On weights: lever and counter-lever in equilibrium
How 1800 and 100 pounds balance on an 18-to-1 beam, and what happens when the lever is divided
The sheet is headed De ponderibus (On weights) and works out the statics of a balance beam split into a short counter-lever arm and a long lever arm. Leonardo claims that 1800 pounds hung at the top of a counter-lever of one braccio balance 100 pounds set at the end of a lever 18 braccia long, then examines how halving the beam changes the loads that stand in equilibrium, finding that 25 can do the office of 200. A graduated horizontal scale marked with the values (100, 200, 1800) runs across the right leaf, and a framed lever apparatus lettered m and S is drawn at the upper left. Further untranscribed notes surround the diagrams.
On this page
The lever balances the counter-lever
With one braccio of counter-lever and eighteen of lever, 1800 pounds hung at the top of the counter-lever balance 100 pounds set at the top of the lever, so that lever and counter-lever stand in equilibrium. The graduated beam drawn across the right leaf carries the marked values 100, 200 and 1800.
Dividing the beam: 25 does the office of 200
If the beam is divided into two equal parts, the second half needs only 200 on the counter-lever, and with one braccio of counter-lever against eight of lever, 25 will stand equal to 200. Leonardo calls this strange to propose, and notes that beyond a two-part division no further increase results.
Equal descent, greater strength
The lever divided below, with an equal descent, raises its counter-lever as high as the undivided one, yet Leonardo judges it stronger by three quarters than the continuous beam. The heading De ponderibus announces the whole discussion of weights.