Definitions of Motion and Blowpipes for Pellets
Impetus, percussion and rebound; two bows and cerbottane; mixed natural and accidental motion
Leonardo opens with crisp definitions: motion is change of place, impetus the increase of velocity, percussion the end of motion, and rebound the resurrection of motion. Two bow-like launchers are drawn at the right, which the note beside them calls blowpipes for pellets (cerbottane da ballotte), and a query weighs whether the pellet flies farther when it leaves the arrow or after the arrow strikes a bore. Lower zigzag diagrams illustrate mixed motions, natural blended with accidental and its reverse, and a neutral mixed or double motion.
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Definitions of motion, impetus, percussion and rebound
Motion is defined as change of place, impetus as the increase of velocity within motion, percussion as the end (limit) of motion, and rebound as the resurrection of motion. A question follows about which small projectile travels farther, the one leaving the arrow while the arrow stays on the string, or the one that flies on through a bore after the arrow stops there.
Two bows drawn as blowpipes for pellets
The note beneath the two drawn launchers identifies them as blowpipes for pellets. Some believe that, when the same weight is discharged from such instruments by the same force, the proportion of the resulting motions equals the proportion of the lengths of the blowpipes.
Natural and accidental motion mixed
Natural motion mixed with accidental occurs when a thing descends then rises again, descending one braccio and rising half. Accidental mixed with natural is the reverse, rising one braccio and descending half, continuing so over a long span; a neutral mixed motion is called double.