Lot n° 401
Estimation :
800 - 1200
EUR
Result without fees
Result
: 1 400EUR
HARTNACK & PRAZMOWSKI
Nice heliostat developed... - Lot 401 - Lynda Trouvé
HARTNACK & PRAZMOWSKI
Nice heliostat developed by Hartnack and Prazmowski in its mahogany veneer box containing the accessories (two mirrors and a sundial). The dial is signed "HARTNACK & PRAZMOWSKI 1 RUE BONAPARTE PARIS".
A heliostat aims to make the sun seem stationary by a set of clock and mirrors. They are precise and fragile instruments, but complex to set up. This model is designed for experiments and research requiring stationary rays in the field of optics or photography of microscopic objects.
The "new heliostat" of Hartnack and Prazmowski is simpler and less expensive than the existing models. Its principle is "simple" with a clockwork movement rotating (with a speed of one revolution of 48 hours) an axis on which is placed a square mirror which will be in rotation.
The dial bears the hours spaced of 10 minutes between each graduation and is enamelled.
The clockwork is specific to this device with an escapement with anchor. A small dial is divided into 60 minutes to check the regularity of the movement. As for a watch, a button allows to wind up the mechanism.
When the object is set up, the solar clock allows to adjust the inclination of the movement (which varies according to the seasons)
When the instrument is oriented, we place the rectangular mirror that will rotate to create a horizontal light beam immobile. The second plane mirror on a heavy stand with a ball joint allows to direct the light beam in the room in order to carry out the experiments.
The apparatus is designed for latitudes ranging from 0 to 70.
The book "Précis de microphotographie" by G. Huberson of 1879 describes precisely this type of heliostat Hartnack & Prazmowski (with an engraving page 59).
The house of Hartnack and Prazmowski is known for the quality of its work and mainly for its microscopes (used by the great scientists like Pasteur). In 1830 Georg Oberhaeuser founded his company in Paris specialized in scientific instruments.
He quickly established himself in Place Dauphine and collaborated with various scientists before joining forces with Edmund Hartnack in 1855 and the company moved from 19 to 21 Place Dauphine. Four years later Hartnack bought the company and in 1870 left Paris for Potsdam with the Franco-Prussian war.
On his return in 1873 he joined forces with Adam Prazmowski and set up shop at 1 rue Bonaparte.
Five years later, Prazmowski bought out the sign which became Prazmowski, then in 1883 "Bézu, Hausser et Cie" when it was transferred to two former employees, but the name Prazmowski lasted until his death in 1885. Then, the company was bought by Nachet around 1896.
Thus this model of heliostat, created in 1873 will last until the 1910's under various names (Hartnack & Prazmowski, Prazmowski, Bézu Hausser et Cie, and Nachet) which can be found in catalogs and publications such as the "Journal de Botanique" of 1887 or in the 1898 Nachet catalog.
Nachet stopped the production of the Hartnack & Prazmowski heliostat around 1910.
Our model bears the signature "Hartnack & Prazmowski", is thus one of the oldest known to date and dates from 1873-1878.
The device is in perfect condition, except for an oxidation on the main mirror and on the bottom of the secondary mirror.
Dimensions : 20 cm high for the secondary mirror, 15 cm high for the device
Dimensions of the box : 27,5 x 18 x 12 cm
Different heliostats of this type, but later exist under the signature Nachet or Prazmowski in the collections of the observatory of Nice, of the high school Janson-de-Sailly in Paris, ...
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