Gauss-Mercedes

Cylindrical four-species stepped disc machine (1909)

The compact, cylindrical stepped disc machine with a central switching organ "in the form of an unwound stepped drum" was invented by the Berlin designer Christel Hamann around 1905 and described in patents. A precursor (the so-called Haack/Hamann design, see Bölter [2007]) was already shown at the Paris World Exhibition in 1900. The machine, first called "Gauss" and then in an improved form "Mercedes", can be regarded as a precursor of Curt Herzstark's "Curta" (cf. Inv. No. FDM 9008), because the single central stepped disc with its teeth is moved past the radially mounted gears by crank rotation, whereby the set value enters the result mechanism. Compared to the "Gauss", the "Mercedes" has a significant improvement, namely a switching disk, which is designed for complementary arithmetic (for subtraction and division). This could have been the idea generator for Herzstark's complementary stepped drum. The external characteristic of the Mercedes is the additional Add./Sub. switch next to the crank. In a detailed analysis, Ulf Hashagen [2003] goes into the interesting development process of the machine, in which geoscientists were also involved. It is said that about 1000 copies of the "Gauss" / "Mercedes" were built and offered e.g. by the Reiss company in their instrument catalogs between 1906 and 1914; only a few have survived the times. With the start of production of the Euclid 1 (FDM 6174), the production of the Gauss-Mercedes was discontinued. Cf. also inv. no. FDM 9465.