Weight, rope and roller: why unequal diameters foil the motion
Pulley and windlass studies, with a memo for a lime-free plaster
The recto gathers numbered studies (92-97) of weights hung from cords running over rollers and pulleys, together with two hand-cranked winch mechanisms sketched along the foot of the page. In the central note Leonardo argues that a roller whose two ends differ in thickness cannot work, because the thick part travels farther than the thin part where the rope rests, so the weight would have to outrun the cord that lifts it, which is impossible. A short craft memorandum at the lower left records how to make a stucco-like material without lime by kneading it with grease. The remaining inscriptions are figure labels marking the individual diagrams.
On this page
Why a roller with unequal ends makes the motion impossible
Because the rod on which the rope a b rests is much thinner than the part n m on which the weight rests, one whole turn of the roller carries the thick part farther than the thin part. The weight would then have to travel more than the rope that lifts it, yet it can rise only as much as the rope pulls. Leonardo concludes the arrangement is impossible.
How much does the line n o support of weight 4?
A caption beneath the central pulley figures poses the working question of the study: how much load the line n o carries of the weight 4. It frames the numbered diagrams above and beside it as a set of loaded cord-and-pulley cases.
Recipe for a plaster made without lime
A brief technical memorandum explains how to make a stucco-like material without lime: take lard and knead or mangle it, as shown. It reads as a practical reminder set apart from the surrounding mechanics.