Weights on a Beam Suspended by Two Cords
Rules and numerical tables for how load shifts between the supporting cords
A working sheet on the statics of a uniform rod (asta) hung by cords, crowded with faint red calculations. Leonardo states that a rod suspended by its two ends shares its weight equally, then examines how the load redistributes when one cord is slid along the rod: the transferred weight stands to its remainder as the cord's movement stands to the rest of the rod. Numerous numeric tables of fractional weights (e.g. 6 3/5 and 1 2/5) work out particular cases, and a small pulley-and-cord apparatus at top centre illustrates the arrangement. Further untranscribed figures and numbers cover the sheet.
On this page
A rod hung by its ends shares its weight equally
A rod of uniform weight and thickness suspended by its two ends divides its weight equally between the cords. When one cord moves toward the fixed one, some weight leaves the fixed cord and joins the moved one, in proportion to how far the cord has travelled along the rod.
How weight shifts when a cord is moved
If you move one cord toward the other, weight departs from it and joins the moved cord. That weight has the same proportion to its remainder as the length of rod left outside the cords has to its remainder.
Diminution of weight as the cords approach
As one cord moves toward the middle, the weight leaving the fixed cord relates to the movement as to the span enclosed between the cords. The reduction of weight and the reduction of the cords' distance stay in equal proportion to their wholes.
The quarter-length cord changes the proportion
A movable cord that passes the quarter-point of the rod's length changes the nature of the proportion of its weights with respect to the opposite cord.
Numerical tables of loads on the rod
Repeated columns of fractional quantities (4, 5; 12 1/2; 8; 6 2/5; 128; 400; 20; 32) evaluate the distribution of weight for particular positions of the cords, testing the stated rules numerically.
