Coiled springs, spring-driven wheel and chisel percussion
Notes on how coiled springs extend, a key-wound wheel, sound, and oblique cutting
The page continues Leonardo's study of coiled ('reverting') springs, showing helical and snail-shell spring forms together with drums and chain segments. Notes reason that a single force extends many coils as easily as one, and that a many-turned spring behaves like a single-turn spring of equal thickness. A key-wound wheel is described, an observation is made that the ear is deceived by the 'perspective' of a voice, and a rule is stated that the more obliquely a cutting iron strikes wood, the deeper it sinks.
On this page
Wheel wound by a key
A note in the upper right margin explains that the wheel is loaded, or wound, by the key that turns its axle. It accompanies drawings of coiled springs mounted on drums.
Extension of coiled springs
Leonardo argues that one and the same force extends very many coils of a coiled spring as easily as a single coil, and that a spring of many turns behaves like a spring of similar thickness with a single turn. A companion note treats how far a single coil, or a snail-shell spring, extends under the same weight.
Oblique blow of the cutting iron
A rule beside the drawings of chisels driven into wood states that the more oblique the blow made by the cutting iron on the wood, the deeper it will sink into the wood. Several chisels are shown embedded at different angles.
The ear deceived by the voice
A separate note observes that the ear is deceived by the 'perspective' of the voice, which seems to move away and yet does not change its position. It stands apart from the mechanical drawings.