The pyramidal law of accelerating fall
A column of circles and an acute triangle chart the velocity gained at each degree of descent
The folio defines the "motion of discrete quantity": a heavy body in natural fall acquires a degree of velocity at every degree of descent. A marginal column of numbered circles (labelled 1 through 8) and an acute triangle ruled with parallels down to a base numbered 1 to 8 represent this gain, whose growth is pyramidal — a degree of width added at every degree of length — and follows arithmetical proportion, the excesses always equal. A note added in darker ink at the top states that the penultimate term stands to the last as the first stands to the second.
On this page
Velocity acquired at every degree of descent
The natural motion of heavy objects gains a degree of velocity at each degree of descent, defining what Leonardo calls the motion of discrete quantity. The accumulating power of the fall is what the accompanying figures are meant to picture.
The pyramid as image of uniformly gained power
The motion is represented by a pyramidal shape, for the pyramid grows in the same manner: at every degree of its length it acquires a degree of width. The acute triangle ruled with parallels down to a base numbered 1 to 8 makes this growth visible.
Proportion of the penultimate to the last term
A note added in darker ink at the head of the page states that the penultimate has the same proportion to the last as the first has to the second. It sets the ratio governing the numbered series charted below.
Column of circles numbering the degrees of descent
A column of equally spaced circles marks the degrees of descent, labelled from the second circle as 1, 2, 3, 4, 5, 6, 7, and 8. It runs beside the triangle so that circles and parallels correspond degree for degree.