Cylinder-to-board conversion continued, with alternate methods
Two procedures for making a squared board of given thickness from a cylinder
This page repeats and develops the previous problem of turning a cylinder into a squared board (tavola) of a given thickness, again asking for its width. Two short methods are sketched: one derives the board's height from the square front of the cylinder, letting the width fall as it may while the length follows the cylinder; the other lays the given thickness onto the cylinder's front by the 'seventh of the first', then squares the resulting long, narrow board by the 'fifth of the first'. Several perspective diagrams show upright and reclining boards with ribbed ends and a square with an inscribed quadrant. Two captions, 'Transformation from cylinder to board' and 'Another cylinder', label diagrams whose accompanying text Leonardo left blank.
On this page
Cylinder to a squared board, width sought
Marked with labels a n - c r - b m, the problem is again to make from a cylinder a squared board at a given thickness, asking what its width should be.
Two alternate procedures for the conversion
In the first method the square front of the cylinder gives the board's height, its width taking whatever value chance allows and its length following the cylinder. In the second, the seventh of the first book lays the given thickness onto the cylinder's front, yielding a board longer than it is wide, which the fifth of the first then squares to complete the given thickness and width.