Of two cones of one common base is made Archimede's Rhombus, as here, whose geodæsy shall be cut of two cones.
And
15. Cylinder of equall heighth are as their bases are. 11 p xij.
Sackes in which they carry corne, are for the most part of
a cylinderlike forme. If an husbandman therefore shall lend unto his neighbour a sacke full or corne, and the base of the sacke be 4 foote over. And the neighbour afterward for that one sacke, shall pay him 4 sacke fulls, every sacke being as long as that was, yet but one foote over in the diameter, he may be thought peradventure to have repayed that which he borrowed in equall measure, to wit in heighth and base. But it shall be indeed farre otherwise: For there is a great difference betweene the quadrate of the foure severall diameters, 1. 1. 1. 1. that is 4: and 16, the quadrate of 4, the diameter of that sacke by which it was lent. For Circles are one unto another as the quadrates of their diameters are one to another, by the [2 e xv]. Therefore he payd him but one fourth part of that which he borrowed of him.
And
16 Cylinders reciprocall in base and heighth are equall. 15 p xij.