Water-driven mills and the weight of falling water
Notes on water's perpendicular weight and grinding with little water, amid geometry and later sums
The sheet is a crowded page of small pen studies: geometric constructions with a divided circle and arcs, figures of wheels driven by water, a leaf, and a foreshortened arm or limb. The transcribed notes observe that water's greatest weight is the perpendicular and that water spreading through oblique channels loses force, and propose a way to grind as much with little water as with much. Later arithmetical operations, expressly noted as not in Leonardo's hand, fill the lower portion when the sheet is turned; the Codex Atlanticus classification also notes rammers for a spingarda.
On this page
Water's greatest weight is the perpendicular
A note at the top states that the greatest weight water has is the perpendicular, and that water spreading more widely through oblique channels grows correspondingly weaker. The thought is left unfinished on the sheet.
Grinding with little water
Beside figures of wheels driven by water, a caption proposes a way to grind as much with little water as with much. The adjacent sketches show water-wheels and mill gear.
Divided circle and arc constructions
Among the sketches are geometric figures: a circle marked off into segments and a set of intersecting arcs and radii drawn in compass work, standing apart from the machine studies.
Later arithmetical operations (not Leonardo's)
When the sheet is turned, columns of multiplications and sums appear at left and right. These are expressly recorded as operations not by Leonardo, added by a later hand.