Pulley-block loads and drawing the figure's ages
How weight divides among pulley cords, with painting notes on age and muscles
This leaf interleaves two of Notebook E's recurring themes, marked by a small double-pulley diagram in the right margin. Under "Pittura" Leonardo urges the painter to depict a person through every age from birth to decrepitude, describing how the limbs and joints change and grow fat or lean. The mechanical passages, headed "Del peso e corde delle taglie," argue that the pulley cord nearest the motor feels most of the motor's excess power, that the weight divides equally among the supporting cords, and, returning to painting, that the artist must show which muscles and cords appear or hide as each limb moves.
On this page
Draw a figure through every age of life
Leonardo tells the painter to portray a person from birth to decrepitude through all the degrees of age: infancy, childhood, adolescence, and youth. In each he is to describe the changes of the limbs and joints, and which parts grow fat or lean. It extends the study of the moving, changing body across a whole lifetime.
The cord nearest the motor bears most of its excess power
Leonardo states that the pulley cord nearest its motor feels more weight from the motor's excess than the last cord, in proportion as it is swifter than that last one. This weight is not the load raised but the power of the motor's excess. He then affirms that the weight always divides in equal portion among the cords that support it.
The double pulley: weight of 4 shared by two cords
The marginal double-pulley figure is labelled a b f, 2 2, c e g, d. Leonardo notes that the weight of 4 is divided between the two cords a c and b e. The upper pulley-block, however, feels additional weight equal to the motor's power that exceeds the share each cord carries.
The windlass cord counts as a separate load
In the main column Leonardo repeats that the weight parts in equal portion among the cords of the pulley-blocks that sustain it. Included in that count is the cord joined to the motor, that is, the one joined to the windlass, because to it belongs a separate weight. That separate weight is the weight of the motor resisting the descent of the load.
Show which muscles and cords move with the limbs
Returning to painting, Leonardo instructs the artist to describe which muscles and cords are uncovered, hidden, or unchanged by the various movements of each limb. He calls this action most important and most necessary for painters and sculptors who profess to be masters. It ties the mechanics of the body to its depiction.