Departure for Rome; leaping, the weighted foot, and the vacuum
Leonardo leaves Milan in 1513; jumping off a falling body, the foot under load, and the power of the vacuum
The folio opens with Leonardo's note that he set out from Milan for Rome on 24 September 1513 with Melzi, Salai, Lorenzo and Il Fanfoia, then asks whether a man standing on a rapidly descending body can leap free of it, concluding that the leap must outpace the descent. A further passage describes how the flesh of the weight-bearing foot spreads and lowers between bone and ground. The page closes with 'the power of the vacuum generated in an instant,' citing a lightning strike on a Milan tower that tore out a section of wall, the same effect being ascribed to the bombard. The image is dense mirror-script text without diagrams.
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Departure from Milan for Rome, September 1513
Leonardo records that he left Milan for Rome on 24 September 1513 in the company of Giovan Francesco de' Melzi, Salai, Lorenzo and Il Fanfoia. The note fixes the date and travelling companions of his move toward the papal city.
Leaping from a rapidly descending body
Leonardo asks whether a man whose feet rest on something descending at speed can separate from it by jumping upward. He answers yes, provided the motion of the leap is faster than the motion of the descending thing from which the leap springs.
The foot that bears the weight
The loaded foot is always broader and lower than the unloaded one, its widening and flattening produced in the flesh enclosed between the bones and the ground. He adds that extended limb-flesh undoes its muscles while curving flesh generates them, though nothing of this shows in the weight-bearing sole.
The power of the vacuum created in an instant
Leonardo reports seeing a thunderbolt strike the north side of the Tower of the Credenza at Milan, tearing a space of three braccia from a wall four braccia thick, an effect he attributes to the vacuum left by the flame. He notes finding the like in rocks of the high Apennine and ascribes the same behaviour to the bombard.