If the earth were a perfect sphere the waters would cover it
Mountains, perpetual sea beds, and how bodies drift between two currents
Leonardo reasons that if the earth were spherical no part of it would stand uncovered by the sphere of water, and that even over a perfectly flat plain water rests in a convex figure, so no truly flat surface can be found on any great sea. A note beside a small semicircle observes that what looks flat is in fact a steep mountain, that the low places of the sea bed and the mountain peaks are perpetual, and that in time the earth will become spherical, wholly covered by water and uninhabitable. A third block treats bodies carried in a current: an oblique body descends toward the bottom, a body between two equal currents drifts without overturning, and one between two unequal currents turns continually.
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A spherical earth would be drowned by its own water
If the earth were spherical no part of it would be uncovered by the sphere of water; over a perfect plain the water stands convex in the middle, and it is impossible to find any flat part on the surface of however great a sea.
What looks flat is a steep mountain; sea beds are perpetual
Beside the semicircle marked a n p, n o, q, a note states that what appears flat here is a steep mountain, that the low places of the sea bottom and the mountain peaks are perpetual, and that the earth will become spherical, wholly covered by water and uninhabitable.
Bodies carried between equal and unequal currents
A body carried by the water descends toward the bottom if oblique. Only a body midway between two equal currents travels without overturning; one between two unequal currents is in continual revolution between below and above.