Table of the fifth proportion and quadruple ratio
Ruled segments labelled a, b, c, d, e, g paired with numeric quantities in mirror script
This small page carries one of Leonardo's proportion tables, headed 'Fifth' and noting a 'quadruple' (4:1) ratio. Ruled horizontal segments are labelled with the letters c, d, g, a, b and e and set against numbers such as 32, 24, 8 and 6, with the note 'multiples of e b'. The sheet belongs to a run of tables in which paired terms are compared as multiplex ratios, in the manner of Euclidean proportion theory. The writing is faint pencil gone over in pen.
On this page
The 'fifth' and the quadruple ratio
Under the heading 'Fifth' the page pairs quantities — 32, 24 and 8 above the letters c, d and g — and separately marks a 'quadruple' ratio with the values 6 and 2 beside the note 'multiples of e b'. The terms a, b and e anchor the lower segments, one carrying the value 8. The figures show how one magnitude stands to another as a whole-number multiple.