Four beams balancing their weights; a screw of varied thread
Pen and red chalk: a self-supporting timber arrangement and a screw study
In pen and red chalk Leonardo draws four beams set so that the thrust of their weights balances, each timber propping the others in a self-standing frame. A small stacked diagram at the lower right, marked a, shows a screw whose threads are of varied cross-section. The leaf carries only these editorial captions and a single letter as transcribed text; faint offset show-through from the facing page is also visible.
On this page
Four beams balancing the thrust of their weights
Four beams are arranged so that the thrust of their weights is balanced, each one supporting the next to form a self-standing frame. The study demonstrates how members can hold one another in equilibrium.
Screw with threads of various section (a)
A small stacked diagram at the lower right, labelled a, shows a screw whose threads are of differing cross-section.