# CIRCUMGYRATION

, is the whirling motion of any body about a centre; as of the planets about the sun, &c.

CIRCUM POLAR *Stars,* are those stars which,
by reason of their vicinity to the pole, move round
it, without setting.

CIRCUMSCRIBED *Figure,* is a figure which is
drawn about another, so that all its sides or planes
touch the latter or inscribed figure.

The area and perimeter of every polygon that can be circumscribed about a circle, are greater than those of the circle; and the area and perimeter of every inscribed polygon, are less than those of the circle; but they approach always nearer to equality as the number of sides is more. And on these principles Archimedes, and some other authors since his time, attempted the quadrature of the circle; which is nothing else, in effect, but the measuring the area or capacity of a circle.

Circumscribed *Hyperbola,* is one of Newton's hyperbolas
of the 2d order, that cuts its asymptotes, and
contains the parts cut off within its own space.