Balance-arm diagrams: proportional weights and pulleys
Beams ruled and marked with fractions and letters, hung with weights and run over pulleys
Folio 170r is filled with diagrams for the science of the balance: horizontal beams ruled into equal segments, hung with weights and run over pulleys. Fractions such as 1 7/8 and 25/16 and letter labels (a, b, c, d, e; m, n, o, p, q, r) mark the proportional positions along the arms. The bundle supplies only the numeric and lettered captions of these figures, not connected prose, so the reasoning is carried by the drawings themselves.
On this page
Divided balance beams hung with weights
Several horizontal beams are drawn ruled into equal divisions and loaded with weights, showing how position along the arm governs a weight's effect. One arm carries the ordered points b, c, d, e, a.
Fractional divisions of the arm
The uppermost arm is marked with fractions — 1 7/8, 15/32, 45/32, 3 1/8, 25/16, 20 — quantifying the proportional distances at which weights are placed along the beam.
Weights carried over pulleys
At the right a beam runs over pulleys with weights hung beneath, extending the balance study to cords passing over wheels. Points o, S, t, m, r and a figure number label the arrangement.