VENI VIDI DA VINCI

Collections Newsletter Guild About Developers Patron Sign In

Library/Codex Forster I/048v

Prev98 / 114Next

Codex Forster I — 048v

100%

Reset zoom

© Victoria and Albert Museum, London

De ponderibus.

Se sono 2 omini che tenghino un lenzuolo per le tese, nel quale lenzuolo [s]ia un om che pesi 200 libbre, e ciascuno tiri tanto l'estremità che 'l peso non tocchi terra, sappi che ciascuno tiratore ha per sé peso quanto pesa l'omo di mezzo, imperò che lui sostiene mezzo l'omo di mezzo e mezzo l'avversario tiratore, che pare che 'l peso di mezzo, sendo 200, poiché ciascun tiratore n'ha 200, si facci 400.

Modi di misurare un'altezza.

Diagramma per traguardare una torre, con:

e f - a b - c d

Fa che e f sia la torre che vuoi misurare. Allontanati a tuo modo e mettiti ne lo orecchio1 come appare c b a, che sia lungo un braccio e alto 1/2, e fa che la torre entri fra b a. Di poi volgi la linia b a per lo piano de la terra, e tan[to] quanto quella occupa del terreno, tanto occupava de la altezza, e nello occupato terreno troverai la vera altezza della torre.

On weights.

If there are two men holding a sheet by its ends, in which sheet lies a man who weighs 200 pounds, and each pulls his end so much that the weight does not touch the ground, know that each puller has for himself a weight equal to the man in the middle, because he sustains half of the middle man and half of the opposing puller; so it appears that the middle weight, being 200, since each puller has 200 of it, comes to make 400.

Ways of measuring a height.

Diagram for sighting a tower, with:

e f - a b - c d

Let e f be the tower you wish to measure. Move off as far as you like and set to your ear, as shown by c b a, an instrument one braccio long and half a braccio high, and make the tower fall between b and a. Then turn the line b a down onto the plane of the ground, and as much of the terrain as it occupies, so much did it occupy of the height; and in the ground it occupied you will find the true height of the tower.

On Weights, and How to Measure a Tower's Height

A puller of a suspended 200-lb man bears the whole weight; a sighting method for a tower

Physics & Mechanics Geometry

A page of continuous text opening 'De ponderibus' works through a weight problem: two men hold a sheet between them carrying a 200-pound man, and Leonardo reasons that each puller effectively bears the full 200 pounds, so the load appears to become 400. The text then turns, under the heading 'Ways of measuring a height,' to a surveying method illustrated by a small sighting diagram lettered e f, a b, c d for finding the height of a tower. The writing is in Leonardo's mirror hand.

On this page

The sheet, the 200-pound man, and the pullers (De ponderibus)

Two men hold a sheet by its ends with a man of 200 pounds lying in it, each pulling so the load clears the ground. Leonardo argues each puller carries as much as the whole middle man, since he supports half the man and half the opposing puller, so the 200-pound load appears to make 400.

Sighting instrument to find a tower's height (e f, a b, c d)

Letting e f be the tower, one stands off and sights it through a device c b a, one braccio long and half high, so the tower fits between b and a. Turning the line b a down onto the ground, the ground it covers equals the tower's height.

Reader's Edition — described with AI from the e-Leo transcription.