Weights of movers: balance beams and falling bodies
Loaded balance-arm diagrams with a rebuttal on air resistance and a table of straight and curved motion
A mechanics sheet arranged in four columns of small balance-beam (asta) diagrams, each loaded with numbered weights and captioned by cases: joined and disjoined movers of double weight, equal weight with double descent, and double leverage. Below, a polemical paragraph rebukes an opponent who claimed that two weights in sesquialteral (3:2) proportion, dropped from equal height, would fall in double proportion, arguing he wrongly discounted the air's resistance under which the weights had been established. The lower half sets out a classification of motion between mover and moved as straight or curved, simple or compound, illustrated by the horse pulling a boat.
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Weights of joined movers of double weight
The first column heads a set of balance-beam figures: weights of joined movers, taken to be of double weight, with the arms labelled by numbers such as 2 1 and 4 1.
Balance arm of double leverage
A pair of beams labelled 2 1; 2 1 illustrates a weight of double leverage carried by an equal weight of movers, isolating how arm length trades against load on the balance.
Falling weights and the resistance of the air
Addressing an opponent, Leonardo denies that two weights of sesquialteral proportion dropped from equal height fall in double proportion. The error, he says, was to discount the air's resistance, forgetting that the weights making that proportion were established over the air's resistance when weighed.
Classes of straight and curved motion
A table pairs the motion of mover and moved as straight or circular, simple or compound: straight mover with circular moved, circular with straight, and the horse pulling the boat as an example of straight mover and moved. Compound cases combine straight and curved in sequence.