Norrenberg polariscope c. 1890-1910 Max Kohl A. G. Chemnitz Germany Nicol prism, stone base (perhaps serpentine), brass, glass, steel Used to examine materials in polarized light 16” high and the base is 5-3/4” in diameter This polariscope was used for examining crystals, quartz, mica, optical glass and other materials in polarized light to measure the polarization of light waves as they passed through the various materials, and it was also used to determine the crystals’ elements of construction. There is a rotatable Nicol prism sitting in a 360° graduated circle. The uprights hold three swing away condenser lenses and one piece of clear tilting glass. There is a removable adjustable dark mirror that sits in the upper graduated circle when the Nicol prism assembly is removed. 

The polariscope is 16” high, the diameter of the base is 5-3/4” and the mirror in the base is 2-3/4” in diameter. Halfway up the steel uprights there is a 3” in diameter swing away circle engraved in degrees surrounding a 2” gimbaled specimen plate. The instrument is in good condition. There is spotting on the steel uprights and some loss of the original lacquer. “Max Kohl A.G. Chemnitz” is engraved in the base. A fellow collector Daniel Kile who specializes in petrographic microscopes and the study of minerals suggested the base material is serpentine. German, Circa 1890 - 1910 Max Kohl was founded in 1876 by Max Hans Robert Kohl. They grew to perhaps the largest providers worldwide of scientific instruments in the period from 1890 to 1930. Their customers included teaching institutions of all types including high schools, colleges and universities. Many scientific laboratories also used their products. They had the largest product range of any instrument manufacturer which was over 4,000 different instruments and other scientific related items. They published a series of scientific instrument catalogs which were up to 1,000 pages long with pictures, descriptions and prices of their instruments. Today in addition to their instruments the catalogs are highly sought after by collectors and are excellent reference sources for instrument identification and applications. The Max Kohl factory was destroyed during World War II and they ceased all operations.