River currents: width, depth and reversed flow
Two propositions on the surface motion and speed of water over an unequal river-bed
A hydraulics page pairing a pen note with two numbered propositions and two drawings of a hollowed river-bed. Leonardo states that water which exceeds the general width and depth of rivers will turn into a contrary course. Propositions 6 and 7 add that water of equal width but unequal depth keeps equal motion at its surface, and that among currents of equal slope the one of straightest motion is the swiftest.
On this page
Water exceeding a river's width and depth reverses its course
That water which passes beyond the general width and depth of rivers will turn back into a contrary course. The point is illustrated by pen and red-chalk sections through a hollowed river-bed.
Equal width and unequal depth: equal surface motion (props. 6-7)
Water of equal width and unequal depth will have equal motion at its surface. Among currents of equal obliquity, the one of straighter motion will be the swifter.