The blow of a club, a balance, and a river's surface
Impact grows with distance from its cause; weights on a balance; water wears the bed
In red chalk Leonardo draws a club or cudgel, labelled a and n, and reasons that a blow from a continuous cause grows more powerful the farther it strikes from the source of its motion — stronger at a than at b. A balance carrying a vertical and an oblique weight (a b and c d) shows the two as equivalent. A closing line notes that a river's surface seeks to lie equidistant from the earth's centre and, rebounding, presses upon and wears away the bed.
On this page
A blow is stronger farther from its cause (a, b)
Leonardo argues that the part of a blow born of a continuous cause is the more powerful the farther it lies from the cause of the motion. On the club, marked a n, the blow is stronger at a than at b.
Equivalent weights on a balance (a b, c d)
A balance carries a vertical and an oblique weight; Leonardo sets the weight a b as equal to the weight c d. The letters a b - c d key the two loads to the beam.
A river's surface wears away its bed
The surface of river water, Leonardo writes, desires to be equidistant from the centre of the earth; rebounding, it weighs upon and consumes the bottom. The note ties the level the water seeks to the erosion of the channel.