Incidentally Pappus describes the thirteen other polyhedra bounded by equilateral and **equiangular** but not similar polygons, discovered by Archimedes, and finds, by a method recalling that of Archimedes, the surface and volume of a sphere.

[3] Thales discovered the theorem that the sides of **equiangular** triangles are proportional.

Tait that a similar representation of the type (30) is obtained if we replace the circle by an **equiangular** spiral described, with a constant angular velocity about the pole, in the direction of diminishing radius vector.

Again, in the **equiangular** spiral we have p =r sin a, and therefore P = u/ri, if u =hh/sinh a.

But since an **equiangular** spiral having a given pole is completely determined by a given point and a given tangent, this type of orbit is not a general one for the law of the inverse cube.

If A or B vanish we have an **equiangular** spiral, and the velocity at infinity is zero.

Where m=4(3n), except in the case 11=3, when the orbit is an **equiangular** spiral.