associate, Prazmowski in Paris. Freud used a microscope from this same manufacturer in his studies on the nerve cells of the brain. (http://www.microscopy-uk.org.uk/mag/indexmag.html?http://www.microscopy-uk.org.uk/mag/artoct06/mc-freud.html).
Perfectly preserved instrument, of excellent quality, built by Edmund Hartnack (1826-1891) around 1875 in Paris. It belongs to the “Continental” style and has the number 21075 engraved on the case. The whole set is housed in a magnificent mahogany box, beautifully constructed and perfectly preserved, retaining its original lock and key. This microscope has all the components that made the Continental style triumph and that was definitively imposed in the last quarter of a century throughout Europe and the USA, such as the shape of its foot, its compact size or its micrometric focusing system. With a height of about 30cm, the macrometric approach is made by moving the main tube. The mirror is double sided, flat and concave and under the observation deck there is a fixture to limit the light projected on the observations. A small box lined with blue velvet houses 3 of these limiters as well as 3 targets in mint condition. The optics are completed with 2 other objectives, one of them housed in its original brass container from the same manufacturer, as well as 2 eyepieces. Completing the set are a dual lens turret, a signature Hartnack light concentrator mounted on the main tube, and a camera lucida made while working with his uncle and signed by them both. The microscope preserves the lacquer in perfect condition, so it has hardly been used.
References: "Billings Microscope Collection" pag 219, fig. 432
H. Moe, "The Story of the Microscopes", pag 193