**The history of Christian Hamann **

Mr. C. Hamann (1870-1948) born in Hammelwarden, near Oldenburg, Germany, is known for his outstanding designs of a number of products of which three are most famous:

**Gauss**a circular calculator based on the Stepped Drum technology.-
**Hamann**(Manus-automats) based on the switching-latch-wheel technology.

The production took place at**DeTeWe *1)**, Berlin. **Euclid**calculators based on the Proportional Lever technology. Please see**Hamann / Mercedes**in the menu on the left.

From the early days on: (

It seems Christel Hamann owes his interest in the mechanics and construction of calculating machines to one of his father's friends, namely the Würzburg Professor of mathematics Dr. Eduard Selling. In 1880s Selling devised a calculating machine of very original construction, and the young Christel was allowed to take part in the building of this peculiar calculating machine. This collaboration with Prof. Selling must be regarded as crucial for the later life of Hamann.

Obviously from his youth Hamann demonstrated an extreme talent and energy in mechanics. As a teenager he attended a local Nautical Technical school in Bremerhaven, working at the same time as a mechanic in Nautischen Institute at W. Rudolph in Bremerhaven. Then he worked in Mathematisch-Mechanischen Institute von A. Ott in Kempten, in workshops of Carl Zeiss in Jena and in workshop of Carl Bamberg in Berlin. In 1896 Hamann became independent by starting his own institute in Berlin—the Mathematical-Mechanical Institute in Berlin.

Initially he dealt with the construction of geodetic and mathematical instruments, which he developed after new scientific ideas and also successfully introduced into practice and for which at the 1900 World Exhibition in Paris he was awarded the gold medal. Later Hamann devoted a part of his time in construction of textile machinery, cinematographic, medical and anthropological tools, and miniature steam engines. In the beginning of 1900s Hamann however recognized the disadvantages of fragmentation of his interests and decided to concentrate on the construction of the calculating machines.

In 1898 Hamann started to develop his first calculating machines. Initially he wanted to use the construction of Selling, which he knew perfectly, and the resulting construction was simple, but not reliable enough. Then he decided to use the stepped drum of Leibniz, developing 2 very good devices—**"Gauss"** and **"Berolina"**. Later (1902-1903) he started the design of the famous "**Mercedes Euklid**", which works with the proportional levers.

In 1909 Hamann constructed a perfect differential engine, used in the calculation of Logarithmic - Trigonometric Tables of Bauschinger and Peters.

After the WW I (1922) Mr. Hamann worked for the company Berliner DeTeWe (Deutschen Telephonwerke- und Kabelindustrie AG) in Berlin. Here he developed a new type of calculating mechanism, so called** Schaltklinke** (

Further improvements of Hamann were electric drive models, "Hamann, automatic Z, Y and X". The "Hamann Automat V" worked first time with an automatic truncated multiplication. The "Hamann Selecta" was equipped with two full keypads, the new multiplication has already allowed during operation of the machine. Hamann's other inventions include the improved computing machines "Hamann Selecta", "Hamann Elma" and "Hamann Delta", as "Hamann Selecta" has two full keyboards, allowing new multiplications to be performed during ongoing work steps of the machine.

In 1933 Hamann was appointed as a honorary doctor of Berlin Technical University.

Christel Hamann died on 9th of June, 1948, in Berlin.

In 1958 DeTeWE calculator division: "Hamann GmbH" was sold to the USA manufacturer Marchant *2) Calculator Machine in Oakland Ca.

In 1958
Smith-Corona Co bought Marchant on their turn, and form the new name SCM Smith Corona Marchant, which is labelled on the 400, 500 and 600 machine families.

Production at Hamann GmbH continued until the nineteen seventies and ended dramatically with the 600 = 1630 type.

Notes

*1)

DeTeWe was started on 11 Mai 1887 by Robert Stock in Berlin-Kreutzberg, Germany.

*2) A few items on Marchant:

In 1918, employee Carl Friden designed a new model in response to patent challenges. It was a great success, and Friden became the chief designer until he left in 1934 to found his own company.

Marchant is known for their fast calculators. Electrical motors made 1300 cycles/Min, twice as fast as the competition. They used the proportional gear technology (??) A nine is fastest and a one is the slowest ??? (have to study this in more detail!