In 1727, the Viennese court optician and mathematician Anton Braun (1686-1728) built a large circular and magnificent calculating machine as a masterpiece for Emperor Charles VI, which we had the pleasure of presenting to you here a few months ago. Braun also produced a second, much smaller circular machine. It is not known when he started building it. The question of the extent to which Philippe Vayringe (1684-1746), a clockmaker and mechanic from Lorraine, was involved in the invention or realization of the machine has also not yet been answered.
The calculating machine works with a central adapting segment that is moved around the central axis when the crank is turned. The tens are transferred by individual teeth on intermediate shafts, which mesh with the receiving gear of the next higher digit at a transition from 9 to 0. Due to the power transmission at the gear wheels, the machine can lock if there are more than three consecutive secondary tens transfers.
Even if the transfer of tens does not yet work perfectly across all digits, this idea of storing numbers with a single central element was very well thought out and was used again in a similar form in the 20th century, for example in a famous calculating machine called the Curta - although here the central element was a stepped drum.

The authentic replica in the Arithmeum was built between 1986 and 1996 at the Villingen-Schwenningen School of Precision Engineering together with two other specimens. One of them is in the local history museum in Möhringen near Tuttlingen. The second went to the German Museum in Munich as a functional model with a Plexiglas cover. The engineer Mr. Klaus Badur in Hanover also rebuilt the machine true to the original. His AutoCAD drawings served as the basis for the 3D animation video of this “Calculating Machine of the Month”, which was created by computer science student Eileen Duong using Blender software as part of her bachelor's thesis for the “History of Mechanical Computing” lecture series with Professor Dr. Ina Prinz. The video provides a detailed insight into the mechanics and functionality of Anton Braun's calculating machine.

We hope you enjoy it!