Notebook on Mechanics and Natural Philosophy

This other [arrangement] is of such a nature that the weight which is attached to these cords shall be equal to the weight that supports it; and weight 1 shall be equal to 3, and weight 1 shall also be equal to weight 4, or rather weight 4 shall be equal to 3, and thus for every space they shall be equal among themselves.

Every segment of the cord weighs as much as the other, or rather one cord pulls as much as the other, as is demonstrated in weight 1, weight 4, and weight 3, which are equal among themselves because their cords pull through an equal distance and with equal power power original: "potenza"; in Leonardo's mechanics, this refers to the force or effort exerted to achieve balance..

Each of these two cords supports half original: ".1. 1/2"; Leonardo's notation here likely signifies "1 [part of] 2" or "half," as the logic follows that two cords share the load of one weight. of weight 3, and each of the supports of said cord similarly supports half, and the supporting weight 3 shall be equal to weight 4 and to weights 2 and 1; and weight 4 shall also be similar to 2 and 1 and similar to 3, because the movement of cord f-g-h is similar to the movement of weight 3, and the movement of cord a-b-c-d is similar to the movement of weight 4, and the movement of weights 1 and 2 together is similar to the movement of weight 3 or 4; from which it follows that weights 3 and 4 shall be equal to 2 and 1, and because the two cords support two weights, namely 3 and 4, these cords are loaded with the gravity original: "gravità"; meaning the heaviness or downward force. of said weights, and weight 1 supports half of it and weight 2 supports the other half.

Experience demonstrates and reason confirms that weights 3 and 4 are equal to weights 1 and 2, because if you lower weight 3 and 4 by a certain distance space original: "spatio"; Leonardo uses this to describe the distance or displacement of a weight., weights 1 and 2 will rise by the same distance, and by joining weight 3 to 4, they will be equal to 2 and 1 joined together. Therefore, for the reason recorded, there shall be equal movement and consequently equal weight. And it could also be proven by saying: cord d-c-b-a supports weight 4 and gives half of it to pivot pivot original: "polo"; literally "pole," here referring to the point of support or the axis of the pulley wheels. a and the other half to pivot d; and the same shall be for cord f-g-h which supports weight 3 and gives half of it to pivot h and the other half to pivot f; and because pivot a and pivot h are loaded upon weight 2, that weight 2 shall be equal to the two pivots a-h which are half of those weights 3 and 4; and because the other two pivots d and f are loaded upon weight 1, that weight 1 shall also be equal to them.