Percussion, supports, and a loaded beam
A smaller striking face sinks deeper, props bound together bear more, and the load shared at m, f and n
Folio 189v mixes propositions on percussion with the statics of supports. A long horizontal beam bears a 100-pound weight at m and rests on supports f and n, beneath which Leonardo asks how much of the load each carries; smaller column sketches accompany a rule that twelve props, each bearing one pound alone, bear four pounds each once bound together, and that a support is strongest when the load's centre lies on its central line. Two notes on percussion state that among equal falling weights the one striking with the smaller part of itself sinks deeper, and that a 100-pound hammer sinks further than a 1-pound one only in so far as the air resists it less.
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How much load the supports f and n carry
A beam carries 100 pounds at m and rests on supports f and n; Leonardo asks how much of the hundred each support bears. The letters m, f and n label the beam and its props.
Bound supports each bear more than they could alone
Twelve props, each an ounce in weight and half a braccio long, each sustain one pound on their own. Joined together, Leonardo claims, each will bear four pounds.
A support is strongest under a centred load
A support reaches the highest degree of its strength when the centre of the loading weight lies on the central line of the support.
A smaller striking face sinks deeper
Among equal weights of equal material and drop, the one that strikes its target with the smaller part of itself drives in further. Concentrating the blow on less surface deepens the penetration.