Geometry is infinite; the arithmetic of discontinuous quantity
Continuous quantity infinitely divisible; discontinuous quantity begins at unity
Two open angles head the page, one inscribed 'Arithmetic' and carrying the series 1 2 3 4 5 6 7 8, the other inscribed 'Geometry'. The geometry note argues that geometry is infinite because every continuous quantity is infinitely divisible in both directions, whereas discontinuous quantity begins at unity and grows to infinity. Leonardo adds that if given a line of twenty braccia he would undertake to make one of twenty-one, illustrating unbounded increase.
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Geometry is infinite
In the angle inscribed 'Geometry', Leonardo argues that geometry is infinite because every continuous quantity is infinitely divisible, both in one direction and in the other. He contrasts this with discontinuous quantity, which begins at unity and increases to infinity, and offers that given a line of twenty braccia he would make one of twenty-one.
Arithmetic and the series one to eight
A second open angle is inscribed 'Arithmetic' and carries the number series 1 2 3 4 5 6 7 8. It stands for discontinuous quantity, which begins at unity and grows without end.