Weight and the Resistance of Its Support
A load appears heavier where the support resists least, with a two-groove pulley
Leonardo argues that a weight shows itself heavier wherever it is sustained by a weaker resistance, and that the support resists least at the part most remote from its fixed point. The lower drawing is a pulley with two grooves, two concentric wheels from which three boxed weights are suspended, annotated with the string of numbers 2 2 2 2 4 2. The principle links the apparent heaviness of a load to distance from the fixed anchoring point of its support.
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A weight seems heavier where resistance is weaker
That weight shows itself to be heavier which is sustained by a weaker resistance. Where the support resists less, there the weight it bears appears heavier, and the part of a support that resists least is the part farthest from its fixed anchoring point.
The least-resisting part is farthest from the fixed point
The part of the support that resists least is the one situated most distant from its fixed point. The accompanying numbers 2 2 2 2 4 2 tally the weights distributed across the device.
Two-groove pulley carrying three weights
The lower figure shows a pulley formed of two concentric wheels or grooves. Three cords descend from it to boxed weights, illustrating how the load is shared across the grooves.