Recoil, off-centre weight, and the arc of suspended bodies
Bombard recoil, weight cast outside the centric line, and a figure of accidental versus natural motion
A page of Moto propositions closing with a marginal figure labelled 'Accidental motion. Natural.' Leonardo notes that a bombard recoils farther the sooner the fire catches within it, and that a self-moving body places the greater share of its weight between the centric line of its support and its goal, moving faster the more weight it casts outside that line. He compares the cumulative effect of equal motors over long and short times, discusses swings that pass beyond the perpendicular and return, and repeats that the arc of a suspended body's motion is always higher toward its beginning.
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Recoil of a bombard on firing
That bombard recoils the more backward in which the fire catches the more quickly. The proposition treats gun recoil as a case of motion set going by a sudden internal force.
Weight cast outside the centric line
The greater weight of any body moving by violence lies between the centric line of its support and the place it seeks to go; a body that puts more of its weight outside that centric line moves the faster.
Accidental and natural motion diagram
A small figure at the lower right, a triangular frame with a plumb line, is captioned 'Accidental motion. Natural,' distinguishing the slanting driven path from the vertical fall. It accompanies the text on swings that pass beyond the perpendicular and return.