Weight, contact, and the rope that moves more easily coiled
Apparent motion at a distance, ground pressed by narrow supports, and the friction of rope extended or rolled
A note on the perspective of motion opens the page: two bodies moving equally but at different distances seem to move at different rates, the farther appearing slower in proportion to its distance. Leonardo then turns to weight and contact, observing that the ground yields lower under a narrow support than a broad one bearing the same load, and that a body is harder to move where it has greater contact. A hundred-pound rope, he notes, is far easier to shift when coiled than when stretched out; sketches show the ball of rope and the same rope extended to its full length, followed by a reasoning about how contact distributes a weight over the parts of its support.
On this page
Perspective of motion
Two things of equal motion at different distances appear to move differently: as many times as the distance of the first enters into that of the second, so many times the second seems slower than the first.
Narrow supports press the ground lower
The ground that sustains the supporters of weights is pressed as much lower under one thing than another as the one is narrower than the other, when both are pressed by equal weight.
Greater contact is harder to move
Where there is greater contact, the weight is more difficult to move. A hundred-pound rope, moved first extended and then rolled up, is beyond comparison easier to move when rolled up than when stretched out.
How contact distributes a weight
It is as easy to move a weight with much contact as one with little: the lesser contact concentrates the whole weight on its support so that motion is hard, while the greater contact directs as much less weight to each part as those parts are more numerous. A ball of rope and the same rope extended are drawn beside the note.