Clockwork devices and a definition of discontinuous motion
Cords that must be iron rods, and a back-and-forth motion likened to a bell
A folio of mechanical studies dominated by clock-like devices: a geared assembly, a spring drum with a ratchet-toothed wheel, and a barrel-shaped mechanism holding several wheels driven by a hand crank. One note warns that the cords a b c d must actually be iron rods fixed to the instrument so the turning handle does not flip the device over. A longer passage sets out a 'definition of motions', distinguishing discontinuous back-and-forth motion (like a bell) from motion that never leaves its mover, as in a clock's lever and counter-lever.
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Cords a b c d must be iron rods fixed to the frame
The cords labelled a b c d must be irons joined to the instrument above. If they were not, the turning handle would drag the whole device partly upside down. The note fixes a mechanical detail of the crank-driven mechanism drawn at the right.
Definition of discontinuous motion, like a bell
Discontinuous motion runs from right to left and back, coming and going like a bell. It comes in two kinds: one equally powerful in going and returning (the bell's incident and reflected motion), the other more powerful going than returning and never separating from its mover, as in the clock lever with its counter-lever.