Force of enclosed water; falling weights and hung loads
An experiment to weigh water's thrust on each side of a square vessel, with lever, pulley and falling-weight studies
Folio 149v mixes statics with a hydraulic experiment. A large box labelled 'acqua' illustrates a scheme for weighing the force enclosed water exerts on each of a square vessel's five sides by making one wall movable and weighing it. Around it, articulated levers and pulleys carry hanging weights (marked 4, 8, 100), with questions on how a suspended hundred-pound load charges its two supports and on the twin weights that hollow their target in proportion to their size. A final note asks why torn cloth tears along right angles, because it is woven in right angles.
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Weighing water's thrust on each side of a vessel
To learn the force of water enclosed in a square vessel, make one side movable, fastened with thin leather, then fill the vessel and weigh that side. Knowing one side gives the other three; and subtracting the four sides' weight from the water's weight yields what rests on the bottom. By experiment you gain true knowledge of the weight the water gives to each of the five enclosing sides.
Twin weights and the depth of their impact
Two weights of equal thickness but double length and weight fall from an equal height onto something that yields equally to the impact of their descent. It follows that the hollow made by the greater weight must be double the hollow made by the lesser.
How a hung hundred-pound load charges its supports
With a hundred pounds suspended in the position drawn, the question is how the load's two supports will be charged. Adjacent lever-and-pulley figures are set with weights (4, 8) chosen so the cords and loads stay in the shown position.
Why cloth tears along right angles
Why, when a hook catches cloth or a rag is torn, do the lines of the tear run from the right angle? Leonardo answers that it is because such cloth is woven entirely in right angles.