Finding the Centre of Gravity of Seven Suspended Weights
A balance problem: locate the common centre of gravity of seven known weights at unknown spacings.
Two diagrams of horizontal rods hung from an overhead beam, each carrying seven boxed weights labelled with numbers, frame a short problem statement in mirror-script. Leonardo proposes to hang seven weights of various known quantities at unknown distances from one another and to find exactly the center of gravity of the whole sum. The upper rod is marked with a graduated scale and the hanging points are lettered a through f; the lower rod repeats the array of seven weights. Marginal figure labels ('2a', 'pa') tie the sketches to a sequence of experiments.
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Locating the common centre of gravity
Leonardo sets the task of hanging seven weights of various known quantities, at distances unknown from one another, and finding exactly the center of gravity of their whole sum. The horizontal rods in the diagrams carry the seven weights as boxed numbers suspended by cords, with the hanging points along the upper rod lettered a, b, c, d, e, f. The graduated scale on the beam serves to measure out the balancing distances.
Known weights, unknown distances
The rows of numbers beside the rods (such as 2 1 3 4 2 3 1) record the magnitudes of the seven weights hung along each beam. Because the weights are known but their spacings are not, the problem is one of resolving the balance arithmetically to fix the center. The lettered points a through f mark the positions whose distances must be determined.