Sea raised by the sun, discharge and fall, and river eddies
The equinoctial sea rising, a proportion of flow to fall per mile, and why salt water resists weight
The page opens with the claim that the sea beneath the equinoctial rises through the sun's heat, drawing water from every side to level itself and restore its spherical perfection, followed by a proportion problem: if a water-mouth discharges 16 measures with a fall of 16 ounces per mile, how much will it give with a fall of 8 ounces? A second note, illustrated by a coiled eddy at the upper right, states that transverse whirlpools gain breadth and slowness along their length and that bubblings rising from river beds destroy the longitudinal eddies. Leonardo adds that sea and turbid water, being heavier, resist carried weights more, the salt being inseparable without drying heat while turbidity settles out with heat and stillness.
On this page
Transverse and longitudinal eddies
The revolutions of transverse eddies gain in breadth and slowness at every degree of their length. The bubblings of water reflected up from the beds of rivers destroy the circulations of the longitudinal eddies.
Why sea and turbid water resist carried weights more
Sea and turbid river water are heavier than other waters and so resist the weights they carry. The sea resists most because its dissolved salt is inseparable without heat to dry the water, whereas turbidity separates out through heat and stillness.
Proportion of discharge to the fall per mile
A water-mouth that yields 16 measures when the fall is 16 ounces per mile is asked how much it will yield when the fall is reduced to 8 ounces per mile. The problem sets a proportion between the rate of fall and the volume delivered.
The sea rises beneath the equinoctial through the sun's heat
The sea under the equinoctial line rises through the heat of the sun, taking its motion from every part of the swell. It rises to level itself and restore the perfection of its sphere.