Household accounts with Salaì and Vante, and the physics of impact
Dated loan memoranda on one folio; struck-through notes on infinitely variable percussion on the other
A working sheet that couples household bookkeeping with mechanics. Folio 229v carries three dated memoranda, each opened with a large 'R' for Ricordo: a loan of 4 gold ducats to Vante the miniaturist, carried and handed over by Salaì; a reckoning of mutual debts with Salaì (rose-coloured hose, sums lent at Milan and Venice); and 21 braccia of cloth given for shirts. The facing folio 226r, written sideways in two columns and heavily struck through, argues repeatedly that the percussion, or impact, of a moving body upon its target can vary to infinity even when the bodies, powers, and distances are all equal.
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Loans and cloth reckoned with Salaì and Vante the miniaturist
On 8 April 1503 Leonardo lent 4 gold ducats to Vante the miniaturist, delivered by Salaì into his own hand, to be repaid within 40 days. The same day he gave Salaì 3 ducats for a pair of rose-coloured hose and reckons that, though he still owes Salaì 9 ducats, Salaì owes him 20 (17 lent at Milan, 3 at Venice). On 20 April he gave Salaì 21 braccia of cloth for shirts at 10 soldi the braccio.
Equal powers, yet impact variable to infinity
Although a moving body's percussion upon its object may be caused by equal powers, it does not follow that those powers are not variable to infinity. Even when bodies are equal and brought to the point of impact with equal distance and power, the percussion is still in itself infinitely variable.
Same impulses and distances give endlessly variable blows
Percussions made upon one and the same object can be variable to infinity, even though they spring from the same impulses and the same moving bodies moved through equal distances. Leonardo restates this several times over, striking each version through.
