5. The greatest periphery in a sphericall surface is that which cutteth it into two equall parts.
Those things which were before spoken of a circle, the same almost are hither to bee referred. The greatest periphery of a sphericall doth answere unto the Diameter of a Circle.
Therefore
6. That periphery that is neerer to the greatest, is greater than that which is farther off: And on each
side those two which are equally distant from the greatest, are equall.
The very like unto those which are taught at the [15], [16], [17], [18. e. xv]. may here againe be repeated: As here.
7 The plaine made of the greatest periphery and his diameter is the sphericall.
So the plaine made of the diameter 14. and of 44. the greatest periphery, which is 616. is the sphericall surface. So before the content of a circle was measured by a rectangle both of the halfe diameter, and periphery. But here, by the whole periphery and whole diameter, there is made a rectangle for the measure of the sphericall, foure times so great as was that other: Because by the [1 e vj]. like plaines (such as here are conceived to be made of both halfe the diameter, and halfe the periphery, and both of the whole diameter and whole periphery) are in a doubled reason of their homologall sides.