The lituus is a species
of the Archimedean spiral.
Some authors add (-r, φ) forming a double shape.
The curve is formed by the loci of a point P moving in such a way that the area of a
circular sector remains constant.
*Roger Cotès *(1682-1716) was the first to study the curve. Appointed
professor at Cambridge at the age of 24 his work was published only after his
death.
*Maclaurin* gave the curve its name in his book 'Harmonia Mensurarum' (1722)
using the resemblance of the curve to a crosier ^{1)}.
The inverse of the curve is Fermat's spiral.
**notes**
1) lituus (Lat.) = bend, crook.
In the old Roman empire the lituus was a crosier. |