Rebound of falling water and a glass-walled vessel
Falling water returns only as droplets that leap higher; observed through a four-plate glass tank
Leonardo proposes observing the behaviour of moving water through a vessel built of four glass plates, watched from the side. In the note headed 'On motion' he reasons that water falling from the height of one braccio never rebounds to its original height except as small droplets, which leap much higher because the rebound is faster than the descent, since the falling water drags down a great quantity of air. A pen sketch of a rectangular vessel and swirling, cascading water accompanies the text, with red vertical hatch-strokes at the left. A single word in red chalk, 'bolori', is added beneath the pen writing.
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A four-plate glass vessel for watching water
The reader is told to make the experiment with a vessel constructed from four plates of glass and to observe the water from the side. The transparent walls would let the internal motion of the water be seen directly.
Falling water rebounds only as droplets
Water dropping from the height of one braccio never returns to a like height except in small droplets, which spring up much higher. Leonardo argues the rebound is far swifter than the fall because the falling water carries down a great mass of air with it, and once struck the water leaps back up.
Sketch of the vessel and cascading water
Below the upper lines a pen drawing shows a small rectangular vessel and a plume of swirling, spilling water, illustrating the cascade and its rebound. Short red vertical hatch-strokes stand at the left margin of the drawing.