Weights of the elements and the crest of a wave
A buoyancy argument in air, water and earth, with wave and calculation notes
A densely written sheet carrying a thought-experiment on the relative weights of the elements: air weighs 2, water 4 and earth 8, and Leonardo works out how to compound air and earth into a mixture that lies level with the water by cancelling their excesses of levity and gravity. Small weight-and-scale diagrams accompany the argument, and a pair of wave drawings lettered a-d-c-b illustrate how the crest of a wave sinks deepest in its fall. A column of figures in the lower corner records the reckoning. The leaf also bears further dense writing beyond the transcribed weight-and-wave notes, and a faint leaf impression at its centre.
On this page
Balancing air and earth to the level of water
With air weighing 2, water 4 and earth 8, Leonardo doubles the quantity of air to obtain 4 of levity above water while the earth has 4 of gravity above water. Removing these equal and opposite excesses leaves a mean equal in weight to the water, so the surface of the mixture and of the water lie level.
When a floating body's gravity is destroyed
Doubling the air makes a mixture of air and earth; without it the earth, twice as heavy as water, is only lightened by 2 and surpasses water in sesquialteral proportion. When a heavy body sustained on water has its highest point at the water's surface, it has destroyed its gravity and is of weight equal to the water.
The crest of a wave sinks deepest in its fall
Between two drawings of waves lettered a-d-c-b, Leonardo notes that the wave has its crest which, in the fall, sinks and descends deeper than any other part of it.
Mixing levity and gravity to equal water
Leonardo states that he has 4 of levity and 8 of gravity, and mixing the one with the other and placing it among water that had 4 of gravity, the mixture of air and earth remains equal and becomes equal to the water.