Descent of arrows and their penetration into the ground
Penetration proportional to crossbow load, with a tinned-tube drop experiment
On the recto Leonardo works out the ballistics of arrows shot from a crossbow, arguing that an arrow's penetration into uniformly resistant ground is proportional to the height of its descent and to the weight used to load the bow. A tall diagram of arrows falling along vertical lines accompanies a small sketch of a crossbow with lettered loads. At the foot he proposes an experiment using a tinned-sheet tube loaded with 4-ounce weights to test descent and penetration in double, triple and quadruple proportion.
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Penetration follows the descent on uniform ground
Where an arrow falls perpendicularly onto ground of equal resistance, its penetration is held to match its descent. Arrows of equal weight released from double the height drive twice as deep, and a doubled descent is equated with doubling the arrow's weight at equal thickness and double length.
Crossbow load governs the arrow's rise and flight
The rise of the bowstring toward its nut, and the ground-penetration of the shot arrows, are held proportional to the weights used to draw and load the crossbow. Increasing the arrow's weight in step with the draw weight preserves the proportion of the motions, provided the arrow stays of equal thickness.
A tinned-tube experiment on descent and penetration
Leonardo proposes a tube of tinned sheet metal weighted to 4 ounces, its hollow long enough to hold eight weights of 4 ounces each, in order to test descent and ground-penetration in double, triple and quadruple proportion. One is to increase and decrease the load and note both the descent and the penetration.
Falling arrows and a small crossbow
A row of arrows is drawn falling along long vertical lines, beside a small sketched crossbow with lettered loads. The figures carry numeric labels (500 and 100 braccia) and the letters a, b, c running down the sheet.