Cosmos
A rather mysterious little machine, manufactured by the Carl Walther Waffenfabrik in Zella-Mehlis (next to the Mercedes Büromaschinen Werke), for the firm Cosmos, in Berlin. Right next to the future Checkpoint Charlie, not much is left from the 1920's Berlin at this address either... and Zella-Mehlis has not yet been photographed for Google streetview!
The machine is in all aspects identical to the machines branded Walther and Melitta, and it has a Walther trademark stamped into the base plate. It seems, in the last few years before coming to me, to have lost its wooden baseplate, which is still present in the pictures on rechenmaschinen-illustrated.
An interesting feature of the machine is the "space bar" which automatically tabs the carriage to the left one place at a time for division, operated by a spring.