"If any figure can be given to a Solid, the Spherical is the easi­est of all others, as it is likewise the most simple, and holdeth the same place amongst solid figures, as the Circle holdeth amongst the superficial. The description of which Circle, as being more ea­sie than all the rest, hath alone been judged by Mathematicians worthy to be put amongst the postulata belonging to the descri­ption of all other figures."