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Early mechanical calculators - Johann Christoph Schuster, 1820

Hahn's calculating machine, improved model by Johann Christoph Schuster, protégé and son-in-law of Philipp Mathius Hahn. (1795-1823)

Brass, partly gold-plated, steel, round enamel scales. Built between 1805 to 1820.

Provenance: Grimme Calculating Machine Museum, Natalis & Co AG, Braunschweig.Waldbauer Collection No. 2397 Lit.: The Braunschweig GNC monthly magazineNovember/December 1925, Braunschweig: p. 524 with illustration. Described there as follows: Hahn machine. Invention of the pastor Philip Matthäus Hahn, Echterdingen, Germany 1774. Manufactured in 1805 to1820 by the watchmaker Joseph Christian Schuster, Ansbach, who worked as a journeyman for Hahn from 1778-1780 and later married her sister.

 

Shuster's calculator was one of the last of the highly individually built and elaborately ornamented calculators of the pre-industrial era; it has 1052 parts. Calculating machines of the 17th and 18th centuries are extremely rare. There are in fact only ten calculating machines remaining from that period, which are four species, that is can perform all four basic operations of arithmetic, (addition, subtraction, multiplication and division). During the baroque age there was neither a commercial nor a scientific need for mechanical calculating machines. Tradesmen still calculated using calculation boards, tables and reckoning counters. And in the sciences, calculating methods were unknown or just beginning to be developed. Thus, the clergyman Philipp Mathaus Hahn (1739-1790), Schuster's mechanical master and brother-in-law, had built his calculating machines 'for the propagation of the Gospel'.

 

At the time they were built, these calculating machines were not used practically. They were destined for the curiosity cabinets; the 'Kunstkammer' of princes and nobility. Some, such the gloriously decorated machine by Johann Jackob Sauter could have no other purpose!

 

Schuster commenced his first calculating machine according to Hahn’s design in 1789 (probably under the supervision of Hahn), and it was completed in Uffenheim in 1792 (Hahn had died two years earlier), a twelve digit design, 10 billion capacity. From 1805 Schuster developed his own calculating machine in Ansbach (four-species machine, relay roller principle), which is also based on Hahn’s design but is more compact and easier to use. Its construction is basically the same as the first machine, but it has an improvement on the setting mechanism, where the racks are similar to Müller‘s calculating machine from 1783, and are moved using rotary knurled knobs that mesh with the rods while showing their digital values in a separate aperture. This calculator has a nine digit capacity, 100 million. It was completed in 1820. A third calculator was discovered in 1993 and was dated as being built between 1820 and 1822, it is identical to his second machine except that it has a ten digit capacity, one thousand million or one billion.

 

Johann Christoph Schuster was born on 8 October 1759 in Westheim (Middle Franconia, Bavaria, Germany). He was the son of Lorentz Schuster (died 1785), a local farmer, and Anna Elisabetha Fröhlich (died 1762). In his youth he became enraptured with watches - as a thirteen year old he is reported to have built a wooden clock, and subsequently to have repaired watches successfully. Around 1777 he was bound apprentice to Philipp Matthäus Hahn, a pastor and owner of a mechanical workshop in Kornwestheim. Schuster remained in Hahn’s workshop for two and a half years, then returned to his father’s farm, but continued his occasions with machines, keeping a connection with his mentor. In 1785 Schuster married Maria Katharina Jacobina (1759–1812), a half-sister of Hahn. They had three sons (two of them died early) and five daughters.

 

After his father’s death in 1785 Schuster took over his farm and also opened in the village a workshop in which he made clocks, sundials, earth and celestial globes, and calculating machines. From 1786 he was a freelance watchmaker, first in his native Westheim and then in Uffenheim. Schuster moved to Ansbach in 1797 and became a master member of the local watchmaker’s guild and received permission to work as a “mechanic and watchmaker” in Ansbach, Uffenheim, and Erlangen. He ran a workshop in Ansbach, the seat of Hohenzollern princes (known as margraves), and stayed there working as a mechanic and court watchmaker until his death.

Besides the above-mentioned calculators, four other masterpieces of Schuster survived to our time: two pocket watches (now in Württembergisches Landesmuseum Stuttgart and Stadtmuseum Ansbach) and two double globe astronomical clocks (in Mathematisch-Physikalischer Salon Dresden, and one in a private collection).

Johann Christoph Schuster died on 7 September 1823 in Ansbach.

The watchmaker Jacob Auch (1765-1842) was, besides Johann Christoph Schuster, the second mechanic of Philipp Matthaus Hahn that built calculating machines of his own. Three of his adding machines remain - they are in Stuttgart, Dresden and Leyden. Hahn is thought to have built four, four species calculating machines.

 

 

              

 

 

The nine digits of the setting mechanism are operated with knurled nuts, whereby the setting of a number can be checked in a control mechanism with dials. The result mechanism and the revolution counter are located in the central, rotating part of the machine, they are each ten digits. The larger enameled dials belong to the result mechanism, and the smaller ones to the revolution counter. The black and red digits in the result set are intended for multiplication and division, respectively (red digits present complementation to 9 of black digits, e.g. over black 5 is inscribed red 4).

 

This video with the use of computer aided design, shows the layout, components and function of the Schuster calculator. Video demonstration using computer animation to show the internal components as well as the functionality of the Johann Christoff Schuster calculator made in 1820. The first four species calculator capable of addition, subtraction, multiplication and division was invented by Gottfried Leibniz in 1672. From that time through the time this artifact was produced, about a dozen hand-built calculating machines were produced. Video courtesy of the Arithmeum, Bonn, Germany.

 

This video demonstrates the Hahn calculator, however, other than the way the operand in inputted (a sliding scale stick vs. the stick being operated by a numbered thumbwheel), they both operate the same way.

Internal schematic of the Hahn design. Very similar to Shuster's. 

           

Photo from the Grimme Calculating Machine Museum, Grimme, Natalis & Co AG. A section of the museum c. 1925 showing several late 17th and early 18th century calculators. photo c. 1890. The circled calculator is the example described on this page. Then acquired by the Helmut Waldbauer collection. Mr. Waldbauer was a dealer out of Vienna in typewriters and calculators and built his collection over 55 years.

The company Grimme, Natalis & Company in Braunschweig was founded in 1871 as a merger between Carl Gimme and Karl A, Nautalis, both companies were engaged in the manufacture of sewing machines. In 1892 the company purchased the rights to manufacture pinwheel calculating machines on the design of the Swede W. T. Odhner. Barrel, (pinwheel), calculating machines were smaller, lighter, cheaper to make and easier to operate than the Arithmomètre. Under the leadership of the engineer Franz Trinks, later in 1892, they began manufacturing and improving a machine called the Brunsviga. In 1927 the company changed it's name to Brunsviga, reflecting their primary activity of the manufacture of calculating machines under that trade mark name. Brunsviga entered into an agreement with Olympia Werke AG of Wilhelmshaven (part of the AEG group), in 1957 which led ultimately to the company being absorbed into Olympia in 1959.

       

First Day Cover mailed in 2022, showing one of the three calculating machines known to be made by Johann Schuster.                                        

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