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Paris Manuscript L — 149

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Bibliothèque de l'Institut de France, Paris

Capovolto.

In Romagna, capo d'ogni grossezza d'ingegno, usano i carri di 4 rote, e quali n'hanno 2 dinanzi basse e due alte dirieto. La qual cosa è in gran disfavore di moto, perché in sulle rote dinanzi si scarica più peso che in su quelle dirieto, come mostrai nella prima del quinto delli Elementi1. E esse prime rote so[n] di m[o]vimento men facile che 'l moto delle rote grandi, sì che a crescere peso dinanzi e diminuire potenzia di moto, la difficultà si raddoppia.

Schemi dimostrativi del peso sulle ruote, con:

3 - 2 - 44

Qui la rota maggiore ha 3 tanti più lieva che la rota minore, onde la minore fia di 3 tanti più difficultà, e aggiuntole, dell'ottocento2 libbre, 200 più alla minore, vedi quel che fa.

Inverted.

In Romagna, chief of every crudeness of wit, they use carts of four wheels, of which they have two low in front and two high behind. This is greatly unfavourable to motion, because more weight is discharged upon the front wheels than upon those behind, as I showed in the first [proposition] of the fifth [book] of the Elements. And these front wheels are of less easy movement than the motion of the large wheels, so that, by increasing the weight in front and diminishing the power of motion, the difficulty is doubled.

Demonstrative diagrams of the weight on the wheels, with:

3 - 2 - 44. Here the larger wheel lifts three times more than the smaller wheel, whence the smaller is of three times more difficulty; and adding to the smaller, of the eight hundred pounds, 200 more, see what it does.

Why Romagna's four-wheeled carts move badly

A note on mechanical disadvantage, citing Leonardo's own 'Elements'

Physics & Mechanics Machines & Devices Arithmetic & Proportion

Leonardo faults the carts of Romagna, which run on two low front wheels and two high rear wheels, arguing that this throws too much weight onto the small front wheels and doubles the difficulty of moving them. He supports the claim with a rule from the fifth book of his own 'Elements' and with a worked example. A demonstrative diagram compares a larger and a smaller wheel, the larger lifting three times more, using figures of 800 and 200 pounds. A loosely drawn hatched form occupies the centre of the leaf and is not described in the transcription.

On this page

Weight thrown onto the small front wheels

The Romagna cart carries two low wheels in front and two tall ones behind, so more of the load bears on the front pair. Because small wheels also turn less easily than large ones, increasing the front weight while lowering the driving power doubles the difficulty of motion.

The larger wheel lifts three times more

In the demonstrative scheme the larger wheel raises three times as much as the smaller, so the smaller labours three times harder. Adding 200 pounds more to the smaller wheel's share of the eight hundred, he invites the reader to judge the result. The scheme is labelled with the figures 3, 2 and 44.

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