Magnifying glass, Botany or Phytology, F.lli Koristka Milan given to Prof. Giovanni Negri, circa 1925

Botany or Phytology magnifying glass, produced by F.lli Koristka Milano, donated by the company to Professor Giovanni Negri, presumably in conjunction with his election as Director of the "Giardino dei Semplici", a prestigious Florentine botanical institute as well as a museum of natural history and vegetable garden botanist from the University of Florence, which took place in 1925.

History of Koristka:

Francesco Koristka, of Polish origin (Silesian to be precise), after having worked in Vienna and being Salmoiraghi's assistant, set up his own business and founded it in Milan in 1881 (1880 is reported almost everywhere but in an old Koristka advertisement I found clearly written: F. Koristka S.A. (House founded in 1881) a company, Ottica Meccanica Flli. Koristka. It soon became one of the most important and appreciated producers of optical instruments (binoculars and microscopes), standing out for the high quality of the lenses mounted on their products.

During the First World War it produced binoculars intended for officers of the Royal Navy: the "Marenostrum". It also became the most important company in Italy for the construction of microscopes and one of the few Italian precision industries that exported both to Europe and America.

Thanks to his relationships with Ernst Abbe (1840-1905), Koristka had the opportunity to build microscopes and photographic lenses by exploiting the patents of the Zeiss company in the same way as Krauss worked in Paris, but he also built lenses with original designs such as the telephoto lens Negri-Koristka, and subsequently the Ars, the Sideran, the Sagittal, the Meridian and the Proximar telephoto lens. In 1929 the F.lli Koristka company was absorbed by Officine Galileo Firenze, but continued to produce under its own brands for a few decades.