Breaking Cords, Pulleys and a Balance; a Map and the Prophecies
Where a loaded cord snaps, the precise balance, a map of the Taurus, and riddling prophecies
The upper half of this torn sheet studies the mechanics of loaded cords, pulleys and the balance: where a cord of uniform strength will break, how a hanging cord discharges all its weight onto its fastening, friction across pulleys, and a large circle enclosing a 'precise balance'. Turned ninety degrees, the lower half carries a small map of the Taurus region with mountain and river names (Tigris, Euphrates) and rocky peaks, alongside three dense columns of Leonardo's Prophecies, riddling paragraphs on ants, bees, sheep, nuts, swaddled infants, cats and beaten donkeys, closing with a plan for dividing the prophecy. A number table pairs powers of ten with their tenths.
On this page
A cord of uniform strength breaks at its fastening
A cord of uniform strength, overcome by its own weight, always breaks at its point of attachment. Working through a 4-pound cord divided into quarters, Leonardo shows that the whole weight is discharged onto the support, so the cord must fail there.
Four pulley cords n a b c and the toll of friction
Of four cords n a b c carrying equal weights, the mover n suffers most because it feels the friction of 400 pounds and wears out fastest, so it breaks where it parts from its pulley o. Leonardo reckons how the driving excess is diminished by the friction of the pulleys f and r, citing the fifth proposition of the third book of his Mechanical Elements.
The precise balance drawn within the great circle
Within the large ruled circle Leonardo sketches a balance and claims the circumference can be divided into many equal parts with a single opening of the compass, using no other lines or instruments. He adds that neither the size nor the number of such parts can be promised in advance.
A map of the Taurus with its mountains and rivers
The rotated lower half opens with a small geographical map labelling ranges and rivers of Asia Minor and Armenia, among them Antitaurus, Argaeus, the Gordyaean mountains, the Tigris and the Euphrates, with the cardinal winds. A drawing of rocky peaks is named Goba, Arnigasar and Carunda.
Prophecies of ants, bees, sheep and swaddled infants
Each riddling paragraph hides a homely fact behind an ominous tone: peoples hiding food in dark caverns are ants, plundered and drowned creatures are bees, slaughtered little ones are lambs, and the swaddled infants tightly bound by people who cannot understand their tongue are the citizens of sea-cities. The bitter apostrophe on beaten donkeys laments a nature that is stepmother to some of her children.
Of dreaming, and the division of the prophecy
Under 'Of dreaming' Leonardo lists the marvels men seem to experience asleep, rising in flight, hearing animals speak, running the world without moving, before exclaiming at the frenzy of the human species. A separate note divides the whole prophecy into eight parts, from rational animals down to philosophical matters, advising that the great cases be reserved for the end.
