Trench Periscope with Revolver 10x - 15x, C.P. Goerz Berlin, about 1914

Grabenperiskop or Trench Periscope with 10x - 15x42 revolver eyepieces, produced by C.P. Goerz Berlin, about 1914, for the Imperial German Army or Kaiserreichsheer. Important period photos demonstrate, given its effectiveness and ease of use, its use also by Kaiserliche Marine.
This trench periscope was conceived and built by C.P. Goerz at the beginning of the First World War, with the aim of simplifying and making the observation from the trenches safer than the more complicated and less manageable double scissor telescopes (Scherenfernrohre). Although it was not equipped with reticles for surveys, it proved to be very practical and efficient even for long-distance observation as, consisting of a single tube but equipped with a "revolver" with two eyepieces, one of 10x and the other of 15x easily selectable, by rotating it horizontally to the chosen position and automatically locking at each respective magnification.
Furthermore, its height of 71 cm, allowed the observer to carry out his risky task with greater safety, at least remaining protected from snipers.
Three different versions of this model are known which are different in length.
Its aesthetic condition is excellent, it is fully functional in all its parts and the detachable rain cover, the eyepiece covers and the original leather lens covers are present.
The vision is clear with both eyepieces, the weight is 2.5 kg.

C.P. Goerz was a company that built optical and photographic instruments, founded in Berlin in 1886 by Carl Paul Goerz (1854-1923), together with Carl Moser, an optical researcher, and Ottomar Anschutz, a laboratory technician in close friendships; precisely from this last C.P. In 1889, Goerz had purchased the patent for the construction of the first shutter for cameras capable of shutter speeds of 1/1000 of a second.

The company specialized in the production of lenses, cameras, telescopes and binoculars, including for military use. In 1886 it had around 25 employees, which rose to 2500 in 1911, although at its maximum expansion the workforce reached 10,000 employees.

In terms of size it was not even second to Zeiss (which in the same period had 1000 fewer workers), and it exported to many countries, including Russia and the United States. In 1905 Goerz American Optical continued to operate independently in the United States until 1972. In 1908 Goerz Photochemisches Werk GmbH was founded in Berlin, this section of the Goerz group produced film for photography and cinema.

Goerz had a fundamental relationship with the armies of the time and military supplies. In fact, it remained famous both for the large trench binoculars (First World War) and for the binoculars supplied to all the weapons of the Austrian-German Army (including navy and air force) as well as Bulgaria, Romania etc. Even today there are countless examples of Goerz binoculars that have value on the war and optical antiques market, one must think that in 1906 Goerz had already produced and exceeded 100,000 "Triëder" model binoculars, both for civil and military use.

In addition to the main and historic factory in Friedenau (Berlin), C.P. Goerz was also present in London, Paris and Vienna, Bratislava, Milan, Riga and St. Petersburg. Other sections were dedicated to chemical products and also for typewriters or calculating machines, which a division of the company was responsible for producing until 1945.

In 1910 the company bought the "Sendlinger Optische Galswerke" company founded by J. Von Fraunhofer and C. A. Steinheil for the production of optical glass and mirrors, which made it completely independent from purchasing from other retailers. After the First World War, with the Treaty of Versailles, the German companies that had produced war material were slowed down in production and this quickly led to a serious economic situation.

In 1923 Paul Goerz died and the company, which was in bankruptcy, was purchased by Zeiss which, together with the companies "Contessa", "Nettel", "ICA" and "Ernemann" founded Zeiss Ikon in 1926. The American division of Goertz became an independent company under the name Goertz American Optical Co. producing camera lenses and continuing their technical development. In 1971 it was bought by Kollmorgen, which was absorbed by Schneider Optics in 1972.