Wilhelm Schickard

Wilhelm Schickard (22 April 1592 – 24 October 1635) was a German polymath who drew a calculating machine in 1623, twenty years before Pascal's calculator was invented. A fire destroyed the first machine, as it was being built by a professional in 1624, and Schickard abandonned his project.

It was reintroduced to the world in 1957 by Dr. Franz Hammer as a precursor to Pascal's calculator.[1] The building of the first replicas showed that Schickard's machine had an unfinished design and therefore wheels and springs were added to make them usable.[2] The use of these replicas demonstrated that the single tooth wheel, when used within Shickard's design, was an inadequate carry mechanism.[3] Schickard's work had no impact on the development of mechanical calculators[4] (see Pascal versus Schickard).

Contents

Life

Schickard was born in Herrenberg and educated at the University of Tübingen, receiving his first degree, B.A. in 1609 and M.A. in 1611. He studied theology and oriental languages at Tübingen until 1613. In 1613 he became a Lutheran minister continuing his work with the church until 1619 when he was appointed professor of Hebrew at the University of Tübingen.

Schickard was a universal scientist and taught biblical languages such as Aramaic as well as Hebrew at Tübingen. In 1631 he was appointed professor of astronomy at the University of Tübingen. His research was broad and included astronomy, mathematics and surveying. He invented many machines such as one for calculating astronomical dates and one for Hebrew grammar. He made significant advances in mapmaking, producing maps that were far more accurate than previously available.[5]

He was, among his other skills, a renowned wood and copperplate engraver.[5]

Wilhelm Schickard died of the bubonic plague in Tübingen, on 23 or 24 October 1635.[5] In 1651, Giovanni Riccioli named the lunar crater Schickard after him.

Political theory

In 1625 Schickard, a Christian Hebraist, published an influential treatise, Mishpat ha-melek, Jus regium Hebraeorum (Title in both Hebrew and Latin: The King's Law) in which he uses the Talmud and rabbinical literature to analyze ancient Hebrew political theory.[6] Schickard argues that the Bible supports monarchy.[7]

Calculating machine

In 1623 and 1624, Schickard drew what he called a Speeding Clock or Calculating Clock on two letters that he wrote to Johannes Kepler and explained that the machine could be used for calculating astronomical tables. The machine could add and subtract six-digit numbers, and indicated an overflow of this capacity by ringing a bell; to add more complex calculations, a set of Napier's bones were mounted on it. Schickard's letters mention that the original machine was destroyed in a fire while still incomplete.

Incidentally, Kepler used another one of Napier's inventions for his calculations (much more appropriate for computing planets' orbits than his Napier's bones): the logarithm tables; Because of this, Kepler dedicated his Ephemeris to John Napier.[8]

In 1957, Dr. Franz Hammer, an expert in Johannes Kepler's work, challenged the fact that Pascal had invented the mechanical calculator by announcing to the world that the drawings of a previously unknown calculating clock, predating Pascal's work by twenty years, had been found in these two letters.

Dr. von Freytag Loringhoff, a mathematics professor at the University of Tübingen built the first replica of Schickard's machine in 1961 but he had to improve on the design of the carry mechanism:

This simple-looking device actually presents a host of problems to anyone attempting to construct an adding machine based on this principle. The major problem is caused by the fact that the single tooth must enter into the teeth of the intermediate wheel, rotate it 36 degrees (one tenth of a revolution), and exit from the teeth, all while only rotating 36 degrees itself. The most elementary solution to this problem consists of the intermediate wheel being, in effect, two different gears, one with long and one with short teeth together with a spring-loaded detente (much like the pointer used on the big wheel of the gambling game generally known as Crown and Anchor) which would allow the gears to stop only in specific locations. It is not known if Schickard used this mechanism, but it certainly works well on the reproductions constructed by von Freytag Loringhoff.
—Michael R. Williams[2], History of Computing Technology, IEEE (1997)

Without this twentieth century improvement in the carry mechanism, with wheels and springs which are not described in any of Schickard's letters or drawings, the replicas would not have worked. Another problem was found after the replicas were built:

... it is almost certain that Pascal would not have known of Schickard's machine ...
Pascal seems to have realized right from the start that the single-tooth gear, like that used by Schickard, would not do for a general carry mechanism. The single-tooth gear works fine if the carry is only going to be propagated a few places but, if the carry has to be propagated several places along the accumulator, the force needed to operate the machine would be of such magnitude that it would do damage to the delicate gear works.
—Michael R. Williams[3], History of Computing Technology, IEEE (1997)

Schickard's machine used clock wheels which were made stronger, and were therefore heavier, to prevent them from being damaged by the force of an operator input. Each digit used a display wheel, an input wheel and an intermediate wheel. During a carry transfer all these wheels meshed with the wheels of the digit receiving the carry. The cumulative inertia of all these wheels could "...potentially damage the machine if a carry needed to be propagated through the digits, for example like adding 1 to a number like 9,999".[9]

Even though Schickard designed his machine twenty years earlier, Pascal is still the inventor of the mechanical calculator because the drawings of Schickard's calculating clock described a machine that was neither complete nor fully usable.

The Institute for Computer Science at the University of Tübingen is called the Wilhelm-Schickard-Institut für Informatik in his honor.

Notes and references

  1. ^ Jean Marguin p. 48 (1994)
  2. ^ a b Michael Williams, p.122 (1997)
  3. ^ a b Michael Williams, p.124,128 (1997)
  4. ^ René Taton, p. 81 (1969)
  5. ^ a b c History of Computing Foundation. "Wilhelm Schickard entry at The History of Computing Project". http://www.thocp.net/biographies/schickard_wilhelm.html. Retrieved 2007-07-19. 
  6. ^ Eric M. Nelson, "Talmudical Commonwealthsmen and the Rise of Republican Exclusivism, The Historical Journal, 50, 4 (2007), p. 826
  7. ^ Eric M. Nelson, "Talmudical Commonwealthsmen and the Rise of Republican Exclusivism, The Historical Journal, 50, 4 (2007), p. 827
  8. ^ Lynne Gladstone-Millar; p. 44 (2003)
  9. ^ Eric Swedin, p.11 (2005)

Sources

  • Williams, Michael R. (1997). History of Computing Technology. Los Alamitos, California: IEEE Computer Society. ISBN 0-8186-7739-2. 
  • Marguin, Jean (1994) (in fr). Histoire des instruments et machines à calculer, trois siècles de mécanique pensante 1642-1942. Hermann. ISBN 978-2705661663. 
  • Ginsburg, Jekuthiel (2003). Scripta Mathematica (Septembre 1932-Juin 1933). Kessinger Publishing, LLC. ISBN 978-0766138353. 
  • Gladstone-Millar, Lynne (2003). John Napier: Logarithm John. National Museums Of Scotland. ISBN 978-1901663709. 
  • Swedin, Eric G.; Ferro, David L. (2005). Computers: The Life Story of a Technology. Greenwood. ISBN 978-0313331497. 
  • Taton, René (1969) (in fr). Histoire du calcul. Que sais-je ? n° 198. Presses universitaires de France. 

External links