The Mercedes Euklid 29 is a manually driven, full keyboard calculator which has automatic division. The keyboard has 7 columns of keys. There is a carriage with a 12-digit register, and a 6-digit counter.
The crank on the right is angled towards the front. It can only be turned clockwise. There are two switches to the left of the keyboard. One selects whether a turn of the crank will perform an addition or a subtraction. The other selects whether the counter is incremented or decremented. To the right of the keyboard is a black button which clears the input from the keyboard. Normally this button is marked L for Löschen, but on my machine the button is blank. The othe button is marked Add, and when it is pushed down and locked in place, the keyboard will be automatically cleared after every turn of the crank. The button on the left marked Div selects automatic division, and that is explained in more detail later.
The principle of proportional levers is unique to the Mercedes Euklid series of calculators. The basic version used in the first models used sliders for inputting a number, one for each digit. These would shift a gear along its axle, but instead of engaging with a stepped drum, it engaged with one of ten parallel toothed racks shared by all the input digits. These toothed racks are pivoted to an arm, and when one end of that arm swings out, the racks move different amounts, varying from 0 to 9 units. The register wheels move in one direction only, so when the arm has moved back and the racks have returned to their starting position then the input has been added to the register. For subtraction the other end of the arm is moved so that complementary digits are added.
When a keyboard was used for input instead of sliders, each axle was given five gears that can slide along it, normally resting in a position inbetween two of the racks. When a key is pressed, one of the gears moves slightly up or down to engage with a rack. In this way only one gear is active at any one time, and only a small movement is needed to make it active.
The serial number of my machine is 48967, which means it was made in about 1941. The serial number can be found on various places on the mechanism, but from the the outside can only be seen on the underside of the carriage when it is shifted to the right.
Below is a video I made that demonstrates the Mercedes Euklid model 29.
In this video I show the proportional lever mechanism in action.
Christel Hamann (1870-1946) was a highly prolific and inventive designer of calculating machines. He founded his own company in 1896, at which his first machines were made. The full range of his lesser known early work is somewhat unclear. It is possible that he started with troncet adders and pinwheel machines, as his name has been linked to the Trick (troncet adder) and the Berolina (pinwheel machine) due to some of his patents. His first proper machine design was called the Gauss, and was a cylindrical machine with a single stepped drum at the centre and number wheels arranged around it. He patented this in 1902. This principle had been used by Philipp Matthäus Hahn in the 1770s to make a handful of machines, but the Gauss was simpler, and maybe about a thousand were made. The culmination of the principle was the Curta calculator from 1946 by Curt Herzstark.
In 1904 hamann made a prototype calculator called the Gauss 4. It looked like a standard Arithmometer type of machine with sliders. However, instead of each slider moving a gear that engages with its own stepped drum, in this machine the stepped drums were replaced by a single ridged plate that was like an unrolled stepped drum, and when the crank was turned this plate was pulled past all the input gears. By 1905 this had developed further into an entirely new principle, proportional levers. Now in place of the ridged plate there were a set of ten parallel toothed racks, again shared by all the input digits. These toothed racks are pivoted to an arm, and when one end of that arm swings out, the racks move different amounts, varying from 0 to 9 units. The register wheels move in one direction only, so when the racks have returned to their starting position the input has been added to the register. For subtraction the other end of the arm is moved so that complementary digits are added. Hamann called this machine the Euklid.
In 1907 Hamann's company became part of Mercedes Büromaschinen-Werke. This small company had been founded only the year before by Gustav Metz and made typewriters, and presumably wanted to expand into making calculators as well. They made a few dozen Mercedes Gauss machines as well as similar amounts of the Mercedes Plus which was an adding machine that Hamann designed, but it was mainly the Mercedes-Euklid machines that became successful and were developed further. The company grew and moved from Berlin to Mehlis (now Zella-Mehlis) in Thüringen, which is where Walther were also based. By the time of the first world war, 8 models had been produced. Development and production were affected by the war, and in about 1922 Hamann left the company and moved back to Berlin to join Deutsche Telephonwerke GmbH.
Many more Mercedes-Euklid models were developed in subsequent years, all based on the same principle. When Germany was split up after the second world war the company was in East Germany, where it was allowed to grow, though it soon was producing its machines only for the Eastern Bloc countries. The casing of the machines was changed from green to light grey, and the letter R was added to the model designations. In about 1963 Mercedes became Cellatron, and the machines were rebranded accordingly. Mercedes and then Cellatron produced about 10,000 calculators per year until either 1969 or 1975 (sources disagree on the end date). In 1977 the company became part of the state-owned Robotron Elektronik, and in 1990 this was split up into smaller companies that were bought up by various others after the Iron Curtain had fallen.
The Mercedes-Euklid models are generally split into four series. Below is a table listing most of the models.
Model: Model number.
Years: Years of production. Sources are often contradictory, for example model 8 is sometimes placed as 1918 and model 29 as 1936, while adverts show them in existence in 1915 and 1934 respectively.
Capacity: Number of digits in the input×counter×result registers.
Elec.: N means manually driven, Y means electrically driven.
Keyb.: N means input via sliders, Y means input via keyboard.
Stor.: N means no extra register, T means it has an extra totaliser register, M means it has a memory storage register.
Div.: N means no special division capabilities, S means it has stop division, F means fully automatic division.
Mult.: N means no special multiplication capabilities, S means semi-automatic, K means it has multiplication keys, F means fully automatic multiplication.
|2||1911||8/10×||8×||13||N||N||N||S||N||Only a handful were made.|
|3||1912||7×||6×||13||N||N||N||N||N||Dubbed "Copernicus". Only a handful were made.|
|29||1934-1953||7/9×||6×||12||N||Y||N||F||N||The only manual machine after series I.|
Mercedes used consecutive serial numbers, shared by all their calculators except for the Trick troncet adder. So not only were these numbers used for the Mercedes Euklid, but also for the few dozen Gauss and Mercedes Plus machines, and for the approximately 4000 Mercedes A adding listing machines made between 1938 and 1945. These numbers can therefore be used to fairly accurately date when the machine was made, but not how many there are of each model. Below is a list of years and the final serial number reached in that year. After 1943 the numbers are based on very rough production estimates, so I have rounded the serial numbers to the nearest 1000 to avoid the appearance of accuracy. There is so much uncertainty that one source even claims that there is a large gap where the serial numbers jumped to 100,000. It is also unclear whether production stopped around 1969 or 1975.
This is a flyer that promotes the models 7 to 12. It is in French, has a stamp from a Belgian retailer, and probably dates from 1925 or 1926.
Here an extract from Modern Instruments and Methods Of Calculation, a Handbook Of the Napier Tercentenary Exhibition, from 1915.:
Here is the entry in Ernst Martin's 1925 book Die Rechenmaschinen:
Here are a few other small articles from newspapers and magazines.
Lastly, here are some advertisements. The first one is for the Gauss, before Mercedes got involved.
|Patent||Filing date||Published date||Name||Description|
|DE 88,223||11-06-1895||10-09-1896||Christel Hamann||Planimeter|
|US 703,785||02-07-1900||01-07-1902||Christel Hamann||Gauss predecessor|
|US 705,838||28-03-1902||29-07-1902||Christel Hamann||Extra register for pinwheel calculator|
|US 772,935||13-10-1903||25-10-1904||Christel Hamann||Pinwheel calculator improvements|
|DE 179,246||26-11-1904||30-11-1906||Christel Hamann||Subtraction using complements on pinwheel calculator|
|DE 194,527||23-03-1905||06-02-1908||Christel Hamann||Gauss calculator
See also: US 832,666
|DE 209,817||31-05-1906||13-05-1909||Mercedes Bureau-Maschinen-Gesellschaft m.b.H.||Euklid calculator
See also: US 1,011,617
|DE 210,524||30-10-1907||03-06-1909||Mercedes Bureau-Maschinen-Gesellschaft m.b.H.||Mercedes Plus adding machine|
|DE 210,661||11-02-1908||07-06-1909||Ch. Hamann, Math. Mech. Institut, G.m.b.H.||Subtraction mode on Gauss calculator|
|DE 228,563||04-06-1909||12-11-1910||Ch. Hamann, Math. Mech. Institut, G.m.b.H.||Calculator for products of more than two factors|
|DE 234,984||15-09-1910||29-05-1911||Ch. Hamann, Math. Mech. Institut, G.m.b.H.||Calculation device for trigonometric functions|
|DE 242,665||13-04-1911||16-01-1912||Mercedes Bureau-Maschinen-Gesellschaft m.b.H.||Trick, troncet with sliding cover for subtraction|
|DE 253,525||24-06-1911||13-11-1912||Ch. Hamann, Math. Mech. Institut, G.m.b.H.||Printing mechanism|
|US 1,221,318||20-04-1912||03-04-1917||Ch. Hamann, Math. Mech. Institut, G.m.b.H.||Calculator with fast multiplication|
|DE 268,729||12-04-1913||27-12-1913||Mercedes Bureau-Maschinen-Gesellschaft m.b.H.||Trick, version for British currency|
|DE 278,680||12-04-1913||02-10-1914||Ch. Hamann, Math. Mech. Institut, G.m.b.H.||Calculator with totaliser|
|DE 287,770||17-02-1914||05-10-1915||Ch. Hamann, Math. Mech. Institut, G.m.b.H.||Euklid with automatic multiplication and division
See also: US 1,566,961
|US 1,528,018||17-01-1921||03-03-1925||Mercedes Bureau-Maschinen- und Waffenwerke||Combined typewriting and counting machine|
|US 1,566,962||01-06-1923||22-12-1925||Mercedes Bureau-Maschinen- und Waffenwerke||Calculator with fast multiplication|
Rechnerlexikon has a page about
Mercedes, with links to various models, also
a history of Mercedes-Euklid, and
some material about
Rechenmaschinen-Illustrated has a page about the Mercedes Euklid, and also tables of models and production years. Note however that several models appear in adverts some years before what is shown in these tables.
The history of Computing has a biography page for Christel Hamann
Cris Vandevelde has a Model 1 and a Model 29
Christian Hamann has a Mercedes-Euklid model 22, model 29, and a model 38MS.
Wolf-G Blümich has a page about the Gauss 4 prototype, and a more in depth article.
Mathematisches Maschinenmuseum has a page about the history of Mercedes-Euklid models.
The National Museum of American History has in its collection a model 1, a model 8, a model 12, and a model 38MS.
zella-mehlis-geschichte.de has a page about the history of Mercedes company.
© Copyright 2019 Jaap Scherphuis, mechcalc a t jaapsch d o t net.