In 1642, at the age of 19 years, Blaise Pascal built a mechanical calculating machine for addition and subtraction. For a long time it was thought to be the first calculating machine with a mechanical tens-carry mechanism. It was not until the middle of the 20th century that it was discovered that in 1623, the year Pascal was born, Wilhelm Schickard, mathematics professor in Tübingen, had built a mechanical calculating machine to help him as well as his friend Johannes Kepler with their calculations. It had six places with mechanical tens-carry mechanisms for both addition and subtraction. Thus, the fame of priority is due to Schickard, whose machines were unfortunately lost during the Thirty Years’ War. The fortuitous discovery of his letters and sketches to Kepler in the observatory at Pulkova established his invention. This, however, in no way lessens the great achievements of Pascal. His machines were more elegant and of more delicate construction, and his novel “gravity-feed” tens-carry mechanisms worked perfectly for all six places. But Pascal, who just wanted to simplify his father’s work as chief royal tax commissioner in Normandy, was not particularly gratified. To him it was nothing but a machine to replace tedious and error-prone mental arithmetic. He would much rather have continued his philosophical and theological studies. But his machine was such a groundbreaking step forward that Chancellor Séguier, his father’s supervisor, rewarded him with a royal privilege, the forerunner of later patents. This led to the design and building of several Pascalines. In the literature about fifty machines are mentioned. Today, only nine Pascal machines remain. In 2013 another Pascaline appeared on the international market. But a careful inspection revealed that it was actually a very well made replica. At first it was thought to be another replica built by the watchmaker Ernest Rognon who was commissioned in 1926 by CNAM, Paris, to construct three replicas. One was for the Science Museum, London, another for the IBM Collection, and the third was for a private client. They were built extremely meticulously and their exterior was like the original. Thus, they looked like originals at first glance. A detailed comparison of the machine of 2013 with the one from the Science Museum, London, revealed, however, that it was not a Rognon machine.
In detail, the interior mechanisms of the Pascaline are much more like the original in their filigree delicateness and functional design. A dedication on the cover describes the machine as an exact copy of the machine built for Queen Christina of Sweden, which is now in CNAM. Alongside this valuable replica, there is an enlarged replica of the Pascaline which was built in 2010 for the visitors of the Arithmeum to use, so that they can experience and understand this fascinating machine which comprises such an important step forward in the development of mechanical calculators.