Lever and counter-lever: the potential arm equals the real arm
A balance note on the proportion of arms to weights
The left leaf (119v) is nearly blank apart from show-through and a B.M. stamp, while the upper right of 116r carries a brief note beside two small mechanical sketches: a balance-beam with a suspended weight and pulley, and a bracketed triangular support. The note states the principle that the weights carried are in the same proportion as the potential arm to the real arm, taking the potential arm a d as equal to the real arm a b. Further untranscribed drawing outlines are faintly visible on 116r.
On this page
Weights in proportion to the arms
The proportion the potential arm bears to the real arm is the same as that of the weights dispensed between them. Here the potential arm a d is taken to be equal to the real arm a b.
Balance-beam with weight and pulley
At the top right of 116r a small balance-beam is drawn with a weight hung at one end and a pulley at the other, beside a bracketed triangular support. The sketches illustrate the lever proportion set out in the adjacent note.