An Over-Balancing 'Perpetual-Motion' Wheel of Weighted Boxes
27 'boxes of advantage' set around a wheel, with the reasoning of increase and resistance
The sheet works out a self-moving over-balancing wheel whose rim carries 27 'boxes of advantage' (cassette di favore) that are meant to give more turning force on one side than the other. Around a large circle divided into semicircles marked h and K, Leonardo argues that boxes farther from the centre gain leverage, and that enlarging the wheel multiplies the 'increase' (aumento) while reducing the resistance of box b. Smaller sketches at the right show a roller mechanism, a double toothed wheel with boxes staggered in two tiers, and a chute; each box is to be loaded with an ounce of lead, and columns of numbers accompany the calculation.
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A wheel f with 27 'boxes of advantage' and a large attached fly-wheel
Leonardo wants the wheel f to have a large wheel attached that adds 'increase' by the fury of its turning. The rim carries a b, 27 boxes of advantage, while m is the 1/28 part that makes the resistance; if that part could stop the motion, reducing it to a 1/100 part would make the desired effect take hold.
Semicircles h and K: leverage of boxes near versus far from the centre
Comparing the two halves, semicircle h has all its weights inward toward the centre while semicircle K has them outside and farther out, giving it advantage except at the upper part r a. He argues that doubling the circle doubles the increase a b so box b makes half the resistance, and enlarging it fourfold raises the increase over b by 3/4.
Sizing the lower balancing wheel f to the length of the boxes
The lower wheel f must have its diameter equal to the greatest length of the boxes, so that when one box has finished laying down, the next just touches wheel f. The wheel is to be balanced in this many-sided (polified) form.
Boxes staggered in two tiers on a double toothed wheel
On the small double toothed wheel the upper boxes are set in two tiers so that one does not meet the other, giving greater empty space where the boxes enter.
Each box loaded with one ounce of lead
Beside a small chute-shaped vessel Leonardo notes that each box is to hold one ounce of lead, as shown above, fixing the weight that drives the over-balancing wheel.