CONE

In Geometry, a solid body, having a circle for its base, and terminating in a point, which is called its vertex. The cone may be described as follows—: Suppose a fixed point A without the plane of the circle BCD, and through the point A let a straight line A B indefinitely produced on both sides be drawn, and carried round the circumference of the circle BCD; the two surfaces ABC D and Abed generated by this motion are the surfaces of two opposite or vertical rones. The circle B C I) is called the base of the con", and the straight line A O drawn finm its vertex to the centre of the [s. 285]