Chalmersia

Interval information

Ratio	123201/123200
Factorization	2-6 × 36 × 5-2 × 7-1 × 11-1 × 132
Monzo	[-6 6 -2 -1 -1 2⟩
Size in cents	0.01405217¢
Name	chalmersia
Color name	Lathotholurugugu comma
FJS name	[math]\displaystyle{ \text{d1}^{13,13}_{5,5,7,11} }[/math]
Special properties	square superparticular, reduced
Tenney height (log2 nd)	33.8213
Weil height (log2 max(n, d))	33.8213
Wilson height (sopfr(nd))	84
Comma size	unnoticeable
S-expressions	S351, S78 / S80
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The chalmersia is an unnoticeable 13-limit comma with a ratio of 123201/123200 and a size of approximately 0.014 ¢. Named in honor of John H. Chalmers, it is the smallest 13-limit superparticular comma. Tempering it out equates 351/350 and 352/351, thus splitting 176/175 into two, and equates 385/351 and 351/320, thus splitting 77/64 into two – these are features highly characteristic of chalmersic temperaments. In addition, it equates a stack consisting of a 729/512 tritone plus a 169/128 grave fourth with a stack consisting of a 25/16 augmented fifth plus a 77/64 minor third.

Etymology

The chalmersia was named by Gene Ward Smith in 2003 after John Chalmers.

The remarkable 123201/123200 might be named the chalmersia, since John Chalmers is presumably the first to see it.

—Gene Ward Smith, Nameable 13-limit.

See also

• Unnoticeable comma
• List of superparticular intervals