On 31 March 1882, Eduard Hammenstede of Cologne (Köln), Germany, received a German patent №20443 on Schnell-Addirmaschine (Quick Adding Machine). The device of Hammenstede (see the nearby patent drawing) was a column adder (to be used in adding columns of figures) with a large numeral drum and keys, arranged in two rows and as whole looks very much alike the earlier calculating machine of Thomas Hill.
The adding machine of Hammenstede looks like it has a simple and reliable construction, but it never went into production and remained only on paper. The large numeral drum was at the heart of the mechanism for doing the arithmetic.
Almost nothing is known about the inventor of this adding device. Carl Eduard Hammenstede was a German watchmaker, born in 1845 in Düsseldorf, Preußen, in the family of Heinrich Hammenstede and Anna Christiana Hammenstede (Klein). He had a younger brother, Johann Baptist (1848-1871). In 1868 Carl Eduard immigrated to Belgium, where he lived for several years, then returned to Germany and settled in Cologne.