Wilhelm Schickard invented the mechanical calculator 400 years ago
University of Tübingen scientist corresponded with astronomer Johannes Kepler – his invention fell into obscurity during the Thirty Years’ War
A letter from Tübingen universal scientist Wilhelm Schickard to the famous astronomer Johannes Kepler on September 20, 1623, documents the invention of the first mechanical calculator: “Moreover, I have recently attempted the same by mechanical means as you have done mathematically, and constructed a machine consisting of eleven complete and six modified small wheels.” With delicate lines, Schickard sketched the design of his invention.
Using up to six-digit figures, the construction could undertake all types of basic calculation: addition, subtraction, multiplication and division. Its greatest feature however was the automatic carrying of tens, at which point a small bell apparently rang as the last digit changed from 9 to 0. Schickard was now able to calculate the movements of heavenly bodies faster and more easily than was possible manually.
The central element of the mechanical calculator was an adding machine with six cogwheels which could be used to set numbers from 0 to 9. This added up if rotated clockwise, while turning anticlockwise subtracted. For multiplication, Schickard integrated a system reminiscent of the calculating rods of Scottish scholar John Napier, and combined them with the cogs of the mechanical adder, which defined the multiplier. The numbers simply had to be set and the results could be read out – the machine did the actual calculating.
The Tübingen calculating machine was closely related chronologically to the revolution in natural sciences at the start of the 17th century. The work of astronomers Tycho Brahe, Galileo Galilei and Johannes Kepler had shown that natural phenomena – such as the movement of the planets – could be precisely predicted through observation, measurement and calculation. The sciences were also being taken seriously and promoted in political circles, with many at that time believing that the future could also be foretold from the positions of heavenly bodies. However, the mathematical challenges were increasing with the ever more complex calculations involved in the still-young sciences. Yet undertaking calculations with large numbers is prone to mistakes. “In particular when adding long series of numbers, Schickard’s calculating machine could have been a great relief, as it could help to avoid miscalculations,” explains Tübingen computer scientist, Professor Herbert Klaeren.
“Schickard’s construction contains the core elements of computer science,” says Professor Oliver Bringmann, speaker of the Department of Computer Science at the University of Tübingen. “It defines calculation rules and applies them in an automated process.” Calculating machines with greater capacity were not built until the 18th century.
Constructing the machine and experimenting with it accompanied Schickard’s work at the University of Tübingen. In 1619 the theologian was appointed Professor of Hebrew and other biblical languages. He developed a study aid for his students consisting of rotating stacked discs with Hebraic verbs and endings to enable them to learn the complicated conjugations more easily. Even Isaac Newton had one. In 1631 Schickard was appointed to the Chair of Astronomy, Mathematics and Geodesics as the successor to astronomer and mathematician Michael Mästlin. Using a hand-held planetarium of his own invention, he showed the movements of the sun, the earth and the moon, and a conical star chart simplified identification of the constellations. As a school warden, he inspected Latin schools in Württemberg and surveyed the state while on his travels. From this data he drew far more precise maps than had previously been possible.
Johannes Kepler, who like Schickard studied at the University of Tübingen, became aware of his younger colleague as early as 1617. Kepler clearly recognized young Schickard’s powerful intellect and passion for mathematics at this time, and encouraged him to study science. From then on, Kepler and Schickard corresponded, and they met up again when Kepler returned to Württemberg in 1620 to assist his mother who was on trial for witchcraft. The astronomer valued Schickard’s skills as a craftsman and an artist, and engaged him to make copperplates and woodcuts for his revolutionary work “Harmonice mundi”, in which Kepler formulated the laws of planetary movements. Schickard for his part knew how much time Kepler spent calculating planetary orbits, and wanted to make the task easier for his friend.
Presentation of 20 euro commemorative coin and stamp
So Schickard commissioned the construction of a “calculating clock”, as he called it, by the craftsman-mechanic Johann Pfister, who built one model for Schickard in 1623 and later a second model intended for Kepler. However, Kepler’s model was destroyed by a fire in Pfister’s workshop.
Schickard’s life had a tragic end. In the early days of the Thirty Years’ War, the City of Tübingen escaped destruction by paying huge amounts of money. Yet once the battle of Nördlingen was lost in 1634, imperial troops were quartered in Tübingen and brought the plague with them. First, it took Schickard’s wife and three daughters. Schickard himself fell ill, but recovered. In October 1635 he caught the plague again, and this time died, just one day before his nine year old son.
Following the death of Schickard and his family in the Black Death, the knowledge of his calculating machine and Schickard’s own model were lost in the chaos of the Thirty Years’ War. Erroneously, historians credited the French philosopher Blaise Pascal with inventing the first mechanical calculator, some twenty years later. Much later, Schickard’s sketches resurfaced, and after the Second World War the machine was reconstructed at the University of Tübingen thereby proving its effectiveness. In 1960 it was presented in public. Today, there are replicas in the computer collection of the University of Tübingen and the Tübingen city museum, among other places.
On September 14, 2023, the University of Tübingen will be celebrating the 400th anniversary of Schickard’s invention with a ceremony in the Neue Aula. At the event, the Federal Ministry of Finance together with the University will showcase a 20 euro commemorative coin and an 85 cent commemorative stamp in honor of Wilhelm Schickard and his invention. Afterward, the University of Tübingen’s Department of Computer Science will be holding a symposium on the theme “From the mechanical calculator to quantum computing”.
Wissenschaftlicher Ansprechpartner:
Prof. Herbert Klaeren
Universität Tübingen
Tel. +49 7071 61 07 83
klaeren@uni-tuebingen.de
Die semantisch ähnlichsten Pressemitteilungen im idw
