Windlasses, rope-drums and the pressure in a bag
Windlass and rope-drum studies, ending with the uniform pressure felt through a pressed bag
Folio 169r continues the study of windlasses and rope-drums (subio) with numerous sketches of cranked drums, pulleys, hanging weights and a coiled spring. Leonardo notes that although windlass a b gathers less cord than a n, both raise their weight equally high in one full turn, and that a weight rising along a more oblique line moves more easily. He observes that among equal-length cords wound on a drum the thicker gives fewer turns, the cord farther from the center winding up soonest and lifting the load least. A final remark beside a circular figure labelled baga states that every part of the bag equally feels the weight pressing it.
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Windlasses a b and a n raise equal weight per turn
Although the windlass a b gathers less cord than the windlass a n, in one complete turn it raises its weight m from the ground just as high as the other raises its own, that is n.
Oblique ascent is easier
The more a weight rises along a more oblique line, the easier its movement. Alongside, the question is posed of in which part of the drum the motion will be more difficult.
Thicker rope on a drum gives fewer turns
Among cords of equal length wound upon a drum, the thicker gives fewer turns; the cord whose center lies farther from where it is gathered winds up sooner and raises or lifts the thing pulled a shorter way.
Uniform pressure within a pressed bag
Every part of the bag (baga) equally feels the weight that presses it, a remark on how pressure distributes through a filled sack.