- Arithmetic rope
[
Allegory of the Arithmetic with knotted rope (taken from theHortus deliciarum (around1180 )] The arithmetic rope, or knotted rope, was a widely-usedarithmetic tool in theMiddle Ages that could be used to solve manymathematical and geometrical problems.An arithmetic rope generally has at least 13 knots—therefore, it is often called thirteen-knot-rope—placed at equal intervals. More knots were beneficial, especially for
multiplication and division.In
medieval architecture , the knotted rope was indispensable for architects, because it allowed the construction of equilateral andright-angled triangle s, as well ascircle s.In the depiction of the
liberal arts inHortus deliciarum , theallegory of arithmetics is a female figure with a knotted rope.Arithmetic functions
External links
* [http://www.zdf.de/ZDFmt/mediathek/ZDFmt_video_cont/0,3498,MT-2172487--MD-1000051-vi-1-47,00.html ZDF Mediathek - Video showing the application of the arithmetic rope] ("in German")
* http://turba-delirantium.skyrocket.de/wissenschaft/rechenseil.htm ("in German")
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