Spoon Catapult (Cimitrilla) and the Physics of Percussion
Whether the stone is thrown by the blow alone, and how impetus follows a straight line
Leonardo studies the spoon-catapult he calls a 'cimitrilla', asking whether its stone is driven by the simple blow alone or by an added continuing motion. He proposes a test: watch whether the flying stone falls back onto the point m from which it left, in which case the blow alone drove it; if it travels along md or mr, some extra motion helped. He states that a moving body follows the straight line of its mover for as long as it keeps the impressed impetus, and asks why a body released from a curved path flies off straight. A lever-and-sling catapult is drawn at upper right, and a faint male profile in red chalk lies beneath the pen writing.
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The spoon catapult ('cimitrilla')
The lettered device n d r - f m is a spoon-catapult, or cimitrilla, drawn at the upper right. When the blow is delivered at f with great force and impetus, its motion arises at the right angle m and carries the stone to n.
Testing whether the blow alone throws the stone
To learn whether the stone leaves by the simple blow or by the blow plus some consequent motion, Leonardo says to watch whether the flying stone falls back on the place from which it departed. If n falls back at m, the percussion alone drove it; if it moves along md or mr, an added motion increased it.
Impetus follows the straight line of its mover
As long as the moving body keeps the impressed impetus, it follows the straightness of the line of the mover from which it separated. He then poses the question: why, when a mover is given a curved path, does the released body fly off along a straight line?
Male profile in red chalk beneath the writing
Beneath the pen writing a profile of a male face is drawn in red chalk. Its faint reddish outline shows the nose and brow near the center of the page.