Rule for antifriction rollers; a bell rung by wind
Staged rollers multiplying force ten-thousand-million-fold; marvels of ingenuity
A long chain of roller stages, each marked 10, runs down the right side of the sheet with a marginal note beside it; such a pivot would let a bell — its opposing weights equal and equidistant from its centre — be rung by a small wind. The left column gives a 'Rule': pivots of the greatest efficacy serve motions that go and return, like bells and saws. One pound of force at b yields ten thousand thousand-millions of pounds at m, and when the first wheel turns a hundred thousand million times the last turns but once — which Leonardo calls the marvels of the art of mechanical ingenuity.
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Roller pivot to ring a bell by a small wind
A staged roller train from b to m, each stage marked 10, runs down the margin. By this means a bell can be set on a pivot so that a small wind will ring it, the bell having its opposing weights equal and equidistant from its centre.
The rule of pivots for reciprocating motion
The 'Rule' states that pivots of the greatest efficacy serve motions that go and return, like bells and saws. One pound of force at b results at m in ten thousand thousand-millions of pounds; and when the first wheel above gives a hundred thousand thousand-millions of turns, the one below gives but a single whole turn.