Pinwheel machine of Anton Braun

In 1727 Anton Braun from Möhringen on the upper Danube, mathematician and optician at the Imperial court in Vienna, presented a magnificent mechanical calculating machine to the Emperor, purportedly with the intention of supporting his application for the position of imperial instrument builder. He did, in fact, succeed, but died soon after. The six-place setting mechanism takes the form of six circular segments arranged in a circle on the top, with nine levers each (for the digits 1 to 9), which move the relevant pins radially outwards on the pinwheels below. Turning the crank adds the entered number to the result mechanism (12-place with complementary numbers shown) – the result is shown in the windows along the periphery of the cover (the silver-plated part). The setting mechanism can be rotated with respect to the result mechanism so that both multiplication and division are possible. The machine also features a single-digit revolution counter. This machine was not intended for daily use – it was intended to be exhibited and demonstrated as a prized object from the imperial cabinet of treasures and curiosities. Using the machine successfully required a great deal of knowledge with regard to its function and its inherent weaknesses. The setting levers, for example, did not have a well-defined zero position, so that by going too far one pushed the pins into the pinwheel, from where they could only be extracted by dismantling the machine with much effort. Moreover, the setting mechanism and the pinwheel mechanism had to be carefully locked in position by means of a key. Thus, Braun’s large cylindrical machine is no doubt a fascinating invention for performing all four operations of arithmetic, but it was far from perfect. The young Johann Baptist Straub (1704-1784), later to acquire fame as a rococo sculptor in Munich, designed the cover with its engravings and the feet of this machine – the playful lightness of his design was unique and groundbreaking and marked a transition from simple ornaments to artistically creative individual solutions. An exact replica of the original machine housed in the Vienna Museum of Art History was built in 2000/2001 by Ullrich Wolff together with the workshop of the engineer Iwanoff in Munich. The engravings were performed by hand by the engraver Manfred Burkert.