The statics of water: vessels, counterweights and spinning machines

A prophecy: 'All the astrologers will be castrated'

In the upper right, under the heading 'On prophecy,' Leonardo writes one of his riddling prophecies: 'All the astrologers will be castrated — that is, the cockerels.' The joke turns on the play between astrologers and cockerels (galletti).

Grades of weight from water to stone

The same note observes that between water and stone of equal quantity there are almost infinite grades of weight, as many as there are grades of density — from pure water, to mud, to hard earth, to the densest stone, and on into the metals.

Water rises in mountains as sap in plants and blood in animals

A note at the foot compares water rising into mountains to sap climbing from the roots to the tops of plants — shown in cut vines — and to blood in animals, likening the earth to a living body.

Water does not press its full weight on a vessel's floor

Beside a rectangular 'parallel vessel,' Leonardo argues that when water presses against the walls it loses weight upon the bottom, so the floor does not bear its whole weight. An experiment with a holed vat tests whether the water above the hole truly weighs upon it.

A counterweight cannot lift water to its own height

Studies of chain-of-buckets and counterweight machines conclude that water raised by a counterweight can never equal that counterweight's weight; better to spend the effort lifting water directly. In one case the counterweight m c weighs four times the water c n, so the water leaps four times higher.

Spinning machinery: reels, spindles and bobbins

Along the sheet are sketches of textile machinery labelled 'yarn-winders' (arcolai) and 'spindles' (fusi): a cylinder drawing the threads of four spindles ('way of reeling') and another drawing seven threads ('way of making the thread onto the bobbins').

Angolo superiore destro:

Al centro margine inferiore:

A sinistra, sezione di vaso rettangolare:

Figure di sezioni di vasi comunicanti, con:

Particolare di macchina per filare, con:

A sinistra contrappeso e bilancia applicati al fondo forato d'un recipiente d'acqua:

Figura di secchielli in catena mossa da un contrappeso:

Margine destro, in basso. Vasi comunicanti di varia sezione, con:

Figura analoga e aggiunto recipiente per raccogliere l'acqua espulsa, con:

Sopra il testo precedente, particolare di macchina, con:

Cilindro che trae i fili di quattro fusi, con:

Margine sinistro. Altro cilindro che trae sette fili:

Angolo inferiore lacerato.

Upper right corner:

At the centre of the lower margin:

On the left, section of a rectangular vessel:

Figures of sections of communicating vessels, with:

Detail of a spinning machine, with:

On the left, a counterweight and balance fitted to the perforated bottom of a water container:

Figure of buckets in a chain moved by a counterweight:

Right margin, below. Communicating vessels of varied section, with:

An analogous figure with an added vessel to collect the expelled water, with:

Above the preceding text, detail of a machine, with:

A cylinder that draws the threads of four spindles, with:

Left margin. Another cylinder that draws seven threads:

Torn lower corner.