Jacob Auch

Simplicity is the ultimate sophistication.
Leonardo da Vinci

Jacob Auch (1765-1842) was a very good German mechanic and clock-maker, who created about 1790 a calculating machine not of original construction, but of very good workmanship.

Auch was born in Echterdingen, a small town in the district of Esslingen, in Baden-Württemberg. In the same town, from 1781 till 1790 served the famous German pastor and engineer Philipp Matthäus Hahn.

The young Jacob worked six years in Hahn’s workshop in Echterdingen and proved to be his best apprentice. At some moment Auch decided to start his own business, and in 1787 he opened and worked in his workshop in Vaihingen an der Enz and Karlsruhe, where he stay until 1798, when he was hired as a Ducal Mechanic (Großherzoglichen Hofmechanicus) at the Weimar court, where he stay until his retirement in 1842.

The calculating machine of Jacob Auch (© Boerhave museum, Leiden, Netherlands)
The calculating machine of Jacob Auch (© Boerhave museum, Leiden, Netherlands)

During the years 1789 and 1790, while in Vaihingen an der Enz, Jacob Auch made several adding machines of a very good workmanship. He was obviously inspired by the adding machine of his mentor Hahn, as its construction is quite similar to the adder of Hahn, but has an improved tens-carry mechanism.

It is unknown how many machines have been produced by Auch, but at least three survived to our time—one in Württembergisches Landesmuseum in Stuttgart, dedicated to the Margrave Karl Friedrich von Baden (signed: Jacob Auch Vayhingen, see the lower images), second in Matematisch-Physikalischen Salon in Dresden, and third in Boerhaave museum (Rijksmuseum Boerhaave), Leiden, Netherlands (see the upper image).

The calculating machine of Jacob Auch (© Württembergisches Landesmuseum Stuttgart)
The calculating machine of Jacob Auch (© Württembergisches Landesmuseum Stuttgart)

The dimensions of the machine of Auch in Stuttgart are: 22,8 x 6,1 x 1,9 cm (the device in Leiden is bigger—28 x 8,0 x 4,0 cm), the weight is about 720 g. It is made mainly of brass and is placed in a wooden case.

The “Stuttgart machine” of Auch has eight digital wheels, as seven of them are decimal, and one (the second from the right) is divided to 12 parts (the Leiden device is destined for another monetary system and has a 24 parts wheel). The graduation of the disks was made according to the monetary system adopted throughout the southern states of the Holy Roman Empire in 18th century (60 Kreuzer = 1 Gulden). The two rightmost wheels are used for calculations in Kreuzer (12 x 10), others (decimal) are used for Gulden. Entering of the numbers can be done by means of a stylus.

At the lower left corner of the box is inscribed an short instruction for work in German: use black to add and red to subtract. This means, that the internal calculating mechanism is unidirectional, the wheels can be rotated only in clockwise direction, and subtraction can be done, using the method complements of 10.

Close view to the digital wheels of the machine of Jacob Auch (© Württembergisches Landesmuseum Stuttgart)
Close view to the digital wheels of the machine of Jacob Auch (© Württembergisches Landesmuseum Stuttgart)

The calculating machine of Auch has in improved tens-carry mechanism. This important constructional element of the machine used the so-called tens-carry-rail, which guarantees reliable tens-carry operations. The machine also has a memory mechanism for storing numbers.

A drawing of machine of Jacob Auch
A drawing of machine of Jacob Auch (© Arithmeum Museum, Bonn)

Biography of Jacob Auch

Jacob Auch was born on 22 February, 1765, in Echterdingen (near Stuttgart, Württemberg), to Johann Andreas Auch (1733–1787), a baker, and Christina Henn (1736–1782). Jacob had a younger brother, Johann Georg (2 Jul 1766-24 Aug 1838), who also became clock-maker and mechanic.

When Jacob turned sixteen, his father wanted to put his elder son to a trade, and initially planned for him to became a barber, but Jacob had absolutely no taste for this vocation. Fortunately, in his hometown, Echterdingen, in 1781 was appointed a new pastor – the famous German engineer Philipp Matthäus Hahn. Thus the young Jacob became an apprentice of Hahn and used to work for six years in his workshop in Echterdingen. Hahn was a severe task master, but Jacob Auch soon proved himself as the most talented and ambitious apprentice of Hahn, so in 1887 he decided to go in his own way, establishing a family and his own workshop, and he was very successful in his career as a watch-maker and mechanic.

On 11 July, 1787, in Vaihingen an der Enz, Auch married to 22 years old Eva Regina Wintermantel, a daughter of Johann Christoph Wintermantel (1738–87) and Anna Maria Wintermantel (née Roselius), and in the same year he opened his own workshop in Vaihingen. They had one (survived adulthood) child – the son Johann Jacob Auch (1789-1885). Auch stayed for more then 10 years in Vaihingen, and during this period he fulfilled many orders of the professor of mathematics and physics from Institute of Physics in Karlsruhe Johann Lorenz Böckmann.

A pocket chronometer, made by Jacob Auch for Seeberg observatory
A pocket chronometer, made by Jacob Auch for Seeberg Observatory

Auch stayed in Vaihingen until 1798, when he was hired as a ducal court mechanic (Großherzoglichen Hofmechanicus) at the Weimar court, a presiguos position, which he hold until his death in 1842. As court mechanic for the Duke of Weimar he worked mainly for the new Seeberg Observatory from 1798 on. The renowned astronomer Baron Franz Xaver von Zach headed the observatory until 1806 and was one of Jacob Auch’s most important customers. Auch supplied numerous watches and instruments for the observatory, which was at the time the most modern in Europe.

The double-dial astronomical watch, made by Jacob Auch
The double-dial astronomical watch, made by Jacob Auch

Auch is well known as the author of two books for watchmaking—Taschenbuch für Uhrenbesitzer (Weimar, 1806) and Handbuch für Landuhrmacher (Weimar, 1827). The latter was published first time in 1827 and reprinted many times during the next century.

Besides his calculating machine, Auch is known as a maker of many clocks and chronometers, besides the instruments for the Seeberg Observatory (including a telescope for Johann Wolfgang von Goethe, who visited him in 1799 and 1800). Auch also created important astronomer’s pocket watches in the style of his master Philipp Hahn, with dials on both sides; they showed the traditional watch face on one side and planetaria on the other. To the present day survived a very good double-dial astronomical watch, made by Auch (see the nearby photo).

Jacob Auch died on 20 March 1842, in Weimar. He was inherited by his son, Johann Jacob Auch (1789-1885), who started from 1821 in his father’s workshop in Weimar, and began to build mainly tower clocks according to a completely new functional principle.