The Restless River: Erosion and the Making of Clouds
Water gnawing its banks and rising as vapour, with a geometric figure on the facing sheet
In a single flowing passage Leonardo describes the river forever at work, gnawing its northern bank, undermining the southern, bubbling up toward the sky, spiralling in circular eddies, stealing tilled fields from the farmers on one side and dumping the plundered soil on the other, never at rest. He then follows the water through all its states: falling as rain, snow and hail, gathering thin mists into thick clouds, and rising as vapour with the warm element until the cold region compresses it, likened to a hand squeezing a soaked sponge, so that the enclosed air bursts out and drives the clouds like a bellows. The facing page carries a large geometric line-figure, a slender triangle closing on a circle, which the transcription does not include.
On this page
Water gnawing now the north bank, now the south
The river is shown turning to the north to gnaw the foot of its banks, then to the south so the opposite bank collapses, sinking toward the earth's centre and leaping back to the sky in bubbling. With circular revolution it confounds its own course, forever removing or consuming whatever borders it, now turbulent and ruinous, now clear and gentle among fresh grasses.
The water cycle and the sponge of the cloud
Water is traced through rain, snow, hail and fine mist that composes thick clouds. Rising as vapour with the warm element into the cold region, it draws together; and as a hand squeezes a soaked sponge, the cold compresses the moisture until the enclosed air bursts through the weaker parts and blows like a bellows, driving the lighter clouds apart.
The river carrying off tilled soil and depositing it
From the western side the river widens and takes the tilled fields from their farmers; from the eastern it unloads the plundered soil. Thus it digs and fills, takes here and lays there, ceaselessly reshaping the land it borders.
Slender triangular line-construction with a circle
The right-hand page bears a large, faint geometric figure: a long slender triangle built of ruled lines converging on a circle at its lower end. It is drawn without transcribed lettering and is not addressed by the water text.