Holdrian comma: Difference between revisions

BudjarnLambeth (talk | contribs)
mNo edit summary
m Rewrite the ratio; +category; -see also that's already incorporated in the body text
Line 1: Line 1:
{{Infobox Interval
{{Infobox Interval
| Ratio = 53root(2)
| Ratio = 2^{1/53}
| Cents = 22.6415
| Cents = 22.6415
| Name = Holdrian comma, Holder’s comma, Arabian comma, 1 step of 53edo
| Name = Holdrian comma, Holder’s comma, Arabian comma, 1 step of 53edo
Line 21: Line 21:
Holder 1731 writes that [[Marin Mersenne]] had calculated 58<sup>1</sup>/<sub>4</sub>s in the octave; Mercator "working by the logarithms, finds out but 55, and a little more."<ref name=Holder-1731/>
Holder 1731 writes that [[Marin Mersenne]] had calculated 58<sup>1</sup>/<sub>4</sub>s in the octave; Mercator "working by the logarithms, finds out but 55, and a little more."<ref name=Holder-1731/>


One of these intervals was first described by [[Jing Fang]] in 45 BCE.<ref name=Touma/> Mercator applied logarithms to determine that <math>\ \sqrt[55]{2\;}\ </math> (≈ 21.8182 cents) was nearly equivalent to a syntonic comma of ≈ 21.5063 cents (a feature of the [[historical temperaments|prevalent]] [[meantone]] temperament]] of the time). He also considered that an "artificial comma" of <math>\ \sqrt[53]{2\;}\ </math> might be useful, because 31 octaves could be practically approximated by a cycle of 53 [[just fifth]]s.  
One of these intervals was first described by [[Jing Fang]] in 45 BCE.<ref name=Touma/> Mercator applied logarithms to determine that <math>\ \sqrt[55]{2\;}\ </math> (≈ 21.8182 cents) was nearly equivalent to a syntonic comma of ≈ 21.5063 cents (a feature of the [[historical temperaments|prevalent]] [[meantone]] temperament of the time). He also considered that an "artificial comma" of <math>\ \sqrt[53]{2\;}\ </math> might be useful, because 31 octaves could be practically approximated by a cycle of 53 [[just fifth]]s.  


William Holder, for whom the ''Holdrian'' comma is named, favored this latter unit because the intervals of [[53edo]] are closer to [[just intonation]] than to [[55edo]]. Thus Mercator's comma and the Holdrian comma are two distinct but nearly equal intervals.
William Holder, for whom the ''Holdrian'' comma is named, favored this latter unit because the intervals of [[53edo]] are closer to [[just intonation]] than to [[55edo]]. Thus Mercator's comma and the Holdrian comma are two distinct but nearly equal intervals.
Line 30: Line 30:
== See also ==
== See also ==
* [[Mercator's comma]]
* [[Mercator's comma]]
* [[Syntonic comma]]
* [[53edo]]
* [[Historical temperaments]]
* [[Historical temperaments]]


== Notes ==
== Notes ==


[[Category:53edo]]
[[Category:Small commas]]
[[Category:Small commas]]
[[Category:Commas named after individuals]]
[[Category:Commas named after individuals]]