Vol. I: I. Prolegomena and General Introduction to the Book on Painting: 8.
The Da Vinci Notebooks
The order of your book must proceed on this plan: first simple beams, then (those) supported from below, then suspended in part, then wholly [suspended]. Then beams as supporting other weights 5 .
13:5 : 4. Leonardo's notes on Mechanics are extraordinarily numerous; but, for the reasons assigned in my introduction, they have not been included in the present work.